Life Sciences Commons^™

Particle Retention In Suspension-Feeding Fish After Removal Of Filtration Structures, Jennifer C. Smith, S. Laurie Sanderson

Arts & Sciences Articles

The suspension-feeding cichlids Oreochromis aureus (blue tilapia) and Oreochromis esculentus (ngege tilapia) are able to selectively retain small food particles. The gill rakers and microbranchiospines of these species have been assumed to function as filters. However, surgical removal of these oral structures, which also removed associated mucus, did not significantly affect the total number of 11–200 μm particles ingested by the fish. This result supports the hypothesis that the branchial arch surfaces themselves play an important role in crossflow filtration. Both species selectively retained microspheres greater than 50 μm with gill rakers and microbranchiospines intact as well as removed, …

Occurrence And Distribution Of The Freshwater Amphipodsgammarus Pseudolimnaeus And Gammarus Fasciatus Insoutheastern Virginia, Randolph Chambers

Arts & Sciences Articles

The freshwater amphipod, Gammarus fasciatus, and a population that keys to Gammarus pseudolimnaeusare broadly sympatric in southeastern Virginia. By documenting the successful formation of pre-copulatory mate-guarding pairs between individuals collected from Virginia and New York, we confirmed the occurrence of a G. pseudolimnaeus population strongly disjunct from the previously described range in the Mississippi and St. Lawrence River drainage basins. Gammarus pseudolimnaeus appears restricted to high-quality, spring-fed streams that occur at low density across an increasingly fragmented natural landscape in Virginia. Gammarus fasciatus, however, occurs in lakes and streams of developed landscapes that typically are more degraded, …

Short Report: Gongylonema Pulchrum Infection In A Resident Of Williamsburg, Virginia, Verified By Genetic Analysis, Jonathan D. Allen, Aurora Esquela-Kerscher

Arts & Sciences Articles

We describe the thirteenth reported case of human infection with Gongylonema spp. in the United States and the first to be confirmed as Gongylonema pulchrum. The parasite described was isolated from the oral cavity of a resident of Williamsburg, Virginia. The identity of the parasite was verified through morphological and genetic approaches, and provided the first genetic confirmation of a Gongylonema sp. in humans.

Dissolved And Particulate Organic Carbon Fluxes From An Agricultural Watershed During Consecutive Tropical Storms, Randolph Chambers

Arts & Sciences Articles

Low‐frequency high‐magnitude hydrologic events mobilize a disproportionate amount of dissolved organic carbon (DOC) from watersheds, but few studies measure the role of extreme storms in exporting organic carbon from croplands. We use high‐resolution measurements of storm runoff to quantify DOC and particulate organic carbon (POC) fluxes from an agricultural field during consecutive tropical storms that delivered 41 cm of rainfall to the Virginia Coastal Plain. Over a 2 week period, we measured exports of 22 kg DOC ha−1 and 11.3 kg POC ha−1. Ultraviolet absorbance measurements indicate that the aromatic DOC fraction systematically increased as plant‐derived aliphatic carbon was depleted …

Photochemical And Microbial Alteration Of Dissolved Organic Matter In Temperate Headwater Streams Associated With Different Land Use, Randolph Chambers

Arts & Sciences Articles

Photochemical and microbial transformations of DOM were evaluated in headwater streams draining forested and human‐modified lands (pasture, cropland, and urban development) by laboratory incubations. Changes in DOC concentrations, DOC isotopic signatures, and DOM fluorescence properties were measured to assess the amounts, sources, ages, and properties of reactive and refractory DOM under the influence of photochemistry and/or bacteria. DOC in streams draining forest‐dominated watersheds was more photoreactive than in streams draining mostly human‐modified watersheds, possibly due to greater contributions of terrestrial plant‐derived DOC and lower amounts of prior light exposure in forested streams. Overall, the percentage of photoreactive DOC in stream …

High Levels Of Maternally Transferred Mercury Do Not Affect Reproductive Output Or Embryonic Survival Of Northern Watersnakes (Nerodia Sipedon), S Y. Chinn, J D. Willson, Daniel A. Cristol, D V.V. Drewett, W A. Hopkins

Arts & Sciences Articles

No abstract provided.

A Novel Report Of Hatching Plasticity In The Phylum Echinodermata, A Frances Armstrong, Holly N. Blackburn, Jonathan D. Allen

Arts & Sciences Articles

Hatching plasticity occurs in response to a wide range of stimuli across many animal taxa, including annelids, arthropods, mollusks, and chordates. Despite the prominence of echinoderms in developmental biology and more than 100 years of detailed examination of their development under a variety of conditions, environmentally cued hatching plasticity has never been reported in the phylum Echinodermata. Here we report plasticity in the timing and stage of hatching of embryos of the sand dollar Echinarachnius parma in response to reductions in salinity. Embryos of E. parma increased their time to hatching more than twofold in response to ecologically relevant salinity …

Budding Yeast Protein Extraction And Purification For The Study Of Function, Interactions, And Post-Translational Modifications, Eva P. Szymanski, Oliver Kerscher

Arts & Sciences Articles

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously hard to disrupt. Here we describe the use of a bead mill homogenizer for the extraction of proteins into buffers optimized to maintain the functions, interactions and post-translational modifications of proteins. Logarithmically growing cells expressing the protein of interest are grown in a liquid …

Modeling The Effects Of Crab Potting And Road Traffic On A Population Of Diamondback Terrapins, Sarah Gilligand, Randolph Chambers

Arts & Sciences Articles

No abstract provided.

Integrated Carbon Budget Models For The Everglades Terrestrial-Coastal-Oceanic Gradient: Current Status And Needs For Inter-Site Comparisons., Randolph Chambers

Arts & Sciences Articles

Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. e Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets

for riverine mangrove, freshwater marsh, and seagrass meadows, …