Asian dust initiated early spring bloom in the northern East/Japan Sea

Abstract

Data for the TOMS aerosol index and SeaWiFS chlorophyll a clearly indicate that an early spring bloom in the northern East/Japan Sea can be initiated during the Asian dust event in association with precipitation. Spring bloom is normally initiated in this area as the surface mixed layer becomes shallower than critical depth, in accordance with Sverdrup's critical depth hypothesis. However, after the passage of Asian dust accompanied by precipitation, spring bloom was initiated about one month earlier than the bloom during non‐dust event years. We found that deepening of critical depth coincided with the early spring bloom observed during wet‐dust events. This early initiation of spring bloom indicates that the supply of bio‐available nutrients such as iron through wet deposition induces deepening of the critical depth, which results in such an early initiation of the bloom in the area.