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Full-Text Articles in Life Sciences

Fish Assemblage Change Following The Structural Restoration Of A Degraded Stream, Carl A. Favata, Anabela Maia, Manisha Pant, Vaskar Nepal Oct 2018

Fish Assemblage Change Following The Structural Restoration Of A Degraded Stream, Carl A. Favata, Anabela Maia, Manisha Pant, Vaskar Nepal

VIMS Articles

Decades of anthropogenic pressure have harmed riverscapes throughout North America by degrading habitats and water quality and can result in the extirpation of sensitive aquatic taxa. Local stream restoration projects have increased in frequency, but monitoring is still infrequent. In 2010, Kickapoo Creek in East Central Illinois was subjected to a stream restoration project that included implementation of artificial riffles, riprap, scouring keys, and riparian vegetation. We monitored the restoration efforts for 6years after the restoration through annual sampling efforts at restored and reference sites to determine changes in habitat and fish assemblage using standard habitat sampling and electrofishing techniques ...


Differential Effects Of Bivalves On Sediment Nitrogen Cycling In A Shallow Coastal Bay, Ashley Smyth, Anna E. Murphy, Iris C. Anderson, Bk Song Jan 2017

Differential Effects Of Bivalves On Sediment Nitrogen Cycling In A Shallow Coastal Bay, Ashley Smyth, Anna E. Murphy, Iris C. Anderson, Bk Song

VIMS Articles

In coastal ecosystems, suspension-feeding bivalves can remove nitrogen though uptake and assimilation or enhanced denitrification. Bivalves may also retain nitrogen through increased mineralization and dissimilatory nitrate reduction to ammonium (DNRA). This study investigated the effects of oyster reefs and clam aquaculture on denitrification, DNRA, and nutrient fluxes (NOx, NH4 6 +, O2). Core incubations were conducted seasonally on sediments adjacent to restored oyster reefs (Crassostrea virginica), clam aquaculture beds (Mercenaria mercenaria) which contained live clams, and bare sediments from Smith Island Bay, Virginia, USA. Denitrification was significantly higher at oyster reef sediments and clam aquaculture site than bare sediment in the ...


Effects Of Terrestrial–Aquatic Connectivity On An Estuarine Turtle, Robert E. Isdell, Randolph M. Chambers, Donna M. Bilkovic, Matthias Leu Jan 2015

Effects Of Terrestrial–Aquatic Connectivity On An Estuarine Turtle, Robert E. Isdell, Randolph M. Chambers, Donna M. Bilkovic, Matthias Leu

VIMS Articles

Estuaries world-wide have been modified or fragmented due to human stressors in their terrestrial and aquatic components. Estuary fragmentation often results in reductions in species richness, diversity and connectivity. Effects of human modification on estuaries have been well studied, but less is known about how land use alters connectivity of the terrestrial–aquatic ecotone. We studied the relationship between terrestrial–aquatic connectivity and the distri- bution of an estuarine turtle, diamondback terrapin (Malaclemys terrapin).


Global Patterns In The Impact Of Marine Herbivores On Benthic Primary Producers, Alistair G.B. Poore, Alexandra H. Campbell, Ross Coleman, Graham J. Edgar, Veijo Jormalainen, Pamela L. Reynolds, Erik E. Sotka, John J. Stachowicz, Richard Taylor, Mathew A. Vanderklift, J. Emmett Duffy May 2012

Global Patterns In The Impact Of Marine Herbivores On Benthic Primary Producers, Alistair G.B. Poore, Alexandra H. Campbell, Ross Coleman, Graham J. Edgar, Veijo Jormalainen, Pamela L. Reynolds, Erik E. Sotka, John J. Stachowicz, Richard Taylor, Mathew A. Vanderklift, J. Emmett Duffy

VIMS Articles

Despite the importance of consumers in structuring communities, and the widespread assumption that consumption is strongest at low latitudes, empirical tests for global scale patterns in the magnitude of consumer impacts are limited. In marine systems, the long tradition of experimentally excluding herbivores in their natural environments allows consumer impacts to be quantified on global scales using consistent methodology. We present a quantitative synthesis of 613 marine herbivore exclusion experiments to test the influence of consumer traits, producer traits and the environment on the strength of herbivore impacts on benthic producers. Across the globe, marine herbivores profoundly reduced producer abundance ...


