Low N2O and variable CH4 fluxes from tropical forest soils of the Congo Basin
Matti Barthel, Marijn Bauters, Simon Baumgartner, Travis W. Drake, Nivens Mokwele Bey, Glenn Bush, Pascal Boeckx, Clement Ikene Botefa, Nathanaël Dériaz, Gode Lompoko Ekamba, Nora Gallarotti, Faustin M. Mbayu, John Kalume Mugula, Isaac Ahanamungu Makelele, Christian Ekamba Mbongo, Joachim Mohn, Joseph Zambo Mandea, Davin Mata Mpambi, Landry Cizungu Ntaboba, Montfort Bagalwa Rukeza, Robert G. M. Spencer, Laura Summerauer, Bernard Vanlauwe, Kristof Van Oost, Benjamin Wolf, Johan Six
Abstract
Abstract Globally, tropical forests are assumed to be an important source of atmospheric nitrous oxide (N 2 O) and sink for methane (CH 4 ). Yet, although the Congo Basin comprises the second largest tropical forest and is considered the most pristine large basin left on Earth, in situ N 2 O and CH 4 flux measurements are scarce. Here, we provide multi-year data derived from on-ground soil flux ( n = 1558) and riverine dissolved gas concentration ( n = 332) measurements spanning montane, swamp, and lowland forests. Each forest type core monitoring site was sampled at least for one hydrological year between 2016 - 2020 at a frequency of 7-14 days. We estimate a terrestrial CH 4 uptake (in kg CH 4 -C ha −1 yr −1 ) for montane (−4.28) and lowland forests (−3.52) and a massive CH 4 release from swamp forests (non-inundated 2.68; inundated 341). All investigated forest types were a N 2 O source (except for inundated swamp forest) with 0.93, 1.56, 3.5, and −0.19 kg N 2 O-N ha −1 yr −1 for montane, lowland, non-inundated swamp, and inundated swamp forests, respectively.