Evaluating branched tetraether lipid-based palaeotemperature proxies in an urban, hyper-eutrophic polluted lake in South Africa
2012 (English)In: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 53, 45-51 p.Article in journal (Refereed) Published
We evaluate the application of the branched glycerol dialkyl glycerol tetraether (br GDGT) based palaeotemperature and palaeoenvironmental proxy to a hyper-eutrophic, polluted and shallow oxic lake. Lake Zeekoevlei is the largest freshwater lake in South Africa, located close to Cape Town. We use published lake-based and soil-based calibration equations, and compare the reconstructed mean annual air temperature (MAT) with regional (South African) and local (Cape Town) instrumental temperature records. The distribution of br GDGTs in the lake sediments is influenced by air temperature. The lake-based calibration equation, which uses the methylation index of branched tetraethers/cyclisation ratio of branched tetraethers (MBT/CBT), formulated for African lakes (Tierney et al., 2010), fits well with the instrumental temperature records. Moreover, the CBT-derived pH likely reflects historic socioeconomic changes in catchment. Our results suggest that a polluted/hyper-eutrophic status and shallow water urban setting do not preclude application of the MBT/CBT-MAT proxy. However, further research is necessary to understand the behaviour of br GDGT–producing bacteria in polluted and highly productive lakes.
Place, publisher, year, edition, pages
Elsevier , 2012. Vol. 53, 45-51 p.
IdentifiersURN: urn:nbn:se:liu:diva-87467DOI: 10.1016/j.orggeochem.2012.06.005ISI: 000312605100009OAI: oai:DiVA.org:liu-87467DiVA: diva2:589474
Funding Agencies|Swedish Research Council, University of Glasgow||SUERC||
The title of this article while in manuscript was "Reconstructing short term local air temperature using branched tetraether lipids in Lake Zeekoevlei sediments in South Afrika".2013-04-182013-01-182013-04-18Bibliographically approved