Spatial and temporal distribution of macrobenthos communities and their relationship with secondary front in Hangzhou Bay

Water quality in Hangzhou Bay is inferior (grade 5) because of discharged from Yangtze River and Qiantang River, factories around the bay. This study analyzed relationships between environment macrobenthic communities at 44 stations throughout Bay, based on samples collected 2006, 2016–2018, 2021. Long-term spatial temporal changed macrobenthos, influence secondary water fronts community composition, were discussed. Macrobenthos Estuary was numerically, primarily dominated by crustaceans, elsewhere polychaetes. Species that differ most abundance four identified regions bay amphipod Corophium sinensis , clam Potamocorbula laevis polychaete Amaeana occidentalis . The biomass macrobenthos different differs significantly. Taxa allocated to six feeding guilds: filter feeders omnivores predominate south while surface subsurface deposit sediments north mouth area. Negative correlations apparent abundances polychaetes Nephtys polybranchia Magelona japonica Heterospio sinica Sabella sp. A. salinity pH, positive those Sternaspis chinensis Capitellidae indet. Fine-grained fraction (silt clay) mid-salinity more suitable for macrobenthos. numbers biomasses species frontal area increased significantly relative values adjacent areas. difference each near front than 94%, main mollusks. Our baseline data this region might ultimately contribute towards improved conservation regional a better understanding ecosystem health highly polluted