Seasonal patterns of phytoplankton biomass and composition in the inner continental shelf off Cap... more Seasonal patterns of phytoplankton biomass and composition in the inner continental shelf off Cape Canaveral on the east coast of Florida were examined for a 6-year period (2013–2019). In situ water samples were collected and analyzed for chlorophyll a, phytoplankton biomass and composition, along with water quality parameters. Regional satellite data on chlorophyll a, and temperature was also obtained from NASA. Average chlorophyll a values over the study period ranged from 0.63 ± 0.03 μg L−1 in the summer to 2.55 ± 0.10 μg L−1 in the fall. Phytoplankton community composition also showed seasonal differences, with persistent dominance by picoplanktonic cyanobacteria in the summer, but mixed dominance by picocyanobacteria and dinoflagellates in the fall. Seasonal differences were attributed to a shift in predominant seasonal wind directions, which drive water along the coast from the north in the fall and winter, but from the south in the spring and summer, including eddies and upwe...
Within the Indian River Lagoon (IRL), blooms of the marine microalga Aureoumbra lagunensis in exc... more Within the Indian River Lagoon (IRL), blooms of the marine microalga Aureoumbra lagunensis in excess of 1310 cells ml 1 have occurred on three occasions after first being locally identified in 2012. All blooms coincided with times of peak reproduction and growth of the eastern oyster Crassostrea virginica in Mosquito Lagoon (northern IRL). Over six years of field data on monthly recruitment of C. virginica were compared to bi-monthly cell counts of A. lagunensis. In addition to expected temperature and salinity-driven variations in oyster recruitment, cell counts of A. lagunensis in excess of 10,000 ml 1 reduced oyster recruitment. A second method of analysis similarly found a negative association with oyster recruitment when cell counts exceeded 9658 ml . Understanding the impact of blooms of A. lagunensis is essential for managing harvesting, aquaculture, and restoration of this foundation shellfish species.
The abundance and composition of the phytoplankton community off the coast of Cape Canaveral, Flo... more The abundance and composition of the phytoplankton community off the coast of Cape Canaveral, Florida was examined from Fall 2013 to Summer 2015. The region is a shallow shelf environment. Water samples were collected quarterly at 24 sites from the surface and bottom of the water column; temperature and nutrient concentrations were determined. Photoautotrophic picoplanktonic prokaryotes were consistently important in terms of numerical abundance and biomass throughout the study. Among the cyanobacteria, a surface bloom of the nitrogen-fixing filamentous species Trichodesmium was observed in Fall 2013. Dinoflagellates and diatoms were also major contributors to phytoplankton biomass. Many of the dominant dinoflagellates were mixotrophic or heterotrophic species. Nanoplanktonic eukaryotic algae were also periodically an important group in terms of biomass, such as prasinophytes (Chlorophyta). No consistent and reoccurring spatial patterns were observed, likely due to the dynamic water...
Abstract In 2018, the presence of bottom water hypoxia along the SW Florida coast was investigate... more Abstract In 2018, the presence of bottom water hypoxia along the SW Florida coast was investigated during a bloom of the toxic dinoflagellate Karenia brevis. The bloom was first detected in November 2017. Monitoring of oxygen levels and bloom densities were carried out in 2018 and 2019 using sampling grids. Vertical profiles indicated a pycnocline at 3–4 m where warmer, lower salinity water was at the surface, while the deeper hypoxic layer was colder with higher salinity. There were significantly higher abundances of K. brevis in the surface water compared to the hypoxic bottom water in September 2018. At two fixed sites dissolved oxygen was measured continuously showing hypoxic conditions during that month. Geospatial analysis of vertical profile data yielded an estimate that the hypoxic layer covered an area of at least 655 km2. The possible influences of red tides on hypoxic conditions along the coast of the eastern Gulf of Mexico and are discussed within the context of the 2018 K. brevis bloom event. Hypoxia occurring in parallel to a red tide bloom is more likely to occur with warmer ocean temperatures and increased fluxes of nutrients and fresh water to the Gulf of Mexico after hurricanes.
