• TABLE OF CONTENTS
HIDE
 Front Cover
 Title Page
 Foreword
 Preface
 Abstract
 Table of Contents
 List of Figures
 List of Tables
 Acknowledgement
 Introduction
 Readers guide
 Conclusions
 Literature synopsis: Physical...
 Literature synopsis: Water...
 Literature synopsis: Biotic...
 Literature synopsis: Sediments
 Data management and analysis
 Materials, methods and analytical...
 Results and Discussion: Physical...
 Results and Discussion: Water...
 Sediments
 Results and Discussion: Biotic...
 References
 Appendix A: Phytoplankton species...
 Appendix C: Benthic macrofauna...
 Appendix D: Significant correlations...
 Appendix E: Significant correlations...
 Appendix F: Correlation of Chlorophyllls...
 Appendix G: Spatial and monthly...
 Appendix H: Spatial and Monthly...
 Appendix I: Number of zoolplankton/liter...
 Appendix J: Spatial and monthly...






Group Title: Technical paper - Florida Sea Grant College Program ; no. 29
Title: Choctawhatchee Bay
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00074961/00001
 Material Information
Title: Choctawhatchee Bay analysis and interpretation of baseline environmental data
Series Title: Technical paper Florida Sea Grant College
Physical Description: xxiii, 237 p. : ill. ; 28 cm.
Language: English
Creator: Blaylock, Dewey A
Florida Sea Grant College
Northwest Florida Water Management District (Fla.)
Publisher: Marine Advisory Program, Florida Cooperative Extension Service
Place of Publication: S.l.
Publication Date: [1983]
 Subjects
Subject: Choctawhatchee Bay (Fla.)   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: by Dewey A. Blaylock.
General Note: "March 1983."
General Note: "Co-sponsor for preparation of this document was the Northwest Florida Water Management District."
Funding: This publication is being made available as part of the report series written by the faculty, staff, and students of the Coastal and Oceanographic Program of the Department of Civil and Coastal Engineering.
 Record Information
Bibliographic ID: UF00074961
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 002199017
oclc - 24205701
notis - ALD8897

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Title Page
    Foreword
        Foreword
    Preface
        Preface 1
        Preface 2
    Abstract
        Abstract
    Table of Contents
        Table of Contents 1
        Table of Contents 2
        Table of Contents 3
    List of Figures
        List of Figures 1
        List of Figures 2
        List of Figures 3
        List of Figures 4
        List of Figures 5
        List of Figures 6
    List of Tables
        List of Tables 1
        List of Tables 2
        List of Tables 3
        List of Tables 4
        List of Tables 5
        List of Tables 6
        List of Tables 7
        List of Tables 8
    Acknowledgement
        Acknowledgement
    Introduction
        Page 1
        Page 2
        Page 3
        Physical characteristics
            Page 4
            Page 5
            Page 6
        Economic considerations
            Page 7
            Page 8
            Page 9
            Page 10
            Page 11
            Page 12
            Page 13
    Readers guide
        Page 14
    Conclusions
        Page 15
        Page 16
        Page 17
    Literature synopsis: Physical characteristics
        Page 18
        Climatology
            Page 18
            Page 19
            Page 20
            Page 21
            Page 22
            Page 23
        Hydrology
            Page 24
            Page 25
            Page 26
            Page 27
            Page 23
            Page 28
            Page 29
            Page 30
        Water temperature
            Page 31
            Page 32
            Page 33
            Page 34
            Page 30
        pH
            Page 35
        Salinity
            Page 35
            Page 36
            Page 37
            Page 38
        Dissolved oxygen
            Page 39
            Page 40
            Page 38
            Page 41
    Literature synopsis: Water quality
        Page 42
        Phosphorous
            Page 42
            Page 43
        Nitrogen
            Page 43
            Page 44
            Page 45
        Carbon
            Page 46
            Page 45
        Total and fecal coliform bacteria
            Page 46
            Page 47
            Page 48
    Literature synopsis: Biotic components
        Page 60
        Plankton
            Page 60
            Page 61
            Page 62
        Benthos
            Page 63
            Page 62
        Natural resources
            Page 64
            Page 65
            Page 66
            Page 67
    Literature synopsis: Sediments
        Page 49
        Sediment characterization
            Page 49
            Page 50
            Page 51
            Page 52
        Sediment chemistry
            Page 53
            Page 54
            Page 52
            Page 55
        Metals and pesticides
            Page 56
            Page 57
            Page 58
            Page 59
    Data management and analysis
        Page 85
        Page 86
        Page 87
    Materials, methods and analytical procedures
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
    Results and Discussion: Physical characteristics
        Page 88
        Temperature
            Page 88
            Page 89
            Page 90
            Page 91
            Page 92
            Page 93
            Page 94
            Page 95
            Page 96
        pH
            Page 97
            Page 98
            Page 99
            Page 100
            Page 96
        Salinity
            Page 101
            Page 102
            Page 103
            Page 100
            Page 104
            Page 105
            Page 106
            Page 107
            Page 108
            Page 109
            Page 110
            Page 111
        Dissolved oxygen
            Page 112
            Page 113
            Page 114
            Page 115
            Page 111
    Results and Discussion: Water Quality
        Page 116
        Phosophorous
            Page 116
            Page 117
            Page 118
            Page 119
            Page 120
            Page 121
        Nitrogen
            Page 122
            Page 123
            Page 124
            Page 125
            Page 121
            Page 126
            Page 127
            Page 128
            Page 129
            Page 130
            Page 131
            Page 132
            Page 133
        Carbon
            Page 134
            Page 135
        Total and fecal coliforms
            Page 135
            Page 136
            Page 137
            Page 138
            Page 139
            Page 140
    Sediments
        Page 141
        Sediment characterization
            Page 141
            Page 142
            Page 143
            Page 144
            Page 145
            Page 146
        Sediment chemistry
            Page 147
            Page 148
            Page 149
            Page 146
    Results and Discussion: Biotic components
        Page 150
        Phytoplankton
            Page 150
            Page 151
            Page 152
            Page 153
            Page 154
            Page 155
        Icthyoplankton
            Page 156
            Page 157
            Page 158
            Page 159
            Page 160
        Zooplankton
            Page 161
            Page 162
            Page 163
            Page 164
            Page 165
            Page 166
            Page 167
            Page 168
            Page 169
            Page 170
        Benthos
            Page 171
            Page 172
            Page 173
            Page 174
            Page 175
    References
        Page 176
        Page 177
        Page 178
        Page 179
        Page 180
    Appendix A: Phytoplankton species from Choctawhatchee Bay during the year 1975
        Page 181
        Page 182
        Page 183
        Page 184
        Page 185
    Appendix C: Benthic macrofauna found in Choctawhatchee Bay in 1975
        Page 186
        Page 187
        Page 188
    Appendix D: Significant correlations ( <0.10 ) of monthly water quality parameters with the net discharge of freshwater from the tributaries to Choctawhatchee Bay at each of the 31 water quality stations in 1975
        Page 189
        Page 190
        Page 191
    Appendix E: Significant correlations ( <0.10 ) of water quality parameters with each other at the 31 water quality stations in Choctawhatchee Bay, 1975
        Page 192
        Page 193
        Page 194
        Page 195
        Page 196
        Page 197
        Page 198
        Page 199
    Appendix F: Correlation of Chlorophyllls with water quality parameters of each of the 31 water quality sampling stations in Choctawhatchee Bay, 1975
        Page 200
        Page 201
        Page 202
        Page 203
        Page 204
        Page 205
    Appendix G: Spatial and monthly distribution of phytoplankton in Choctawhatchee Bay, 1975
        Page 206
        Page 207
        Page 208
        Page 209
        Page 210
        Page 211
        Page 212
        Page 213
        Page 214
        Page 215
        Page 216
        Page 217
    Appendix H: Spatial and Monthly distribution of Icthyoplankton in Choctawhatchee Bay, 1975
        Page 218
        Page 219
        Page 220
    Appendix I: Number of zoolplankton/liter found during each month at each station during 1975
        Page 221
        Page 222
        Page 223
        Page 224
        Page 225
        Page 226
        Page 227
        Page 228
        Page 229
        Page 230
        Page 231
    Appendix J: Spatial and monthly distribution of benthic macro invertebrates in Choctawhatchee Bay in 1975
        Page 232
        Page 233
        Page 234
        Page 235
        Page 236
        Page 237
Full Text



Technical Paper No. 29


CHOCTAWHATCHEE BAY:

ANALYSIS AND INTERPRETATION
OF BASELINE ENVIRONMENTAL DATA

Dewev Blavlock


SEA GRANT COLLEI









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Technical Papers are duplicated in limited quantities for specialized
audiences requiring rapid access to information and may receive only limited
editing. This paper was complied by the Florida Sea Grant College with
support from NOAA Office of Sea Grant, U.S. Department of Commerce, grant
number NA80AA-D-00038. It was published by the Marine Advisory Program
which functions as a component of the Florida Cooperative Extension Service,
John T. Woeste, Dean, in conducting Cooperative Extension work in Agri-
culture, Home Economics, and Marine Sciences, State of Florida, U.S.
Department of Agriculture, U.S. Department of Commerce, and Boards of
County Commissioners, cooperating. Printed and distributed in furtherance
of the Acts of Congress of May 8 and June 14, 1914. The Florida Sea Grant
College is an Equal Employment Opportunity-Affirmative Action employer
authorized to provide research, educational information and other services
only to individuals and institutions that function without regard to race,
color, sex, or national origin.


.1


CHOCTAWHATCHEE BAY: ANALYSIS AND

INTERPRETATION OF BASELINE

ENVIRONMENTAL DATA

By

Dewey A. Blaylock

Technical Paper No. 29
March 1983






Institute for Statistical and Mathematical Modeling
University of West Florida
Pensacola, Florida 32504

Co-Sponsor for preparation of this document
was the Northwest Florida Water Management District.















FOREWORD


Choctawhatchee Bay, with its 86,295 acres of surface area and 1,521,106

acre-feet of water, comprises the third largest estuarine system on the Gulf

Coast of Florida. As human activities encroach on the natural ecology of th

Bay, its natural equilibrium will be altered. We can have a positive

influence on these changes through a greater understanding of the dynamics o

the ecosystem of the Bay. The future use and exploitation of the Bay must b

carefully planned, and effective planning can result only from detailed

knowledge of the biology, water chemistry, physiography, sediments and the

general health of the ecosystem.




1









PREFACE


The final objective of any environmental study of this scope is to provide

the insight that natural resource managers require to develop an appropriate

management program. A comprehensive resource management program should pre-

cede all future decisions which affect Choctawhatchee Bay and point the direc-

tion to initiation of further studies. Delineation of guidelines, within a

resource management program, requires a comprehensive data base and report

concerning the dynamics of the Bay ecosystem and the components of the current

and previous state of the Bay. Initial objectives in this process are to pro-

vide a concise summary of historical technical data and information which

exist concerning Choctawhatchee Bay. This report attempts to integrate both

historical and current environmental knowledge to provide a basic

understanding of Choctawhatchee Bay to planners involved with implementing a

much needed Bay management strategy.

Among the bays and estuaries of the Florida Panhandle Region,

Choctawhatchee Bay is one of the most sparsely documented in terms of dynamics

and ecology. In a first effort toward gaining insight on the nature of the

Bay, all available technical and historical information and data sources were

compiled. Presently, all of the sources of information concerning

Choctawhatchee Bay are maintained at the Northwest Florida Water Management

District. Reduction of the literature to pertinent information sources was

greatly facilitated by a comprehensive summary of all known literature con-

cerning the environment of Choctawhatchee Bay (Northwest Florida Water


iii









Management District, 1980). The pertinent literature was reviewed and infor

mation concerning each environmental character represented in these historic

and technical documents are presented and discussed. Of primary concern are

temporal and spacial differences in the Bay as well as the quality and

accuracy of the source.

The second phase of this report is concerned with the presentation of da

gathered during the 1975 Florida Sea Grant sponsored project R/EM-5 (Collard

1976). This grant was carried on through the University of West Florida,

Department of Biology under the direction of Sneed B. Collard. It was pri-

marily concerned with a biophysical environmental inventory of Choctawhatche

Bay over both seasonal and quarterly diurnal time frames. After the data we

computerized they were visually checked for accuracy and summarized over tin

and space using tabular output and graphics including maps, contours, time

plots and profiles. In order to grasp the interrelationships, and in turn t

dynamics of the Bay, a host of statistical techniques including correlations

regressions, non-parametrics and cluster analyses were employed. Finally, t

data were stored as a computerized data base at the Northeastern Regional Dz

Center (NERDC) in Gainesville, Florida, for future use by concerned groups

desiring to study Choctawhatchee Bay (Blaylock, 1982).















ABSTRACT


This report characterizes the environmental conditions and mechanisms pre-

sent in Choctawhatchee Bay. Existing environmental conditions documented in

literature are summarized and discussed. Biological, physical and chemical

data collected by the University of West Florida in 1975, through Florida Sea

Grant Funding are analyzed and presented. Finally, the summarized literature

and the 1975, University of West Florida study are assimilated into a detailed

characterization of the ecosystem of Choctawhatchee Bay.

Intensive literature surveys were conducted for documents concerning both

historical and current information on environmental conditions in Choctawhatchee

Bay. Much of the survey was done by the Northwest Florida Water Management

District, who also maintains a complete library of literature concerning

Choctawhatchee Bay. The information in these documents was reviewed, con-

densed and discussed as an introductory characterization.

The University of West Florida conducted an intensive monthly survey of

environmental conditions in Choctawhatchee Bay for thirty-one stations during the

year 1975. Also, diurnal 48 hour studies were conducted at eight stations for

each of the four seasons. Data collected includes phytoplankton, zooplankton,

coliform bacteria, benthos, fish, nutrients and physical information. This infor-

mation was computerized and reviewed using graphic and statistical techniques.

Finally, information from both documented sources and the University of

West Florida data analysis were integrated and general conclusions describing

the conditions of the Bay were presented.
















CONTENTS
Pac

Foreword .......................................... ................... .

Preface .......... .......................... .............. i

Abstract .........................................................

List of Figures ........... ................................ .......... j

List of Tables ..................................... ................. .

List of Appendices .................................................... xi

List of Supplemental Appendices ........................... ......

Acknowledgment ........................................................ xxij

1. Introduction ..................................................

A. Physical Characteristics ..................................

B. Economic Considerations ..................................

2. Readers Guide ................................................

3. Conclusions ................................................

4. Literature Synopsis ...........................................

A. Physical Characteristics ................................

Climatology ...........................................

Hydrology .. ........................................

Water Temperature .....................................

pH ................................ .............

Salinity ........................... .... .......... ....

Dissolved Oxygen .....................................















