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Full-Text Articles in Life Sciences

Phytoplankton Thermal Trait Parameterization Alters Community Structure And Biogeochemical Processes In A Modeled Ocean, Stephanie I. Anderson, Clara Fronda, Andrew D. Barton, Sophie Clayton, Tatiana A. Rynearson, Stephanie Dutkiewicz Jan 2023

Phytoplankton Thermal Trait Parameterization Alters Community Structure And Biogeochemical Processes In A Modeled Ocean, Stephanie I. Anderson, Clara Fronda, Andrew D. Barton, Sophie Clayton, Tatiana A. Rynearson, Stephanie Dutkiewicz

OES Faculty Publications

Phytoplankton exhibit diverse physiological responses to temperature which influence their fitness in the environment and consequently alter their community structure. Here, we explored the sensitivity of phytoplankton community structure to thermal response parameterization in a modelled marine phytoplankton community. Using published empirical data, we evaluated the maximum thermal growth rates (μmax) and temperature coefficients (Q10; the rate at which growth scales with temperature) of six key Phytoplankton Functional Types (PFTs): coccolithophores, cyanobacteria, diatoms, diazotrophs, dinoflagellates, and green algae. Following three well-documented methods, PFTs were either assumed to have (1) the same μmax and …


Alexandrium In The Arctic: Are Harmful Algae Spreading As The Arctic Warms?, Sveinn Einarsson, Kate Lowry, Robert Pickart, Karin Ashjian, P. Dreux Chappell Apr 2021

Alexandrium In The Arctic: Are Harmful Algae Spreading As The Arctic Warms?, Sveinn Einarsson, Kate Lowry, Robert Pickart, Karin Ashjian, P. Dreux Chappell

College of Sciences Posters

Alexandrium tamerense is a well-studied dinoflagellate known for its ability to produce the neurotoxin that causes paralytic shellfish poisoning. Until 1970 Alexandrium tamerense was only found in Europe, North America, and Japan but has been increasingly found all over the globe. Alexandrium is characteristically found in temperate and subtropical regions and as the Arctic warms, there is considerable concern that it may be expanding into the Arctic. We found Alexandrium tamerense during a research expedition to the Alaskan Beaufort Sea shelf to study upwelling. Upwelling events are known to support seasonal blooms of phytoplankton, which are important primary producers at …


Fast And Pervasive Transcriptomic Resilience And Acclimation Of Extremely Heat-Tolerant Coral Holobionts From The Northern Red Sea, Romain Savary, Daniel J. Barshis, Christian R. Voolstra, Anny Cárdenas, Nicolas R. Evensen, Guilhem Banc-Prandi, Maoz Fine, Anders Meiborn Jan 2021

Fast And Pervasive Transcriptomic Resilience And Acclimation Of Extremely Heat-Tolerant Coral Holobionts From The Northern Red Sea, Romain Savary, Daniel J. Barshis, Christian R. Voolstra, Anny Cárdenas, Nicolas R. Evensen, Guilhem Banc-Prandi, Maoz Fine, Anders Meiborn

Biological Sciences Faculty Publications

Corals from the northern Red Sea and Gulf of Aqaba exhibit extreme thermal tolerance. To examine the underlying gene expression dynamics, we exposed Stylophora pistillata from the Gulf of Aqaba to short-term (hours) and long-term (weeks) heat stress with peak seawater temperatures ranging from their maximum monthly mean of 27 °C (baseline) to 29.5 °C, 32 °C, and 34.5 °C. Corals were sampled at the end of the heat stress as well as after a recovery period at baseline temperature. Changes in coral host and symbiotic algal gene expression were determined via RNA-sequencing (RNA-Seq). Shifts in coral microbiome composition were …


Cyanobacteria Dominance In The Oligohaline Waters Of Back Bay, Virginia, Harold G. Marshall Jan 2012

