Oxygen depletion recorded in upper waters of the glacial Southern Ocean.

ABSTRACT: Oxygen depletion in the upper ocean is commonly associated with poor ventilation and storage of respired carbon, potentially linked to atmospheric CO2 levels. Iodine to calcium ratios (I/Ca) in recent planktonic foraminifera suggest that values less than ∼2.5 μmol mol(-1) indicate the presence of O2-depleted water. Here we apply this proxy to estimate past dissolved oxygen concentrations in the near surface waters of the currently well-oxygenated Southern Ocean, which played a critical role in carbon sequestration during glacial times. A down-core planktonic I/Ca record from south of the Antarctic Polar Front (APF) suggests that minimum O2 concentrations in the upper ocean fell below 70 μmol kg(-1) during the last two glacial periods, indicating persistent glacial O2 depletion at the heart

SUBMITTER: Lu Z 

PROVIDER: S-EPMC4821880 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature