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Phytoplankton

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Articles 1 - 30 of 187

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Modeling Upper Ocean Ecosystem Dynamics In Response To Interannual Sea-Ice Variability In The Western Antarctic Peninsula, Catherine R. Czajka, Jessica S. Turner, Sharon Stammerjohn, Heather H. Kim, Oscar Schofield, Benjamin T. Saenz, Scott C. Doney Jan 2026

Modeling Upper Ocean Ecosystem Dynamics In Response To Interannual Sea-Ice Variability In The Western Antarctic Peninsula, Catherine R. Czajka, Jessica S. Turner, Sharon Stammerjohn, Heather H. Kim, Oscar Schofield, Benjamin T. Saenz, Scott C. Doney

OES Faculty Publications

In the Western Antarctic Peninsula (WAP), marine plankton dynamics are tightly linked to the interannual variability in environmental conditions, including phenological shifts in sea-ice seasonality. To explore these linkages, we use a 1-dimensional vertical ocean-ice-ecosystem model (KPP-Eco-Ice, or KEI) that simulates physical and ecosystem conditions at a continental shelf mooring location in the Palmer Long Term Ecological Research program sampling grid. KEI allows for year-round examination of the ecosystem in a region where in situ observations on the shelf are limited to January. Comparisons are made between seasonal sea-ice retreat, mixed layer depth, primary productivity, and phytoplankton relative abundance, grazing, …

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Linking Phytoplankton Physiology And Ecology To Global Biogeochemical Cycles: A Modeling Approach, Margaret Bernish Jan 2026

Linking Phytoplankton Physiology And Ecology To Global Biogeochemical Cycles: A Modeling Approach, Margaret Bernish

Open Access Dissertations

Phytoplankton, or microscopic primary producers, contribute to carbon export through the biological transformation of carbon dioxide into organic molecules. Phytoplankton are responsible for approximately half of global net primary production, while only contributing minimally to total photosynthetic biomass. Despite their important role in the global cycling of nutrients, phytoplankton physiology and ecology are often highly simplified in global biogeochemical models. This dissertation elucidates the role of phytoplankton physiology and ecology within biogeochemical cycles, allowing for better characterization of marine microbial distribution and better representation of nutrient cycling for interpretive and predictive models. The development of formulations that link physiological responses …

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Submesoscale Dynamics Of Phytoplankton And Carbon Export Revealed By High-Resolution Airborne And Satellite Remote Sensing Of Currents And Ocean Color, Sarah E. Lang Jan 2026

Submesoscale Dynamics Of Phytoplankton And Carbon Export Revealed By High-Resolution Airborne And Satellite Remote Sensing Of Currents And Ocean Color, Sarah E. Lang

Open Access Dissertations

Satellites and airborne sensors reveal submesoscale (1 - 10 km) variability in ocean color in the form of filaments, eddies, and patches. The variability in ocean color is closely tied to the physical dynamics that restructure phytoplankton distributions and drive active biological responses like changes in primary productivity and community structure. As the base of the marine food web and a key component of the biological carbon pump, phytoplankton are crucial to the overall health of marine ecosystems and to the ocean's role in climate. This dissertation focuses on the use of airborne and satellite remote sensing to study the …

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Drivers Of Phytoplankton Bloom Interannual Variability In The Amundsen And Pine Island Polynyas, Guillaume Liniger, Delphine Lannuzel, Sébastien Moreau, Michael S. Dinniman, Peter G. Stutton Jan 2026

Drivers Of Phytoplankton Bloom Interannual Variability In The Amundsen And Pine Island Polynyas, Guillaume Liniger, Delphine Lannuzel, Sébastien Moreau, Michael S. Dinniman, Peter G. Stutton

