Linkages between cellular biomarker responses and reproductive success

An important issue for cellular biomarker assessments is whether they are related to higher level responses (e.g. are there linkages between cellular and organismal responses that could translate into population level effects?). The purpose of these studies was to evaluate if there were relationships between lysosomal destabilization or glutathione concentrations and gamete viability of oysters, Crassostrea virginica. Oysters were collected from reference and polluted field sites during the peak spawning period (May-June). Hepatopancreas (e.g. digestive gland) tissues were dissected and a portion was used immediately for lysosomal de-stabilization assays (based on neutral red retention), and glutathione concentrations were also determined for both hepatopancreas and gonadal tissues. Eggs and sperm from the same adults were also used to conduct embryo development assays with reference seawater collected from a clean site, site water, and also a range of Cd concentrations (the Cd exposures were used to determine if there were differences in susceptibility to pollutants). Baseline embryo development success (e.g. percent normal development when the assays were conducted with reference seawater or site water) was related to lysosomal destabilization, but not glutathione status. However, the susceptibility of embryos to metal exposures was related to glutathione status, i.e. sensitivity to Cd exposures increased with decreasing glutathione levels. These studies support the hypotheses that there are linkages between these cellular biomarker responses and embryo development success and susceptibility to pollutant stress. These kinds of effects on reproductive success could lead to subtle but significant long-term effects on recruitment and viability of oyster populations.