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Contrasts in dissolved, particulate and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
(2022)EGUsphereArctic rivers will be increasingly affected by the hydrological and biogeochemical consequences of thawing permafrost. During transport, permafrost-derived organic carbon (OC) can either accumulate in floodplain and shelf sediments or be degraded into greenhouse gases prior to final burial. Thus, the net impact of permafrost OC on climate will ultimately depend on the interplay of complex processes that occur along the source-to-sink ...Working Paper -
The influence of lateral transport on sedimentary alkenone paleoproxy signals
(2021)Biogeosciences DiscussionsAlkenone signatures preserved in marine sedimentary records are considered one of the most robust paleothermometers available, and are often used as a proxy for paleoproductivity. However, important gaps remain on the provenance and fate of alkenones, and their impact on derived environmental signals in marine sediments. Here, we analyze the abundance, distribution, and radiocarbon (14C) age of alkenones in bulk sediments and corresponding ...Working Paper -
Co-evolution of terrestrial and aquatic ecosystem structure with hydrological change in the Holocene Baltic Sea
(2021)Climate of the Past DiscussionsThe Baltic Sea experienced a number of marine transgressions and regressions throughout the Holocene. These fluctuations in sea level coupled with substantial regional ice melt led to isostatic adjustment and periodic isolation from the North Sea. Here, we determine the distributions and isotopic signatures of organic compounds preserved in a sediment record spanning the last ~ 11 ka in order to reconstruct environmental change under these ...Working Paper -
MOSAIC (Modern Ocean Sediment Archive and Inventory of Carbon): A (radio)carbon-centric database for seafloor surficial sediments
(2020)Earth System Science Data DiscussionsMapping the biogeochemical characteristics of surficial ocean sediments is crucial for advancing our understanding of global element cycling, as well as for assessment of the potential footprint of environmental change. Despite their importance as long-term repositories for biogenic materials produced in the ocean and delivered from the continents, biogeochemical signatures in ocean sediments remain poorly delineated. Here, we introduce ...Working Paper -
Microbial lipid signatures in Arctic deltaic sediments - insights into methane cycling and climate variability
(2020)EarthArXivGlycerol Dialkyl Glycerol Tetraethers (GDGTs) are ubiquitous biomolecules whose structural diversity or isotopic composition is increasingly used to reconstruct environmental changes such as air temperatures or pCO2. Isoprenoid GDGTs, in particular GDGT-0, are biosynthesized by a large range of Archaea. To assess the potential of GDGT-0 as a tracer of past methane cycle variations, three sediment cores from the Mackenzie River Delta have ...Working Paper -
Climatic variations during the Holocene inferred from radiocarbon and stable carbon isotopes in a high-alpine cave
(2020)Climate of the Past DiscussionsA novel technique making use of laser ablation coupled online to accelerator mass spectrometry (LA-AMS) allows analyzing the radiocarbon (14C) concentration in carbonate samples continuously at high spatial resolution within very short analysis times. This new technique can provide radiocarbon data similar to the spatial resolution of stable carbon (C) isotope measurements by isotope-ratio mass spectrometry (IRMS) and, thus, can help to ...Working Paper -
Millennial-age GDGTs in forested mineral soils: 14C-based evidence for stabilization of microbial necromass
(2020)Biogeosciences DiscussionsUnderstanding controls on the persistence of soil organic matter (SOM) is essential to constrain its role in the carbon cycle and inform climate-carbon cycle model predictions. Emerging concepts regarding formation and turnover of SOM imply that it is mainly comprised of mineral-stabilized microbial products and residues, however, direct evidence in support of this concept remains limited. Here, we introduce and test a method for isolation ...Working Paper