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Phytoplankton Community Structure in Tampa Bay, Florida,USA

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Phytoplankton Community Structure in Tampa Bay, Florida,USA
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BADYLAK, SUSAN
Copyright Date:
2008

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Subjects / Keywords:
Algae ( jstor )
Bays ( jstor )
Cyanobacteria ( jstor )
Diatoms ( jstor )
Estuaries ( jstor )
Nutrients ( jstor )
Phytoplankton ( jstor )
Salinity ( jstor )
Species ( jstor )
Taxa ( jstor )
Tampa Bay ( local )

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University of Florida
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University of Florida
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Copyright Susan Badylak. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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6/30/2006

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PHYTOPLANKTON COMMUNITY STRUCTURE IN TAMPA BAY, FLORIDA U.S.A. By SUSAN BADYLAK A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2005

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Copyright 2005 by Susan Badylak

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iii ACKNOWLEDGMENTS The author would like to thank Dr. Ed ward Phlips for his support and the opportunity to complete my thesis. His insp iration and incredible knowledge on the topic of algae have allowed me to expand my horizons. I would also like to thank my committee members Dr. Tom Crisman and Dr. Ma rk Brenner. Their suggestions have enhanced the scope of my thesis.

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iv TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iii LIST OF TABLES...............................................................................................................v LIST OF FIGURES...........................................................................................................vi ABSTRACT......................................................................................................................v ii CHAPTER 1 INTRODUCTION........................................................................................................1 2 MATERIALS AND METHODS.................................................................................4 Study Site..................................................................................................................... .4 Field Procedures...........................................................................................................6 Analytical Methods.......................................................................................................6 Phytoplankton analysis.................................................................................................6 3 RESULTS.....................................................................................................................9 Physical and Chemical..................................................................................................9 Phytoplankton Composition.......................................................................................10 Site 1......................................................................................................................... ..25 Site 2......................................................................................................................... ..26 Site 3......................................................................................................................... ..28 4 DISCUSSION.............................................................................................................31 Spatial and Temporal Trends......................................................................................31 Models for Phytoplankton succession........................................................................32 Historical Perspective.................................................................................................36 LIST OF REFERENCES...................................................................................................38 BIOGRAPHICAL SKETCH.............................................................................................44

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v LIST OF TABLES Table page 3-1 Ranges and mean values for salinity, temp erature, secchi, chl a, total nitrogen (TN), and total phosphorous (TP), at th ree sites in Tampa Bay over a one year sampling period........................................................................................................10 3-2. Phytoplankton species that occurred in more than three sample events during Winter Spring Summer or Fall (W, SP, S, F)...........................................................14 4-1 Definitions of the three life form st rategies (after Reynolds and Smayda 1998)........33

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vi LIST OF FIGURES Figure page 2-1 Location of sampling sites in Tampa Bay Estuary........................................................5 3-1. Biovolume of dinoflagellates, diatom s, cyanobacteria and other phytoplankton cells at three sampling sites in Tampa Bay.............................................................11 3-2 Numerical abundances of dinoflagellates, diatoms, cyanobacteria and other cells at three sampling sites in Tampa Bay..........................................................................12 3-3. Numerical abundances of dinoflagell ates, diatoms, and other phytoplankton groups at three sampling sites in Tampa Bay...........................................................13 3-4 Distribution of Dactyliosolen fragiilissimus at three sites in Tampa Bay...................22 3-5 Distribution of Skeletonema costatum at three sites in Tampa Bay...........................23 3-6. Distribution of Pyrodinium bahamense var. bahamense at three sites in Tampa Bay...........................................................................................................................2 4 3-7. Distribution of Pseudo-nitzschi a spp. at three sites in Tampa Bay..........................28 4-1. Annual successional pattern of phytoplankt on life strategy components C-S-R in relation to nutrient accessi bility and water column mixing (After Smayda and Reynolds 2001)........................................................................................................33

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vii Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science PHYTOPLANKTON COMMUNITY STRUCTURE IN TAMPA BAY, FLORIDA, USA By Susan Badylak December 2005 Chair: Edward Phlips Major Department: Interdisciplinary Ecology The objectives of this study were to de termine if sub basins within Tampa Bay Estuary support different phytoplankton comm unities and biomass potential and if current observations of phytoplankton commun ities showed differences from historical accounts. Thirty collection events took pl ace from April 2002 to April 2003 at three sites. Site 1 was in the lower estuary, tida lly mixed and had short water residence time. Site 2 was in a mixing zone between the uppe r and lower estuary and site 3 was in Old Tampa Bay, part of the upper estuary, ch aracterized by long water residence time and decreased salinity. Dactyliosolen fragilissimus was numerically abundant during all four seasons at the tidal influenced site. Skeletonema costatum was a numerically abundant diatom during all four seasons in the mixing zone and Pseudo-nitzschia spp. had its highest concentrations at this site. Pyrodinium bahamense var bahamense was the numerically abundant dinoflagellate in Ol d Tampa Bay during summer and fall. Foremost observations of picoplankton cya nobacteria completed dur ing the current study

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viii indicate their numerical domina nce at all sites but due to the small size were infrequently dominant in terms of biomass. Diatom bioma ss was greatest at the tidally influenced site and mixing zone between lower and upper estu ary. Dinoflagellate biomass was greatest in Old Tampa Bay. Historical reco rds indicate Skeletonema costatum as the dominant diatom throughout the bay and observations fr om this study support that observation. Gonyaulax balechii had abundant records in historical data but was rarely observed in current data. Pyrodinium bahamense var bahamense, the dinoflagellate with high concentrations in the upper es tuary, has no reported historical concentrations in the bay. Observations from this study support the obj ectives that sub basins within the bay maintain different phytoplankton groups and biomass potential and current observations showed differences fr om historical accounts

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1 CHAPTER 1 INTRODUCTION Estuaries are among the most productiv e aquatic ecosystems and are often characterized by rich phytoplankton asse mblages (Odum et al.1974). One of the fundamental determinants of estuary st ructure is the composition, abundance, and diversity of phytoplankton (Smayda 1978, Richar dson and Jorgensen 1996). Spatial and temporal differences in phytoplankton communities have direct effects on the overall function of estuaries and can a ffect the role of the estuary as a natural resource from a human perspective (Nixon 1995, Cloern 2001, Greening and Elfring 2002). Many researchers have raised serious concerns about the rapid an d dramatic increase in human inputs to the coastal marine environment ove r the past century and how these inputs may negatively impact the integrity of estu arine ecosystems (Nixon 1995). Observed increases in the intensity a nd frequency of phytoplankton bloo ms of toxic or otherwise harmful algal species have direct implications for the sustaina bility of coastal ecosystems as recreational and fisheries resour ces (Anderson 1989, Smayda 1990, Hallegraeff 1993, Phlips et al. 2003). Even in cases where blooms are dominated by non-toxic species, their impact on water clarity, dissolved oxygen, and the structure of food webs can cause significant changes in the structure and function of ecosystems. Tampa Bay, located along the densely populated west coast of central Florida, is a large subtropical estuary that experienced major increases in anthropogenic nutrient, pollutant, and sediment loads during the early to mid 1900s, but has since undergone serious restoration efforts (T BNEP 1996,). Original source s of water quality degradation

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2 included poorly treated domestic sewage, i ndustrial wastes from phosphate mines, and citrus canneries (Galstoff 1954). From 1950-1980, there was a 40% die-off of seagrass beds in the estuary attributed to dredging activities, resuspension of sediments, and nutrient-induced algal blooms (TBNEP 1996) . In 1987, the National Estuary Program (NEP) was created to identify, restore, a nd protect nationally significant estuaries (Beatley et al. 2002). Tampa Bay was selected as an NEP site because of the importance to the ecology of the west coast of Flor ida and the rapid decline in water quality experienced by the bay in the mid 1900s. Amon g the major issues raised by the NEP was the role that changes in the phytoplankton co mmunity played in the negative impacts observed in the estuary, particularly loss of water clarity and die-offs of seagrass communities. The goal of this study was to describe current phytoplankton community structure of Tampa Bay, taking into accoun t the spatial heterogeneity of habitats existing within sub regions of the bay. It also provided an opportunity to compare the current phytoplankton community with prior historical accounts. Historical descriptions of phytoplankton communities along the west coast of Florida began in the 1950s. In the 1960s, outbreaks of the toxic red tide species Karenia brevis were observed in Tampa Bay and Gulf of Mexico (Dragovich and Kelle y 1964, Steidinger et al. 1967, Saunders et al. 1967, Steidinger and Williams 1970). Deta iled studies of phytoplankton community structure were carried out during the late 1950s, and th e 1960s and 1970s before the inception of the Tampa Bay National Estuar y Program ( Marshall 1956, Steidinger and Williams 1970, Steidinger 1971, Steidinger and Balech 1977, Steidinger et al.1980, Turner 1972, Gardiner1983).

