Oceanic Cd/P ratio and nutrient utilization in the glacial Southern Ocean

摘要: During glacial periods, low atmospheric carbon dioxide concentration has been associated with increased oceanic uptake, particularly in the southern oceans. The mechanism involved remains unclear. Because ocean productivity is strongly influenced by nutrient levels, palaeo-oceanographic proxies have applied to investigate utilization surface water across transitions. Here we show that present-day cadmium and phosphorus concentrations global oceans can be explained a chemical fractionation during particle formation, whereby uptake of occurs preference phosphorus. This allows reconstruction past phosphate from cadmium/calcium ratio planktonic foraminifera. Results Last Glacial Maximum similar subantarctic today, but much smaller polar Southern Ocean, model consistent expansion sea ice which reconcile all proxy records utilization. By restricting communication between atmosphere, also provides for reduced CO2 release Ocean lower CO2.