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Full-Text Articles in Life Sciences
Temporal Shifts In Top-Down Vs. Bottom-Up Control Of Epiphytic Algae In A Seagrass Ecosystem, Ma Whalen, Je Duffy, Jb Grace
Temporal Shifts In Top-Down Vs. Bottom-Up Control Of Epiphytic Algae In A Seagrass Ecosystem, Ma Whalen, Je Duffy, Jb Grace
VIMS Articles
In coastal marine food webs, small invertebrate herbivores (mesograzers) have long been hypothesized to occupy an important position facilitating dominance of habitat-forming macrophytes by grazing competitively superior epiphytic algae. Because of the difficulty of manipulating mesograzers in the field, however, their impacts on community organization have rarely been rigorously documented. Understanding mesograzer impacts has taken on increased urgency in seagrass systems due to declines in seagrasses globally, caused in part by widespread eutrophication favoring seagrass overgrowth by faster-growing algae. Using cage-free field experiments in two seasons (fall and summer), we present experimental confirmation that mesograzer reduction and nutrients can promote …
Multiple Predator Species Alter Prey Behavior, Population Growth, And A Trophic Cascade In A Model Estuarine Food Web, Pl Reynolds, Jf Bruno
Multiple Predator Species Alter Prey Behavior, Population Growth, And A Trophic Cascade In A Model Estuarine Food Web, Pl Reynolds, Jf Bruno
VIMS Articles
Predators can influence prey population dynamics by affecting prey behaviors with strong fitness consequences, with cascading effects on lower trophic levels. Here, we demonstrate that multiple predator species can nonconsumptively influence prey population growth and the strength of a trophic cascade in a model marine community. We exposed the herbivorous amphipod Ampithoe longimana to olfactory and visual cues from three common predators (pinfish, mud crabs, brown shrimp) singly and together in a multiple-predator assemblage to quantify the nonconsumptive effects (NCEs) of predator identity and the presence of multiple predators on prey population and community-level metrics. The presence of predator cues, …
Modeling The Effect Of Hypoxia On Macrobenthos Production In The Lower Rappahannock River, Chesapeake Bay, Usa, Samuel Kersey Sturdivant, Mark Brush, Robert J. Diaz
Modeling The Effect Of Hypoxia On Macrobenthos Production In The Lower Rappahannock River, Chesapeake Bay, Usa, Samuel Kersey Sturdivant, Mark Brush, Robert J. Diaz
VIMS Articles
Hypoxia in Chesapeake Bay has substantially increased in recent decades, with detrimental effects on macrobenthic production; the production of these fauna link energy transfer from primary consumers to epibenthic and demersal predators. As such, the development of accurate predictive models that determine the impact of hypoxia on macrobenthic production is important. A continuous-time, biomass-based model was developed for the lower Rappahannock River, a Bay tributary prone to seasonal hypoxia. Phytoplankton, zooplankton, and macrobenthic state variables were modeled, with a focus on quantitatively constraining the effect of hypoxia on macrobenthic biomass. This was accomplished through regression with Z': a sigmoidal function …
Fish Species Distribution In Seagrass Habitats Of Chesapeake Bay Are Structured By Abiotic And Biotic Factors, Jason J. Schaffler, Jacques Van Montfrans, Cynthia M. Jones, R J. Orth
Fish Species Distribution In Seagrass Habitats Of Chesapeake Bay Are Structured By Abiotic And Biotic Factors, Jason J. Schaffler, Jacques Van Montfrans, Cynthia M. Jones, R J. Orth
VIMS Articles
Seagrass habitats have long been known to serve as nursery habitats for juvenile fish by providing refuges from predation and areas of high forage abundance. However, comparatively less is known about other factors structuring fish communities that make extensive use of seagrass as nursery habitat. We examined both physical and biological factors that may structure the juvenile seagrass-associated fish communities across a synoptic-scale multiyear study in lower Chesapeake Bay. Across 3years of sampling, we collected 21,153 fish from 31 species. Silver Perch Bairdiella chrysoura made up over 86% of all individuals collected. Nine additional species made up at least 1% …
