Research
To achieve a meaningful comprehension of the biogeochemical relevance of land-water connections, I have worked in different ecosystems, biomes, and institutions. Using a cross-disciplinary approach, grounded in the fields of hydrology, biogeochemistry, and ecology, my research focuses on six major land-water connections:
1. Landscape Features
The chemical composition of the water flowing through streams is intimately linked to the landscapes they drain. Climate, vegetation type or human settlements determine the quality of the water entering streams as well as the microbial processes occurring in them. Yet, our knowledge on how future changes in landscape configuration associated with global change will affect the functionality of running waters is still far from complete.
My research combines both in-situ empirical experiments and large collaborative initiatives (projects DOMINOS, DOMIPEX, AGRHYDROM) to understand how changes in land cover or climate affect the chemistry and functionality of freshwater ecosystems.
I am also interested in how anthropogenic activities impact the functionality of rivers by modifying its natural metabolic regimes; and how streams can be used as natural treatments for diminishing excess nutrient pollution (projects ECOREACTOR, P-REMOVAL, URBIFUN).
2. Watershed Hydrology
Floods and droughts are widespread phenomena, and are expected to become more common in the forthcoming years due to climate change. The consequences of these extreme hydrological events for the health of running waters warrant attention, especially in those regions that are highly vulnerable to global change and its related pressing environmental and socio-economical issues.
My research focuses on assessing how floods and droughts impact key instream biogeochemical processes, including metabolic pathways, nutrient retention and greenhouse gas emissions (projects HIFREQ, DRYFLUX II). In these efforts, I use different approaches such as rainfall-runoff models, high-frequency sensors, and mass balances.
My hypothesis is that the amount of water flowing through watersheds has significant consequences on stream biogeochemistry because it regulates the transfer of matter from lands to streams, but also the capacity of stream biota to act upon it.
3. Riparian Zones
Riparian zones are the natural ecosystems flanking streams and lakes, and constitute unique ecotones between terrestrial and aquatic environments. Although these zones represent only 1.4% of the world surface, they provide several services, including the regulation of energy and nutrient fluxes between lands and streams.
My research focuses on understanding how riparian zones can regulate stream flow and nutrient dynamics at different spatial and temporal scales (projects MONTES, MEDFORESTREAM, MEDSOUL). By combining approaches from the fields of soil sciences, forestry and freshwater ecology, my studies have shown that Mediterranean riparian soils are important sources of nitrogen to streams. My work has further revealed that riparian trees greatly influence stream nutrient dynamics by regulating the amount of light, water and organic matter that enters to streams.
4. Groundwater & Zero-order Streams
Groundwater inflows are major sources of water, carbon and nutrients to streams. As such, groundwater inflows can control rivers’ functionality by acting as a direct source of solutes and by supplying limiting resources that fuel aquatic metabolism. Yet, most empirical and modelling approaches in freshwater sciences do not consider groundwater inflows, as neither do the vast majority of monitoring programs. As a result, a general mechanistic understanding on how groundwater inflows affect catchment fluxes remains elusive.
My research combine regular samplings on groundwater and stream chemistry, in-situ experiments, and a variety of models to assess the mechanisms by which groundwater inflows affect biogeochemical fluxes at catchment scale (projects MONTES, CANTERA).
Recently, I have broadened the scope of my research to study the influence of subsurface flow paths (or discrete riparian input points, DRIPS) on stream biogeochemistry (project SITES). These discrete flow paths are widespread in many landscapes, but their role as regulators of stream biogeochemistry is still unknown.
