Production of methyl bromide and methyl chloride in laboratory cultures of marine phytoplankton II

Scarratt, Michael; Moore, Robert M.

doi:10.1016/s0304-4203(97)00092-3

Cited by 84 publications

(61 citation statements)

References 22 publications

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“…Thus we suggest that photochemistry and biological production likely both played a role during MSM18/3. Haptophytes correlated most significantly of the phytoplankton groups with CH 3 I and have already been shown to produce CH 3 I both in the laboratory (Itoh et al, 1997;Manley and de la Cuesta, 1997;Scarratt and Moore, 1998;Smythe-Wright et al, 2010) and in the field (Abrahamsson et al, 2004b). Correlations during MSM18/3 additionally indicate a possible involvement of dinoflagellates and chrysophytes in the production of methyl iodide ( Table 2).…”

Section: Ch 3 I and Ch 2 Imentioning

confidence: 81%

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: Ch 3 I and Ch 2 Imentioning

confidence: 81%

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

et al. 2015

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“…1E) and CH 3 Cl remained unchanged. Methyl halides are known to be produced in seawater by marine microorganisms (32)(33)(34)(35). Some methyl halides are known to be chemically removed from seawater by nucleophilic attack (36), hydrolysis (37), and bacteria (38)(39)(40).…”

Section: Resultsmentioning

confidence: 99%

Changing concentrations of CO, CH ₄ , C ₅ H ₈ , CH ₃ Br, CH ₃ I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments

Wingenter

Haase

Strutton

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Oceanic iron (Fe) fertilization experiments have advanced the understanding of how Fe regulates biological productivity and air-sea carbon dioxide (CO2) exchange. However, little is known about the production and consumption of halocarbons and other gases as a result of Fe addition. Besides metabolizing inorganic carbon, marine microorganisms produce and consume many other trace gases. Several of these gases, which individually impact global climate, stratospheric ozone concentration, or local photochemistry, have not been previously quantified during an Feenrichment experiment. We describe results for selected dissolved trace gases including methane (CH4), isoprene (C5H8), methyl bromide (CH 3Br), dimethyl sulfide, and oxygen (O2), which increased subsequent to Fe fertilization, and the associated decreases in concentrations of carbon monoxide (CO), methyl iodide (CH 3I), and CO 2 observed during the Southern Ocean Iron Enrichment Experiments. P revious iron (Fe) fertilization experiments have been conducted in the North (1) and equatorial Pacific (2, 3) and in the Southern Ocean (4, 5). The Southern Ocean, the largest of the high-nutrient low-chlorophyll regions, represents 6% of the global ocean and has the potential to enhance carbon sequestration by Fe fertilization (6-9), which could slow carbon dioxide (CO 2 ) accumulation in the atmosphere and potentially help alleviate global warming. Experimental MethodsThe experimental design and other results of the Southern Ocean Iron Enrichment Experiment (SOFeX) are presented in an overview paper (8). Of the two regions fertilized with Fe during SOFeX, we focus here on the region north of the Antarctic Polar Front. An area Ϸ15 ϫ 15 km at 56.2°S, 172.0°W (southeast of New Zealand in the southwest Pacific sector of the Southern Ocean) was fertilized with a solution of acidified iron sulfate (FeSO 4 ) over 48 h to a concentration of Ϸ1.2 ϫ 10 Ϫ9 mol⅐liter Ϫ1 (1.2 nM) beginning on January 12, 2002. The background Fe concentration ([Fe]) was Ϸ0.1 nM. A second (36 h) application of FeSO 4 (Ϸ1.2 nM) ended on January 17. These Fe additions were intended to simulate glacial era concentrations of iron in the Southern Ocean (8, 10). The region, or patch, was allowed time to bloom and then was surveyed over a 50-h period, between February 8 and 10, 4 weeks after the first Fe application. By this time the patch had reached a surface area that was a factor of 10 larger than during the initial Fe addition with iron concentrations in the patch of Ϸ0.3 nM (8). During this survey we approached the patch from the South working our way northeast, while crisscrossing the patch. After the shape and orientation of the patch became apparent [elongated and stretching from the southwest to the northeast (11)], more intensive sampling began along the patch. Observations of fluorescence, the partial pressure of CO 2 in seawater (pCO 2 ) (Fig. 1A), dissolved O 2 (Fig. 1B), chlorophyll, and primary productivity indicated a pronounced change in biological activity in the mixed layer (upper 40-5...

