Biochemical composition and bioavailability of sedimentary organic matter in two contrasting intertidal flats of Korea

Sedimentary organic matter serves as a primary food source for benthic organisms, and its quantity and composition reflect trophic conditions. To assess benthic trophic status, we analyzed biochemical constituents of sedimentary organic matter in core samples from two contrasting intertidal flats: Garolim Bay (GB) and Suncheon Bay (SB). GB sediments, primarily dominated by sandy mud, had low total organic carbon (TOC) content and low erodibility but a high proportion of labile biopolymeric carbon (BPC), indicating higher bioavailability. In contrast, SB sediments, predominantly muddy, exhibited higher TOC content and greater resuspension potential. Despite this higher TOC content, BPC accounted for 16.68 % of TOC in SB, suggesting a relatively low nutritional quality of sedimentary organic matter. These findings provide valuable insights into the benthic trophic status across contrasting sedimentary environments and underscore the critical role of resuspension in regulating organic matter availability, with broader implications for benthic ecosystem functioning within intertidal zones.