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Current And Future Remote Sensing Of Harmful Algal Blooms In The Chesapeake Bay To Support The Shellfish Industry, Jl Wolny, Mc Tomlinson, S Schollaert Uz, Ta Egerton, Jr Mckay, A Meredith, Ks Reece, Gp Scott, Rp Stumpf May 2020

Current And Future Remote Sensing Of Harmful Algal Blooms In The Chesapeake Bay To Support The Shellfish Industry, Jl Wolny, Mc Tomlinson, S Schollaert Uz, Ta Egerton, Jr Mckay, A Meredith, Ks Reece, Gp Scott, Rp Stumpf

VIMS Articles

Harmful algal bloom (HAB) species in the Chesapeake Bay can negatively impact fish, shellfish, and human health via the production of toxins and the degradation of water quality. Due to the deleterious effects of HAB species on economically and environmentally important resources, such as oyster reef systems, Bay area resource managers are seeking ways to monitor HABs and water quality at large spatial and fine temporal scales. The use of satellite ocean color imagery has proven to be a beneficial tool for resource management in other locations around the world where high-biomass, nearly monospecific HABs occur. However, remotely monitoring HABs ...


Microplastics Affect Sedimentary Microbial Communities And Nitrogen Cycling, Meredith E. Seeley, Bk Song, Renia Passie, Robert C. Hale Jan 2020

Microplastics Affect Sedimentary Microbial Communities And Nitrogen Cycling, Meredith E. Seeley, Bk Song, Renia Passie, Robert C. Hale

VIMS Articles

Microplastics are ubiquitous in estuarine, coastal, and deep sea sediments. The impacts of microplastics on sedimentary microbial ecosystems and biogeochemical carbon and nitrogen cycles, however, have not been well reported. To evaluate if microplastics influence the composition and function of sedimentary microbial communities, we conducted a microcosm experiment using salt marsh sediment amended with polyethylene (PE), polyvinyl chloride(PVC), polyurethane foam (PUF) or polylactic acid (PLA) microplastics. We report that the presence of microplastics alters sediment microbial community composition and nitrogen cycling processes. Compared to control sediments without microplastic, PUF- and PLA-amended sediments promote nitrification and denitrification, while PVC amendment ...


Multidisciplinary Observing In The World Ocean's Oxygen Minimum Zone Regions: From Climate To Fish - The Voice Initiative, V Garcon, J Karstensen, A Palacz, Et Al, Kevin C. Weng Dec 2019

Multidisciplinary Observing In The World Ocean's Oxygen Minimum Zone Regions: From Climate To Fish - The Voice Initiative, V Garcon, J Karstensen, A Palacz, Et Al, Kevin C. Weng

VIMS Articles

Multidisciplinary ocean observing activities provide critical ocean information to satisfy ever-changing socioeconomic needs and require coordinated implementation. The upper oxycline (transition between high and low oxygen waters) is fundamentally important for the ecosystem structure and can be a useful proxy for multiple observing objectives connected to eastern boundary systems (EBSs) that neighbor oxygen minimum zones (OMZs). The variability of the oxycline and its impact on the ecosystem (VOICE) initiative demonstrates how societal benefits drive the need for integration and optimization of biological, biogeochemical, and physical components of regional ocean observing related to EBS. In liaison with the Global Ocean Oxygen ...


Global Change Effects On Plant Communities Are Magnified By Time And The Number Of Global Change Factors Imposed, Kj Komatsu, Ml Avolio, Et Al, David S. Johnson, Et Al Sep 2019

Global Change Effects On Plant Communities Are Magnified By Time And The Number Of Global Change Factors Imposed, Kj Komatsu, Ml Avolio, Et Al, David S. Johnson, Et Al

VIMS Articles

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (< 10 y). In contrast, long-term (>= 10 y) experiments show increasing community divergence of treatments from ...


