Molecular indicators of redox and marine photoautotroph composition in the late Middle Ordovician of Iowa, U.S.A.

Pancost, Richard D.; Freeman, Katherine H.; Patzkowsky, Mark E.; Wavrek, David A.; Collister, James W.

doi:10.1016/s0146-6380(98)00185-5

Cited by 65 publications

(37 citation statements)

References 53 publications

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“…The pristane/phytane ratio is used to assess palaeoenvironment of deposition of organic matter (Didyk et al 1978;Meyers and Snowdon 1993;Hughes et al 1995;Pancost et al 1998). Pr/Ph ratios [3 are considered to be indicative of oxic conditions, values \1 indicates anoxic conditions and Pr/Ph ratios between 1 and 3 are indicative of oxic to suboxic conditions.…”

Section: Depositional Environment and Organic Matter Typementioning

confidence: 99%

Geochemical evaluation of Niger Delta sedimentary organic rocks: a new insight

Akinlua

Torto

2010

Int J Earth Sci (Geol Rundsch)

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A geochemical evaluation of Niger Delta organic matter was carried out using supercritical fluid extraction (SFE) sample preparation procedure. Comparison of geochemical significance of gas chromatographic data of rock extracts of SFE with those of Soxhlet extraction method from previous studies was made in order to establish the usefulness of SFE in geochemical exploration. The assessment of geochemical character of the rock samples from the comparison and interpretation of other geochemical parameters were used to give more insights into understanding the source rocks characteristics of onshore and shelf portions of the Niger Delta Basin. The results of the gas chromatographic (GC) analysis of the rock extracts across the lithostratigraphic units show that Pr/Ph, Pr/nC 17 , Pr/nC 18 , CPI and odd/even preference ranged from 0.07 to 12.39, 0.04 to 6.66, 0.05 to 13.80, 0.12 to 8.4 and 0.06 to 8.12, respectively. The Rock-Eval pyrolysis data and geochemical ratios and parameters calculated from the GC data showed that most of the samples are mature and have strong terrestrial provenance while a few samples have strong marine provenance. The few marine source rocks are located in the deeper depth horizon. Pr/Ph and standard geochemical plots indicate that most of samples were derived from organic matter deposited in less reducing conditions, i.e. more of oxidizing conditions while a few samples have predominantly influence of reducing conditions. The results of trace metal analysis of older samples from Agbada Formation also indicate marine and mixed organic matter input deposited in less reducing conditions. The results obtained in this study are comparable with those obtained from previous studies when Soxhlet extraction method was used and also indicated the presence of more than one petroleum systems in the Niger Delta.

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Section: Depositional Environment and Organic Matter Typementioning

confidence: 99%

Geochemical evaluation of Niger Delta sedimentary organic rocks: a new insight

Akinlua

Torto

2010

Int J Earth Sci (Geol Rundsch)

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“…In one case, bulk microbial biomass was used to determine ␦ 13 C values (16), but there was not a concomitant determination of ␦ 13 C CO2 values, so that the carbon metabolism in situ could not be evaluated. Molecular markers of green sulfur bacteria are frequently used in geochemistry for reconstruction of past environmental conditions (19,21,24,42,43,53,55,57). However, the carbon metabolism of an extant natural community of green sulfur bacteria has never been investigated based on stable carbon isotope fractionation of specific biomarkers.…”

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confidence: 99%

“…Of the total lipids present in archaea (accounting for 2 to 6% of the cellular dry weight [26]), only a small fraction of nonpolar lipids (7 to 30%, corresponding to 0.1 to 1.8% of the cellular dry weight [26]) contains traces of farnesol (Յ2% of the nonpolar lipids [61]). 13 C values from the chemocline of Lake Dagow; ᮀ, average of ␦ 13 C values from previously published papers (for Lake Cisó and Lake Cadagno, isorenieratene from sediments [20,50]; for Ace Lake and the Black Sea, isorenieratene, chlorobactene, and farnesane from sediments [22,54,57]; for ancient sediments, isorenieratene isolated from rocks [19,21,42,55,56]). The shaded areas indicate the range of ⌬␦ 13 C values for the biomass of green and purple sulfur bacteria for the chemocline of Lake Dagow as calculated from previously published data (29,47,59) Consequently, the maximum amount of farnesol which could originate from archaeal lipids is 0.036% of the cellular dry weight.…”