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3 Two working hypotheses for the study were 1) sub-basins within the bay support different phytoplankton groups and biomass and 2) the cu rrent phytoplankton community differs from historical communities. .

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4 CHAPTER 2 MATERIALS AND METHODS Study Site Tampa Bay is located in central Florida adja cent to the Gulf of Mexico. It has an average depth of 3.5m, a shoreline length of 1,454 km, with mixed tides, and an average tidal range of 0.7 m. (Goodwin 1989). The Tampa Bay watershed is highly developed with a population exceeding two million people a nd a mixture of land-uses including of urban, suburban, agriculture, mining and light industry. Biogeographically, Tampa Bay is located in the transition between the warm temperate and subtropic climate (Johnson and Barbour 1990). The period of this st udy, April 2002April 2003, was characterized by high rainfall associated with an El Nio event. Tampa Bay has several distinct ecological regions, that differ in watershed inputs and tidal mixing characteristics (Lewis et al. 1989). Three sampling sites were included in the study to capture part of the ecological he terogeneity of the bay (Figure 2-1). Site 1 (27 35. 758 N and 82 38. 127 W) was located in lower Tampa Bay near the confluence with the Gulf of Mexico. This site had both greatest influence from tidal mixing and the shortest water residence times . Site 2 (27 53. 400 and 82 32. 675) was located near the middle of the bay where water from the upper and lower bay mix to create a mixing zone (Bendis 1999). Site 3 (27 59. 644 N and 82 39. 847 W) was located in the northern bay, a region known as Old Tampa Bay. This area receives water from several small tidal creeks. Vehicular causeways and shoals restrict tidal water exchange in Old Tampa Bay, resulting in long water residence times (Burwell 2001).

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5 Figure 2-1 Location of sampling sites in Tampa Bay Estuary 3 2 1

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6 Field Procedures The three sites were sampled from April 2002 to April 2003, roughly twice a month. Water samples were collected for phytoplankton identification, enumeration, and chlorophyll determination. On site measuremen ts were also made of physical/ chemical parameters. Total nitrogen and total phosphor us concentrations we re obtained from the Hillsborough County Environmental Protecti on Agency (HCEP), which carried out complimentary monthly sampling activities thro ughout the bay during th e course of this study. Water samples were collected with an integrating tube that captures water from the surface to within 0.1 m of the bottom to avoid bi as associated with ve rtical stratification of water masses and associated plankton. Phytoplankton samples were preserved with Lugols solution. Aliquots of sample water we re filtered through a Gelman A/E glass fiber filters on site to collect samples for ch lorophyll determination. Filters were placed on ice in the dark for transport to the la b, where they were immediately frozen for subsequent chlorophyll a determination. Salinity and temp erature were measured with a Hydrolab Quanta. Secchi disk depth was dete rmined as a measure of light transmission. Analytical Methods Chlorophyll a on filters was ex tracted with 95% ethanol (Sartory and Grobbelaar 1984) and measured using a Hitachi U2000 dual beam spectrophotometer according to Standard Methods (APHA 1989). Phytoplankton analysis Fluorescence microscopy was used to e numerate picoplanktonic cyanobacteria (Fahnenstiel and Carrick 1991). Subsamples of water were filter ed through a 0.2m pore Nucleopore filters that was then mounted betw een a microscope slide and cover slip with

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7 immersion oil. They were then frozen a nd counted within 72 hours of sampling using a Nikon research microscope equipped with autofluorescence (green light 530-560nm excitation and >580nm emission). Owing to the inherent difficulty in identifying certain species of picoplanktonic cyanobacteria us ing standard microscopy, some taxa were given a letter designation. These include Cyanobacterium A, a phycocyanin rich spherical unicell ~ 2-3 m in diameter, and Cyanobacterium B, a phycoerythrin rich spherical unicell ~ 2-3 m in diameter. Nu merical abundance of cyanobacteria cells was determined by counting a minimum of fi ve ocular micrometer grids at 1000x magnification. The number of grids counted wa s adjusted to cell density. Counts were completed upon reaching a minimum of 100 cells. Routine phytoplankton analysis used the Utermohl method (Utermohl 1958). Lugols preserved samples were settled in 19 mm inner diameter cylindrical chambers. Phytoplankton cells were iden tified and counted at 400x and 100x magnification with a Leica phase contrast invert ed microscope. At 400x magni fication, a minimum of 100 cells of a single taxa and 30 grids were c ounted. If 100 cells of a single taxon were not reached within 30 grids counting would conti nue until 100 cells were observed or until 100 grids were counted, whichever came fi rst. At 100x magnification a total bottom count of the settling chamber was c ounted for taxa larger than 30m. In addition to the standard protocols used for taxonomic identif ication, several taxa required special handling. Protoperidinium cells were identified by cell size, body contour, and shape. In the case of the sma ll diameter spherical uni cellular algae (<3m) observed at Site 1 in the spring, a tentative identifi cation of Chlorella /Nannochloris was used in the absence of a more detailed intr acellular structure analysis. These cells were

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8 placed in a group classified as “other”. Mi croflagellates defined as marine flagellate cells less than 15m in size, excluded di noflagellates, and were placed in the group classified as “other”. Small Gymnodinium cells (<15m) were assigned size categories. Centric and unspecified pennate diatom s were put into size categories. Pleurosigma/Gyrosigma was not separated out. Differe nces in valve outline and size revealed two forms of Pseudo-nitzschia from the Nitzschia delicatissima complex. Due to lack of confirmation from SEM analysis the species were not separated. Pseudonitzschia calliantha has been previously reported from Tampa Bay (Lundholm 2003). For the purpose of broadly classifyin g phytoplankton numerical abundances, two categories were defined, 1 and 2. 1 indicates concentrations of gr eater than 100 cells ml-1 and was denoted as high. 2 indicate c oncentrations of greater than 1000 cells ml-1 and were denoted as ‘very high. Guidelines of the Intergovernmental Oceanographic Commission of Unesco (IOC 2003) and Florida Marine Research Institute (FMRI 2002) were used to identify species as potentially toxic or problematic. Refere nces used most frequently for taxonomic identification included Cupp (1943), Steidi nger and Williams (1970), Tester and Steidinger (1979), Sournia ( 1986), Ricard (1987), Hasle and Syvertsen (1996), Steidinger and Tangen (1996), and Horner (2002).

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9 CHAPTER 3 RESULTS Physical and Chemical Means and ranges for selected physical and chemical parameters are presented in Table 3-1. Basic physical and chemical va lues exhibited spatial similarities and differences at three sites where they were collected. Mean salinity values ranged from 20.1 at Site 3 in Old Tampa Bay to 28.5 at Si te 1 nearest the Gulf of Mexico. The greatest range in salinity, 15.3-32.2, was observe d at Site 3. Mean water temperature varied by less than 1 C between all of the sites and the annual range was from 12 C to 31 C. Mean Secchi depth ranged from 1.5m at Site 3 in Old Tampa Bay to 2.7 at Site 1. The largest range was observed at Site 1, from 1m to 4.5m. Mean chlorophyll a values ranged from 2.1 mg m-3 Site 1 to 8.8 mg m-3 at Site 3. Peak chlorophyll a values were highest at Site 3, reaching 52.2 mg m-3. Mean total nitrogen (TN) concentrations were similar at Sites 1 and 2 (0.64 mg L-1), and somewhat higher at Site 3, (0.79 mg L-1). Mean total phosphorus (TP) concentrations were very similar at all three sites, (0.11 to 0.12 mg L-1).