Toward A Coordinated Global Observing System For Seagrasses And Marine Macroalgae, J. Emmett Duffy, L. Benedetti-Cecchi, Et Al, Robert J. Orth, Et Al Jul 2019

Toward A Coordinated Global Observing System For Seagrasses And Marine Macroalgae, J. Emmett Duffy, L. Benedetti-Cecchi, Et Al, Robert J. Orth, Et Al

VIMS Articles

In coastal waters around the world, the dominant primary producers are benthic macrophytes, including seagrasses and macroalgae, that provide habitat structure and food for diverse and abundant biological communities and drive ecosystem processes. Seagrass meadows and macroalgal forests play key roles for coastal societies, contributing to fishery yields, storm protection, biogeochemical cycling and storage, and important cultural values. These socio-economically valuable services are threatened worldwide by human activities, with substantial areas of seagrass and macroalgal forests lost over the last half-century. Tracking the status and trends in marine macrophyte cover and quality is an emerging priority for ocean and coastal ...


Mechanisms Involving Sensory Pathway Steps Inform Impacts Of Global Climate Change On Ecological Processes, Emily B. Rivest, Brittany Jellison, Gabriel Ng, Et Al Jul 2019

Mechanisms Involving Sensory Pathway Steps Inform Impacts Of Global Climate Change On Ecological Processes, Emily B. Rivest, Brittany Jellison, Gabriel Ng, Et Al

VIMS Articles

Human-caused environmental change will have significant non-lethal and indirect impacts on organisms due to altered sensory pathways, with consequences for ecological interactions. While a growing body of work addresses how global ocean change can impair the way organisms obtain and use information to direct their behavior, these efforts have typically focused on one step of the pathway (e.g., reception of a cue/signal), one sensory modality (e.g., visual), or one environmental factor (e.g., temperature). An integrated view of how aspects of environmental change will impact multiple sensory pathways and related ecological processes is needed to better anticipate ...


Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, Molly Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, Jon Derek Loftis, John D. Boon, David M. Malmquist Jun 2019

Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, Molly Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, Jon Derek Loftis, John D. Boon, David M. Malmquist

VIMS Articles

As communities grapple with rising seas and more frequent flooding events, they need improved projections of future rising and flooding over multiple time horizons, to assist in a multitude of planning efforts. There are currently a few different tools available that communities can use to plan, including the Sea Level Report Card and products generated by a United States. Federal interagency task force on sea level rise. These tools are a start, but it is recognized that they are not necessarily enough at present to provide communities with the type of information needed to support decisions that range from seasonal ...


A Data-Driven Modeling Approach For Simulating Algal Blooms In The Tidal Freshwater Of James River In Response To Riverine Nutrient Loading, Jian Shen, Qubin Qin, Ya Wang, Mac Sisson Apr 2019

A Data-Driven Modeling Approach For Simulating Algal Blooms In The Tidal Freshwater Of James River In Response To Riverine Nutrient Loading, Jian Shen, Qubin Qin, Ya Wang, Mac Sisson

VIMS Articles

Algal blooms often occur in the tidal freshwater (TF) of the James River estuary, a tributary of the Chesapeake Bay. The timing of algal blooms correlates highly to a summer low-flow period when residence time is long and nutrients are available. Because of complex interactions between physical transport and algal dynamics, it is challenging to predict interannual variations of bloom correctly using a complex eutrophication model without having ahigh-resolution model gridto resolve complexgeometryand anaccurate estimate of nutrientloading to drive the model. In this study, an approach using long-term observational data (from 1990 to 2013) and the Support vector machine (LS-SVM ...