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“…Production processes include direct biological synthesis by phytoplankton, bacteria and macroalgae (Tokarczyk and Moore 1994;Tait and Moore, 1995;Moore et al, 1996;Manley and Cuesta, 1997;Scarratt and Moore, 1998;Amachi et al, 2001;Hughes et al, 2006), and indirect production through reactions between dissolved organic matter and light (Moore and Zafiriou, 1994;Happell and Wallace, 1996;Richter and Wallace, 2004) and/or ozone (Martino et al, 2009). Seawater concentrations of halocarbons are also controlled by a number of loss processes, including hydrolysis and nucleophilic attack (Zafiriou, 1975;Elliott and Rowland, 1993), photolysis (Jones and Carpenter, 2005;Martino et al, 2005) and bacterial assimilation (King and Saltzman, 1997;Goodwin et al, 1998Goodwin et al, , 2001.…”

Section: Introductionmentioning

confidence: 99%

Response of halocarbons to ocean acidification in the Arctic

et al. 2013

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The potential effect of ocean acidification (OA) on seawater halocarbons in the Arctic was investigated during a mesocosm experiment in Spitsbergen in June–July 2010. Over a period of 5 weeks, natural phytoplankton communities in nine ~ 50 m³ mesocosms were studied under a range of pCO₂ treatments from ~ 185 μatm to ~ 1420 μatm. In general, the response of halocarbons to pCO₂ was subtle, or undetectable. A large number of significant correlations with a range of biological parameters (chlorophyll a, microbial plankton community, phytoplankton pigments) were identified, indicating a biological control on the concentrations of halocarbons within the mesocosms. The temporal dynamics of iodomethane (CH₃I) alluded to active turnover of this halocarbon in the mesocosms and strong significant correlations with biological parameters suggested a biological source. However, despite a pCO₂ effect on various components of the plankton community, and a strong association between CH₃I and biological parameters, no effect of pCO₂ was seen in CH₃I. Diiodomethane (CH₂I₂) displayed a number of strong relationships with biological parameters. Furthermore, the concentrations, the rate of net production and the sea-to-air flux of CH₂I₂ showed a significant positive response to pCO₂. There was no clear effect of pCO₂ on bromocarbon concentrations or dynamics. However, periods of significant net loss of bromoform (CHBr₃) were found to be concentration-dependent, and closely correlated with total bacteria, suggesting a degree of biological consumption of this halocarbon in Arctic waters. Although the effects of OA on halocarbon concentrations were marginal, this study provides invaluable information on the production and cycling of halocarbons in a region of the world's oceans likely to experience rapid environmental change in the coming decades

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Production of methyl bromide and methyl chloride in laboratory cultures of marine phytoplankton II

Cited by 84 publications

References 22 publications

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

Changing concentrations of CO, CH ₄ , C ₅ H ₈ , CH ₃ Br, CH ₃ I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments

Response of halocarbons to ocean acidification in the Arctic

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Production of methyl bromide and methyl chloride in laboratory cultures of marine phytoplankton II

Cited by 84 publications

References 22 publications

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

Changing concentrations of CO, CH 4 , C 5 H 8 , CH 3 Br, CH 3 I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments

Response of halocarbons to ocean acidification in the Arctic

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Changing concentrations of CO, CH ₄ , C ₅ H ₈ , CH ₃ Br, CH ₃ I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments