Spatial distribution of brominated very short‐lived substances in the eastern Pacific

Liu, Yina; Yvon‐Lewis, S. A.; Thornton, Daniel C. O.; Campbell, Lisa; Bianchi, Thomas S.

doi:10.1002/jgrc.20183

Cited by 16 publications

(22 citation statements)

References 68 publications

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“…CHBr 3 and CH 2 Br 2 have been suggested to have similar sources (Moore et al, 1996;Quack et al, 2007b). However, during our cruise, the correlation between the two compounds was comparatively weak (r s = 0.56), consistent with the findings of Liu et al (2013), who ascribed the weaker correlation of these two compounds to formation in a common ecosystem rather than to the exact same biological sources. Maxima of CH 2 Br 2 were observed in both upwelling regions III and IV, while CHBr 3 was highest in the most southerly upwelling IV (Fig.…”

Section: Halocarbon Distribution In Surface Watersupporting

confidence: 87%

“…These values are low in comparison to 44.7 pmol L −1 CHBr 3 in tropical upwelling systems in the Atlantic, while our measurements of CH 2 Br 2 compare better to these upwelling systems, from which maximum concentrations of 9.4 pmol L −1 were reported (Quack et al, 2007a;Carpenter et al, 2009;Hepach et al, 2014Hepach et al, , 2015. CHBr 3 (0.2-20.7 pmol L −1 ) and CH 2 Br 2 (0.7-6.5 pmol L −1 ) concentrations in the tropical eastern Pacific open-ocean and Chilean coastal waters during a cruise from Punta Arenas, Chile, to Seattle, USA, in April 2010 (Liu et al, 2013) compare well with our data. The most elevated concentrations measured at the Chilean coast agree with our elevated northern coastal data.…”

Section: Halocarbon Distribution In Surface Watermentioning

confidence: 66%

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Biogenic halocarbons from the Peruvian upwelling region as tropospheric halogen source

et al. 2016

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Abstract. Halocarbons are produced naturally in the oceans by biological and chemical processes. They are emitted from surface seawater into the atmosphere, where they take part in numerous chemical processes such as ozone destruction and the oxidation of mercury and dimethyl sulfide. Here we present oceanic and atmospheric halocarbon data for the Peruvian upwelling zone obtained during the M91 cruise onboard the research vessel METEOR in December 2012. Surface waters during the cruise were characterized by moderate concentrations of bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ) correlating with diatom biomass derived from marker pigment concentrations, which suggests this phytoplankton group is a likely source. Concentrations measured for the iodinated compounds methyl iodide (CH 3 I) of up to 35.4 pmol L −1 , chloroiodomethane (CH 2 ClI) of up to 58.1 pmol L −1 and diiodomethane (CH 2 I 2 ) of up to 32.4 pmol L −1 in water samples were much higher than previously reported for the tropical Atlantic upwelling systems. Iodocarbons also correlated with the diatom biomass and even more significantly with dissolved organic matter (DOM) components measured in the surface water. Our results suggest a biological source of these compounds as a significant driving factor for the observed large iodocarbon concentrations. Elevated atmospheric mixing ratios of CH 3 I (up to 3.2 ppt), CH 2 ClI (up to 2.5 ppt) and CH 2 I 2 (3.3 ppt) above the upwelling were correlated with seawater concentrations and high sea-to-air fluxes. During the first part of the cruise, the enhanced iodocarbon production in the Peruvian upwelling contributed significantly to tropospheric iodine levels, while this contribution was considerably smaller during the second part.

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Section: Halocarbon Distribution In Surface Watersupporting

confidence: 87%

Section: Halocarbon Distribution In Surface Watermentioning

confidence: 66%

Biogenic halocarbons from the Peruvian upwelling region as tropospheric halogen source

et al. 2016

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“…Numerous efforts have been made to understand the relationship between CHBr 3 production and photosynthetic biomass [ Abrahamsson et al ., ; Karlsson et al ., ; Liu et al ., ; Mattson et al ., ; Quack et al ., ; Raimund et al ., ; Roy , ]. Schall et al .…”

Section: Resultsmentioning

confidence: 98%

“…[]. Details of the analytical method are described in [ Liu et al ., ], following the analytical configuration described in Chen et al . [].…”

Section: Methodsmentioning

confidence: 99%

Spatial and temporal distributions of bromoform and dibromomethane in the Atlantic Ocean and their relationship with photosynthetic biomass

et al. 2013

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[1] Atmospheric mixing ratios and seawater concentrations of bromoform (CHBr 3 ), dibromomethane (CH 2 Br 2 ), and other brominated very short-lived substances (BrVSLS) were measured during five cruises from 1994 to 2010. These cruises were conducted over large latitudinal (62 N-60 S) and longitudinal transects (11 W-86 W) in the Atlantic Ocean. Elevated seawater concentrations of CHBr 3 and CH 2 Br 2 were often observed in regions where chlorophyll a concentrations were also elevated, which suggests biogeochemical processes associated with photosynthetic biomass may be related to CHBr 3 and CH 2 Br 2 production. Our results suggest that, at least in the open ocean, several phytoplankton taxa may contribute to the production of these trace gases. While observed correlations between CHBr 3 and CH 2 Br 2 in different regions are usually interpreted as common sources for these compounds, results in this study suggest different biogeochemical processes may contribute separately to the production of these trace gases. Heterotrophic bacterial abundance was significantly correlated with CH 2 Br 2 , but not with CHBr 3 , which suggests the biogeochemical processes associated with heterotrophic bacteria may be related to CH 2 Br 2 in seawater but probably not to CHBr 3 . In general, the Atlantic Ocean is a net source for CHBr 3 and CH 2 Br 2 , except for a few locations where these trace gases were undersaturated in seawater. Assuming fluxes measured in the Atlantic open ocean are globally representative, the resulting extrapolated, global open-ocean annual net sea-to-air fluxes calculated from data from the five cruises was estimated at 0.24-3.80 Gmol Br yr À1 for CHBr 3 and 0.11-0.77 Gmol Br yr À1 for CH 2 Br 2 .

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“…Depth profiles of the different compounds provide insight into the processes participating in their cycling. Elevated concentrations of CHBr 3 and CH 2 Br 2 at the bottom of the mixed layer and below, often close to the chlorophyll a (Chl a) subsurface maximum, are a common feature in the water column (Yamamoto et al, 2001;Quack et al, 2004;Liu et al, 2013a), and are attributed to enhanced production by phytoplankton. While occasionally CH 3 I maxima close to the Chl a maximum were observed as well (Moore and Groszko, 1999;Wang et al, 2009), Happell and Wallace (1996) ascribed surface maxima in several oceanic regions including the equatorial Atlantic to a predominantly photochemical source.…”

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

confidence: 99%

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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Spatial distribution of brominated very short‐lived substances in the eastern Pacific

Cited by 16 publications

References 68 publications

Biogenic halocarbons from the Peruvian upwelling region as tropospheric halogen source

Biogenic halocarbons from the Peruvian upwelling region as tropospheric halogen source

Spatial and temporal distributions of bromoform and dibromomethane in the Atlantic Ocean and their relationship with photosynthetic biomass

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

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