Restoring The Eastern Oyster: How Much Progress Has Been Made In 53 Years?, Ab Hernandez, Rd Brumbaugh, P Fredrick, R Grizzle, Mark Luckenbach, Ch Peterson, C Angelini Oct 2018

Restoring The Eastern Oyster: How Much Progress Has Been Made In 53 Years?, Ab Hernandez, Rd Brumbaugh, P Fredrick, R Grizzle, Mark Luckenbach, Ch Peterson, C Angelini

VIMS Articles

Coastal ecosystem restoration is accelerating globally as a means of enhancing shoreline protection, carbon storage, water quality, fisheries, and biodiversity. Among the most substantial of these efforts have been those focused on re-establishing oyster reefs across the US Atlantic and Gulf coasts. Despite considerable investment, it is unclear how the scale of and approaches toward oyster restoration have evolved. A synthesis of 1768 projects undertaken since 1964 reveals that oyster substrate restoration efforts have primarily been concentrated in the Chesapeake Bay and the Gulf Coast, have been heavily reliant on oyster shell, and have re-established 4.5% of the reef ...


Living Shorelines Support Nearshore Benthic Communities In Upper And Lower Chesapeake Bay, Tm Davenport, Rd Seitz, Ke Knick, N Jackson Sep 2018

Living Shorelines Support Nearshore Benthic Communities In Upper And Lower Chesapeake Bay, Tm Davenport, Rd Seitz, Ke Knick, N Jackson

VIMS Articles

Human population growth and sea-level rise are increasing the demand for protection of coastal property against shoreline erosion. Living shorelines are designed to provide shoreline protection and are constructed or reinforced using natural elements. While living shorelines are gaining popularity with homeowners, their ability to provide ecological services (e.g., habitat provision and trophic transfer) is not well understood, and information is needed to improve coastal and resource management decision-making. We examined benthic community responses to living shorelines in two case-study subestuaries of Chesapeake Bay using a before-after control-impact study design. At Windy Hill, a bulkhead was removed and replaced ...


Host And Symbionts In Pocillopora Damicornis Larvae Display Different Transcriptomic Responses To Ocean Acidification And Warming, Emily B. Rivest, Morgan B. Kelly, Melissa B. Debiasse, Gretchen E. Hofmann May 2018

Host And Symbionts In Pocillopora Damicornis Larvae Display Different Transcriptomic Responses To Ocean Acidification And Warming, Emily B. Rivest, Morgan B. Kelly, Melissa B. Debiasse, Gretchen E. Hofmann

VIMS Articles

As global ocean change progresses, reef-building corals and their early life history stages will rely on physiological plasticity to tolerate new environmental conditions. Larvae from brooding coral species contain algal symbionts upon release, which assist with the energy requirements of dispersal and metamorphosis. Global ocean change threatens the success of larval dispersal and settlement by challenging the performance of the larvae and of the symbiosis. In this study, larvae of the reef-building coral Pocillopora damicornis were exposed to elevated pCO2 and temperature to examine the performance of the coral and its symbionts in situ and better understand the mechanisms of ...


Consequences Of Drift And Carcass Decomposition For Estimating Sea Turtle Mortality Hotspots, Bianca Santos, David M. Kaplan, Marjorie A.M. Friedrichs, Susan G. Barco, Katherine L. Mansfield, James P. Manning Jan 2018

Consequences Of Drift And Carcass Decomposition For Estimating Sea Turtle Mortality Hotspots, Bianca Santos, David M. Kaplan, Marjorie A.M. Friedrichs, Susan G. Barco, Katherine L. Mansfield, James P. Manning

VIMS Articles

Sea turtle strandings provide important mortality information, yet knowledge of turtle carcass at-sea drift and decomposition characteristics are needed to better understand and manage where these mortalities occur. We used empirical sea turtle carcass decomposition and drift experiments in the Chesapeake Bay, Virginia, USA to estimate probable carcass oceanic drift times and quantify the impact of direct wind forcing on carcass drift. Based on the time period during which free-floating turtle carcasses tethered nearshore were buoyant, we determined that oceanic drift duration of turtle carcasses was highly dependent on water temperature and varied from 2 to 15 days during typical ...


