The northeastern Black Sea redox zone: Hydrochemical structure and its temporal variability

Yakushev, E. V.; Часовников, В. К.; Debol’skaya, E. I.; Егоров, А. А.; Makkaveev, P. N.; Pakhomova, Svetlana; Подымов, О. И.; Yakubenko, V.G.

doi:10.1016/j.dsr2.2006.05.019

Cited by 29 publications

(13 citation statements)

References 26 publications

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“…1B). The mean of σ θ = 16.15 kg m −3 corresponds to the value determined in recent years (Yakushev et al. , 2006) as well as a decade ago (Murray et al.…”

Section: Resultssupporting

confidence: 59%

“…1B). The mean of sq = 16.15 kg m -3 corresponds to the value determined in recent years (Yakushev et al, 2006) as well as a decade ago (Murray et al, 1995). Employing the potential density of 16.15 kg m -3 as an indicator for the top of the sulfidic zone, the variations in the vertical position of the sulfidic zone were analysed across the Black Sea basin.…”

Section: Resultssupporting

confidence: 52%

Section: Resultsmentioning

confidence: 94%

“…Similarly, extended time series of sulfide measurements in the eastern Black Sea demonstrated only minor (i.e. < 10 m) seasonal and interannual changes in the position of the sulfidic zone over the past 8 years (Yakushev et al, 2006). Based on the vertical gradients in underwater irradiances determined in the present study, an upward movement of the sulfidic layers by less than 10 m would still not enable photosynthetic growth outside the centre of the Black Sea (compare 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2 ND 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2 170 400 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2 170 400 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2 A.…”

Section: Horizontal Variations In Physiological Activity Of Chlorobiumentioning

confidence: 83%

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Large‐scale distribution and activity patterns of an extremely low‐light‐adapted population of green sulfur bacteria in the Black Sea

Marschall

Jogler

Henssge

et al. 2010

Environmental Microbiology

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The Black Sea chemocline represents the largest extant habitat of anoxygenic phototrophic bacteria and harbours a monospecific population of Chlorobium phylotype BS-1. High-sensitivity measurements of underwater irradiance and sulfide revealed that the optical properties of the overlying water column were similar across the Black Sea basin, whereas the vertical profiles of sulfide varied strongly between sampling sites and caused a dome-shaped three-dimensional distribution of the green sulfur bacteria. In the centres of the western and eastern basins the population of BS-1 reached upward to depths of 80 and 95 m, respectively, but were detected only at 145 m depth close to the shelf. Using highly concentrated chemocline samples from the centres of the western and eastern basins, the cells were found to be capable of anoxygenic photosynthesis under in situ light conditions and exhibited a photosynthesis-irradiance curve similar to low-light-adapted laboratory cultures of Chlorobium BS-1. Application of a highly specific RT-qPCR method which targets the internal transcribed spacer (ITS) region of the rrn operon of BS-1 demonstrated that only cells at the central station are physiologically active in contrast to those at the Black Sea periphery. Based on the detection of ITS-DNA sequences in the flocculent surface layer of deep-sea sediments across the Black Sea, the population of BS-1 has occupied the major part of the basin for the last decade. The continued presence of intact but non-growing BS-1 cells at the periphery of the Black Sea indicates that the cells can survive long-distant transport and exhibit unusually low maintenance energy requirements. According to laboratory measurements, Chlorobium BS-1 has a maintenance energy requirement of approximately 1.6-4.9.10(-15) kJ cell(-1) day(-1) which is the lowest value determined for any bacterial culture so far. Chlorobium BS-1 thus is particularly well adapted to survival under the extreme low-light conditions of the Black Sea, and can be used as a laboratory model to elucidate general cellular mechanisms of long-term starvation survival. Because of its adaptation to extreme low-light marine environments, Chlorobium BS-1 also represents a suitable indicator for palaeoceanography studies of deep photic zone anoxia in ancient oceans.