The Functional Role Of Producer Diversity In Ecosystems, Bradley J. Cardinale, Kristin L. Matulich, David U. Hooper, Jarrett E. K. Byrnes, Emmett J. Duffy, Lars Gamfeldt, Patricia Balvanera, Mary I. O'Connor, Andrew Gonzalez Mar 2011

The Functional Role Of Producer Diversity In Ecosystems, Bradley J. Cardinale, Kristin L. Matulich, David U. Hooper, Jarrett E. K. Byrnes, Emmett J. Duffy, Lars Gamfeldt, Patricia Balvanera, Mary I. O'Connor, Andrew Gonzalez

VIMS Articles

Over the past several decades, a rapidly expanding field of research known as biodiversity and ecosystem functioning has begun to quantify how the world's biological diversity can, as an independent variable, control ecological processes that are both essential for, and fundamental to, the functioning of ecosystems. Research in this area has often been justified on grounds that (1) loss of biological diversity ranks among the most pronounced changes to the global environment and that (2) reductions in diversity, and corresponding changes in species composition, could alter important services that ecosystems provide to humanity (e.g., food production, pest/disease ...


Oyster Reefs At Risk And Recommendations For Conservation, Restoration, And Management, Michael W. Beck, Robert D. Brumbaugh, Laura Airoldi, Alvar Carranza, Loren D. Coen, Christine Crawford, Omar Defeo, Graham J. Edgar, Boze Handcock, Matthew C. Kay, Hunter S. Lenihan, Mark Luckenbach, Caitlyn L. Toropova, Guofan Zhang, Ximing Guo Feb 2011

Oyster Reefs At Risk And Recommendations For Conservation, Restoration, And Management, Michael W. Beck, Robert D. Brumbaugh, Laura Airoldi, Alvar Carranza, Loren D. Coen, Christine Crawford, Omar Defeo, Graham J. Edgar, Boze Handcock, Matthew C. Kay, Hunter S. Lenihan, Mark Luckenbach, Caitlyn L. Toropova, Guofan Zhang, Ximing Guo

VIMS Articles

Native oyster reefs once dominated many estuaries, ecologically and economically. Centuries of resource extraction exacerbated by coastal degradation have pushed oyster reefs to the brink of functional extinction worldwide. We examined the condition of oyster reefs across 144 bays and 44 ecoregions; our comparisons of past with present abundances indicate that more than 90% of them have been lost in bays (70%) and ecoregions (63%). In many bays, more than 99% of oyster reefs have been lost and are functionally extinct. Overall, we estimate that 85% of oyster reefs have been lost globally. Most of the world's remaining wild ...


Accelerating Loss Of Seagrasses Across The Globe Threatens Coastal Ecosystems, Michelle Waycott, Carlos M. Duarte, Tim J. Carruthers, Robert J. Orth, Wc Dennison, Suzanne Olyarnik, Ainsley Calladine, James W. Fourqurean, Kl Heck, A. Randall Hughes, Gary A. Kendrick, W. Judson Kenworthy, Frederick T. Short, Susan L. Williams May 2009

Accelerating Loss Of Seagrasses Across The Globe Threatens Coastal Ecosystems, Michelle Waycott, Carlos M. Duarte, Tim J. Carruthers, Robert J. Orth, Wc Dennison, Suzanne Olyarnik, Ainsley Calladine, James W. Fourqurean, Kl Heck, A. Randall Hughes, Gary A. Kendrick, W. Judson Kenworthy, Frederick T. Short, Susan L. Williams

VIMS Articles

Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling; an order of magnitude enhancement of coral reef fish productivity; a habitat for thousands of fish, bird, and invertebrate species; and a major food source for endangered dugong, manatee, and green turtle. Although individual impacts from coastal development, degraded water ...


