Review status: this preprint is currently under review for the journal BG.
Archaeal Intact Polar Lipids in Polar Waters: A Comparison Between
the Amundsen and Scotia Seas
Charlotte L. Spencer-Jones1,Erin L. McClymont1,Nicole J. Bale2,Ellen C. Hopmans2,Stefan Schouten2,3,Juliane Müller4,E. Povl Abrahamsen5,Claire Allen5,Torsten Bickert4,Claus-Dieter Hillenbrand5,Elaine Mawbey5,Victoria Peck5,Aleksandra Svalova6,and James A. Smith5Charlotte L. Spencer-Jones et al.Charlotte L. Spencer-Jones1,Erin L. McClymont1,Nicole J. Bale2,Ellen C. Hopmans2,Stefan Schouten2,3,Juliane Müller4,E. Povl Abrahamsen5,Claire Allen5,Torsten Bickert4,Claus-Dieter Hillenbrand5,Elaine Mawbey5,Victoria Peck5,Aleksandra Svalova6,and James A. Smith5
1Department of Geography, Durham University, Lower Mountjoy, South Road, Durham, DH1 3LE, UK
2NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands
3Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
4Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, 27568 Bremerhaven, Germany
5British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
6School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
1Department of Geography, Durham University, Lower Mountjoy, South Road, Durham, DH1 3LE, UK
2NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands
3Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
4Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, 27568 Bremerhaven, Germany
5British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
6School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
Received: 07 Sep 2020 – Accepted for review: 28 Oct 2020 – Discussion started: 05 Nov 2020
Abstract. The West Antarctic Ice Sheet (WAIS) is one of the largest potential sources of future sea-level rise, with glaciers draining the WAIS thinning at an accelerating rate over the past 40 years. Due to difficulties in calibrating palaeoceanographic proxies for the Southern Ocean, it remains difficult to assess whether similar changes have occurred earlier during the Holocene or whether there is underlying centennial to millennial scale forcing in oceanic variability. Archaeal lipid – based proxies, specifically Glycerol Dialkyl Glycerol Tetraether (GDGT) (e.g. TEX86 and TEX86L) are powerful tools for reconstructing ocean temperature, but these proxies have been shown previously to be difficult to apply to the Southern Ocean. A greater understanding of the parameters that control Southern Ocean GDGT distributions would improve the application of these biomarker proxies and thus help provide a longer-term perspective on ocean forcing of Antarctic ice sheet changes. In this study, we characterised intact polar lipid (IPL) - GDGTs, representing (recently) living archaeal population in suspended particulate matter from the Amundsen Sea and the Scotia Sea. Shifts in IPL-GDGT signatures across well-defined fronts of the Southern Ocean revealed a correlation between the physicochemical parameters of these water masses and IPL-GDGT distributions. Further analysis is required to elucidate the additional role of productivity and nutrient availability on Southern Ocean IPL-GDGT distributions. Of particular note for proxy development in the Amundsen Sea is that IPL-GDGTs are likely actively synthesised at Circumpolar Deep Water depths and may be a significant source of GDGTs exported to the sedimentary record in this region.