Sea Level Rise May Increase Extinction Risk Of A Saltmarsh Ontogenetic Habitat Specialist, David S. Johnson, Bethany L. Williams Aug 2017

Sea Level Rise May Increase Extinction Risk Of A Saltmarsh Ontogenetic Habitat Specialist, David S. Johnson, Bethany L. Williams

VIMS Articles

Specialist species are more vulnerable to environmental change than generalist species. For species with ontogenetic niche shifts, specialization may occur at a particular life stage making those stages more susceptible to environmental change. In the salt marshes in the northeast U.S., accelerated sea level rise is shifting vegetation patterns from flood-intolerant species such as Spartina patens to the flood-tolerant Spartina alterniflora. We tested the potential impact of this change on the coffee bean snail, Melampus bidentatus, a numerically dominant benthic invertebrate with an ontogenetic niche shift. From a survey of eight marshes throughout the northeast U.S., small snails ...


Multifaceted Biodiversity Hotspots Of Marine Mammals For Conservation Priorities, Camille Albouy, Valentine L. Delattre, Bastien Merigot, Christine N. Meynard, Fabien Leprieur May 2017

Multifaceted Biodiversity Hotspots Of Marine Mammals For Conservation Priorities, Camille Albouy, Valentine L. Delattre, Bastien Merigot, Christine N. Meynard, Fabien Leprieur

VIMS Articles

Aim: Identifying the multifaceted biodiversity hotspots for marine mammals and their spatial overlap with human threats at the global scale.


A Synergistic Approach For Evaluating Climate Model Output For Ecological Applications, Rd Cavanaugh, Ej Murphy, Et Al, Walker O. Smith Jr., Et Al Jan 2017

A Synergistic Approach For Evaluating Climate Model Output For Ecological Applications, Rd Cavanaugh, Ej Murphy, Et Al, Walker O. Smith Jr., Et Al

VIMS Articles

Increasing concern about the impacts of climate change on ecosystems is prompting ecologists and ecosystem managers to seek reliable projections of physical drivers of change. The use of global climate models in ecology is growing, although drawing ecologically meaningful conclusions can be problematic. The expertise required to access and interpret output from climate and earth system models is hampering progress in utilizing them most effectively to determine the wider implications of climate change. To address this issue, we present a joint approach between climate scientists and ecologists that explores key challenges and opportunities for progress. As an exemplar, our focus ...


Assessing The Impact Of Local And Regional Influences On Nitrogen Loads To Buzzards Bay, Ma, Shanna C. Williamson, Jennie E. Rheuban, Et Al Jan 2017

Assessing The Impact Of Local And Regional Influences On Nitrogen Loads To Buzzards Bay, Ma, Shanna C. Williamson, Jennie E. Rheuban, Et Al

VIMS Articles

Nitrogen and chlorophyll-a concentrations in estuarine systems often correlate positively with increased nitrogen input. To determine the interactions between nitrogen load, physical drivers, and water quality indicators, we estimated nitrogen inputs to 28 estuaries within the Buzzards Bay, Massachusetts (USA) watershed from 1985 to 2013. Estimates were derived by combining parcel specific wastewater disposal, point source wastewater discharge, land use, and atmospheric nitrogen deposition data with a previously verified nitrogen loading model. Linear regression analysis was used to quantify temporal trends in individual data sets and characterize relationships between variables. The land-use data indicated that fractional coverage of impervious surfaces ...


Prediction Of The Export And Fate Of Global Ocean Net Primary Production: The Exports Science Plan, Da Siegel, Ko Buesseler, Et Al, Deborah K. Steinberg Jan 2016

Prediction Of The Export And Fate Of Global Ocean Net Primary Production: The Exports Science Plan, Da Siegel, Ko Buesseler, Et Al, Deborah K. Steinberg

VIMS Articles

Ocean ecosystems play a critical role in the Earth's carbon cycle and the quantification of their impacts for both present conditions and for predictions into the future remains one of the greatest challenges in oceanography. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS) Science Plan is to develop a predictive understanding of the export and fate of global ocean net primary production (NPP) and its implications for present and future climates. The achievement of this goal requires a quantification of the mechanisms that control the export of carbon from the euphotic zone as well ...


