Variation characteristics of ocean sediment Fe levels and their relationship with grain sizes in culture areas over a long period

Abstract Iron (Fe) is an essential component for marine ecosystems, and it related to the growth of phytoplankton communities environmental evolution in coastal area. However, effect aquaculture activities on sediment Fe levels not well studied. grain sizes are determined two cores (respectively Core C culture area A control area) Sishili Bay reveal influence cultivation over extended period. The distinguished upper sections (culture period) but equal lower (non-culture cores. core has same as before 1950s period). increased during 1950s–1970s (the algae decreased after 1970s (shellfish compared with A, indicating shellfish impose opposite effects levels. Similarly, observed be finer period coarser period, variation because important factor affecting slowing down ocean current due causes particles higher sediment. bio-deposition re-suspension play major roles coarsening decreasing