Relationships among the climate-relevant gases during the Southern Ocean bloom season

The ocean plays an essential role in regulating the sources and sinks of climate-relevant gases, like CO₂, N₂O and dimethyl sulfide (DMS), thus influencing global climate change. Although the Southern Ocean is known to be a strong carbon sink, a significant DMS source and possibly a large source of N₂O, our understanding of the interaction among these climate-relevant gases and their potential impacts on climate change is still insufficient in the Southern Ocean. Herein, we analyzed parameters, including surface water pCO₂, dissolved inorganic carbon (DIC), alkalinity (TA), DMS and N₂O in the water column, collected during the austral summer of 2015-2016 in the 32nd Chinese Antarctic Research Expedition (CHINARE) at the tip of Antarctic Peninsula. A positive correlation between DMS and pCO₂ (indicated by deficit of DIC, ∆DIC, refer to values in 100 m) was observed in waters above 75 m, whereas no correlation between N₂O saturation anomaly (SA) and DMS, ∆DIC was found. In the area with stable stratification with phytoplankton bloom, significant DMS source and strong CO₂ uptake with weak N₂O emission were observed. Conversely, strong mixing or upwelling area was shown to be a strong marine CO₂ source and significant N₂O release with weak DMS source.