Zaragoza, May 31 (EFE).- An investigation by the Pyrenean Institute of Ecology (IPE), a center belonging to the Higher Council for Scientific Research (CSIC), has confirmed an exponential increase in the contribution of sediments and the accumulation of organic carbon in the lakes Pyrenees from 1950, which is related to changes in the seasonality of rainfall and greater productivity of algae due to increased temperatures.
The study was carried out by means of a sampling carried out in six high mountain lakes located between 1,870 and 2,630 meters of altitude in the western and central Pyrenees of Spain to evaluate the regional response to current global change in the Mediterranean mountains of high altitude, results that have just been published in the academic journal Scientific Reports, informs the IPE in a press release.
As explained by Alejandra Vicente, a researcher at the IPE and the first signatory of the article, the greatest changes during the last millennium in the contribution of sediments and the accumulation of organic carbon occurred, in all cases, from 1850 and 1950 of our era.
An increase in flows that the researcher relates to the fall of more winter rain than snow, “and the consequent greater eroding potential of runoff,” explains Vicente de Vera.
According to the results obtained, the researcher points out that, before the 20th century, there were also phases with high sediment flows to the Pyrenean lakes during periods of greater human pressure, such as the Middle Ages, and during some more humid phases of the Little Ice Age (14th to 19th centuries), but with greater variability between lakes.
The recent increase in the accumulation of organic matter and the changes in the associations of diatom algae would be due to the greater productivity of the lakes, caused by the increase in temperatures and the increase in the contributions of nutrients by atmospheric deposition.
Recent trends in sediment and carbon fluxes demonstrate the rapidly increasing human impact and global warming, which has affected not only the ecological dynamics of alpine lakes but also the hydrological cycle of mountain basins.
Although sediment fluxes were high in other previous periods, recent values are always the highest and in the case of organic carbon the increases are particularly high in recent decades, these sources report.
The work is part of the research in the REPLIM network in which the impacts of climate variability and human activities are monitored (geoportal of the Pyrenean Observatory of Climate Change, OPCC: https://opcc-ctp.org/es/geoportal ).
The team includes research staff from the Geological and Mining Institute (IGME-CSIC), the University of Salamanca, the University of Valencia, the Marine Research Institute (IIM-CSIC), CREAF and the Pontifical Catholic University of Chile.