Hydrocarbon Distribution of Algae and Bacteria, and Microbiological Activity in Sediments

Abstract

Abstract.-The chemical taxonomic relationship of microorganisms has been studied through the hydrocarbon fraction of their chemical constituents. The diagenesis and biological transformations of some hydrocarbons in sediments is suggested, as a result of this information.Various compounds of presumed biological origin have been isolated from petroleum,' ancient sediments,2-4 and meteorites.5 Among these classes of organic compounds, the hydrocarbons have probably received the most attention. Meinscheinr found that the extracts of soil contained more odd than even carbon-numbered normal paraffins. Bray' reported that the ratio of odd over even carbon-numbered n-paraffins is significant in Recent sediments, approximately 2.4 to 5.5. However, the value decreases for older sediments, and it is close to 1.0 in petroleum. The isoprenoid hydrocarbons with the regular headtail-head-tail linkage have been taken to be the residue of life forms.3Barghoorn and his co-workers8' 9 claimed to have found blue-green algae and bacterialike microfossils in Precambrian rocks. It is very important to obtain confirmatory evidence for the existence of these primitive microorganisms in the Precambrian period.Chemical criteria can be used as confirmatory evidence for classifying living organisms which were previously identified solely on the basis of morphologic characteristics. Chemistry may have more to contribute than any morphological analysis, not only because of the relative evanescence of most plant tissues in geological deposits, but also because the biochemistry of evolutionary processes may be deduced from the presence of compounds from known diagenic pathways.The evolutionary step from the procaryotic cell (blue-green algae and bacteria) to the eucaryotic cell (green algae, fungi, protozoa, higher plants, and animals) is recognized by the appearance (or presence, in some cases) of nuclear membrane, mitotic division, chromosome number, cytoplasmic streaming, and mitochondria in the eucaryotic cell. Since lipids are important constituents of cytoplasmic and intracellular membranes, chemical taxonomic studies have been made to determine whether such evolutionary transitions are reflected at the molecular level.

Scientific Opinion on Mineral Oil Hydrocarbons in Food

“…As shown for the cyanobacteria Nostoc muscorum, the n-alkanes are formed by decarboxylation of fatty acids, e.g. stearic acid yielding n-C 17 (Han and Calvin, 1969). However, in algae n-alkanes are also formed through biosynthesis from acetate and pyruvate, since when these precursors were incubated as radiolabelled material with the blue-green algae Anabena variabilis, incorporation of radioactivity into heptadecane was observed (Fehler and Light, 1972, cited by Lester, 1979).…”

Sedimentary lipid biogeochemistry of an hypereutrophic alkaline lagoon

“…Besides these two n-alkanes, a number of hydrocarbons are also indicative of autochthonous inputs. Thus, the linear and branched C,,-Czo monounsaturated olefins are common in algae and cyanobacteria (HAN and CALVIN, 1969;GELPI et al, 1968) the methylheptadecanes are specific cyanobacterial indicators of the distributions of n-alkenes found in lacustrine environ-(HAN et GELPI et al, 1970). ments.…”

“…Peak identifications and concentration ranges are given in Tables 3 and 4. n-Heptadecane is the dominant hydrocarbon in both sediment and water particulates, a compound that usually represents algal contributions (CLARK and BLUMER, 1967;HAN et al, 1968). Another important component in the sediments is n-octadecane, the most abundant hydrocarbon in many yeast and bacterial species (HAN and CALVIN, 1969;BIRD and LYNCH, 1974;HAN et al, 1968). Besides these two n-alkanes, a number of hydrocarbons are also indicative of autochthonous inputs.…”

Water, plants, and early human habitats in eastern Africa

“…The response of algal « lipid/water values to salinity is markedly consistent at 0.9‰ ± 0.2‰ ppt −1 (7). Heptacosane (nC 17 ) is a general biomarker for algae (36) and is abundant in lake sediments from Olduvai Gorge. Modern studies establish an apparent fractionation between freshwater and nC 17 equal to −172‰ (7), and we use this value to determine algal « lipid/water values at different salinities-termed « lake values:…”