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| Titel |
Seasonal and interannual variability of sedimentation and organic matter distribution in the Buor-Khaya Gulf: the primary recipient of input from Lena River and coastal erosion in the southeast Laptev Sea |
| VerfasserIn |
A. N. Charkin, O. V. Dudarev, I. P. Semiletov, A. V. Kruhmalev, J. E. Vonk, L. Sánchez-García, E. Karlsson, Ö. Gustafsson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 9 ; Nr. 8, no. 9 (2011-09-14), S.2581-2594 |
| Datensatznummer |
250006122
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| Publikation (Nr.) |
 copernicus.org/bg-8-2581-2011.pdf |
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| Zusammenfassung |
Climate warming is amplified in the land-sea system of
the East Siberian Arctic, which also holds large pools of vulnerable carbon
in permafrost. This coastal area is strongly influenced by sediment and
carbon transport from both its large rivers and extensive erosion of
Pleistocene permafrost along its coastline. This study is investigating the
coastal fate of the sediment and organic carbon delivered to the Buor-Khaya
Gulf, which is the first recipient of the overwhelming fluvial discharge
from the Lena River and is additionally receiving large input from extensive
erosion of the coastal ice-complex (permafrost a.k.a. Yedoma; loess soil
with high organic carbon content). Both water column suspended particulate
matter (SPM) and surface sediments were sampled at about 250 oceanographic
stations in the Gulf in this multi-year effort, including one winter
campaign, and analyzed for the distribution and sorting of sediment size,
organic carbon content, and stable carbon isotope signals. The composition
of the surface sediment suggests an overwhelmingly terrestrial contribution
from both river and coastal erosion. The objective of this paper is to
improve our understanding of the seasonal (i.e., winter vs summer) and
interannual variability of these coastal sedimentation processes and the
dynamics of organic carbon (OC) distribution in both the water column SPM
and the surface sediments of the Buor-Khaya Gulf.
Based on data collected during several years in the period
2000–2008, two different sedimentation regimes were revealed for the
Buor-Khaya Gulf, the relative importance of each at a given time depend on
hydrometeorological conditions, the Lena River water discharge and sea-ice
regime: Type 1 erosion-accumulation and Type 2 accumulation.
The Type 1 erosion-accumulation sedimentation regime is typical (2000–2006) for the ice-free
period of the year (here considered in detail for August 2005). Under such
conditions terrigenous sources of SPM and particulate organic carbon (POC)
stem predominantly from river discharge, thermal erosion of coastal
ice-complex and remobilized bottom sediments. The Type 2 accumulation sedimentation
regime develops under ice-covered conditions, and only occasionally during
the ice-free period (August 2008). In Type 2 winter, combined terrigenous
and marine-biogenic SPM and POC sources are dominating due to relatively low
overall terrigenous input (April 2007). In Type 2 summer, river alluvium
becomes the major SPM and POC source (August 2008). The water column SPM and
POC loadings vary by more than a factor of two between the two regimes. This
study underscores the necessity of multi-year investigations to better
understand the functioning of the primary recipient of terrestrially
expulsed matter in the East Siberian Arctic. |
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