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“…1B). The mean of σ θ = 16.15 kg m −3 corresponds to the value determined in recent years (Yakushev et al. , 2006) as well as a decade ago (Murray et al.…”

Section: Resultssupporting

confidence: 59%

Section: Resultssupporting

confidence: 52%

Section: Resultsmentioning

confidence: 94%

Section: Horizontal Variations In Physiological Activity Of Chlorobiumentioning

confidence: 83%

See 2 more Smart Citations

Large‐scale distribution and activity patterns of an extremely low‐light‐adapted population of green sulfur bacteria in the Black Sea

Marschall

Jogler

Henssge

et al. 2010

Environmental Microbiology

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“…The Black Sea is a permanently stratified basin. Chemical profiles occur in a predictable sequence on density surfaces through the Black Sea (Murray et al ., ), although decadal (Konovalov & Murray, ), interannual (Fuchsman et al ., ), and seasonal variability (Yakushev et al ., ) in the concentrations of chemical species have been observed in some instances. The Black Sea has been stratified for over 7000 years (Jones & Gagnon, ), which is in contrast with transiently oxygenated basins such as the Baltic Sea (Hannig et al ., ) or fjords such as Saanich Inlet (Manning et al ., ), where periodic oxygenation events affect microbial activity.…”

Section: Discussionmentioning

confidence: 98%

Metabolic strategies of free-living and aggregate-associated bacterial communities inferred from biologic and chemical profiles in the Black Sea suboxic zone

Fuchsman

Kirkpatrick

Brazelton

et al. 2011

FEMS Microbiol Ecol

101

162

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The Black Sea is a permanently anoxic basin with a well-defined redox gradient. We combine environmental 16S rRNA gene data from clone libraries, terminal restriction fragment length polymorphisms, and V6 hypervariable region pyrosequences to provide the most detailed bacterial survey to date. Furthermore, this data set is informed by comprehensive geochemical data; using this combination of information, we put forward testable hypotheses regarding possible metabolisms of uncultured bacteria from the Black Sea's suboxic zone (microaerophily, nitrate reduction, manganese cycling, and oxidation of methane, ammonium, and sulfide). Dominant bacteria in the upper suboxic zone included members of the SAR11, SAR324, and Microthrix groups and in the deep suboxic zone included members of BS-GSO-2, Marine Group A, and SUP05. A particulate fraction (30 μm filter) was used to distinguish between free-living and aggregate-attached communities in the suboxic zone. The particulate fraction contained greater diversity of V6 tag sequences than the bulk water samples. Lentisphaera, Epsilonproteobacteria, WS3, Planctomycetes, and Deltaproteobacteria were enriched in the particulate fraction, whereas SAR11 relatives dominated the free-living fraction. On the basis of the bacterial assemblages and simple modeling, we find that in suboxic waters, the interior of sinking aggregates potentially support manganese reduction, sulfate reduction, and sulfur oxidation.

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A model of phototrophic sulfide oxidation in a stratified estuary

Findlay

Toro

Luther

2017

Limnology & Oceanography

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Sulfide accumulated as a result of microbial sulfate reduction in sediments and the bottom waters of stratified systems can be re-oxidized via an array of biotic and abiotic reactions. A one-dimensional diffusion-reaction model was developed and applied to 4 yr of physical and chemical data from the stratified water column of the Chesapeake Bay in order to quantify the impact of different sulfide oxidation processes at the redox interface during slack tide. This dataset and the model simulations highlight short-term and interannual variation in the physical structure and the distribution of key redox species (O 2 , H 2 S, S 0 , Fe 21 , Mn 21 , FeOOH, MnO 2 ) throughout the water column. The model evaluates links between oxygen, sulfur, iron and manganese cycling, and includes the novel consideration of sulfide oxidation by phototrophic sulfide oxidizing bacteria (PSOB), which are a common component of the Bay. Model simulations demonstrate that phototrophic sulfide oxidation can account for up to 58% of total sulfide oxidation, depending upon the depth of the oxic/anoxic interface. The results of this study yield an approach to parameterizing PSOB activity, and quantify the variable role that PSOB play in sulfide oxidation in the Chesapeake Bay as redox conditions in the water column change, which has applications for both modern and ancient environments.

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The northeastern Black Sea redox zone: Hydrochemical structure and its temporal variability

Cited by 29 publications

References 26 publications

Large‐scale distribution and activity patterns of an extremely low‐light‐adapted population of green sulfur bacteria in the Black Sea

Large‐scale distribution and activity patterns of an extremely low‐light‐adapted population of green sulfur bacteria in the Black Sea

Metabolic strategies of free-living and aggregate-associated bacterial communities inferred from biologic and chemical profiles in the Black Sea suboxic zone

A model of phototrophic sulfide oxidation in a stratified estuary

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