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Regional Differences In Quality Of Krill And Fish As Prey Along The Western Antarctic Peninsula, Kate E. Ruck, Deborah K. Steinberg, Elizabeth A. Canuel
Regional Differences In Quality Of Krill And Fish As Prey Along The Western Antarctic Peninsula, Kate E. Ruck, Deborah K. Steinberg, Elizabeth A. Canuel
VIMS Articles
The warming trend in the northern part of the Western Antarctic Peninsula (WAP) has led to a decrease in perennial and summer sea ice, an increase in heat content over the shelf, and lower phytoplankton biomass, which could affect the prey quality of krill and fish that are utilized by apex predators. We compared prey quality metrics, including elemental (C, N) content; total, neutral, and polar lipid content; and energy densities of known penguin prey items including krill (Euphausia superba, Thysanoessa macrura, and E. crystallorophias) and fish (silverfish Pleuragramma antarcticum and the myctophid Electrona antarctica) …
Shell Condition And Survival Of Puget Sound Pteropods Are Impaired By Ocean Acidification Conditions, D. Shallin Busch, Michael Maher, Patricia Thibodeau, Paul Mcelhany
Shell Condition And Survival Of Puget Sound Pteropods Are Impaired By Ocean Acidification Conditions, D. Shallin Busch, Michael Maher, Patricia Thibodeau, Paul Mcelhany
VIMS Articles
We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Ωa) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (∼460–500 µatm CO2, Ωa≈1.59), current deep water or surface conditions during upwelling (∼760 and ∼1600–1700 µatm CO2, Ωa≈1.17 …
Use Of Neutral Red In Short-Term Sediment Traps To Distinguish Between Zooplankton Swimmers And Carcasses, Jami Ivory, Kam Tang, Kazutaka Takahasi
Use Of Neutral Red In Short-Term Sediment Traps To Distinguish Between Zooplankton Swimmers And Carcasses, Jami Ivory, Kam Tang, Kazutaka Takahasi
VIMS Articles
The presence of zooplankton swimmers and carcasses in sediment trap samples has long been a concern in particle flux studies. We successfully developed a protocol using the vital stain Neutral Red to distinguish between copepod swimmers and carcasses in conventional cylindrical sediment traps. Swimmers were stained red whereas carcasses were pale or unstained.The color distinction allowed easy quantification of the two. We subsequently used the protocol in Otsuchi Bay, Japan, on 4 consecutive days in May and again in July 2013. Carcasses were presentin the sediment traps on all occasions, and calanoid and cyclopoid copepods accounted for 60.0−93.6% of all …
Structure And Function Of Zooplankton-Associated Bacterial Communities In A Temperate Estuary Change More With Time Than With Zooplankton Species, Samatha L. Bickel, Kam W. Tang, Hans-Peter Grossart
Structure And Function Of Zooplankton-Associated Bacterial Communities In A Temperate Estuary Change More With Time Than With Zooplankton Species, Samatha L. Bickel, Kam W. Tang, Hans-Peter Grossart
VIMS Articles
Zooplankton support distinct bacterial communities in high concentrations relative to the surrounding water, but little is known about how the compositions and functionalities of these bacterial communities change through time in relation to environmental conditions. We conducted a year-long field study of bacterial communities associated with common zooplankton groups as well as free-living bacterial communities in the York River, a tributary of Chesapeake Bay. Bacterial community genetic fingerprints and their carbon substrate usage were examined by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA and by Biolog EcoPlates, respectively. Zooplankton-associated communities were genetically distinct from free-living bacterial communities but …
Investigating The Relationship Between Biodiversity And Ecosystem Multifunctionality: Challenges And Solutions, Jarrett E. K. Byrnes, Lars Gamfeldt, Forest Isbell, Jonathan S. Lefcheck, John N. Griffin, Andy Hector, Bradley J. Cardinale, David U. Hooper, Laura E. Dee, J. Emmett Duffy