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10 Table 3-1 Ranges and mean values for salinity, temperature, secchi, chl a, total nitrogen (TN), and total phosphorous (TP), at th ree sites in Tampa Bay over a one year sampling period Site Salinity (ppt) Temp C Secchi (m) Chl a (mg m-3) TN (mg L-1) TP (mg L-1) TB1 23.2-36.5 (28.5) 12.9-30.7 (24.4) 1-4.5 (2.7) 0.04-10.3 (2.1) 0.34-1.10 (0.64) 0.08-.15 (0.12) TB2 17.4-29.2 (23.5) 13.2-31.1 (24.6) 1-3.7 (2.2) 0.08-8.4 (2.9) 0.44-0.88 (0.64) 0.09-0.15 (0.12) TB3 15.3-32.2 (20.1) 13.3-31.4 (24.8) 1-2.5 (1.5) 0.05-52.2 (8.8) 0.41-1.17 (0.79) 0.07-0.15 (0.11) Phytoplankton Composition Phytoplankton composition revealed spatial and temporal differences in biovolume and cell densities among sites. Although diatoms dominated phytoplankton biovolumes at Sites 1 and 2, dinoflagellate s were dominant in summer a nd fall at Site 3 (Figure 3-1 A, B, C). In terms of numerical abundance, picoplanktonic cyanob acteria were always dominant (Figures 3-2 A, B, C), masking te mporal and spatial patterns of numerical abundance among other phytoplankton groups (Figures 3-3 A, B, C).

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11 Figure 3-1. Biovolume of dinoflagellates, diatoms, cyanobacteria and other phytoplankton cells at three sa mpling sites in Tampa Bay. 0 5 10 15 20 25 30Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano Other 0 5 10 15 20 25 30Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano Other 0 5 10 15 20 25 30Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano OtherBiovolume, 106 m3 ml-1 A. Site 1 B. Site 2 C. Site 3 Date

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12 Figure 3-2 Numerical abundances of dinoflagellates, diatom s, cyanobacteria and other cells at three sampling sites in Tampa Bay 0 20 40 60 80 100 120 140Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano Other 0 20 40 60 80 100 120 140Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano Other 0 20 40 60 80 100 120 140Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dino Dia Cyano OtherCells / ml X 104 A Site 1 B. Site 2 C. Site 3 Date

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13 Figure 3-3. Numerical abundances of dinoflagellates, diat oms, and other phytoplankton groups at three sampling sites in Tampa Bay 0 2000 4000 6000 8000 10000 12000 14000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Other Dia Dino 0 2000 4000 6000 8000 10000 12000 14000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Other Dia Dino 0 2000 4000 6000 8000 10000 12000 14000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Other Dia DinoA. Site 1 B. Site 2 C. Site 3 Cells / ml Date

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14 Table 3-2 gives a detailed account of th e phytoplankton taxa observed at each site and basic seasonal trends in numerical abundance. Table 3-2. Phytoplankton species that occurred in more than three sample events during Winter Spring Summer or Fall (W, SP, S, F) Tampa Bay 1 Tampa Bay 2 Tampa Bay 3 DINOPHYCEAE Akashiwo sanguinea (Hiraska) Hansen & Moestrup F W F W SP F Alexandrium balechiia (Steidinger) Balech SP Amphidinium sp. SP Ceratium furca (Ehrenberg) Claparde & Lachmann SP Ceratium fusus (Ehrenberg) Dujardin SP S F Ceratium hircus Schrder W SP S F W SP S F W SP S1 F Cochlodinium citron Kofoid & Swezy SP SP Dinophysis caudata var acutiformis Kofoid & Skogsberg W SP W SP F SP S F Gambierdiscus toxicus ab Adachi & Fukuyo S Gonyaulax digitalis (Pouchet) Kofoid F W F W SP F1 Gonyaulax polygramma a Stein SP SP F Gonyaulax spinifera (Claparde & Lachmann) Diesing SP SP F Gymnodinium pulchellum 1,2 cf Larsen W

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15 Table 3-2 continued Gyrodinium fissum (Levander) Kofoid & Swezy SP SP Gyrodinium instriatum Freundenthal & Lee SP Gyrodinium spirale (Bergh) Kofoid & Swezy SP SP Gyrodinium /Gymnodinium spp <15 W S F SP S F SP F Heterocapsa niei (Loeblich) Morrill & Loeblich III S SP SP S F Heterocapsa triqueta (Ehrenberg) Stein F Karenia brevis a b S Katodinium rotundatum (Lebour) Loblich III S Katodinum glaucum (Lebour) Loblich III W SP S W SP F Ornithocercus sp SP Oxyphysis oxytoxoides Kofoid SP SP Pheopolykrikos hartmannii (Zimmerman) Matsuoka & Fukuyo SP SP Polykrikos schwartzii Btschli W W SP W SP Protoceratium spinulosum (Murray & Whitting) Schiller SP Prorocentum balticum (Lohmann) Loeblich III W W SP1 S F Prorocentrum compressum (Bailey) Abe & Dodge SP SP Prorocentrum dentatum Stein S

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16 Table 3-2 continued Prorocentrum mexicanum 1,2 Tafall S F S Prorocentrum micans Ehrenbergh W SP S F W SP S F W SP S F Prorocentrum minimum a (Pavillard) Schiller W S F S1 F Prorocentrum rostratum Stein W Prorocentrum scutellum Schrder F F Protoceratium spinulosum (Murray and Whitting) Schiller SP Protoperidinium claudicans (Paulsen) Balech W SP F Protoperidinium conicum (Gran) Balech F SP F W F Protoperidinium depressum (Bailey) Balech SP Protoperidinium divergens (Ehrenberg) Balech W F W SP F Protoperidinium leonis (Pavillard) Balech SP Protoperidinium oceanicum (VanHffen) Balech F SP SP S F Protoperidinium pellucidium Bergh SP W SP W SP F Protoperidinium punctulatum (Paulsen) Balech S Protoperidinium quinquecorn e b (Ab) Balech F SP Protoperidinium stenii (Jrgensen) Balech W

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17 Table 3-2 continued Protoperidinium subinerme (Paulsen) Loeblich III SP Pyrodinium bahamense Plate 1906 var bahamense S F S F SP1 S1 F1 Pyrophacus horologium Stein W SP S F F W SP S Pyrophacus stenii (Schiller) Wall & Dale SP S W SP S F Scrippsiella trochoidea (Stein) Loeblich III S S F W SP F Unidentified dinoflagellate A S S F BACILLARIOPHYCEAE Amphiprora sp SP SP Asterionella glacialis (Castracane) Round S S F1 S1 F Bacteriastrum spp SP S SP S S Bacteriastrum furcatum Shadbolt F Bellerochea horologicalis Von Stosch S F SP S S Centric diatoms 5-10 W1 SP S F W SP S F W SP1 S1 F1 Centric diatoms 10-50 W SP S F W SP S F W SP S F Centric diatoms 50-300 W SP S F W SP S F W SP S F Cerataulina dentata Hasle and Syversten SP Cerataulina pelagica (Cleve) Hendey W SP S F W1 SP S1 F W1 SP S Chaetoceros ceratosporus Ostenfeld SP

