Climate change,polar ice and Atlantic Ocean
本讲教师：Hong Chin Ng
Research experience: 1)Investigation of nutrient cycling at the high latitudes during climate change using Siisotope analyses; 2) Investigation of sedimentary 231Pa/230Th as proxy of AtlanticMeridional Overturning Circulation rate and its deglacial application. Abstract: At present, atmospheric CO2 level is experiencing the largest and fastest rise in human history. Such a rise causes global climate warming, which has been associatedwith global continental and sea ice melting observed today. The widespread meltingmight have multiple effects on the ocean system, I am particularly interested in studying the potential impacts on: Ô the Atlantic Ocean circulation strength, and 2the marine biogeochemical cycling of nutrients. I found that melting of northern polar ice played a key role in driving a two-step Atlantic Ocean circulation slowdown,with a positive feedback sustaining continued iceberg calving and climate change atthe beginning of deglaciation. This finding has implications for the modern climatechange, in the light of rapid melting of Greenland and Arctic ice. In addition, I investigated the benthic component of the marine biogeochemical cycling of Si. Myresults show a net benthic flux of Si out of the sediment to the ocean driven by dissolution of biogenic opal (such as diatoms and sponges) and potentially glacially-derived amorphous Si at coastal Greenland.