TABLE OF CONTENTS (continued)
Page

B. Water Quality ............................................. 42

Phosphorous ........................................... 42

Nitrogen ..................................... .. .. 43

Carbon ............................................... 45

Total and Fecal Coliform Bacteria ..................... 46

C. Sediments .................................................. 49

Sediment Characterization ............................ 49

Sediment Chemistry .................................. 52

Metals and Pesticides ............................... 56

D. Biotic Components .................................... ..... 60

Plankton ............................................. 60

Benthos ........................................ .... 62

Natural Resources ........................ ........ 64

5. Materials, Methods and Analytical Procedures .................. 68

General ............................................. 68

Monthly Sampling ..................................... 68

Physical Parameters ................................. 71

Water Chemistry ...................................... 75

Biological Parameters ................................ 75

Quarterly Diurnal Studies ............................ 77

Sediment Analysis .................................... 80

6. Data Management and Analysis ................................. 85
















TABLE OF CONTENTS (continued)
Pag

7. Results and Discussion ......................................... 8

A. Physical Characteristics ................................... 8

Temperature .............................................

pH ............ ..... ... ...... ... ... .... ....... .. S

Salinity ............... ........... ................ .... 1C

Dissolved Oxygen ....................................... 11

B. Water Quality .............................................. 11

Phosphorous .................................. ... .... 11

Nitrogen ............................................. 1

Carbon ................................................

Total and Fecal Coliforms ............................. 1

C. Sediments .................................................. 1V

Characterization .............. ......................... 11

Chemistry .............................................. 1

D. Biotic Components .......................................... 11

Phytoplankton .............. ................. 1.

Icthyoplankton ........ .. ....... ..................... 1!

Zooplankton ............................................ 1I

Benthos ..................................... 1

References ....... ...................... ...... ......... ...... 1


viii















LIST OF FIGURES


Number Page

1-1 Map of Choctawhatchee Bay ................................... 2

1-2 Map of the Northwest Florida Panhandle ....................... 3

3-1 Box Model Depicting Nutrient Flux in Choctawhatchee Bay ....... 17

4-1 Daily Air Temperature During 1975 at Eglin Air Force
Base, Florida ................................................. 19

4-2 Average Monthly Air Temperatures from 1970 to 1975 at
Eglin Air Force Base, Florida ...... .................. 19

4-3 Daily Precipitation during 1975 at Eglin Air Force
Base, Florida ............................................. 21

4-4 Average Monthly Precipitation from 1970 to 1975
Eglin Air Force Base, Florida ........................... 21

4-5 Annual Precipitation from 1971 to 1975 at Eglin Air
Force Base, Florida ...................................... 22

4-6 Cloud Cover Percentages for the year 1975, at
Eglin Air Force Base, Florida ............................. 22

4-7 Wind Direction Percentages for the year, 1975, at
Eglin Air Force Base, Florida ............................. 24

4-8 Average Annual Air Temperature for the year 1975,
at Eglin Air Force Base, Florida .......................... 24

4-9 Station Depths in Choctawhatchee Bay .......................... 25

4-10 Foraminiferal Distribution Choctawhatchee Bay
Sediments ........................ ...... ............. 28

4-11 Silt Laden Freshwater Entering Choctawhatchee Bay
during a March, 1975 Storm ............................... 29

4-12 Average Annual Discharge from Juniper Creek near
State Road 85, Niceville, Florida from
1968-1978 ..................... ........................... 31

ix
















LIST OF FIGURES (continued)


Number Pag(

4-13 Average Annual Discharge from Alaqua Creek near
DeFuniak Springs, Florida from 1968-1978 ................ 3'

4-14 Average Annual Discharge from Magnolia Creek
near Freeport, Florida from 1968-1978 .................... 3;

4-15 Average Annual Discharge from Choctawhatchee River
near Bruce, Florida from 1968-1978 ...................... 3;

4-16 Mean Monthly Discharge from Choctawhatchee River
near Bruce, Florida in the year 1975 ...................... 3:

4-17 Mean Monthly Discharge from Magnolia Creek near
Freeport, Florida for the year 1975 ....................... 3]

4-18 Mean Monthly Discharge from Alaqua Creek near
DeFuniak Springs, Florida for the year 1975 .............. 34

4-19 Mean Monthly Discharge from juniper Creek near
State Road 85, Niceville, Florida for the
year 1975 .................................................. 34

4-20 Point Source Inputs, Submerged Grass Beds, and
Major Fishing Grounds in Choctawhatchee Bay
(in part from McNulty) .... .............................. 4

4-21 Bottom Types in Choctawhatchee Bay ........................... 5.

4-22 Map Depicting Oyster Beds and Areas Closed to
Shellfishing in 1970 ...................................... 6.

5-1 Monthly Sampling Stations in Choctawhatchee Bay,
1975 .......................................... .......... 65

5-2 Location of Biotic Sampling Stations in
Choctawhatchee Bay, 1975 ................................. 7L

5-3 Locations of the Eight Stations Sampled During
the Quarterly Diurnal Studies in Choctawhatchee
Bay, 1975 .................. ....... ...................... 75















LIST OF FIGURES (continued)


Number Page

5-4 Location of Sediment Samples Collected in
Choctawhatchee Bay in 1974 by the U.S.
Environmental Protection Agency, 1975 ..................... 83

7-1 Water Temperature at Station Seventeen in
Choctawhatchee Bay during the year 1975 ................... 90

7-2 Water Temperature at Station Twenty-three in
Choctawhatchee Bay during the year 1975 ................... 90

7-3 Average Monthly Water Temperature for
Choctawhatchee Bay during the year 1975 ................... 91

7-4 Average Monthly Surface Water Temperature for
Choctawhatchee Bay during the year 1975 ................. 91

7-5 Depth Profiles of Temperature, Salinity, pH, and
to Dissolved Oxygen in May at Each of the Eight
7-12 Quarterly Stations ......................................92-95

7-13 Zone of Maximum Turbidity. Arrows indicate where
mixing occurs and sediments are trapped .................. 104

7-14 Tidal Inflow into Choctawhatchee Bay ......................... 104

7-15 Salinity in the Bottom of Choctawhatchee Bay
on December 15, 1975 .................................... 110

7-16 Dissolved Oxygen at Station Thirteen in
Choctawhatchee Bay during the year 1975 ................. 114

7-17 Dissolved Oxygen at Station Seventeen in
Choctawhatchee Bay during the year 1975 ................... 115

7-18 Dissolved Oxygen at Station Eighteen in
Choctawhatchee Bay during the year 1975 .................. 116

7-19 Dissolved Oxygen at Station Twenty-five in
Choctawhatchee Bay during the year 1975 ................... 117















LIST OF FIGURES (continued)


Number Pagt

7-20 Annual Trend of Total Phosphorous in Choctawhatchee
Bay, 1975 ..................... .. ............ .......... 12(

7-21 Annual Trend of Dissolved Phosphorous in
Choctawhatchee Bay, 1975 ................................. 12(

7-22 Ammonia Concentration at Station Three in
Choctawhatchee Bay during the year 1975 ................... 12(

7-23 Ammonia Concentration at Station Four in
Choctawhatchee Bay during the year 1975 ................. 12(

7-24 Ammonia Concentration at Station Seventeen in
Choctawhatchee Bay during the year 1975 ................... 121

7-25 Ammonia Concentration at Station Twenty in
Choctawhatchee Bay during the year 1975 ................... 121

7-26 Ammonia Concentration at Station Twenty-one
in Choctawhatchee Bay during,the year 1975 ................ 121

7-27 Annual Trend of Ammonia for Choctawhatchee Bay
during the year 1975 ...................................... 121

7-28 Annual Trend of Ammonia in Bottom Waters for
Choctawhatchee Bay during the year 1975 ................... 121

7-29 Nitrate-Nitrite Concentration at Station
Seventeen in Choctawhatchee Bay during the
year 1975 ........................................... ..... 131

7-30 Nitrate-Nitrite Concentration at Station
Twenty-two in Choctawhatchee Bay during the
year 1975 ................................................ 131

7-31 Annual Trend of Nitrate-Nitrite for Choctawhatchee
Bay during the year 1975 ................................ 131

7-32 Annual Trend of Total Carbon for Choctawhatchee Bay
during the year 1975 ..................................... 13















LIST OF FIGURES (continued)


Number Page

7-33 Annual Trend of Total Organic Carbon for
Choctawhatchee Bay during the year 1975 ................... 137

7-34 Annual Trend of Total and Fecal Coliform Bacteria
for Choctawhatchee Bay during the year 1975 ............. 140

7-35 The Percent Sand in the Sediments in Choctawhatchee
Bay, November 25, 1975 ................................... 142

7-36 The Percent Clay in the Sediments in Choctawhatchee
Bay, November 25, 1975 ......... ............. ..... ...... ... 143

7-37 The Percent Silt in the Sediments in Choctawhatchee
Bay, November 25, 1975 .................................. 144

7-38 The Clay/Silt Ratio in the Sediments in Choctawhatchee
Bay, November 25, 1975 ................................... 145

7-39 The Percent Organics in the Sediments in Choctawhatchee
Bay, November 25, 1975 .................................... 147

7-40 Total Kjeldahls Nitrogen in the Sediments in
Choctawhatchee Bay, November 25, 1975 .................. 148

7-41 Total Phosphorous in the Sediment in Choctawhatchee
Bay, November 25, 1975 ...................................... 149

7-42 Annual Trend of Total Chlorophyll for.Choctawhatchee
Bay during the year 1975 ..... ....... ... .................. 151

7-43 Annual Trend of Total Numbers of Phytoplankton for
Choctawhatchee Bay during the year 1975 .................. 154

7-44 Annual Trend of Diatom Dinoflagellate and Micro-
Algae Biomags for Choctawhatchee Bay during
the year 1975 .......................................... 154

7-45 Annual Trend of Fish Eggs found in Choctawhatchee Bay
during the year 1975 ................................... 158


xiii















LIST OF FIGURES (continued)


Number Page

7-46 Annual Abundance of Fish Eggs at Choctawhatchee Bay
sampling stations in 1975 .................................... 15

7-47 Annual Trends of Total Fish Larvae, Menidia sp. larvae
and Anchoa sp. larvae in Choctawhatchee Bay in
1975 ...................................... .............. 164

7-48 Annual Abundance of Fish Larvae from Choctawhatchee
Bay Sampling Stations in 1975 ............................ 161















LIST OF TABLES


Number Page

1-1 Waterborn Commerce through the Gulf Intracoastal
Waterway from Panama City, Florida to
Pensacola, Florida (110 miles) ............................ 9

1-2 Waterborn Commerce in LaGrange Bayou ......................... 10

1-3 Waterborn Commerce through East Pass .......................... 11

1-4 The Amount and Value at Commerical Marine
Invertebrates Taken from Choctawhatchee Bay,
Florida ................................................... 12

1-5 Average Annual Seafood Catch for Choctawhatchee Bay ........... 13

4-1 Total Phosphorous, Organic Nitrogen and Organic
Carbon in Mud Sediment Samples from five
Northwest Florida Bays ................................. 53

4-2 Percent of Mud in Sediments from Central Basins of
Six Northwest Florida Bays ................................ 55

4-3 Mean Concentrations of Metals in Surface Sediments
of Selected Days in Northwest Florida ..................... 58

5-1 Monthly Sampling Schedule for the Sea Grant sponsored
University of West Florida study of Choctawhatchee
Bay, Florida ....................................... ... 70

5-2 Weather Conditions for the Five Days Prior to Each
Sampling Period ........................................... 72

5-3 Physical, Chemical and Biological Parameters sampled
Monthly in Choctawhatchee Bay, 1975 ....................... 73

5-4 Quarterly Sampling Schedule for the Sea Grant sponsored
University of West Florida study of Choctawhatchee
Bay, Florida ............................................ 78

5-5 Mean Weather Conditions for the Five Days Prior to
Each Quarterly Sampling Period ............................ 81


xv
















LIST OF TABLES (continued)


Number Pag,

5-6 U.S. Geological Society Flow Gages on Tributaries
to the Choctawhatchee Bay ................................ 8.

7-1 Annual Means of Physical Parameters for Choctawhatchee
Bay and for each Individual Sampling Depth during
1975 ................... ..... ........ .............. ..... 8

7-2 Significant Regressions Between Water Quality Parameters
and Benthic Water Column Coliform Bacteria ................ 9

7-3 Significant Regressions Between Water Quality Parameters
and Surface Water Column Bacteria ........................ 9

7-4 Significant Correlations Between Temperature and other
Water Quality Parameters across the Bay and for
each depth across the Bay ................................. 9

7-5 Quarterly Diurnal pH Averages and Overall pH Averages
in Choctawhatchee Bay, 1975 ............................... 10

7-6 Statistically Significant Correlations of Freshwater
discharge into Choctawhatchee Bay with salinity
and dissolved oxygen, 1975 ............................... 10

7-7 Mean Salinities at the Surface, Mid-depth and Bottom
for Stations 23, 24 and 25 .............................. 10

7-8 Mean Salinities at the Surface, Mid-depth and Bottom
for Stations 15, 16, 17, 18, 19, 21 and 22 ................ 10

7-9 Statistically Significant (a = 0.10) Stepwise
Regressions Depicting the Relationship Between
Nutrients and Total Chlorophyll ......................... 1C

7-10 Annual Means for Water Quality Parameters including
dissolved phosphorous, total phosphorous, total
carbon and total organic carbon for Choctawhatchee
Bay and for each sampling depth during 1975 ............. 11















LIST OF TABLES (continued)


Number Page

7-11 Significant Correlations of Water Quality Parameters
with Total Phosphorous across Choctawhatchee Bay
at the Surface, Mid-depth andBottom ...................... 119

7-12 Significant Correlations of Water Quality Parameters
with Dissolved Phosphorous across Choctawhatchee
Bay at the Surface, Mid-depth and Bottom .................. 122

7-13 Annual Means of Water Quality Parameters including
Ammonia, Nitrate and Kjedahls Nitrogen for
Choctawhatchee Bay and for each sampling
depth during 1975 ............................. ........ 125

7-14 Significant Correlations Between Ammonia and Water
Quality Parameters across Choctawhatchee Bay at
the Surface, Mid-depth and Bottom ......................... 132

7-15 Significant Correlations Between Nitrate-Nitrite
and Water Quality Parameters across Choctawhatchee
Bay at the Surface, Mid-depth and Bottom .................. 133

7-16 Significant Correlations Between Total Carbon and
Total Organic Carbonl across Choctawhatchee Bay
at the Surface, Mid-depth and Bottom ..................... 136

7-17 Annual Means of Total and Fecal Coliform Bacteria
for Choctawhatchee Bay and for each sample
depth during 1975 ................................... ..... 138

7-18 Annual Means of Total Chlorophyll, Chlorophyll A,
Chlorophyll B, and Chlorophyll C for
Choctawhatchee Bay and for each sample depth
during 1975 ............... ......................... 152

7-19 Annual totals of Fish Larva Found in Choctawhatchee
Bay in 1975 ........................................... 157

7-20 Species of Fish Larvae found in Choctawhatchee Bay
in 1975 at sample stations ................................ 159


xvii















LIST OF TABLES (continued)


Number Pa(

7-21 Annual Average Numbers of the Major Species of
Zooplankton collected at each station in
Choctawhatchee Bay in the year 1975 ...................... 1

7-22 Monthly Average Numbers of the Major Species of
Zooplankton collected in Choctawhatchee Bay
in the year 1975 ......................................... 1i

7-23 Annual Average Numbers of the Major Groups of
Zooplankton collected at each station in
Choctawhatchee Bay in the year 1975 ....................... 1(

7-24 Monthly Average Numbers of the Major Groups of
Zooplankton collected in Choctawhatchee Bay
in the year 1975 ................... ....... ........ ... 1i

7-25 Annual Average Numbers of the Larval Zooplankton
collected at each station in Choctawhatchee Bay
in the year 1975 ................. ......................... 1I

7-26 Monthly Average Numbers of the Larval Zooplankton
collected in 'Choctawhatchee Bay in the
year 1975 .............................................. 1I

7-27 Annual Average Numbers of Cladoceran genera collected
at each station in Choctawhatchee Bay in the
year 1975 ...... .............. ..... .......................

