Zinc and silicon biogeochemical decoupling in the North Pacific Ocean

Abstract In the ocean, zinc (Zn) is an important element for biological activity and biogeochemistry. The distribution of dissolved Zn in global ocean similar to that silica (Si). Previous model-based experiments proposed Southern Ocean hypothesis: high Zn/P uptake ratio by phytoplankton leads Zn-depleted surface water this anomaly transported into interior associated with mode formation, resulting a Si. However, recent observational data from North Pacific showed there decoupling Si: correlation between Si breaks down Pacific. This study investigates process cycle causes using model. We conducted model experiment various speeds but it was not easy reproduce concentrations Pacific, indicating additional mechanisms are required produce By considering sources continental shelves Sea Okhotsk Bering Sea, we found concentration Zn–Si were reproduced, consistent data. Our result suggests supply coastal regions has role causing decoupling.