Quantification and regulation of carbon fluxes in Lake Windsborn (Eifel): do hot spots and hot moments of carbon cycling occur in shallow waters?

Basic data for this project

Description

Recently it has been discovered that small aquatic ecosystems cover much larger areas than previously assumed. Due to this fact and their high metabolic activity, they are most likely significant sinks for carbon and sources of methane and may provide relevant feedback in the climate-biosphere system. The role of these systems is so far poorly understood because they fall between disciplinary boundaries of terrestrial ecosystem science and limnology. To begin rectifying our knowledge deficiency the project will quantify the gas exchange between water and the atmosphere and sediment and surface waters in a shallow dystrophic model system and establish controls on CO2 and CH4 emission and carbon sequestration throughout the year. In this analysis we focus on periods and zones that have great influence on annual balances of carbon, such as ice breakup, spring and fall. To this end most recent advances in the application of sensor systems and high resolution gas flux chamber measurements will be employed that will allow for novel insights in the functioning of the carbon cycle. Carbon fluxes will be related to environmental variables and internal biological and physical dynamics. Moreover, we will focus on methanogenesis, methane oxidation and transport, which are key processes for the greenhouse warming potential of these systems. In this respect, mass balances, pore water analysis and modeling, incubation techniques and application of 13C stable isotope balances are combined to quantify these processes and their dependencies on environmental conditions. The research will thus address an important knowledge deficiency that potentially hampers assessments about climate-biosphere interactions.