Inland waters play a crucial role in the global carbon cycle, with organic carbon (OC) burial in lake sediments constituting carbon removal from rapidly cycling Earth surface pools. However, the nature of sequestered OC has different climatic implications. The burial of recently synthesized terrestrial and aquatic biospheric OC represents a rapid drawdown of atmospheric carbon. In contrast, the burial of aged soil OC sequesters carbon on longer timescales, and the re-burial of rock-derived carbon has no net effect on atmospheric CO2. Therefore, it is crucial to distinguish the origin of OC when quantifying lake sediment carbon budgets. We aim to contribute to the understanding of carbon burial in inland waters by investigating the sources and dynamics of organic carbon accumulation in Swiss lake sediments. We use the natural climatic, lithological, and ecological gradients of several lake catchments within different biogeographical regions in Switzerland to assess controls on the abundance, sources, and dynamics of OC accumulating within their sediments over the last century. We focus on the use of radiocarbon 14C as a tool to determine the age and origin of OC. In particular, the 20th -century 14C “bomb spike” offers the possibility of constraining carbon dynamics and deconvoluting inputs on decadal time scales through down-core investigation of lacustrine records. Our investigation also highlights the challenges in understanding the nature of allochthonous carbon in these systems.
Primary Presenter: Benedict Mittelbach, ETH Zurich (benedict.mittelbach@erdw.ethz.ch)
Authors:
Benedict Mittelbach, Geological Institute, Dept. Earth Science, ETH Zürich, Switzerland (benedict.mittelbach@erdw.ethz.ch)
Alexander Brunmayr, Imperial College London, Space & Atmospheric Physics, Physics, London, United Kingdom (alexander.brunmayr19@imperial.ac.uk)
Margot White, Geological Institute, Dept. Earth Science, ETH Zürich, Switzerland (margot.white@erdw.ethz.ch)
Timo Rhyner, Geological Institute, Dept. Earth Science, ETH Zürich, Switzerland (timo.rhyner@erdw.ethz.ch)
Negar Haghipour, Laboratory for Ion Beam Physics, ETH Zürich, Switzerland (negar.haghipour@erdw.ethz.ch)
Nathalie Dubois, Dept. Surface Waters Research & Management, EAWAG, Dübendorf ,Switzerland (Nathalie.Dubois@eawag.ch)
Timothy Eglinton, Geological Institute, Dept. Earth Science, ETH Zürich, Switzerland (timothy.eglinton@erdw.ethz.ch)
Tracing Organic Carbon Sources and Turnover Times Using Sedimentaty Radiocarbon Signatures in Swiss Lakes
Category
Scientific Sessions > SS031 Old Carbon, New Ideas – Recent Advances in Understanding Lentic Carbon Burial
Description
Time: 03:45 PM
Date: 9/6/2023
Room: Sala Menorca B