Indicators of environmental stress: cellular biomarkers and reproductive responses in the Sydney rock oyster (Saccostrea glomerata)

Abstract

We measured a suite of common biomarker responses for the first time in the Sydney rock oyster Saccostrea glomerata to evaluate their utility as biological effects measures for pollution monitoring. To examine the relationship between biomarker responses and population level effects, fertilisation and embryo development assays were also conducted. Adult oysters were deployed in two contaminated estuaries and a reference estuary in Sydney, Australia. The concentrations of various contaminants (metals and polycyclic aromatic hydrocarbon, PAHs) were quantified in oyster's tissue from each site and both metals and total PAHs were significantly elevated in contaminated estuaries relative to the reference estuary. Lysosomal membrane destabilisation, lipid peroxidation levels and glutathione (GSH) concentrations were measured in the digestive gland of oysters. Of all biomarkers measured, lysosomal membrane destabilisation proved to be the most useful indicator of oysters facing anthropogenic stress and we suggest this may be an especially useful biomarker for incorporation into local environmental monitoring programs. Moreover, lysosomal membrane destabilisation showed good correlations with fertilisation, normal embryo development and estuary status. GSH and lipid peroxidation were not as valuable for distinguishing between estuaries exposed to differing levels of anthropogenic stress, but did provide additional valuable information regarding overall health status of the oysters.

Physiological and cellular responses of oysters (Crassostrea hongkongensis) in a multimetal‐contaminated estuary

“…Oysters (C. hongkongensis) in most sampling sites contained high concentrations of several metals such as Cd, Cu, and Zn. If we converted the metal concentrations to a wet weight basis using a wet to dry weight ratio of oysters (8)(9)(10) measured in the present study, Cd concentrations in oysters would exceed the 2 mg/kg safety limit in most of the sites [19]. Furthermore, our measurements suggested that the dominant metal pollution on the eastern side was Cu, Ni, and Zn, similar to an earlier study identifying 2 hot spots of Cu pollution in surface sediments on the eastern side of the Pearl River estuary [5].…”

Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects

“…A significant deterioration of lysosomal membranes was observed in oysters exposed to resuspended contaminated sediments, with destabilization rates as high as 60% in some treatments. Recent studies on the Sydney rock oyster and other bivalves have shown that these rates of destabilization are associated with a significant reduction in normal embryo development and suggest that these oysters are suffering from significant stress . In addition, these rates of destabilization have been observed in oysters within highly modified and more contaminated estuaries , where the combined stressors also resulted in changes in communities of larval fish bacteria , and invertebrates .…”

“…TSS ¼ total suspended solids; MDA ¼ malondialdehyde. significant stress [47][48][49]. In addition, these rates of destabilization have been observed in oysters within highly modified and more contaminated estuaries [32,50], where the combined stressors also resulted in changes in communities of larval fish [51] bacteria [52,53], and invertebrates [2].…”

The ecology, evolution, impacts and management of host–parasite interactions of marine molluscs

“…In a related example, salinities greater than 15 ppt are associated with P.marinus infection and Dermo disease among subtidal Crassostrea virginica oysters (Ford and Tripp, 1996;Elston and Ford, 2011;Burge et al, 2014;Lafferty et al, 2015), but not among intertidal oysters that in many instances appear to be thrive in high salinity waters (O'Beirn et al, 1997;Bobo et al, 1997;Drexler et al, 2013;Volety et al, 2009Volety et al, , 2014. In some instances, abiotic factors interact to influence the production and activity of enzymes associated with cellular defenses (e.g., Akberali and Trueman, 1985;Jenny et al, 2002;Edge et al, 2012;Soudant et al, 2013). Sublethal multi-stressor impacts can be evaluated in molluscs using a suite of 'subtle' cellular biomarkers, including heat shock proteins (e.g., Akberali and Trueman, 1985;Ringwood et al, 1999Ringwood et al, , 2002Sung et al, 2011;Edge et al, 2012).…”

“…In some instances, abiotic factors interact to influence the production and activity of enzymes associated with cellular defenses (e.g., Akberali and Trueman, 1985;Jenny et al, 2002;Edge et al, 2012;Soudant et al, 2013). Sublethal multi-stressor impacts can be evaluated in molluscs using a suite of 'subtle' cellular biomarkers, including heat shock proteins (e.g., Akberali and Trueman, 1985;Ringwood et al, 1999Ringwood et al, , 2002Sung et al, 2011;Edge et al, 2012).…”