The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosy... more The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosystem that is negatively affected by recurring harmful algal blooms (HABs) from distinct taxonomic/functional groups. Enhanced monitoring was established to facilitate rapid quantification of three recurrent bloom taxa, Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia spp., and included corroborating techniques to improve the identification of small-celled nanoplankton (<10 μm in diameter). Identification and enumeration of these target taxa were conducted during 2015–2020 using a combination of light microscopy and species-specific approaches, specifically immunofluorescence flow cytometry as well as a newly developed qPCR assay for A. lagunensis presented here for the first time. An annual bloom index (ABI) was established for each taxon based on occurrence and abundance data. Blooms of A. lagunensis (>2 × 108 cells L–1) were observed in all 6 years sampled and ac...
This paper examines the character of phytoplankton blooms in a restricted sub-tropical lagoon alo... more This paper examines the character of phytoplankton blooms in a restricted sub-tropical lagoon along the Atlantic coast of central Florida. The results of the 23-year study (1997–2020) provide evidence for multiple types of variability in bloom activity, including cyclical patterns, stochastic events, and most prominently a regime shift in composition and intensity. Cyclical patterns (e.g., El Niño/La Niña periods) and stochastic events (e.g., tropical storms) influenced rainfall levels, which in turn impacted nutrient concentrations in the water column and the timing and intensity of blooms. In 2011, a major change occurred in the character of blooms, with a dramatic increase in peak biomass levels of blooms and the appearance of new dominant taxa, including the brown tide species Aureoumbra lagunensis and other nanoplanktonic species. Results of quantitative analyses reveal system behavior indicative of a regime shift. The shift coincided with widespread losses of seagrass communit...
A microscopic study of microplankton in two coastal lagoons in the Florida Keys coincidently, and... more A microscopic study of microplankton in two coastal lagoons in the Florida Keys coincidently, and unexpectedly, revealed the widespread presence of high concentrations of polystyrene microplastic particles. The polystyrene particles were first observed in the second year of a 2-year study of phytoplankton communities, with peak densities in the spring/summer of 2019 at all ten sampling sites in the two lagoons. Polystyrene particle densities reached levels up to 76,000 L−1. The particles ranged in size from 33 to 190 µm, similar to the size range of microplanktonic algae (20–200 µm). Over the period of peak polystyrene densities, average particle densities were similar to average densities of microplanktonic algae cells. The latter observation highlights the potential significance of the microplastic particles for the ecology of the pristine waters of the Florida Keys, if they persist.
Concerns about global climate change have heightened awareness of the role changing rainfall regi... more Concerns about global climate change have heightened awareness of the role changing rainfall regimes play in altering plankton communities of coastal ecosystems. In this study spatial and temporal patterns of phytoplankton composition and biomass in a sub-tropical tidal creek in Florida were observed over three wet and dry seasons, which included the major storm year of 2005 and the drought year of 2006. Shifts in rainfall levels were associated with changes in phytoplankton composition and biomass, but the effects varied between the upper and lower reaches of the creek. The upper reach of the creek was fresh throughout the study period. The oligohaline to mesohaline lower creek alternated between fresh and marine species in response to shifts in salinity regimes. Blooms of the freshwater dinoflagellate Peridinium sp., small centric diatoms and nitrogen-fixing cyanobacteria were common in the upper Ten Mile Creek during low rainfall years. The euryhaline marine dinoflagellate Akashi...
We analyzed spatial and temporal patterns and relationships in water quality in order to investig... more We analyzed spatial and temporal patterns and relationships in water quality in order to investigate causes and short-term consequences of a historically unprecedented phytoplankton bloom that afflicted the Indian River Lagoon (IRL) system during 2011. The 2011 ‘superbloom’ was unprecedented, not only for its magnitude (chlorophyll_a concentrations > 130 ug/L) and geographic scale (Banana, north Indian River and southern Mosquito sub-lagoons), but also for its long (7+ month) duration and its distinctive floral composition (co-dominated by green micro-flagellates and pico-cyanobacteria). We used a combination of statistical approaches to compare water quality during 2011 to that of antecedent periods, and to explore relationships between chlorophyll_a and other water quality constituents before and during the bloom. Bottom-up effects (nutrients) and other physical-chemical factors (e.g., salinity and water temperature) are explored as ‘drivers’ or ‘triggers’ of the bloom. The con...
