Distributions of phytoplankton in Tampa Bay Estuary, USA 20022003 (original) (raw)
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Coastal, Estuarine, and Shelf Science, 2017
In the past four decades, consistent and coordinated management actions led to the recovery of Tampa Bay, FL (USA) e an estuary that was declared dead in the 1970s. An exception to this success story is Old Tampa Bay, the northernmost subestuary of the system. Compared to the other bay segments, Old Tampa Bay is characterized by poorer water quality and spring and summer blooms of cyanobacteria, pico-plankton, diatoms, and the saxitoxin-producing dinoflagellate Pyrodinium bahamense. Together, these blooms contribute to light attenuation and lagging recovery of seagrass beds. Yet, studies of phyto-plankton dynamics within Old Tampa Bay have been limited e both in number and in their spatiotem-poral resolution. In this study, we used field sampling and continuous monitoring to (1) characterize temporal and spatial variability in phytoplankton biomass and community composition and (2) identify key drivers of the different phytoplankton blooms in Old Tampa Bay. Overall, temporal variability in phytoplankton biomass (using chlorophyll a as a proxy) and community composition surpassed spatial variability of these parameters. We found a base community of small diatoms and flagellates, as well as certain dinoflagellates, that persisted year round in the system. Seasonally, freshwater runoff stimulated phytoplankton growth, specifically that of chlorophytes, cyanobacteria and other dinoflagellates – consistent with predictions based on ecological theory. On shorter time scales, salinity, visibility, and freshwater inflows were important predictors of phytoplankton biomass. With respect to P. bahamense, environmental drivers including salinity, temperature and dissolved nutrient concentrations explained ~24% of the variability in cell abundance, indicating missing explanatory parameters in our study for this taxon, such as cyst density and location of cyst beds. Spatially, we found differences in community tra-jectories across northesouth and westeeast gradients, with the northernmost sampling station being the most unique in the region. This work contributes to the knowledge of phytoplankton biomass and community composition in Tampa Bay by generating spatially and temporally rich phytoplankton community and environmental data for the Old Tampa Bay subestuary. Moreover, it enhances our understanding of bloom drivers and provides recommendations for ecosystem management. Specifically, our findings support continued nutrient reduction measures as a way to mitigate seasonal blooms of diatoms, cyanobacteria and chlorophytes, but not necessarily blooms of P. bahamense. Prediction and mitigation of P. bahamnese blooms should incorporate first order drivers such as cyst location and abundance.
Maryland Coastal Bays (MCBs) have undergone changes in water quality in the past two decades due to nutrient enrichment but the composition and dynamics of the phytoplankton community have not been adequately described. Microscopic counts and photosynthetic pigments of samples collected monthly in 2012 at selected sites in MCBs that differed with regard to the degree of anthropogenic impacts were examined. Sixty-three (63) phytoplankton genera were recorded, of which 40 species are being reported for the first time in the Bays. Among the dominant species were Dactyliosolen fragilissimus (Bacillariophyta), Paulinella ovalis (Cercozoa) and Cryptomonas sp. (Cryptophyta). Bloom densities of Heterocapsa rotundata (Miozoa), which previously had not been reported in the Bays, were observed bay-wide in December, particularly at the mouth of St. Martin River. Diatoms dominated (>40%) the phytoplankton community in winter and decreased in spring (<40%), while Cercozoa and microphytoflagellates (MPF) co-dominated in summer (July). From August to October, diatoms dominated with maximum contributions from an unidentified small (<10 µM) centric species and co-dominated the assemblage with cryptophytes in late fall (November). Canonical correspondence analysis indicated that diatoms were favored by high salinity and total dissolved phosphorus (TDP), cercozoans and chlorophytes by total dissolved nitrogen (TDN) and cryptophytes by dissolved organic carbon. The spatial and seasonal differences in the composition of phytoplankton species, coupled with the occurrence of potentially toxic species and bloom densities of H. rotundata suggest that important changes have occurred in the phytoplankton assemblage that likely have affected the food web of these eutrophic bays.
Journal of Coastal Research, 2015
Steichen, J.L.; Denby, A.; Windham, R.; Brinkmeyer, R., and Quigg, A., 0000. A tale of two ports: Dinoflagellate and diatom communities found in the high ship traffic region of Galveston Bay, Texas (USA). Journal of Coastal Research, 00(0), 000-000. Coconut Creek (Florida), ISSN 0749-0208.
