Time-courses in the retention of food material in the bivalves Potamocorbula amurensis and Macoma balthica significance to the absorption of carbon and chromium

Alan W. Decho; Samuel N. Luoma

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USGS · 70162175

Time-courses in the retention of food material in the bivalves Potamocorbula amurensis and Macoma balthica significance to the absorption of carbon and chromium

Alan W. Decho·Samuel N. Luoma

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Abstract

Time courses for ingestion, retention and release via feces of microbial food was investigated using 2 bivalves with different feeding strategies, Potamocorbula amurensis and Macoma balthica . The results showed 2 pathways for the uptake of food material in these clams. The first is represented by an initial label pulse in the feces. The second pathway operates over longer time periods. Inert 51 Cr-labeled beads were used to determine time frames for these pathways. The first pathway, involving extracellular digestion and intestinal uptake, is relatively inefficient in the digestion of bacterial cells by P. amurensis but more efficient in M. balthica . The second pathway, involving intracellular digestion within the digestive gland of both clams, was highly efficient in absorbing bacterial carbon, and was responsible for most chromium uptake. Differences in the overall retention of microbial 51 Cr and 14 C relate not to gut-passage times but to the processing and release strategies of the food material by these 2 clams.

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Alan W. Decho, Samuel N. Luoma. 1991. Time-courses in the retention of food material in the bivalves Potamocorbula amurensis and Macoma balthica significance to the absorption of carbon and chromium. https://pubs.usgs.gov/publication/70162175

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