Journal
SCIENCE OF THE TOTAL ENVIRONMENT
Volume 672, Issue -, Pages 657-668Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.scitotenv.2019.03.459
Keywords
Lipids biomarkers; Lakes; Organic matter; Maritime Antarctica; Isotopes
Categories
Funding
- Instituto Antartico Uruguayo (IAU)
- Spanish Ministry of Science, Innovation and Universities (MICINN/FEDER) [RYC-2014-19446, CGL2015-74254JIN]
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Lakes are important paleoenvironmental archives retaining abundant information due to their typical high sedimentation rates and susceptibility to environmental changes. Here, we scrutinize the organic matter (OM) composition, origin and preservation state in surface sediments from five lakes in a remote, warming-sensitive, and poorly explored region partially covered by the retreating Collins Glacier in King George Island (Antarctica), the Fildes Peninsula. Lipid biomarkers of terrestrial origin (i.e. high-molecular weight n-alkanes, n-alkanoic acids, and n-alkanols; beta-sitosteroL campesterol, and stigmasterol) were detected in the five Fildes Lakes, with the smallest basin (i.e., Meltwater) showing a particularly strong moss imprint. Aquatic source indicators such as low C/N and terrestrial over aquatic ratios (TAR), or less negative delta C-13 values were preferentially found in the mid-sized lakes (i.e., Drake and Ionospheric). Sedimentary carbon in the larger lakes (i.e., Uruguay and Kitezh) displayed a largely biogenic origin (i.e., values of carbon preference index, CPI, >> 1), whereas the three lakes close to Collins Glacier (i.e., Drake, Meltwater, and Ionospheric) showed certain contribution from petrogenic sources (CPI similar to 1). The results suggest that the geochemical signature of the surface sediments in the five Fildes lakes is determined by factors such as the distance to the retreating Collins Glacier, the proximity to the coast, or the lake depth. This study illustrates the forensic interest of combining lipid biomarkers, compound-specific isotopic analysis, and bulk geochemistry to reconstruct paleoenvironments and study climate-sensitive regions. (C)2019 The Authors. Published by Elsevier B.V.
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