Why Biodiversity Is Important To The Functioning Of Real-World Ecosystems, Da Siegel, Ko Buessler, Et Al, Deborah K. Steinberg Jan 2016

Why Biodiversity Is Important To The Functioning Of Real-World Ecosystems, Da Siegel, Ko Buessler, Et Al, Deborah K. Steinberg

VIMS Articles

Ocean ecosystems play a critical role in the Earth's carbon cycle and the quantification of their impacts for both present conditions and for predictions into the future remains one of the greatest challenges in oceanography. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS) Science Plan is to develop a predictive understanding of the export and fate of global ocean net primary production (NPP) and its implications for present and future climates. The achievement of this goal requires a quantification of the mechanisms that control the export of carbon from the euphotic zone as well ...


Influence Of Reservoir Infill On Coastal Deep Water Hypoxia, Lewis C. Linker, Richard A. Batiuk, Carl F. Cerco, Gary W. Shenk, Richard Tian, Ping Wang, Guido Yactayo Jan 2016

Influence Of Reservoir Infill On Coastal Deep Water Hypoxia, Lewis C. Linker, Richard A. Batiuk, Carl F. Cerco, Gary W. Shenk, Richard Tian, Ping Wang, Guido Yactayo

VIMS Articles

Ecological restoration of the Chesapeake through the Chesapeake Bay total maximum daily load (TMDL) requires the reduction of nitrogen, phosphorus, and sediment loads in the Chesapeake watershed because of the tidal water quality impairments and damage to living resources they cause. Within the Chesapeake watershed, the Conowingo Reservoir has been filling in with sediment for almost a century and is now in a state of near‐full capacity called dynamic equilibrium. The development of the Chesapeake TMDL in 2010 was with the assumption that the Conowingo Reservoir was still effectively trapping sediment and nutrients. This is now known not to ...


Historical Summer Distribution Of The Endangered North Atlantic Right Whale (Eubalaena Glacialis): A Hypothesis Based On Environmental Preferences Of A Congeneric Species, Sophie Monserrat, Maria G. Pennino, Tim D. Smith, Randall R. Reeves, Christine N. Meynard, David M. Kaplan, Ana S.L. Rodrigues Aug 2015

Historical Summer Distribution Of The Endangered North Atlantic Right Whale (Eubalaena Glacialis): A Hypothesis Based On Environmental Preferences Of A Congeneric Species, Sophie Monserrat, Maria G. Pennino, Tim D. Smith, Randall R. Reeves, Christine N. Meynard, David M. Kaplan, Ana S.L. Rodrigues

VIMS Articles

Aim: To obtain a plausible hypothesis for the historical distribution of North Atlantic right whales (NARWs) (Eubalaena glacialis) in their summer feeding grounds. Previously widespread in the North Atlantic, after centuries of hunt- ing, these whales survive as a small population off eastern North America. Because their exploitation began before formal records started, information about their historical distribution is fragmentary.


Representing Taxonomic, Phylogenetic And Functional Diversity: New Challenges For Mediterranean Marine-Protected Areas, Francois Guilhaumon, Camille Albouy, Et Al, Christine N. Meynard Feb 2015

Representing Taxonomic, Phylogenetic And Functional Diversity: New Challenges For Mediterranean Marine-Protected Areas, Francois Guilhaumon, Camille Albouy, Et Al, Christine N. Meynard

VIMS Articles

To assess gaps in the representation of taxonomic, phylogenetic and func- tional diversity among coastal fishes in Mediterranean marine-protected areas (MPAs).


Scientific Evidence Supports A Ban On Microbeads, Cm Rochman, Sm Kross, Jb Armstrong, Mt Bogan, Es Darling, Sj Green, Ar Smyth, D Verissimo Jan 2015

Scientific Evidence Supports A Ban On Microbeads, Cm Rochman, Sm Kross, Jb Armstrong, Mt Bogan, Es Darling, Sj Green, Ar Smyth, D Verissimo

VIMS Articles

No abstract provided.


