Asian Clam Potamocorbula Amurensis Research Articles

Digestive kinematics of suspension-feeding bivalves:modeling and measuring particle-processing in the gut of Potamocorbula amurensis

Particle digestion in lamellibranch bivalves is partitioned between 2 paths, an 'intestinal' path through the stomach and intestine and a 'glandular' path through the stomach, digestive gland and intestine. In the Asian clam Potamocorbula amurensis (Schrenck, 1867), the relative importance of the intestinal path increases compared to the glandular path as food availability and ingestion rate increases. The effects of changes in food availability and ingestion rate on digestive partitioning are at least as important as the effect of changes in diet observed by other investigators. Analyses of residence-time distributions of inert 9 and 44 pm particle tracers show that the gut of P amurensis can be modeled as an ideal mixing reactor (stomach and digestive gland) and an ideal plug-flow reactor (intestine) in series. This model appears to be valid for the processing of particles ≤ 9 μm in size. For particles of ≥15 μm, the ideal mixing component of the model must be modified to account for channeling of particles through the stomach to the intestine. Larger particles can enter the digestive gland, but are probably not phagocytized for intracellular digestion. Instead they may clog the ducts and tubules, limiting phagocytosis of smaller particles and potentially reducing the extent of digestion and absorption. Mixing, and the resultant intragut particle-sorting thus appear to be necessary components of a digestive strategy that incorporates intracellular digestion.

Accumulation of Butyltins in Sediments and Lipid Tissues of the Asian Clam, Potamocorbula amurensis, Near Mare Island Naval Shipyard, San Francisco Bay

Studies of butyltin compounds in soil, benthic sediments and the Asian clam Potamocorbula amurensis were conducted at the former Mare Island Naval Shipyard, and nearby Mare Island and Carquinez Straits in San Francisco Bay, California. Soils from a sandblast abrasives dump site at the shipyard contained low concentrations of mono-, di- and tributyltin (0.3–52 ng/g, total butyltin). Similarly, concentrations of total butyltin in benthic sediments from nearby Mare Island and Carquinez Straits ranged from 1.3 to 8.1 ng/g. In contrast, clams accumulated much greater concentrations (152–307 ng/g, total butyltin). Tributyltin (TBT) and dibutyltin (DBT) made up from 54–85% to 15–46%, respectively, of the total butyltin body burden of the clams. Biota Sediment Accumulation Factors (BSAFs) for butyltins in Potamocorbula were in reasonable agreement with literature values; they are greater than those of neutral hydrophobic compounds, suggesting that partitioning and binding processes may be involved in bioaccumulation. Tributyltin is a potent endocrine disrupting chemical. There is potential for long-term chronic effects of TBT in San Francisco Bay.

Remarkable invasion of San Francisco Bay (California, USA), by the Asian clam Potamocorbula amurensis. II, Displacement of a former community

Remarkable invasion of San Francisco Bay (California, USA), by the Asian clam Potamocorbula amurensis. II, Displacement of a former community