Messengers from the past
One of the greatest marine environmental challenges today is deoxygenation, which means decreasing concentrations of dissolved oxygen in the world’s oceans. This is caused especially by warming, increased water stratification, and coastal eutrophication. Today’s marine environmental changes have created a need to understand their severity and what effects there could be.
-There are marine geological records that tell us a lot about how marine environments work in different conditions, but to understand more we need improved techniques to read the natural records, or so called proxies, to reconstruct past seawater oxygen, says Professor Helena Filipsson, Department of Geology at Lund University.
The project focuses on expanding proxies for deoxygenation in marine bottom waters. There are small organisms, calcite protists (foraminifera), that carries information about oxygen levels in the past. By analyzing sets of field collected surface sediment samples from two low-oxygen regions in the North East Atlantic and North East Pacific through microanalytical techniques, including synchrotron X-ray methods, this information can be deciphered. Syncrothron light based methods can be compared with a very strong microscope where xrays are used to study elemental composition. The researchers will also study living foraminifera in mesocosm studies and genetically characterize foraminifera samples to minimize effects of taxonomic uncertainty.
- Improved bottom water oxygen reconstructions and uncertainty estimates will help us to better understand the marine ecosystem sensitivity, and support evidence-based environmental management strategies.
Read also the Havsutsikt article about Foraminifera as storytellers (in Swedish)