Variability in responses to nutrients and trace elements, and transmission of stressor effects through an estuarine food web

Abstract

Marine bivalve molluscs such as the blue mussel ( Mytilus edulis ) and the soft shell clam ( Mya arenaria ) have been used as sentinel organisms of contaminant bioavailability and the biological consequences of contaminant exposure. Biological responses that may contribute to the impairment of reproductive and developmental processes include responses that can be categorized as interfering with bioenergetic processes such as feeding and nutrient allocation; biosynthetic processes, such as the synthesis of energy stores; and morphogenic processes, such as those involved in structural development. Case studies within New Bedford and Boston Harbors (Massachusetts) are used to examine the relationship between contaminant uptake and effects on the reproductive cycle and bioenergetics of mussels and soft shell clams. The results observed illustrate that disruption in bioenergetics in bivalve molluscs exposed to chemical contaminants can result in loss of reproductive output and increased susceptibility to disease. Differences in the extent of reproductive impairment may be linked specifically to energetic strategies of individual species.