Change search
ReferencesLink to record
Permanent link

Direct link
Calibrating n-alkane Sphagnum proxies in sub-Arctic Scandinavia
Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
2009 (English)In: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 40, no 10, 1085-1090 p.Article in journal (Refereed) Published
Abstract [en]

Moss covered, high latitude wetlands hold large amounts of terrestrial organic matter (OM), which may be vulnerable to expected climate warming. Molecular analysis of fluvially transported material from these regions can distinguish between different sources of terrestrial OM. Sphagnum moss may represent one of the major sources. This study aimed to quantitatively establish a molecular proxy for identifying Sphagnum-derived OM from high latitude peatlands in the sub-Arctic coastal ocean. We collected and analyzed Sphagnum species throughout northern Sweden and Finland. Results show that the C25/(C25 + C29) n-alkane ratio is most suitable for terrestrial OM source apportionment in these coastal regions since, compared to other n-alkane Sphagnum proxies, it shows (i) the least variation between species, (ii) the most constant values for different latitudinal regimes and (iii) the largest dynamic range to the higher plant end member in two-source mixing models. Application of the proxy to surface sediments and suspended particulate matter in the sub-Arctic northern Baltic Sea shows that 68–103% of the terrestrial OM fraction is derived from Sphagnum-rich peatland. We recommend that future studies on terrestrial OM fluxes into (sub-)Arctic regions should apply the C25/(C25 + C29) proxy to improve insight into the contribution of Sphagnum-derived terrestrial OM from climate-vulnerable, high latitude wetlands.

Place, publisher, year, edition, pages
2009. Vol. 40, no 10, 1085-1090 p.
National Category
Earth and Related Environmental Sciences Natural Sciences
URN: urn:nbn:se:su:diva-36967DOI: 10.1016/j.orggeochem.2009.07.002ISI: 000275197600005OAI: diva2:291451
Available from: 2010-02-01 Created: 2010-02-01 Last updated: 2011-04-19Bibliographically approved
In thesis
1. Molecular and isotopic characterization of terrestrial organic carbon released to (sub-)Arctic coastal waters
Open this publication in new window or tab >>Molecular and isotopic characterization of terrestrial organic carbon released to (sub-)Arctic coastal waters
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Arctic soils store half of the global soil organic carbon (OC) pool and twice as much C as is currently present in the atmosphere. A considerable part of these carbon pools are stored in permafrost. Amplified climate warming in the Arctic will thaw permafrost and remobilize some of these substantial carbon stocks into the active carbon cycle, potentially causing positive feedback to global warming. Despite the global importance of this mechanism, our understanding of the fate of these thawing organic carbon (OC) pools is still poor, particularly regarding its degradation potential. This makes good estimates on greenhouse gas emissions versus coastal reburial impossible. This doctoral thesis aims to improve our understanding on the fate of high-latitude terrestrial OC during fluvial and coastal transport. In two study regions, the Bothnian Bay and the East Siberian Sea, we apply a wide range of bulk, molecular and isotopic geochemical analyses to reveal information on sources, age, degradation and transport routes.

Our results show that both study regions receive and store large amounts of terrestrial OC, largely derived from peatlands (paper I, II and IV). This terrestrial matter undergoes extensive degradation in both the water column and surface sediments (paper I, III and IV). Surface sediments in the East Siberian Sea show a offshore-decreasing input of riverine OC and a considerable and constant input of OC from coastal erosion. The strong imprint of rapidly settling coastal OC far out on the shelf may be explained by a strong benthic boundary layer transport in combination with offshore ice-transport and selective preservation of erosion OC compared to riverine OC (paper IV). Molecular radiocarbon data allowed us to distinguish between two (sub-)Arctic soil OC pools that show a remarkably different susceptibility to degradation upon arrival in the coastal system; a young and easily degradable pool originating in surface peatlands, and an old and recalcitrant pool originating in deep mineral soils and coastal mineral Pleistocene deposits (paper III and IV). Our first estimates suggest that, in the Bothnian Bay coastal system, mineral soil OC is at least 20 times less susceptible to degradation than peatland OC (paper III). Hence, a considerable part of the thaw-released mineral OC pool may simply be relocated to coastal sediments instead of being emitted to the atmosphere.

Place, publisher, year, edition, pages
Stockholm: Department of Applied Environmental Science (ITM), Stockholm University, 2010. 51 p.
organic carbon, terrestrial biomarkers, radiocarbon, particulate organic carbon, sediments, sphagnum, Arctic, Bothnian Bay, East Siberian Sea, Kalix River, Kolyma River
Research subject
Applied Environmental Science
urn:nbn:se:su:diva-38589 (URN)978-91-7447-057-4 (ISBN)
Public defence
2010-05-21, Nordenskiöldsalen, Geovetenskapens Hus, Svante Arrheniusväg 12, Stockholm, 10:00 (English)
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Accepted. Paper 4: Manuscript. Available from: 2010-04-28 Created: 2010-04-19 Last updated: 2010-04-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Gustafsson, Örjan
By organisation
Department of Applied Environmental Science (ITM)
In the same journal
Organic Geochemistry
Earth and Related Environmental SciencesNatural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 80 hits
ReferencesLink to record
Permanent link

Direct link