SwePub
Sök i LIBRIS databas

  Utökad sökning

onr:"swepub:oai:DiVA.org:su-42115"
 

Sökning: onr:"swepub:oai:DiVA.org:su-42115" > Temporal and spatia...

Temporal and spatial dynamics in subarctic peat plateaus and thermokarst lakes

Sannel, A. Britta K., 1968- (författare)
Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK)
Kuhry, Peter, Professor (preses)
Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK)
Jansson, Peter, Professor (preses)
Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK)
visa fler...
Brown, Ian A., Dr (preses)
Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK)
Payette, Serge, Professor (opponent)
Département de Biologie, Université Laval, Québec, Canada
visa färre...
 (creator_code:org_t)
ISBN 9789174471069
Stockholm : Department of Physical Geography and Quaternary Geology (INK), Stockholm University, 2010
Engelska 36s.
Serie: Dissertations from the Department of Physical Geography and Quaternary Geology, 1653-7211 ; 23
  • Doktorsavhandling (övrigt vetenskapligt)
Abstract Ämnesord
Stäng  
  • Permafrost peatlands are widespread at high northern latitudes and are important soil organic carbon reservoirs. A future warming in these areas, as suggested by global climate models, can cause thawing and increased ground subsidence (thermokarst), resulting in changes in surface hydrology and ecosystem functioning. The aim of this thesis is to increase our knowledge of temporal and spatial dynamics in subarctic peat plateaus with interspersed thermokarst lakes in order to better understand how these ecosystems respond to climate change. Detailed plant macrofossil and carbon/nitrogen ratio analyses of two peat plateaus located in the continuous and northern discontinuous permafrost zones in west-central Canada show that permafrost conditions have been stable since permafrost developed around 5600–4500 cal yr BP. Peat plateaus act as carbon sinks over time. The lack of wet phases since the plateaus formed, despite several local fires, suggests that this type of peatlands have been negligible as methane sources throughout most of their history, representing a negative net radiative forcing on climate. Thermokarst lakes are common features in peat plateaus across the northern permafrost region. A time-series analysis of aerial photographs and high resolution satellite images in three peat plateau/thermokarst lake complexes along a climatic and permafrost gradient shows that where the mean annual air temperature (MAAT) is below -5ºC and ground temperatures are -2ºC or colder, only minor changes in thermokarst lake extent have occurred from the mid 1970s until the mid 2000s. During the same time interval extensive lake drainage and new lake formation has taken place where the MAAT is ca -3ºC and the ground temperature is close to 0ºC. In a future progressively warmer and wetter climate, permafrost degradation can cause significant impacts on landscape pattern and greenhouse gas exchange also in the vast peat plateaus presently experiencing stable permafrost conditions.

Nyckelord

Peatlands
permafrost
subarctic
peat plateau
thermokarst lake
macrofossil analysis
carbon/nitrogen ratio
peat accumulation
carbon accumulation
remote sensing
binary encoding
time-series analysis
naturgeografi
Physical Geography

Publikations- och innehållstyp

vet (ämneskategori)
dok (ämneskategori)

Hitta via bibliotek

Till lärosätets databas

Sök utanför SwePub

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy