Stable carbon and nitrogen isotope analysis and environmental characteristics of benthic animals in Ushibashi Estuary, Miyagi Prefecture

To clarify the effect of irrigation drainage from paddy fields on an estuarine tidal flat (Ushibashi Estuary, Miyagi Prefecture),we investigated carbon and nitrogen stable isotope ratios (δ13C δ15N) organic matters within fields, agricultural channels (rivers),and flats, those 18 species benthic consumers March to December 2020. The sediments had lower δ13C δ15N at riverward station (δ13C: -27.1 -25.4‰; δ15N: 2.7 4.3‰) than seaward -26.5 -20.5‰; 3.3 7.1‰).The total ratio (C/N) was low in (3.3 7.5),and it estimated that matter derived freshwater seawater microalgae deposited estuary. However, direct supply field river particulate (POM) not detected. sources most animal residing flats were presumed be marine origin (marine- POM microphytobenthos) by a δ13C-based mixing model (simmr).The contribution food resource for some bivalves polychaetes higher terrestrial sources. estuaries serve as sink storing rivers, providing unique habitat animals.