In response to the 2010 Deepwater Horizon oil spill, over 1 million gallons of dispersant were applied in Gulf of Mexico offshore waters; Corexit 9500 was the most applied dispersant. The impact on organisms in nearshore and freshwaters has received little scrutiny. Acute 48 h toxicity of Corexit 9500 and a new hyperbranched polyethylenimine (HPEI) dispersant-like compound were evaluated for the freshwater indicator organism, Daphnia magna and for larval and early spat stages of the Eastern oyster, Crassostrea virginica.
View Article and Find Full Text PDFThe frequency and intensity of anoxic and hypoxic events are increasing worldwide, creating stress on the organisms that inhabit affected waters. To understand the effects of low dissolved oxygen stress on oysters, hatchery-reared oysters were placed in cages and deployed along with continuously recording environmental data sondes at a reef site in Mobile Bay, AL that typically experiences low oxygen conditions. To detect and measure sublethal stress, we measured growth and survival of oysters as well as expression of three biomarkers, heat shock protein 70 (HSP70), hypoxia inducible factor (HIF) and phospho-p38 MAP kinase, in tissues from juvenile and adult oysters.
View Article and Find Full Text PDFThe genetic structure of inshore aquatic populations can be influenced by a number of factors, including coastal configurations, flow rates, and local adaptation. Properties such as salinity and temperature can differ significantly along the coasts and into the bays and rivers that contribute to these systems. Within these environments, low migratory euryhaline species provide a unique system to examine how these factors influence population structure, even when these populations are continuously distributed.
View Article and Find Full Text PDFThe protist Labyrinthula zosterae (Phylum Bigyra, sensu Tsui et al. 2009) has been identified as a causative agent of wasting disease in eelgrass (Zostera marina), of which the most intense outbreak led to the destruction of 90% of eelgrass beds in eastern North America and western Europe in the 1930s. Outbreaks still occur today, albeit at a smaller scale.
View Article and Find Full Text PDFSexual selection is responsible for the evolution of some of the most elaborate traits occurring in nature, many of which play a vital role in competition over access to mates and individual reproductive fitness. Because expression of these traits is typically regulated by sex-steroids there is a significant potential for their expression to be affected by the presence of certain pollutants, such as endocrine disrupting compounds. Endocrine disruptors have been shown to alter primary sexual traits and impact reproduction, but few studies have investigated how these compounds affect secondary sexual trait expression and how that may, in turn, impact mating dynamics.
View Article and Find Full Text PDFSymptoms characteristic of wasting disease, thought to result from infection by protozoan pathogens (i.e. Labyrinthula spp.
View Article and Find Full Text PDFFor a variety of species, changes in the expression of heat shock proteins (HSP) have been linked to key developmental changes, i.e., gametogenesis, embryogenesis, and metamorphosis.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
June 2007
Many species of pipefish exhibit a reversal of parental roles, in which females insert eggs into the brood pouch of the male where they are incubated until the end of embryonic development. While the significance of the male brood pouch has been examined for over a century, the role of the pouch is still unclear. One possible function is to aid in osmoregulation by buffering embryos from the external environment.
View Article and Find Full Text PDFPhenolics in marine brown algae have been thought to follow a latitudinal gradient with high phenolic species in high latitudes and low phenolic species in low latitudes. However, tropical brown algae from the western Caribbean have been shown to be high in phlorotannin concentration, indicating that latitude alone is not a reasonable predictor of marine plant phenolic concentrations. This study shows that the range of high phenolic phaeophytes is not limited to the western Caribbean but encompasses the western tropical Atlantic, including Bermuda and the Caribbean, where algal phlorotannin concentrations can be as high as 25% dry weight (DW).
View Article and Find Full Text PDFMarine allelochemicals generally are present in greater quantity and diversity in tropical than in temperate regions. Marine algal polyphenolics have been reported as an apparent exception to this biogeographic trend, with literature values for phenolic concentrations significantly higher in temperate than in tropical brown algae. In contrast, our results, the first reported for Caribbean brown algae (orders Dictyotales and Fucales), show that many species have high phenolic levels.
View Article and Find Full Text PDF