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18 Table 3-2 continued Chaetoceros compressus Lauder F S1 Chaetoceros costatus Pavillard SP Chaetoceros curvisetus Cleve S Chaetoceros danicus Cleve W1SP S1 W SP1 S F Chaetoceros diadema (Ehrenberg) Gran S Chaetoceros minimus (Levander) Marino, Giuffr, Monstresor & Zingone F Chaetoceros simplex Ostenfeld SP1 S F1 SP S F SP1 S F Chaetoceros subtillus Cleve SP S F S F1 SP S F Chaetoceros spp. 5 S SP S F SP F Chaetoceros spp . 10 W S F W SP S F SP S Chaetoceros spp . 20 F W SP S SP S F Corethron criophilum Castracane F1 Cylindrotheca closterium (Ehrenberg) Lewin & Reimann W SP S F W SP S 1F W SP1 S F Dactyliosolen fragilissimus (Bergon) Hasle comb nov. W1 SP1,2S1F1 W1,2 SP1S1,2 F W1 SP S F Ditylum brightwelli (West) Grunow in Van Heurck SP Guinardia delicatula (Cleve) Hasle comb nov. W SP1 S F W SP1 S Guinardia striata (Stolterfoth) Hasle com nov SP1 S F1 SP S F W SP Hemialus hauckii Grunrow in Van Heurck S F SP S 1 F SP F

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19 Table 3-2 continued Hemialus sinensis Greville SP S F F Leptocylindrus danicus Cleve SP S F S F Leptocylindrus minimus Gran F Lithodesmium sp. W F SP SP Melosira nummuloides C.A. Agardh W Navicula spp. SP S F SP F SP S F Nitzschia longissima (Brbisson, in Ktzing) Ralfs in Pritchard SP Odontella aurita SP Odontella mobiliensis (Bailey) Grunrow SP F SP S Odontella regia (Schultze) Simonsen W SP F SP F Odontella sinensis (Greville) Grunrow F Plagiogrammopis vanheurcki (Grunrow) Hasle, Von Stosch & Syvertsen SP Paralia sulcata (Ehrenberg) Cleve W SP S F W SP S Pennate diatom apical axis <25 W SP S SP S F W2 F Pennate diatom apical axis >25 <150 W SP1 S F W SP S F W SP S F1 Pleurosigma /Gyrosigma SP S F W SP S F W SP Pseudo-nitzschia spp. ( Nitzschia delicatissima complex) 1,2 W1 SP S1 F1 W SP1 S1 F1 SP S1 F2 Pseudosolenia calcaravis (Schultze) Sundstrm W SP S F W SP Rhizosolenia spp. W2 SP1,2 S1,2 F1,2 W1,2 SP1 S1 F1 SP2 S Skeletonema costatum (Greville) Cleve W SP S 1,2 F 1,2 W 1,2 SP1 S 1,2 F 1,2 SP1 S2 F

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20 Table 3-2 continued Skeletonema menzelii Guillard, Carpenter & Reimann SP SP1 Surirella spp. W Thalassionema nitzschioides ( Grunow) Mereschkowsky S F1 W1 F SP F Thalassiosira chain SP S F SP F SP1S F1 Thalasiothrix javanicum (Grunrow) Hasle comb.nov cf SP Triceratium sp SP Tropodensis sp F Diatom chain A SP CYANOPHYCEAE Ankistrodesmus convolutes Corda W1 Ankistrodesmus falcatus (Corda) Ralfs W Lyngbya sp W Lyngbya contorta Lemmermann W Merismopedia tenuissima Lemmermann W Oscillatoria spp. W1 S1 F2 SP F W1SP F2 Scenedesmus bijuga Turp W Cyanobacterium A (phycocyanin) W1 SP2 S2 F2 W2 SP2 S2 F2 W2 SP2 S2 F2 Cyanobacterium B (phycoerythrin) W1 SP2 S2 F2 W1 SP2 S2 F2 W1 SP2 S2 F2 Synechococcus longates. Nageli W2 W2 SP2 W2 SP2 F2 Unidentified 4 m filamentous F S Anabaena sp. S2 CHLOROPHYCEAE Chlorella /Nannochloris SP Unidentified microflagellates Not including dinoflagellates <5 W SP W SP S F W SP F CRYPTOPHYCEAE Unidentified cryptophyte W2 SP S F W2 SP S2 F2 W2 SP2 S2 F2

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21 Table 3-2 continued EUGLENOPHYCEAE Euglena spp F F SP F ZOOFLAGELLATES Ebriidea Hermesinum adriaticum Zacharias S F SP S F a Intergovernmental Oceanic Commissi on of UNESCO harmful algae species b Florida Marine Research In stitute harmful algae species c.f. compare 1 Denotes numerical abundances of >102 cells ml-1 2 Denotes numerical abundances of >103 cells ml-1 With respect to general spatial pa tterns of individual taxa, Dactyliosolen fragilissimus was often the most prominent phytopla nkton species at Site 1 in terms of biovolume (Table 3-2 Figure 3-4 A, B, C ).

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22 Figure 3-4 Distribution of Dactyliosolen fragiilissimus at three sites in Tampa Bay Skeletonema costatum was most often the numerically dominant diatom at all three sites (Figures 3-5 A, B, C). 0 500 1000 1500 2000 2500 3000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dactyliosolen fragilissimus 0 500 1000 1500 2000 2500 3000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dactyliosolen fragilissimus 0 500 1000 1500 2000 2500 3000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Dactyliosolen fragilissimusA Site 1 B Site 2 C Site 3 Cells / ml

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23 Figure 3-5 Distribution of Skeletonema costatum at three sites in Tampa Bay 0 1500 3000 4500 6000 7500 9000 10500 12000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Skeletonema costatum 0 1500 3000 4500 6000 7500 9000 10500 12000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Skeletonema costatum 0 1500 3000 4500 6000 7500 9000 10500 12000Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 Skeletonema costatumA. Site 1 B. Site 2 C. Site 3 Cells / ml

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24 Dinoflagellates were most diverse and abundant at Site 3 in the upper reaches of the estuary. An exceptionally high concentration of the toxic dinoflagellate Pyrodinium bahamense var. bahamense in summer and fall was the dominant feature of the phytoplankton at Site 3 (Figures 3-6 A, B. C). Additional details of the phytoplankton community are best discussed on a site-specific basis. Figure 3-6. Distribution of Pyrodinium bahamense var. bahamense at three sites in Tampa Bay

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25 Site 1 Site 1, nearest the mouth of the bay, had the lowest numerical abundance of diatoms among the three sites (Figure 3-3A), but the highest biomass of diatoms (Figure 3-1 A). This disparity is due to the relative ly large size of the di atoms common to Site 1, compared to the other two sites. Among th e individual taxa, Dact yliosolen fragilissimus had either high or very high numerical abundances in each of the four seasons (Table 3-2 and Figure 3-4A). Skeletonema costatum was also prominent at Site 1, as it appeared in high and very high abundances in both summer and fall (Table 3-2 and Figure 3-5A). Other diatom species that appear ed at densities in excess of 100 cells ml-1 were: Chaetoceros danicus , Chaetoceros simplex , Chaetoceros subtillus , Guinardia delicatula , Guinardia striata , Thalassionema nitzschioides , and Pseudo nitzschia spp. In addition, centric diatoms in the 5-30m size categor y and pennate diatoms in the large size category (25 -150 apical axis) were also observed at greater than 100 cells ml-1 in a number of samples. Dinoflagellates were pres ent at Site 1, but did not reach high or very high numerical abundances (Table 3-2). Un identified cryptophytes were numerically important throughout the sampling period and we re observed at high levels in winter (Table 3-2). Cyanobacteria were observed in all samples collected from Site 1 during the study period. Picoplanktonic cyanobacter ia A and B, and Synechococcus elongatus were always the dominant phytoplan kton taxa from a numerical pe rspective (Figure 3-2A), but due to their small size were not a major component of total phytoplankton biovolume (Figure 3-1A). Other cyanobacteria that appeared with high cell densities were Anabaena sp. and Oscillatoria sp. These genera are typica lly of freshwater origin and may result from inputs from the watershed.