Seasonal patterns of phytoplankton biomass and composition in the inner continental shelf off Cap... more Seasonal patterns of phytoplankton biomass and composition in the inner continental shelf off Cape Canaveral on the east coast of Florida were examined for a 6-year period (2013–2019). In situ water samples were collected and analyzed for chlorophyll a, phytoplankton biomass and composition, along with water quality parameters. Regional satellite data on chlorophyll a, and temperature was also obtained from NASA. Average chlorophyll a values over the study period ranged from 0.63 ± 0.03 μg L−1 in the summer to 2.55 ± 0.10 μg L−1 in the fall. Phytoplankton community composition also showed seasonal differences, with persistent dominance by picoplanktonic cyanobacteria in the summer, but mixed dominance by picocyanobacteria and dinoflagellates in the fall. Seasonal differences were attributed to a shift in predominant seasonal wind directions, which drive water along the coast from the north in the fall and winter, but from the south in the spring and summer, including eddies and upwe...
Within the Indian River Lagoon (IRL), blooms of the marine microalga Aureoumbra lagunensis in exc... more Within the Indian River Lagoon (IRL), blooms of the marine microalga Aureoumbra lagunensis in excess of 1310 cells ml 1 have occurred on three occasions after first being locally identified in 2012. All blooms coincided with times of peak reproduction and growth of the eastern oyster Crassostrea virginica in Mosquito Lagoon (northern IRL). Over six years of field data on monthly recruitment of C. virginica were compared to bi-monthly cell counts of A. lagunensis. In addition to expected temperature and salinity-driven variations in oyster recruitment, cell counts of A. lagunensis in excess of 10,000 ml 1 reduced oyster recruitment. A second method of analysis similarly found a negative association with oyster recruitment when cell counts exceeded 9658 ml . Understanding the impact of blooms of A. lagunensis is essential for managing harvesting, aquaculture, and restoration of this foundation shellfish species.
The abundance and composition of the phytoplankton community off the coast of Cape Canaveral, Flo... more The abundance and composition of the phytoplankton community off the coast of Cape Canaveral, Florida was examined from Fall 2013 to Summer 2015. The region is a shallow shelf environment. Water samples were collected quarterly at 24 sites from the surface and bottom of the water column; temperature and nutrient concentrations were determined. Photoautotrophic picoplanktonic prokaryotes were consistently important in terms of numerical abundance and biomass throughout the study. Among the cyanobacteria, a surface bloom of the nitrogen-fixing filamentous species Trichodesmium was observed in Fall 2013. Dinoflagellates and diatoms were also major contributors to phytoplankton biomass. Many of the dominant dinoflagellates were mixotrophic or heterotrophic species. Nanoplanktonic eukaryotic algae were also periodically an important group in terms of biomass, such as prasinophytes (Chlorophyta). No consistent and reoccurring spatial patterns were observed, likely due to the dynamic water...
Abstract In 2018, the presence of bottom water hypoxia along the SW Florida coast was investigate... more Abstract In 2018, the presence of bottom water hypoxia along the SW Florida coast was investigated during a bloom of the toxic dinoflagellate Karenia brevis. The bloom was first detected in November 2017. Monitoring of oxygen levels and bloom densities were carried out in 2018 and 2019 using sampling grids. Vertical profiles indicated a pycnocline at 3–4 m where warmer, lower salinity water was at the surface, while the deeper hypoxic layer was colder with higher salinity. There were significantly higher abundances of K. brevis in the surface water compared to the hypoxic bottom water in September 2018. At two fixed sites dissolved oxygen was measured continuously showing hypoxic conditions during that month. Geospatial analysis of vertical profile data yielded an estimate that the hypoxic layer covered an area of at least 655 km2. The possible influences of red tides on hypoxic conditions along the coast of the eastern Gulf of Mexico and are discussed within the context of the 2018 K. brevis bloom event. Hypoxia occurring in parallel to a red tide bloom is more likely to occur with warmer ocean temperatures and increased fluxes of nutrients and fresh water to the Gulf of Mexico after hurricanes.