CCPO Publications

The Amundsen Sea Embayment (ASE) experiences both the highest ice shelf melt rates and the highest biological productivity in West Antarctica. Using 19 years of satellite data and modelling output, we investigate the long-term influence of environmental factors on the phytoplankton bloom in the Amundsen Sea (ASP) and Pine Island (PIP) polynyas. We test the prevailing hypothesis that changes in ice shelf melt rate could drive interannual variability in the polynyas' surface chlorophyll-a (chl a) and Net Primary Productivity (NPP). We find that the interannual variability and long-term change in glacial meltwater may play an important role in …

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The Effects Of Varying Temperatures And Food Availability On The Reproductive Output Of The Acorn Barnacle: Chthamalus Fissus, Karina L. Rog Aug 2025

The Effects Of Varying Temperatures And Food Availability On The Reproductive Output Of The Acorn Barnacle: Chthamalus Fissus, Karina L. Rog

McNair Summer Research Program

Climate change is predicted to intensify ocean warming and the reduction in phytoplankton abundance, potentially disrupting reproductive processes in filter-feeding intertidal invertebrates. This study investigated the combined effects of water temperature increases and food availability on the reproductive output on Chthamalus fissus, a dominant intertidal barnacle species found along the Southern California coastline. Using a controlled laboratory experiment, adult barnacles collected from the nearshore rocky intertidal habitat in La Jolla, California, were exposed to two temperature regimes (ambient water temperature ~ 18°C and elevated water temperature ~ 20-21°C) and two food concentration treatments (low and high phytoplankton and rotifer …

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Organic Carbon Decay Mediated By A Mesopelagic Microbial Community: The Relevance Of Carbon Pools And Broad Biochemical Composition, Noah J. Craft, Alexander B. Bochdansky Jan 2025

Organic Carbon Decay Mediated By A Mesopelagic Microbial Community: The Relevance Of Carbon Pools And Broad Biochemical Composition, Noah J. Craft, Alexander B. Bochdansky

OES Faculty Publications

The mesopelagic zone is a site of strong microbially driven particle attenuation with depth and thus plays a crucial role in controlling the transfer efficiency of the ocean's biological pump. However, little quantitative information exists on the dependency of decay processes on the source material. Here we followed the decay of ¹⁴C-labeled dead particulate organic carbon (POC) and dissolved organic carbon (DOC) from three different phytoplankton species, and two incubations of live diatoms, in mesopelagic water over 3 months. Commonly used first-order kinetics failed to adequately describe the decay of organic material as rate constants varied from day to day. …

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Metabarcoding-Biomass Relationships And Internal Standards For Quantitative Dna Metabarcoding, Frances Webber Jan 2025

Metabarcoding-Biomass Relationships And Internal Standards For Quantitative Dna Metabarcoding, Frances Webber

Open Access Master's Theses

DNA metabarcoding has been widely adopted due to its power in investigating the composition of protistan communities, accurately identifying even small and cryptic taxa. However, the compositional nature of DNA metabarcoding results, and the distortion of natural abundances due to variation of the often-used 18S rRNA gene copy number over several orders of magnitude, renders these results semi-quantitative at best, limiting the application of DNA metabarcoding to ecological study. Here, we constructed mock communities from uni-algal cultures of taxonomically diverse phytoplankton and conducted metabarcoding using multiple primer sets and both DNA and cDNA as PCR templates. For each culture, chlorophyll …

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Quantifying Links Between Phytoplankton Physiology And The Environment, Gabrielle M. Armin Jan 2025

Quantifying Links Between Phytoplankton Physiology And The Environment, Gabrielle M. Armin

Open Access Dissertations

Phytoplankton are microscopic, primary producers in aquatic ecosystems worldwide. They are key links in global biogeochemical cycles, converting inorganic compounds into bioavailable nutrients which fuel fisheries. Through photosynthesis, phytoplankton play an essential role in the carbon cycle and marine biological pump, drawing carbon from the atmosphere, which is eventually sequestered in the oceans, regulating our Earth’s climate. Due to their influential role in large scale processes, there have been many efforts to characterize and quantify phytoplankton impacts to ecosystem health and global nutrient cycles. Often, phytoplankton physiology has been highly simplified in global or ecosystem models, limiting their representation to …

