Gas exchange rates between air and sea&lt;sup&gt;1&lt;/sup&gt;

Broecker, Wallace S.; Peng, Tsung‐Hung

doi:10.3402/tellusa.v26i1-2.9733

Cited by 588 publications

(292 citation statements)

References 17 publications

(13 reference statements)

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“…However, a fourth component, disequilibrium carbon (DIC dis ), is also potentially significant as discussed by Ito and Follows (2013). Defined as 10 the difference between preformed DIC and DIC sat , DIC dis can be relatively large (Takahashi et al, 2009) because of the slow timescale of atmosphere-surface ocean equilibrium of carbon compared to other gases, caused by the buffering capacity of seawater (e.g., Zeebe and Wolf-Gladrow, 2001;Broecker and Peng, 1974).…”

Section: Introductionmentioning

confidence: 99%

The devil's in the disequilibrium: sensitivity of ocean carbon storage to climate state and iron fertilization in a general circulation model

Eggleston

Galbraith

2017

Preprint

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Abstract. Ocean dissolved inorganic carbon (DIC) storage can be conceptualized as the sum of four components: saturation (DIC sat ), disequilibrium (DIC dis ), carbonate (DIC carb ) and soft tissue (DIC soft ). Among these, DIC dis and DIC soft have the potential for large changes that are relatively difficult to predict. Here we explore changes in DIC soft and DIC dis in a large suite of simulations with a complex coupled climate-biogeochemical model, driven by changes in orbital forcing, ice sheets and the radiative effect of CO 2 . Both DIC dis and DIC soft vary over a range of 40 µmol/kg in response to the climate forcing, 5 equivalent to changes in atmospheric CO 2 on the order of 50 ppm for each. We find that, despite the broad range of climate states represented, changes in global DIC soft can be well-approximated by the product of deep ocean ideal age and the global export production flux, while global DIC dis is dominantly controlled by the fraction of the ocean filled by Antarctic Bottom Water (AABW). Because the AABW fraction and ideal age are inversely correlated between the simulations, DIC dis and DIC soft are also inversely correlated. This inverse correlation could be decoupled if changes in deep ocean mixing were to alter ideal 10 age independently of AABW fraction, or if independent ecosystem changes were to alter export and remineralization, thereby modifying DIC soft . As an example of the latter, iron fertilization causes DIC soft to increase, and causes DIC dis to also increase by a similar or greater amount, to a degree that depends on climate state. We propose a simple framework to consider the global contribution of DIC soft + DIC dis to ocean carbon storage as a function of the surface preformed nitrate and DIC dis of dense water formation regions, the global volume fractions ventilated by these regions, and the global nitrate inventory. More 15 extensive sea ice increases DIC dis , and when sea ice becomes very extensive it also causes significant O 2 disequilibrium, which may have contributed to reconstructions of low O 2 in the Southern Ocean during the glacial. Global DIC dis reaches a minimum near modern CO 2 because the AABW fraction reaches a minimum, which may have contributed to preventing further CO 2 rise during interglacial periods.

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Section: Introductionmentioning

confidence: 99%

The devil's in the disequilibrium: sensitivity of ocean carbon storage to climate state and iron fertilization in a general circulation model

Eggleston

Galbraith

2017

Preprint

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“…The exchange of many gases and gaseous compounds has been studied using the film model (Broecker and Peng, 1974;Liss, 1973;Liss and Merlivat, 1986). The property of elemental mercury (Hg 0 ) that allows it to be subjected to sea-air gas exchange is unique among heavy metals.…”

Section: Introductionmentioning

confidence: 99%

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

Kuss¹,

Krüger²,

Ruickoldt³

et al. 2017

Preprint

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“…The exchange of many gases and gaseous compounds has been studied using the film model (Broecker and Peng, 1974;Liss, 1973;Liss and Merlivat, 1986). The property of elemental mercury (Hg 0 ) that allows it to be subjected to seaair gas exchange is unique among heavy metals.…”

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confidence: 99%

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

et al. 2018

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Abstract. Marginal seas are directly subjected to anthropogenic and natural influences from land in addition to receiving inputs from the atmosphere and open ocean. Together these lead to pronounced gradients and strong dynamic changes. However, in the case of mercury emissions from these seas, estimates often fail to adequately account for the spatial and temporal variability of the elemental mercury concentration in surface water (Hg 0 wat ). In this study, a method to measure Hg 0 wat at high resolution was devised and subsequently validated. The better-resolved Hg 0 wat dataset, consisting of about one measurement per nautical mile, yielded insight into the sea's small-scale variability and thus improved the quantification of the sea's Hg 0 emission. This is important because global marine Hg 0 emissions constitute a major source of atmospheric mercury.Research campaigns in the Baltic Sea were carried out between 2011 and 2015 during which Hg 0 both in surface water and in ambient air were measured. For the former, two types of equilibrators were used. A membrane equilibrator enabled continuous equilibration and a bottle equilibrator assured that equilibrium was reached for validation. The measurements were combined with data obtained in the Baltic Sea in 2006 from a bottle equilibrator only. The Hg 0 sea-air flux was newly calculated with the combined dataset based on current knowledge of the Hg 0 Schmidt number, Henry's law constant, and a widely used gas exchange transfer velocity parameterization. By using a newly developed pump-CTD with increased pumping capability in the Hg 0 equilibrator measurements, Hg 0 wat could also be characterized in deeper water layers. A process study carried out near the Swedish island Øland in August 2015 showed that the upwelling of Hg 0 -depleted water contributed to Hg 0 emissions of the Baltic Sea. However, a delay of a few days after contact between the upwelled water and light was apparently necessary before the biotic and abiotic transformations of ionic to volatile Hg 0 produced a distinct sea-air Hg 0 concentration gradient.This study clearly showed spatial, seasonal, and interannual variability in the Hg 0 sea-air flux of the Baltic Sea. The average annual Hg 0 emission was 0.90 ± 0.18 Mg for the Baltic proper and extrapolated to 1.73 ± 0.32 Mg for the entire Baltic Sea, which is about half the amount entrained by atmospheric deposition. A comparison of our results with the Hg 0 sea-air fluxes determined in the Mediterranean Sea and in marginal seas in East Asia were to some extent similar but they partly differed in terms of the deviations in the amount and seasonality of the flux.

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Gas exchange rates between air and sea<sup>1</sup>

Cited by 588 publications

References 17 publications

The devil's in the disequilibrium: sensitivity of ocean carbon storage to climate state and iron fertilization in a general circulation model

The devil's in the disequilibrium: sensitivity of ocean carbon storage to climate state and iron fertilization in a general circulation model

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

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