TEX86

TEX₈₆ is a paleothermometer based on the composition of membrane lipids of the marine picoplankton Crenarchaeota.

Wuchter et al. (2004) found that the number of cyclopentane rings in Crenarchaeota membrane lipids changes linearly with temperature in order to regulate membrane fluidity. The sedimentary composition of such lipids - which exist as far back as the early Cretaceous - can therefore be used to reconstruct average temperatures experienced by the plankton, and thus of the past water column.

This method was used by Jenkyns et al. (2004) to show that average sea surface temperatures in the currently ice covered Arctic Ocean (80 degrees N) were as high as 15 degrees Celsius in the late Cretaceous.

References

• Schouten, S., Hopmans, E.C., Schefus, E., and Sinninghe Damste, 2002, Distributional variation in marine crenarchaeotal membrane lipids: a new tool for reconstructing ancient sea water temperatures?: Earth and Planetary Science Letters, v. 204, p. 265-274.

• Wuchter, C., Schouten, S., Coolen, M., Damste, J. (2004) Temperature-dependent variation in the distribution of tetraether membrane lipids of marine Crenarchaeota: Implications for TEX86 paleothermometry. PALEOCEANOGRAPHY 19: PA4028

• Jenkyns, H., Forster, A., Schouten, S., Damste, J (2004) High temperatures in the Late Cretaceous Arctic Ocean. Nature 432: 888-891.