7-28 Monthly Average Numbers of Cladoceran genera collected
in Choctawhatchee Bay in the yer 1975 ..................... 17

7-29 Correlations of Numbers of Benthic Macroinvertebrates
with Benthic Sediment Parameters across
Choctawhatchee Bay Quarterly Sampling Stations ............ 1i

7-30 Annual Total Numbers of Benthic Macroinvertebrates
collected at the Eight Quarterly sampling stations
in the year 1975 ........................................ 17


xviii















APPENDICES


Page


Appendix

A


B


C


D




E



F



G


H


I


3


xix


Phytoplankton Species from Choctawhatchee Bay
in the year 1975 ...................................

Zooplankton Found in Choctawhatchee Bay in
the year 1975 ...................... ........ ........

Benthic Macrofauna found in Choctawhatchee Bay
in the year 1975 ....................................

Correlations of Monthly Water Quality Parameters
with the Net Inflow into Choctawhatchee Bay
in 1975 at each of the Thirty-one Quality
Sampling Stations ....................................

Correlations of Water Quality Parameters at
each of the Thirty-one Water Quality
Sampling Stations ....................................

Correlations of Chlorophylls with Water Quality
Parameters at each of the Thirty-one Quality
Sampling Stations ................... ..................

Spacial and Monthly Distributions of Phytoplankton
in Choctawhatchee Bay, 1975 .........................

Spacial and Monthly Distributions of Ichthyoplankton
in Choctawhatchee Bay, 1975 ...........................

Numbers of Zooplankton found during each Month at
each Station in 1975 .................................

Spacial and Monthly Distributions of Benthic
Macro Invertebrates in Choctawhatchee Bay in
1975 .................................... .........















Unattached Supplemental Appendices


Number Page

A Salinity, Temperature, pH and Dissolved Oxygen
Profiles for Quarter One, Stations One
Through Eight ...................................... A1-A41

B Salinity, Temperature, pH and Dissolved Oxygen
Profiles for Quarter Two, Stations One
Through Eight .................................... B1-B65

C Salinity, Temperature, pH and Dissolved Oxygen
Profiles for Quarter Three, Stations One
Through Eight ............... ................... C1-C64

D Salinity, Temperature, pH and Dissolved Oxygen
Profiles for Quarter Four, Stations One
Through Eight ...................................... D1-D64

E Map of Salinity Concentrations for each Sample
Depth and for each Month in 1975 ................... E1-E30

F Annual Trend for Salinity at each Depth for each
Station .......................................... F1-F31

G Map of Temperature for each Sample Depth and for
each Month in 1975 ................................. G1-G30

H Annual Trend for Temperature at each Depth for
each Station ....................................... H1-H31

I Map of Dissolved Oxygen Concentrations for each
Sample Depth and for each Month in 1975 ........... 11-130

3 Annual Trend for Dissolved Oxygen at each Depth
for each Station ................................... 31-331

K Map of Ammonia Concentrations for each Sample
Depth and for each Month in 1975 ................... K1-K30

L Annual Trend for Ammonia at each Depth for each
Station .................................... ..... L1-L31


xx















Unattached Supplemental Appendices (continued)


Number Page

M Map of Nitrate-Nitrite Concentrations for each
Sample Depth and for each Month in 1975 ............ M1-M30

N Annual Trend for Nitrate-Nitrite at each Depth
for each Station ................................. N1-N31

0 Map of Organic Nitrogen Concentrations for each
Sample Depth and for each Month in-1975 .......... 01-030

P Annual Trend for Organic Nitrogen at each
Depth for each Station ............................. P1-P31

Q Map of Total Phosphorous Concentrations for each
Sample Depth and for each Month in 1975 ............ 01-Q30

R Annual Trend for Total Phosphorous at each
Depth for each Station .................... ........ R1-R31

S Map of Dissolved Phosphorous Concentrations for
each Sample Depth and for each Month in 1975 ....... S1-S30

T Annual Trend for Dissolved Phosphorous at each
Depth for each Station ............................ T1-T31

U Map of Total Carbon Concentrations for each
Sample Depth and for each Month in 1975 ............ U1-U30

V Annual Trend for Total Carbon at.each Depth
for each Station ................................. V1-V31

W Map of Organic Carbon Concentrations for each
Sample Depth and for each Month in 1975 ............ W1-W30

X Annual Trend for Organic Carbon at each Depth
for each Station ................................. X1-X31

Y Map of Total Coliform Bacteria Numbers for
each Sample Depth and for each Month in 1975 ....... Y1-Y20



xxi





i
















Unattached Supplemental Appendices (continued)


Number Page

Z Annual Trend for Total Coliform Bacteria at each
Depth for each Station ............................. Z1-Z10

AA Map of Fecal Coliform Bacteria Numbers for each
Sample Depth and for each Month in 1975 ............AA1-AA2

BB Annual Trend for Fecal Coliform Bacteria at
each Depth for each Station ........................BB1-BB1

CC Map of Total Chlorophyll Concentrations for
each Sample Depth and for each Month in 1975 .......CC1-CC1

DD Phytoplankton Numbers by Species, Stations and
Months in Choctawhatchee Bay, 1975 ................DD1-DD6


xxii




I1


Acknowledgment


The author is grateful to many individuals who contributed to the develop-

ment of this comprehensive report on the ecology of Choctawhatchee Bay.

Sneed B. Collard was instrumental in initiation of the project and must also

be thanked for allowing the use of the data collected in Choctawhatchee Bay in

1975 by the Department of Biology, University of West Florida. Charles T.

Gaetz assisted with computerized data presentation and graphics. The staff at

the Northwest Florida Water Management District provided constructive '

editorial comments throughout the project. Anne Howick provided typing and

editorial assistance for the final report.


xxiii















1 INTRODUCTION


Choctawhatchee Bay is located in the Panhandle Region of Northwest Florida

with the longitudinal axis in an east-west orientation (Figure 1-2). The

primary tributary to the Bay is the Choctawhatchee River at the eastern end of

the Bay, while East Pass is the only direct outlet to the Gulf of Mexico, and

is located near the west end of the Bay at Destin, Florida (Figure 1-1).

Santa Rosa Sound opens into Choctawhatchee Bay in the vicinity of Fort Walton

Beach and is an indirect passage to the Gulf of Mexico through Pensacola Bay

approximately 40 miles to the west (Figure 1-2). The largest municipality,

Fort Walton Beach, is located around Santa Rosa Sound and the deeper bayous at

the western end of the Bay. From 1954 to 1974 Fort Walton Beach and nearby

municipalities experienced a 700 percent increase in population (Nix, 1976)

and the rate is expected to continue, since large amounts of land around the

Bay have been purchased for residential development. This will add to the

sewage and storm water input to the Bay, particularly around the many adjacent

bayous where most of the development is centered. Some of these bayous are

already sites of degradation problems, and continued increases to the nutrient

loading to these bayous through point source, and nonpoint source input only

exacerbate the problems in these specific bayous (Ross, Anderson and Jenkins,

1974).






1






































Niceville


Bayou


U Garnier


SANTA ROSA


NAUTICAL MILES
1 --- --- -
YARDSwhathee Bay.




Figure 1-1: Map of Choctawhatchee Bay.





















ALABAMA


Figure 1-2: Map of the Northwest Florida Panhandle.


ALABAMA


GEORGIA















PHYSICAL CHARACTERISTICS


Choctawhatchee Bay has a surface area of 86,295 acres and is the third

largest estuarine system on the Gulf Coast of Florida. Only Tampa Bay and

Charlotte Harbor are larger (McNulty, Lindall and Sykes, 1972). The Bay is

approximately 29.2 miles from east to west and about 3 miles wide at its

widest point. A maximum depth of 43 feet may be found in the Bay just north

of East Pass. Tidal range inside Choctawhatchee Bay varies from .6 feet in

the eastern bay to 1.4 feet in Santa Rosa Sound (U.S. Army Corps of Engineer

1976). Outside East Pass, the tidal range averages 1.5 feet (U.S. Army Corp

of Engineers, 1976). The low tidal range in eastern Choctawhatchee Bay as

compared to the western end of the Bay and other bays in Northwest Florida,

including St. Andrews Bay and Escambia Bay with tidal ranges of 1.5 feet, me

be attributed to many factors. These include the size of Choctawhatchee Bay

the shallowness of East Pass, the inflow volume and proximity of Choctawhatc

River, and Santa Rosa Sound, an indirect outlet to the Gulf of Mexico.

The entrainment of Choctawhatchee Bay occurred at approximately 3000 B.P

when a sea level change formed Moreno Point (Goldsmith, 1966, Pastula, 1967)

This formation eventually led to the creation of a bay of brackish nature,

which supported estuarine shellfish including oysters, which occurred in

archeological digs in large numbers between the ages of 3135 B.P. to about 6

B.P. (Fairbanks, 1960). Choctawhatchee Bay, in the early 1900's was an

inland, slightly brackish, body of water with minimal saltwater intrusion an








mixing (Okaloosa Economic Development Council (OEDP), 1978. During flood

conditions the freshwater inflow often exceeded the drainage rate through the

former pass which was part of Destin's Old Pass Lagoon. In the late twenties,

during flood conditions, a trench was dug at the site of East Pass and the

rapid flow of water from the Bay to the Gulf of Mexico rapidly washed out a

wide pass (OEDP, 1978). The Corps of Engineers periodically dredged that

pass to prevent natural shoaling (U.S. Army Corps of Engineers, 1975).

Choctawhatchee Bay is fed through 13 major inflow points with the

Choctawhatchee River accounting for more than 95% of the flow. Choctawhatchee

River is the fourth largest river in Florida, draining about 4,000 square

miles in lower Alabama and the Florida Panhandle. The main tributaries are

Pea River in Alabama and Holmes Creek in Florida. The annual flow rates in

Choctawhatchee River average from 5,500 cfsd in late summer to a maximum of

28,000 cfsd in early spring. The effect of the tributaries on the Bay can be

determined by measuring the loading rates of nutrients, sediments and toxics.

This rate is the total volume of a particular item contained in the inflow

being deposited into the reaches of the Bay. The minor tributaries to

Choctawhatchee Bay flow into the fringing bayous, and these bayous receive

initial loading of nutrients and runoff wastes from these tributaries.

For this reason, long term effects on the Bay due to a given set of

circumstances may be observed more rapidly within the bayous. In order to

measure effects within the bayous, their physiography must be studied to assess

the final effects on the Bay. In the Choctawhatchee River drainage basin, the

eastern bayous are generally shallow and must be dredged to allow moderate

boat traffic (U.S. Army Corps of Engineers, 1973). The western bayous,

including those located west of Niceville (Figure, 1-1), are deep and may act




5









as sediment traps for their respective tributaries. Garnier Bayou in

Shalimar, Florida, was suspected to once have have been a river channel.














ECONOMIC CONSIDERATIONS


Historically, Choctawhatchee Bay has been widely recognized for its

recreational, transportational and commercial fishing importance. The Bay

also serves as an important nursery and/or breeding ground to commercial and

sport fishing species.

The recreational potential of the Bay has stimulated localized growth and

promoted tourism. The quiet bayous of the Bay are used extensively for

swimming, water-skiing, sailing and fishing, while the open waters of the main

Bay are suited for large pleasure craft. Sportfishing interests in the Bay

include trolling for spanish mackerel and bluefish, shrimping, cast fishing

for seatrout, croaker and other sport fish and oystering. These recreational

interests, as well as aesthetic appeal, have led to a boom in residential and

commercial development around the Bay (Hennington, Durham and Richardson,

1976; West Florida Regional Planning Council, 1976). In 1975, the growth of

the three western counties adjacent to Choctawhatchee Bay was second in

Florida only to the Tampa-St. Petersburg area. Secondly, and possibly of

greater importance to the economy, is the support the Bay lends in promotion

of tourism. Tourism contributes significantly to retail sales which is second

only to military spending as a revenue source for Okaloosa County (Post,

Buckley, Schuh and Jernigan, 1977).

A portion of the U.S. Intercoastal Waterway passes through the length of

Choctawhatchee Bay connecting it with Pensacola Bay in the west through Santa









Rosa Sound, and to West Bay in the east. An average of 4,381,234 tons of

shipping passed between these points from 1970 to 1974 (Table 1-1).

Maintenance dredging is performed by the Corps of Engineers to prevent

shoaling of the Intracoastal Canal channel through deposition of sediments

from Choctawhatchee River. In Walton County a minor seaport is maintained a

Freeport, Florida, by the Corps of Engineers on LaGrange Bayou. The average

annual tonnage of shipping moving through LaGrange Bayou from 1970 to 1974 w

202,764 tons. Gasoline was the principal import, while agricultural

products, fertilizers, sand and gravel were the primary exports. Tables 1-1

1-2 and 1-3 represent vessel trips, passengers and shipping tonnages for Eas

Pass, LaGrange Bayou, and the Intracoastal waterway from Pensacola to Panama

City, Florida.

Choctawhatchee Bay and adjacent Gulf of Mexico waters are widely

recognized for both recreational and commercial fishing importance. Sport

fishing in Choctawhatchee Bay accounts for 19.5 percent of the local sport

fishing effort, while commercial Bay fishermen are responsible for only 12.7

percent of the total local commercial harvest (Irby, 1974). Irby, 1974,

reports some 41,971 sport fishermen spending 104,004 man-hours of effort in

the Bay, accounting for 16.4 percent of the total sport fishing harvest over

13.5 month period. A federal fishery management program for striped bass

(Morone saxatilis) was established in 1968, but was discontinued due to lack

funding (Northwest Florida Water Management District, 1980). A number of

commercial oystering interests have been developed in Choctawhatchee Bay as

described by Ritchie, 1961. But, as he points out, any further development

should follow a detailed seasonal study of hydrographic conditions.


I---------------------____ ______________ ^ _














Table 1-1:


Waterborn Commerce through the Gulf Intracoastal Waterway from

Panama City, Florida to Pensacola, Florida (110 miles).


Tons Shipping

4193132

4630497

4469075

4427047

4186422


Number of Vessel Trips

7978

7861

7839

7787

7371


Source: Waterborn Commerce of the United States, 1970-1974.


Year

1970

1971

1972

1973

1974















Table 1-2: Waterborn Commerce through LaGrange Bayou


Tons Shipping

164565

234348

197828

236696

1803852


Number of Vessel Trips

461

255

279

316

252


Source: Waterborn Commerce of the United States, 1970-1974.


Year

1970

1971

1972

1973

1974















Table 1-3: Waterborn Commerce through the East Pass


Tons Shipping

3324

332

486

2473


Passengers

61392

79962

100464

91104


Number of Vessel Trips

4742

5616

8184

7288


Source: Waterborn Commerce of the United States, 1970-1974.