Effects Of Seasonal Hypoxia On Macrobenthic Production And Function In The Rappahannock River, Virginia, Usa, Sk Sturdivant, Rochelle D. Seitz, R. J. Diaz
Effects Of Seasonal Hypoxia On Macrobenthic Production And Function In The Rappahannock River, Virginia, Usa, Sk Sturdivant, Rochelle D. Seitz, R. J. Diaz
VIMS Articles
Since colonial times, anthropogenic effects have eroded Chesapeake Bay’s health, resulting in an increase in the extent and severity of hypoxia (≤ 2 mg O2 l-1), adversely affecting community structure and secondary production of macrobenthos in the Bay and its tributaries. The influence of hypoxia on macrobenthic communities is well documented, but less well known is the regulatory effect of hypoxia on macrobenthic production. Changes in macrobenthic production were assessed in the lower Rappahannock River, a sub-estuary of Chesapeake Bay, in an area known to experience seasonal hypoxia. During the spring, summer, fall, and following spring of …
Internal Versus External Drivers Of Periodic Hypoxia In A Coastal Plain Tributary Estuary: The York River, Virginia, Sj Lake, Mark Brush, Iris C. Anderson, Hi Kator
Internal Versus External Drivers Of Periodic Hypoxia In A Coastal Plain Tributary Estuary: The York River, Virginia, Sj Lake, Mark Brush, Iris C. Anderson, Hi Kator
VIMS Articles
The formation of periodic hypoxia within tributary estuaries, and its relationship to the spring-neap tidal cycle, has been well documented in several systems along the US east coast. However, the importance and scale of other physical and biological processes, which ultimately control the frequency and spatial extent of hypoxia, are less well understood. This study synthesized in situ measurements, metabolic incubations, and high-resolution water quality monitoring into a spatially explicit, temporally integrated mass balance to examine the significance of multiple organic matter sources and oxygen sinks in relation to hypoxia in the York River estuary (YRE), Virginia, USA. Results highlight …
Seed Burial In Eelgrass Zostera Marina: The Role Of Infauna, Nj Blackburn, R J. Orth
Seed Burial In Eelgrass Zostera Marina: The Role Of Infauna, Nj Blackburn, R J. Orth
VIMS Articles
Seed burial is a vital process that influences small- and large-scale plant population patterns and is frequently mediated by soil-dwelling invertebrates. Despite its importance in terrestrial systems, very little is known about seed burial in seagrasses. The goal of this work was to determine the role that benthic infauna play in the burial of Zostera marina seeds. Mesocosm experiments studying seed burial depth, seed burial rate, and particle burial and redistribution using beads, were conducted in defaunated sediment cores populated with single specimens of infauna with different modes of feeding and thus bioturbation effects: Amphitrite ornata (downward conveyor deposit feeder), …
Sperm Swimming Speeds In The Eastern Oyster Crassostrea Virginica (Gmelin, 1791), Roger L. Mann, Mark Luckenbach
Sperm Swimming Speeds In The Eastern Oyster Crassostrea Virginica (Gmelin, 1791), Roger L. Mann, Mark Luckenbach
VIMS Articles
Oysters, like the vast majority of sessile marine invertebrates, shed sperm and eggs into the water column where fertilization subsequently occurs. The fate of the gametes depends on their passive movements at various scales in a high-viscosity environment, the longevity of the sperm's ability to affect oriented movement, the rate of sperm movement toward the egg target, and the ability of sperm to effect fertilization. Oyster sperm swim in a helical pattern with a mean forward progression velocity of 0.057 +/- 0.010 mm/sec (SE; n = 25) with the 95 percentile range extending from 0.036-0.078 mm/sec, a value comparable with …
Microphytobenthos And Benthic Macroalgae Determine Sediment Organic Matter Composition In Shallow Photic Sediments, Ak Hardison, Elizabeth A. Canuel, Iris C. Anderson, C. R. Tobias, B. Veuger, M. N. Waters
Microphytobenthos And Benthic Macroalgae Determine Sediment Organic Matter Composition In Shallow Photic Sediments, Ak Hardison, Elizabeth A. Canuel, Iris C. Anderson, C. R. Tobias, B. Veuger, M. N. Waters
VIMS Articles
