Abstract: It is important to investigate the spatiotemporal distribution and recent trend of net primary productivity (NPP) in the Southern Ocean because the region is the largest carbon sink within the global ocean. Based on NPP, sea surface temperature (SST) and sea ice concentration (SIC) data of the Southern Ocean during 2003–2016, the spatiotemporal distribution and recent trend of NPP in the Southern Ocean, and the correlation of both SST and SIC with NPP were analyzed. The results showed that annual average NPP within the study area was in the range 64.00–2.26 × 105 mg C m?2·a?1, and annual NPP of the Indian Ocean sector, Atlantic Ocean sector and Pacific Ocean sector was 0.568, 0.431 and 0.262 Gt C·a?1, respectively. In the Southern Ocean, NPP presented regional variation. For example, NPP around the Antarctic continent and in the Weddell Sea was low; however, areas near islands showed higher NPP. Moreover, high values were also found near the front of the ice shelf. Because of the seasonal change in solar radiation, NPP in the Southern Ocean has seasonal variation with highest (lowest) values in austral summer (winter). During 2003–2016, significant increase in NPP occurred only in the Indian Ocean sector. Furthermore, the trend of NPP in each sector was found correlated with the variation of SST and SIC.

Key words: NPP, Southern Ocean, spatiotemporal distribution, recent trend, influencing factors