Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 18 of 18
Full-Text Articles in Life Sciences
Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Karen G. Burnett, Lisa J. Bain, William S. Baldwin, (…), Peter A. Van Veld, Wolfgang K. Vogelbein
Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Karen G. Burnett, Lisa J. Bain, William S. Baldwin, (…), Peter A. Van Veld, Wolfgang K. Vogelbein
VIMS Articles
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these …
Biodiversity Mediates Productivity Through Different Mechanisms At Adjacent Trophic Levels, Zt Long, Jf Bruno, Je Duffy
Biodiversity Mediates Productivity Through Different Mechanisms At Adjacent Trophic Levels, Zt Long, Jf Bruno, Je Duffy
VIMS Articles
Biodiversity may enhance productivity either because diverse communities more often contain productive species (selection effects) or because they show greater complementarity in resource use. Our understanding of how these effects influence community production comes almost entirely from studies of plants. To test whether previous results apply to higher trophic levels, we first used simulations to derive expected contributions of selection and complementarity to production in competitive assemblages defined by either neutral interactions, dominance, or a trade-off between growth and competitive ability. The three types of simulated assemblages exhibited distinct interaction signatures when diversity effects were partitioned into selection and complementarity …
Eutrophication In Shallow Coastal Bays And Lagoons: The Role Of Plants In The Coastal Filter, Karen J. Mcglathery, Kristina Sundback, Iris C. Anderson
Eutrophication In Shallow Coastal Bays And Lagoons: The Role Of Plants In The Coastal Filter, Karen J. Mcglathery, Kristina Sundback, Iris C. Anderson
VIMS Articles
Nutrient loading to coastal bay ecosystems is of a similar magnitude as that to deeper, river-fed estuaries, yet our understanding of the eutrophication process in these shallow systems lags far behind. In this synthesis, we focus on one type of biotic feedback that influences eutrophication patterns in coastal bays — the important role of primary producers in the ‘coastal filter’. We discuss the 2 aspects of plant-mediated nutrient cycling as eutrophication induces a shift in primary producer dominance: (1) the fate of nutrients bound in plant biomass, and (2) the effects of primary producers on biogeochemical processes that influence nutrient …
The Functional Role Of Biodiversity In Ecosystems: Incorporating Trophic Complexity, J. Emmett Duffy, Bradley J. Cardinale, Kristin E. France, Peter B. Mcintyre, Elisa Thebault, Michel Loreau
The Functional Role Of Biodiversity In Ecosystems: Incorporating Trophic Complexity, J. Emmett Duffy, Bradley J. Cardinale, Kristin E. France, Peter B. Mcintyre, Elisa Thebault, Michel Loreau
VIMS Articles
Understanding how biodiversity affects functioning of ecosystems requires integrating diversity within trophic levels (horizontal diversity) and across trophic levels (vertical diversity, including food chain length and omnivory). We review theoretical and experimental progress toward this goal. Generally, experiments show that biomass and resource use increase similarly with horizontal diversity of either producers or consumers. Among prey, higher diversity often increases resistance to predation, due to increased probability of including inedible species and reduced efficiency of specialist predators confronted with diverse prey. Among predators, changing diversity can cascade to affect plant biomass, but the strength and sign of this effect depend …
Biodiversity And Food Web Structure Influence Short-Term Accumulation Of Sediment Organic Matter In An Experimental Seagrass System, Elizabeth A. Canuel, Ac Spivak, Ej Waterson, Je Duffy
Biodiversity And Food Web Structure Influence Short-Term Accumulation Of Sediment Organic Matter In An Experimental Seagrass System, Elizabeth A. Canuel, Ac Spivak, Ej Waterson, Je Duffy
VIMS Articles
We tested the effects of grazer diversity and food chain length on the quantity and quality of accumulated sediment organic matter (SOM) in experimental eelgrass (Zostera marina) mesocosms. By use of a factorial manipulation of crustacean grazer species richness and predator presence, we examined the effects of epibenthic consumers on SOM composition by using stable carbon isotopes (delta C-13) and lipid biomarker compounds. Grazer species composition strongly influenced nearly all measures of SOM quantity and quality. In particular, increased densities of the grazing amphipod, Gammarus mucronatus, decreased accumulation of benthic microalgae (chlorophyll a) and the relative abundance of polyunsaturated fatty …
Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A.M. Friedrichs, Et Al.
Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A.M. Friedrichs, Et Al.
VIMS Articles
[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models' performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted …
Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, Matthew Church, Hugh Ducklow, Rm Letelier, David Karl
Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, Matthew Church, Hugh Ducklow, Rm Letelier, David Karl
VIMS Articles
The marine ecosystem of the West Antarctic Peninsula (WAP) extends from the Bellingshausen Sea to the northern tip of the peninsula and from the mostly glaciated coast across the continental shelf to the shelf break in the west. The glacially sculpted coastline along the peninsula is highly convoluted and characterized by deep embayments that are often interconnected by channels that facilitate transport of heat and nutrients into the shelf domain. The ecosystem is divided into three subregions, the continental slope, shelf and coastal regions, each with unique ocean dynamics, water mass and biological distributions. The WAP shelf lies within the …
Top-Down Control Of Phytoplankton By Oysters In Chesapeake Bay, Usa: Reply To Newell Et Al. (2007), Lawrence R. Pomeroy, Christopher F. D'Elia, Linda C. Schaffner
Top-Down Control Of Phytoplankton By Oysters In Chesapeake Bay, Usa: Reply To Newell Et Al. (2007), Lawrence R. Pomeroy, Christopher F. D'Elia, Linda C. Schaffner
VIMS Articles
Recently published models, which allow for spatial and temporal matching of oyster and phytoplankton populations in mainstream Chesapeake Bay, support the conclusion of Pomeroy et al. (2006; Mar Ecol Prog Ser 325:301-309) that oysters cannot, and could not, control the spring blooms that are the ultimate cause of summer hypoxia. We enlarge upon our earlier exposition of how top-down and bottom-up processes interact in Chesapeake Bay to permit the occurrence of phytoplankton blooms in spring, but not in summer.
Supplemental Effects Of Diet Mixing On Absorption Of Ingested Organic Carbon In The Marine Copepod Acartia Tonsa, Peter Thor, Marja Koski, Kam W. Tang, Sigrun H. Jonasdottir
Supplemental Effects Of Diet Mixing On Absorption Of Ingested Organic Carbon In The Marine Copepod Acartia Tonsa, Peter Thor, Marja Koski, Kam W. Tang, Sigrun H. Jonasdottir
VIMS Articles
We investigated increased carbon absorption efficiencies (AEs) as a possible cause for positive effects of diet mixing on copepod egg production rates (EPRs) and hatching success (EHS). Female Acartia tonsa were fed C-14/Cr-51 dual-labelled Dunaliella tertiolecta (Dun), Amphidinium carterae (Amp), Phaeocystis globosa (Pha), and 3 pairwise 1: 1 mixes of the 3 diets. AEs, derived from the ratios of labels in algae and copepod faecal pellets, were 44% on Dun, 37% on Amp, and 49% on Pha, but increased significantly to 61% on Dun + Amp. As a result, EPRs remained low in all tested diets except for Dun + …
Top-Down And Bottom-Up Controls On Sediment Organic Matter Composition In An Experimental Seagrass Ecosystem, Ac Spivak, Elizabeth A. Canuel, Je Duffy, Jp Richardson
Top-Down And Bottom-Up Controls On Sediment Organic Matter Composition In An Experimental Seagrass Ecosystem, Ac Spivak, Elizabeth A. Canuel, Je Duffy, Jp Richardson
VIMS Articles
We tested the singular and interactive effects of resource availability (light) and community composition (food chain length and herbivore species richness) on eelgrass (Zostera marina) ecosystem properties and functioning with an experimental mesocosm system. Food chain length was manipulated through the presence or absence of blue crab (Callinectes sapidus) predators, whereas grazer species richness varied across three levels (zero, two, or four crustacean species). We found important and interacting effects of bottom-up and top-down forcings on sediment organic matter (SOM) composition. Light increased eelgrass and algal biomass and sediment organic carbon and nitrogen content. Increasing grazer diversity generally decreased algal …
