Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska
When permafrost is thawing, the excess water forms so called thermokarst lakes which are very dynamic systems. In this thesis, the depositional environment of a thermokarst lake in discontinuous permafrost is characterized sedimentological and biogeochemical using four sediment cores from Goldstream...
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ftawi:oai:epic.awi.de:46513 2023-05-15T17:57:32+02:00 Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska Matuszewski, Filip 2017-11-28 application/pdf https://epic.awi.de/id/eprint/46513/ https://epic.awi.de/id/eprint/46513/1/Matuszewski_2017_BscThesis.pdf https://hdl.handle.net/10013/epic.468b056e-22ad-41b0-a07b-6e014e8267a9 https://hdl.handle.net/ unknown https://epic.awi.de/id/eprint/46513/1/Matuszewski_2017_BscThesis.pdf https://hdl.handle.net/ Matuszewski, F. (2017) Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska , Bachelor thesis, Free University Berlin. hdl:10013/epic.468b056e-22ad-41b0-a07b-6e014e8267a9 info:eu-repo/semantics/openAccess EPIC342 p. Thesis notRev info:eu-repo/semantics/other 2017 ftawi 2021-12-24T15:43:38Z When permafrost is thawing, the excess water forms so called thermokarst lakes which are very dynamic systems. In this thesis, the depositional environment of a thermokarst lake in discontinuous permafrost is characterized sedimentological and biogeochemical using four sediment cores from Goldstream Lake in Central Alaska to test the hypotheses: 1) Near-shore deposits are characterized by a coarser grain size distribution, larger minerogenic input from terrestrial origin and a mixed source of lacustrine and terrestrial organic matter whereas central lake deposits are finer grained and contain less organic matter from terrestrial origin than near-shore sediments. 2) A longer sediment record from the lake center potentially preserves pre-lake deposits which are indicated by terrestrial organic matter and low organic carbon content due to microbial decomposition in the talik. Low decomposed, terrestrial peat indicates the lake on-set and is followed by a lacustrine phase. Grain size analysis, magnetic susceptibility, total carbon, total nitrogen, total organic carbon and stable carbon isotopes were used to describe the differences between near-shore and central sediments. Furthermore, the biogeochemical methods were used to describe the sedimentary succession by distinguishing between present lake sediments with lacustrine organics and wetland peat underlaid by pre-lake sediments with terrestrial organics. The results show that central lake sediments are characterized by smaller grain sizes, less minerogenic input of terrestrial origin and a more organic matter from lacustrine origin than near-shore sediments. While present lake sediments and the wetland peat layer show the expected origin of organic matter, the pre-lake sediments indicate an older lake generation preserved below the terrestrial drainage peat. Thesis permafrost Thermokarst Alaska Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Talik ENVELOPE(146.601,146.601,59.667,59.667) |
institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
When permafrost is thawing, the excess water forms so called thermokarst lakes which are very dynamic systems. In this thesis, the depositional environment of a thermokarst lake in discontinuous permafrost is characterized sedimentological and biogeochemical using four sediment cores from Goldstream Lake in Central Alaska to test the hypotheses: 1) Near-shore deposits are characterized by a coarser grain size distribution, larger minerogenic input from terrestrial origin and a mixed source of lacustrine and terrestrial organic matter whereas central lake deposits are finer grained and contain less organic matter from terrestrial origin than near-shore sediments. 2) A longer sediment record from the lake center potentially preserves pre-lake deposits which are indicated by terrestrial organic matter and low organic carbon content due to microbial decomposition in the talik. Low decomposed, terrestrial peat indicates the lake on-set and is followed by a lacustrine phase. Grain size analysis, magnetic susceptibility, total carbon, total nitrogen, total organic carbon and stable carbon isotopes were used to describe the differences between near-shore and central sediments. Furthermore, the biogeochemical methods were used to describe the sedimentary succession by distinguishing between present lake sediments with lacustrine organics and wetland peat underlaid by pre-lake sediments with terrestrial organics. The results show that central lake sediments are characterized by smaller grain sizes, less minerogenic input of terrestrial origin and a more organic matter from lacustrine origin than near-shore sediments. While present lake sediments and the wetland peat layer show the expected origin of organic matter, the pre-lake sediments indicate an older lake generation preserved below the terrestrial drainage peat. |
format |
Thesis |
author |
Matuszewski, Filip |
spellingShingle |
Matuszewski, Filip Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
author_facet |
Matuszewski, Filip |
author_sort |
Matuszewski, Filip |
title |
Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
title_short |
Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
title_full |
Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
title_fullStr |
Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
title_full_unstemmed |
Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska |
title_sort |
sediment-biogeochemical characterization of a thermokarst lake basin in central alaska |
publishDate |
2017 |
url |
https://epic.awi.de/id/eprint/46513/ https://epic.awi.de/id/eprint/46513/1/Matuszewski_2017_BscThesis.pdf https://hdl.handle.net/10013/epic.468b056e-22ad-41b0-a07b-6e014e8267a9 https://hdl.handle.net/ |
long_lat |
ENVELOPE(146.601,146.601,59.667,59.667) |
geographic |
Talik |
geographic_facet |
Talik |
genre |
permafrost Thermokarst Alaska |
genre_facet |
permafrost Thermokarst Alaska |
op_source |
EPIC342 p. |
op_relation |
https://epic.awi.de/id/eprint/46513/1/Matuszewski_2017_BscThesis.pdf https://hdl.handle.net/ Matuszewski, F. (2017) Sediment-biogeochemical characterization of a thermokarst lake basin in Central Alaska , Bachelor thesis, Free University Berlin. hdl:10013/epic.468b056e-22ad-41b0-a07b-6e014e8267a9 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766165979900936192 |