Journal of Plankton Research, 2004
A 2 year study of the phytoplankton community was carried out in the Indian River Lagoon, USA. In terms of biovolume, the phytoplankton community was generally dominated by dinoflagellates, diatoms or cyanobacteria. Mean phytoplankton standing crops were highest in the most flow-restricted regions of the lagoon, which had the lowest mean salinity values and comparatively high total nitrogen:total phosphorus ratios. In this region, blooms of dinoflagellates were common in the first year of the study, which was characterized by an El Niño event that yielded exceptionally high rainfall levels and freshwater outflow. Picoplanktonic cyanobacteria blooms became more prominent in the second year of the study, which was characterized by below average rainfall conditions. In unrestricted flow regions of the lagoon, located near inlets to the Atlantic Ocean, diatoms were most often the dominant taxa. Regions of intermediate water turnover rates and high external loading of phosphorus had a prevalence of diatom blooms. However, the average phytoplankton standing crops in the latter regions did not reach the levels experienced in the flow-restricted parts of the lagoon. In terms of individual phytoplankton taxa, the most common bloom-forming diatoms in the Indian River Lagoon system included: Skeletonema costatum, Dactyliosolen fragilissimus, Skeletonema menzelii, Cerataulina pelagica, Odontella regia, Chaetoceros lorenzianus, Rhizosolenia setigera and Thalassionema nitzschioides. The major bloom-forming dinoflagellate species included: Pheopolykrikos hartmannii, Akashiwo sanguinea, Prorocentrum micans, the potentially toxic species Pyrodinium bahamense var. bahamense and Prorocentrum minimum. Several picoplanktonic cyanobacteria were also prominent members of the phytoplankton community, including Synechococcus elongates. The spatial and temporal patterns observed in some of these dominant species were attributable to patterns in key environmental variables, including salinity, temperature and nutrient concentrations.
Journal of Aquaculture & Marine Biology, 2019
Small, shallow estuaries can be highly vulnerable to land use changes, eutrophication and habitat loss but are understudied with respect to their larger counterparts. Where they are monitored, the descriptors of their environmental status are typically chlorophyll a as a proxy for phytoplankton abundance and nutrient concentration as a presumed driver of the phytoplankton community. We present data from a shallow estuary, Weeks Bay, Alabama (USA), that demonstrates that chlorophyll a and nutrient concentrations are inadequate descriptors of ecological state. Weeks Bay had relatively high nutrient concentrations (86– 169µM total nitrogen and 1.0–5.2µM total phosphorus) and highly variable chlorophyll a concentrations (2.2–160.5μgL-1). The variability in chlorophyll a was most highly correlated with nutrient levels and river discharge. There was no relationship between chlorophyll a and community composition. Two of three maxima in chlorophyll a (>100μgL-1) were caused by non-toxic chlorophytes and diatoms; the third was dominated by potentially toxic raphidophyte Heterosigma akashiwo. The phytoplankton were diverse even at the class level and community composition varied on both annual and inter-annual scales. The best overall descriptor of phytoplankton composition was the annual cycle in temperature, but inter-annual variability was correlated with hydrology. In the winter, dominance by dinoflagellates, including several taxa that form harmful algal blooms, was correlated with low river discharge, low turbidity and high zooplankton numbers, while dominance by diatoms was correlated with high and variable river discharge and high turbidity. In the summer, dominance by cryptophytes versus diatoms was consistent with changes in groundwater discharge. The dominance of harmful algal bloom taxa vs non-toxic ones could not be inferred from chlorophyll a and/or nutrient concentrations.
2013
Phytoplankton samples were collected off the Monterey Municipal Wharf II at a single location (36º 36' N and 121º 53' W) weekly from June 2003 to March 2010. The contribution of five algal groups to total chlorophyll a (chl a) was derived using CHEMTAX from biomarker pigment measurements made via HPLC analysis. The purpose of this study was to specifically define the relative abundances of diatoms and dinoflagellates on a seasonal and interannual basis. Spearman's rho (ρ) correlation coefficients were calculated to determine the strength of the relationship between the diatoms and dinoflagellates and two environmental variables; sea surface temperature (SST) and upwelling indices (UI). During the summer of 2004 and until the end of 2006, previous studies had suggested that the typical diatom-dominated bay shifted to a dinoflagellate-dominated system resulting from global warming effects on mixed layer stability. The high-resolution (weekly), long-term (2003-2010) sampling regime described in the current study coincided with this time frame and allowed a robust test of the tenet that "the age of dinoflagellates" had developed in Monterey Bay. Pigment analysis indicated that diatoms and dinoflagellates displayed interannual and seasonal variability, particularly during the anomalous oceanographic conditions from 2004-2006. Diatoms were most abundant during the upwelling season and displayed a significant and positive correlation to UI, while they exhibited no relationship with shifts in SST. The dinoflagellates revealed a consistent fall bloom each year, displayed a significantly positive correlation to increases in SST and a significantly negative correlation to UI. This data set proved to be a robust, unique collection that clearly captured the "age of dinoflagellates" and compared well with larger scale studies conducted off shore waters of Monterey Bay, indicating the value of high frequency shore station based monitoring for tracking major oceanographic features. In this study, however, it was shown that the dominant period of dinoflagellates was short-lived since diatoms returned to dominance in 2007. vi
Estuarine, Coastal and Shelf Science, 2004
Water quality and phytoplankton were examined within the North Fork of the St. Lucie River Estuary, Florida (USA) from March 2000 to March 2001. Alterations in water-quality parameters and phytoplankton assemblages mirrored salinity regimes resulting from the 'wet'/'dry' seasonality of south Florida. Salinity was greatest during the 'dry', winter months whereas water temperature and nitrogen and phosphorus concentrations were greatest during the 'wet', summer months. A seasonal dissimilarity in phytoplankton occurred; cell abundance of cyanobacterial picoplankton (Synechocystis sp., Synechococcus sp.) and a diatom (Skeletonema costatum (Greville) Cleve) and cell carbon of a dinoflagellate (Gyrodinium sp.) and S. costatum were greatest during summer whereas abundance of chrysophytes (Chrysochromulina parva Lackey, Chromulina sp.) and carbon of dinoflagellates (Gymnodinium spp., Heterocapsa rotundata (Lohmann) Hansen) and a diatom (Cyclotella sp.) were greatest during winter. Watercolumn chlorophyll a concentrations reached up to 29 mg L ÿ1 and were negatively associated with salinity. Diatom chlorophyll comprised the majority and at times, greater than 90% of the total chlorophyll a. Picoplanktonic cyanobacteria comprised up to 5% and 1.4% of total phytoplankton carbon and chlorophyll a, respectively throughout the estuary; as such, its impact on overall assemblage rate processes and system-level function appeared minimal. Sediment and whole-water incubations confirmed the presence of heterotrophic dinoflagellates within the estuary. Dissolved oxygen concentrations did not correspond with total chlorophyll a concentrations and salinity, indicating that hypoxia within bottom waters during summer was not solely attributable to phytoplankton biomass or water-column stratification but likely, a result of multiple, interacting physical/chemical and biological factors.
