Stable isotope studies of the carbon, nitrogen and sulfur cycles in the Black Sea and the Cariaco Trench

Fry, Brian; Jannasch, Holger W.; Molyneaux, Stephen J.; Wirsen, Carl O.; Muramoto, Jo Ann; King, Stephen

doi:10.1016/s0198-0149(10)80021-4

Cited by 219 publications

(130 citation statements)

References 44 publications

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“…Although the isotopic signal of sinking photosynthetic organic matter should reflect its origin, the sinking organic matter associated with the oxycline had a different isotopic C signal (reaching values as light as −28.6‰) compared to those observed in the photic layer (reaching values as heavy as −16.9‰). The distinct isotopic composition of the oxycline was possibly associated with chemolithoautotrophic organisms whose presence generally resulted in greater use of the lighter isotope and, as a result, a more negative isotopic composition of the chemosynthetically produced C compared to that C of photosynthetic origin (Fry et al, 1991;Hayes, 2001). According to the above, the observed vertical pattern (see Fig.…”

Section: What Is the Relative Importance Of Chemo-vs Photoautotrophimentioning

confidence: 82%

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N2O and CH4 in an upwelling ecosystem

Farı́as¹,

Fernández

Faúndez³

et al. 2009

Biogeosciences

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Abstract. The high availability of electron donors occurring in coastal upwelling ecosystems with marked oxyclines favours chemoautotrophy, in turn leading to high N 2 O and CH 4 cycling associated with aerobic NH + 4 (AAO) and CH 4 oxidation (AMO). This is the case of the highly productive coastal upwelling area off central Chile (36 • S), where we evaluated the importance of total chemolithoautotrophic vs. photoautotrophic production, the specific contributions of AAO and AMO to chemosynthesis and their role in gas cycling. Chemolithoautotrophy was studied at a time-series station during monthly (2007)(2008)(2009)) and seasonal cruises (January 2008, September 2008, January 2009) and was assessed in terms of the natural C isotopic ratio of particulate organic carbon (δ 13 POC), total and specific (associated with AAO and AMO) dark carbon assimilation (CA), and N 2 O and CH 4 cycling experiments. At the oxycline, δ 13 POC averaged −22.2‰; this was significantly lighter compared to the surface (−19.7‰) and bottom layers (−20.7‰). Total integrated dark CA in the whole water column fluctuated between 19.4 and 2.924 mg C m −2 d −1 , was higher during active upwelling, and contributed 0.7 to 49.7% of the total integrated autotrophic CA (photo plus chemoautotrophy), which ranged from 135 to 7.626 mg C m −2 d −1 , and averaged 20.3% for the whole sampling period. Dark CA was reduced by 27 to 48% after adding a specific AAO inhibitor (ATU) and by 24 to 76% with GC7, a specific archaea inhibitor. This indicates that AAO and AMO microbes (most of them archaea) were performing dark CA through the oxidation of NH

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Section: What Is the Relative Importance Of Chemo-vs Photoautotrophimentioning

confidence: 82%

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N2O and CH4 in an upwelling ecosystem

Farı́as¹,

Fernández

Faúndez³

et al. 2009

Biogeosciences

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“…Sediment proto-kerogen δ 13 C values (-20 to -18‰, Fry et al, 1991) are a good match for particles, suggesting that this OM should be derived from the water column. Proto-kerogen sulfur, however, is much more 34 S-depleted in sediments than in sinking particles.…”

Section: Water Column Sources Of Organic S To Sedimentary Proto-kerogenmentioning

confidence: 86%

Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

Raven

Sessions

Adkins

et al. 2016

Geochimica et Cosmochimica Acta

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Organic matter (OM) burial in marine sediments is a potentially important control on global climate and the long-term redox state of the earth's surface. Still, we have only a limited understanding of the processes that stabilize OM and facilitate its preservation in the geologic record. Abiotic reactions with (poly)sulfides can enhance the preservation potential of OM, but for this process to be significant it needs to compete with OM remineralization, the majority of which occurs before sinking particles reach the sea floor. Here we investigate whether OM sulfurization occurs within sinking particles in the Cariaco Basin, a modern sulfidic marine environment with high rates of OM burial.Proto-kerogen in sinking particles is frequently more sulfur-rich and 34 S-depleted than expectations for biomass, with a composition that is difficult to explain by mixing with resuspended or terrigenous material. Instead, it appears that sulfur is being incorporated into OM on a timescale of days in sinking particles. The flux of this abiogenic organic S from particles is equivalent to approximately two-thirds of the total amount of protokerogen S at 10 cm depth in underlying sediments (ODP Core 1002B); after 6000 years of more gradual sulfurization reactions, potential water column sources are still equivalent to nearly half of the total proto-kerogen S in Cariaco sediments. Water column sulfurization is most extensive during periods of upwelling and high primary productivity 2 and appears to involve elemental S, possibly via polysulfides. This process has the potential to deliver large amounts of OM to the sediments by making it less available for remineralization, generating OM-rich deposits. It represents a potentially dynamic sink in the global carbon cycle that can respond to changes in environmental conditions, including the size and intensity of O 2 -depleted environments. Water column OM sulfurization could also have played a more significant role in the carbon cycle during ocean anoxic events, for example during the Cretaceous.

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“…2) stimulated intensive microbial sulfate reduction (MSR). When heterotrophic organisms such as sulfate reducing microbes (BSM) decompose the organic matter sinking into the stratified anoxic deep water, an isotopically light DIC repository forms (Fry et al, 1991;Velinsky and Fogel, 1999), and at the same time ammonia, free H 2 S and phosphorus are released as well [sulfate reduction: (CH 2 O) 106 (NH 3 ) 16 H 3 PO 4 + 53SO 4 2− = 106CO 2 + 54S 2− + 16NH 3 + 106H 2 O + H 3 PO 4 ] (Jenkyns et al, 2001) (Fig. 6b).…”

Section: Cambrian Stagementioning

confidence: 99%

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Wang

Struck

Guo

et al. 2015

Precambrian Research

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Stable isotope studies of the carbon, nitrogen and sulfur cycles in the Black Sea and the Cariaco Trench

Cited by 219 publications

References 44 publications

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem

Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

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Stable isotope studies of the carbon, nitrogen and sulfur cycles in the Black Sea and the Cariaco Trench

Cited by 219 publications

References 44 publications

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; in an upwelling ecosystem

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; in an upwelling ecosystem

Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

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Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem