| Text | 382530 2017 10.1007/s10452 017 9618 3 Scopus 2 s2.0 85016119951 ISI Web of Science WOS 000400989500009 Benthic food web Early warning signal Global change Oxygen depletion Paleolimnology Regime shift Rising variance and abrupt shifts of subfossil chironomids due to eutrophication in a deep sub alpine lake Belle S.; Baudrot V.; Lami A.; Musazzi S.; Dakos V. UMR CNRS 6249, Laboratoire de Chrono Environnement, Universite de Bourgogne Franche Comte, Besançon, , , France; UMR CNRS 6249, Laboratoire de Chrono Environnement, Universite de Bourgogne Franche Comte, Besançon, , , France; Center for Limnology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartumaa, , Estonia; CNR, Istituto per lo Studio degli Ecosistemi, Verbania, Pallanza, , Italy; Institute of Integrative Biology, Center for Adaptation to a Changing Environment, ETH Zurich, Zurich, , Switzerland; Institut des Sciences de l Evolution de Montpellier ISEM , BioDICee team, CNRS, Universite de Montpellier, Montpellier, , , , France; Institut des Sciences de l Evolution de Montpellier ISEM , BioDICee team, CNRS, Universite de Montpellier, Montpellier, , , , France; Institut des Sciences de l Evolution de Montpellier ISEM , BioDICee team, CNRS, Universite de Montpellier, Montpellier, , , , France In response to anthropogenic eutrophication and global warming, deep water oxygen depletion is expected to have large effects on freshwater lake biogeochemistry and resident communities. In particular, it has been observed that deep water hypoxia may potentially lead to regime shifts of lake benthic communities. We explored such community shifts by reconstructing a high resolution subfossil chironomid record from a sediment core collected in the sub alpine lake Remoray in France. We identified an abrupt shift in chironomid composition triggered by the collapse of the dominant Sergentia coracina type chironomids around 1980. We found that the collapse of Sergentia coracina type was coupled to a gradual increase in organic matter content in lake sediments caused by eutrophication. We concluded that the most probable cause for the collapse of Sergentia coracina type was a change in oxygen concentrations below the minimal threshold for larval growth. We also analyzed trends in variance and autocorrelation of chironomid dynamics to test whether they can be used as early warnings of the Sergentia collapse. We found that variance rose prior to the collapse, but it was marginally significant Kendal rank correlation 0.71, p = 0.05 , whereas autocorrelation increased but insignificantly and less strongly Kendal rank correlation 0.23, p = 0.25 . By combining reconstructions of ecosystem dynamics and environmental drivers, our approach demonstrates how lake sediments may provide insights into the long term dynamics of oxygen in lakes and its impact on aquatic fauna. 51 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 85016119951 partnerID=q2rCbXpz Articolo 2017_Aquat_Ecol_51_307_319.pdf Articolo in rivista Kluwer Academic Publishers 1386 2588 Aquatic ecology Print Aquatic ecology Print Aquat. ecol. Print Aquatic ecology. Print simona.musazzi MUSAZZI SIMONA andrea.lami LAMI ANDREA |
