<b>The driving factors of dimethylated sulfur compounds in the Pearl River Estuary</b><b>: the</b> <b>nonnegligible role of </b><b><i>Synechococcus</i></b>

Estuaries serve significant roles in the global dimethylated sulfur compounds (DSCs) cycle, whereas the driving factors and biological contribution still need to be better understood. To explore the factors controlling the spatial variabilities of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) and, the role of phytoplankton in DSCs emissions in estuaries, a field investigation was conducted alongside diluted water in the Pearl River Estuary (PRE). The influx of the Pearl River diluted water (PRDW) caused a shift in higher DMSP and DMS values from the nearshore to offshore. Interestingly, the abundance of <i>Synechococcus</i> exhibited significant positive correlations with DMS and DMSP, compared to eukaryotic phytoplankton. These results indicated that <i>Synechococcus</i> was an essential biological factor driving the DSCs production in estuaries. This study provides a new insight to clarify the nonnegligible role of <i>Synechococcus</i> in the biogenic sulfur cycle, in which its contribution must be considered in further estuarine investigation.