Radiocarbon Stocktaking of Swiss Lakes: Relevance to Carbon Budgets and Dynamics


EMBARGOED UNTIL 2035-01-01

Date

2022

Publication Type

Conference Poster

ETH Bibliography

yes

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EMBARGOED UNTIL 2035-01-01

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Abstract

Inland waters play a crucial role in the global carbon cycle, with organic carbon (OC) burial in lake sediments constituting a removal of carbon 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 drawdown of atmospheric carbon. In contrast, the reburial of petrogenic OC exerts no net effect on atmospheric CO2 levels, while oxidation of petrogenic carbon releases CO2. Therefore, it is crucial to distinguish the origin of OC when quantifying lake sediment carbon budgets. Radiocarbon (14C) is a powerful tool to distinguish between recent, pre-aged, and fossil carbon sources. Moreover, the 20th-Century radiocarbon “bomb spike” offers the possibility of constraining carbon dynamics and deconvolute inputs on decadal time scales through down-core investigation of lacustrine records including quantitatively disentangling different sources of OC, which exhibit contrasting susceptibilities to remineralization. Switzerland hosts various lake catchments within different biogeographical ecoregions, experiencing contrasting degrees of climate change. We use these natural gradients to assess controls on the abundance, sources, and dynamics of OC accumulating within Swiss lake sediments over the last century. We combine 14C and stable δ13C isotope signatures of bulk OC from sediment cores from a range of lake systems to constrain the nature and dynamics of OC accumulation. These data form the foundation for more in-depth investigations using 14C measurements on source-specific biomarkers to constrain the temporal dynamics and transport pathways of biospheric carbon and to refine carbon stocktaking assessments.

Publication status

published

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Journal / series

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Pages / Article No.

Publisher

ETH Zurich

Event

36th Congress of the International Society of Limnology (SIL 2022)

Edition / version

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Subject

Radiocarbon C-14; Carbon cycle; Lake sediments; Biogeochemical cycles; 14C

Organisational unit

03868 - Eglinton, Timothy I. (emeritus) / Eglinton, Timothy I. (emeritus) check_circle

Notes

Funding

193770 - Radiocarbon Inventories of Switzerland (RICH): An integrated approach to understand the changing carbon cycle (SNF)

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