https://wiki.linked.earth/wiki/index.php?action=history&feed=atom&title=TEX86 2026-05-09T13:55:14Z Revision history for this page on the wiki MediaWiki 1.26.3 https://wiki.linked.earth/wiki/index.php?title=TEX86&diff=87709&oldid=prev 2020-11-12T15:26:28Z

<p>WTBootstrap: New Instance TEX86</p> <p><b>New page</b></p><div>=== TEX86 ===<br /> <br /> The use of TEX86 (TetraEther indeX of 86 carbons) as a tool to reconstruct past sea surface temperature variability is based on the relative cyclization of isoprenoidal glycerol dialkyl glycerol tetra ethers (GDGTs) produced by marine archaea. TEX86 is defined as [1]:<br /> <br /> TEX_{86}=\frac{GDGT-2+GDGT-3+Cren'}{GDGT-1+GDGT-2+GDGT-3+Cren'}<br /> <br /> where GDGTs 1-3 indicate compounds containing 1-3 cyclopentyl moieties, respectively, and Cren' denotes the regioisomer of crenarchaeol, a diagnostic biomarker for the Thaumarchaeota, the primary producers of GDGTs in the marine realm. By definition, values of the TEX86 index are comprised between 0 and 1.<br /> <br /> Experimental evidence suggests that archaea produce GDGTs with more rings warmer waters, a response observed in cultures of hyperthermophile archaea [2] [3] and mesocosm experiments with natural seawater containing heterogenous archaeal population [4] [5].<br /> References<br /> <br /> [1] Schouten, S., Hopmans, E. C., Schefuß, E., &amp; Sinninghe Damsté, J. S. (2002). Distributional variations in marine crenarchaeotal membrane lipids: a new organic proxy for reconstructing ancient sea water temperatures? . Earth and Planetary Science Letters, 204, 265-274.<br /> <br /> [2] de Rosa, M., Esposito, E., Gambacorta, A., Nicolaus, B., &amp; Bu'Lock, J. (1980). Effects of temperature on ether lipid composition of Caldariella acidophilia. Phytochemistry, 19, 827-831.<br /> <br /> [3] Uda, I., Sugai, A., Itoh, Y., &amp; Itoh, T. (2001). Variation in molecular species of polar liipds from Thermoplasma acidophilum depends on growth temperature. Lipids, 36, 103-105.<br /> <br /> [4] Wuchter, C., Schouten, S., Coolen, M. J. L., &amp; Sinninghe Damsté, J. S. (2004). Temperature-dependent variation in the distribution of tetraether membrane lipids of marine Crenarchaeota: implications for TEX86 paleothermometry. Paleoceanography, 19, PA4028. doi:10.1029/2004PA001041<br /> <br /> [5]Schouten, S., Forster, A., Panato, E., &amp; Sinninghe Damsté, J. S. (2007). Towards the calibration of the TEX86 paleothermometer on ancient greenhouse worlds. Organic Geochemistry. doi:10.1016/j.orggeochem.2007.05.014<br /> <br /> &lt;!-- Do not edit below this unless you know what you are doing --&gt;<br /> [[Category:OrganicIndex]]</div>

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