Cyanobacteria Dominance In The Oligohaline Waters Of Back Bay, Virginia, Harold G. Marshall

Biological Sciences Faculty Publications

Back Bay and its flora have historically been influenced by the interaction of freshwater flow in combination with frequent intrusion of saline water into its basin. These events have resulted in a dynamic environmental setting influencing the abundance and composition of its phytoplankton community. Dominating these oligohaline waters is a diverse representation and high abundance of freshwater filamentous and colonial cyanobacteria. These include the nonheterocystous Planktolyngbya contorta, Planktolyngbya limnetica, and Pseudanabaena limnetica, taxa implicated as bloom producers in Bay waters with N:P molar ratios ranging from 23:1 to 74:1.


Characterization Of Heterogeneities And Domains In Aquatic And Sedimentary Organic Matter By 1 H Spin Diffusion: Potential For Elucidating The Formation Mechanisms, Jingdong Mao, Xiaoyan Cao Jan 2011

Characterization Of Heterogeneities And Domains In Aquatic And Sedimentary Organic Matter By 1 H Spin Diffusion: Potential For Elucidating The Formation Mechanisms, Jingdong Mao, Xiaoyan Cao

Chemistry & Biochemistry Faculty Publications

Although the information on domains and heterogeneities of natural organic matter (NOM) can provide insights into its formation mechanisms, the appropriate solid-state NMR technique for measuring them is still lacking. The traditional technique requires mobility differences in NOM whereas NOM components are primarily rigid. We introduced a new 1H spin diffusion technique, 1H-13C two-dimensional heteronuclear correlation (2D HETCOR) NMR with 1H spin diffusion, for characterization of domains and heterogeneities in aquatic and sedimentary organic matter. It was achieved by collecting a series of 2D HETCOR spectra with a variable mixing time, tm', and …


Phosphorus Uptake In Rhodomonas Salina (Wislouch) And Its Effect On Allocation And Elimination In Acartia Tonsa (Dana), Danna Palladino Oct 2010

Phosphorus Uptake In Rhodomonas Salina (Wislouch) And Its Effect On Allocation And Elimination In Acartia Tonsa (Dana), Danna Palladino

OES Theses and Dissertations

Phosphorus is a key element in important biochemical compounds, such as RNA and phospholipids, and can become limiting in a variety of marine systems. The uptake of phosphorus into biochemical fractions (protein, low molecular weight (LMW) compounds, lipid, polysaccharide and nucleic acid) in Acartia tonsa fed 33P -labeled Rhodomonas salina was examined. R. salina was cultured on two variations of one media that in one case contained phosphorus in balance and the other out of balance with relation to other standard f/2 components. The P-balanced (PB) media had a N:P ratio of 24.5, which is higher than that found …


Light Dependence Of Selenium Uptake By Phytoplankton And Implications For Predicting Selenium Incorporation Into Food Webs, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter, Lynda S. Cutter, Brian Cole Jan 2004

Light Dependence Of Selenium Uptake By Phytoplankton And Implications For Predicting Selenium Incorporation Into Food Webs, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter, Lynda S. Cutter, Brian Cole

OES Faculty Publications

The potentially toxic element selenium is first concentrated from solution to a large but highly variable degree by algae and bacteria before being passed on to consumers. The large loads of abiotic and detrital suspended particles often present in rivers and estuaries may obscure spatial and temporal patterns in Se concentrations at the base of the food web. We used radiotracers to estimate uptake of both selenite (Se(IV)) and C by intact plankton communities at two sites in the Sacramento/San Joaquin River Delta. Our goals were to determine (1) whether C and Se(IV) uptake were coupled, (2) the role of …


Monitoring Results For Pfiesteria Piscidida And Pfiesteria-Like Organisms From Virginia Waters In 1998, Harold G. Marshall, David W. Seaborn, Jennifer Wolny Jan 1999

