Stable isotope analysis of food sources for salt marsh snails

摘要: Food sources for the deposit-feeding gastropods Assiminea japonica and Angustas- siminea castanea (Gastropoda: Assimineidae) were estimated using stable carbon nitrogen iso- tope ratios. We collected animals potential food materials in reed marshes of Nanakita River estuary, eastern part Miyagi Prefecture, Japan. Feeding experiments also conducted to confirm whether snails assimilate 4 types diets. The isotope ratios both assimineid species (mean ± 1 SD: A. japonica, -20.7 0.3‰; castanea, -19.8 0.5‰) closer that deposited organic matter from lagoon water (-20.7 0.3‰) than those litter (-25.4 0.1‰) surface soil marsh (-26.3 0.1‰). fed mat- ter showed δ 13 C values similar control before feeding species. or diet, however, revealed these able detritus under laboratory conditions. These findings suggest salt utilized mainly field. Microal- gae such as phytoplankton benthic diatoms are considered be important 2 assimineids inhabiting estuary.