2020 Volume 63 Issue 4 Pages 165-170
Nutrients such as nitrogen compounds, which control the amount of phytoplankton near the ocean's surface, are mostly supplied by deep ocean circulation. In the western North Pacific subtropical area, the amount of nutrients supplied to the ocean's surface in this manner is extremely small, indicating the importance of nutrients sourced from the atmosphere instead. To better understand this process, we developed improved numerical models by combining an atmospheric regional chemical transport model (WRF-CMAQ) and a 3-D lower trophic-marine ecosystem model (NEMURO). Phytoplankton amount increases noticeably in low- to mid-latitude regions (subtropical areas) when atmospheric nitrogen deposition was considered. This indicates that the atmospheric nitrogen compounds emitted from East Asia are likely to play an important role in increasing the amount of phytoplankton in the western North Pacific subtropical area.