Investigating The Relationship Between Biodiversity And Ecosystem Multifunctionality: Challenges And Solutions, Jarrett E. K. Byrnes, Lars Gamfeldt, Forest Isbell, Jonathan S. Lefcheck, John N. Griffin, Andy Hector, Bradley J. Cardinale, David U. Hooper, Laura E. Dee, J. Emmett Duffy
VIMS Articles
Summary 1. Extensive research shows that more species-rich assemblages are generally more productive and efficient in resource use than comparable assemblages with fewer species. But the question of how diversity simultaneously affects the wide variety of ecological functions that ecosystems perform remains relatively understudied. It presents several analytical and empirical challenges that remain unresolved. In particular, researchers have developed several disparate metrics to quantify multifunctionality, each characterizing different aspects of the concept and each with pros and cons. 2. We compare four approaches to characterizing multifunctionality and its dependence on biodiversity, quantifying (i) magnitudes of multiple individual functions separately, (ii) …
Biogeochemical Variability In The Southern Ross Sea As Observed By A Glider Deployment, De Kaufman, Mam Friedrichs, Wj Smith Jr., By Queste, Kj Heywood
Biogeochemical Variability In The Southern Ross Sea As Observed By A Glider Deployment, De Kaufman, Mam Friedrichs, Wj Smith Jr., By Queste, Kj Heywood
VIMS Articles
High-resolution autonomous glider data (including temperature, salinity, fluorescence, and optical backscatter) collected during the 2010-2011 austral summer identified variations in phytoplankton biomass along two glider sections near 76 degrees 40'S. Sea surface temperatures were warmer during the latter, westward section, while mixed layer depths were deeper. Substantial quantities of Modified Circumpolar Deep Water, identified by neutral density criteria, were located within both sections. Chlorophyll (Chl) concentrations computed from fluorescence exhibited daily quenching near the surface, and deep chlorophyll concentrations at 200 m became periodically elevated, suggesting substantial export on small space and time scales. The concentrations of particulate organic carbon …
Dimensions Of Biodiversity In Chesapeake Bay Demersal Fishes: Patterns And Drivers Through Space And Time, Jonathan S. Lefcheck, Andre Buchheister, Katie May Laumann, Mark A. Stratton, Kathryn L. Sobocinski, Soloman Chak, Todd R. Clardy, Pamela L. Reynolds, Robert J. Latour, Emmett J. Duffy
Dimensions Of Biodiversity In Chesapeake Bay Demersal Fishes: Patterns And Drivers Through Space And Time, Jonathan S. Lefcheck, Andre Buchheister, Katie May Laumann, Mark A. Stratton, Kathryn L. Sobocinski, Soloman Chak, Todd R. Clardy, Pamela L. Reynolds, Robert J. Latour, Emmett J. Duffy
VIMS Articles
Biodiversity has typically been described in terms of species richness and composition, but theory and growing empirical evidence indicate that the diversity of functional traits, the breadth of evolutionary relationships, and the equitability with which individuals or biomass are distributed among species better characterize patterns and processes within ecosystems. Yet, the advantages of including such data come at the expense of measuring traits, sequencing genes, and counting or weighing individuals, and it remains unclear whether this greater resolution yields substantial benefits in describing diversity. We summarized a decade of high-resolution trawl data from a bimonthly trawl survey to investigate spatial …
Impacts Of Freshwater Flushing On Anammox Community Structure And Activities In The New River Estuary, Usa, Ja Lisa, B Song, Cr Tobias, Ka Duernberger
Impacts Of Freshwater Flushing On Anammox Community Structure And Activities In The New River Estuary, Usa, Ja Lisa, B Song, Cr Tobias, Ka Duernberger
VIMS Articles
