Seasonal variations of volatile organic compounds in the coastal Baltic Sea

Orlikowska, Anna; Schulz–Bull, Detlef E.

doi:10.1071/en09107

Cited by 25 publications

(35 citation statements)

References 47 publications

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“…Light can also influence iodocarbon production indirectly, for example by producing oxidants such as H 2 O 2 to promote oxidation of iodide by haloperoxidases (Hill and Manley, 2009) or by altering the quality of dissolved organic matter. The time series of CH 2 I 2 and CH 2 ClI from very shallow (< 4 m) nearshore waters of the Kattegat, Sweden (Klick, 1992), and the Baltic Sea, Germany (Orlikowska and Schulz-Bull, 2009), showed peaks in April-May and again in September-October, with low concentrations throughout summer. This contrasts with the deeper water columns of Bedford Basin, Funka Bay and the English Channel where concentrations remain elevated throughout summer.…”

Section: Seasonal Variationsmentioning

confidence: 98%

A 3-year time series of volatile organic iodocarbons in Bedford Basin, Nova Scotia: a northwestern Atlantic fjord

Shi

Wallace

2018

Ocean Sci.

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Abstract. We report weekly observations of volatile organic iodocarbons (CH3I, CH2ClI and CH2I2) over the time period May 2015 to December 2017 from four depths in Bedford Basin, a coastal fjord (70 m deep) on the Atlantic coast of Canada. The fjord is subject to wintertime mixing, seasonal stratification and bloom dynamics, subsurface oxygen depletion, local input of freshwater, and occasional intrusions of higher-density water from the adjacent continental shelf. Near-surface concentrations showed strong seasonal and sub-seasonal variability, which is compared with other coastal time series. The vertical variation of CH2I2 and CH2ClI within the upper 10 m is consistent with rapid photolysis of CH2I2. Average annual sea-to-air fluxes (46.7 nmol m−2 day−1) of total volatile organic iodine were similar to those observed in other coastal and shelf time series, and polyiodinated compounds contributed 80 % of the total flux. Fluxes were subject to strong interannual variability (a factor of 2) mainly due to wind speed variability. Near-surface net production of CH3I averaged 1 pmol L−1 day−1 and was similar to rates in the English Channel but an order of magnitude higher than in shallow waters of the Kiel Fjord, Germany, possibly due to higher microbial degradation in the latter. The near-bottom (60 m) time series showed evidence of CH3I production associated with organic matter degradation and a possible “switch” from the production of CH3I via an alkylation pathway to the production of CH2I2 by a haloform-type reaction. Near-bottom CH3I production varied strongly between years but was generally ca. 20 times lower than near-surface production.

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Section: Seasonal Variationsmentioning

confidence: 98%

A 3-year time series of volatile organic iodocarbons in Bedford Basin, Nova Scotia: a northwestern Atlantic fjord

Shi

Wallace

2018

Ocean Sci.

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“…Although CH 2 I 2 is generally assumed to be of biogenic origin in the open ocean (Moore and Tokarczyk, 1993;Yamamoto et al, 2001;Orlikowska and Schulz-Bull, 2009;Hopkins et al, 2013), great uncertainties remain as to which species are involved in its production. During MSM18/3, indications were found for different source species than of the other three compounds (chlorophytes and Prochlorococcus HL).…”

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

confidence: 99%

“…An abiotic formation pathway for halocarbons involving ozone has been found for diiodomethane (CH 2 I 2 ) in the laboratory (Martino et al, 2009). But, its production is generally suggested to be biotic, occurring likely through different species of phytoplankton than are involved in the production of CHBr 3 and CH 2 Br 2 (Moore et al, 1996;Orlikowska and Schulz-Bull, 2009). Additionally, bacterial involvement in the formation of halocarbons…”

Section: Introductionmentioning

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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“…The exact origin of the individual data can be identified from the supplemental information (SI) in Ziska et al (2013). Among other sources listed in Ziska et al (2013), observations from air and seawater of the Atlantic are from Butler et al (2007), Chuck et al (2005), Jones et al (2010), Schall et al (1997), and Wang et al (2009), of the Pacific from Butler et al (2007) and Yokouchi et al (2008), of the Southern Ocean from Abrahamsson et al (2004), Butler et al (2007), Chuck et al (2005), and Yokouchi et al (2008), and of other ocean regions from Archer et al (2007), Orlikowska and Schulz-Bull (2009), and Yokouchi et al (2008).…”

Section: Production Pathway/mentioning

confidence: 99%

Methyl iodide production in the open ocean

Stemmler

Hense²,

Quack

et al. 2014

Biogeosciences

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Production pathways of the prominent volatile organic halogen compound methyl iodide (CH3I) are not fully understood. Based on observations, production of CH3I via photochemical degradation of organic material or via phytoplankton production has been proposed. Additional insights could not be gained from correlations between observed biological and environmental variables or from biogeochemical modeling to identify unambiguously the source of methyl iodide. In this study, we aim to address this question of source mechanisms with a three-dimensional global ocean general circulation model including biogeochemistry (MPIOM-HAMOCC (MPIOM - Max Planck Institute Ocean Model HAMOCC - HAMburg Ocean Carbon Cycle model)) by carrying out a series of sensitivity experiments. The simulated fields are compared with a newly available global data set. Simulated distribution patterns and emissions of CH3I differ largely for the two different production pathways. The evaluation of our model results with observations shows that, on the global scale, observed surface concentrations of CH3I can be best explained by the photochemical production pathway. Our results further emphasize that correlations between CH3I and abiotic or biotic factors do not necessarily provide meaningful insights concerning the source of origin. Overall, we find a net global annual CH3I air-sea flux that ranges between 70 and 260 Gg yr-1. On the global scale, the ocean acts as a net source of methyl iodide for the atmosphere, though in some regions in boreal winter, fluxes are of the opposite direction (from the atmosphere to the ocean). © Author(s) 2014

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Seasonal variations of volatile organic compounds in the coastal Baltic Sea

Cited by 25 publications

References 47 publications

A 3-year time series of volatile organic iodocarbons in Bedford Basin, Nova Scotia: a northwestern Atlantic fjord

A 3-year time series of volatile organic iodocarbons in Bedford Basin, Nova Scotia: a northwestern Atlantic fjord

Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue

Methyl iodide production in the open ocean

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