Cryogenic soil processes in a changing climate
A considerable part of the global pool of terrestrial carbon is stored in high latitude soils. In these soils, repeated cycles of freezing and thawing creates soil motion (cryoturbation) that in combination with other cryogenic disturbance processes may play a profound role in controlling the carbon...
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Umeå universitet, Institutionen för ekologi, miljö och geovetenskap
2016
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ftumeauniv:oai:DiVA.org:umu-112509 2023-10-09T21:48:47+02:00 Cryogenic soil processes in a changing climate Kryogena mark processer i ett föränderligt klimat Becher, Marina 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112509 eng eng Umeå universitet, Institutionen för ekologi, miljö och geovetenskap Umeå : Umeå universitet http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112509 urn:isbn:978-91-7601-361-8 info:eu-repo/semantics/openAccess Non-sorted circle Carbon storage Soil motion Terrestrial photogrammetry Cryoturbation Carbon fluxes Other Earth and Related Environmental Sciences Annan geovetenskap och miljövetenskap Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2016 ftumeauniv 2023-09-22T13:48:51Z A considerable part of the global pool of terrestrial carbon is stored in high latitude soils. In these soils, repeated cycles of freezing and thawing creates soil motion (cryoturbation) that in combination with other cryogenic disturbance processes may play a profound role in controlling the carbon balance of the arctic soil. Conditions for cryogenic soil processes are predicted to dramatically change in response to the ongoing climate warming, but little is known how these changes may affect the ability of arctic soils to accumulate carbon. In this thesis, I utilize a patterned ground system, referred to as non-sorted circles, as experimental units and quantify how cryogenic soil processes affect plant communities and carbon fluxes in arctic soils. I show that the cryoturbation has been an important mechanism for transporting carbon downwards in the studied soil over the last millennia. Interestingly, burial of organic material by cryoturbation appears to have mainly occurred during bioclimatic events occurring around A.D. 900-1250 and A.D. 1650-1950 as indicated by inferred 14C ages. Using a novel photogrammetric approach, I estimate that about 0.2-0.8 % of the carbon pool is annually subjected to a net downward transport induced by the physical motion of soil. Even though this flux seems small, it suggests that cryoturbation is an important transporter of carbon over centennial and millennial timescales and contributes to translocate organic matter to deeper soil layers where respiration proceeds at slow rates. Cryogenic processes not only affect the trajectories of the soil carbon, but also generate plant community changes in both species composition and abundance, as indicated by a conducted plant survey on non-sorted circles subjected to variable differential frost heave during the winter. Here, disturbance-tolerant plant species, such as Carex capillaris and Tofieldia pusilla, seem to be favoured by disturbance generated by the differential heave. Comparison with findings from a previous plant survey on ... Doctoral or Postdoctoral Thesis Arctic Umeå University: Publications (DiVA) Arctic |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
Non-sorted circle Carbon storage Soil motion Terrestrial photogrammetry Cryoturbation Carbon fluxes Other Earth and Related Environmental Sciences Annan geovetenskap och miljövetenskap |
spellingShingle |
Non-sorted circle Carbon storage Soil motion Terrestrial photogrammetry Cryoturbation Carbon fluxes Other Earth and Related Environmental Sciences Annan geovetenskap och miljövetenskap Becher, Marina Cryogenic soil processes in a changing climate |
topic_facet |
Non-sorted circle Carbon storage Soil motion Terrestrial photogrammetry Cryoturbation Carbon fluxes Other Earth and Related Environmental Sciences Annan geovetenskap och miljövetenskap |
description |
A considerable part of the global pool of terrestrial carbon is stored in high latitude soils. In these soils, repeated cycles of freezing and thawing creates soil motion (cryoturbation) that in combination with other cryogenic disturbance processes may play a profound role in controlling the carbon balance of the arctic soil. Conditions for cryogenic soil processes are predicted to dramatically change in response to the ongoing climate warming, but little is known how these changes may affect the ability of arctic soils to accumulate carbon. In this thesis, I utilize a patterned ground system, referred to as non-sorted circles, as experimental units and quantify how cryogenic soil processes affect plant communities and carbon fluxes in arctic soils. I show that the cryoturbation has been an important mechanism for transporting carbon downwards in the studied soil over the last millennia. Interestingly, burial of organic material by cryoturbation appears to have mainly occurred during bioclimatic events occurring around A.D. 900-1250 and A.D. 1650-1950 as indicated by inferred 14C ages. Using a novel photogrammetric approach, I estimate that about 0.2-0.8 % of the carbon pool is annually subjected to a net downward transport induced by the physical motion of soil. Even though this flux seems small, it suggests that cryoturbation is an important transporter of carbon over centennial and millennial timescales and contributes to translocate organic matter to deeper soil layers where respiration proceeds at slow rates. Cryogenic processes not only affect the trajectories of the soil carbon, but also generate plant community changes in both species composition and abundance, as indicated by a conducted plant survey on non-sorted circles subjected to variable differential frost heave during the winter. Here, disturbance-tolerant plant species, such as Carex capillaris and Tofieldia pusilla, seem to be favoured by disturbance generated by the differential heave. Comparison with findings from a previous plant survey on ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Becher, Marina |
author_facet |
Becher, Marina |
author_sort |
Becher, Marina |
title |
Cryogenic soil processes in a changing climate |
title_short |
Cryogenic soil processes in a changing climate |
title_full |
Cryogenic soil processes in a changing climate |
title_fullStr |
Cryogenic soil processes in a changing climate |
title_full_unstemmed |
Cryogenic soil processes in a changing climate |
title_sort |
cryogenic soil processes in a changing climate |
publisher |
Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112509 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112509 urn:isbn:978-91-7601-361-8 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779311851951095808 |