scholarly journals The oceanic budgets of nickel and zinc isotopes: the importance of sulfidic environments as illustrated by the Black Sea

2016 ◽  
Vol 374 (2081) ◽  
pp. 20150294 ◽  
Author(s):  
Derek Vance ◽  
Susan H. Little ◽  
Corey Archer ◽  
Vyllinniskii Cameron ◽  
Morten B. Andersen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Black Sea ◽  
The Black Sea ◽  
Zinc Isotopes ◽  
Trace Element Chemistry ◽  
Dissolved Species ◽  
Climatic Impacts ◽  
Sulfide Species ◽  
Equilibrium Fractionation

Isotopic data collected to date as part of the GEOTRACES and other programmes show that the oceanic dissolved pool is isotopically heavy relative to the inputs for zinc (Zn) and nickel (Ni). All Zn sinks measured until recently, and the only output yet measured for Ni, are isotopically heavier than the dissolved pool. This would require either a non-steady-state ocean or other unidentified sinks. Recently, isotopically light Zn has been measured in organic carbon-rich sediments from productive upwelling margins, providing a potential resolution of this issue, at least for Zn. However, the origin of the isotopically light sedimentary Zn signal is uncertain. Cellular uptake of isotopically light Zn followed by transfer to sediment does not appear to be a quantitatively important process. Here, we present Zn and Ni isotope data for the water column and sediments of the Black Sea. These data demonstrate that isotopically light Zn and Ni are extracted from the water column, probably through an equilibrium fractionation between different dissolved species followed by sequestration of light Zn and Ni in sulfide species to particulates and the sediment. We suggest that a similar, non-quantitative, process, operating in porewaters, explains the Zn data from organic carbon-rich sediments. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

scholarly journals Sulfurization of dissolved organic matter in the anoxic water column of the Black Sea

2021 ◽  
Vol 7 (25) ◽  
pp. eabf6199
Author(s):  
Gonzalo V. Gomez-Saez ◽  
Thorsten Dittmar ◽  
Moritz Holtappels ◽  
Anika M. Pohlabeln ◽  
Anna Lichtschlag ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Water Column ◽  
Black Sea ◽  
Large Scale ◽  
Global Climate ◽  
The Black Sea ◽  
Sulfur Species ◽  
Reduced Sulfur

Today’s oceans store as much dissolved organic carbon (DOC) in the water column as there is CO2 in the atmosphere, and as such dissolved organic matter (DOM) is an important component of the global carbon cycle. It was shown that in anoxic marine sediments, reduced sulfur species (e.g., H2S) abiotically react with organic matter, contributing to carbon preservation. It is not known whether such processes also contribute to preserving DOM in ocean waters. Here, we show DOM sulfurization within the sulfidic waters of the Black Sea, by combining elemental, isotopic, and molecular analyses. Dissolved organic sulfur (DOS) is formed largely in the water column and not derived from sediments or allochthonous nonmarine sources. Our findings suggest that during large-scale anoxic events, DOM may accumulate through abiotic reactions with reduced sulfur species, having long-lasting effects on global climate by enhancing organic carbon sequestration.

scholarly journals Niche partitioning of bacterial communities along the stratified water column in the Black Sea

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mariia Pavlovska ◽  
Ievgeniia Prekrasna ◽  
Evgen Dykyi ◽  
Andrii Zotov ◽  
Artem Dzhulai ◽  
...  
Keyword(s):  
Water Column ◽  
Black Sea ◽  
Bacterial Communities ◽  
Niche Partitioning ◽  
The Black Sea

scholarly journals A BEM for the Hydrodynamic Analysis of Oscillating Water Column Systems in Variable Bathymetry

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3403 ◽  
Author(s):  
Kostas Belibassakis ◽  
Alexandros Magkouris ◽  
Eugen Rusu
Keyword(s):  
Boundary Element Method ◽  
Water Column ◽  
Black Sea ◽  
Bottom Topography ◽  
The Black Sea ◽  
Device Performance ◽  
Oscillating Water Column ◽  
Energy Potential ◽  
Hydrodynamic Analysis

In this work, a novel Boundary Element Method (BEM) is developed and applied to the investigation of the performance of Oscillating Water Column (OWC) systems, taking into account the interaction of the incident wave field with the bottom topography. The modelling includes the effect of additional upwave walls and barriers used to modify the resonance characteristics of the device and improve its performance as the U-OWC configuration. Numerical results illustrating the effects of depth variation in conjunction with other parameters—such as chamber dimensions as well as the parameters associated with the turbine and power take-off system—on the device performance are presented and discussed. Finally, a case study is presented regarding the potential installation of an OWC in a selected port site in the Black Sea, characterized by a good wave energy potential, on the coast of Romania.

Modeling the distribution of nitrogen species and isotopes in the water column of the Black Sea

2008 ◽  
Vol 111 (1-2) ◽  
pp. 106-124 ◽  
Author(s):  
S.K. Konovalov ◽  
C.A. Fuchsman ◽  
V. Belokopitov ◽  
J.W. Murray
Keyword(s):  
Water Column ◽  
Black Sea ◽  
The Black Sea ◽  
Nitrogen Species

scholarly journals Control of the geomorphology and gas hydrate extent on widespread gas emissions offshore Romania

2017 ◽  
Vol 188 (4) ◽  
pp. 26 ◽  
Author(s):  
Vincent Riboulot ◽  
Antonio Cattaneo ◽  
Carla Scalabrin ◽  
Arnaud Gaillot ◽  
Gwénaël Jouet ◽  
...  
Keyword(s):  
Water Column ◽  
Black Sea ◽  
Gas Hydrate ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
The Black Sea ◽  
North East ◽  
Bottom Simulating Reflectors ◽  
Gas Flares ◽  
Sea Fan

The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon compared with the spatial distribution of gas seeps in the water column and the predicted extent of the gas hydrate stability zone. This analysis provides new evidence of the role of geomorphological setting and gas hydrate extent in controlling the location of the observed gas expulsions and gas flares in the water column. Gas flares are today considered an important source of the carbon budget of the oceans and, potentially, of the atmosphere.

Analytical pyrolysis of suspended particulate organic matter from the Black Sea water column

2006 ◽  
Vol 53 (17-19) ◽  
pp. 1856-1874 ◽  
Author(s):  
Yeşim Çoban-Yıldız ◽  
Daniele Fabbri ◽  
Valentina Baravelli ◽  
Ivano Vassura ◽  
Ayşen Yılmaz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Black Sea ◽  
Particulate Organic Matter ◽  
Sea Water ◽  
The Black Sea ◽  
Analytical Pyrolysis ◽  
Suspended Particulate ◽  
Suspended Particulate Organic Matter
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