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confidence: 99%

Characterization and In Situ Carbon Metabolism of Phototrophic Consortia

Glaeser

Overmann

2003

Appl Environ Microbiol

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A dense population of the phototrophic consortium "Pelochromatium roseum" was investigated in the chemocline of a temperate holomictic lake (Lake Dagow, Brandenburg, Germany). Fluorescence in situ hybridization revealed that the brown epibionts of "P. roseum" constituted up to 37% of the total bacterial cell number and up to 88% of all green sulfur bacteria present in the chemocline. Specific amplification of 16S rRNA gene fragments of green sulfur bacteria and denaturing gradient gel electrophoresis fingerprinting yielded a maximum of four different DNA bands depending on the year of study, indicating that the diversity of green sulfur bacteria was low. The 465-bp 16S rRNA gene sequence of the epibiont of "P. roseum" was obtained after sorting of individual consortia by micromanipulation, followed by a highly sensitive PCR. The sequence obtained represents a new phylotype within the radiation of green sulfur bacteria. Maximum light-dependent H 14 CO 3 ؊ fixation in the chemocline in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea suggested that there was anaerobic autotrophic growth of the green sulfur bacteria. The metabolism of the epibionts was further studied by determining stable carbon isotope ratios (␦ 13 C) of their specific biomarkers. Analysis of photosynthetic pigments by high-performance liquid chromatography revealed the presence of high concentrations of bacteriochlorophyll (BChl) e and smaller amounts of BChl a and d and chlorophyll a in the chemocline. Unexpectedly, isorenieratene and ␤-isorenieratene, carotenoids typical of other brown members of the green sulfur bacteria, were absent. Instead, four different esterifying alcohols of BChl e were isolated as biomarkers of green sulfur bacterial epibionts, and their ␦ 13 C values were determined. Farnesol, tetradecanol, hexadecanol, and hexadecenol all were significantly enriched in 13 C compared to bulk dissolved and particulate organic carbon and compared to the biomarkers of purple sulfur bacteria. The difference between the ␦ 13 C values of farnesol, the major esterifying alcohol of BChl e, and CO 2 was ؊7.1%, which provides clear evidence that the mode of growth of the green sulfur bacterial epibionts of "P. roseum" in situ is photoautotrophic.Phototrophic consortia are unique, highly structured aggregates consisting of colorless bacteria and green sulfur bacteria (34,37,41,44,52). In motile phototrophic consortia, numerous green sulfur bacteria (so-called epibionts) are attached around a single, flagellated, colorless cell of a member of the ␤ subclass of the Proteobacteria, thereby forming a barrel-shaped highly regular structure (14,15,37). Motile phototrophic consortia were first described in the early 20th century (7, 27) and since then have been detected in numerous stratified freshwater lakes and ponds worldwide (40). To date, seven different types of motile phototrophic consortia have been distinguished on the basis of color, size, and shape and on the basis of the number and morphology of the epibionts (41).Phototrophic conso...

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“…Aromatic C40 Carotenoid* Locality References Holocene 1 Black Sea Holocene 1, 2 Amvrakikos Gulf (Greece) Holocene 1, 4 Kyllaren Fjord Pliocene 1 Eastern Mediterranean Sapropels (ODP) Messinian 1 Vena del Gesso Basin (Italy) Messinian 1, 2 Gebellina Marl (Sicily) (Schaeffer et al, 1995) Oligocene 1 Menilite Formation (Poland) (Wagner et al, 2004) Late Turonian 1 Canje Formation (British Guyana) OAE-2 1, 2 North Atlantic (DSDP & ODP) OAE-1b 1 Santana Formation (Brazil) (Heimhofer et al, 2008) OAE-1a 1 Venetian Alps (Italy) (van Breugel et al, 2007) Late Jurassic 1 Kimmeridge Clay (UK) Late Jurassic 1, 2 Calcaires en Plaquettes (France) ; Van Kaam-Peters and Sinninghe Damsté, 1997) Middle Callovian 1 Oxford Clay (UK) Toarcian 1, 2 Northern Europe (Allgäu; Schistes Cartons; Posidionia) Toarcian OAE 1, 2, 4 Hawsker Bottoms; Cleveland Basin UK; MRM rock extract (French et al, 2014) Middle Sinemurian to Middle Hettangian 1 Frick Swiss Jura (Schwab and Spangenberg, 2007) Early Carboniferous 1, 3 Exshaw Formation (Canada) Upper Famennian 1, 3 Holy Cross Mountains (Poland) (Racka et al, 2010) Frasnian/Famennian 1, 3 Holy Cross Mountains (Poland) (Joachimski et al, 2001) Frasnain 1, 3 Duvernay Fm (Canada) Hartgers et al, 1993;) Early-Mid Frasnian transition 1, 3 Holy Cross Mountains (Poland) (Marynowski et al, 2008) Middle Devonian; Givetian 1, 3 Keg River Formation (Canada) (Behrens et al, 1998) Late Ordovician-Early Silurian 1, 3 Batra Formation (Jordon) (Armstrong et al, 2009) Late Ordovician 1, 3 Boas Oil Shale (Canada) Caradocian 1 Decorah Formation (USA) (Pancost et al, 1998) Middle Ordovician 1, 3 Womble Shale (USA) Late Cambrian …”

Section: Agementioning

confidence: 99%

Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina

French¹

2015

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Tracing the evolution of Earth's redox history is one of the great challenges of geobiology and geochemistry. The accumulation of photosynthetically derived oxygen transformed the redox state of Earth's surface environments, setting the stage for the subsequent evolution of complex life. However, the timing of the advent of oxygenic photosynthesis relative to the Great Oxidation Event (GOE; ~2.4 Ga) is poorly constrained. After the deep ocean became oxygenated in the early Phanerozoic, hydrogen sulfide, which is toxic to most aerobes, may have transiently accumulated in the marine photic zone (i.e. photic zone euxinia; PZE) during mass extinctions and oceanic anoxic events. Here, the molecular fossil evidence for oxygenic photosynthesis and eukaryotes is reevaluated, where the results imply that currently existing lipid biomarkers are contaminants. Next, the stratigraphic distribution of green and purple sulfur bacteria biomarkers through geologic time is evaluated to test whether these compounds reflect a water column sulfide signal, which is implicit in their utility as PZE paleoredox proxies. Results from a modern case study underscore the need to consider allochthonous and microbial mat sources and the role of basin restriction as alternative explanations for these biomarkers in the geologic record, in addition to an autochthonous planktonic source.

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Molecular indicators of redox and marine photoautotroph composition in the late Middle Ordovician of Iowa, U.S.A.

Cited by 65 publications

References 53 publications

Geochemical evaluation of Niger Delta sedimentary organic rocks: a new insight

Geochemical evaluation of Niger Delta sedimentary organic rocks: a new insight

Characterization and In Situ Carbon Metabolism of Phototrophic Consortia

Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina

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