Year

1970

1971

1972

1973
















Table 1-4: The Amount and Value of Commercial Marine Invertebrates

Taken from Choctawhatchee Bay, Florida

(Source: National Marine Fisheries Service, New Orleans)


Blue Crab


Shrimp


Spring Oysters


1966

Pounds
Dollars


4,300
1,200


158,500
83,761


4,300


Fall Oysters


Squid


2,500


400


153



193


1967

Pounds
Dollars


50,400
2,671


122,600
63,247


5,200
2,260


1,400



2,400


1968

Pounds
Dollars


220,300
14,914


106,200
60,261


4,600
1,967


2,700
1,155


3,700


1969

Pounds
Dollars


1970

Pounds
Dollar


233,400 15,200
17,822 1,39


41,500 72,900
21,156 32,08


9,700
4,203


3,800
1,646


700


10,900
5,29


1,300


1,500


L~llll~l~L-----~--~-llll~













Table 1-5:


Average Annual Seafood Catch for Choctawhatchee Bay


Catch Per Acre (pounds)


Area (acres)


86,295


Finfish


Shellfish


Total


8.2


Source: National Marine Fisheries Service, Monthly Reports.















2 READERS GUIDE


The document culminates much time and effort by students and faculty oi

the University of West Florida. It is hoped that it will be useful in

decisions made concerning Choctawhatchee Bay. I hope that the decisions at

made with the thought that environmental changes in most cases occur very

slowly and that it takes many years to correct mistakes.

Section Four is a complete literature review with detailed discussions

the processes and properties which affect the ecology of an estuary. This

section is most useful for persons interested in a detailed history of the

ecological studies in Choctawhatchee Bay. It covers each aspect of the

estuary as well as a discussion of information necessary to explain the

results of this study. Section Seven contains the results of this study all

with explanations of the processes in the Bay. As in Section Four the

parameters are discussed individually. In addition to the Appendices shown
*
here a complete supplemental Appendix of all results is available.


NOTE: The Supplemental Appendices (p.xx) contain 965 pages, and are not inclu
with this document. Also not included is an additional Supplemental Appendix,
to the Fishes of Choctawhatchee Bay and Other Northern Gulf of Mexico Estuarie
Single copies of the Supplemental Appendices and the additional Supplemental Al
are on file at the Northwest Florida Water Management District Headquarters in
Havana, the Florida State University Marine Laboratory, and the Florida Sea Gri
office at the University of Florida.















3 CONCLUSIONS


Prior to 1975, environmental information concerning Choctawhatchee Bay was

sparce and incomplete. This study documents that information and provides

much of the environmental information required to assess current conditions

in the Bay. Future studies should be undertaken to determine changes in

Choctawhatchee Bay due to either natural or cultural influences.

Choctawhatchee Bay is an estuarine embayment dominated by freshwater

inflow. Salinities in the Bay are controlled by the volume of freshwater

inflow due to topography of the Bay and the proximity and depth of East Pass.

Since East Pass is much shallower than the central Bay the heavier, higher

salinity water from the Gulf of Mexico becomes trapped below the freshwater

from the tributaries. This process causes Choctawhatchee Bay to become highly

stratified except during climatic disturbances such as Hurricane Eloise in

1975. Temperature was found to regulate dissolved oxygen concentrations in

Choctawhatchee Bay with increasing temperatures depleting concentrations of

dissolved oxygen. The mechanism of cause is thought to be both physical gas

laws and biological activity. During summer months, the high temperatures and
ey
stratification cause extremely low dissolved oxygen concentrations in benthic
idix
waters. In bayous around the Bay and near the mouth of Choctawhatchee River

the low freshwater flow in the spring and summer months causes surface waters

to become oxygen depleted.

Productivity in Choctawhatchee Bay is limited by low concentrations of




15










dissolved phosphorus. This is characteristic of other Northwest Florida

Panhandle estuaries. Although tributary input of phosphorous is low it is

relatively constant. Primary producers rapidly deplete dissolved phosphorc

near the mouths of the tributaries to the Bay. These primary producers and

higher levels of the food chain slowly die and settle to the bottom of the

Bay. Here an equilibrium is established at the sediment water interface w

phosphorous dissolved back into the water. The phosphorous recirculates be

into surface waters at the turbidity maximum zone or zone of maximum mixing

surface and bottom waters. The location of this zone is controlled by the

volume of freshwater discharge and in the high flow year of 1975 was found

near stations 17 and 18 in the central Bay. The highest concentrations of

chlorophyll were found at these stations suggesting high productivity and/(

large numbers of senescent phytoplankton.

Nitrate, nitrite, ammonia, and organic nitrogen all enter the Bay throat

fluvial loading. However, the principal nitrogen compound leaving the Bay

East Pass is organic nitrogen. This indicates that nitrate, nitrite and

ammonia are deposited in the sediments of the Bay through physical and

biological processes. These compounds follow a similar trend to phosphorot

where they become remineralized in the sediments and are released back inti

the water column.






Ir -------------


Choctawhatchee Bay


East Pass
C---
organic nitrogen
and phosphorous


Choctawhatchee River


phosphorous compounds


nitrate, nitrite nitrogen compounds
and ammonia


---II---
flocculated and
organic, nitrogen
and phosphorous


Box Model Depicting Nutrient Flux in Choctawhatchee Bay.


productivity






dissolved
phosphorous


Figure 3-1:















4 LITERATURE SYNOPSIS


PHYSICAL CHARACTERISTICS


Climatology


Choctawhatchee Bay, in the Northwest Florida Panhandle, is geographical

located in the semi-tropical region of the northern hemisphere. This region

is characterized by annual temperatures of about 68F and 50 inches average

annual rainfall. Storm fronts for the Florida Panhandle general move in a

southeasterly direction, while winter winds originate predominately from the

north (Taylor Biological Co., 1977). Goldsmith, 1966, reported the prevail

winds to be northerly from September to February and southerly from March tc

August, showing a distinct temporal pattern. The temporal variation of tem-

perature precipitation, wind speed and wind direction play an important role

in the nature of the Bay.

Daily weather conditions were obtained from the Department of the Air

Force at Eglin Air Force Base, Florida, which is located on the northern she

of Choctawhatchee Bay. Air temperature'in 1975, as depicted in Figure 4-1,

exhibits a seasonal pattern, while short term variation is the result of stc

events and local disturbances. Temperature patterns for the five years pre-

vious to and including 1975 are shown in Figure 4-2. The average annual tem-

perature for 1975 was 67.4F, slightly below that of the five previous year!

but very close to the regional long term mean. This slight depression in tf















4 LITERATURE SYNOPSIS


PHYSICAL CHARACTERISTICS


Climatology


Choctawhatchee Bay, in the Northwest Florida Panhandle, is geographical

located in the semi-tropical region of the northern hemisphere. This region

is characterized by annual temperatures of about 68F and 50 inches average

annual rainfall. Storm fronts for the Florida Panhandle general move in a

southeasterly direction, while winter winds originate predominately from the

north (Taylor Biological Co., 1977). Goldsmith, 1966, reported the prevail

winds to be northerly from September to February and southerly from March tc

August, showing a distinct temporal pattern. The temporal variation of tem-

perature precipitation, wind speed and wind direction play an important role

in the nature of the Bay.

Daily weather conditions were obtained from the Department of the Air

Force at Eglin Air Force Base, Florida, which is located on the northern she

of Choctawhatchee Bay. Air temperature'in 1975, as depicted in Figure 4-1,

exhibits a seasonal pattern, while short term variation is the result of stc

events and local disturbances. Temperature patterns for the five years pre-

vious to and including 1975 are shown in Figure 4-2. The average annual tem-

perature for 1975 was 67.4F, slightly below that of the five previous year!

but very close to the regional long term mean. This slight depression in tf


















FIGURE 4-1 r DAILY AIR TEMPERATURE DURING 1975 AT
EGLIN AIR FORCE BASE, FLORIDA.


JAN FEB AR APR HAY JUN JUL AUG SEP OCT NOV DEC

MONTHS


FIGURE 4-2 : AVERAGE MONTHLY AIR TEMPERATURES FROM 1970 TO
1975 AT EGLIN AIR FORCE BASE, FLORIDA.


1970


1971 1972 1973 1974 1975

YEARS


... .... ... .... ... ....' '' '' '' '' '' ~ ~~'''~''~~










annual average temperature appears to be the result of a longer winter seas

than in the previous five years. Figure 4-1 shows temperature fluctuations

1975 to be sporadic in the winter and smoother, steady state in the summer.

sharp decrease in temperature occurred midway through October and below

average temperatures occurred in early March.

The amount of rainfall within a region will control both surfaces and

ground water discharge. This directly affects flow rates in the tributaries

and thus in turn, circulation and salinity within the Bay. Five years of

monthly rainfall data from 1970 to 1975 show a departure in normal rainfall

patterns for the year 1975 (Figure 4-4). The annual total precipitation fo

1975 was 97.27 inches, almost double the mean of the proceeding four years

(Figure 4-5). The regional average annual amount of rainfall is 62.3 inches

year (U.S. Department of Commerce). The departure from the mean may be att

buted to extremely high rainfall in late 3uly, 1975, and Hurricane Eloise i

September, 1975, (Figure 4-3). These high precipitation periods generally

depress salinity and increase suspended sediments in the Bay.

Figure 4-6 depicts cloud cover percentiles for the year 1975. In 1975,

weather data from Eglin Air Force Base, Florida, show clear days to account

for only 28.5 percent of the year.

Wind speed and wind direction aid in mixing of surface and bottom water

Wind mixing facilitates increased gas transport and oxygenation of surface

waters. Wind mixing in shallow depths of the Bay causes resuspension of se,

ments which reintroduces metals and toxics into the water as well as causin

an increase in chemical and biological oxygen demand in the water column.

Strong winds, acting on a large embayment of water such as Choctawhatchee B

can also affect circulation patterns by causing a temporary pile up of water



















FIGURE 4-3 1 DAILY PRECIPITATION DURING 1975 AT
EGLIN AIR FORCE BASE. FLORIDA.


JAN FEB MAR APR MAY JUN


JU AUB SEP OCT NOV


MONTHS


FIGURE 4-4 : AVERAGE MONTHLY PRECIPITATION FROM 1970 TO
1975 AT EGLIN AIR FORCE BASE, FLORIDA.


YEARS


t












FIGURE 4-5 = ANNUAL PRECIPATION FROM 1971
AT EGLIN AIR FORCE BASE, FLORIDA.


Vj~


1971


7i~i




4;ii


1972


Vj~i


1973


1974


TO 1975


1975


YEARS








FIGURE 4-6 : CLOUD COVER PERCENTAGES FOR THE YEAR
1975, AT EGLIN AIR FORCE BASE, FLORIDA.


PiL(Lf _________ __________I Cnia


PARTLY
CLOUDY


CLOUDY


CLEAR


I


I 0l


l









one end of the Bay. Figure 4-7 shows the largest percent of wind to originate

from the north with southerly and southeasterly wind directions accounting for

a combined 24.29 percent of the prevailing winds directions. This is in

agreement with figures from the Escambia Bay Recovery Study (U.S. Environmental

Protection Agency, 1975). EPA, 1975, also shows average wind velocity to be

lower in the summer months than in winter months.



Hydrodynamics


Circulation within Choctawhatchee Bay can be described as two layered flow

with entrainment of the bottom, higher salinity water underneath the

freshwater, surface layers (Dyer, 1973). The two layered flow pattern is

fosthered by the bathymetry of the Bay, and the proximity of both East Pass and

Choctawhatchee River to the Bay. The effect which Santa Rosa Sound exhibits

on the circulation of the Bay is not described and remains unexplained here.

The depth in Choctawhatchee Bay decreases from east to west, with a maxi-

mum depth of 43 feet located about one mile northeast of East Pass (Figure

4-9). This gentle slope allows benthic tidal water to move slowly into the

eastern reaches of the Bay, but generally it does not cause strong mixing by

upward currents of higher salinity tidal water with the overflowing freshwater

from the tributaries. In the Bay west of Niceville, increased mixing of tidal

water and freshwater are probably due to this area's proximity to East Pass,

as well as the greater inclination of the bottom in near shore regions. As

incoming tidal water reaches these steeper inclines, the water is forced

upward mixing it with the overlying freshwater layer. The gradual slope

toward the eastern end of the Bay allows the tidal water to disperse more




23











FIGURE 4-7 1 WIND DIRECTION PERCENTAGES FOR THE YEAR
1975, AT EGLIN AIR FORCE BASE, FLORIDA.


E ENE ESE N NNENNW NW S SE SSE SSW SW
WIND DIRECTION


U WNW WSW


FIGURE 4-8 : ANNUAL AVERAGE AIR TEMPERATURE FOR THE YEAR
1975, AT EGLIN AIR FORCE BASE, FLORIDA.


1971


pl/


1972


1973
YEARS


p


1974


1975


70 8


IIIIIIIIIIII'II ~'I I --r.








r "---I-~- I~- -~


MGORLN POINT

---r- ( -- 1 1 1 1^ ~ ~ ^ ^

H 1 ""Mto s "o


Figure 4-9: Station Depths in Choctawhatchee Bay


I










slowly along the bottom toward the east, creating the two layered flow system

The major cause of bottom water entrainment in Choctawhatchee Bay is th(

shallow depth at East Pass which is maintained at 12 feet by the U.S. Corps

Engineers, 1975. This greatly inhibits tidal flushing of bottom waters as

tidal amplitude ranges greater than one foot outside East Pass, about 0.8 f(

in East Pass and less than 0.5 feet at the State Highway 331 bridge crossing

the eastern end of the Bay. The low tidal ranges are characteristic of the

diurnal tides of the northern Gulf of Mexico, and they are very low energy

tides when compared to most other United States coastlines. As a result,

tides play a much smaller role in the circulation and net flushing of

Choctawhatchee Bay than does freshwater discharge.

Due to the minor role of tides in the Bay, freshwater discharge and run(

usually govern circulation, nutrient loadings, salinity and sedimentation

rates. Discharge from the Choctawhatchee River ranges from 3,400 cubic feel

second/day (cfsd) to a high of 28,000 cfsd. Higher discharge rates normally

occur in mid-summer. Within Choctawhatchee Bay, Goldsmith, 1966, found sur-

face velocity rates at East Pass to be 1.0 knots, while all other flow velo(

ties throughout the Bay were less than 0.5 knots. The U.S. Fish and Wildlii

Service, 1969, found both bottom and surface flow velocities in the Bay to I

about 0.5 knots and East Pass flow velocities to average 1.0 knots. Also st

face waters were found to have a gentle westerly drift and tidal waters on

bottom were found to move at least as far east as the State Highway 331

bridge. Movement of bottom waters in the Bay has been traced through foram.

niferal test deposition in the sediments (Pastula, 1967). Deposits of foral

niferal tests in the sediments indicate historical zones of freshwater and

water interfaces where the calcified tests settle to the bottom in the lowe




-r~



density freshwater (Figure 4-10). The presence of these foraminifern tests

are indicative that the Bay was once a higher salinity Bay with greater

topographical variation causing upwelling of tidal water into overlying fresh-

water and deposition of foraminiferan tests.