Projected Hg Dietary Exposure Of 3 Bird Species Nesting On A Contaminated Floodplain (South River, Virginia, Usa), Jc Wang, Mc Newman Jan 2013

Projected Hg Dietary Exposure Of 3 Bird Species Nesting On A Contaminated Floodplain (South River, Virginia, Usa), Jc Wang, Mc Newman

VIMS Articles

Dietary Hg exposure was modeled for Carolina wren (Thryothorus ludovicianus), Eastern song sparrow (Melospiza melodia), and Eastern screech owl (Otus asio) nesting on the contaminated South River floodplain (Virginia, USA). Parameterization of Monte-Carlo models required formal expert elicitation to define bird body weight and feeding ecology characteristics because specific information was either unavailable in the published literature or too difficult to collect reliably by field survey. Mercury concentrations and weights for candidate food items were obtained directly by field survey. Simulations predicted the probability that an adult bird during breeding season would ingest specific amounts of Hg during daily foraging ...


Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, M. J. Church, H. W. Ducklow, Et Al Jan 2006

Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, M. J. Church, H. W. Ducklow, Et Al

VIMS Articles

Heterotrophic microbial production is a fundamental determinant in the flow of bioelements and energy within the pelagic ecosystems of the open ocean. To characterize the temporal dynamics in rates of heterotrophic picoplankton production (HPP), we examined vertical profiles of H-3-leucine (H-3-leu) and [methyl-H-3]-thymidine (H-3-TdR) incorporation at Stn ALOHA (22 degrees 45'N, 158 degrees W) in the oligotrophic North Pacific Ocean. Euphotic zone rates of H-3-leu and H-3-TdR incorporation were measured in situ under light and dark conditions on cruises to Stn ALOHA between April 2000 and August 2005. Rates of H-3-leu and H-3-TdR incorporation were elevated in the ...


Liver Carcinogenesis In A Non-Migratory Fish: The Association With Polycyclic Aromatic Hydrocarbon Exposure, W. K. Vogelbein, M. A. Unger Jan 2006

Liver Carcinogenesis In A Non-Migratory Fish: The Association With Polycyclic Aromatic Hydrocarbon Exposure, W. K. Vogelbein, M. A. Unger

VIMS Articles

Field and laboratory studies indicate a strong positive association between exposure to chemical pollutants in aquatic environments and development of neoplasia in fishes. This brief communication reviews some of the more important North American and European studies that have been conducted on this relationship. We then review work conducted on a small nonmigratory estuarine cyprinodontid teleost fish, the mummichog (Fundulus heteroclitus) in the industrialized Elizabeth River, Virginia USA. Histopathological surveys of mummichogs from variously degraded habitats indicate an association between PAH exposure and development of neoplasia. We have observed non-neoplastic lesions, preneoplasms and hepatic, biliary, exocrine pancreatic and vascular neoplasms ...


A Perspective On Two Decades Of Policies And Regulations Influencing The Protection And Restoration Of Submerged Aquatic Vegetation In Chesapeake Bay, Usa, R J. Orth, Ra Batiuk, Pw Bergstrom, Ken Moore Nov 2002

A Perspective On Two Decades Of Policies And Regulations Influencing The Protection And Restoration Of Submerged Aquatic Vegetation In Chesapeake Bay, Usa, R J. Orth, Ra Batiuk, Pw Bergstrom, Ken Moore

VIMS Articles

Seagrasses along with many other species of freshwater rooted submerged macrophytes in Chesapeake Bay (collectively called SAV) underwent serious declines in population abundances in the 1970s and have not as yet rebounded to previous levels. Cooperative efforts by scientists, politicians, federal and state resource managers, and the general public have developed policies and plans to protect, preserve and enhance SAV populations of Chesapeake Bay. These include the Chesapeake Bay Agreements (1983, 1987, 1992, 1993, 2000), an SAV Management Policy and Implementation Plan for Chesapeake Bay and Tidal Tributaries (1989 and 1990), Chesapeake Bay Blue Crab Fishery Management Plan (1997), as ...