Taxonomic Composition And Growth Rates Of Phytoplankton Assemblages At The Subtropical Convergence East Of New Zealand, L Delizo, Walker O. Smith Jr., J Hall
Taxonomic Composition And Growth Rates Of Phytoplankton Assemblages At The Subtropical Convergence East Of New Zealand, L Delizo, Walker O. Smith Jr., J Hall
VIMS Articles
Off the eastern coast of New Zealand, warm, saline, nutrient-poor Subtropical Waters (STW) are separated from. cool, fresher, relatively nutrient-rich Sub-Antarctic Waters (SAW) by the Subtropical Convergence (STC). The Chatham Rise, a submarine rise, restricts. the latitudinal movement of the STC as well as mixing of STW and SAW Due to this restriction, this sector of the STC is characterized by sharp gradients in temperature, macro-(nitrate, silicate and phosphate) and micro- (iron) nutrient concentrations. Shipboard incubations were conducted during austral spring 2000 and 2001 to test the hypothesis that these gradients affect the taxonomic composition and/or growth rates of phytoplankton …
Comparison Of Plankton Catch By Three Light-Trap Designs In The Northern Gulf Of Mexico, Richard F. Shaw, Joseph S. Cope, G. Joan Holt, Et Al
Comparison Of Plankton Catch By Three Light-Trap Designs In The Northern Gulf Of Mexico, Richard F. Shaw, Joseph S. Cope, G. Joan Holt, Et Al
VIMS Articles
The ichthyoplankton catch and zooplankton biomass estimates of three light-trap designs-cylindrical, quatrefoil, and rectangular-were compared over three consecutive nights at an offshore petroleum platform in the northern Gulf of Mexico. The quatrefoil light trap had higher fish and zooplankton abundance estimates than the other two designs. Categorical analysis of the two abundant fish taxa, Opisthonema oglinum and Anchoa spp., indicated that catch by the quatrefoil and rectangular traps was similar, capturing more larvae than juveniles and more O. oglinum than Anchoa spp. relative to cylindrical trap catch. Across all fish species, the quatrefoil captured a greater percentage of larvae. Other …
Barnegat Bay-Little Egg Harbor Estuary: Case Study Of A Highly Eutrophic Coastal Bay System, Mj Kennish, Sb Bricker, Wc Dennison, Pm Glibert, Rj Livingston, Ken Moore, Et Al.
Barnegat Bay-Little Egg Harbor Estuary: Case Study Of A Highly Eutrophic Coastal Bay System, Mj Kennish, Sb Bricker, Wc Dennison, Pm Glibert, Rj Livingston, Ken Moore, Et Al.
VIMS Articles
The Barnegat Bay-Little Egg Harbor Estuary is classified here as a highly eutrophic estuary based on application of the National Oceanic and Atmospheric Administration's National Estuarine Eutrophication Assessment model. Because it is shallow, poorly flushed, and bordered by highly developed watershed areas, the estuary is particularly susceptible to the effects of nutrient loading. Most of this load (similar to 50%) is from surface water inflow, but substantial fractions also originate from atmospheric deposition (similar to 39%), and direct groundwater discharges (similar to 11%). No point source inputs of nutrients exist in the Barnegat Bay watershed. Since 1980, all treated wastewater …
Influence Of Sea Ice Cover And Icebergs On Circulation And Water Mass Formation In A Numerical Circulation Model Of The Ross Sea, Antarctica, Michael S. Dinniman, John M. Klinck, Walker O. Smith Jr.
Influence Of Sea Ice Cover And Icebergs On Circulation And Water Mass Formation In A Numerical Circulation Model Of The Ross Sea, Antarctica, Michael S. Dinniman, John M. Klinck, Walker O. Smith Jr.