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Big Cells, Big Impact: Unravelling Seasonal Patterns Of Net Primary Production In Narragansett Bay, Dominique Jae Lockwood Jan 2025

Big Cells, Big Impact: Unravelling Seasonal Patterns Of Net Primary Production In Narragansett Bay, Dominique Jae Lockwood

Open Access Master's Theses

Net primary production is a measurement of available energy, or the amount of biomass that phytoplankton produce during photosynthesis that fuels marine food webs and drives carbon cycling. Despite its ecological importance, net primary production is relatively understudied in comparison to chlorophyll-a, which is often used as a proxy for biomass rather than productivity. In this study, we measured size-fractionated net primary production and chlorophyll-a concentrations in Narragansett Bay over a 14-month period from January 2022 to February 2023. Weekly surface water samples were collected and filtered to distinguish between small (> 10 μm) and large ( …

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Symbiodiniaceae Shifts Over The Last Decade On The Hottest Coral Reefs On Earth, Anna Fiesinger, Rachel Alderdice, Luigi Colin, Hannah Manns, Gabriela Perna, Kathryn H. Stankiewicz, Jacob J. Valenzuela, Line K. Bay, Daniel J. Barshis, Nitin S. Baliga, Iliana B. Baums, John A. Burt, Christian R. Voolstra Jan 2025

Symbiodiniaceae Shifts Over The Last Decade On The Hottest Coral Reefs On Earth, Anna Fiesinger, Rachel Alderdice, Luigi Colin, Hannah Manns, Gabriela Perna, Kathryn H. Stankiewicz, Jacob J. Valenzuela, Line K. Bay, Daniel J. Barshis, Nitin S. Baliga, Iliana B. Baums, John A. Burt, Christian R. Voolstra

Biological Sciences Faculty Publications

Corals in the Persian/Arabian Gulf (PAG) are resilient to various stressors, whose levels exceed those of coral reefs globally. These corals thereby offer insight into mechanisms underlying thermal resilience, e.g., regarding the role of endosymbiotic microalgae in the family Symbiodiniaceae. Previous studies have identified the thermotolerant species Cladocopium thermophilum as broadly associated with corals in the southern PAG. However, algal-host specificity at the within-species level and the temporal stability of these associations are not well understood. Here we sampled two dominant stony corals (Porites harrisoni, n = 119 and Platygyra daedalea, n = 79) at three sites …

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Seasonal Variability Of Surface Ocean Carbon Uptake And Chlorophyll-A Concentration In The West Antarctic Peninsula Over Two Decades, Jessica S. Turner, David R. Munro, Amanda Fay, Sharon Stammerjohn, Heather Kim, Oscar Schofield, Heidi Dierssen Jan 2025

Seasonal Variability Of Surface Ocean Carbon Uptake And Chlorophyll-A Concentration In The West Antarctic Peninsula Over Two Decades, Jessica S. Turner, David R. Munro, Amanda Fay, Sharon Stammerjohn, Heather Kim, Oscar Schofield, Heidi Dierssen

OES Faculty Publications

The Southern Ocean plays a vital role in global CO₂ uptake, but the magnitude and even the sign of the flux remain uncertain, and the influence of phytoplankton phenology is underexplored. This study focuses on the West Antarctic Peninsula, a region experiencing rapid climate change, to examine shifts in seasonal carbon uptake. Using 20 years of in situ air-sea CO₂ flux and satellite-derived Chlorophyll-a, we observe that the seasonal cycles of both air-sea CO₂ flux and Chlorophyll-a intensify poleward. The amplitude of the seasonal cycle of the non-thermal component of surface ocean pCO₂ increases with increasing latitude, while the amplitude …

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Assessing The Gut Content Of Styela Plicata: A Benthic Filter Feeder In The Indian River Lagoon, Honor Lily Triumph Edmands Jul 2024

Assessing The Gut Content Of Styela Plicata: A Benthic Filter Feeder In The Indian River Lagoon, Honor Lily Triumph Edmands