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26 Potentially toxic and problematic taxa that occurred at Site 1 included the dinoflagellates Karenia brevis , Gambierdiscus toxicus , and Pyrodinium bahamense var. bahamense (Table 3-2). Karenia brevis appeared at very low dens ities, less than 0.5 cells ml-1. Gambierdiscus toxicus was observed once in very low quantities, less than 0.002 cells ml-1. Pyrodinium bahamense var bahamense , which was observed at very high densities at Site 3, was only occasionally obser ved at low densities at Site 1, perhaps as a result of drift from the upper reaches. Two taxa from the potentially toxic diatom complex Pseudo nitzschia were also observed in some samples. Pseudo nitzschia spp. was observed at densities greater than 100 cells ml-1 during the winter, summer and fall but these concentrations were low compared to other sites (Figures 3-7 A, B and C). Site 2 Site 2, in the middle of the Bay, had a lo wer diatom biovolume than Site 1 (Figure 3-1 B), but a higher numerical abundance (Figure3 -2 B). This disparity was attributable to the prominence of small celled diat oms at Site 2, such as Skeletonema costatum . S. costatum was present in all seasons at either hi gh or very high levels (Table 3-2 and Figure 3-5B). Dactyliosolen fragilissimus was also common at Site 2 with densities of greater than 100 cells ml-1 in three of four seasons (T able 3-2 and Figure 3-4 B). Cerataulina pelagica displayed high numerical levels in winter and summer. Other diatoms that appeared at high concentr ations during the sampling period were: Asterionella glacialis, Chaetoceros compressus , Chaetoceros subtillus , Corethron criophilum , Cylindrotheca closterium , Guinardia delicatula , Hemialus hauckii , Thalassionema nitzschioides , and Pseudo nitzschia spp. Dinoflagellates were observed in numerous samples, but not at high or very high levels of numeri cal abundance (Table

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27 3-2). Unidentified cryptophytes were numer ically important throughout the sampling period and were present at high concentratio ns in winter, summer and fall (Table 3-2). As observed at Site 1, picoplanktonic cy anobacteria A and B, and Synechococcus elongatus were always the numerically dominant phytoplankton taxa (Figure 3-2 B), but due to their small size were not a major component of total phytoplankton biovolume (Figure 3-1B). Potentially toxic and problematic specie s that occurred at Site 2 included the dinoflagellates Gonyaulax polygramma , Prorocentrum mexicanum , Prorocentrum minimum , Protoperidinium quinquecorne , and Pyrodinium bahamense var . bahamense , but none of these taxa were observed a high cell densities (Table 3-2). Two taxa from the potentially toxic diatom complex Pseudo nitzschia were also observed in some samples. Pseudo nitzschia spp. was observed at densities greater than 100 cells ml-1 during the spring, summer and fall with concentrations gr eater than and more frequent than other sites (Figures 3-7A, B and C).

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28 Figure 3-7. Distribution of Pseudo-nitzschia spp. at three sites in Tampa Bay Site 3 At Site 3, in Old Tampa Bay, dinoflagella tes were the dominant feature of the phytoplankton community in terms of biovolume, in sharp contrast to the dominance of

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29 diatoms at Sites 1 and 2 (Figur e 3-1 A, B and C). Site 3 also contained the greatest variety of dinoflagellates (Table 3-2). Because of its large size Pyrodinium bahamense var. bahamense dominated the phytoplankton community in summer and fall in terms of biovolume (Figure 3-1 C). It was also observed at high densities in spring (Table 3-2). Diatoms observed at high densit ies included: Ceratium hircus , Gonyaulax digitalis , Prorocentrum balticum , Prorocentrum micans and Prorocentrum minimum . Diatoms were only rarely dominant in te rms of biovolume at Site 3. The diatoms that occurred in high numerical ab undances were: Asterionella glacialis , Thalassiosira spp., Cylindrotheca closterium , Dactyliosolen fragilissmus , Cerataulina pelagica , Chaetoceros simplex , Pseudo nitzschia spp., Chaetoceros spp. in the 10 m size category, centric diatoms in the 5-10m size category a nd pennate diatoms in the <25 m and large (25-150 apical axis) size categor ies. Skeletonema costatum occurred in both high and very high abundances. Picoplanktonic cyanobacteria A and B, and Synechococcus elongatus were always the numerically dominant phytoplankton taxa as observed at Sites 1 a nd 2 (Figure 3-2 C), but due to their small size were not a ma jor component of total phytoplankton biovolume (Figure 3-1C). During the period of high cell concentratio ns of Pyrodinium there was a dramatic drop in picoplankton levels (Fi gure 3-1 C and 3-2 C). Another cyanobacterium that was observed in very high numbers was Oscillatoria sp. likely due to washout from the watershed. Unidentified cryptophytes were also observed in very high numbers during all four seasons. Potentially toxic and problematic species of interest observed at Site 3 included Pyrodinium bahamense var . bahamense , Gonyaulax polygramma , Gymnodinium

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30 puchellum c.f., Prorocentrum mexicanum , Protoperidinium quinquecorne and Prorocentrum minimum . Gymnodinium puchellum was also observed at high densities but was given a tentative I.D. until a more de tailed morphological analysis is completed. All of these taxa o ccurred with high numerical dens ities during the sampling period (Table 3-2). The exceptionally hi gh numerical abundance of Pyrodinium bahamense var . bahamense is particularly notewor thy considering recent obs ervations of its capacity to produce saxitoxin (Landsberg et al. 2002). In accordance with the tropical nature of Pyrodinium bahamense var . bahamense it was not observed in the winter. The potentially toxic diatom Pseudo-nitzschia spp was observed at high and very high numerical densities in summer and fall.

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31 CHAPTER 4 DISCUSSION Spatial and Temporal Trends Results of this study reveal major spatial and temporal differences in the structure and abundance of phytoplankton in Tampa Bay and the difference of physical factors between sites. In terms of biomass (represented as biovol ume), diatoms dominate the lower and middle regions of Tampa Bay, wh ile dinoflagellates dominate in the upper reaches of Bay, i.e. Old Tampa Bay. Tw o of the major differences between the lower/middle and the upper regions of the ba y are the relative infl uence of tidal mixing and salinity variation. The lower/middle re gion experience relatively greater tidally induced turbulence. Diatoms are favored by turbulent conditions (Margalef et al. 1979, Reynolds and Smayda 1998, Lauria et al. 1999). This conclusion is related in part to the extra energy available to maintain positiv ely buoyant non-motile diatoms in the euphotic zone and partially attributable to the excelle nt light harvesting abil ity of many of these diatom taxa. The latter characteristic allows such diatoms to sustain growth in the light restricted environment of deep ly mixed water columns. Conversely, the upper region of Tampa Bay is characterized by le ss tidally induced turbulence and long water residence times conduc ive to blooms of motile dinoflagellates like Pyrodinium bahamense var. bahamense and other euryhaline dinoflagellates. The long residence times in Old Tampa Bay also result in quick respons es to high rainfall events, such as that associated with El Nio, which lowers salinities (Schmidt 2002). Salinity variation appears to be another driv ing force behind phytoplankton succession in

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32 the upper Bay, as indicated by the eu ryhaline character of Pyrodinium bahamense var. bahamense , and other dinoflagellates and diatoms common to the upper Bay. From a temporal perspective, the subtr opical location of Tampa Bay allows for blooms of algae to occur almost year around, although the overal l highest phytoplankton standing crops occur in the warm season. Some truly tropical sp ecies, like Pyrodinium bahamense var. bahamense , occur only in the warm season. Seasonality in the appearance of the taxon is likely due to restriction of germ ination to a particular time of year (Anderson and Keafer 1987). In addi tion to temperature variation, seasonal and long-term patterns of wind velocity and ra infall probably have an influence on the dynamics of the phytoplankton community. Windy conditions in winter and spring enhance the presence of certain diatom taxa in the bay, such as large-celled centric and pennate diatoms. Periods of elevated rainfall can increase nutrient load to the bay from the watershed, thereby enhancing the potential for algal growth. Models for Phytoplankton succession The spatial and temporal patterns obser ved in the phytoplankton community of Tampa Bay can be viewed from the c ontext of models describing phytoplankton succession and distribution. As proposed by Margelef in the Mandala (Margelef 1978, Margelef et al. 1979), turbulen ce (or mixing depth) and nutrient availability form two important axes in the definition of successional and competitive interactions between phytoplankton species. The concept introduced in the Mandala was later expanded to include three functional groups of phytopl ankton, defined by Reynolds and Smayda (Reynolds and Smayda 1998, Smayda and Reynolds 2001) as ‘C’ species, ‘S’ species and ‘R’ (Table 4-1), whose successi on is dictated by the two para meters identified in the Mandala. The three species groups are favor ed under different tur bulence and nutrient

