Multiscale TROPical CatchmentS (M-TROPICS)

Experimental Tropical Watersheds

M-TROPICS Critical Zone Observatories

The CZO Multiscale TROPIcal CatchmentS (M-TROPICS) provides the international scientific community with unique decennial time series of meteorological, hydrological, geochemical, and ecological variables in tropical environments. The CZO M-TROPICS involves academic and governmental partners in tropical countries (Cameroun, India, Lao PDR, and Vietnam) and is included in the Research Infrastructure OZCAR, the French contribution to the international CZO initiative.

Objectives

  • Long-term monitoring of the variables needed for establishing water, biogeochemical (including particulate matter), and energy budgets: water and inorganic and organic matter in solution (major anions and cations, carbon), in suspension (suspended particulate matter, including organic carbon), and bed particulate matter
  • Impact assessment of global change (land-use, climate) on water fluxes, chemical weathering, and physical erosion
  • Data and information dissemination to the scientific and stakeholder communities
  • Capacity building in the field of catchment hydrology and soil erosion, through on-the-job training, teaching, and student internships, and basic geochemistry through analytical platforms
  • Recommendations on land use policy to the national authorities

Strengths

  • Multiscale approach, both spatially (from microplot to catchment and larger river basins scales) and temporally (from sub-hourly to multi-decennial time-series)
  • Multidisciplinary approach, currently involving hydrology, biogeochemistry, soil science, agronomy, ecology, remote sensing, experimentation, and modelling

Achievements

Besides data collection and dissemination, the achievements of M-TROPICS on June 2021 are:

  • 241 scientific publications in international journals
  • 32 scientific publications in national journals
  • 1 special issue in the Lao Journal of Agriculture and Forestry (2008): Management of soil erosion and water resources in the uplands of Lao P.D.R., by Ribolzi O. (Ed.), Pierret A. (Ed.), Gebbie L. (Ed.), Sengtaheuanghoung O. (Ed.), and Chanphengxay M. (Pref.)
  • 57 PhDs, 7 post-docs, and 281 MSc, BSc and Agric. Eng. degrees

Rationale

Hand pump well, Berambadi catchment.

The Earth Critical Zone (CZ) is defined as the thin layer between the top of the canopy and the bottom of groundwater aquifer in which complex interactions involving rock, soil water, air and living organisms regulate the natural habitat and determine the availability of life sustaining resources. This concept brings together scientific disciplines in the aim to tackle crucial environmental issues regarding how the various components of the CZ react to global changes, including land use and climate changes:

  • What are the water, solute, and particulate fluxes exported from tropical catchments?
  • What is the impact of rapid land use changes on hydrology, water quality, soil resources?

The strategies adopted to answer these questions are often integrated approaches on experimental catchments, where hydrological, sedimentary, biogeochemical and ecological studies can be coupled. Acquiring simultaneous time series of meteorological, hydrological, geochemical, and ecological data over decades on river systems (both small experimental watersheds and larger basins) representative of the diversity of ecosystems is pivotal for the understanding of these processes, building integrated modelling and for proposing predictive scenarios.

Houay Pano catchment.

Among the Critical Zone Observatories (CZOs) that have been implemented by the Earth Science community in the past 30 years, very few were set up in the Tropics despite the huge importance of these regions in terms of population density, fast-changing land use, biodiversity hotspots, biomass stock on continents (humid forests), size of river systems. In addition, rainfall in the Tropics is mostly governed by monsoon systems, which are particularly sensitive to climate change.

Missions

Field campaign in Cameroon to study biogeochemical cycles and weathering in a tropical context

On September 19-25, Jean Riotte, Christelle Lagane, and Jean-Jacques Braun from GET/IRD participated to a field campaign at the Nsimi experimental watershed, monitored within the M-TROPICS CZO. Recently, the land use in Nsimi watershed has been changed to agriculture mixed with residual forest and fallow. The objective of the mission was thus to start the […]

Conferences

M-TROPICS catchments introduced at the Cyberseminar Series of CUAHSI: “Introduction to critical zone observatories and watershed sites”

Muddu Sekhar (IISc Bengalore, CEFIRSE) and Laurie Boithias (GET) presented the key questions and findings from the two experimental catchments Berambadi (India) and Houay Pano (Lao PDR) at the Cyberseminar Series of CUAHSI: “Introduction to critical zone observatories and watershed sites” on Sept. 7. The introduction of the Berambadi catchment was focused on the effect […]

Events

Renewal of the Memorandum of Understanding with DALaM in Lao PDR

On 9th of August 2021, Dr Nivong Sipaseuth, Director General of the Department of Agricultural Land Management (DALaM) of the Laotian Ministry of Agriculture and Forestry and Dr Eric Deharo, Representative of IRD in Laos signed the renewal of an agreement of scientific and technical cooperation between the two institutions. The signature of this agreement confirms […]

Articles

Agricultural groundwater with high nitrates and dissolved salts given to pregnant mice alters brain development in the offspring

This new paper, at the interface between environment and health, shows that groundwater contaminated by agricultural inputs from the Indian site of Berambadi (M-TROPICS observatory), significantly impacts the brain development of mice when given to pregnant or lactating mice: fewer neurons, fewer astrocytes (white blood cells in the brain), and more dead cells in the […]

Articles

Decay Rate of Escherichia coli in a Mountainous Tropical Headwater Wetland

Fecal indicator bacteria like Escherichia coli (E. coli) are widely used to assess water contamination, but their behavior in tropical ecosystems is poorly documented. The main objectives of this study led by Paty Nakhle, PhD student at GET in collaboration with iEES Paris, were to: (i) evaluate decay rates (k) of the total, particle-attached and […]

Articles

The M-TROPICS CZO releases long-term meteorological, hydrological, sedimentary geochemical, and land use datasets in Cameroon, Lao PDR, and India

The CZO M-TROPICS (Multiscale TROPIcal CatchmentS) investigates the response of tropical catchments to global change based on long-term collection of meteorological, hydrological, sedimentary, geochemical, and land use data in partnership with academic and governmental institutions in various tropical countries. M-TROPICS includes in particular the experimental watersheds of Nyong in Cameroon (1994-), Houay Pano in Lao […]

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