Microphytobenthos and benthic macroalgae play an important role in system metabolism within shallow coastal bays. However, their independent and interactive influences on sediment organic matter (SOM) are not well understood. We investigated the influence of macroalgae and microphytobenthos on SOM quantity and quality in an experimental mesocosm system using bulk and molecular level (total hydrolyzable amino acids, THAA; phospholipid linked fatty acids, PLFA; pigment) analyses. Our experiment used an incomplete factorial design made up of two factors, each with two levels: (1) light (ambient vs. dark) and (2) macroalgae (presence vs. absence of live macroalgae). Over the course of the …
Combining Observations And Numerical Model Results To Improve Estimates Of Hypoxic Volume Within The Chesapeake Bay, Usa, A.J. Bever, Marjorie A.M. Friedrichs, Carl T. Friedrichs, M. E. Scully, Lyon Lanerolle
Combining Observations And Numerical Model Results To Improve Estimates Of Hypoxic Volume Within The Chesapeake Bay, Usa, A.J. Bever, Marjorie A.M. Friedrichs, Carl T. Friedrichs, M. E. Scully, Lyon Lanerolle
VIMS Articles
The overall size of the dead zone within the main stem of the Chesapeake Bay and its tidal tributaries is quantified by the hypoxic volume (HV), the volume of water with dissolved oxygen (DO) less than 2 mg/L. To improve estimates of HV, DO was subsampled from the output of 3-D model hindcasts at times/locations matching the set of 2004-2005 stations monitored by the Chesapeake Bay Program. The resulting station profiles were interpolated to produce bay-wide estimates of HV in a manner consistent with nonsynoptic, cruise-based estimates. Interpolations of the same stations sampled synoptically, as well as multiple other combinations …
Nondaily Deposition Of Striae In The Bay Scallop Argopecten Irradians (Concentricus) In The Laboratory, P Hollyman, Mark Luckenbach, Ca Richardson
Nondaily Deposition Of Striae In The Bay Scallop Argopecten Irradians (Concentricus) In The Laboratory, P Hollyman, Mark Luckenbach, Ca Richardson
VIMS Articles
Small (similar to 15 mm) and large (similar to 30 mm) calcein-marked bay scallops, Argopecten irradians, held for 2, 4, and 6 wk in the laboratory under natural illumination and conditions of high and low flow rates deposited significantly more striae on the surface of the left (dark) shell valve compared with the right (light) shell valve. Small scallops deposited an average of 0.55 stria per day, 0.42 stria per day, and 0.34 stria per day, respectively, during the 2-, 4-, and 6-wk experiments, whereas large scallops had a lower frequency of stria formation (0.20 stria per day, 0.18 stria …
Molecular And Functional Ecology Of Aquatic Microbial Symbionts, Hans-Peter Grossart, Lasse Riemann, Kam W. Tang
Molecular And Functional Ecology Of Aquatic Microbial Symbionts, Hans-Peter Grossart, Lasse Riemann, Kam W. Tang
VIMS Articles
No abstract provided.
The Maredat Global Database Of High Performance Liquid Chromatography Marine Pigment Measurements, J. Peloquin, Walker O. Smith Jr.
The Maredat Global Database Of High Performance Liquid Chromatography Marine Pigment Measurements, J. Peloquin, Walker O. Smith Jr.
VIMS Articles
A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Oceanographie de Villefranche (LOV), with an additional 17% and 19% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl …
Age, Growth, And Reproductive Biology Of Cownose Rays In Chesapeake Bay, Robert A. Fisher, Garrett C. Call, R. Dean Grubbs
Age, Growth, And Reproductive Biology Of Cownose Rays In Chesapeake Bay, Robert A. Fisher, Garrett C. Call, R. Dean Grubbs
VIMS Articles
The Cownose Ray Rhinoptera bonasus is an opportunistic predator of benthic invertebrates and has had a long history of negative interactions with commercial shellfish industries. Most recently, Cownose Rays have been implicated in negatively affecting the recovery of bay scallop Argopecten irradians stocks in North Carolina and oyster restoration and commercial aquaculture efforts in Chesapeake Bay. A mitigation attempt to decrease predation on shellfish has resulted in an unregulated fishery for Cownose Rays. Cownose Ray life history suggests that they are highly susceptible to overexploitation. We determined age, growth, and size at maturity for Cownose Rays collected in Chesapeake Bay. …