Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments

U. Kokfelt; P. Rosen; K. Schoning; T.R. Christensen; J. Forster; J. Karlsson; N. Reuss; M. Rundgren; T.V. Callaghan; C. Jonasson; D. Hammarlund

Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments

U. Kokfelt, P. Rosen, K. Schoning, T.R. Christensen, J. Forster, J. Karlsson, N. Reuss, M. Rundgren, T.V. Callaghan, C. Jonasson, D. Hammarlund

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

73 Citationer (Scopus)

Abstract

Udgivelsesdato: 2009

Originalsprog	Engelsk
Tidsskrift	Global Change Biology
Vol/bind	15
Udgave nummer	7
Sider (fra-til)	1652-1663
Antal sider	11
ISSN	1354-1013
Status	Udgivet - 2009
Udgivet eksternt	Ja

Bibliografisk note

JEnglishArticleKokfelt, U, Lund Univ, Geobiosphere Sci Ctr, SE-22362 Lund, [email protected] PUBLISHING, INCMALDENCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAGLOB CHANGE BIOLJULDiscipline: Biodiversity Conservation; Ecology; Environmental Sciences454RK
Paper id:: doi: 10.1111/j.1365-2486.2009.01880.x

Citationsformater

@article{cfa35fe0662411de8bc9000ea68e967b,

title = "Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments",

abstract = "Recent accelerated decay of discontinuous permafrost at the Stordalen Mire in northern Sweden has been attributed to increased temperature and snow depth, and has caused expansion of wet minerotrophic areas leading to significant changes in carbon cycling in the mire. In order to track these changes through time and evaluate potential forcing mechanisms, this paper analyses a peat succession and a lake sediment sequence from within the mire, providing a record for the last 100 years, and compares these with monitored climate and active layer thickness data. The peat core was analysed for testate amoebae to reconstruct changes in peatland surface moisture conditions and water table fluctuations. The lake sediment core was analysed by near infrared spectroscopy to infer changes in the total organic carbon (TOC) concentration of the lake-water, and changes in delta C-13 and C, N and delta N-15 to track changes in the dissolved inorganic carbon (DIC) pool and the influence of diagenetic effects on sediment organic matter, respectively. Results showed that major shifts towards increased peat surface moisture and TOC concentration of the lake-water occurred around 1980, one to two decades earlier than a temperature driven increase in active layer thickness. Comparison with monitored temperature and precipitation from a nearby climate station indicates that this change in peat surface moisture is related to June-September (JJAS) precipitation and that the increase in lake-water TOC concentration reflects an increase in total annual precipitation. A significant depletion in C-13 of sediment organic matter in the early 1980s probably reflects the effect of a single or a few consecutive years with anomalously high summer precipitation, resulting in elevated DIC content of the lake water, predominantly originating from increased export and subsequent respiration of organic carbon from the mire. Based on these results, it was not possible to link proxy data obtained on peat and lake-sediment records directly to permafrost decay. Instead our data indicate that increased precipitation and anomalously high rainfall during summers had a significant impact on the mire and the adjacent lake ecosystem. We therefore propose that effects of increased precipitation should be considered when evaluating potential forcing mechanisms of recent changes in carbon cycling in the subarctic",

author = "U. Kokfelt and P. Rosen and K. Schoning and T.R. Christensen and J. Forster and J. Karlsson and N. Reuss and M. Rundgren and T.V. Callaghan and C. Jonasson and D. Hammarlund",

note = "JEnglishArticleKokfelt, U, Lund Univ, Geobiosphere Sci Ctr, SE-22362 Lund, [email protected] PUBLISHING, INCMALDENCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAGLOB CHANGE BIOLJULDiscipline: Biodiversity Conservation; Ecology; Environmental Sciences454RK Paper id:: doi: 10.1111/j.1365-2486.2009.01880.x",

year = "2009",

language = "English",

volume = "15",

pages = "1652--1663",

journal = "Global Change Biology",

issn = "1354-1013",

publisher = "Wiley-Blackwell",

number = "7",

}

TY - JOUR

T1 - Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments

AU - Kokfelt, U.

AU - Rosen, P.

AU - Schoning, K.

AU - Christensen, T.R.

AU - Forster, J.

AU - Karlsson, J.

AU - Reuss, N.

AU - Rundgren, M.

AU - Callaghan, T.V.

AU - Jonasson, C.

