FORAMINIFERAL ECOTOXICOLOGY: CONSIDERING METAL SPECIATION

Physicochemical parameters in coastal and open marine settings play an integral role in the fate of Potentially Toxic Elements. It is important to understand the delicate balance in which these elements (i.e., trace metals) are exposed in sediments and in solution. Trace metal speciation is a key factor when conducting ecotoxicological studies involving marine organisms such as foraminifers and micro- or macroinvertebrates. Numerous environmental and culture studies may have overestimated trace metal concentrations because the concept of bioavailability was not properly defined and understood. To fully consider seawater chemistry prior to experimental work, it is important to recognize and quantify parameters that define (pH, alkalinity, dissolved inorganic carbon, and pCO₂) and influence (temperature, salinity, and pressure) the carbon dioxide system. These factors have greater implications when working with metals whose chemistries are controlled by carbonate and hydroxide complexation, such as copper and lead. This talk summarizes seawater physicochemical parameters to be considered during culture experiments, emphasizing trace metal speciation, and proposes strategies for improving experimental design.