Surface water flow in the eastern end of the Bay is depicted in reproduced

NASA photographs of flood water sediments in the Bay (Figure 4-11). This

interpretation of the photograph shows a water mass moving westward with

eddies of the main stream of flow moving into the shallow bayous along with

southern shores of the Bay.

Through the above documentation and suggestions of the frequent presence

of a strong salinity gradient, it may be concluded that little mixing of

salt water and freshwater occurs in Choctawhatchee Bay. As freshwater

flows to East Pass, the underlying bottom waters are slowly removed by

outgoing tides. Ross, Anderson and 3enkins, 1974, suggest that the salt water

exchange rate in Choctawhatchee Bay is only 14% during each tidal cycle. The

major portion, i.e. 86 percent of the incoming tide, is comprised of both

freshwater and tidal water exchanged through previous tidal cycles. For this

reason Ross, Anderson and Jenkins, 1974, predicted the overall flushing rate

of the Bay to exceed one year. As mentioned previously, the reasons for this

are probably the location of East Pass and Choctawhatchee River, as well as

the depth of East Pass. These characteristics foster low tidal amplitude at

1.0 feet compared to 1.5 feet for nearby Pensacola Bay and St. Andrews Bay,

and causes a 2 to 2.5 hour lag in tides from East Pass to the State Highway

331 bridge.

In 1975, freshwater discharge from Choctawhatchee River peaked in April






27









one end of the Bay. Figure 4-7 shows the largest percent of wind to originate

from the north with southerly and southeasterly wind directions accounting for

a combined 24.29 percent of the prevailing winds directions. This is in

agreement with figures from the Escambia Bay Recovery Study (U.S. Environmental

Protection Agency, 1975). EPA, 1975, also shows average wind velocity to be

lower in the summer months than in winter months.



Hydrodynamics


Circulation within Choctawhatchee Bay can be described as two layered flow

with entrainment of the bottom, higher salinity water underneath the

freshwater, surface layers (Dyer, 1973). The two layered flow pattern is

fosthered by the bathymetry of the Bay, and the proximity of both East Pass and

Choctawhatchee River to the Bay. The effect which Santa Rosa Sound exhibits

on the circulation of the Bay is not described and remains unexplained here.

The depth in Choctawhatchee Bay decreases from east to west, with a maxi-

mum depth of 43 feet located about one mile northeast of East Pass (Figure

4-9). This gentle slope allows benthic tidal water to move slowly into the

eastern reaches of the Bay, but generally it does not cause strong mixing by

upward currents of higher salinity tidal water with the overflowing freshwater

from the tributaries. In the Bay west of Niceville, increased mixing of tidal

water and freshwater are probably due to this area's proximity to East Pass,

as well as the greater inclination of the bottom in near shore regions. As

incoming tidal water reaches these steeper inclines, the water is forced

upward mixing it with the overlying freshwater layer. The gradual slope

toward the eastern end of the Bay allows the tidal water to disperse more




23




































































iORE.NO POINT


NAUTICAL MILES

YARDS -
iosnl=Epf i '*'" '' *0 ^ -


Figure 4+|o0: Foraminiferal distribution in Choctawhatchee Bay

sediments (from Pastula, 1967).













































MORENO POINT



YARDS


Figure q-11 : Silt laden freshwater entering Choctawhatchee Bay
during a March, 1975 storm (from NASA ERTS photograph).


r









with minor peaks occurring in August and October (Figure 4-16). The unseaso

high discharge rates in August and October are due to high precipitation in

late 3uly and Hurricane Eloise in late September. These unseasonal events

are represented strongly in several smaller tributaries to the Bay (Figures

4-17, 4-18, 4-19). Figures 4-12, 4-13, 4-14 and 4-15 show annual discharge

trends from 1968 to 1978. All stations, excluding juniper Creek near

Niceville, had the highest discharge occurring in 1975.


Water Temperature


Water temperature exhibits seasonal trends based on air temperature and

solar insolation. Water temperature is also an important limiting factor fo

the biotic communities within an estuary. Alteration of the temperature

regimes in an estuary will often drastically alter productivity and food-web

dynamics (O'Connor and McErlean, 1975). Increasing temperatures, fresh-wate

discharge and increasing nutrient loadings have been suggested to be the

controlling factors in spring blooms in other Northwest Florida estuaries

(Estabroda, 1973; Myers and Iverson, 1977). Increasing summer water tempera

ture is thought to be the cause of increased biological oxygen demand and ch

mical oxygen command (U.S. Environmental Protection Agency, 1975),

particularly in the sediments. As shown by Ferguson and Murdock, 1975, high

temperatures increase the standing crop of heterotrophic microbes which will

deplete both dissolved oxygen and benthic detrital concentrations. Therefore

with the slow tidal exchange in Choctawhatchee Bay, temperatures play an

important role in causing depressed dissolved oxygen levels in bottom waters

Ritchie, 1965, found only slight differences in water temperature in the sur

face and bottom waters. Similar results were found by U.S. Fish and Wildlif















FIGURE LH-11 AVERAGE ANNUAL DISCHARGE FROM JUNIPER CREEK
NEAR STATE ROAD 85. NICEVILLE, FLORIDA FROM 1968 TO 1978.


8L-
1968


1970 1972 1974 1976


1978


YEARS


FIGURE f-13 = AVERAGE ANNUAL DISCHARGE FROM ALAQUA
CREEK NEAR DEFUNIAK SPRINGS, FLORIDA FROM 1988 TO 1978.


1978


C 350
U
B
I 380
C

F 250
E
E
T 280
P
E
R 158

S
E 18800
C
0
N 50
D


80
191



j l


s8 1970 1972 1974 1976
YEARS















FIGURE L.-/l AVERAGE ANNUAL DISCHARGE FROM MAGNOLIA
CREEK NEAR FREEPORT, FLORIDA FROM 1968 TO 1978.


1970 1972 1974 1976

YEARS


1978


FIGURE H4-i5

15000




C12000
U
B
I
C
988000
F
E
E
T
P 6800
E
R
S
E 3000
C
0
N
D


AVERAGE ANNUAL DISCHARGE FROM CHOCTAWHATCHEE RIVER
NEAR BRUCE, FLORIDA FROM 1968 TO 1978.


1968 1970 1972 1974 1976

YEARS


0
1968


1978
















FIGURE H-lb6: MEAN MONTHLY DISCHARGE FROM CHOCTAWHATCHEE
RIVER NEAR BRUCE, FLORIDA IN THE YEAR 1975.


30000



25800



20000



15888



18888



sese
1000























125




10e




75




59


JAN FEB MAL APR MAY JUN JUL AU SEP OCT NOV DEC

MONTHS


JAN FEB MAR APR HAY JUN JUL AUG SEP OCT NOV DEC

MONTHS












FIGURE L-)71 MEAN MONTHLY DISCHARGE FROM MAGNOLIA
CREEK NEAR FREEPORT, FLORIDA FOR THE YEAR 1975.


















FIGURE l-/18 MEAN MONTHLY DISCHARGE FROM ALAQUA CREEK
NEAR DEFUNIAK SPRINGS. FLORIDA IN THE YEAR 1975.


JAN FEB NAR APR MAY


UN UL AUG SEP OCT NOV DEC


MONTHS


FIGURE 4q-q: MEAN MONTHLY DISCHARGE FROM JUNIPER CREEK
NEAR STATE HIGHWAY 85, NICEVILLE, FLORIDA IN THE YEAR 1975.


388


259


se -


MONTHS


1000




800




600


J I I IA I IA IY I I I ID
JAN FEB lAR APR MAY JUN JUL AU OEP OCT NDV DEC









with minor peaks occurring in August and October (Figure 4-16). The unseaso

high discharge rates in August and October are due to high precipitation in

late 3uly and Hurricane Eloise in late September. These unseasonal events

are represented strongly in several smaller tributaries to the Bay (Figures

4-17, 4-18, 4-19). Figures 4-12, 4-13, 4-14 and 4-15 show annual discharge

trends from 1968 to 1978. All stations, excluding juniper Creek near

Niceville, had the highest discharge occurring in 1975.


Water Temperature


Water temperature exhibits seasonal trends based on air temperature and

solar insolation. Water temperature is also an important limiting factor fo

the biotic communities within an estuary. Alteration of the temperature

regimes in an estuary will often drastically alter productivity and food-web

dynamics (O'Connor and McErlean, 1975). Increasing temperatures, fresh-wate

discharge and increasing nutrient loadings have been suggested to be the

controlling factors in spring blooms in other Northwest Florida estuaries

(Estabroda, 1973; Myers and Iverson, 1977). Increasing summer water tempera

ture is thought to be the cause of increased biological oxygen demand and ch

mical oxygen command (U.S. Environmental Protection Agency, 1975),

particularly in the sediments. As shown by Ferguson and Murdock, 1975, high

temperatures increase the standing crop of heterotrophic microbes which will

deplete both dissolved oxygen and benthic detrital concentrations. Therefore

with the slow tidal exchange in Choctawhatchee Bay, temperatures play an

important role in causing depressed dissolved oxygen levels in bottom waters

Ritchie, 1965, found only slight differences in water temperature in the sur

face and bottom waters. Similar results were found by U.S. Fish and Wildlif







Service, 1968, while spatially, temperatures in the Bay ranged from 19.8

degrees centrigrade to a low of 13.7 degrees centigrade in the middle of March.


pH


Tributaries to Choctawhatchee Bay, excluding Choctawhatchee River, are

slightly acidic with a pH as low as about 5.0 to 6.50 (U.S. Geological

Society, 1980). The source waters of Choctawhatchee River arise in regions

which are characterized by the Northwest Florida Water Management District as

having a chemical type consisting of calcium and magnesium bicarbonates

(Northwest Florida Water Management District, 1978). This could lead to a

fluvial input of slightly alkaline pH waters in the eastern end of the Bay.

This hypothesis is supported by Battelle Columbus Lab, 1977, in a baywide sur-

vey of pH. Battelle-Columbus Lab., 1977, found pH to be higher in surface

fresh waters and decreasing slightly with increasing depth. The ranges in

the main Bay were from 7.0 to 8.1 while in the more freshwater dominated

intercoastal canal the pH ranged from 7.4 to 8.0.


Salinity


The characteristic feature of an estuarine habitat is the brackish water,

or water of a reduced salinity when compared to oceanic realms. The actual

measured salinity depends on the degree of mixing between inflowing fresh

water with resident tidal salt water. Some forces in control of the mixing of

fresh and salt water include the water density of both sources, volume of

river inflow and tidal transport, tidal resurgency, meteorological conditions

and the bathymetry of the estuarine system. Since chlorides in sea water are

conservative elements, they may be used as tracers of the aforementioned







Service, 1968, while spatially, temperatures in the Bay ranged from 19.8

degrees centrigrade to a low of 13.7 degrees centigrade in the middle of March.


pH


Tributaries to Choctawhatchee Bay, excluding Choctawhatchee River, are

slightly acidic with a pH as low as about 5.0 to 6.50 (U.S. Geological

Society, 1980). The source waters of Choctawhatchee River arise in regions

which are characterized by the Northwest Florida Water Management District as

having a chemical type consisting of calcium and magnesium bicarbonates

(Northwest Florida Water Management District, 1978). This could lead to a

fluvial input of slightly alkaline pH waters in the eastern end of the Bay.

This hypothesis is supported by Battelle Columbus Lab, 1977, in a baywide sur-

vey of pH. Battelle-Columbus Lab., 1977, found pH to be higher in surface

fresh waters and decreasing slightly with increasing depth. The ranges in

the main Bay were from 7.0 to 8.1 while in the more freshwater dominated

intercoastal canal the pH ranged from 7.4 to 8.0.


Salinity


The characteristic feature of an estuarine habitat is the brackish water,

or water of a reduced salinity when compared to oceanic realms. The actual

measured salinity depends on the degree of mixing between inflowing fresh

water with resident tidal salt water. Some forces in control of the mixing of

fresh and salt water include the water density of both sources, volume of

river inflow and tidal transport, tidal resurgency, meteorological conditions

and the bathymetry of the estuarine system. Since chlorides in sea water are

conservative elements, they may be used as tracers of the aforementioned









characteristics depicting the circulation of an estuary. Secondly, the sa.

nity is often the item of primary importance in determining the distribution

of marine organisms in a tidal estuary. Estuarine organisms, for the most

part, have wide salinity ranges, but are limited as salinities approach thi

of either freshwater or oceanic waters.

Choctawhatchee Bay has been characterized as having two layer flow witl

vertical mixing in the east and two layer flow with entrainment of the bott

water in the middle and western regions (U.S. Environmental Protection Ager

1975). The freshwater flow moves from Choctawhatchee River to East Pass as

surface flow while the denser high salinity bottom waters move slowly with

tides. The deep, gentle sloping bottom and shallow outlet to the Gulf of

Mexico helps entrain the bottom waters except in the eastern reaches where

Bay is shallow. Bowden, 1967, shows a positive relationship between slope

the bottom and increased tidal mixing rates which would indicate strong mix

in western bayous and moderate mixing throughout the central and eastern Ba

The U.S. Army Corps of Engineers report increased tidal exchange through th

mouth of East Pass with every periodic dredging, but no harm occurs to the

ecosystem (U.S. Army Corps of Engineers, 1975). The U.S. Environmental

Protection Agency, 1975, reports constant surface salinities and bottom

salinities which decrease slightly with decreasing bottom depth toward the

east. During periods of low freshwater inflow from Choctawhatchee River,

greater tidal salt water exchange results forcing the movement of the dense.

higher salinity bottom water in the Bay toward the mouth of the River. Thi!

bottom water moves along both natural and maintained channels from which th(

higher salinity bottom water overflows and mixes with overlying freshwater

(U.S. Army Corps of Engineers, 1973). Sea water and freshwater mixing is a]








reported to occur in the western bayous and around the shallow perimeter of

the Bay, though it is not as important as toward the center of the middle and

eastern end of the Bay (U.S. Fish and Wildlife Service, 1975).

The strong halocline commonly found in Choctawhatchee Bay (Ritchie, 1961;

U.S. Department of the Interior, 1968; Collard, 1976) is the result of reduced

tidal mixing, not an arrested salt wedge. The degree of mixing increases with

increasing tidal energy and is reduced in a low tidal energy system such as

Choctawhatchee Bay. In Choctawhatchee Bay the salt wedge penetrates at times

well into the eastern end of the Bay and also up the deep water bayous in the

western end of the Bay. For this reason, the western bayous have greater

flushing rates than those in the eastern Bay, and can handle higher loading

rates of nutrients and organic (Ross, Anderson and Jenkins, 1974). Ross,

Anderson and Jenkins, 1974, also contend that the flushing rate for

Choctawhatchee Bay is less than 14 percent of new Gulf of Mexico oceanic water

for each tidal cycle. At this rate, the estimated transport rate of nutrients

entering the Bay from Choctawhatchee River and leaving via East Pass will

slightly exceed one year. Attributing to the long residence of nutrients in

Choctawhatchee Bay is the reduced tidal exchange and velocity within the Bay.