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33 Table 4-1 Definitions of the three life form strategies (after Reynolds and Smayda 1998) ‘C’ Species Small celled (biovolume <1000 m3), fast growing, high nutrient preference. ‘S’ Species Large celled (biovolume >10,000 m3), slow growing, high light preference, motile, toxic or not eaten. ‘R’ Species Intermediate size, intermediate growth rate, low light tolerance, adapted to well mixed environments. scenarios (Figure 4-1), thereby driving successional patterns in a scheme described as the ‘Intaglio’ (Reynolds and Smayda 1998). ‘R’ sp ecies, like the diatom Rhizosolenia are favored by well-mixed turbulent water columns w ith high nutrient levels because of their ability to grow efficiently under limited li ght. As the mixed-layer shrinks, light availability in the surficial layers increases , providing the needed light energy for small, fast-growing ‘C’ species like picoplanktonic cy anobacteria, to become prominent. As the pool of bioavailable inorganic nutrients b ecomes more limiting, the selective advantage shifts to the ‘S’ species, wh ich are larger, motile, slower gr owing, and capable of storing nutrients for sustained, long–term population increases. R C SNutrient AccessibilityMixing Summer DepletionStratification W i n t e r m i x i n g Figure 4-1. Annual successional pattern of phytoplankton life strate gy components C-S-R in relation to nutrient accessibility an d water column mixing (After Smayda and Reynolds 2001).

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34 Some of the major temporal and spatial patterns of phytoplankton composition observed in Tampa Bay fit into the genera l scheme of life form strategies and successional patterns outlined in the ‘Intaglio’. For example, in the lower and middle regions of Tampa Bay, high levels of tur bulence caused by tidal mixing and the presence of deep shipping channels may explain the prominence of the non-motile diatoms Dactyliosolen fragilissimus and other Rhizosolenia spp. (‘R’ species). Non-motile diatoms benefit from vertical mixing as it pr events populations from sedimenting out of the euphotic zone (Lauria 1999). D. fragilissimus also occurs in th e upper reaches of Old Tampa Bay, but primarily in the winter and early spring when wind velocities are consistently high. Winter storms are a major driving force for resuspending sediments in Old Tampa Bay (Schoellhamer 1995). Another pattern that fits the concept of the ‘Intaglio’ is the prominence of picoplanktonic cyanobacteria (‘C’ species) th roughout the bay, particularly in late spring and fall, when rainfall-induced inputs of nutri ent from the watershed heighten levels of inorganic nutrients. Similarly, the smallcelled and fast growi ng diatom Skeletonema costatum is prominent throughout the bay in spring. The morphological makeup of Skeletonema , with setae at valve margins, enhances its ability to stay in the water column even at relatively low levels of turbulence, allowing it to extend its range in to the upper reaches of the bay. The euryhaline character of Skeletonema costatum may also provide a competitive edge (Rijstenbil 1988), in th e rapidly changing salinity environment of Tampa Bay. Skeletonema costatum had its highest concentra tions in the middle of the bay between Old Tampa Bay and lower Tampa Bay. This area is where water from the upper and lower bay mix to create a mesoha line transition zone (Bendis 1999).

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35 The upper reaches of Old Tampa Bay presen t another unique set of environmental conditions that are conducive to summer bl ooms of the ‘S’ type species Pyrodinium bahamense var. bahamense (Phlips et al. 2005). Old Tampa Bay is characterized by restricted tidal mixing due to flow constric tions from causeways a nd shoals, yielding long water residence times (Burwell 2001). Un like the Hillsborough Bay region of Tampa Bay, which receives inputs from several major rivers, Old Tampa Bay is fed by small, nutrient-rich creeks. The combination of long residence times, limited turbulence, and rainfall induced pulses of nutrients from local creeks apparently provide the ideal environment for large blooms of the euryhaline dinoflagellate Pyrodinium bahamense var. bahamense . This toxic tropical species co mpletely dominated the phytoplankton community in Old Tampa Bay in late summer and early fall of 2002, reaching exceptionally high concentrations of up to 350 cells ml-1. It is noteworthy that blooms of Pyrodinium bahamense var. bahamense were also observed at sim ilar cell densities in the northern Indian River Lagoon on the east coast of Florida during the same week (Badylak et al. 2004a,2004b, Phlips et al. 2002, 2004). The northern Indian River Lagoon and Old Tampa Bay share many of the environmental characteristics conducive to such blooms, including long water residence times, shallo w depth, and inputs of water from small nutrient-rich tidal creeks (Phlips et al . 2005). Both blooms followed after a drought period that ended in the El Nino event of 2001/2002. Another factor that may enhance the potential for Pyrodinium bahamense var. bahamense in both Tampa Bay and the Indian River Lagoon is the inhibitory effect of the toxin produced by alga on zooplankton and benthic invertebrates. The toxic phyt oplankton may maintain high standing crops by

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36 reducing zooplankton grazing but such interactions are complex and site specific (Shumway 1970, Turner 1997). Historical Perspective Studies of the phytoplankton community ca rried out in the 1960s and 1970s, prior to the restoration efforts in the bay, provide an opportunity to eval uate similarities and differences with the curren t study, in the post restorati on period. One of the most apparent similarities between the two periods is the importance of diatoms in the lower and middle reaches of Tampa Bay. Species like Skeletonema costatum , which played a key role in the phytoplankton community in the 1960s and 1970s (Saunders 1967,Turner 1972) are still a dominant feature of the bay. S . costatum is a highly cosmopolitan species, a tribute to its adaptability to a wide range of environmenta l conditions. It is a euryhaline species capable of growing over a wide range of salinities (Rijstenbil 1988). This attribute gives S . costatum an advantage in Tampa Bay, where salt and freshwater mix to form mesohaline conditions (Bendis 1999). S . costatum is also a fast-growing species capable of taking advantage of the hi gh nutrient conditions in the bay. It is important to note that while the cleanup effo rts in Tampa Bay have reduced nutrient concentrations in the bay, it remains a nutri ent-rich environment w ith the potential to sustain algal blooms. It is th erefore not surprising that S . costatum has been able to retain a major role in the phytoplankt on community of Tampa Bay. The same argument could be made for pi coplanktonic cyanobacteria, which play an important role in the phytoplankton community in terms of numerical abundance. There is no mention of picoplankton cells in any hi storical accounts, but these cells may have been overlooked without the use of fluorescence microscopy.