Anaerobic ammonium oxidation (anammox) and denitrification are 2 microbial nitrogen removal processes that may play an important role in controlling the intensity and duration of estuarine and coastal eutrophication. Sediment communities in the New River Estuary, North Carolina were investigated to determine the dynamics of anammox activity and community structure in conjunction with environmental conditions. N-15 tracer incubation experiments with sediment slurries were used to measure anammox and denitrification rates and estimate anammox contribution to total N-2 production. Molecular analyses targeting the hydrazine oxidoreductase (hzo) gene were conducted to examine the structure of anammox communities and quantify the abundance of …
Field Experimental Evidence That Grazers Mediate Transition Between Microalgal And Seagrass Dominance, Pl Reynolds, Jp Richardson, Je Duffy
Field Experimental Evidence That Grazers Mediate Transition Between Microalgal And Seagrass Dominance, Pl Reynolds, Jp Richardson, Je Duffy
VIMS Articles
We tested the relative effects of nutrient loading, reduced predation, and reduced grazing on eelgrass community dynamics in Chesapeake Bay and found evidence supporting the "mutualistic mesograzer model" in which small invertebrate grazers control accumulation of epiphytic algae, buffer eutrophication effects, and thus facilitate seagrass dominance. Experimental reduction of crustacean grazers in the field stimulated a nearly sixfold increase in epiphytic algae, and reduced seagrass biomass by 65% compared to controls with grazers. Nutrient fertilization generally had much weaker effects, but an interaction with mesograzers was key in changing the sign of fertilization effects on the system: aboveground eelgrass biomass …
Winter And Spring Controls On The Summer Food Web Of The Coastal West Antarctic Peninsula, Grace K. Saba, William R. Fraser, Vincent S. Saba, Richard A. Iannuzzi, Kaycee E. Coleman, Scott C. Doney, Hugh W. Ducklow, Douglas G. Martinson, Travis N. Miles, Donna L. Patterson-Fraser, Sharon E. Stammerjohn, Deborah K. Steinberg
Winter And Spring Controls On The Summer Food Web Of The Coastal West Antarctic Peninsula, Grace K. Saba, William R. Fraser, Vincent S. Saba, Richard A. Iannuzzi, Kaycee E. Coleman, Scott C. Doney, Hugh W. Ducklow, Douglas G. Martinson, Travis N. Miles, Donna L. Patterson-Fraser, Sharon E. Stammerjohn, Deborah K. Steinberg
VIMS Articles
Understanding the mechanisms by which climate variability affects multiple trophic levels in food webs is essential for determining ecosystem responses to climate change. Here we use over two decades of data collected by the Palmer Long Term Ecological Research program (PAL-LTER) to determine how large-scale climate and local physical forcing affect phytoplankton, zooplankton and an apex predator along the West Antarctic Peninsula (WAP). We show that positive anomalies in chlorophyll-a (chl-a) at Palmer Station, occurring every 4-6 years, are constrained by physical processes in the preceding winter/spring and a negative phase of the Southern Annular Mode (SAM). Favorable conditions for …
Individual, Population, And Ecosystem Effects Of Hypoxia On A Dominant Benthic Bivalve In Chesapeake Bay, W. Christopher Long, Rochelle D. Seitz, Bryce J. Brylawski, Romuald N. Lipcius
Individual, Population, And Ecosystem Effects Of Hypoxia On A Dominant Benthic Bivalve In Chesapeake Bay, W. Christopher Long, Rochelle D. Seitz, Bryce J. Brylawski, Romuald N. Lipcius
VIMS Articles
Hypoxia is an environmental stressor that affects abundance, biomass,diversity, and ecosystem function of benthic assemblages worldwide, yet its collective impact at individual, population, and ecosystem levels has rarely been investigated. We examined the effects of hypoxia on the biomass-dominant clam,Macoma balthica, in the York and Rappahannock Rivers (Chesapeake Bay, USA). We (1) surveyed the M. balthica populationsin both rivers in 2003 and 2004, (2) determined the effects of low dissolved oxygen (DO) on M.balthica fecundity in a laboratory experiment, and (3) employed a predator-exclusion fieldexperiment to establish the effects of hypoxia and prey density on predation upon M. balthica.The resultant …
Long-Term Time-Series Study Of Salp Population Dynamics In The Sargasso Sea, Joshua P. Stone, Deborah K. Steinberg
Long-Term Time-Series Study Of Salp Population Dynamics In The Sargasso Sea, Joshua P. Stone, Deborah K. Steinberg
VIMS Articles
