Distribution of dissolved aluminum in the Southern Yellow Sea: Influences of a dust storm and the spring bloom

Abstract

The distribution of dissolved aluminum (Al) in the Southern Yellow Sea (SYS) was investigated in the spring of 2007. Following an episode of enhanced Asian dust storm inputs over the SYS at the beginning of the observation period, surface concentrations were enhanced up to 197 nM at section A and then returned to 23 nM towards the end of cruise three weeks later. The concentrations of dissolved Al were higher in the top layer and decreased with depth during the first stage of the observations, which showed the effects of dust input. A large-scale diatom bloom occurred four to five days after the dust event in the study area. The concentrations of dissolved Al in the top mixed layer of the central SYS decreased sharply during the spring bloom. The vertical profiles of dissolved Al were similar to those of silicate during the bloom, which indicated biological mediation of dissolved Al in the SYS. Input fluxes of dissolved Al from atmospheric deposition, riverine input and exchanges with the East China Sea and Bohai were estimated, of which atmospheric deposition was the dominant source of dissolved Al in the Yellow Sea (YS). Utilizing the dissolved Al content with the total input flux, a 148 ± 32 day residence time of dissolved Al in the YS was inferred.