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«My focus is on greenhouse gases»

Katrin Kohnert with her custom-made chamber to capture greenhouse gases and a portable gas analyser on her back for immediate measurements. © Martina Bauchrowitz, IGB

My interest in climate change was already well developed as a bachelor student of geoecology at the University of Bayreuth. Therefore, it was only logical for me to enrol in the Global Change Ecology Master programme at Bayreuth, which addresses both mechanisms of environmental change and climate policy. Later I was able to deepen my knowledge during a doctoral thesis at the GFZ German Research Centre for Geosciences in Potsdam where I investigated how much greenhouse gas is emitted by permafrost regions in the Arctic, which are thawing at an accelerated rate due to climate change. Since January 2019 I have been working as a postdoctoral researcher in the CONNECT project at IGB. Here, I am responsible for measuring emissions of greenhouse gases: carbon dioxide (CO2) and methane (CH4), which is 28 times more climate-effective over a 100 year period.

 

The aim of the CONNECT project is to determine how lake chains behave: Whether signals such as algal blooms propagate from one lake to the next and whether loosely connected lakes respond differently than strongly connected systems. We are exploring these questions in a large-scale enclosure experiment at the IGB LakeLab.

 

I apply several techniques for my analyses. In particular, I use a custom-made chamber that is placed on the water surface to capture greenhouse gases escaping from the lakes and directly measure the emissons in the field with an attached gas analyzer. I also determine greenhouse gas concentrations with a so-called eddy covariance tower installed at the LakeLab with help by colleagues at GFZ Potsdam. The tower monitors greenhouse gases at slightly higher altitudes about 2.5 metres above the water surface and within a radius of approx. 200 metres at Lake Stechlin. Finally, to elucidate how the exchange of greenhouse gases between the water surface and the atmosphere behaves over a large area, and including the tereestrial lake environment, we also work with a research aircraft operated by the Freie Universität Berlin. This is an important part of the CONNECT project because in addition to the LakeLab experiment, we monitor 20 lakes in Mecklenburg-Western Pomerania and Brandenburg, including Lake Stechlinsee. The aircraft scanned our study area at an altitude of 150 meters a.s.l. first in August 2019. Taken together, these data help us to determine whether lakes act as carbon sinks or sources under changed environmental conditions. Our first results suggest that they will release more methane into the atmosphere when climate change proceeds, thus further driving climate change.

Katrin Kohnert

is a geoecologist by training and has been employed as a postdoctoral researcher at IGB Stechlin in the CONNECT project since January 2019.

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