Geoffrey Eglinton

Even carbon number predominance of plant wax n-alkanes: a correction

Abstract The distributions of n-alkanes of four species of Micromeria have the conventional higher plant pattern of high carbon preference index (CPI) and odd-numbered carbon dominance (maxima at n-C31 or n-C33), rather than the even-numbered predominance previously reported (Palic, R., Ristic, N., Simic, N., Kitic, D., Kapetanovic, R., 1997. The alkanes from some plants of Micromeria genus. Journal of the Serbian Chemical Society 62, 619–622). The stable carbon isotope ratio values (δ13C) of the individual n-alkanes (−38 to −34‰) are typical of C3 plants. Homologous series of odd-numbered predominant iso-alkanes (i-C27 to i-C35) and even-numbered predominant anteiso-alkanes (a-C27 to a-C35) are also present (8 to 18% of the total identified alkanes) and have similar carbon isotopic ratios (−36.8 to−35.1‰).

Alkenone biomakers gain recognition as molecular paleoceanographic proxies

Questions about climate change are commanding societal as well as scientific interest. Climate records embedded in sediment cores from lakes and oceans, in coral reefs, and in polar ice cores are providing information about natural climatic variations and about linkages between the ocean, atmosphere, and cryosphere. Profound changes that occurred on submillennial timescales are superimposed on glacial-to-interglacial shifts in climate state. For example, marine sediment records reveal that abrupt oscillations in sea surface temperature (SSl), approaching the magnitude of glacial-interglacial transitions, occurred repeatedly between 65 and 11 kyr ago (i.e., between marine oxygen isotope stage 3 and the early Holocene). Indeed, the oceans are intimately linked with climate through thermohaline circulation. An entire subdiscipline, paleoceanography, is devoted to gleaning pertinent information from these sedimentary records.