LAVIGAS

LAVIGAS (Lake Victoria grenhouse gas dynamics) is a FRS-FNRS funded project (PDR, 2018-2019).

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nland waters (streams, rivers, lakes and reservoirs) are important players in the global budgets of long-lived green-house gases (GHGs), acting as vigorous sources to the atmosphere of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide _(N2O). Available data suggest that CH4 emissions from inland waters are highest at tropical latitudes although these are also the regions where data are dramatically scarce and urgently needed to improve accuracy of emission estimates. Available data suggest that CO₂ emissions from rivers in tropical latitudes could also be higher than their temperate counterparts. However, tropical lakes could be sinks of atmospheric CO₂, which would shift the paradigm that lakes are sources of CO₂ to the atmosphere based on data-sets acquired at high- and midlatitudes. The main goal of the LAVIGAS project is to fill an enormous data gap by acquiring a seasonally and spatially resolved data-set of CO₂, CH4 and N₂O dissolved concentrations in Lake Victoria, the largest lake in the tropics and second largest in the World, where to our best knowledge no data are available on the dissolved concentration of these GHGs. The data-set will allow to compute the GHG fluxes with the atmosphere, and the analysis with ancillary data (O₂, nutrients, phytoplankton pigments, organic matter concentration and stable isotopic composition) will also allow to decipher the biogeochemical processes that control the temporal variability and the spatial distribution of these GHGs. Data will also be analysed with data-sets that are methodologically consistent obtained by our group in other African lakes (Kivu, George, Edward). The project builds on a successful on-going collaboration with the National Fisheries Resources Research Institute (NaFIRRI) on Lake Edward (BELSPO project HIPE), providing a unique opportunity for our group to sample a remote and large tropical lake for the first time regarding the distribution of GHGs.