A high resolution historical record of Holocene anoxygenic primary production in the Black Sea

Repeta, Daniel J.

doi:10.1016/0016-7037(93)90334-s

Cited by 97 publications

(40 citation statements)

References 23 publications

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“…Within the subsequent 3,000 years, the O 2 -H 2 S interface rose from the bottom at 2,200 m depth toward the surface (13). The presence of green sulfur bacterial photosynthetic pigments and their degradation products in subfossil sediments suggests that photic zone anoxia occurred already more than 6,000 years ago (41,47).…”

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confidence: 98%

Physiology and Phylogeny of Green Sulfur Bacteria Forming a Monospecific Phototrophic Assemblage at a Depth of 100 Meters in the Black Sea

Manske

Glaeser

Kuypers

et al. 2005

Appl Environ Microbiol

233

210

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The biomass, phylogenetic composition, and photoautotrophic metabolism of green sulfur bacteria in the Black Sea was assessed in situ and in laboratory enrichments. In the center of the western basin, bacteriochlorophyll e ( The Black Sea represents the largest extant anoxic water body worldwide. Its stratified water column comprises a ϳ60-m-thick oxic top layer, a ϳ40-m-thick suboxic intermediate zone devoid of sulfide and oxygen, and a ϳ2,000-m-deep sulfidic bottom zone (32). Bottom water anoxia was initiated 7,000 to 8,000 years ago by the intrusion of saltwater from the Mediterranean via the Bosporus strait (44). Within the subsequent 3,000 years, the O 2 -H 2 S interface rose from the bottom at 2,200 m depth toward the surface (13). The presence of green sulfur bacterial photosynthetic pigments and their degradation products in subfossil sediments suggests that photic zone anoxia occurred already more than 6,000 years ago (41, 47).Different bacteriochlorophyll e (Bchl e) homologs, as well as the carotenoids isorenieratene and ␤-isorenieratene, were detected in chemocline samples (43). These photosynthetic pigments are specific for brown-colored species of the green sulfur bacteria. Red autofluorescent cells became visible after fixation of chemocline samples (4). Since this autofluorescence is due to the formation of free bacteriopheophytins from bacteriochlorophylls (52), it was used to quantify green sulfur bacterial cell numbers, yielding a fraction of 10% of the total bacterial cell numbers (corresponding to Յ8 ϫ 10 4 cells ml Ϫ1 ) (4). Theoretically, the green sulfur bacteria could be metabolically active in the chemocline and thus be relevant for the biogeochemical cycles in the Black Sea (43).A brown-colored green sulfur bacterium, Chlorobium phaeobacteroides MN1, was previously enriched from chemocline water samples (34). First growth experiments indicated that this bacterium is adapted to low-light conditions and could divide at a light intensity of 0.25 mol quanta m Ϫ2 s Ϫ1 , but was inhibited at Ն200 mol quanta m Ϫ2 s Ϫ1 . No data are available on the physiology of this bacterium at lower light intensities. To date, the in situ light conditions in the Black Sea chemocline have not been determined. It is also unknown whether the enriched bacterium is representative for the natural assemblage of green sulfur bacteria present in the chemocline.In order to quantify anoxygenic photosynthesis in the chemocline and to elucidate its role in the carbon and sulfur cycles of the Black Sea, the in situ light intensities and the photosynthetic metabolism of the dominant phototrophic organisms need to be elucidated under natural conditions. The Black Sea also serves as a model system for past oceanic anoxic events

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confidence: 98%

Physiology and Phylogeny of Green Sulfur Bacteria Forming a Monospecific Phototrophic Assemblage at a Depth of 100 Meters in the Black Sea

Manske

Glaeser

Kuypers

et al. 2005

Appl Environ Microbiol

233

210

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“…The fossil record of isorenieratene in Black Sea sediments has been used to assess these conditions in the past and, thus, provides a reconstruction of variations in the depth of the chemocline (ref. 26).…”

