Regarded as a persistent source of carbon to the atmosphere, high latitude lakes can also represent an important sink for atmospheric CO2. In fact, these lakes are likely alternating between being CO2 sources and sinks depending on the timing and magnitude of OM inputs, catchment characteristics and biogeochemical/hydrodynamic connectivity between surface and bottom. There is, however, uncertainly regarding the contribution to the CO2 flux from temporal effects in the metabolic balance of Arctic and sub-Arctic lakes hence the importance of these lakes in the global carbon system is poorly resolved.
To address this research gap, we will collect CO2 and DIC concentration and isotopic profiles to constrain metabolic effects during transition from winter to summer conditions. We will estiamte the gross primary production, community respiration and net ecosystem production at a daily scales as well as assess the inputs related to snowmelt and precipitation at Lake Revvatnet (Svalbard). The coupled CO2/O2/pH measurements and hydrodynamic datasets will be processed by the Polish-Norwegian research team. Field results will be complemented with modelling of the water column hydrodynamics to evaluate CO2 transport and evasion using a state-of-the-art hydrodynamic model.
The goal is to improve our understanding of the temporal variability in the metabolism of Arctic and sub-Arctic lakes. This goal will be reached by integrating field results into a simplified lake metabolism model that allows quantification of the relative importance of various processes related to lake CO2 fluxes. In addition, this project also aims to strengthen the collaborative (Polish-Norwegian) work on Arctic lake research and allows us to prepare a larger grant application aiming to monitor changes in carbon metabolism related to ongoing climate-driven limnological and near-lake landscape effects in the Arctic (Svalbard), subarctic (Norway) and in Alpine lakes (Norway and Switzerland).