The oxygen content of the world’s oceans is essential for the survival of most organisms and therefore has severe economic impact when conditions deteriorate. With ongoing global climate change, the oceans are warming and therefore less oxygen can be dissolved into the sea water. In addition, increasing pollutants are flushed into the oceans such that more and more areas become starved of oxygen and thus life. To understand the impact of decreasing oxygen content on the marine ecosystem, the history of changing oxygen content can teach us what to expect in the future. Foraminifera are the ultimate tool to study these changes, as they have been shown to not only survive but also calcify, which is essential for using their geochemistry, under low-oxygen conditions. During calcification they are incorporating the geochemical signature of the water conditions at time of calcification into their shells. During this talk I will give an overview of some recent developments including what I have been working on, what some of the current pitfalls are, and what may be needed to precisely reconstruct oxygen concentrations in sea water.
Jeroen Groeneveld is a marine geologist at the Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany. He mainly works on the development and application of Mg/Ca (palaeo-thermometry) and other trace metal/Ca ratios (e.g. Mn/Ca, Ba/Ca, B/Ca) as proxies to reconstruct past changes in water column/bottom conditions (e.g. temperature, salinity, oxygen content) on planktic and benthic foraminifera including geochemical signatures in single foraminifera.