Production of free and organic iodine by<i>Roseovarius</i>spp.

Fuse, Hiroyuki; Inoue, Hiroyuki; Murakami, Katsuji; Takimura, Osamu; Yamaoka, Yukiho

doi:10.1016/s0378-1097(03)00839-5

Cited by 82 publications

(57 citation statements)

References 34 publications

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“…CH 3 I and CH 2 I 2 has been observed in the field and the laboratory (Manley and Dastoor, 1988;Amachi et al, 2001;Fuse et al, 2003;Amachi, 2008). Large uncertainties regarding the production of halocarbons in the ocean remain.…”

Section: H Hepach Et Al: Halocarbons In the Atlantic Cold Tonguementioning

confidence: 98%

“…4, 5) could indicate similar production and sink processes at depth. Bacterial formation of CH 2 I 2 (Fuse et al, 2003;Amachi et al, 2005) in the upper thermocline could also be an additional source for this compound. Alternatively, CH 2 I 2 may not degrade as quickly as CHBr 3 and CH 3 I in greater depths, which would lead to its accumulation below the mixed layer.…”

Section: Ch 3 I and Ch 2 Imentioning

confidence: 99%

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Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

et al. 2015

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Abstract.Halocarbons from oceanic sources contribute to halogens in the troposphere, and can be transported into the stratosphere where they take part in ozone depletion. This paper presents distribution and sources in the equatorial Atlantic from June and July 2011 of the four compounds bromoform (CHBr 3 ), dibromomethane (CH 2 Br 2 ), methyl iodide (CH 3 I) and diiodomethane (CH 2 I 2 ). Enhanced biological production during the Atlantic Cold Tongue (ACT) season, indicated by phytoplankton pigment concentrations, led to elevated concentrations of CHBr 3 of up to 44.7 and up to 9.2 pmol L −1 for CH 2 Br 2 in surface water, which is comparable to other tropical upwelling systems. While both compounds correlated very well with each other in the surface water, CH 2 Br 2 was often more elevated in greater depth than CHBr 3 , which showed maxima in the vicinity of the deep chlorophyll maximum. The deeper maximum of CH 2 Br 2 indicates an additional source in comparison to CHBr 3 or a slower degradation of CH 2 Br 2 . Concentrations of CH 3 I of up to 12.8 pmol L −1 in the surface water were measured. In contrary to expectations of a predominantly photochemical source in the tropical ocean, its distribution was mostly in agreement with biological parameters, indicating a biological source. CH 2 I 2 was very low in the near surface water with maximum concentrations of only 3.7 pmol L −1 . CH 2 I 2 showed distinct maxima in deeper waters similar to CH 2 Br 2 . For the first time, diapycnal fluxes of the four halocarbons from the upper thermocline into and out of the mixed layer were determined. These fluxes were low in comparison to the halocarbon sea-to-air fluxes. This indicates that despite the observed maximum concentrations at depth, production in the surface mixed layer is the main oceanic source for all four compounds and one of the main driving factors of their emissions into the atmosphere in the ACTregion. The calculated production rates of the compounds in the mixed layer are 34 ± 65 pmol m −3 h −1 for CHBr 3 , 10 ± 12 pmol m −3 h −1 for CH 2 Br 2 , 21 ± 24 pmol m −3 h −1 for CH 3 I and 384 ± 318 pmol m −3 h −1 for CH 2 I 2 determined from 13 depth profiles.

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Section: H Hepach Et Al: Halocarbons In the Atlantic Cold Tonguementioning

confidence: 98%

Section: Ch 3 I and Ch 2 Imentioning

confidence: 99%

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

et al. 2015

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“…The concentrations are a result of production and loss processes, which may partly be temporally and spatially decoupled. Another possible source for CH 3 I involves bacteria (Manley and Dastoor, 1998;Amachi et al, 2001;Fuse et al, 2003) which has not been taken into account during DRIVE. Additionally, Bell et al (2002) suggested that organic precursors from phytoplankton production could be involved in the photochemical formation of CH 3 I in the surface ocean.…”

Section: Oceanic and Atmospheric Ch 3 I As Drivers Of The Regional Anmentioning

confidence: 99%

Drivers of diel and regional variations of halocarbon emissions from the tropical North East Atlantic

et al. 2014

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Abstract. Methyl iodide (CH 3 I), bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ), which are produced naturally in the oceans, take part in ozone chemistry both in the troposphere and the stratosphere. The significance of oceanic upwelling regions for emissions of these trace gases in the global context is still uncertain although they have been identified as important source regions. To better quantify the role of upwelling areas in current and future climate, this paper analyzes major factors that influenced halocarbon emissions from the tropical North East Atlantic including the Mauritanian upwelling during the DRIVE expedition. Diel and regional variability of oceanic and atmospheric CH 3 I, CHBr 3 and CH 2 Br 2 was determined along with biological and physical parameters at six 24 h-stations. Low oceanic concentrations of CH 3 I from 0.1-5.4 pmol L −1 were equally distributed throughout the investigation area. CHBr 3 and CH 2 Br 2 from 1.0 to 42.4 pmol L −1 and to 9.4 pmol L −1 , respectively were measured with maximum concentrations close to the Mauritanian coast. Atmospheric CH 3 I, CHBr 3 , and CH 2 Br 2 of up to 3.3, 8.9, and 3.1 ppt, respectively were detected above the upwelling, as well as up to 1.8, 12.8, and 2.2 ppt at the Cape Verdean coast. While diel variability in CH 3 I emissions could be mainly ascribed to oceanic nonbiological production, no main driver was identified for its emissions over the entire study region. In contrast, biological parameters showed the greatest influence on the regional distribution of sea-to-air fluxes of bromocarbons. The diel impact of wind speed on bromocarbon emissions increased with decreasing distance to the coast. The height of the marine atmospheric boundary layer (MABL) influenced halocarbon emissions via its influence on atmospheric mixing ratios. Oceanic and atmospheric halocarbons correlated well in the study region, and in combination with high oceanic CH 3 I, CHBr 3 and CH 2 Br 2 concentrations, local hot spots of atmospheric halocarbons could solely be explained by marine sources. This conclusion is in contrast to previous studies that hypothesized elevated atmospheric halocarbons above the eastern tropical Atlantic to be mainly originated from the West-African continent.

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“…(α-Proteobacteria), one isolated from marine sediment and another from seawater (Fuse et al, 2003). Organic iodine species, including CH 3 I, CH 2 ClI, CH 2 I 2 , and CHI 3 , were also produced from iodide by these strains, and it was suggested that organic acids in the media or produced by the strains could be the carbon sources for these organo-iodine products.…”

Section: Microbiological Oxidation Of Iodinementioning

confidence: 99%