Stable carbon isotopic analyses of organic carbon (δ13C) in individual paleosol profiles
from Permian–Triassic sequences of Antarctica reveal systematic isotopic variations with …

Carbon-isotopic compositions of total carbonate, inoceramid carbonate, micritic carbonate,
secondary cements, total organic carbon, and geoporphyrins have been measured in 76 …

The organic-matter content of lake sediments provides information that is important to
studies of lacustrine paleoenvironments, the history of climate change, and the effects of …

The organic carbon cycle on Earth is divided into two parts (Fig. 4.1; Tissot and Welte 1984).
The biological cycle starts with photosynthesis of organic matter from atmospheric carbon …

Recent work has highlighted the ubiquity of bacteria and archaea and continues to affirm
their significance in diverse biogeochemical processes. The δ13C values and distributions …

Summary Uncultured ANaerobic MEthanotrophic (ANME) archaea are often assumed to be
obligate methanotrophs that are incapable of net methanogenesis, and are therefore used …

Thirty-five different samples from three different sulfur cycles were examined in this
stratigraphically oriented study of the Shell 22x-1 well (USGS C177 core) in the Piceance …

The activity of anaerobic methaneoxidizing microbes is revealed by extremely light C-
isotope values of saturated and unsaturated C20 and C25 isoprenoids(eg, crocetane, 2, 6 …

Controls on the carbon isotopic signatures of methanotroph biomarkers have been further
explored using cultured organisms. Growth under conditions which select for the membrane …

Despite many investigations concerning the insoluble organic matter in sediments
(kerogen), its chemical nature and origin are only poorly understood. Here we report the …