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confidence: 99%

The fate of carotenoids in sediments: An overview

Damsté¹,

Koopmans²

1997

Pure and Applied Chemistry

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Despite carotenoids being abundant natural products, there are only scattered literature reports of carotenoid derivatives (mainly in the form of their 'perhydro' derivatives) in ancient sediments and petroleum. This was thought to be due to the sensitivity of carotenoids toward oxygen and their preservation potential in sediments was judged to be low. Detailed studies in the past years have indicated, however, that the fossil 'perhydro' derivatives of carotenoids represent only the tip of the iceberg and that a number of reactions occurring with the polyene chain (i.e. expulsion of toluene and xylene, cyclisation and aromatisation, reaction with reduced inorganic sulfur species, hydrogenation, C-C bond cleavage) determine the fate of carotenoids in ancient sediments and lead to complex mixtures of carotenoid derivatives. In addition, aromatisation of cyclohexenyl moieties (as present in e.g. pcarotene) occurs. An overview of these reactions is given.

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“…Based on geochemical evidence, an initial freshwater period lasted from 22,000 years before the present until about 9,000 years before the present (7) and was followed by inundation of the Black Sea basin by salt water after glacial melting and a rise in the level of the Mediterranean Sea (18). This converted the Black Sea into an anoxic marine basin and resulted in deposition of organic carbon-rich sapropel layers (Unit II) on top of the older limnic sediments (Unit III) (33,43). The presence of pigment biomarkers of obligately anoxygenic phototrophic green sulfur bacteria in Unit II sediments indicates that water column anoxia reached the photic zone about 7,200 to 6,200 years ago (33,38).…”

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confidence: 99%

“…This converted the Black Sea into an anoxic marine basin and resulted in deposition of organic carbon-rich sapropel layers (Unit II) on top of the older limnic sediments (Unit III) (33,43). The presence of pigment biomarkers of obligately anoxygenic phototrophic green sulfur bacteria in Unit II sediments indicates that water column anoxia reached the photic zone about 7,200 to 6,200 years ago (33,38). Initially, sediments with higher organic carbon contents (Unit IIb) were deposited, and this was followed by a period of lower productivity and increased input of terrigenous material (Unit IIa) (17,18).…”

mentioning

confidence: 99%

“…Isorenieratene/␤-isorenieratene and chlorobactene occur almost exclusively in the obligately anaerobic phototrophic green sulfur bacteria (38,43) and therefore have served as indicators for stable stratification of the water column and sulfidic conditions during deposition of Units I and IIb (33,38,43). However, since the ϳ80 known phylotypes of green sulfur bacteria contain only these two types of characteristic carotenoids, these compounds alone do not permit differentiation between species occupying different niches, such as freshwater and marine environments or low-and highlight-intensity environments (5).…”

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confidence: 99%

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Subfossil 16S rRNA Gene Sequences of Green Sulfur Bacteria in the Black Sea and Their Implications for Past Photic Zone Anoxia

Manske

Henssge

Glaeser

et al. 2008

Appl Environ Microbiol

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At present, the Black Sea represents the largest anoxic water body on Earth, and 87 to 92% of the Black Sea volume is permanently anoxic (3,21,39). In the center of the Black Sea, sulfide-containing water layers extend upward to 82 to 110 m below the sea surface (24,35,39). In the chemocline, green sulfur bacteria form a 20-m-thick layer persisting at in situ light intensities of 0.0022 to 0.0008 mol quanta m Ϫ2

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A high resolution historical record of Holocene anoxygenic primary production in the Black Sea

Cited by 97 publications

References 23 publications

Physiology and Phylogeny of Green Sulfur Bacteria Forming a Monospecific Phototrophic Assemblage at a Depth of 100 Meters in the Black Sea

Physiology and Phylogeny of Green Sulfur Bacteria Forming a Monospecific Phototrophic Assemblage at a Depth of 100 Meters in the Black Sea

The fate of carotenoids in sediments: An overview

Subfossil 16S rRNA Gene Sequences of Green Sulfur Bacteria in the Black Sea and Their Implications for Past Photic Zone Anoxia

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