Theses and Dissertations

The Indian River Lagoon (IRL) has experienced declining water quality due to human activities involving nutrient input, leading to Harmful Algal Blooms (HABs). The Living Docks program affixes oyster mats to dock pilings to promote the settlement and recruitment of benthic filter feeders for water quality improvement. However, questions remain about filtering efficiencies of organisms that make up the mat communities, and whether organisms remove harmful species from the IRL. The pleated sea squirt, Styela plicata, is a common oyster mat resident. The goal of this thesis was to investigate what phytoplankton and bacteria S. plicata consumes, and if …

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Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Marine Cyanobacterium Synechococcus Sp. Ccmp 1334, Alyssa K. Sharbaugh Mar 2024

Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Marine Cyanobacterium Synechococcus Sp. Ccmp 1334, Alyssa K. Sharbaugh

LSU Master's Theses

The marine cyanobacterium Synechococcus sp. CCMP 1334 was grown in a continuous culture system on a 12:12 h light:dark cycle at all combinations of low and high pCO2 (400 and 1000 ppmv, respectively), nitrate availability (nitrate-limited and nutrient-replete conditions), and temperatures of 21°C, 24°C, 28°C, 32°C, and 35°C. The maximum median nutrient-replete growth rate was ~1.15 d−1 at 32 –35°C. Median growth rates at 1000 ppmv pCO2 were higher than those at 400 ppmv at all temperatures, but most of the differences were statistically insignificant. Carbon:nitrogen ratios were independent of pCO2 at a fixed relative growth rate but decreased with …

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The Impacts Of Anthropogenic Activity And Climate Change On The Formation Of Harmful Algal Blooms (Habs) And Its Ecological Consequence, Zhangxi Hu, Aifeng Li, Zhun Li, Margaret R. Mulholland Jan 2024

The Impacts Of Anthropogenic Activity And Climate Change On The Formation Of Harmful Algal Blooms (Habs) And Its Ecological Consequence, Zhangxi Hu, Aifeng Li, Zhun Li, Margaret R. Mulholland

OES Faculty Publications

No abstract provided.

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Submarine Groundwater Discharge As A Major Nutrient Source In River-Fed Vs. Tidally Dominated Estuaries, Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland Jan 2024

Submarine Groundwater Discharge As A Major Nutrient Source In River-Fed Vs. Tidally Dominated Estuaries, Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

The tidal tributaries of the lower Chesapeake Bay experience seasonally recurring harmful algal blooms and the significance of submarine groundwater discharge (SGD) as a nutrient vector is largely unknown. Here, we determined seasonal SGD nutrient loads in two tributaries with contrasting hydrodynamic conditions, river-fed (York River) vs. tidally dominated (Lafayette River). Radon surveys were performed in each river to quantify SGD at the embayment-scale during spring and fall 2021. Total SGD was determined from a ²²²Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm …

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Determining The Refractive Index Of Phytoplankton Via Direct Measurement Of Cellular Structures, Michael Kamowski May 2023

Determining The Refractive Index Of Phytoplankton Via Direct Measurement Of Cellular Structures, Michael Kamowski

Master's Theses

The refractive index of phytoplankton has never been directly measured before despite its importance towards studying the optical characteristics of marine particles. Previous attempts to measure it have been done through indirect methods. While these methods have proven useful, they contain assumptions about the particles morphology and composition that cause for uncertainty with the measurements. Through the use of the 3D Cell Explorer, a high precision holotomographic microscope, the RI of phytoplankton can be directly measured for the first time. With volume measurements, the phytoplankton were found to not display a single bulk RI, instead the bulk RI was different …

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Nitrite Cycling In The Primary Nitrite Maxima Of The Eastern Tropical North Pacific, Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, Karen L. Casciotti Jan 2023

Nitrite Cycling In The Primary Nitrite Maxima Of The Eastern Tropical North Pacific, Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, Karen L. Casciotti