Monitoring Results For Pfiesteria Piscidida And Pfiesteria-Like Organisms From Virginia Waters In 1998, Harold G. Marshall, David W. Seaborn, Jennifer Wolny

Virginia Journal of Science

Results of an extensive 1998 monitoring program for the presence of Pfiesteria-like organisms (PLO) in Virginia estuaries indicate these dinoflagellates are widely distributed in both the water column, and as cysts in the sediment, however Pfiesteria piscicida was not detected at this time. The highest concentrations of PLO were in estuaries along the Virginia shore line of the Potomac River, and in western Chesapeake Bay estuaries from the Little Wicomico River to the Rappahannock River. The most common PLO included Cryptoperidiniopsis sp. and Gymnodinium galatheanum. The lowest PLO concentrations were at ocean side locations. PLO were also …


Pfiesteria Piscicida And Dinoflagellates Similar To Pfiesteria, Harold G. Marshall Jan 1999

Pfiesteria Piscicida And Dinoflagellates Similar To Pfiesteria, Harold G. Marshall

Biological Sciences Faculty Publications

Pfiesteria pisiccida is a microscopic, unicellular organism that is classified as both a mixotrophic and heterotrophic dinoflagellate, which has been associated with both fish deaths and a cause of human illness (Burkholder et al., 1992; Glasglow et al., 1995; Burkholder and Glasgow, 1997). This species possesses a complex life cycle that includes motile forms (e.g. zoospores, gametes, amoebae) and a cyst stage that may remain dormant in the sediment (Burkholder et al, 1995b). Pfiesteria piscicida is known to have toxin and non-toxin producing populations, where cyst transformation into the toxic motile zoospores may be initiated by the presence of certain …


Comparative Study Of Selenium Requirements Of Three Phytoplankton Species: Gymnodinium Catenatum, Alexandrium Minutum (Dinophyta) And Chaetoceros Cf. Tenuissimus (Bacillariophyta, Martina A. Doblin, Susan I. Blackburn, Gustaaf M. Hallegraeff Jan 1999

Comparative Study Of Selenium Requirements Of Three Phytoplankton Species: Gymnodinium Catenatum, Alexandrium Minutum (Dinophyta) And Chaetoceros Cf. Tenuissimus (Bacillariophyta, Martina A. Doblin, Susan I. Blackburn, Gustaaf M. Hallegraeff

OES Faculty Publications

This study investigated the selenium (Se) requirements of three phytoplankton species which commonly bloom in southern Australian estuaries. The present study showed that the toxic dinoflagellate Gymnodinium catenatum Graham had an obligate requirement for Se (IV) in culture. After two transfers (~ 4 weeks ≈ 7 generations) in Se-deficient seawater medium, this phytoplankton species exhibited a decline in growth rate (25%) and biomass yield (90%), while complete cessation of cell division occurred under prolonged (8 weeks ≈ 12 generations) Se starvation. Addition of 10-9-10-7 M H2SeO3 to nutrient-enriched seawater medium resulted in increased G.catenatum …


Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998., Everett P. Weber, Harold G. Marshall Jan 1999

Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998., Everett P. Weber, Harold G. Marshall

Biological Sciences Faculty Publications

A series of statistical analyses were performed to identify the relationship between abundance of dinoflagellates grouped as Pfiesteria-like organisms and a set of 25 water quality variables from May through October of 1998 at 41 estuarine locations. Although regions were identified in relation to seasonal density of cells present, there were no strong relationships to specific water quality variables. Factors that may have influenced these results included: a) several species were included in the group analyzed and this composite did not respond as a unit to changing environmental conditions; b) cell concentrations were low and there were a large …


Monitoring Results For Pfiesteria Piscidida And Pfiesteria-Like Organisms From Virginia Waters In 1998, Harold G. Marshall, David W. Seaborn, Jennifer Wolny Jan 1999

Monitoring Results For Pfiesteria Piscidida And Pfiesteria-Like Organisms From Virginia Waters In 1998, Harold G. Marshall, David W. Seaborn, Jennifer Wolny