Bacterial Vs. Zooplankton Control Of Sinking Particle Flux In The Ocean's Twilight Zone, Deborah K. Steinberg, Benjamin A.S. Van Mooy, Ken O. Buesseler, Philip W. Boyd, Toru Kobari, David M. Karl Jul 2008

Bacterial Vs. Zooplankton Control Of Sinking Particle Flux In The Ocean's Twilight Zone, Deborah K. Steinberg, Benjamin A.S. Van Mooy, Ken O. Buesseler, Philip W. Boyd, Toru Kobari, David M. Karl

VIMS Articles

The downward flux of particulate organic carbon (POC) decreases significantly in the oceanÂs mesopelagic or ‘twilight’ zone due both to abiotic processes and metabolism by resident biota. Bacteria and zooplankton solubilize and consume POC to support their metabolism, but the relative importance of bacteria vs. zooplankton in the consumption of sinking particles in the twilight zone is unknown. We compared losses of sinking POC, using differences in export flux measured by neutrally buoyant sediment traps at a range of depths, with bacteria and zooplankton metabolic requirements at the Hawaii Ocean Time‐series station ALOHA in the subtropical Pacific and the ...


The Charisma Of Coastal Ecosystems: Addressing The Imbalance, Carlos M. Duarte, Wc Dennison, Robert J. Orth, Tim J. Carruthers Feb 2008

The Charisma Of Coastal Ecosystems: Addressing The Imbalance, Carlos M. Duarte, Wc Dennison, Robert J. Orth, Tim J. Carruthers

VIMS Articles

Coastal ecosystems including coral reefs, mangrove forests, seagrass meadows, and salt marshes are being lost at alarming rates, and increased scientific understanding of causes has failed to stem these losses. Coastal habitats receive contrasting research effort, with 60% of all of the published research carried out on coral reefs, compared to 11–14% of the records for each of salt marshes, mangrove forests, and seagrass meadows. In addition, these highly connected and interdependent coastal ecosystems receive widely contrasting media attention that is disproportional to their scientific attention. Seagrass ecosystems receive the least attention in the media (1.3% of the ...


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 Apr 2007

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 ...


Evaluation Of A Lifetime‐Based Optode To Measure Oxygen In Aquatic Systems, Anders Tengberg, Jostein Hovdenes, Henrik J. Andersson, Olivier Brocandel, Robert J. Diaz, David Hebert, Tony Arnerich, Christian Huber, Arne Kortzinger, Alexis Khripounoff, Francisco Rey, Christer Ronning, Jens Schimanski, Stefan Sommer, Achim Stangelmayer Feb 2006

Evaluation Of A Lifetime‐Based Optode To Measure Oxygen In Aquatic Systems, Anders Tengberg, Jostein Hovdenes, Henrik J. Andersson, Olivier Brocandel, Robert J. Diaz, David Hebert, Tony Arnerich, Christian Huber, Arne Kortzinger, Alexis Khripounoff, Francisco Rey, Christer Ronning, Jens Schimanski, Stefan Sommer, Achim Stangelmayer

VIMS Articles

In this article, we evaluate the performance of a commercially available lifetime‐based optode and compare it with data obtained by other methods. We performed a set of 10 different tests, including targeted laboratory evaluations and field studies, covering a wide range of situations from shallow coastal waters and wastewater treatment plants to abyssal depths. Our principal conclusion is that, owing to high accuracy (± 2 µM), long‐term stability (more than 20 months), lack of pressure hysteresis, and limited cross‐sensitivity, this method is overall more suitable for oxygen monitoring than other methods.


Allee Effects Driven By Predation, J Gascoigne, Rom Lipcius Sep 2004

Allee Effects Driven By Predation, J Gascoigne, Rom Lipcius

VIMS Articles

No abstract provided.