The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosy... more The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosystem that is negatively affected by recurring harmful algal blooms (HABs) from distinct taxonomic/functional groups. Enhanced monitoring was established to facilitate rapid quantification of three recurrent bloom taxa, Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia spp., and included corroborating techniques to improve the identification of small-celled nanoplankton (<10 μm in diameter). Identification and enumeration of these target taxa were conducted during 2015–2020 using a combination of light microscopy and species-specific approaches, specifically immunofluorescence flow cytometry as well as a newly developed qPCR assay for A. lagunensis presented here for the first time. An annual bloom index (ABI) was established for each taxon based on occurrence and abundance data. Blooms of A. lagunensis (>2 × 108 cells L–1) were observed in all 6 years sampled and ac...
This paper examines the character of phytoplankton blooms in a restricted sub-tropical lagoon alo... more This paper examines the character of phytoplankton blooms in a restricted sub-tropical lagoon along the Atlantic coast of central Florida. The results of the 23-year study (1997–2020) provide evidence for multiple types of variability in bloom activity, including cyclical patterns, stochastic events, and most prominently a regime shift in composition and intensity. Cyclical patterns (e.g., El Niño/La Niña periods) and stochastic events (e.g., tropical storms) influenced rainfall levels, which in turn impacted nutrient concentrations in the water column and the timing and intensity of blooms. In 2011, a major change occurred in the character of blooms, with a dramatic increase in peak biomass levels of blooms and the appearance of new dominant taxa, including the brown tide species Aureoumbra lagunensis and other nanoplanktonic species. Results of quantitative analyses reveal system behavior indicative of a regime shift. The shift coincided with widespread losses of seagrass communit...
A microscopic study of microplankton in two coastal lagoons in the Florida Keys coincidently, and... more A microscopic study of microplankton in two coastal lagoons in the Florida Keys coincidently, and unexpectedly, revealed the widespread presence of high concentrations of polystyrene microplastic particles. The polystyrene particles were first observed in the second year of a 2-year study of phytoplankton communities, with peak densities in the spring/summer of 2019 at all ten sampling sites in the two lagoons. Polystyrene particle densities reached levels up to 76,000 L−1. The particles ranged in size from 33 to 190 µm, similar to the size range of microplanktonic algae (20–200 µm). Over the period of peak polystyrene densities, average particle densities were similar to average densities of microplanktonic algae cells. The latter observation highlights the potential significance of the microplastic particles for the ecology of the pristine waters of the Florida Keys, if they persist.
Concerns about global climate change have heightened awareness of the role changing rainfall regi... more Concerns about global climate change have heightened awareness of the role changing rainfall regimes play in altering plankton communities of coastal ecosystems. In this study spatial and temporal patterns of phytoplankton composition and biomass in a sub-tropical tidal creek in Florida were observed over three wet and dry seasons, which included the major storm year of 2005 and the drought year of 2006. Shifts in rainfall levels were associated with changes in phytoplankton composition and biomass, but the effects varied between the upper and lower reaches of the creek. The upper reach of the creek was fresh throughout the study period. The oligohaline to mesohaline lower creek alternated between fresh and marine species in response to shifts in salinity regimes. Blooms of the freshwater dinoflagellate Peridinium sp., small centric diatoms and nitrogen-fixing cyanobacteria were common in the upper Ten Mile Creek during low rainfall years. The euryhaline marine dinoflagellate Akashi...
We analyzed spatial and temporal patterns and relationships in water quality in order to investig... more We analyzed spatial and temporal patterns and relationships in water quality in order to investigate causes and short-term consequences of a historically unprecedented phytoplankton bloom that afflicted the Indian River Lagoon (IRL) system during 2011. The 2011 ‘superbloom’ was unprecedented, not only for its magnitude (chlorophyll_a concentrations > 130 ug/L) and geographic scale (Banana, north Indian River and southern Mosquito sub-lagoons), but also for its long (7+ month) duration and its distinctive floral composition (co-dominated by green micro-flagellates and pico-cyanobacteria). We used a combination of statistical approaches to compare water quality during 2011 to that of antecedent periods, and to explore relationships between chlorophyll_a and other water quality constituents before and during the bloom. Bottom-up effects (nutrients) and other physical-chemical factors (e.g., salinity and water temperature) are explored as ‘drivers’ or ‘triggers’ of the bloom. The con...
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