In Choctawhatchee Bay, a strong halocline exists between the lighter sur-

face fresh waters and the denser bottom waters with as much as a 14 ppt dif-

ference within two feet of water (Collard, 1976). The strong demarkation of

salinity probably results from the velocity of the surface waters and the

bathymetry of the Bay. The submarine topography in the Bay support three

pockets where high salinity water is concentrated (Goldsmith, 1967). These

salt water sinks are not strongly demarked and they remain well connected by

central channels in the Bay through tidal movement. Tidal movement is slight









and the resulting sluggish flow rates and the strong halocline lead to oth

problems which have been documented for the main Bay. Bottom waters in

Choctawhatchee Bay are often depleted of dissolved oxygen. This, along wi

sedimentation in the central and eastern Bay, often lead to anaerobic con-

ditions resulting in a biologically barren deep water region (Taylor

Biological Co., 1978).


Dissolved Oxygen


Dissolved oxygen content is a strong indicator of current environmental

conditions within an estuary. When dissolved oxygen is low, metabolic pro

cesses will be reduced accordingly in the estuarine community. Many facto

regulate the dissolved oxygen content in an estuary. In an estuary such a

Choctawhatchee Bay where tributary inflow dominates circulation, the disso

oxygen content from the river will be the major factor in determining

dissolved oxygen in the Bay. During normal and above average discharge co

editions from Choctawhatchee River, the incoming freshwater will increase

dissolved oxygen content in the Bay. However, during low river discharge

periods the river water will consist of drainage from low marshy regions a

underground seepage, both of which are generally oxygen depleted. The bio

mical oxygen demand (BOD), during certain conditions, can also severely de

dissolved oxygen levels. When dissolved and sestonic organic carbon and t

peratures are high, as in the summer, the BOD will increase, thus reducing

dissolved oxygen in the Bay. The greatest BOD in the water column will be

the halocline, which in Choctawhatchee Bay also seems to be the same region

the turbidity maxima. Here sediments and clays tend to flocculate (Postma

1967) and negatively charged dissolved organic precipitate and are adsorb







onto flocculated sediments (Darnell, 1967). These processes are initiated

upon contact with magnesium and calcium ions found in seawater (Postma, 1967).

This region of the turbidity maxima is also where heterotrophic microbes

concentrate, particularly in warmer months when favorable growing conditions

for the microbes exist.

Dissolved oxygen fluctuates largely over a diurnal cycle. This fluc-

tuation increases in regions which are nutrient enriched. The nutrient

enrichment precludes high photosynthetic rates increasing dissolved oxygen

during the day and high respiration rates at night depleting the oxygen

supplies. Temperature affects dissolved oxygen, not only through regulation

of metabolic processes, but also physically through gas constants. As tem-

perature increases, gas solubility decreases and diffusion rates increase.

Thus, during the warmer summer months, the dissolved oxygen content saturation

is lower and dissolved oxygen input from the tributaries is reduced. Also

affecting dissolved oxygen concentrations in the Bay are gas transport rates.

Theoretically, oxygen should be distributed evenly throughout the water

column; however, dissolved gases, including oxygen, are inversely proportional

to salinity. In Choctawhatchee Bay diffusion rates of oxygen to bottom waters

would be disrupted at the halocline causing a reduction in dissolved oxygen

transport to the tidal waters on the bottom. The above conditions create a

zone in Choctawhatchee Bay known as the compensation level, defined as the

level where respiration and decomposition consume oxygen in equal amounts to

that produced or input in a twenty-four hour period (Reid and Wood, 1976).

Contributing to the location of the compensation level is the turbidity of

the water. Increasing turbidity will reduce light penetration of the water








column thereby limiting primary productivity and oxygen production to surfat

waters.

Many studies have found depleted oxygen levels in Choctawhatchee Bay

(Battelle-Columbus Laboratories, 1973; U.S. Environmental Protection Agency,

1975; Ross, Anderson and 3enkins, 1974). In particular, the benthic dissol\

oxygen levels have been cited as problematic (U.S. Environmental Protection

Agency (EPA), 1975). EPA, 1975, found in comparative samples during the

summer of 1974, that nine of twenty-one bottom stations do not meet the

Florida standard (Florida Administrative Code, 1973), for Class II and Clas

III waters. The minimum levels are 4.0 mg/1, except in natural dystrophic

estuaries. Lowest dissolved oxygen levels occurred in deeper waters of the

Bay. In surface waters EPA, 1975, found dissolved oxygen concentrations to

at 70 percent of the saturation concentration at the mouth of Choctawhatchee

River, increasing to 100 percent saturation in the middle of the Bay. This

indicative of acceptable environmental conditions in surface waters of the

Bay. Ross, Anderson and Jenkins, 1974, and the U.S. Fish and Wildlife

Service, 1968, both suggest that lowest dissolved oxygen levels occur in bot

tom waters during periods of high inflow during the late spring and summer,

since benthic dissolved oxygen remains unreplenished due to the strong

halocline.

While analyzing Florida Department of Pollution Control data, Ross,

Anderson and Jenkins, 1974, found BOD rates to range up to 5.4 mg/1 in the

mouth of several minor tributaries. The U.S. Environmental Protection Agenc

1975, found surface BOD ranging from 5.2 mg/1 to 6.2 mg/1 and bottom water E

ranging from 1.8 mg/1 at East Pass to 13.6 mg/1 in the central Bay above

Hogtown Bayou. These data show a potential problem in the deeper waters of









and the resulting sluggish flow rates and the strong halocline lead to oth

problems which have been documented for the main Bay. Bottom waters in

Choctawhatchee Bay are often depleted of dissolved oxygen. This, along wi

sedimentation in the central and eastern Bay, often lead to anaerobic con-

ditions resulting in a biologically barren deep water region (Taylor

Biological Co., 1978).


Dissolved Oxygen


Dissolved oxygen content is a strong indicator of current environmental

conditions within an estuary. When dissolved oxygen is low, metabolic pro

cesses will be reduced accordingly in the estuarine community. Many facto

regulate the dissolved oxygen content in an estuary. In an estuary such a

Choctawhatchee Bay where tributary inflow dominates circulation, the disso

oxygen content from the river will be the major factor in determining

dissolved oxygen in the Bay. During normal and above average discharge co

editions from Choctawhatchee River, the incoming freshwater will increase

dissolved oxygen content in the Bay. However, during low river discharge

periods the river water will consist of drainage from low marshy regions a

underground seepage, both of which are generally oxygen depleted. The bio

mical oxygen demand (BOD), during certain conditions, can also severely de

dissolved oxygen levels. When dissolved and sestonic organic carbon and t

peratures are high, as in the summer, the BOD will increase, thus reducing

dissolved oxygen in the Bay. The greatest BOD in the water column will be

the halocline, which in Choctawhatchee Bay also seems to be the same region

the turbidity maxima. Here sediments and clays tend to flocculate (Postma

1967) and negatively charged dissolved organic precipitate and are adsorb







central Choctawhatchee Bay during September, 1975. Aside from being a natural

occurrence in Choctawhatchee Bay, one possible cause of the high BOD rate

could be increased organic from seasonal demise of phytoplankton populations.

Florida Department of Environmental Regulation, 1979, suggests potential

degradation problems in the western Bay resulting from increased urbanization.

Santa Rosa Sound was found to be relatively healthy in terms of BOD and

benthic diversity.














WATER QUALITY


Phosphorous



In estuarine environments, most phosphorous exists primarily in an inso-

luble form; however, primary producers require it in a soluble form. The

soluble form commonly found in estuaries is composed of orthophosphate,

polyphosphate and organic phosphate. The insoluble forms predominate in the

estuary because of high bacterial utilization, primary productivity, adsorp-

tion onto insoluble residues and formation of insoluble precipitates. The

basic pH conditions of estuaries enhance these processes. Principal alloch-

thonous sources of phosphorous are precipitation and gas transport from the

air, and in some estuaries, from human derived sources. Phosphorous is a co

servative nutrient in estuaries. The precipitated insoluble phosphorous

remains in equilibrium with soluble phosphorous in the water and the ratio o

the two is indirectly mediated by dissolved oxygen concentrations (Webb, 198

Northwestern Gulf of Mexico estuaries are characteristically limited in

terms of productivity by phosphorous. Any major input of phosphorous to the

estuaries could lend to excessive phytoplankton blooms and eutrophication

(Meyers and Iverson, 1981). Choctawhatchee Bay is similar in respect to

phosphorous to many other Northeastern Gulf of Mexico estuaries

(U.S. Environmental Protection Agency, 1975). EPA, 1975, found mean total














WATER QUALITY


Phosphorous



In estuarine environments, most phosphorous exists primarily in an inso-

luble form; however, primary producers require it in a soluble form. The

soluble form commonly found in estuaries is composed of orthophosphate,

polyphosphate and organic phosphate. The insoluble forms predominate in the

estuary because of high bacterial utilization, primary productivity, adsorp-

tion onto insoluble residues and formation of insoluble precipitates. The

basic pH conditions of estuaries enhance these processes. Principal alloch-

thonous sources of phosphorous are precipitation and gas transport from the

air, and in some estuaries, from human derived sources. Phosphorous is a co

servative nutrient in estuaries. The precipitated insoluble phosphorous

remains in equilibrium with soluble phosphorous in the water and the ratio o

the two is indirectly mediated by dissolved oxygen concentrations (Webb, 198

Northwestern Gulf of Mexico estuaries are characteristically limited in

terms of productivity by phosphorous. Any major input of phosphorous to the

estuaries could lend to excessive phytoplankton blooms and eutrophication

(Meyers and Iverson, 1981). Choctawhatchee Bay is similar in respect to

phosphorous to many other Northeastern Gulf of Mexico estuaries

(U.S. Environmental Protection Agency, 1975). EPA, 1975, found mean total







phosphorous to be 0.03 mg/1 and the mean dissolved phosphorous to be

0.013 mg/1 in Choctawhatchee Bay. The eastern region and tributaries seemed

to have higher phosphorous values than the central Bay. The phosphorous

levels found during the Escambia Bay Recovery Study, (EPA, 1975), never

exceeded criteria for total phosphorous of .05 mg/1 established in 1972 (Water

Quality Criteria, 1972). Ross, Anderson and 3enkins, 1974, studied phosphorous

input to Choctawhatchee Bay from fluvial sources, point sources and non-point

sources. These studies indicated that the major source of phosphorous to

Choctawhatchee Bay was from Choctawhatchee River. Toms Bayou and other

bayous in the western Bay and Santa Rosa Sound were also found to have signi-

ficantly higher concentrations of phosphorous than found in the main Bay.

This was thought to be the result of urbanization around the western end of

the Bay.

The principal nutrient index used to characterize phytoplankton blooms is

the phosphorous-nitrogen ratio (P:N ratio). Optimal conditions are suggested

to be as high as 1:20 (Ross, Anderson and 3enkins, 1974), with lower ranges of

1:5 and 1:10 (Webb, 1981). Preliminary observations of data from

Choctawhatchee Bay found P:N ratios as high as 1:50 (Ross, Anderson and

3enkins, 1974), thereby suggesting a high degree of phosphorous limitation in

terms of productivity.


Nitrogen


In estuaries nitrogen is essential to primary productivity; however,

excessive nitrogen, under certain conditions, can contribute to eutrophication.

Nitrogen compounds in an estuary can come from many allochthonous sources.







phosphorous to be 0.03 mg/1 and the mean dissolved phosphorous to be

0.013 mg/1 in Choctawhatchee Bay. The eastern region and tributaries seemed

to have higher phosphorous values than the central Bay. The phosphorous

levels found during the Escambia Bay Recovery Study, (EPA, 1975), never

exceeded criteria for total phosphorous of .05 mg/1 established in 1972 (Water

Quality Criteria, 1972). Ross, Anderson and 3enkins, 1974, studied phosphorous

input to Choctawhatchee Bay from fluvial sources, point sources and non-point

sources. These studies indicated that the major source of phosphorous to

Choctawhatchee Bay was from Choctawhatchee River. Toms Bayou and other

bayous in the western Bay and Santa Rosa Sound were also found to have signi-

ficantly higher concentrations of phosphorous than found in the main Bay.

This was thought to be the result of urbanization around the western end of

the Bay.

The principal nutrient index used to characterize phytoplankton blooms is

the phosphorous-nitrogen ratio (P:N ratio). Optimal conditions are suggested

to be as high as 1:20 (Ross, Anderson and 3enkins, 1974), with lower ranges of

1:5 and 1:10 (Webb, 1981). Preliminary observations of data from

Choctawhatchee Bay found P:N ratios as high as 1:50 (Ross, Anderson and

3enkins, 1974), thereby suggesting a high degree of phosphorous limitation in

terms of productivity.


Nitrogen


In estuaries nitrogen is essential to primary productivity; however,

excessive nitrogen, under certain conditions, can contribute to eutrophication.

Nitrogen compounds in an estuary can come from many allochthonous sources.








Seemingly insignificant sources in Choctawhatchee Bay are precipitation and

surface nitrogen fixation by certain algal groups. Gaseous nitrogen stays

equilibrium at the surface air water interface; however, this elemental forr

of nitrogen is relatively unimportant to nitrogen cycling within the estuar'

(Webb, 1981). Fluvial loading of nitrogen from tributaries includes input 1

both natural and human sources. Theses sources include surface land runoff,

groundwater seepage and discharge of municipal and industrial waste product!

into waters above the falline or the head of tide. Increased culturally

derived nitrogen input into an estuary through fluvial loading, runoff and

point source discharge often causes eutrophication problems within an estuar

(3aworski, 1981).

Autochthounous nitrogen sources in the estuary are from the death and

decomposition of biotic components of the Bay and from sediment nitrogen

release. These nitrogen cycles within the estuary are well documented (Webb

1981). Nitrogen compounds in an estuary occur in inorganic and organic

fractions. Nitrogen compounds or species most readily used by primary produ

cers include nitrate, nitrite and ammonia. Total nitrogen is computed as th

sum of nitrate, nitrite and total kjeldahls nitrogen (TKN). TKN is computed

as the sum of ammonia nitrogen and organic nitrogen. Water Quality Criteria

1972, suggests a maximum concentration of 0.36 mg/1 of total nitrogen for

coastal oceanic water, however, this value may not be appropriate for

estuaries which may be dominated by high natural sources of nitrogen

compounds. There are no Florida State criteria for nitrogen levels in

estuarine waters.

The U.S. Environmental Protection Agency, 1975, found mean levels of toti




T


nitrogen to average 0.25 mg/1 in Choctawhatchee Bay, well below levels in

Escamia Bay to the west and suggested U.S. Environmental Protection Agency

levels (Water Quality Criteria, 1972). In the same study organic nitrogen was

found to compose an average 74.2 percent of the total nitrogen levels. Ross,

Anderson and 3enkins, 1974, found the range of total nitrogen to be from 0.3

to 0.4 mg/1, with concentration increasing toward the eastern end of the Bay.

This suggests high fluvial loading rates of total nitrogen from Choctawhatchee

River. High total nitrogen levels were found in LaGrange Bayou, Lafayette

Creek, Santa Rosa Sound, Cinco Bayou, Garnier Bayou and Boggy Bayou (Ross,

Anderson and 3enkins, 1974). These high levels were probably the result of

municipal input.