Abundance And Distribution Of Planktonic Archaea And Bacteria In The Waters West Of The Antarctic Peninsula, Matthew Church, Edward F. Delong, Hugh Ducklow, Markus Karner, Christian Preston, David M. Karl Sep 2003

Abundance And Distribution Of Planktonic Archaea And Bacteria In The Waters West Of The Antarctic Peninsula, Matthew Church, Edward F. Delong, Hugh Ducklow, Markus Karner, Christian Preston, David M. Karl

VIMS Articles

Polyribonucleotide probes targeting planktonic archaeal (Group I and II) and bacterial rRNA revealed that Archaea comprised a significant fraction of total prokaryote cell abundance in the marine waters west of the Antarctic Peninsula. Determinations of Archaea and Bacteria cell abundances were made during two research cruises to the Palmer Long‐Term Ecological Research region during the austral winter and summer of 1999. During the austral summer, surface water abundances of Group I (GI) Archaea were generally low, averaging 4.7 x 103 cells ml−1 and accounting for 1% of the total picoplankton assemblage. The abundance of GI Archaea increased ...


Biodiversity And Ecosystem Function: The Consumer Connection, J. Emmett Duffy Dec 2002

Biodiversity And Ecosystem Function: The Consumer Connection, J. Emmett Duffy

VIMS Articles

Proposed links between biodiversity and ecosystem processes have generated intense interest and controversy in recent years. With few exceptions, however, empirical studies have focused on grassland plants and laboratory aquatic microbial systems, whereas there has been little attention to how changing animal diversity may influence ecosystem processes. Meanwhile, a separate research tradition has demonstrated strong top‐down forcing in many systems, but has considered the role of diversity in these processes only tangentially. Integration of these research directions is necessary for more complete understanding in both areas. Several considerations suggest that changing diversity in multi‐level food webs can have ...


Relative Strengths Of Competition For Space And Food In A Sessile Filter Feeder, David P. Lohse Oct 2002

Relative Strengths Of Competition For Space And Food In A Sessile Filter Feeder, David P. Lohse

VIMS Articles

Previous workers have demonstrated that sessile filter feeders compete for food and space, but little is known about the relative strengths of these two processes. To determine this, the density and position of barnacles (Balanus improvisus) in a unidirectional current were manipulated to alter the amount of competition for space and food, respectively. Results indicated that competition for space significantly reduced growth, and marginally reduced survivorship. Competition for food was also detected, but only among uncrowded individuals; thus, it appears to be the weaker of the two interactions. However, under crowded conditions, downstream individuals actually grew more than those upstream ...


Atmospheric Co2 Evasion, Dissolved Inorganic Carbon Production, And Net Heterotrophy In The York River Estuary, Peter Raymond, James E. Bauer, Jonathan Cole Dec 2000

Atmospheric Co2 Evasion, Dissolved Inorganic Carbon Production, And Net Heterotrophy In The York River Estuary, Peter Raymond, James E. Bauer, Jonathan Cole

VIMS Articles

Direct measurements of the partial pressure of CO2 (pCO2) and dissolved inorganic carbon (DIC) were made over a 2‐yr period in surface waters of the York River estuary in Virginia. The pCO2 in surface waters exceeded that in the overlying atmosphere, indicating that the estuary was a net source of CO2 to the atmosphere at most times and locations. Salinity‐based DIC mixing curves indicate there was also an internal source of both DIC and alkalinity, implying net alkalinity generation within the estuary. The DIC and alkalinity source displayed seasonal patterns similar to that of pCO2 and were reproducible ...


Organic Carbon Partitioning During Spring Phytoplankton Blooms In The Ross Sea Polynya And The Sargasso Sea, C.A. Carlson, Hugh Ducklow, Da Hansell, Walker O. Smith Jr. Dec 1998

Organic Carbon Partitioning During Spring Phytoplankton Blooms In The Ross Sea Polynya And The Sargasso Sea, C.A. Carlson, Hugh Ducklow, Da Hansell, Walker O. Smith Jr.