OES Faculty Publications

The primary nitrite maximum (PNM) is a ubiquitous feature of the upper ocean, where nitrite accumulates in a sharp peak at the base of the euphotic zone. This feature is situated where many chemical and hydrographic properties have strong gradients and the activities of several microbial processes overlap. Near the PNM, four major microbial processes are active in nitrite cycling: ammonia oxidation, nitrite oxidation, nitrate reduction and nitrite uptake. The first two processes are mediated by the nitrifying archaeal/bacterial community, while the second two processes are primarily conducted by phytoplankton. The overlapping spatial habitats and substrate requirements for these microbes …

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The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane Jan 2023

The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane

OES Faculty Publications

It is widely assumed that phytoplankton abundance and productivity decline during temperate winters because of low irradiance and temperatures. However, winter phytoplankton blooms commonly occur in temperate estuaries, but they are often undocumented because of reduced water quality monitoring in winter. The small body of in situ work that has been done on winter blooms suggests they can be of enormous consequence to ecosystems. However, because monitoring is often reduced or stopped altogether during winter, it is unclear how widespread these blooms are or how long they can last. We analyzed an over 30-year record of monthly phytoplankton monitoring samples …

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Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins Jan 2023

Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins

OES Faculty Publications

The growth of diatoms in the Southern Ocean, especially the region surrounding the West Antarctic Peninsula, is frequently constrained by low dissolved iron and other trace metal concentrations. This challenge may be overcome by mutualisms between diatoms and co-occurring associated bacteria, in which diatoms produce organic carbon as a substrate for bacterial growth, and bacteria produce siderophores, metal-binding ligands that can supply diatoms with metals upon uptake as well as other useful secondary compounds for diatom growth like vitamins. To examine the relationships between diatoms and bacteria in the plankton (diatom) size class (> 3 mu m), we sampled both …

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Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams Jan 2023

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …

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A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton Jan 2023

A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton

OES Faculty Publications

The California Current System is a diatom‐dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …

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Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining Jan 2023

Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining

OES Faculty Publications

Particulate phases transport trace metals (TM) and thereby exert a major control on TM distribution in the ocean. Particulate TMs can be classified by their origin as lithogenic (crustal material), biogenic (cellular), or authigenic (formed in situ), but distinguishing these fractions analytically in field samples is a challenge often addressed using operational definitions and assumptions. These different phases require accurate characterization because they have distinct roles in the biogeochemical iron cycle. Particles collected from the upper 2,000 m of the northwest subtropical Atlantic Ocean over four seasonal cruises throughout 2019 were digested with a chemical leach to operationally distinguish labile …

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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 …

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Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken Jan 2023

Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken

CCPO Publications

Upward advection or mixing of iron-rich deep waters due to circulation changes driven by the rate of basal ice shelf melt was shown to be a primary control on chlorophyll a production in coastal polynyas over the Antarctic continental shelf. Here, the effects of atmospheric changes projected in 2100 on this relationship were examined with a 5-km resolution ocean/sea ice/ice shelf model of the Southern Ocean with different simulated dissolved iron sources and idealized biological uptake. The atmospheric changes are added as idealized increments to the forcing. Inclusion of a poleward shift and strengthening of the winds, increased precipitation, and …

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The Southern Ocean Ecosystem Affects The Entire World, Eugene J. Murphy, Nadine M. Johnston, Eileen E. Hofmann, Richard A. Phillips, Jennifer E. Jackson, Andrew J. Constable Jan 2023

The Southern Ocean Ecosystem Affects The Entire World, Eugene J. Murphy, Nadine M. Johnston, Eileen E. Hofmann, Richard A. Phillips, Jennifer E. Jackson, Andrew J. Constable

CCPO Publications

The Southern Ocean, which flows around the Antarctic continent, is home to vast numbers of unique and remarkable animals, including penguins, albatrosses, petrels, seals, and whales. The ocean bursts into life every spring, fueling a summer feeding and breeding frenzy. During the dark winter months, there is little food and life is very harsh. Human activities such as fishing and pollution are affecting this ecosystem, as is climate change. These ecosystem changes matter beyond the Southern Ocean! Ocean currents carry nutrients and organisms into and out of the Southern Ocean. Many marine mammals and seabirds swim or fly in and …

