MAÏTURIK

MAÏTURIK (Greenhouse gas dynamics in lakes Maï Ndombé and Tumba and the Ruki and Ikelemba rivers) is a FRS-FNRS funded credit (CDR, 2021-2022).

This project is motivated by the fact that CO2 and CH4 emissions from inland waters (rivers, lakes and reservoirs) are probably very significant for global budgets of these two potent greenhouse gases, and are disproportionality much more intense in tropical areas, although dramatically under-sampled, especially in the African continent.

The goal of this project is to study the CO2 and CH4 emissions to the atmosphere from two large lakes (Tumba and Mai Ndombe) and two large rivers (Ikelemba and Ruki) that drain the “Cuvette Centrale Congolaise”, a giant wetland complex (with a flooded area the size of Germany) situated in the core of the Congo River basin, the second largest river on Earth in terms of freshwater discharge and of catchment area. Due to a strong connectivity with wetlands, lakes Tumba and Mai Ndombé and Ikelemba and Ruki Rivers should be characterized by high dissolved organic matter concentrations with high humicity that will on the one hand limit light penetration in the water and aquatic phytoplankton primary production and on the other hand sustain bacterial respiration.

Both processes should promote high CO2 aquatic concentrations and CO2 emissions to the atmosphere. The shallowness of the rivers and lakes and large organic matter inputs from the wetlands should also promote the production of CH4 and its emission to the atmosphere. We will investigate CH4 sedimentary production, CH4 bacterial oxidation in the water column and diffusive and ebullitive emissions of CH4 to the atmosphere.