A series of aquaria containing various combinations of water, sediments, and molluscs was used to investigate the effects of molluscs on alkalinity of the water. Live molluscs acidified the water, and dead decomposing molluscs were associated with an increase in alkalinity in the aquaria. Aquaria containing dead molluscs had more stable alkalinity concentrations than other aquaria when all received additions of natural acid rain (pH 4.1). Nonmolluscan invertebrates liberated acid-neutralizing materials from the sediments but the source was quickly depleted. A hypothesis of temporal disjunction between periods of molluscan acid and base production is given which indicates a potential role for molluscs in the sources and cycling of carbonates in acidifying environments.
Spatial and dietary sources of elevated mercury exposure in white-tailed eagle nestlings in an Arctic freshwater environment
