M-TROPICS is one of the 21 CZOs part of OZCAR, the French network of environmental observatories aiming at monitoring the various compartments of the critical zone over the long term. The position paper of OZCAR has been published in Vadose Zone Journal and is available here (open access).
Headwaters are hotspots of carbon dioxide (CO2) evasion from rivers. While emerging evidence suggests that groundwater contributes disproportionately to CO2 in headwater streams, the processes of CO2 delivery to streams and subsequent evasion to the atmosphere remain largely unknown. This study, partly based on CO2 measurements along the Houay Pano stream in Northern Laos (M-TROPICS/MSEC), […]
Groundwater contribution to streamflow sustains biodiversity and enhances ecosystem services, especially under monsoon-driven climate where stream baseflow is often the only available water resource during the dry season. This study assessed how land use change influences streamflow and its groundwater contribution in the small headwater catchment of Houay Pano (M-TROPICS/MSEC) in the lower Mekong basin, […]
Land use change from annual crops to commercial tree plantations can modify flow and transport processes at the watershed scale, including the fate and transport of fecal indicator bacteria (FIB), such as Escherichia coli. The objective of this study was to provide a comprehensive assessment of the impact of land use change on microbial transfer […]
High rainfall intensities on slopes produce runoff and erosion, but seeds are also carried down slope into streams by surface wash, causing weed infestation in lower parts of a river system. This interdisciplinary study was performed in the Houay Pano catchment (M-TROPICS/MSEC in Laos), farmed by smallholders and equipped with eight gauging stations. Main findings […]
An inter-disciplinary team at Bengaluru’s Indian Institute of Science (IISc) studied how different tree species partition underground water resources up to 30m depth and co-existing tree species diverge in water uptake depths (M-TROPICS/BVET). Deep rooted trees turn to be more vulnerable to severe droughts than shallow rooted species : climate change-type droughts could then affect […]
The analyses of silicon isotopes in soil, water and plant compartments of the Mule Hole forested watershed (M-TROPICS/BVET) reveal that vegetation takes up twice more silica than first estimates using elemental mass balance. This flux is 30 times higher than the solute silica flux exported by the stream, itself resulting principally from litter decay. The […]
This study (M-TROPICS/BVET) identified and quantified the Si sources to rice plants using a solute mass balance at soil-plant scale and the silicon isotopic signatures of the various Si pools. It reveals that the main Si sources are soil amorphous silica, irrigation water and to a lesser extent Si fertilizer when it was applied. In […]
In montane Southeast Asia, deforestation and unsuitable combinations of crops and agricultural practices degrade soils at an unprecedented rate. Typically, smallholder farmers gain income from “available” land by replacing fallow or secondary forest by perennial crops. The aim of this study (M-TROPICS/MSEC) was to understand how these practices increase or reduce soil erosion. The paper […]