MULTI-DECADAL INCREASE IN ALGAL ORGANIC MATTER PRODUCTION IN TROPICAL LAKES ACROSS CENTRAL MEXICO

Global changes have a strong influence on lake algal communities and the major biogeochemical cycles that they shape. Growing evidence illustrates unprecedented algal community reorganizations and disruptions to lake carbon and nutrient cycles over past decades driven by myriad global and local human stressors; however, comparably little is known of such transitions at lower latitudes. We explored patterns and drivers of algal organic matter production and related biogeochemical cycles in five tropical crater lakes spanning central Mexico. To overcome long-term data limitations, we utilized information preserved in dated lake sediments, employing an array of biogeochemical and ecological indices tracking changes in algal production and community dynamics, and overall ecosystem state, over the past century. In two lakes, we extended our analysis further back in time to assess how ecosystem changes driven by major climate transitions of the past millennium compare with those of recent decades. Preliminary results indicate a distinct increase in algal organic matter production in recent decades across the region, and an enhanced carbon sink in the sediments of some of the lakes. These changes appear to be linked to increased evaporative forcing on lake levels as well as to local watershed disturbances. Our results further depict a similar period of increased organic matter production coincident with an earlier warm period; however, the pace and nature of the recent changes appear unparalleled.

Primary Presenter: Marttiina Rantala, University of Liège (marttiina.rantala@gmail.com)

Authors:

Marttiina Rantala, University of Liège  (marttiina.rantala@gmail.com)

Isabel Israde-Alcántara, Universidad Michoacana de San Nicolás de Hidalgo  (isabelisrade@gmail.com)

Reza Safaierad, University of Liège  (safaierad.reza@gmail.com)

John Smol, Queen’s University  (smolj@queensu.ca)

Carsten Meyer-Jacob, Université du Québec en Abitibi-Témiscamingue  (Carsten.Meyer-Jacob@uqat.ca)

Christopher Grooms, Queen’s University  (groomsc@queensu.ca)

Wojciech Tylmann, University of Gdansk  (wojciech.tylmann@ug.edu.pl)

Pierre Francus, INRS Centre Eau Terre Environnement  (Pierre.Francus@inrs.ca)

Gilles Lepoint, University of Liège  (g.lepoint@uliege.be)

Nadine Mattielli, Université libre de Bruxelles  (Nadine.Mattielli@ulb.be)

Sarah Metcalfe, University of Nottingham  (sarah.metcalfe@nottingham.ac.uk)

Nathalie Fagel, University of Liège  (nathalie.fagel@uliege.be)