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Investigating The Relationship Between Dissolved Oxygen And Nitrate Concentration As A Proxy For Marine Ecosystem Health, Natalia M. Moore Dec 2022

Investigating The Relationship Between Dissolved Oxygen And Nitrate Concentration As A Proxy For Marine Ecosystem Health, Natalia M. Moore

Theses and Dissertations

Coastal environments such as seagrass meadows span a wide range of spatial scales and can experience disturbances that cause rapid shifts to ecosystem dynamics. Increased pressure to the coastal zone has highlighted the need for constant, real-time monitoring to monitor current ecosystem status. A custom, low cost, high resolution, in situ sensor network was designed and tested in the Lower Laguna Madre, Texas to characterize primary productivity in seagrass meadows through gradient patterns of dissolved oxygen concentration, with the purpose of determining whether seagrass or phytoplankton were the more dominant primary producer. There was a distinct vertical and horizontal gradient …

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Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao Jan 2022

Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao

OES Faculty Publications

Fully and accurately reconstructing changes in oceanic productivity and carbon export and their controls is critical to determining the efficiency of the biological pump and its role in the global carbon cycle through time, particularly in modern CO2 source regions like the eastern equatorial Pacific (EEP). Here we present new high-resolution records of sedimentary 230Th-normalized opal and nannofossil carbonate fluxes and [231Pa/230Th]xs ratios from site MV1014-02-17JC in the Panama Basin. We find that, across the last deglaciation, phytoplankton community structure is driven by changing patterns of nutrient (nitrate, iron, and silica) availability which, in …

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Imaging Technologies Build Capacity And Accessibility In Phytoplankton Species Identification Expertise For Research And Monitoring: Lessons Learned During The Covid-19 Pandemic, Sophie Clayton, Leah Gibala-Smith, Kathryn Mogatas, Chanel Flores-Vargas, Kayla Marciniak, Maci Wigginton, Margaret R. Mulholland Jan 2022

Imaging Technologies Build Capacity And Accessibility In Phytoplankton Species Identification Expertise For Research And Monitoring: Lessons Learned During The Covid-19 Pandemic, Sophie Clayton, Leah Gibala-Smith, Kathryn Mogatas, Chanel Flores-Vargas, Kayla Marciniak, Maci Wigginton, Margaret R. Mulholland

OES Faculty Publications

As primary producers, phytoplankton play an integral role in global biogeochemical cycles through their production of oxygen and fixation of carbon. They also provide significant ecosystem services, by supporting secondary production and fisheries. Phytoplankton biomass and diversity have been identified by the Global Ocean Observing System (GOOS) as Essential Ocean Variables (EOVs), properties that need to be monitored to better understand and predict the ocean system. Phytoplankton identification and enumeration relies on the skills and expertise of highly trained taxonomic analysts. The training of new taxonomic analysts is intensive and requires months to years of supervised training before an analyst …

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Microplankton Dynamics In The River-Dominated Mississippi Bight, Adam D. Boyette May 2021

Microplankton Dynamics In The River-Dominated Mississippi Bight, Adam D. Boyette

Dissertations

The Mississippi Bight (MSB) is a river-dominated continental margin influenced by multiple large river systems, including the Mississippi River, Alabama and Tombigbee rivers via Mobile Bay, and numerous smaller rivers, creeks, and bayous. This is part of a biologically-rich ecosystem that supports the second largest fishery industry by volume in the United States. Despite our understanding of the linkages between primary production with higher trophic levels, there remains limited studies quantifying these trophic interactions in this system. Microplankton (µm) community dynamics and trophic connectivity between primary producers and heterotrophic protists represent a critical nexus influencing overall biological productivity in this …

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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 …

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