Archaeal intact polar lipids in polar waters: a comparison between the Amundsen and Scotia seas

• Published in: Biogeosciences
• Main Authors: C. L. Spencer-Jones, E. L. McClymont, N. J. Bale, E. C. Hopmans, S. Schouten, J. Müller, E. P. Abrahamsen, C. Allen, T. Bickert, C.-D. Hillenbrand, E. Mawbey, V. Peck, A. Svalova, J. A. Smith
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Ecology; QH540-549.5; Life; QH501-531; Geology; QE1-996.5; Amundsen Sea; Antarctic; Scotia Sea; Southern Ocean; West Antarctic Ice Sheet; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.5194/bg-18-3485-2021; https://doaj.org/article/fc6b02e6c11b4cd8941095b59f5965a9

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 complexities 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. TEX 86 and TEX <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">86</mn><mi>L</mi></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="11pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="f5aa8d040bb936b7027dab100dc81056"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-18-3485-2021-ie00001.svg" width="11pt" height="17pt" src="bg-18-3485-2021-ie00001.png"/></svg:svg> ), 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 populations in suspended particulate matter (SPM) from the Amundsen Sea and the Scotia Sea. SPM samples from the Amundsen Sea were collected from up to four water column depths representing the surface waters through to Circumpolar Deep Water (CDW), whereas the Scotia Sea samples were collected along a transect encompassing the sub-Antarctic front through to the ...