TY - JOUR
T1 - Sterols in red and green algae
T2 - Quantification, phylogeny, and relevance for the interpretation of geologic steranes
AU - Kodner, R. B.
AU - Pearson, A.
AU - Summons, R. E.
AU - Knoll, A. H.
PY - 2008/9
Y1 - 2008/9
N2 - Steroids, a class of triterpenoid lipids with high preservation potential, are widely distributed in sedimentary rocks. All eukaryotes have a physiological requirement for these molecules, making steroids important biomarkers for aiding our understanding of eukaryote molecular evolution and geologic history. C26-C30 sterols are the molecules most commonly incorporated or synthesized by eukaryotes, and correspond to C 26-C30 steranes ubiquitously and abundantly preserved in petroleums and sedimentary bitumens. Because these sterols occur in evolutionarily diverse taxa, it can be difficult to associate any particular compound with a single group of organisms. Nevertheless, geochemists have still been able to draw parallels between the empirical patterns in geologic sterane abundances and the age of petroleum source rocks. Paleobiologists have also used sterane data, in particular the patterns in C29 and C28 steranes, to support fossil evidence of an early radiation of green algae in latest Proterozoic and Paleozoic and the succession of the major modern phytoplankton groups in the Mesozoic. Although C29 sterols are found in many eukaryotes, organisms that produce them in proportional abundances comparable to those preserved in Proterozoic and Paleozoic rocks are limited. Based on a large, phylogenetically based survey of sterol profiles from the kingdom Plantae, we conclude that modern ulvophyte and early diverging prasinophyte green algae produce high abundances of C29 relative to C27 and C28 sterols most consistent with the sterane profiles observed in Paleozoic rocks. Our analysis also suggests that ancestral stem groups among the Plantae, including the glaucocystophytes and early divergent red algae are also plausible candidates.
AB - Steroids, a class of triterpenoid lipids with high preservation potential, are widely distributed in sedimentary rocks. All eukaryotes have a physiological requirement for these molecules, making steroids important biomarkers for aiding our understanding of eukaryote molecular evolution and geologic history. C26-C30 sterols are the molecules most commonly incorporated or synthesized by eukaryotes, and correspond to C 26-C30 steranes ubiquitously and abundantly preserved in petroleums and sedimentary bitumens. Because these sterols occur in evolutionarily diverse taxa, it can be difficult to associate any particular compound with a single group of organisms. Nevertheless, geochemists have still been able to draw parallels between the empirical patterns in geologic sterane abundances and the age of petroleum source rocks. Paleobiologists have also used sterane data, in particular the patterns in C29 and C28 steranes, to support fossil evidence of an early radiation of green algae in latest Proterozoic and Paleozoic and the succession of the major modern phytoplankton groups in the Mesozoic. Although C29 sterols are found in many eukaryotes, organisms that produce them in proportional abundances comparable to those preserved in Proterozoic and Paleozoic rocks are limited. Based on a large, phylogenetically based survey of sterol profiles from the kingdom Plantae, we conclude that modern ulvophyte and early diverging prasinophyte green algae produce high abundances of C29 relative to C27 and C28 sterols most consistent with the sterane profiles observed in Paleozoic rocks. Our analysis also suggests that ancestral stem groups among the Plantae, including the glaucocystophytes and early divergent red algae are also plausible candidates.
UR - http://www.scopus.com/inward/record.url?scp=49249126099&partnerID=8YFLogxK
U2 - 10.1111/j.1472-4669.2008.00167.x
DO - 10.1111/j.1472-4669.2008.00167.x
M3 - Article
C2 - 18624688
AN - SCOPUS:49249126099
SN - 1472-4677
VL - 6
SP - 411
EP - 420
JO - Geobiology
JF - Geobiology
IS - 4
ER -