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37 Some of the most dramatic differenc es between the current phytoplankton community and historical accounts involve dinoflagellate taxa. Dinoflagellates were reported as being abundant in the upper reaches of Old Tampa Bay in the spring (Dragovich and Kelley 1964) and winter (Turne r 1972). It is appare nt from the current study that dinoflagellates now play an importa nt role during the warm summer and early fall in the upper reaches of th e bay. Historically, the dinoflagellate Alexandrium balechii (formerly Gonyaulax balechii ) was the dominant taxon, reachi ng concentrations of 1000 cells ml-1 (Turner 1972), but it was only rarely ob served in the current study. In the current study, Pyrodinium bahamense var. bahamense was the overwhelming dominant species in the Upper Bay dur ing the peak phytoplankton biomass period of summer/fall. Pyrodinium bahamense var. bahamense was not observed in hi storical accounts of phytoplankton in Tampa Bay (Dragovich a nd Kelley 1964, Turner 1972), with the exception of a description of the species by St eidinger in 1980 (Steidi nger et al. 1980). It is not certain whether these differences re present a long-term tre nd but they do reflect an important characteristic of the phytoplankton community considering the toxic nature of Pyrodinium bahamense var. bahamense (Landsberg et al. 2002). The recent success of Pyrodinium bahamense var. bahamense may reflect some of the changes that have occurred in the bay since restoration effo rts began. As an ‘S’ species, Pyrodinium bahamense var. bahamense may be more competitive than faster growing species like Alexandrium, especially given the nutrient-limited condi tions that exist more frquently in the Bay today. The strong toxin-prod ucing characteristics of Pyrodinium bahamense var. bahamense may also provide a competitive adva ntage by reducing the potential loss of standing crop from grazing (Shumway 1970).

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38 LIST OF REFERENCES Anderson, D.M. 1989. Toxic algal blooms and red tides: A global perspective. In T. Okaichi, D.M. Anderson, and T. Nemoto (eds), Red tides: biology, environmental science and toxicology. Else vier Science, New York. Anderson, D.D. and B.A. Keafer, 1987. An e ndogenous annual clock in the toxic marine dinoflagellate Gonyaulax tamarensis. Nature 325:616-617. American Public Health Association (APHA). 1989. Standard methods for the analysis of water and wastewater, 17th Edition, American Public Health Association, Washington, D.C., USA. Badylak, S., K. Kelly and E. J. Phlips. 2004a . A description of Pyrodinium bahamense from the Indian River Lagoon, Florida, USA. Phycologia 43:653-657 Badylak, S. and E. J. Phlips. 2004b. Spa tial and temporal patterns of phytoplankton abundance and composition in a subtropical lagoon, the Indian River Lagoon, Florida, USA. Journal of Plankton Research 26:1-22. Beatley, T., D. J. Brower, and A.K. Schwab, 2002. Coastal zone management, 2nd Edition.Island Press, Washington D.C. Bendis, B. 1999. Water quality trends in Tamp a Bay. M.S. Thesis, University of South Florida, Tampa, Florida. Burwell, D.B. 2001. Modeling residence ti me: eulerian vs. langrangian. Ph. D Dissertation, University of Sout h Florida, Tampa, Florida. Cloern J. E. 2001. Our evolving conceptual model of the coastal eutrophication problem. Marine Ecology Progress Series 210:223-253. Cupp, E.E. 1943. Marine plankton diatoms of the west coast of North America. University of California Press, Berkeley, California. Day J. W., Hall C.A.S., Kemp W.M., Yan ez-Arancibia A., 1989. Estuarine ecology. Wiley Inter-Science New York, New York. Dragovich, A. and J.A. Kelly, 1964. Pre liminary observations on phytoplankton and hydrology in Tampa Bay and the immediate offshore waters In : A collection of data in reference to a red tide outbreak during 1963. Florida Marine Research Institute Microfilm. St. Petersburg, Florida.

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39 Fanning K.A., M. N. Bell, 1985. Nutrients in Tampa Bay. p.109-129 In : Proceedings of the Tampa Bay area scientif ic information symposium eds.Treat S F,. Simon J.L,. Lewis R.R III, and R.R.Wh itman R.R Jr. Fl. Sea Grant rep.65. Bellweather Press, Tampa, Florida. Fahnenstiel, G.L. and H. J. Carrick, 1992. P hototrophic picoplankton in Lake Huron and Michigan: abundance, distribution, compos ition, and contribution to biomass and production. Canadian Journal of Fisheries and Aquatic Sciences 49: 379-388. FMRI 2002. Florida Marine Reseach Institut e, HAB species subcategory of harmful algae and red tides. Available at www.floridamarineresearchinstitute.org/redtide . April 2005. Gardiner, W.E. 1983. The nannoplankton of Tamp a Bay, Florida with special reference to Gyrodinium estuariale Hulbert (Di nophyceae) Ph.D. Dissertation, University of South Florida, Tampa, Florida. Galstoff, P. S. 1954. Gulf of Mexico. Its or igins, waters and marine life. U S Fish Wildl.Ser. Bull.89 U S Fish and Wildlife Service, Washington D.C. Gilbert P.M. 1988. Primary productivity and pelagic nitrogen cycling. In nitrogen cycling in coastal marine environments eds. Bl ackburn T.H. and Sorenson J. John Wiley and Sons New York Goodwin, C.R. 1989. Circulation of Tampa Bay and Sarasota Bays. In Estevez E.D. (ed) NOAA Estuary of the month Seris No. 11 Washington D.C. Greening, H. and C. Elfring, 2002. Local, state, regional and federal roles in coastal management. Estuaries 25:838847. Haddad K. 1982. Hydrographic factors associated with west Florida toxic red blooms an assessment for satellite prediction and m onitoring. MS Thesis, Dept. Marine Science, University of South. Florida. 161pp. Hallegraeff, G. M. 1993. A review of harmful algal blooms and their apparent global rise. Phycologia 32: 79-99. Hasle, G.R. and E. Syvertsen, 1996 Marine diatoms In C.R. Tomas (ed.) Identifying marine diatoms and dinoflagellates, Academic Press, New York, New York. Horner R. A. 2002. A taxonomic guide to some common marine phytoplankton. Biopress, Bristol, England. IOC 2002. IOC taxonomic reference list of toxic algae. Intergovernmental Oceanographic Commision of UNESCO. Av ailable from: www.ioc.unesco.org/hab

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40 Johansson J.O.R. and R.R. Lewis, 1992. Recent improvements of water quality of biological indicators in Hillsborough Bay. A highly impacted subdivision of Tampa Bay, Florida. USA. International conf erence on Marine Coastal Eutrophication, Bologna, Italy March 1990. p.1199-1215. In Science of the total environment, Supplement 1992 Elesevier, Amsterdam. Johnson A.F. and M.G. Barbour, 1990. Dunes and maritime forests p. 429-48. In Ecosystems of Florida. University of Pr esses of Florida, Gainesville, Florida. Landsberg, J. H. et al . 2002. Pufferfish poisoning: widespread implications of saxitoxin in Florida. Abstracts of the 10th International Harmful Al gal Bloom Conference. October 21-26, 2002. St. Petersberg, Florida. IOC-UNESCO, Paris Lauria M.L., D.A. Purdie, J. Sharples, 1999. Contrasting phytopl ankton distributions controlled by tidal turbulence in an estuary. Journal of Marine Science 21:189-197. Lewis, R.R., R.L Whitman, 1985. A new geogr aphic description of the boundaries and subdivisions of Tampa Bay. p. 10-17. eds. S F Treat,. J.L Simon,. R.R, Lewis III and R.L. Whitman Jr. In : Proceedings of the Tampa Bay area scientific information Symposium Fl. Sea Grant report no 65. Bellweather press, Tampa Florida. Lewis R.R., P.A.Clark, W.K Fe hrings., H.S. Greening., R.O Johansson.,and R.T. Paul., 1998. The rehabilitation of the Tampa Bay estuary, Florida, USA, as an example of successful integrated coastal mana gement. Marine Pollution Bulletin . 37:468-473. Lundholm, N., Ø, Moestrup, G.R. Hasle, and K. Hoef-Emden, 2003 A study of the pseudo-nitzschia pseudodelicatissima/ cuspidata complex (Bacillariophyceae); What is P. pseudodelicatissima? Journal of Phycology 39:797-813. Malin M.A., H. W.Pearl., J. Rudek, 1991. Seasonal phytoplankton, composition, productivity, and biomass in the Neuse ri ver estuary, North Carolina. Estuarine Coastal Shelf Science. 32:609-623. Margelef, R., Estrada, M. and Blasco, D. 1979. Functional morphology of organisms involved in red tides, as adapted to decayi ng turbulence. In: Taylor, D and Seliger, H. (eds), Toxic dinoflagellates bl ooms, Elsevier, New York, pp. 89-94. Marshall H.G. 1956. Composition of phytoplankt on off the Southeastern coast of the United States. Bulletin of.Marine. Science . 21 (4):806-825. Morrison G., A. Janicki, D. Wade, J. Martin, G. Vargo, and R.Johannson 1997. Estimated nitrogen fluxes and nitrogen ch lorophyll realationships in Tampa Bay, 1984-1994. In : Proceedings of the Tampa Bay area scientific information Symposium 3 ed.Treat S F,. Tampa, Florida. Nixon, S. W. 1995. Coastal marine eutrophicat ion: A definition, social consequences and future concerns. Ophelia 41:199-220.

