Impacts of anthropogenic eutrophication on the carbon transfers in lacustrine food webs

A paleolimnological assessment in four mountain lakes

Bibliographic Data

ID12265273
AuthorsValentin Essert (0000-0002-3197-7397, Chrono-environnement UMR6249, CNRS Université Franche-Comté, France, corresponding author), Laurent Millet (0000-0003-2050-206X, Chrono-environnement UMR6249, CNRS Université Franche-Comté, France), Valérie Verneaux (Chrono-environnement UMR6249, CNRS Université Franche-Comté, France), Simon Belle (0000-0002-3786-5011, Swedish University of Agricultural Sciences), David Etienne (0000-0001-6388-7241, Univ. Savoie Mont Blanc, INRAE, CARRTEL, France), Hélène Masclaux (0000-0002-5869-8419, Chrono-environnement UMR6249, CNRS Université Franche-Comté, France)
Year2024
Volume34
Issue5
Pages604-618
Publication date2024-02-04
Open AccessYes
TypeARTICLE
VenueThe Holocene (JOURNAL)
Journal identifiersISSN: 0959-6836 • E-ISSN: 1477-0911
PublisherSAGE Publishing (PUBLISHER • US)
DOI10.1177/09596836231225726
OpenAlexW4391538482
LanguageEN
References cited95

Over the last decades, the intensification of anthropogenic activities and associated disturbances on lake watersheds have led to major changes in lakes trophic functioning through accelerated eutrophication. In many lakes, these changes are characterized by an unprecedented increase in organic carbon fluxes, potentially leading to a shift in biogeochemical cycles and in the balance between carbon sequestration and greenhouse gas emissions. Understanding the response of the carbon cycle to natural and anthropogenic environmental changes is becoming a crucial challenge in the context of increasing global pressures. In this study, we reconstructed the changes in the trophic functioning of the benthic and pelagic food web, in response to accelerated eutrophication in four lakes over the last millenium. Changes in carbon pathways in food webs were assessed using stable carbon isotope analysis of chitinous subfossil remains of Daphnia, Bosmina, and Chironomini archived in sedimentary records. Changes in the trophic state were inferred from sedimentary geochemical analysis, including carbon accumulation rates, Chl a accumulation rates and carbon-to-nitrogen ratios. Agro-pastoral activities were tracked by analysis of coprophilous ascospores. Results provided by this multi-proxy approach highlight recent disruptions in carbon sources and transfer pathways in lakes food webs. In particular, changes in the carbon isotopic signature of pelagic consumers suggest a recent increase in the use of 13 C-depleted carbon sources such as methanogenic or respiration-derived carbon linked to recent changes in trophic state under the intensification of anthropogenic pressures

Benthic zone · Biogeochemical cycle · Biology · Carbon cycle · Climate change · Ecosystem · Eutrophication · Food web · Holocene · Isotope analysis · Nutrient · Paleolimnology · Subfossil · Trophic level · Environmental Science · Geology and Paleoclimatology Research · Isotope Analysis in Ecology · Marine and coastal ecosystems · Ecology · Geology · Oceanography

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