An international research team, including researchers from the CSIC (CEAB and IDAEA) and the UIB, is studying the effects of increased salinity in the waters of the Gambia River. The project is pioneering due to its interdisciplinary perspective, evaluating both the ecological and socioeconomic effects of this growing global issue.

Freshwater salinization has severe consequences for ecosystems (such as biodiversity loss or changes in the carbon cycle) and people (lack of drinking water, health issues, or impacts on livelihoods, including agriculture, fishing, or mollusk harvesting). One of the areas in the world where it is causing the most damage is the Gambia River (West Africa), which is experiencing a significant increase in salinity due to a prolonged drought, a situation expected to worsen with rising sea levels and the construction of a massive dam that would drastically reduce its flow.

For the first time, a research team is studying the salinization of this river and its impacts. They have started identifying, quantifying, and describing its consequences on key aspects such as changes in aquatic biodiversity, impacts on greenhouse gas emissions, the effects on mangrove areas, and consequences for people. The team includes experts in diverse fields — such as biogeochemistry, biology, ecology, geology, and social sciences — from research centers and universities in Africa, Australia, and Europe. Among them are researchers from the Institute of Environmental Assessment and Water Research (IDAEA-CSIC), the Blanes Center for Advanced Studies (CEAB-CSIC), and the University of the Balearic Islands (UIB).

Núria Catalán, a CEAB-CSIC researcher and team member, explains: “We aim to understand both the changes in processes occurring within the river and its natural environment due to the increasing salinity of its waters, as well as the impacts on the local communities that depend on it.”

The research seeks not only to understand the effects of rising salinity in this African river but also to obtain a broader perspective on what is happening globally with the issue of freshwater salinization. As Miguel Cañedo-Argüelles, an IDAEA-CSIC researcher, explains, “It is a global problem that is increasing due to the combined effects of climate change and the growing demand for resources.” The project aims to gather evidence that can help develop strategies applicable anywhere this situation occurs. One of the objectives is to ensure that the proposed solutions are co-created with local populations.

The team emphasizes that the results of the research project (called SALBIA) should serve at the local level, contributing to improved management of the Gambia River, and at the global level, providing a model for addressing salinization issues in other regions. “We hope this work will provide useful tools for the sustainable management of aquatic ecosystems in areas vulnerable to salinization and help co-design possible ways to adapt to this impact,” state Pablo Rodríguez Lozano, a researcher at UIB, and Miguel Cañedo-Argüelles, from IDAEA-CSIC.

Preliminary results

Preliminary results from the first sampling campaign, conducted in the summer, indicate that salinity is altering the biodiversity patterns of the river. Communities of organisms have been found to vary significantly along the salinity gradient.

Salinity is also affecting the movement and transformation of carbon within the river, influencing greenhouse gas emissions such as CO2 from the water and sediments. It has been observed that in saltier areas, especially in the lower reaches, greenhouse gas emissions are higher.

A second sampling campaign is planned for early 2025 to continue gathering information on the environmental and socioeconomic effects of freshwater salinization.

The SALBIA project: An interdisciplinary approach

 This research project is structured around three sub-projects analyzing the impacts of salinization from different perspectives:

• BIO, which evaluates the effects on aquatic biodiversity and ecosystems. This includes studying how salinization affects the current and past distribution of species by combining DNA analysis with traditional ecological knowledge (e.g., from fishers).
• GEO, focusing on the impact of salinization on the carbon cycle and the emissions of greenhouse gases, such as CO2 and CH4, from the river’s waters and mangrove sediments.
• SOC, dedicated to assessing the effects of salinization on local communities; identifying how ecosystem changes impact community well-being and livelihoods; and evaluating the adaptation strategies that local communities are implementing.

The sub-projects work closely together to understand how salinization affects not only the natural environment but also the people who rely on the river for their livelihoods while proposing solutions applicable globally.

International collaboration

 SALBIA is a coordinated project co-financed by the European Union, the Spanish Ministry of Science, Innovation and Universities, and the Spanish State Research Agency as part of the 2022 Knowledge Generation Call. It also develops in close collaboration with local stakeholders, such as the Great Institute, the University of the Gambia, the Sankandi Youth Association, and the Gambian Ministries of Climate Change and Fisheries, as well as international partners such as the University of Tasmania, the Institute of Research for Development (France), the University of Landau (Germany), the University of Geneva (Switzerland), and LSCE-CNRS (France), among others.