Many lakes in the World, particularly from endorheic basins in arid and semi-arid areas, are shrinking. This implies that the sedimentary carbon sink, sometimes the result of thousands of years of burial, may be prone to remobilization once the accumulated organic matter is exposed to atmospheric oxygen. To test this hypothesis, we have visited the endorheic lake Laguna de Gallocanta in Spain, and the largest vanishing lake on Earth, the Aral Sea in Kazakhstan. Applying a time for space substitution approach, we investigate if the organic carbon content of the sediments follows a chronosequence of drying, whether carbon emissions are actually happening in those sediments, and which organic carbon fractions are being remobilized. We put our results in the greater context of the potential implications of emissions from those emerged sediments for the global carbon cycle, and also discuss the potential role of recovering those lakes as a mitigation action against climate change compared to other customary mitigation alternatives.

Primary Presenter: Rafael Marcé, Catalan Institute for Water Research (ICRA) (rmarce@icra.cat)

Authors:

Daniel Díaz de Quijano, ICRA  (ddiazdequijano@icra.cat)

Lorena Cojoc, ICRA  (lcojoc@icra.cat)

Enrique Moreno-Ostos, University of Malaga  (quique@uma.es)

Sofía Rodríguez, University of Málaga  (sofiarg@uma.es)

Anna Freixa, ICRA  (afreixa@icra.cat)

Jorge Montes-Pérez, University of Málaga  (jmontesp@uma.es)

Biel Obrador, University of Barcelona  (obrador@ub.edu)

Daniel von Schiller, University of Barcelona  (d.vonschiller@ub.edu)

Núria Catalán, IDAEA-CSIC  (ncatalangarcia@gmail.com)