Salps are bloom-forming, pelagic tunicates with high grazing rates on phytoplankton, with the potential to greatly increase vertical particle flux through rapidly sinking fecal pellets. However, the frequency and causes of salp blooms are not well known. We quantified salps from day and night zooplankton net tows in the epipelagic zone of the North Atlantic subtropical gyre as part of the Bermuda Atlantic Time-series Study (BATS). Salp species and size were quantified in biweekly to monthly tows from April 1994 to November 2011. Twenty-one species of salps occurred at the BATS site over this time period, and the most common …
Linking Dnra Community Structure And Activity In A Shallow Lagoonal Estuarine System, Bongkeun Song, Jessica A. Lisa, Craig R. Tobias
Linking Dnra Community Structure And Activity In A Shallow Lagoonal Estuarine System, Bongkeun Song, Jessica A. Lisa, Craig R. Tobias
VIMS Articles
Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are two nitrate respiration pathways in the microbial nitrogen cycle. Diversity and abundance of denitrifying bacteria have been extensively examined in various ecosystems. However, studies on DNRA bacterial diversity are limited, and the linkage between the structure and activity of DNRA communities has yet to be discovered. We examined the composition, diversity, abundance, and activities of DNRA communities at five sites along a salinity gradient in the New River Estuary, North Carolina, USA, a shallow temporal/lagoonal estuarine system. Sediment slurry incubation experiments with N-15-nitrate were conducted to measure potential DNRA rates, while …
The Assimilation Of Satellite-Derived Data Into A One-Dimensional Lower Trophic Level Marine Ecosystem Model, Yongjin Xiao, Marjorie A.M. Friedrichs
The Assimilation Of Satellite-Derived Data Into A One-Dimensional Lower Trophic Level Marine Ecosystem Model, Yongjin Xiao, Marjorie A.M. Friedrichs
VIMS Articles
Lower trophic level marine ecosystem models are highly dependent on the parameter values given to key rate processes, however many of these are either unknown or difficult to measure. One solution to this problem is to apply data assimilation techniques that optimize key parameter values, however in many cases in situ ecosystem data are unavailable on the temporal and spatial scales of interest. Although multiple types of satellite-derived data are now available with high temporal and spatial resolution, the relative advantages of assimilating different satellite data types are not well known. Here these issues are examined by implementing a lower …
Using Biogeochemical Data Assimilation To Assess The Relative Skill Of Multiple Ecosystem Models In The Mid-Atlantic Bight: Effects Of Increasing The Complexity Of The Planktonic Food Web, Y. Xiao, Marjorie A.M. Friedrichs
Using Biogeochemical Data Assimilation To Assess The Relative Skill Of Multiple Ecosystem Models In The Mid-Atlantic Bight: Effects Of Increasing The Complexity Of The Planktonic Food Web, Y. Xiao, Marjorie A.M. Friedrichs
VIMS Articles
Now that regional circulation patterns can be reasonably well reproduced by ocean circulation models, significant effort is being directed toward incorporating complex food webs into these models, many of which now routinely include multiple phytoplankton (P) and zooplankton (Z) compartments. This study quantitatively assesses how the number of phytoplankton and zooplankton compartments affects the ability of a lower-trophic-level ecosystem model to reproduce and predict observed patterns in surface chlorophyll and particulate organic carbon. Five ecosystem model variants are implemented in a one-dimensional assimilative (variational adjoint) model testbed in the Mid-Atlantic Bight. The five models are identical except for variations in …
Multifunctionality Does Not Imply That All Functions Are Positively Correlated, J Byrnes, Js Lefcheck, L Gamfeldt, Jn Griffin, F Isbell
Multifunctionality Does Not Imply That All Functions Are Positively Correlated, J Byrnes, Js Lefcheck, L Gamfeldt, Jn Griffin, F Isbell
VIMS Articles
No abstract provided.
