Budgeting Oxygen Generation under Changing Light Conditions in Oligotrophic Waters (O2-GLOW)
In order to understand metabolic responses of lake ecosystems to rapid environmental changes like browning, detailed quantification of primary production and respiration under natural conditions is indispensable. However, daytime respiration is 'invisible' to traditional concentration measurements. Thus, our procedural understanding and qualities of predictions are limited.
Stable isotope measurements of oxygen and carbon may offer a tool to investigate functional relationships during the daytime. We propose to use high-frequency in situ measurements together with long-term ecosystem research, and stable isotopes to evaluate the light dependencies of natural phytoplankton communities in different lakes throughout Europe.
Harnessing the synergetic power of these different methodologies, we will gather information on the relationship between lake metabolism and community composition, including unbiased estimates on daytime respiration. Our approach will also provide knowledge on light-induced variability in photosynthetic quotients and the potential effects of high-light conditions on Gross and net ecosystem production.
In general, these investigations will further our understanding of oligotrophic and clear lake ecosystem metabolism and provide a solid foundation for exploring fundamental questions in lake ecology, including browning.