Oceanic distribution of low-molecular-weight hydrocarbons. Baseline measurements

Swinnerton, J. W.; Lamontagne, R. A.

doi:10.1021/es60092a006

Cited by 93 publications

(36 citation statements)

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“…Investigations by Swinnerton and Lamontagne (1974) (Brooks & Sackett 1973). Thus, the position of the ethylene maximum above the methane maximum we observed might be a common feature that points to distinct processes controlling the concentrations of these hydrocarbons.…”

Section: Discussionmentioning

confidence: 55%

“…Sawada and Totsuka (1986) estimate the global emission of ethylene to be 18-45 Tg a −1 , of which 74% is released from natural and 26% from anthropogenic sources; 11% of the natural emission (2.16-4.95 Tg a −1 ) is from aquatic ecosystems. Their calculation for the ocean is based on data from Swinnerton and Lamontagne (1974) and Lamontagne et al (1975). Recently, the emission of ethylene from the global ocean was calculated to be in the range of 0.89 to 2.17 g Tg a −1 in a study on NMHC including most of the earlier published data .…”

Section: Introductionmentioning

confidence: 99%

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Ethylene and methane in the upper water column of the subtropical Atlantic

et al. 1999

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Abstract. The vertical distributions of ethylene and methane in the upper water column of the subtropical Atlantic were measured along a transect from Madeira to the Caribbean and compared with temperature, salinity, oxygen, nutrients, chlorophyll-a, and dissolved organic carbon (DOC).Methane concentrations between 41.6 and 60.7 nL L −1 were found in the upper 20 m of the water column giving a calculated average flux of methane into the atmosphere of 0.82 µg m −2 h −1 . Methane profiles reveal several distinct maxima in the upper 500 m of the water column and short-time variations which are presumably partly related to the vertical migration of zooplankton.Ethylene concentrations in near surface waters varied in the range of 1.8 to 8.2 nL L −1 . Calculated flux rates for ethylene into the atmosphere were in the range of 0.41 to 1.35 µg m −2 h −1 with a mean of 0.83 µg m −2 h −1 . Maximum concentrations of up to 39.2 nL L −1 were detected directly below the pycnocline in the western Atlantic. The vertical distributions of ethylene generally showed one maximum at the pycnocline (about 100 m depth) where elevated concentrations of chlorophyll-a, dissolved oxygen, and nutrients were also found; no ethylene was detected below 270 m depth. This suggests that ethylene release is mainly related to one, probably phytoplankton associated, source, while for methane, enhanced net production occurs at various depth horizons. For surface waters, a simple correlation between ethylene and chlorophyll-a or DOC concentrations could not be observed. No considerable diurnal variation was observed for the distribution and concentration of ethylene in the upper water column.

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Section: Discussionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Ethylene and methane in the upper water column of the subtropical Atlantic

et al. 1999

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“…Ethylene levels found in nature can exceed the levels used in this study, supporting a role for ethylene in Synechocystis physiology (Abeles et al, 1992). Ethylene is photochemically produced when organics dissolved in aqueous environments are exposed to sunlight (Swinnerton and Linnenbom, 1967;Wilson et al, 1970;Swinnerton and Lamontagne, 1974;Ratte et al, 1993Ratte et al, , 1998. Additionally, these prior studies show that ethylene can diffuse and that ethylene levels vary depending upon various environmental conditions, such as light levels and depth in the water column.…”

Section: Discussionmentioning

confidence: 99%

Ethylene Regulates the Physiology of the Cyanobacterium Synechocystis sp. PCC 6803 via an Ethylene Receptor

2016

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Ethylene is a plant hormone that plays a crucial role in the growth and development of plants. The ethylene receptors in plants are well studied, and it is generally assumed that they are found only in plants. In a search of sequenced genomes, we found that many bacterial species contain putative ethylene receptors. Plants acquired many proteins from cyanobacteria as a result of the endosymbiotic event that led to chloroplasts. We provide data that the cyanobacterium Synechocystis (Synechocystis sp. PCC 6803) has a functional receptor for ethylene, Synechocystis Ethylene Response1 (SynEtr1). We first show that SynEtr1 directly binds ethylene. Second, we demonstrate that application of ethylene to Synechocystis cells or disruption of the SynEtr1 gene affects several processes, including phototaxis, type IV pilus biosynthesis, photosystem II levels, biofilm formation, and spontaneous cell sedimentation. Our data suggest a model where SynEtr1 inhibits downstream signaling and ethylene inhibits SynEtr1. This is similar to the inverse-agonist model of ethylene receptor signaling proposed for plants and suggests a conservation of structure and function that possibly originated over 1 billion years ago. Prior research showed that SynEtr1 also contains a light-responsive phytochrome-like domain. Thus, SynEtr1 is a bifunctional receptor that mediates responses to both light and ethylene. To our knowledge, this is the first demonstration of a functional ethylene receptor in a nonplant species and suggests that that the perception of ethylene is more widespread than previously thought.

