FRIAS Kolloquium - Benjamin Kraemer

Lake dead zones: global drivers and sensitivity to climate change

Dead zones commonly occur at the mouths of polluted rivers, where excessive algal decomposition depletes oxygen, creating conditions inhospitable for most aquatic life. In the world’s oceans, these zones can span thousands of square kilometers and are known to negatively impact ecosystems, fisheries, and coastal communities. However, despite the importance of lakes for drinking water, recreation, and biodiversity, the global distribution, drivers, and impacts of dead zones in lakes remain poorly understood. Here, I present ongoing research using a combination of remote sensing and in situ datasets to document the presence and temporal trends of dead zones in hundreds of the world’s largest lakes over recent decades. The findings reveal that lake dead zones are widespread, occurring across diverse geographic and climatic regions, and are linked to a range of human activities within their watersheds. I also outline my proposed research, which will build on these findings to examine the sensitivity of dead zones to climate change across lakes, rivers, and oceans. Additionally, this work will aim to identify land management strategies that can mitigate the effects of climate change on aquatic dead zones, supporting sustainable management of these critical ecosystems.