Photochemical Production Of Dissolved Inorganic Nitrogen And Primary Amines From Dissolved Organic Nitrogen In Waters Of Two Estuaries And Adjacent Surficial Groundwaters, Dj Koopmans, Da Bronk Jan 2002

Photochemical Production Of Dissolved Inorganic Nitrogen And Primary Amines From Dissolved Organic Nitrogen In Waters Of Two Estuaries And Adjacent Surficial Groundwaters, Dj Koopmans, Da Bronk

VIMS Articles

Recent studies have shown that in a number of humic-rich surface waters in North America, NH4+ is released when dissolved organic matter (DOM) is exposed to sunlight. However, photochemical NH4+ production has not been observed in all surface waters, and factors that contribute to it are not well understood. We hypothesized that the presence or absence of NH4+ photoproduction may be affected by the light exposure history of DOM, The present study was undertaken to determine whether DOM from surficial groundwaters, with minimal light exposure history, would produce labile nitrogen (N) photoproducts more consistently, In this study, estuarine surface waters ...


Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr. Jan 2002

Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr.

VIMS Articles

The photosynthetic parameters of natural phytoplankton assemblages from the Ross Sea, Antarctica, as well as unialgal cultures of the diatom Pseudonitzschia sp. and the colonial haptophyte Phaeocystis antarctica were investigated to determine if differential responses to irradiance could explain the distribution of phytoplankton in the Ross Sea. Field assemblages had photosynthetic responses that suggested acclimation to low irradiance levels, and the initial rate of photosynthesis per unit chlorophyll (a) and the theoretical maximum rate of production (p(max)(B)) averaged 0,083 mg C (mg chl a)(-1) h(-1) (mumol m(-2) s(-1))(-1) and 2,40 mg ...


Changes In Bacterioplankton Metabolic Capabilities Along A Salinity Gradient In The York River Estuary, Virginia, Usa, G. E. Schultz, H. W. Ducklow Sep 2000

Changes In Bacterioplankton Metabolic Capabilities Along A Salinity Gradient In The York River Estuary, Virginia, Usa, G. E. Schultz, H. W. Ducklow

VIMS Articles

Changes in metabolic capabilities of bacterial communities along the estuarine salinity gradient may affect the extent of organic matter processing and bacterial growth and accumulation during transit through the system; As part of a larger study of estuarine microbial processes, we attempted to quantify differences in bacterial community structure using Biolog plates. Biolog GN plates (Biolog, Inc., Hayward, CA, USA) were used to determine differences in bacterioplankton community metabolic potential. Biolog GN microplates are 96-well microtiter plates in which each well contains an individual carbon source as well the redox dye tetrazolium violet. As bacteria grow and oxidize each substrate ...


Estimation Of Bacterial Respiration And Growth Efficiency In The Ross Sea, Antarctica, C. A. Carlson, N. R. Bates, H. W. Ducklow, D. A. Hansell Jan 1999

Estimation Of Bacterial Respiration And Growth Efficiency In The Ross Sea, Antarctica, C. A. Carlson, N. R. Bates, H. W. Ducklow, D. A. Hansell

VIMS Articles

Seawater cultures were conducted in large volume (36 l) gas impermeable tri-laminate bags for the purpose of empirically deriving bacterial growth efficiency (BGE) and carbon conversion factors (CCF) in the south central Ross Sea. This experimental design allowed for concomitant measurements of metabolic reactants (loss of total and dissolved organic carbon [TOC and DOG]) and products (gain of total carbon dioxide [TCO2] and bacterial biomass) to be made from a single incubation vessel. Some previous studies have relied on proxy measurements (e.g. O-2, H-3-thymidine incorporation and cell abundance) to determine BGE and CCF rather than direct carbon measurements. Our ...