Publication Date:
2019-02-21
Description:
Global warming has a direct impact on the degradation of permafrost and the resulting ground
subsidence. Thermokarst lakes develop. During the formation of thermokarst lakes, the
thawing of permafrost releases methane and carbon, which was locked in the frozen ground
before. As a result, the generation of thermokarst lakes is directly linked to climatic changes.
The aim of this research is to reconstruct the initiation of lakes which are situated in the
discontinuous permafrost of Goldstream Valley, Central Alaska. In course of an expedition in
summer 2017, cores from eleven thermokarst lakes were taken from Goldstream Valley in
Central Alaska. The samples were analysed for sedimentological and biochemical parameters.
Additionally, macro remains were examined.
There are three classes of thermokarst lakes within this research: Lakes which develop over
a longer period of time and lakes which developed in less time. The third class includes lakes
where the initiation phase was not caught within the selected transition zones, but it is assumed
they also developed over a longer period of time and therefore belong to class one. A distinct
peat layer is characteristic for lakes of class one. The analysed macro remains reflect the
degree of degradation of the sediment except in one case. In case of biochemical analyses,
the macro remains are only partly reflected.
An implication of thermokarst lake development is a release of a high amount of methane and
carbon dioxide while thermokarst lakes develop. So, the more time a lake needs to originate,
the higher the emissions of methane and carbon dioxide are. Lakes that form within less time
therefore emit less methane and carbon dioxide.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Thesis
,
notRev
,
info:eu-repo/semantics/other
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