Carbon


Organic carbon represent the concentration of both living and non-living

carbon compounds available to heterotrophic activity and contributing to

microbial biomass. Biggs and Flemer, 1972, suggest in upper estuaries the

concentration of organic carbon to be dominated by fluvial discharge of

allochthonous organic while in lower estuaries the primary organic carbon

sources are through primary productivity. Most of the particulate organic

carbon and flocculated dissolved organic carbons from the river end up in the

sediment where they either become buried or used in heterotrophic activity.

Organic carbon is lost in significant amounts from the estuary through

respiration and tidal circulation in nearly equivalent amounts (Biggs and

Flemer, 1972).

In 1975, the U.S. Environmental Protection Agency found the mean total








organic carbon (TOC) concentration in Choctawhatchee Bay to be 3.4 mg/1.

Generally, the TOC was higher toward Choctawhatchee River and decreasing

toward East Pass. Ross, Anderson and Jenkins, 1974, found many tributaries 1

have a high influx of carbon and suggested that this would increase the biol<

gical oxygen demand in the bayous and eastern Bay. Water Quality Criteria,

1972, suggests a water column concentration of total organic carbon in coast

waters exceeding 2.0 mg/1 to be sufficient to depress dissolved oxygen

concentrations. The U.S. Environmental Protection Agency, 1975, found

Choctawhatchee Bay to have the highest average total carbon content in the

sediments of five Northwest Florida bays. EPA, 1975, also found a general

trend in Northwest Florida estuaries for increasing depths to have increased

volatile organic in the sediments.


Total and Fecal Coliform Bacteria


Coliform bacteria are used as indicators of water quality in terms of

health hazards in the State of Florida. The numbers of coliform bacteria

indicate the degree of fecal pollution in a body of water. The fecal colifor

bacteria represent the percent of the total coliform bacteria which are truly

from fecal origin. In the State of Florida, the median coliform number or

Most Probable Number (MPN) of Class II shellfish harvesting waters, cannot

exceed seventy per one hundred milliliters of water in natural conditions and

no more than two hundred thirty per one hundred milliliters of water in ten

percent of the samples during extreme hydrological conditions. For Class III

waters, which are for recreation, propagation and management of fish and

wildlife, the fecal coliforms should not exceed a monthly average of 200/100




T


nitrogen to average 0.25 mg/1 in Choctawhatchee Bay, well below levels in

Escamia Bay to the west and suggested U.S. Environmental Protection Agency

levels (Water Quality Criteria, 1972). In the same study organic nitrogen was

found to compose an average 74.2 percent of the total nitrogen levels. Ross,

Anderson and 3enkins, 1974, found the range of total nitrogen to be from 0.3

to 0.4 mg/1, with concentration increasing toward the eastern end of the Bay.

This suggests high fluvial loading rates of total nitrogen from Choctawhatchee

River. High total nitrogen levels were found in LaGrange Bayou, Lafayette

Creek, Santa Rosa Sound, Cinco Bayou, Garnier Bayou and Boggy Bayou (Ross,

Anderson and 3enkins, 1974). These high levels were probably the result of

municipal input.


Carbon


Organic carbon represent the concentration of both living and non-living

carbon compounds available to heterotrophic activity and contributing to

microbial biomass. Biggs and Flemer, 1972, suggest in upper estuaries the

concentration of organic carbon to be dominated by fluvial discharge of

allochthonous organic while in lower estuaries the primary organic carbon

sources are through primary productivity. Most of the particulate organic

carbon and flocculated dissolved organic carbons from the river end up in the

sediment where they either become buried or used in heterotrophic activity.

Organic carbon is lost in significant amounts from the estuary through

respiration and tidal circulation in nearly equivalent amounts (Biggs and

Flemer, 1972).

In 1975, the U.S. Environmental Protection Agency found the mean total








organic carbon (TOC) concentration in Choctawhatchee Bay to be 3.4 mg/1.

Generally, the TOC was higher toward Choctawhatchee River and decreasing

toward East Pass. Ross, Anderson and Jenkins, 1974, found many tributaries 1

have a high influx of carbon and suggested that this would increase the biol<

gical oxygen demand in the bayous and eastern Bay. Water Quality Criteria,

1972, suggests a water column concentration of total organic carbon in coast

waters exceeding 2.0 mg/1 to be sufficient to depress dissolved oxygen

concentrations. The U.S. Environmental Protection Agency, 1975, found

Choctawhatchee Bay to have the highest average total carbon content in the

sediments of five Northwest Florida bays. EPA, 1975, also found a general

trend in Northwest Florida estuaries for increasing depths to have increased

volatile organic in the sediments.


Total and Fecal Coliform Bacteria


Coliform bacteria are used as indicators of water quality in terms of

health hazards in the State of Florida. The numbers of coliform bacteria

indicate the degree of fecal pollution in a body of water. The fecal colifor

bacteria represent the percent of the total coliform bacteria which are truly

from fecal origin. In the State of Florida, the median coliform number or

Most Probable Number (MPN) of Class II shellfish harvesting waters, cannot

exceed seventy per one hundred milliliters of water in natural conditions and

no more than two hundred thirty per one hundred milliliters of water in ten

percent of the samples during extreme hydrological conditions. For Class III

waters, which are for recreation, propagation and management of fish and

wildlife, the fecal coliforms should not exceed a monthly average of 200/100








milliliters, and no more than 400 total coliforms per 100 milliliters of water

in ten percent of the samples. Also, the fecal coliforms should not exceed

800/100 milliliters of water on any given day, nor 2,400 total coliforms per

100 milliliters of water on a given day. For total coliforms, the monthly

average should be less than 1000/100 milliliters in 20 percent of the samples

within a month. Monthly averages for the above are expresses as a geometric

mean based on a minimum of 100 samples taken over a 30 day period.

Significant coliform bacteria numbers in the water column are usually

indicative of untreated sewage input into an estuary through both point source

and non-point source discharge. In Choctawhatchee Bay most of the waste load

in 1975 was due to stream discharge while the lowest loading was from urban

runoff (Ross, Anderson and Jenkins, 1974). Ross, Anderson and 3enkins, 1975,

found high coliform levels in Santa Rosa Sound. The high number of municipa-

lity point source dischargers in the urbanized western end of the Bay may have

contributed to declining water quality (Figure 4-20). Another problem asso-

ciated with urbanization which possibly could contribute to declining water

quality in the western Bay, is the drainage of private septic tanks for which

loadings are not estimable (Ross, Anderson and 3enkins, 1974).



























minor point sources


Figure 4-20: Point Source Inputs, Submerged Grass Beds, and Major
Fishing Grounds in Choctawhatchee Bay. (in part from McNulty)















BIOTIC COMMUNITIES AND NATURAL RESOURCES


Plankton



Studies of planktonic communities in Choctawhatchee Bay are scarce.

Battelle-Columbus Lab., 1973, assessed plankton numbers at several stations

in the eastern end of the Bay in a single sampling period. The principal cc

ponent of the zooplankton proved to be copepod nauplil, probably the species

Acartia tonsa, the dominant zooplankter in Northwest Florida estuaries (U.S.

Environmental Protection Agency, 1975). Battelle-Columbus Lab., 1973,

concludes there is a functional relationship between temperature and

zooplankton. However, this hypothesis would be difficult to explain based o

one day of sampling at only a few stations. Studies in Santa Rosa Sound nea

Pensacola Bay (Moshiri, et al., 1978) and in the St. Andrews Bay system

(Hopkins, 1966), both found large numbers of rotiferans near freshwater trib

taries and cirripedia nauplii, polychaete larvae and ctenophores occurring

seasonally. The dominant species in both studies throughout the year was th

calanoid copepod Acartia tonsa.

Battelle-Columbua Lab., 1973, found the dominant phytoplankton phyla to

the Chrysphyta, more specifically, the Bacillariophyceae or diatoms. Number

of phytoplankton from stations nearer the tributaries are distinctly greater

than those from the more centrally located stations in eastern Choctawhatche.















BIOTIC COMMUNITIES AND NATURAL RESOURCES


Plankton



Studies of planktonic communities in Choctawhatchee Bay are scarce.

Battelle-Columbus Lab., 1973, assessed plankton numbers at several stations

in the eastern end of the Bay in a single sampling period. The principal cc

ponent of the zooplankton proved to be copepod nauplil, probably the species

Acartia tonsa, the dominant zooplankter in Northwest Florida estuaries (U.S.

Environmental Protection Agency, 1975). Battelle-Columbus Lab., 1973,

concludes there is a functional relationship between temperature and

zooplankton. However, this hypothesis would be difficult to explain based o

one day of sampling at only a few stations. Studies in Santa Rosa Sound nea

Pensacola Bay (Moshiri, et al., 1978) and in the St. Andrews Bay system

(Hopkins, 1966), both found large numbers of rotiferans near freshwater trib

taries and cirripedia nauplii, polychaete larvae and ctenophores occurring

seasonally. The dominant species in both studies throughout the year was th

calanoid copepod Acartia tonsa.

Battelle-Columbua Lab., 1973, found the dominant phytoplankton phyla to

the Chrysphyta, more specifically, the Bacillariophyceae or diatoms. Number

of phytoplankton from stations nearer the tributaries are distinctly greater

than those from the more centrally located stations in eastern Choctawhatche.









Bay (Battelle-Columbus Lab, 1973). This possibly is the result of high

nutrient input from the tributaries which are immediately utilized by the

phytoplankton. General phytoplankton trends in Santa Rosa Sound near

Pensacola Bay are for large numbers of dinoflagellates to occur in late winter

and early spring (Moshiri, et al., 1980; Moshiri, et al., 1978). These give

way to large numbers of single celled algae of many classes in the late spring

followed by high numbers of Bacillariophycae in the late summer, remaining pre-

valent until midwinter. Cell counts in the Choctawhatchee Bay have been

recorded as high as 230,000 cells/milliliters (U.S. Environmental Protection

Agency, 1975). Ross, Anderson and Jenkins, 1975, speculated that the phy-

toplankton growth in the eastern end of Choctawhatchee Bay would be greater

than in the western and central bay based on nutrient input from

Choctawhatchee River.

A better estimate of productivity than phytoplankton numbers is the volume

of chlorophyll pigment retained in the water column. Active growing phy-

toplankton populations will have a greater chlorophyll content than phy-

toplankton populations on the demise. Chlorophyll content represents the

physiological state of phytoplankton cells and thus, in turn, the productivity

potential. The U.S. Environmental Protection Agency, 1975, made a comparative

study of uncorrected chlorophyll in Choctawhatchee Bay. Chlorophyll in the

water column showed a decrease from Choctawhatchee River to the mouth of the

Bay at East Pass with a range from 8.0 mg/1 to 0.0 mg/l. The study also found

chlorophyll to decrease from the central Bay to the peripheral Bayous and

Santa Rosa Sound. The average for the entire Bay for 20 stations was 4.2 mg/l.









This supports the hypothesis of high utilization of nutrients near inflow

points and potential nutrient limitations in the central region of the Bay.


Benthos


Choctawhatchee Bay has several distinct types of benthic habitats which

support varied communities of macroinvertebrates. Benthic faunal surveys in

Escambia Bay to the west of Choctawhatchee Bay (U.S. Environmental Protectior

Agency, 1975) revealed three major benthic habitat descriptions which would

apply to habitats in Choctawhatchee Bay. Marginally, Choctawhatchee Bay is

fringed with a shallow sand shelf. This blends into deeper regions with

varying mixtures of sand and mud comprising the transitional zone. Lastly,

there is a broad central deepwater mud plain. Other smaller habitats,

possibly of more importance, are the grass beds and oyster beds. The grass

beds and oyster beds provide substrate for attachment, shelter, feeding and

reproduction of macroinvertebrates. Also, these areas should have a greater

species diversity than found in the three major habitats of the Bay.

Studies of the benthic macroinvertebrate communities in Choctawhatchee Ba

have been made by the Corps of Engineers in 1974 and 1976, Taylor Biological

Co., 1978*, Battelle-Columbus Lab., 1973, and Ross and Jones, 1979. Ross and

Jones, 1979, found sixty four species at eighteen stations in six primary





*Radcliff Company, Mobile, Alabama, removed eight million cubic yards of

oyster shell from the sediments of Choctawhatchee Bay from 1946 to 1970. In

an effort to extend this dredging activity, Taylor Biological Company, 1978,

performed a study to assess dredging activities in the Bay.































































Figure 4-22: Map Depicting Oyster Beds and Areas Closed to Shellfishing in 1970.


___~li~









This supports the hypothesis of high utilization of nutrients near inflow

points and potential nutrient limitations in the central region of the Bay.


Benthos


Choctawhatchee Bay has several distinct types of benthic habitats which

support varied communities of macroinvertebrates. Benthic faunal surveys in

Escambia Bay to the west of Choctawhatchee Bay (U.S. Environmental Protectior

Agency, 1975) revealed three major benthic habitat descriptions which would

apply to habitats in Choctawhatchee Bay. Marginally, Choctawhatchee Bay is

fringed with a shallow sand shelf. This blends into deeper regions with

varying mixtures of sand and mud comprising the transitional zone. Lastly,

there is a broad central deepwater mud plain. Other smaller habitats,

possibly of more importance, are the grass beds and oyster beds. The grass

beds and oyster beds provide substrate for attachment, shelter, feeding and

reproduction of macroinvertebrates. Also, these areas should have a greater

species diversity than found in the three major habitats of the Bay.

Studies of the benthic macroinvertebrate communities in Choctawhatchee Ba

have been made by the Corps of Engineers in 1974 and 1976, Taylor Biological

Co., 1978*, Battelle-Columbus Lab., 1973, and Ross and Jones, 1979. Ross and

Jones, 1979, found sixty four species at eighteen stations in six primary





*Radcliff Company, Mobile, Alabama, removed eight million cubic yards of

oyster shell from the sediments of Choctawhatchee Bay from 1946 to 1970. In

an effort to extend this dredging activity, Taylor Biological Company, 1978,

performed a study to assess dredging activities in the Bay.









habitats including shallow and deep water sand and mud communities, as well

grass beds and a deep water red algae community. The Florida Department of

Regulation (unpublished data) has periodically sampled the benthos above Pin

Point and found 110 species of benthic invertebrates thus far. Collard, 197

and Pastula, 1968, both suggested that benthic invertebrates were least abun

dant toward the eastern end of the Bay. Pastula, 1967, attributes the

decrease to reductions of both salinity and dissolved oxygen toward the

eastern end of Choctawhatchee Bay. Most of the information concerning the

benthos is centered in deeper waters of the Bay. Further studies should

investigate grass beds, oyster reefs and the near shore shelf around the Bay.

In studies of deep water stations, both Taylor Biological Co., 1978, and

Battelle-Columbus Lab., 1978, found polychaete worms to be the most common

organisms in both numbers and species diversity. All previous investigation!

concerning the benthos in Choctawhatchee Bay have noted a general paucity of

benthic invertebrates. This paucity has been blamed on the extreme environ-

mental stress at deep water stations in the Bay, resulting from salinity

changes, long term low dissolved oxygen concentrations and high sedimentation

rates. This stress is particularly evident in the summer and early fall. In

LaGrange Bayou, the U.S. Corps of Engineers, 1973, found freshwater bivalves

and crustacea to comprise the dominant fauna.


