Ekman pumping dynamics and atmospheric aerosol concentration enhancing nitrogen and carbon uptake in the Arabian Sea during winter
摘要
New and primary productivity measurements using δ15N and δ13C tracer technique were conducted in the Arabian Sea (AS) during the cruise from 17th December 2019 to 6th January 2020. New and primary productivity in the AS are mainly controlled by hydrodynamic and satellite-derived meteorological parameters such as wind speed, wind stress, sea surface temperature, aerosols concentration and Ekman pumping. Analysis of cruise samples from the 14 stations showed high surface productivity in the Ekman mass transport area followed by aerosol deposition region. New production measured 46.998 mmol N m2 d−1. Regenerated production was 37.060 mmol N m2 d−1 from ammonium and 39.220 mmol N m2 d−1 from urea. Primary production reached 89.595 mmol N L−1d−1. Rainfall events at some stations divulgated and not correlated with increased production, suggesting complex nutrient dynamics influenced by surface stratification and nutrient dilution. The f-ratio revealed lower nitrate uptake in open ocean regions compared to areas influenced by aerosol deposition and Ekman transport. This study characterized the intricate interplay of physical and biogeochemical processes affecting primary production in the AS.