AU - Hammarlund, D.

N1 - JEnglishArticleKokfelt, U, Lund Univ, Geobiosphere Sci Ctr, SE-22362 Lund, [email protected] PUBLISHING, INCMALDENCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAGLOB CHANGE BIOLJULDiscipline: Biodiversity Conservation; Ecology; Environmental Sciences454RK Paper id:: doi: 10.1111/j.1365-2486.2009.01880.x

PY - 2009

Y1 - 2009

N2 - Recent accelerated decay of discontinuous permafrost at the Stordalen Mire in northern Sweden has been attributed to increased temperature and snow depth, and has caused expansion of wet minerotrophic areas leading to significant changes in carbon cycling in the mire. In order to track these changes through time and evaluate potential forcing mechanisms, this paper analyses a peat succession and a lake sediment sequence from within the mire, providing a record for the last 100 years, and compares these with monitored climate and active layer thickness data. The peat core was analysed for testate amoebae to reconstruct changes in peatland surface moisture conditions and water table fluctuations. The lake sediment core was analysed by near infrared spectroscopy to infer changes in the total organic carbon (TOC) concentration of the lake-water, and changes in delta C-13 and C, N and delta N-15 to track changes in the dissolved inorganic carbon (DIC) pool and the influence of diagenetic effects on sediment organic matter, respectively. Results showed that major shifts towards increased peat surface moisture and TOC concentration of the lake-water occurred around 1980, one to two decades earlier than a temperature driven increase in active layer thickness. Comparison with monitored temperature and precipitation from a nearby climate station indicates that this change in peat surface moisture is related to June-September (JJAS) precipitation and that the increase in lake-water TOC concentration reflects an increase in total annual precipitation. A significant depletion in C-13 of sediment organic matter in the early 1980s probably reflects the effect of a single or a few consecutive years with anomalously high summer precipitation, resulting in elevated DIC content of the lake water, predominantly originating from increased export and subsequent respiration of organic carbon from the mire. Based on these results, it was not possible to link proxy data obtained on peat and lake-sediment records directly to permafrost decay. Instead our data indicate that increased precipitation and anomalously high rainfall during summers had a significant impact on the mire and the adjacent lake ecosystem. We therefore propose that effects of increased precipitation should be considered when evaluating potential forcing mechanisms of recent changes in carbon cycling in the subarctic

AB - Recent accelerated decay of discontinuous permafrost at the Stordalen Mire in northern Sweden has been attributed to increased temperature and snow depth, and has caused expansion of wet minerotrophic areas leading to significant changes in carbon cycling in the mire. In order to track these changes through time and evaluate potential forcing mechanisms, this paper analyses a peat succession and a lake sediment sequence from within the mire, providing a record for the last 100 years, and compares these with monitored climate and active layer thickness data. The peat core was analysed for testate amoebae to reconstruct changes in peatland surface moisture conditions and water table fluctuations. The lake sediment core was analysed by near infrared spectroscopy to infer changes in the total organic carbon (TOC) concentration of the lake-water, and changes in delta C-13 and C, N and delta N-15 to track changes in the dissolved inorganic carbon (DIC) pool and the influence of diagenetic effects on sediment organic matter, respectively. Results showed that major shifts towards increased peat surface moisture and TOC concentration of the lake-water occurred around 1980, one to two decades earlier than a temperature driven increase in active layer thickness. Comparison with monitored temperature and precipitation from a nearby climate station indicates that this change in peat surface moisture is related to June-September (JJAS) precipitation and that the increase in lake-water TOC concentration reflects an increase in total annual precipitation. A significant depletion in C-13 of sediment organic matter in the early 1980s probably reflects the effect of a single or a few consecutive years with anomalously high summer precipitation, resulting in elevated DIC content of the lake water, predominantly originating from increased export and subsequent respiration of organic carbon from the mire. Based on these results, it was not possible to link proxy data obtained on peat and lake-sediment records directly to permafrost decay. Instead our data indicate that increased precipitation and anomalously high rainfall during summers had a significant impact on the mire and the adjacent lake ecosystem. We therefore propose that effects of increased precipitation should be considered when evaluating potential forcing mechanisms of recent changes in carbon cycling in the subarctic

M3 - Journal article

SN - 1354-1013

VL - 15

SP - 1652

EP - 1663

JO - Global Change Biology

JF - Global Change Biology

IS - 7

ER -