Value Of Coastal Habitats For Exploited Species: Introduction To A Theme Set Of Articles, Rochelle D. Seitz
Value Of Coastal Habitats For Exploited Species: Introduction To A Theme Set Of Articles, Rochelle D. Seitz
VIMS Articles
Many exploited fish and invertebrate species use coastal habitats during one or more life-history stages as spawning, feeding, and nursery areas; yet, the value of these habitats has not been adequately characterized. As habitat availability can be a bottleneck for many populations, concerns about habitat effects on exploited species have been increasing. We have compiled nine articles presenting the state of knowledge and future research priorities regarding the importance of habitat for exploited species. Reviews from European habitats and several geographical locations throughout the United States demonstrate the influence of coastal habitats on survival, growth, and movement, especially during the …
Zooplankton Carcasses And Non-Predatory Mortality In Freshwater And Inland Sea Environments, Kw Tang, Mi Gladyshev, Op Dubovskaya, G Kirillin, Hp Grossart
Zooplankton Carcasses And Non-Predatory Mortality In Freshwater And Inland Sea Environments, Kw Tang, Mi Gladyshev, Op Dubovskaya, G Kirillin, Hp Grossart
VIMS Articles
Zooplankton carcasses are ubiquitous in marine and freshwater systems, implicating the importance of non-predatory mortality, but both are often overlooked in ecological studies compared with predatory mortality. The development of several microscopic methods allows the distinction between live and dead zooplankton in field samples, and the reported percentages of dead zooplankton average 11.6 (minimum) to 59.8 (maximum) in marine environments, and 7.4 (minimum) to 47.6 (maximum) in fresh and inland waters. Common causes of non-predatory mortality among zooplankton include senescence, temperature change, physical and chemical stresses, parasitism and food-related factors. Carcasses resulting from non-predatory mortality may undergo decomposition leading to …
Ecological Value Of Coastal Habitats For Commercially And Ecologically Important Species, Rochelle D. Seitz, H Wennhage, U Bergstrom, Rn Lipcius, T Ysebaert
Ecological Value Of Coastal Habitats For Commercially And Ecologically Important Species, Rochelle D. Seitz, H Wennhage, U Bergstrom, Rn Lipcius, T Ysebaert
VIMS Articles
Many exploited fish and macroinvertebrates that utilize the coastal zone have declined, and the causes of these declines, apart from overfishing, remain largely unresolved. Degradation of essential habitats has resulted in habitats that are no longer adequate to fulfil nursery, feeding, or reproductive functions, yet the degree to which coastal habitats are important for exploited species has not been quantified. Thus, we reviewed and synthesized literature on the ecological value of coastal habitats (i.e. seagrass beds, shallow subtidal and intertidal habitats, kelp beds, shallow open water habitats, saltmarshes, mussel beds, macroalgal beds, rocky bottom, and mariculture beds) as feeding grounds, …
Paradox Reconsidered: Methane Oversaturation In Well-Oxygenated Lake Waters, Kw Tang, Df Mcginnis, K Frindte, V Bruchert, Hp Grossart
Paradox Reconsidered: Methane Oversaturation In Well-Oxygenated Lake Waters, Kw Tang, Df Mcginnis, K Frindte, V Bruchert, Hp Grossart
VIMS Articles
The widely reported paradox of methane oversaturation in oxygenated water challenges the prevailing paradigm that microbial methanogenesis only occurs under anoxic conditions. Using a combination of field sampling, incubation experiments, and modeling, we show that the recurring mid-water methane peak in Lake Stechlin, northeast Germany, was not dependent on methane input from the littoral zone or bottom sediment or on the presence of known micro-anoxic zones. The methane peak repeatedly overlapped with oxygen oversaturation in the seasonal thermocline. Incubation experiments and isotope analysis indicated active methane production, which was likely linked to photosynthesis and/or nitrogen fixation within the oxygenated water, …