Vertical Hydrochemical Structure of the Black Sea

Yakushev, E. V.; Часовников, В. К.; Murray, James; Pakhomova, Svetlana; Подымов, О. И.; Stunzhas, P. A.

doi:10.1007/698_5_088

Cited by 27 publications

(9 citation statements)

References 44 publications

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“…Then the O 2 and Fe fluxes will be

J_{O_{2}} = - D ((), \frac{\partial {normalO}_{2}}{\partial z}) = - α \cdot J_{normalF normale ‐ oxide}

where D is the eddy diffusion coefficient (10 −4 to 10 −5 m 2 s −1 ) and α is a stoichiometric constant. Oxycline thickness in the Black Sea is 30–100 m [ Yakushev et al , ], but it is an unusual system with very strong density stratification. In most of the ocean, including upwelling zones with high O 2 consumption rates, the oxicline spans 200–700 m. At 0.1% PAL [O2] sat ≈ 0.26 µ M .…”

Section: Discussionmentioning

confidence: 99%

Causes and consequences of mid-Proterozoic anoxia

Derry

2015

Geophys. Res. Lett.

126

135

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Evidence for low pO2 and a ferruginous ocean characterize the mid‐Proterozoic (1.8–0.8 Ga). Considerations of redox sources and sinks imply that generation of O2 via organic carbon (Corg) burial must be low to maintain a low pO2 atmosphere for geologically long intervals, yet low oxygen should result in increased Corg preservation. Marine export production must therefore be low to limit Corg burial and O2 generation. Formation of ferrous phosphate can buffer deepwater phosphate (Pi) to levels an order of magnitude or more below those in the modern ocean, limiting export production. Low deepwater Pi is consistent with the hiatus in sedimentary phosphorite deposits during the mid‐Proterozoic, and low pO2 limits formation of sedimentary iron deposits (BIF). We propose that low pO2 was maintained by P limitation resulting from ferrous phosphate buffering. The near‐absence of BIF and phosphorite deposition is direct and indirect consequences of the low pO2, respectively.

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“…Then the O 2 and Fe fluxes will be

J_{O_{2}} = - D ((), \frac{\partial {normalO}_{2}}{\partial z}) = - α \cdot J_{normalF normale ‐ oxide}

Section: Discussionmentioning

confidence: 99%

Causes and consequences of mid-Proterozoic anoxia

Derry

2015

Geophys. Res. Lett.

126

135

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“…Assuming Redfield stoichiometry (Redfield, 1934;Redfield et al, 1963) and a fresh to probably brackish water algal productivity of ca. 105 g-C m À2 yr À1 prior to 8.0 kyrs BP (Arthur and Dean, 1998), the 8% of primary productivity exported to and oxidized in the bottom water would have elevated the concentration of combined-N (NH 4 + , NO 3 À , NO 2 À ) to a level that was only moderately less than the current NH 4 + concentration in the bottom water of 97 lmol L À1 (Yakushev et al, 2008). N-lmol L À1 ¼ ð105 g-C m À2 yr À1 Ä 12 g-C=mol-CÞ Â ð0:08Þ Â ð16 mol-NO 3 À Ä 106 mol-CÞ Â ð106 lmol mol À1 Þ Â ð1:3 kyrsÞ Ä ð2150…”

Section: Early Holocene Bosphorus Water Inputmentioning

confidence: 97%

Holocene and late glacial palaeoceanography and palaeolimnology of the Black Sea: Changing sediment provenance and basin hydrography over the past 20,000years

Piper

Calvert

2011

Geochimica et Cosmochimica Acta

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“…Additional disturbances include small-scale turbulence, which can produce local mixing events (Lass et al, 2003). Thus, the extended suboxic zones characteristic of the Black Sea (Yakushev et al, 2008) are absent in Baltic redoxclines. Nevertheless, 16S rRNA fingerprinting analyses has indicated that MGI Crenarchaeota are also prominent in suboxic zones of the central Baltic Sea .…”

Section: Introductionmentioning

confidence: 99%

Relevance of a crenarchaeotal subcluster related to Candidatus Nitrosopumilus maritimus to ammonia oxidation in the suboxic zone of the central Baltic Sea

et al. 2010

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Marine pelagic redoxclines are areas of enhanced biogeochemical cycling inhabited by distinct functional groups of prokaryotes. In this study, the diversity and abundance of archaeal and bacterial nitrifying populations throughout a pelagic redoxcline in the central Baltic Sea were examined using a suite of molecular methods. 16S rRNA/rRNA gene as well as bacterial and archaeal amoA mRNA/amoA gene fingerprints and clone libraries revealed that the putative nitrifying assemblages consisted solely of one crenarchaeotal subcluster, named GD2, which was closely related to Candidatus Nitrosopumilus maritimus. Neither distinct differences between transcriptand gene-based fingerprints nor pronounced differences in the crenarchaeotal composition throughout the whole redoxcline were detected. The abundance of this GD2 subgroup, as determined by the oligonucleotide probe Cren537 and the newly developed and more specific probe Cren679 showed that GD2 and total crenarchaeotal cell numbers were nearly identical throughout the redoxcline. The highest GD2 abundance (2.3 Â 10 5 cells ml À1 ) occurred in the suboxic zone, accounting for around 26% of total prokaryotic cells. Below the chemocline, GD2 abundance was relatively stable (1.5-1.9 Â 10 5 cells ml À1). Archaeal amoA expression was detected only in the putative nitrification zone and formed a narrow band in the suboxic layer, where ammonium, oxygen, nitrate, nitrite and phosphate concentrations were below 5 lmol l À1. To our knowledge this is the first study to show the dominance of only one crenarchaeotal nitrifying key cluster in a natural habitat. The metabolic properties and survival mechanisms present in this cluster inside and outside the nitrification zone remain to be determined.

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Vertical Hydrochemical Structure of the Black Sea

Cited by 27 publications

References 44 publications

Causes and consequences of mid-Proterozoic anoxia

Causes and consequences of mid-Proterozoic anoxia

Holocene and late glacial palaeoceanography and palaeolimnology of the Black Sea: Changing sediment provenance and basin hydrography over the past 20,000years

Relevance of a crenarchaeotal subcluster related to Candidatus Nitrosopumilus maritimus to ammonia oxidation in the suboxic zone of the central Baltic Sea

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