GenCon20_Alter-C

Alteration of carbon sinks and sources in shrinking inland waters: ecosystem metabolism (Alter-C)

In many regions of the world, inland waters are shrinking due to the combined effects of climate change, water extraction and other human activities. Sections of river networks that indicate temporary water expand and remain dry longer, lakes and ponds dry up exposing large areas of previously flooded sediments, and the surface area covered by water in reservoirs shrinks or even disappear altogether when the outlets stop working.

These emerged sediments are prone to terrestrialization (growth of ephemeral or permanent vegetation). In addition, reduced water levels and increased water residence time change aquatic metabolism by favoring anaerobic metabolic pathways. At the same time, the geochemistry of the system is affected by the alteration of the water budget, modifying the dynamics of mineral precipitation and dissolution between the water column and the sediments. Consequently, we expect a strong impact of the reduction on the capacity of inland waters to sequester carbon (C) from the atmosphere, a relevant service that these ecosystems provide to humans.

The goal of the Alter-C coordinated project is to understand how sinks and sources of C in continental waters are affected by reduction under present and future conditions. Alter-C combines state-of-the-art methodologies with an integrative perspective, including river networks, lakes, ponds and reservoirs, in an ambitious research program that considers the main drivers of inland water depletion: climate change, l water extraction and the dismantling of dams.