Uncoupled organic matter burial and quality in boreal lake sediments over the Holocene
2015 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 120, no 9, 1751-1763 p.Article in journal (Refereed) Published
Boreal lake sediments are important sites of organic carbon (OC) storage, which have accumulated substantial amounts of OC over the Holocene epoch; the temporal evolution and the strength of this Holocene carbon (C) sink is, however, not well constrained. In this study we investigated the temporal record of carbon mass accumulation rates (CMARs), and assessed qualitative changes of terrestrially derived OC in the sediment profiles of seven Swedish boreal lakes, in order to evaluate the variability of boreal lake sediments as a C sink over time.
CMARs were resolved on a short-term (centennial) and long-term (i.e. over millennia of the Holocene) time scale, using radioactive lead (210 Pb) and carbon (14C) isotope dating. Sources and degradation state of terrestrially derived OC were identified and characterized by molecular analyses of lignin phenols.
We found that CMARs varied substantially on both short-term and long-term scales, and that the variability was mostly attributed to sedimentation rates and uncoupled from the OC content in the sediment profiles. The lignin phenol analyses revealed that woody material from gymnosperms was a dominant and constant OC source to the sediments over the Holocene. Furthermore, lignin-based degradation indices, such as acid-to-aldehyde ratios, indicated that post-depositional degradation in the sediments was very limited on longer time scales, implying that terrestrial OC is stabilized in the sediments on a permanent basis.
Place, publisher, year, edition, pages
2015. Vol. 120, no 9, 1751-1763 p.
organic carbon, accumulation rates, radiocarbon dating, lead dating, lignin phenols, carbon sink
Research subject Biology with specialization in Limnology
IdentifiersURN: urn:nbn:se:uu:diva-260660DOI: 10.1002/2015JG002987ISI: 000363332900004OAI: oai:DiVA.org:uu-260660DiVA: diva2:851741
FunderSwedish Research Council Formas