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41 Odum, H.T., B. D. Copeland, and E.A. Mc Mahan. 1974. Coastal ecological systems of the United States. The Conservation Foundation Press, Washington D.C. Phlips E. J., S Badylak, S.Youn, K. Kelley, 2003. The occurrence of potentially toxic dinoflagellates and diatoms in a subt ropical lagoon, the Indian River Lagoon Florida, USA. Harmful algae 3:39-49. Phlips, E. J., S. Badylak and T. Grosskopf . 2002. Factors affecting the abundance of phytoplankton in a restricted subtropical lagoon, the Indian River Lagoon, Florida, USA. Estuarine, Coastal and Shelf Science 55:385-402. Phlips, E., S. Badylak, E. Bledsoe, and M. Cichra.2005. Pyrodinium bahamense strategies in coastal environments. Marine Ecology Progress Series . submitted Reynolds, C. S. and T. J. Smayda. 1998. Prin ciples of species se lection and community assembly in the phytoplankton: Further expl orations of the Mandala. Proceedings of the VII Interna tional Conference on Harmful Al gae, Vigo, Spain, June 25-29, 1997. IOC, UNESCO Ricard, M.I. 1987. Atlas du phytoplankton ma rin diatomphycees vol 2 Editions Du Centre National De La Recherch e Scientifique, Anatole France. Richardson, K. & B. B Jorgensen, 1996. Eutr ophication, definition, history and effects. In B. B. Jorgensen and K. Richardson, Eutr ophication in coastal marine ecosystems, pp. 1-20. American Geophysical Union, Washington, D.C. Rjstenbil, J.W. 1988 Selection of phytoplan kton species in culture by gradual salinity changes. Netherlands Jo urnal of Sea Research 22:291-300. Sartory, D.P. and J.U. Garbbellar, 1984. Ex traction of chlorophyll a from freshwater phytoplankton for spectrophotometri c analysis. Hydrobiologia 114:177-187. Saunders, R.P. B.I. Birnhak, J.T. Davis, and C.L.Walquist, 1967. Seasonal distributions of diatoms in Florida inshore waters from Tampa Bay to Caxambas Pass, 19631964. A Symposium of Florida Board of Conservation, Marine Lab Professional papers series 9. St. Petersburg, Florida. Schmidt, N. and M.E. Luther, 2002. ENSO im pacts on salinity in Tampa Bay. Estuaries 25:976-984. Shumway, S. E. 1990. A review of the effects of algal blooms on shellfish and aquaculture . J. World Aquaculture Society 21: 65-104. Schoellhamer D.H. 1995. Sediment resuspension mechanisms in Old Tampa Bay. Estuarine, Coastal and Shelf Science 40:603-620. Smayda, T. J. 1989. Primary production a nd the global epidemic of phytoplankton

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42 blooms in the sea: a linkage? In E. M. Cosper, V. M. Bricel j & E. J. Carpenter (eds.), Novel phytoplankton blooms, pp. 449-484. Springer-Verlag, New York, New.York. Smayda, T.A. 1990. Novel and nuisance phytopl ankton bloomsin the sea. Evidence for a global epidemic. In E. Granéli, B. Sundström, L.Edler, and D.M. Anderson (eds), Toxic marine phytoplankton. Elsiev er Science Inc., New York. Smayda, T. J. and C. S. Reynolds. 2001. Community assembly in marine phytoplankton: application of recent mode ls to harmful dinoflagellate blooms . Journal of Plankton Research . 23:447-461. Sournia A. 1986. Atlas du phytoplankton ma rin Vol. I.Introduction, Cyanophyceae, Dictophyceae, Dinophyceae, et Radiophyceae. Centre National de la Recherche Scientifique, Paris. Steidinger, K.A. 1968 The genus Gonyaulax in Florida waters. morphology and thecal development in Gonyaulax polygramma Stein 1883. Fl Bd. Conserv. Mar. Lab Leaf Ser.. Vol. 1 Pt. 1. No 4. 5 pp. Steidinger K.A. 1971 Gonyaulax Balechii sp. nov. (Dinophyceae) with a discussion of the genera Gonyaulax and Heteraulacus. Phycologia 10(2/3): 183-187. Steidenger, K. A., J. T. Davis, J. Williams, 1967. Dinoflagellate studies on the inshore waters of the west co ast of Florida p 4-48. In : red tide studies, Pinellas to Collier Counties 1963-1966, A Symposium of Florid a Board of Conservation, Marine Lab Professional papers series 9. St. Petersburg, Florida. Steidinger K.A. and J. Will iams, 1970. Dinoflagellates: Memoir s of the hourglass cruises. Florida Dept of Natural Resources Ma rine Research laboratory Vol 2. 251 pp. Steidinger K.A. and E. Bal ech, 1977. Scrippsiella subsalsa . (Ostenfeld) comb. nov. (Dinophyceae) with a di scussion on Scrippsiella . Phycologia 16(1) 69-73. Steidinger K.A., L.S. Tester, F.J. R. Taylor, 1980. A redescription of Pyrodinium bahamense var. compressa (Bohm) stat. Nov. from Paci fic red tides. Phycologia 19(4): 329-337. Steidinger K.A. and K. Tangen, 1996 Marine Diatoms In C.R. Tomas (ed.) Identifying marine diatoms and dinoflagellate s, Academic Press, New York. Tampa Bay National Estuary Program. 1996. Ch arting the course for Tampa Bay. Tampa Bay National Estuary Program and the US Environmental Protection Agency Region IV, St. Petersburg Florida. Taylor 1987. Ecology of dinoflagellates in coastal and marine ecosystems. p In : Biology of dinoflagellates ed. F.J.R. Taylor. Blackwell, Oxford.

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43 Tester, L.A. and K.A. St eidinger, 1979. Phytoplankton In L.M. Walker and K.A. Steidinger (eds). Nearshore marine ecology at Hutchinson Island, Florida. 19711974. Florida Marine Research Publicati on 34, Florida Department of Natural Resources, St. Petersburg, Florida. Turner J. J. 1972. The phytoplankton of the Tampa Bay System, Florida. M.A. Thesis, University of South Florida, Tampa, Florida. Turner, J. T. and Tester, P. A. 1997. Toxic marine phytoplankton, zooplankton grazers,and pelagic food webs . Limnology and Oceanography . 42:1203-1214 Utermohl, H. 1958. Zur Vervollkommnung der quantitativen Phtoplankton-Methodik. Mitteilungen Internat ionale Vereinigrung fur Theoretische and Angerewandte Limnologie 9:1-38.

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44 BIOGRAPHICAL SKETCH Susan Badylak has worked for 20 years in th e field of environmental science. Her broad scope of work experience includes 17 years of taxonomic identification of phytoplankton. She has a BA in Environmental Science from the University of Florida and will be receiving her Master of Science in interdisciplinary ecology from the School of Natural Resources and Environment at the University of Fl orida in December 2005. She is currently employed as a senior biolog ist in the lab of Dr. Edward Phlips at the Department of Fisheries and Aquatic Sciences in the University of Florida. Her future job aspirations are to conti nue working with phytoplankton in Dr. Edward Phlips lab and expand her horizons in the w onderful world of algae.