Freshwater lakes play a vital role in the global carbon cycle, acting as both a source of greenhouse gases (GHG) such as CO₂ and CH₄ as well as a carbon sink through burial processes in their sediments. While the role of lakes in the carbon cycle has received quite some scientific attention, little is known about the drivers behind the balance of carbon storage and GHG emissions in these ecosystems. Lakes exhibit resilience to pressures like eutrophication, and exceeding their resilience capacity will lead to a shift in ecosystem state. This is displayed, especially in shallow lakes, as a shift from a clear, plant-dominated state to a turbid phytoplankton-dominated state. In this work, we evaluate how lake resilience to eutrophication is linked to lake carbon cycling. To this end, we expanded the existing ecosystem model PCLake⁺ with carbon-related processes: GHG emissions and carbon burial. PCLake⁺ is an open source lake model that explicitly models ecological processes (biotic and abiotic interactions) within the general framework of resilience assessment. It has been used extensively in both research and water management. We hypothesized that GHG emissions are minimized, and carbon storage potential is maximized in a clear ecosystem state, whereas GHG emissions (in particular CH₄) would be enhanced in a turbid ecosystem state. Through our model expansion we study net carbon storage and emission along a gradient of eutrophication, expanding the focus of water management from improvements on water quality towards inclusion of carbon storage potential.

Primary Presenter: Mandy Velthuis, Radboud University (mandy.velthuis@ru.nl)

Authors:

Mandy Velthuis, Radboud University  (mandy.velthuis@ru.nl)

Annette Janssen, Wageningen University  (annette.janssen@wur.nl)

Yike Li, Netherlands Institute of Ecology  (y.li@nioo.knaw.nl)

Sarian Kosten, Radboud University  (sarian.kosten@ru.nl)

Tineke Troost, Deltares  (tineke.troost@deltares.nl)

Qing Zhan, Netherlands Institute of Ecology  (q.zhan@nioo.knaw.nl)

Sven Teurlincx, Netherlands Institute of Ecology  (s.teurlincx@nioo.knaw.nl)