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“…Supersaturation of surface waters of the Gulf of Mexico with respect to atmospheric CH 4 has long been known (Swinnerton and Lamontagne, 1974;Brooks et al, 1981). The occurrence of several subsurface maxima in the vertical profiles points to their multiple sources/formative processes such as release of CH 4 (originating from anoxic degradation of organic matter and from seeps or gas hydrates) from shelf sediments, lateral dispersal of CH 4 -rich layers, and in situ production (Brooks et al, 1981).…”

Section: Methanementioning

confidence: 99%

Marine hypoxia/anoxia as a source of CH<sub>4</sub> and N<sub>2</sub>O

Naqvi

Bange

Farı́as³

et al. 2010

Biogeosciences

348

240

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Abstract. We review here the available information on methane (CH 4 ) and nitrous oxide (N 2 O) from major marine, mostly coastal, oxygen (O 2 )-deficient zones formed both naturally and as a result of human activities (mainly eutrophication). Concentrations of both gases in subsurface waters are affected by ambient O 2 levels to varying degrees. Organic matter supply to seafloor appears to be the primary factor controlling CH 4 production in sediments and its supply to (and concentration in) overlying waters, with bottom-water O 2 -deficiency exerting only a modulating effect. High (micromolar level) CH 4 accumulation occurs in anoxic (sulphidic) waters of silled basins, such as the Black Sea and Cariaco Basin, and over the highly productive Namibian shelf. In other regions experiencing various degrees of O 2 -deficiency (hypoxia to anoxia), CH 4 concentrations vary from a few to hundreds of nanomolar levels. Since coastal O 2 -deficient zones are generally very productive and are sometimes located close to river mouths and submarine hydrocarbon seeps, it is difficult to differentiate any O 2 -deficiency-induced enhancement from in situ production of CH 4 in the water column and its inputs through freshwater runoff or seepage from sediments. While the role of bottom-water O 2 -deficiency in CH 4 formation appears to be secondary, even when CH 4 accumulates in O 2 -deficient subsurface waters, methanotrophic activity severely restricts its diffusive efflux to the atmosphere. As a result, an intensification or expansion of coastal O 2 -deficient zones will probably Correspondence to: S. W. A. Naqvi (naqvi@nio.org) not drastically change the present status where emission from the ocean as a whole forms an insignificant term in the atmospheric CH 4 budget. The situation is different for N 2 O, the production of which is greatly enhanced in low-O 2 waters, and although it is lost through denitrification in most suboxic and anoxic environments, the peripheries of such environments offer most suitable conditions for its production, with the exception of enclosed anoxic basins. Most O 2 -deficient systems serve as strong net sources of N 2 O to the atmosphere. This is especially true for coastal upwelling regions with shallow O 2 -deficient zones where a dramatic increase in N 2 O production often occurs in rapidly denitrifying waters. Nitrous oxide emissions from these zones are globally significant, and so their ongoing intensification and expansion is likely to lead to a significant increase in N 2 O emission from the ocean. However, a meaningful quantitative prediction of this increase is not possible at present because of continuing uncertainties concerning the formative pathways to N 2 O as well as insufficient data from key coastal regions.

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Oceanic distribution of low-molecular-weight hydrocarbons. Baseline measurements

Cited by 93 publications

References 5 publications

Ethylene and methane in the upper water column of the subtropical Atlantic

Ethylene and methane in the upper water column of the subtropical Atlantic

Ethylene Regulates the Physiology of the Cyanobacterium Synechocystis sp. PCC 6803 via an Ethylene Receptor

Marine hypoxia/anoxia as a source of CH<sub>4</sub> and N<sub>2</sub>O

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Oceanic distribution of low-molecular-weight hydrocarbons. Baseline measurements

Cited by 93 publications

References 5 publications

Ethylene and methane in the upper water column of the subtropical Atlantic

Ethylene and methane in the upper water column of the subtropical Atlantic

Ethylene Regulates the Physiology of the Cyanobacterium Synechocystis sp. PCC 6803 via an Ethylene Receptor

Marine hypoxia/anoxia as a source of CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O

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Marine hypoxia/anoxia as a source of CH<sub>4</sub> and N<sub>2</sub>O