Fisheries


The general consensus concerning sport and commerical fishing in

Choctawhatchee Bay is that it has been on the decline since the late 1960's.

Prior to the late 1920's, the Bay existed as a limited access embayment with









only slight tidal exchange resulting in slightly brackish water (Okaloosa

Economic Development Council, 1978). In the years prior to the formation of

East Pass, Santa Rosa Sound should have played a much more important role

in the flushing of Choctawhatchee Bay than it does at present. With increased

salt water intrusion into the Bay due to the opening of East Pass, and the sub-

sequent maintenance of the Pass (U.S. Army Corps of Engineers, 1975), the spe-

cies of fish in the Bay, particular in the western Bay, should have tended

toward more marine species. In the late 1960's, bridge fishermen from

Okaloosa County reported catching red snapper in Cinco Bayou and Garnier

Bayou. However, since then many local fishermen feel that both numbers of

fish caught have declined and that some species such as red snapper are

completely absent where they were once common. Barret, Daffin and Carlin,

1979, make similar connotations.

Irby, 1974, discusses sea trout (Cynosion nebulosus) populations in

Choctawhatchee Bay. Many Bay sports fishermen attribute declining catches of

sea trout to over-fishing by commerical fishermen (Irby, 1974) and more

recently, declining grass beds (personal communication). However, Irby, 1974,

concludes that without earlier baseline data such reductions cannot be found

and that survey results do not indicate exploitation by commercial fishermen.

Fish kills occurring in both Garnier Bayou and Rocky Bayou from 1972 to

1975, are the result of low flushing rates, high temperatures and low

dissolved oxygen concentrations. The Fish and Wildlife service initiated a

striped bass (Morone saxtilis) stocking program and a basin wide species survey

in 1968 (U.S. Fish and Wildlife Service, 1973). An associated environmental

study suggested that heavy sedimentation from Choctawhatchee River could be








detrimental to fisheries in the Bay (U.S. Fish and Wildlife Service, 1973).

The striped bass stocking program was discontinued in 1975 due to budget cut

(Northwest Florida Water Management District, 1980); however, the stocking

program was showing signs of success with striped bass found to be spawning

Choctawhatchee River in the spring of 1975 (U.S. Fish and Wildlife Service,

1975).


Submerged Aquatic Vegetation


Submerged aquatic vegetation is an important component of estuaries. Th:

vegetation provides food and shelter to many estuarine organisms, as well as

spawning and nursery grounds for both resident and non-resident species.

Chemically, the grass beds in an estuary aid in oxygenation of the water and

act as buffers to nutrients and toxic metals. Submerged aquatic vegetation

can also play an important role in nutrient cycling within an estuary.

Many local residents have suggested that grass beds in Choctawhatchee Ba>

are declining in acreage. Suggestions as to reasons include increased

turbidity, adverse weather conditions, increased activity by commercial net

fisherman and testing of the herbicide, agent orange on the northern shores o

Choctawhatchee Bay. Without good documentation of the historical and existing

grass beds, no conclusions can be made as to the actual demise, if any, of th

grass beds in Choctawhatchee Bay. Figure 4-20 depicts grass beds in

Choctawhatchee Bay. These beds are composed from both McNulty, Lindall and

Sykes, 1971, and drawings from 1973 aerial photographs covering the shoreline

of Choctawhatchee Bay. The prevalent estuarine seagrass in Choctawhatchee Ba:

is Ruppia maritina. McNulty, Lindall and Sykes, 1971, found Choctawhatchee








Bay to contain 3,092 acres of submerged aquatic vegetation and 2,816 acres of

tidal marsh grasses (Figure 4-20).

The decline of existing grass beds within many of the estuaries in the

Gulf of Mexico and on the Atlantic Coast is well documented (U.S. Environmental

Protection Agency, 1975; EPA, 1981). The demise has been due to both natural

causes and cultural disturbances. Turbidity caused by weather disturbances,

increased fluvial sediment loads, increased boat traffic and dredging opera-

tions is thought to severely limit the resources required for productive grass

beds (EPA, 1981). EPA, 1975, found dredge and fill operations to destroy

existing grass beds by excessive siltation. Other factors thought to cause

the decline of sumberged aquatic vegetation include natural diseases, tem-

perature and salinity trend changes, excessive nutrients, herbicides and

excessive petrochemicals (U.S. Fish and Wildlife Service, 1978). The author

has also observed significant damage to seagrass beds due to careless opera-

tion of gill nets.














SEDIMENTS



Sediment Characterization



Choctawhatchee Bay is fringed with fine to medium sized, well washed

quartz sand. The sand extends from the mean high water level to the six to

eight foot contour where the bottom drops sharply into a transition zone of

sand and silt. From Battelle-Columbus Laboratories, 1973, for Grayton Beach

and eastern Choctawhatchee Bay and Goldsmith, 1966, for the entire Bay, this

sand marginal shelf grades into a deep water zone composed of clay and silt.

The sedimentology study conducted by Goldsmith, 1966, further indicates a dif-

ferent bottom composition in the far western end of the Bay where the bottom

is primarily composed of relict quartz sand. The western Bay lacks the large

clay deposits found in the eastern and central portions of the Bay. The dif-

ference may be due to the erosion of existing shorelines on the northern and

northeastern shores.

The topology of Choctawhatchee Bay lends itself to the formation of an

expansive sediment trap, due to the shallow pass to the Gulf of Mexico rela-

tive to the depth of the Bay. The clay deposits in the Bay are suspected to

have originated in sediment loading from Choctawhatchee River (Goldsmith,

1966). The clay and silts from the river discharge tend to flocculate and

settle as the freshwater carrying them encounters increasingly greater sali-





49














SEDIMENTS



Sediment Characterization



Choctawhatchee Bay is fringed with fine to medium sized, well washed

quartz sand. The sand extends from the mean high water level to the six to

eight foot contour where the bottom drops sharply into a transition zone of

sand and silt. From Battelle-Columbus Laboratories, 1973, for Grayton Beach

and eastern Choctawhatchee Bay and Goldsmith, 1966, for the entire Bay, this

sand marginal shelf grades into a deep water zone composed of clay and silt.

The sedimentology study conducted by Goldsmith, 1966, further indicates a dif-

ferent bottom composition in the far western end of the Bay where the bottom

is primarily composed of relict quartz sand. The western Bay lacks the large

clay deposits found in the eastern and central portions of the Bay. The dif-

ference may be due to the erosion of existing shorelines on the northern and

northeastern shores.

The topology of Choctawhatchee Bay lends itself to the formation of an

expansive sediment trap, due to the shallow pass to the Gulf of Mexico rela-

tive to the depth of the Bay. The clay deposits in the Bay are suspected to

have originated in sediment loading from Choctawhatchee River (Goldsmith,

1966). The clay and silts from the river discharge tend to flocculate and

settle as the freshwater carrying them encounters increasingly greater sali-





49








nity gradients. Previous studies found salinity and pH to increase in watei

moving from the mouth of Choctawhatchee River toward East Pass (Goldsmith,

1966; Ritchie, 1961), and the combination of these two factors cause

increasingly greater sedimentation (Postma, 1967). In addition, the salinit

density gradient should cause a gradient of large particle size sediments t(

finer sediments from Choctawhatchee River to the deep water region above Ea!

Pass. Flocculation of sediments is greatest at the salinity gradients foun(

at minor upwelling sites in Choctawhatchee Bay. Goldsmith, 1966, found thi!

to be evident with increased clay deposits at suspected upwelling sites norl

of Hogtown Bayou and northeast of East Pass (Figure 4-21). An examination (

Figure 4-9 depicting bottom depth confirms these sites as sites of potential

upwelling.

A review of sediment data from the U.S. Environmental Protection Agency,

1975, the U.S. Corps of Engineers, 1975, and the U.S. Corps of Engineers,

1976, suggests increasingly greater organic constituents with finer silts ar

clay in the sediment. In Choctawhatchee Bay this results in increasingly

greater organic component concentrations in the deeper sediments and in turr

increased reduction/oxidation redoxx) from the east to the central region oi

the Bay. In support, Goldsmith, 1966, found the redox potential to increase(

with increasing depth. The high redox potential facilitates and prompts lot

alkalinity and low dissolved oxygen concentration. This both enhances the

growth of sulfate bacteria and restricts the benthic fauna. Low pH values

from the freshwater inflow causes calcium carbonate to go into solution

(Goldsmith, 1966; Postula, 1967). Calcium carbonate concentrations are higl

in Choctawhatchee Bay than in other bays along the Florida Panhandle with h:


















































....... ... -. ......... ORENO POINT


.. NAUTICAL MILES

YARDS


Figure 421 Bottom Types in Choctawhatchee Bay.

Figure 4-?1: Bottom Types in Choctawhatchee Bay.








percentages of clay in the sediments. However, in areas of greater silt and

sand composition the trend is reversed. Foraminiferal deposits (Figure 4-10

found by Pastula, 1967, are in regions where higher saline water tongues can

buffer the pH, thus decreasing the dissolution of calcium carbonate. The

pockets of calcium carbonate in bottom sediments correspond directly to sali

pockets of water and large deposits of clay in the sediment (Goldsmith, 1966

Other deposits of calcium carbonate in the form of oyster shells have been

located and dredged by Radcliff, Inc. (Taylor Biological Co., 1978). Taylor

Biological Co., 1978, found extensive beds of oyster shell lying 4 to 6 feet

beneath fine sediments and sand about 0.5 miles off the northern shores of tl

central bay. These deposits indicate a previous change of nature of the

character of Choctawhatchee Bay possibly due to the formation of Morino Poin'

about 3000 B.P. Morino Point is thought to have been formed by a westward

longshore drift in the Gulf of Mexico blocking easy exchange of salt water ai

fresh water in the Bay.


Sediment Chemistry


Choctawhatchee Bay was found to have higher organic nitrogen and carbon

the sediment than many other Northwest Florida bays (Table 4-1). Sediment

phosphorous concentrations ranged from lows of 13.0 mg/kg to 78.75 mg/kg (U.!

Army Corps of Engineers, 1976) to a mean for the central Bay of 350.7 mg/kg

(U.S. Environmental Protection Agency (EPA), 1975). Phosphorous concentratic

were greatest in the eastern portion of the Bay. Excluding Alagua Bayou wit-

residual sawdust sediments and the mouth of Choctawhatchee River stations,

EPA, 1975, found organic nitrogen and carbon to correlate well with depth.














Table 4-1: Total phosphorous, organic nitrogen, and organic carbon in

mud sediments samples from five northwest Florida bays.




Location Number Mean Mean Mean
of Total Organic Organic
Samples Phosphorous Nitrogen Carbon
(mg/g) (mg/g) (mg/g)

--------------------------------------------------------------------

Escambia Bay 19 248.8 0.57 31.4

East Bay 5 195.6 0.59 33.7

Panama City Bay 9 468.9 1.18 58.6

Choctawhatchee Bay 6 350.7 1.60 59.0

Pensacola Bay 1 468.0 0.71 35.4



Source: U.S. Environmental Protection Agency, 1975.




















53









The U.S. Army Corps of Engineers, 1976, found stations in Santa Rosa Sound

near the Ft. Walton Beach sewage treatment plant (STP) and near the

Intercoastal Waterway Canal mouth in eastern Choctawhatchee Bay to exceed

recommended standards of 1,000 mg/kg of nitrogen in the sediment by 150 to !

percent.

Volatile organic compounds in the sediments of Choctawhatchee Bay were

sampled by the U.S Environmental Protection Agency (EPA), 1975, and the U.S.

Army Corps of Engineers, 1976. EPA, 1975, found deep water sediments to cor

tain from 8.42 to 24.52 percent volatile organic. The U.S. Army Corps of

Engineers, 1976, found percent volatile organic to range from 0.35 t 1.2 pe

cent in sandy locations, 3.83 percent in clay sediments and from 17.04 to

23.37 percent in silty sediments. Percent volatile organic in silty sedi-

ments exceeded the criteria of 6 percent maximum volatile organic (Water

Quality Criteria, 1972), in all cases. The U.S. Army Corps of Engineers,

1976, also found high biological oxygen demand and chemical oxygen demand

(COD) at silty sediments stations near the mouth of Choctawhatchee Bay. In

1974, in eastern Choctawhatchee Bay, along with Intracoastal Waterway, the C

exceeded recommended levels of 50 mg/kg *103 (Water Quality Criteria, 1972),

for coastal waters. Clay sediments had a COD of 27.35 mg/kg* 103, while san

bottom stations had a COD ranging from 2.09 to 6.21 mg/kg *103. Sediment

biological oxygen demand was found to be much higher in central Choctawhatch

Bay than in other Northwest Florida Bays (U.S. Environmental Protection Agen

1975).








percentages of clay in the sediments. However, in areas of greater silt and

sand composition the trend is reversed. Foraminiferal deposits (Figure 4-10

found by Pastula, 1967, are in regions where higher saline water tongues can

buffer the pH, thus decreasing the dissolution of calcium carbonate. The

pockets of calcium carbonate in bottom sediments correspond directly to sali

pockets of water and large deposits of clay in the sediment (Goldsmith, 1966

Other deposits of calcium carbonate in the form of oyster shells have been

located and dredged by Radcliff, Inc. (Taylor Biological Co., 1978). Taylor

Biological Co., 1978, found extensive beds of oyster shell lying 4 to 6 feet

beneath fine sediments and sand about 0.5 miles off the northern shores of tl

central bay. These deposits indicate a previous change of nature of the

character of Choctawhatchee Bay possibly due to the formation of Morino Poin'

about 3000 B.P. Morino Point is thought to have been formed by a westward

longshore drift in the Gulf of Mexico blocking easy exchange of salt water ai

fresh water in the Bay.


Sediment Chemistry


Choctawhatchee Bay was found to have higher organic nitrogen and carbon

the sediment than many other Northwest Florida bays (Table 4-1). Sediment

phosphorous concentrations ranged from lows of 13.0 mg/kg to 78.75 mg/kg (U.!

Army Corps of Engineers, 1976) to a mean for the central Bay of 350.7 mg/kg

(U.S. Environmental Protection Agency (EPA), 1975). Phosphorous concentratic

were greatest in the eastern portion of the Bay. Excluding Alagua Bayou wit-

residual sawdust sediments and the mouth of Choctawhatchee River stations,

EPA, 1975, found organic nitrogen and carbon to correlate well with depth.















Table 4-2: Percent of mud in sediments (top 15 cm.) from central basins

of northwest Florida bays.*



Bay Number of Mean Percent Percent
Stations Depth Mud Clay
(m) (%) (%)


Escambia 17. 3.3 91.36 50.63

East Bay 4. 4.2 88.34 64.69

Pensacola Bay 1. ** 8.4 97.47 60.05

Choctawhatchee Bay 6. 5.2 98.00 73.93

Bays at Panama City 7. 6.3 91.43 62.19

Blackwater Bay 1. 2.6 94.78 70.30



Data generated from samples that have either greater than 80% mud or
greater than 50% clay.

** Station near a recent channel dredging project and probably this station
dredged in the past year.

Source: U.S. Environmental Protection Agency, 1975.

















55


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