In:
Biogeosciences, Copernicus GmbH, Vol. 18, No. 16 ( 2021-08-24), p. 4791-4816
Abstract:
Abstract. Lakes act as important sinks for inorganic and organic sediment components.
However, investigations of sedimentary carbon budgets within glacial lakes
are currently absent from Arctic Siberia. The aim of this paper is to
provide the first reconstruction of accumulation rates, sediment and carbon
budgets from a lacustrine sediment core from Lake Rauchuagytgyn, Chukotka
(Arctic Siberia). We combined multiple sediment biogeochemical and
sedimentological parameters from a radiocarbon-dated 6.5 m sediment core
with lake basin hydroacoustic data to derive sediment stratigraphy, sediment
volumes and infill budgets. Our results distinguished three principal
sediment and carbon accumulation regimes that could be identified across all
measured environmental proxies including early Marine Isotope Stage 2 (MIS2) (ca. 29–23.4 ka cal BP), mid-MIS2–early MIS1 (ca. 23.4–11.69 ka cal BP) and the Holocene (ca. 11.69–present). Estimated organic carbon accumulation rates (OCARs) were
higher within Holocene sediments (average 3.53 g OC m−2 a−1) than
Pleistocene sediments (average 1.08 g OC m−2 a−1) and are similar
to those calculated for boreal lakes from Quebec and Finland and Lake Baikal
but significantly lower than Siberian thermokarst lakes and Alberta glacial
lakes. Using a bootstrapping approach, we estimated the total organic carbon
pool to be 0.26 ± 0.02 Mt and a total sediment pool of 25.7 ± 1.71 Mt within a hydroacoustically derived sediment volume of ca. 32 990 557 m3. The total organic carbon pool is substantially smaller than Alaskan
yedoma, thermokarst lake sediments and Alberta glacial lakes but shares
similarities with Finnish boreal lakes. Temporal variability in sediment and
carbon accumulation dynamics at Lake Rauchuagytgyn is controlled
predominantly by palaeoclimate variation that regulates lake ice-cover
dynamics and catchment glacial, fluvial and permafrost processes through
time. These processes, in turn, affect catchment and within-lake primary
productivity as well as catchment soil development. Spatial differences compared to
other lake systems at a trans-regional scale likely relate to the
high-latitude, mountainous location of Lake Rauchuagytgyn.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-18-4791-2021
DOI:
10.5194/bg-18-4791-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2158181-2