VIMS Articles
Satellite imagery shows that there was substantial variability in the sea ice extent in the Ross Sea during 2001-2003. Much of this variability is thought to be due to several large icebergs that moved through the area during that period. The effects of these changes in sea ice on circulation and water mass distributions are investigated with a numerical general circulation model. It would be difficult to simulate the highly variable sea ice from 2001 to 2003 with a dynamic sea ice model since much of the variability was due to the floating icebergs. Here, sea ice concentration is specified …
Nutrient Versus Consumer Control Of Community Structure In A Chesapeake Bay Eelgrass Habitat, James Grayland Douglass, J. Emmett Duffy, Amanda C. Spivak, John Paul Richardson
Nutrient Versus Consumer Control Of Community Structure In A Chesapeake Bay Eelgrass Habitat, James Grayland Douglass, J. Emmett Duffy, Amanda C. Spivak, John Paul Richardson
VIMS Articles
Nutrient loading can dramatically alter benthic communities and has been implicated in the worldwide decline of seagrass beds. Ongoing changes in food webs caused by overfishing could also contribute to seagrass decline. However, the interaction of these factors and the role of small invertebrate grazers in mediating them are poorly understood. We examined the relative impacts of nutrient loading and food web alteration on eelgrass Zostera marina L. community structure in Chesapeake Bay by manipulating nutrients, predatory crabs, and invertebrate grazers in field enclosures over 28 d in summer. Nutrient loading increased epiphyte accumulation early in the experiment, decreased eelgrass …
Linking Water Quality To Living Resources In A Mid-Atlantic Lagoon System, Usa, Ce Wazniak, Mr Hall, Tjb Carruthers, B Sturgis, Wc Dennison, Rj Orth
Linking Water Quality To Living Resources In A Mid-Atlantic Lagoon System, Usa, Ce Wazniak, Mr Hall, Tjb Carruthers, B Sturgis, Wc Dennison, Rj Orth
VIMS Articles
The mid-Atlantic coastal bays are shallow coastal lagoons, separated from the Atlantic Ocean by barrier sand islands with oceanic exchanges restricted to narrow inlets. The relatively poor flushing of these lagoon systems makes them susceptible to eutrophication resulting from anthropogenic nutrient loadings. An intensive water quality and seagrass monitoring program was initiated to track ecological changes in the Maryland and Virginia coastal bays. The purpose of this study was to analyze existing monitoring data to determine status and trends in eutrophication and to determine any associations between water quality and living resources. Analysis of monitoring program data revealed several trends: …
Comparison Of Cell-Specific Activity Between Free-Living And Attached Bacteria Using Isolates And Natural Assemblages, Hp Gropssar, Kw Tang, T Kiorboe, H Ploug
Comparison Of Cell-Specific Activity Between Free-Living And Attached Bacteria Using Isolates And Natural Assemblages, Hp Gropssar, Kw Tang, T Kiorboe, H Ploug
VIMS Articles
Marine snow aggregates are microbial hotspots that support high bacterial abundance and activities. We conducted laboratory experiments to compare cell-specific bacterial protein production (BPP) and protease activity between free-living and attached bacteria. Natural bacterial assemblages attached to model aggregates (agar spheres) had threefold higher BPP and two orders of magnitude higher protease activity than their free-living counterpart. These observations could be explained by preferential colonization of the agar spheres by bacteria with inherently higher metabolic activity and/or individual bacteria increasing their metabolism upon attachment to surfaces. In subsequent experiments, we used four strains of marine snow bacteria isolates to test …
Phytoplankton Blooms In The Ross Sea, Antarctica: Interannual Variability In Magnitude, Temporal Patterns, And Composition, Jill A. Peloquin, Walker O. Smith Jr.
Phytoplankton Blooms In The Ross Sea, Antarctica: Interannual Variability In Magnitude, Temporal Patterns, And Composition, Jill A. Peloquin, Walker O. Smith Jr.
VIMS Articles
The continental shelf of the Ross Sea, Antarctica, is a unique region within the Southern Ocean. Phytoplankton growth is believed to be seasonally limited, first in austral spring by irradiance, and then in summer by biologically available iron. It also is historically known to have taxonomically distinct regimes: the south-central portion is dominated by Phaeocystis antarctica and to the west diatoms are abundant. We measured photochemical yield to interpret the health of the phytoplankton assemblage from 2001-2004 and interfaced these measurements with satellite remote sensing of pigments. The bloom of 2001-2002 was similar in both temporal and spatial distributions to …