VIMS Articles

In this study we evaluate the partitioning of organic carbon between the particulate and dissolved pools during spring phytoplankton blooms in the Ross Sea, Antarctica, and the Sargasso Sea. As part of a multidisciplinary project in the Ross Sea polynya we investigated the dynamics of the dissolved organic carbon (DOC) pool and the role it played in the carbon cycle during the 1994 spring phytoplankton bloom. Phytoplankton biomass during the bloom was dominated by an Antarctic Phaeocystis sp. We determined primary productivity (PP; via H14CO3, incubations), particulate organic carbon (POC), bacterial productivity (BP; via [3H]thymidine incorporation), and DOC during ...


Concentrations And Uptake Of Neutral Monosaccharides Along 14°W In The Equatorial Pacific: Contribution Of Glucose To Heterotrophic Bacterial Activity And The Dom Flux, James Rich, Hugh Ducklow, David L. Kirchman Jun 1996

Concentrations And Uptake Of Neutral Monosaccharides Along 14°W In The Equatorial Pacific: Contribution Of Glucose To Heterotrophic Bacterial Activity And The Dom Flux, James Rich, Hugh Ducklow, David L. Kirchman

VIMS Articles

We examined concentrations and uptake of dissolved neutral monosaccharides (DNMS) in order to determine the contribution of DNMS to heterotrophic bacterial production and to the flux of dissolved organic matler (DOM) in the equatorial Pacific. DNMS concentrations were greater during El Niño‐affected months of February–April 1992 than during August–October 1992; in contrast, glucose turnover was the opposite— turnover was faster in August–October than in February–April. The variation in sugar concentrations and turnover probably resulted from El Niño‐induced changes in primary production; as El Niño waned primary production increased, which appeared to stimulate bacterial activity ...


The Magnitude And Persistence Of Soil No, N2o, Ch4, And Co, Fluxes From Burned Tropical Savanna In Brazil, M Poth, Iris C. Anderson, Et Al Nov 1995

The Magnitude And Persistence Of Soil No, N2o, Ch4, And Co, Fluxes From Burned Tropical Savanna In Brazil, M Poth, Iris C. Anderson, Et Al

VIMS Articles

Among all global ecosystems, tropical savannas are the most severely and extensively affected by anthropogenic burning. Frequency of fire in cerrado,a type of tropical savanna covering 25% of Brazil, is 2 to 4 years. In 1992 we measured soil fluxes of NO, N2O, CH4, and CO2 from cerrado sites that had been burned within the previous 2 days, 30 days, 1 year, and from a control site last burned in 1976. NO and N2O fluxes responded dramatically to fire with the highest fluxes observed from newly burned soils after addition of water. Emissions of N-trace gases after burning were ...


High Phytoplankton Growth And Production Rates In Oligotrophic Hawaiian Coastal Waters, E. A. Laws, Dg Redalje, Larry W. Haas, P. K. Bienfang, Rw Eppley, W. G. Harrison, David Karl, J. Marra Nov 1984

High Phytoplankton Growth And Production Rates In Oligotrophic Hawaiian Coastal Waters, E. A. Laws, Dg Redalje, Larry W. Haas, P. K. Bienfang, Rw Eppley, W. G. Harrison, David Karl, J. Marra

VIMS Articles

Plankton biomass, material fluxes, e.g. 14C uptake, and specific growth rates are related quantities. In the course of comparing various methods of measuring these properties in September 1982 off Oahu, Hawaii, we found specific growth rates of 1–2·d−1. Such rates approach the maximum expected values observed in laboratory cultures.


The Freshwater Medusa, Craspedacusta Sowerbii, In Matoaka Lake, Williamsburg, Virginia, Ernest F. Tresselt Jun 1950

The Freshwater Medusa, Craspedacusta Sowerbii, In Matoaka Lake, Williamsburg, Virginia, Ernest F. Tresselt

VIMS Articles

The freshwater jellyfish, Craspedacusta sowerbii Lankester, has been described from at least 19 of the 48 states (Schmitt, '39). In spite of an apparently widespread distribution it is sufficiently rare that records of its occurrence are noteworthy. Approximately 200 medusae of this species were seen in Matoaka Lake, Williamsburg, Va., on July 18, 1949.