Heterogeneous responses of lake CO2 to nutrients and warming in perialpine lakes imprinted in subfossil cladoceran δ13C values

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_7009ACAB3E12
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Heterogeneous responses of lake CO2 to nutrients and warming in perialpine lakes imprinted in subfossil cladoceran δ13C values
Journal
Science of The Total Environment
Author(s)
Rantala Marttiina V., Bruel Rosalie, Marchetto Aldo, Lami Andrea, Spangenberg Jorge E., Perga Marie-Elodie
ISSN
0048-9697
Publication state
Published
Issued date
08/2021
Peer-reviewed
Oui
Volume
782
Pages
146923
Language
english
Abstract
Global change transforms processes regulating carbon dioxide (CO2) concentrations in lakes, yet our understanding of the broad-scale responses of lake CO2 to global and local human perturbation across heterogeneous landscapes and multidecadal time scales is limited. We examined decadal variability in the carbon isotope (δ13C) composition of subfossil zooplankton (Branchiopoda: Cladocera) in seven large clear perialpine lakes, including three previously studied sites, to decipher different patterns in summer surface CO2 concentrations. Generalized additive models were used to examine whether and how these patterns connect to changing nutrient regimes and anthropogenic warming over the past century. In all but one of the lakes shifts in cladoceran δ13C values coincided with turning points in the eutrophication history, broadly implying decreasing summer surface CO2 concentrations driven by phosphorus fertilization of pelagic primary production. Yet where nutrient concentrations remained below mesotrophic levels, the positive relationship between δ13C and phosphorus diminished indicating that the strong biotic control of CO2 concentrations was overwritten, probably by catchment inorganic carbon inputs and internal biochemical processes. Even under extensive nutrient loading, the connection was further weakened in lakes with high catchment to lake area ratio attributable to increased catchment interference and shorter water residence times. Warming of the perialpine region was also imprinted in the isotope records, yet the temperature effects appeared modest and were restricted to three smaller lakes with lower drainage ratios. In these lakes, warming contributed to declining cladoceran δ13C values likely partially driven by epilimnetic deepening increasing CO2 in surface waters. Overall, our results manifest the broad heterogeneity of lake responses to global change and point to the importance of hydrogeomorphic context in shaping the sensitivity and responses of lake CO2 to changing nutrient regimes and warming at the regional scale.
Keywords
Carbon cycling, Climate warming, Eutrophication, Stable carbon isotopes, Subfossil, Cladocera, Paleolimnology
Web of science
Open Access
Yes
Funding(s)
University of Lausanne
SERI (SEFRI)
Swiss National Science Foundation
Create date
07/04/2021 13:37
Last modification date
03/12/2022 6:48
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