Evolution of paleoproductivity in the Antarctica Ross Sea since the Last Glacial Maximum

To reveal the past climate changes and ecological system evolution in Antarctica and provide key information, predict the impact of future climate change, and improve the accuracy of climate models, the Ross Sea paleoproductivity was studied by testing and analyzing the organic carbon, nitrogen and their isotopes, and major and trace elements of the ANT32-RB16C core in the Antarctic Ross Sea. The evolution of paleoproductivity in the Ross Sea since 24.8 cal.kaBP (Last Glacial Maximum) was reconstructed. Results show that the ANT32-RB16C sedimentation record well reflected the change in paleoproductivity in three stages including the Last Glacial Maximum, the last deglaciation, and the Holocene, which is consistent with the change in temperature in the Antarctica. The core record shows a higher productivity during the warm period and a lower productivity during the cold period. Specifically, from 24.8 to 17.5 cal.kaBP, the ocean productivity was low, from 17.5 to 11.7 cal.kaBP, the ocean productivity changed from low to high status, and during 11.7～0 cal.kaBP, the ocean productivity gradually recovered. The paleoproductivity of the Ross Sea was influenced obviously by regional climate change, especially climate events such as the Antarctic Circumpolar Reversal, Younger Dryas, and Little Ice Age etc., which had a heavy impact on the evolution of paleoproductivity in the study area. At the same time, sea ice, nutrients, and so on play important roles in the evolution of paleoproductivity in the Ross Sea. In other words, during the cold period, sea ice coverage increased and the thickness of surface seawater layer slowed down the upwelling of deep water rich in nutrient salt. Meanwhile, there was a relative lack of nitrates in surface seawater, resulting in lower productivity at that time.