Surface and mid-water sources of organic carbon by photoautotrophic and chemoautotrophic production in the Black Sea

Yılmaz, Ali Özgür; Çoban-Yıldız, Yeşim; Telli-Karakoç, Fatma; Bologa, Alexandru S.

doi:10.1016/j.dsr2.2006.03.015

Cited by 45 publications

(32 citation statements)

References 33 publications

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“…3B). Since our measurements were conducted around solar noon, close to the summer solstice and after the spring diatom bloom (Yilmaz et al. , 2006), it has to be concluded that green sulfur bacteria will never attain light saturation of photosynthetic growth anywhere in the Black Sea chemocline.…”

Section: Resultsmentioning

confidence: 99%

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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Section: Resultsmentioning

confidence: 99%

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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“…Furthermore, they noticed that below the suboxic boundary, large filamentous cells (>10 µm) contribute about 53% of the total bacterial biomass. During the same cruise in the Black Sea central gyre and in Sakarya canyon regions, Yilmaz et al (2006) noticed the occurrence of chemoautotrophic organisms, which contributed between 30 to 89% of the overall water column production. This chemoautotrophic activity and the importance of the methanotrophic microbial mats in the anoxic Black Sea is now rather well documented (see Michaelis et al 2002;Durisch-Kaiser et al 2005;Treude et al 2007).…”

Section: Resultsmentioning

confidence: 99%

“…In these conditions, the amount of chemoautotrophic material required to yield sedimentary organic carbon with a realistic apparent age of 1300 yr (reservoir age) is rather low: between 12% with chemoautotrophic matter at 15 pMC and photosynthetic matter at 95 pMC and 17% with chemoautotrophic matter at 15 pMC and photosynthetic matter 100 pMC. Such amounts of chemoautotrophic material are realistic if we refer firstly to the estimates of Yilmaz et al (2006) or Morgan et al (2006) and secondly to the fact that photosynthetic organic matter is partly oxidized in the oxic part of the water column, enhancing the contribution of chemoautotrophic matter, which directly sink in the anoxic water column without any direct oxidation process.…”

Section: Resultsmentioning

confidence: 99%

Variations in ¹⁴C Reservoir Ages of Black Sea Waters and Sedimentary Organic Carbon During Anoxic Periods: Influence of Photosynthetic Versus Chemoautotrophic Production

et al. 2009

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ABSTRACT. Radiocarbon activity of dissolved inorganic carbon has been measured in the northwestern Black Sea. Both continental shelf and open-sea profiles show that surface waters are in equilibrium with the atmosphere. The observed distribution of 14 C activity shows a weak contribution of the deep 14 C-depleted CO 2 to the photic zone. Such a distribution of 14 C within the water column is unable to explain the aging of sedimentary organic matter and reservoir ages greater than 500 yr. A contribution of production by chemoautotrophic bacteria feeding on 14 C-depleted methane at the boundary of the oxic and anoxic zones is a realistic hypothesis. Also, a contribution to sedimentary organic carbon estimated at <15% of the photosynthetic primary production could explain 14 C reservoir ages greater than 1300 yr.

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“…Significant dark carbon fixation has been reported in the Black Sea (Jørgensen et al, ; Yilmaz et al, ), in the Cariaco Basin (Taylor et al, ; Tuttle & Jannasch, ), in the Baltic Sea (Jost et al, ), in Mariager fjord (Zopfi et al, ), in Namibian shelf waters (Lavik et al, ), and in the oxygen minimum zones of the Eastern Tropical South Pacific (Schunck et al, ). In most cases, a light scattering (particulate) maximum coincides with elevated microbial biomass in the upper portion of the sulfidic zone (Taylor et al, ; Yilmaz et al, ) where sulfur‐oxidizing bacteria have been identified (Glaubitz et al, ; Jørgensen et al, ; Kirkpatrick et al, ; Tuttle & Jannasch, ; Zopfi et al, ). Modeling geochemical balances that are consistent with measured rates of dark carbon fixation has been challenging (Li et al, ).…”

Section: Introductionmentioning

confidence: 99%

Anomalous δ¹³C in Particulate Organic Carbon at the Chemoautotrophy Maximum in the Cariaco Basin

et al. 2020

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A chemoautotrophy maximum is present in many anoxic basins at the sulfidic layer's upper boundary, but the factors controlling this feature are poorly understood. In 13 of 31 cruises to the Cariaco Basin, particulate organic carbon (POC) was enriched in 13C (δ13CPOC as high as −16‰) within the oxic/sulfidic transition compared to photic zone values (−23 to −26‰). During “heavy” cruises, fluxes of O2 and [NO3− + NO2−] to the oxic/sulfidic interface were significantly lower than during “light” cruises. Cruises with isotopically heavy POC were more common between 2013 and 2015 when suspended particles below the photic zone tended to be nitrogen rich compared to later cruises. Within the chemoautotrophic layer, nitrogen‐rich particles (molar ratio C/N< 10) were more likely to be 13C‐enriched than nitrogen‐poor particles, implying that these inventories were dominated by living cells and fresh detritus rather than laterally transported or extensively decomposed detritus. During heavy cruises, 13C enrichments persisted to 1,300 m, providing the first evidence of downward transport of chemoautotrophically produced POC. Dissolved inorganic carbon assimilation during heavy cruises (n = 3) was faster and occurred deeper than during light cruises (n = 2). Metagenomics data from the chemoautotrophic layer during two cruises support prevalence of microorganisms carrying RuBisCO form II genes, which encode a carbon fixation enzyme that discriminates less against heavy isotopes than most other carbon fixation enzymes, and metatranscriptomics data indicate that higher expression of form II RuBisCO genes during the heavy cruises at depths where essential reactants coexist are responsible for the isotopically heavier POC.

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Surface and mid-water sources of organic carbon by photoautotrophic and chemoautotrophic production in the Black Sea

Cited by 45 publications

References 33 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

Variations in ¹⁴C Reservoir Ages of Black Sea Waters and Sedimentary Organic Carbon During Anoxic Periods: Influence of Photosynthetic Versus Chemoautotrophic Production

Anomalous δ¹³C in Particulate Organic Carbon at the Chemoautotrophy Maximum in the Cariaco Basin

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Surface and mid-water sources of organic carbon by photoautotrophic and chemoautotrophic production in the Black Sea

Cited by 45 publications

References 33 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

Variations in 14C Reservoir Ages of Black Sea Waters and Sedimentary Organic Carbon During Anoxic Periods: Influence of Photosynthetic Versus Chemoautotrophic Production

Anomalous δ13C in Particulate Organic Carbon at the Chemoautotrophy Maximum in the Cariaco Basin

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Variations in ¹⁴C Reservoir Ages of Black Sea Waters and Sedimentary Organic Carbon During Anoxic Periods: Influence of Photosynthetic Versus Chemoautotrophic Production

Anomalous δ¹³C in Particulate Organic Carbon at the Chemoautotrophy Maximum in the Cariaco Basin