Biological Sciences Faculty Publications

Results of an extensive 1998 monitoring program for the presence of Pfiesteria-like organisms (PLO) in Virginia estuaries indicate these dinoflagellates are widely distributed in both the water column, and as cysts in the sediment, however Pfiesteria piscicida was not detected at this time. The highest concentrations of PLO were in estuaries along the Virginia shore line of the Potomac River, and in western Chesapeake Bay estuaries from the Little Wicomico River to the Rappahannock River. The most common PLO included Cryptoperidiniopsis sp. and Gymnodinium galatheanum. The lowest PLO concentrations were at ocean side locations. PLO were also …


Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998, Everett P. Weber, Harold G. Marshall Jan 1999

Water Quality Relationships To Concentrations Of Pfiesteria-Like Organisms In Virginia Estuaries For 1998, Everett P. Weber, Harold G. Marshall

Virginia Journal of Science

A series of statistical analyses were performed to identify the relationship between abundance of dinoflagellates grouped as Pfiesteria-like organisms and a set of 25 water quality variables from May through October of 1998 at 41 estuarine locations. Although regions were identified in relation to seasonal density of cells present, there were no strong relationships to specific water quality variables. Factors that may have influenced these results included: a) several species were included in the group analyzed and this composite did not respond as a unit to changing environmental conditions; b) cell concentrations were low and there were a large …


Toxin Producing Phytoplankton In Chesapeake Bay, Harold G. Marshall Jan 1996

Toxin Producing Phytoplankton In Chesapeake Bay, Harold G. Marshall

Biological Sciences Faculty Publications

Three diatoms and nine dinoflagellates, known to be associated with toxin production, have been identified within Chesapeake Bay. Over the past several decades this number has increased to its present level so that they now represent approximately 1.7% the total number of phytoplankton species reported for the Bay.


Seasonal Phytoplankton Development Within Three Rivers In The Lower Chesapeake Bay Region, Harold G. Marshall, Lewis F. Affronti Jan 1992

Seasonal Phytoplankton Development Within Three Rivers In The Lower Chesapeake Bay Region, Harold G. Marshall, Lewis F. Affronti

Biological Sciences Faculty Publications

The seasonal and inter-annual concentrations of phytoplankton were studied over a 50 month period in the lower James, York and Rappahannock Rivers (USA). Differences in the onset, duration and magnitude of major seasonal growth periods varied from year to year. There was a tendency for spring, summer and fall maxima, with a winter period of reduced abundance. An additional study of picoplankton over a 12 month period indicated greatest abundance during summer and fall, with least development in winter.


Observations Of The Phytoplankton Standing Crop At The Shelf Margin Of The Mid Atlantic Bight, Bruce B. Wagoner, Harold G. Marshall Jan 1991

Observations Of The Phytoplankton Standing Crop At The Shelf Margin Of The Mid Atlantic Bight, Bruce B. Wagoner, Harold G. Marshall

Biological Sciences Faculty Publications

A comparison of the total percentage cell abundance and cell biovolume relationships of major phytoplankton categories was made between two station sets across the shelf margin. Diatom values for abundance and biovolume were greater at oceanic stations compared to the outer shelf stations, with dinoflagellates having the reverse pattern. The composite contributions to biovolume and abundance in the standing crop from other phytoplankton categories were greater over the outer shelf than beyond the shelf margin. The major source of biovolume (biomass) from the outer shelf and these oceanic stations came from the diatoms and dinoflagellates, with an average mean of …


The Effects Of Siltation On Recruitment Of Spiny Lobsters, Panulirus Argus, William F. Herrnkind, Mark J. Butler, Richard A. Tankersley Jan 1988

The Effects Of Siltation On Recruitment Of Spiny Lobsters, Panulirus Argus, William F. Herrnkind, Mark J. Butler, Richard A. Tankersley

