Conferences - Seminars
EESS talk on "The Great Melting: How Small Living Things Affect Global Processes"
By Dr Liane Benning, professor in Interface Geochemistry, Free University Berlin and German Research Center for Geosciences (GFZ) Potsdam; DE
Research we do focusses on biogeochemical element cycling in in Earth surface environments with special emphasis on mineral-fluid-microbe interface reactions. We combine experimental and field observations and assess mineral formation or breakdown reactions via in situ and time resolved electron and X-ray approaches or assess the role of ‘life' in extreme environments using various ‘omic’ techniques.
Anthropogenically enhanced melting of snow and ice in polar regions and the associated sea level rise are controlled by changes in albedo. On land and on the Greenland Ice Sheet (GrIS) in particular, such changes are primarily a consequence of increased delivery of light absorbing impurities (LAI) as they accelerate melting. So far only wind delivered industrially produced or wild fire derived black carbon (soot) or mineral dust are considered in global climate models. We recently demonstrated the importance and role of pigmented snow and ice algae in changing albedo in the Arctic [1,2] and are now working on a multidisciplinary project to isolate the microbial contribution (bio-albedo) from the other albedo-affecting impurities. I will introduce our results about diversity, function and metabolic activity of snow and ice algae and their link to geochemical variability from a Pan Arctic study, and contrast these with recent results from the GrIS where we quantify both biological and non-biological LAI particulates and show that the close interactions between microbes, soot and minerals in highly dynamic snow-ice transition zones play the crucial role in enhancing melting. Finally, I will show how we upscale the ground based findings through satellite data and ice sheet wide modelling. As climate warms, the biologically driven processes will increasingly contribute to the darkening of the GrIS, and the subsequent acceleration of the melting of the GrIS ice masses, yet these separate effects are currently not included in predictive global numerical models. With our work and we aim to change this over the next few years so that we can better understand how water-mineral-microbe interface reactions at the molecular scale affect such large scale processes.
Organization EESS - IIE
Accessibility General public
This event is internal