Deep Sea Research Part II: Topical Studies in Oceanography, 2001
Qualitative and quantitative analyses of microphytoplankton communities were determined from samples collected in the northeast Atlantic Ocean in the early summer of 1996 during the PRIME Cruise of the RRS Discovery. A combination of light microscopy and scanning electron microscopy techniques was used to determine the species composition of two of the main groups of phytoplankton: Bacillariophyceae and Dinophyta. Two series of samples were collected; the "rst set of samples was collected between 18 and 29 June 1996 during a Lagrangian time-series study in the vicinity of 593N 203W tracking a mesoscale cold-core eddy; the second set of samples was collected between 4 and 10 July 1996 during a transect along the 203W meridian from 59 to 373N. A total of 155 samples were analysed over various depths down to 150 m, and 78 phytoplankton species were identi"ed. Samples taken during the Lagrangian time-series study were dominated by diatom species, including Ephemera planamembranacea and Pseudo-nitzschia species, whilst the main representative of the microphytoplankton dino#agellates was Ceratium fusus. On the transect, several Ceratium species were common, including C. furca C. fusus, and C. lineatum, and three other autotrophic dino#agellates were frequent including Prorocentrum minimum, Oxytoxum scolopax and Gonyaulax polygramma. A number of diatoms dominated the pro"les along the transect including Leptocylindrus mediterraneus, Thalassiosira oestrupii, and representatives of the genera Haslea and Pseudonitzschia. Standing stocks of both groups were low and typical of post-bloom carbon levels. Diatom biomass exceeded that of dino#agellate biomass in the eddy although the reverse situation was seen in the more southerly stations along the transect. Maximum abundances of the dino#agellate communities were situated in the surface waters within the mixed layer, while depth maxima of certain diatoms were noted at around 40 m below the depth of the mixed layer both in the Langrangian time-series study and along the transect. Microstrati"cation and nutrient stress may have contributed to losses of diatoms within the mixed layer due to sedimentation. Hierarchical classi"cation and ordination techniques were used to identify patterns in species assemblages. Four possible clusters of phytoplankton were identi"ed, each associated with a particular suite of environmental variables.
Phytoplankton samples were collected in Acapulco Bay during 2011 (January-April and Septem-ber) and 2012 (April-July, October, and November) with the objective of determining the abundance and species composition. Samples were collected in two stations located in the bay. A total of 82 species were identified: 42 dinoflagellates, 35 diatoms, three cyanobacteria, and two silicof-lagellates. Dinoflagellates were more abundant in the dry season, while diatoms dominated during rainy season. At least seven dinoflagellate species were recorded as potentially toxic, which may increase their populations and turn into harmful algal blooms (HABs) if environmental conditions within the bay are modified. In April 2012 a HAB of the non-toxic species Neoceratium balechii was documented.
Harmful Algae, 2004
The occurrence of potentially toxic phytoplankton species was examined over a 5-year period in a region of the Indian River Lagoon in Florida that has recently been subject to ecologically significant events, putatively related to algal toxins. The results of the study reveal a significant presence of two species of phytoplankton that have been shown to be toxic in Florida or other regions of world, the dinoflagellate Pyrodinium bahamense var. bahamense and the diatom Pseudo-nitzschia pseudodelicatissima. Concentrations of the former species reached 638,000 cells l −1 and concentrations of the latter reached 23.9 million cells l −1 . In addition, the abundance of one of these species, P. bahamense var. bahamense appears to have increased over the 5-year study period from 1997 to 2002. It may be hypothesized that rainfall events following a regional drought period resulted in a flushing of bioavailable phosphorus and nitrogen into the Indian River Lagoon that stimulated P. bahamense var. bahamense blooms. The significance of these results is discussed within the context of the ecology of this flow-restricted lagoon.