Isoprenoid and branched GDGT-based proxies for surface sediments from marine, fjord and lake environments in Chile

Abstract

Sinninhe Damsté, J.S. (2015). Isoprenoid and branched GDGTbased proxies for surface sediments from marine, fjord and lake environments in Chile, Organic Geochemistry,[89][90] The NIOZ Repository gives free access to the digital collection of the work of the Royal Netherlands Institute for Sea Research. This archive is managed according to the principles of the Open Access Movement, and the Open Archive Initiative. Each publication should be cited to its original source -please use the reference as presented. When using parts of, or whole publications in your own work, permission from the author(s) or copyright holder(s) is always needed. suggesting in situ production of certain br GDGTs in the water column or surface sediment.For the lakes, MBT'/CBT-based surface air temperature estimates were 3 to 6 °C below MAAT. However, temperature estimates from the lake-specific MBT/CBT global calibration were in good agreement with mean annual surface temperature for all the lakes. The results highlight the need for testing local vs. global calibrations of GDGT-based proxies before their application for palaeoenvironmental reconstruction. Key words:GDGT; TEX 86 ; BIT; MBT'; CBT; calibration; marine; fjord; lake; Chile 3 IntroductionGlycerol dialkyl glyceryl tetraethers (GDGTs) are membrane lipids of archaea and bacteria and occur ubiquitously in aquatic environments and soils (reviewed by Schouten et al., 2013).Thaumarchaeota (formerly Group 1 Crenarchaeota; Brochier-Armanet et al., 2008;Spang et al., 2010), a specific phylogenetic cluster of the Archaea domain occurring widely in marine and lake systems (e.g. Karner et al., 2001; Keough et al., 2003), biosynthesize isoprenoid (iso)GDGTs (structures in Appendix 1) containing 0-4 cyclopentane moieties and crenarchaeol, which has a cyclohexane moiety in addition to four cyclopentane moieties Sinninghe Damsté et al., 2002;Pitcher et al., 2011a). Another group of GDGTs containing branched (br) instead of isoprenoid alkyl chains (Appendix 1) was initially discovered in peat bogs (Sinninghé Damsté et al., 2000) and subsequently shown to be ubiquitous in soils, coastal marine and lake sediments (e.g. Schouten et al., 2000;Weijers et al., 2006a Weijers et al., , 2007aSinninghe Damsté et al., 2008;Huguet et al., 2010; Loomis et al., 2011). Acidobacteria thriving in soil are a likely source of brGDGTs (Weijers et al., 2006a(Weijers et al., , 2009 Sinninghé Damsté et al., 2011, 2014. Although brGDGTs occur mainly in soil and peat, they are probably also produced in situ in the water column and/or the sediments of marine and freshwater (lake and river) environments (e.g. Peterse et al., 2009;Sinninghe Damsté et al., 2009; Tierney and Russell, 2009; Tierney et al., 2010a; Pearson et al., 2011; Zhu et al., 2011; Loomis et al., 2011 Loomis et al., , 2012 Loomis et al., , 2014 Zell et al., 2013; Buckles et al., 2014; De Jonge et al., 2014a; Weijers et al., 2014). Although GDGT-based proxies are being used increasingly for palaeoclimate reconstruction (e.g. Tierney et al., 2...

Lake Water Depth Controlling Archaeal Tetraether Distributions in Midlatitude Asia: Implications for Paleo Lake‐Level Reconstruction

“…The %cren and depth values of the newly added samples almost fall within the range for our midlatitude Asian lakes, while the %cren‐depth relation is slightly improved for the integrated data set (from 0.71 to 0.76, Figure b). Moreover, we also note reported significant and positive correlations between %cren (or crenarchaeol concentration) and water depth for lakes in South America (Kaiser et al, ) and East Africa (Tierney et al, ; Figure S4). Therefore, the positive %cren‐depth relationship is valid for lakes in Asia and probably other regions as well, and %cren can be widely used to track past lake‐level variation, at least qualitatively.…”

A Late Quaternary climate record based on long chain diol proxies from the Chilean margin

“…There is also a regional TEX H 86 calibration available, based on Chilean surface sediments between 25 and 50 °S (Kaiser et al, 2015): 20 SST = 59.6 × TEX 86 + 33.0…”

“…Although the outcomes are relatively similar, the calibration of Kim et al (2010) resulted in SSTs that agreed better with the U K´3 7 and LDI records, and therefore we have used this calibration. In Appendix A, the TEX H 86 temperatures based on the calibration of 25 Kaiser et al (2015) are plotted ( Fig. A1).…”

“…Overall, the TEX H 86 record agrees reasonably well with the U K´3 7 record for ODP 1234, suggesting that it mainly reflects SST. Also, Kaiser et al (2015) who established a regional TEX H 86 calibration suggested that this proxy mainly reflects SST. However, all cross-correlations still reveal relatively large scatter, reflecting the multiple different constraints on the respective 5 proxies, as each one is affected by different parameters and can reflect different seasonal temperatures.…”

“…TEX86 records for ODP 1234 applying different calibrations, i.e., the global core-top calibration of Kim et al (2010) in red (TEX H 86), the local core-top calibration of Kaiser et al (2015) in purple and the Bayesian model of Tierney and Tingley (2014;2015) in green applying the BAYSPAR tool (http://bayspar.geo.arizona.edu/). For the BAYSPAR 5 calculation we have assumed a prior mean 13 °C and a search tolerance of 0.2 TEX86 units.…”