Biological Sciences Faculty Publications

Fewer juvenile pinry lobsters were found in areas of the Florida Keys where their primary habitat was heavily silted as compared with similar, less silted habitat. Several hypotheses explaining this relationship were tested, and the time-to-metamorphosis was compared for settling pueruli within silted and nonsilted algae stands. Limited postlarval settlement and avoidance of silted algal habitats by juveniles, probably accounts for the paucity of young lobsters in heavily silted sites. In addition, although juvenile lobsters are nonselective predators, lower prey availability in silted algae probably promotes transciency which, in turn, causes increased mortality by predation while juveniles are exposed.


Phytoplankton Studies Within The Virginia Barrier Islands I. Seasonal Study Of Phytoplankton In Goose Lake, Parramore Island, Harold G. Marshall Jan 1980

Phytoplankton Studies Within The Virginia Barrier Islands I. Seasonal Study Of Phytoplankton In Goose Lake, Parramore Island, Harold G. Marshall

Biological Sciences Faculty Publications

The phytoplankton of Goose Lake, an oligohaline lake on Parramore Island, was studied for one year. The populations consisted primarily of ultraplankton and nanoplankton-sized forms with diatoms and chlorophyceans dominant most of the year. A general pattern of seasonally higher cell concentrations in early summer and fall was noted, with an unidentified ultraplankton-sized component prominent throughout the collection period. A list of 154 species is given.


Microbenthic Algal Production Of An Intertidal Sandflat In Little Creek Harbor, Virginia Beach, Virginia, Clayton Barry Shedrow Jul 1975

Microbenthic Algal Production Of An Intertidal Sandflat In Little Creek Harbor, Virginia Beach, Virginia, Clayton Barry Shedrow

OES Theses and Dissertations

Estimated annual net microbenthic algal production of an intertidal sandflat on Little Creek Inlet, Virginia Beach, Virginia, was 105 g C/m2. Seasonally, primary production was greatest during the summer and fall periods (38 and 49 g C/m2, respectively). Productivity was found to vary directly with water temperature and standing crop of benthic diatoms, and inversely with incident solar radiation and standing crops of sedimentary chlorophyll 'a' and 'c'. Orthophosphate and nitrate-N appeared to be limiting factors, nitrate-N more so than orthophosphate. Mean annual net photosynthetic efficiency (based upon total light) for the microphytobenthic community was 0.09%. …


Diurnal Distribution Of Phytoplankton From A Single Station At The Mouth Of The James River, Harold G. Marshall Jan 1966

Diurnal Distribution Of Phytoplankton From A Single Station At The Mouth Of The James River, Harold G. Marshall

Biological Sciences Faculty Publications

Eight sets of water samples were taken to a depth of 36 ft. during a 24-hr. period. A homogeneity was found in the vertical distribution of the total phytoplankton in samples from 7 of the 8 hydro-casts. Skeletonema costatum and Asterionella japonica were the most numerous phytoplankters in every sample, with the majority of their counts each exceeding 500, 000 cells per liter.


The Annual Distribution And Stratification Of Phytoplankton At Aurora Lake, Portage County, Ohio, Harold G. Marshall Jan 1965

The Annual Distribution And Stratification Of Phytoplankton At Aurora Lake, Portage County, Ohio, Harold G. Marshall

Biological Sciences Faculty Publications

A 13-month study of a hard-water lake in northeast Ohio has provided a quantitative and qualitative record of the seasonal changes of the phytoplankton. Maximum production occurred during the summer and winter periods. The summer pulse was dominated by the cyanophyte species: Microcystis aeruginosa, Anabaena spiroides, A. circinalis, and Aphanizomenon flosaquae. The dominants of the winter pulse were the diatoms Fragilaria crotomensis and Asterionella formosa, which formed separate peaks under an ice cover in December and January, respectively. The January development extended into March with the highest concentrations for the year Being reached at approximately …