Oceanic emissions unlikely to account for the missing source of atmospheric carbonyl sulfide

Abstract. The climate active trace-gas carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere. A missing source in its atmospheric budget is currently suggested, resulting from an upward revision of the vegetation sink in top-down approaches. Oceanic emissions have been proposed to close the resulting gap in the atmospheric budget. We present a bottom-up approach including new observations of OCS in surface waters of the tropical Atlantic, Pacific and Indian oceans to show that direct OCS emissions are insufficient to account for the missing source. Extrapolation of our observations using a biogeochemical box model suggests oceanic net uptake instead of emission for the entire tropical ocean area and, further, a global ocean source strength well below that suggested by top-down estimates. This bottom-up estimate of oceanic emissions has implications for using OCS as a proxy for terrestrial CO2 uptake, which is currently hampered by the inadequate quantification of atmospheric OCS sources and sinks.

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Direct oceanic emissions unlikely to account for the missing source of atmospheric carbonyl sulfide

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-385-2017 ◽

2017 ◽

Vol 17 (1) ◽

pp. 385-402 ◽

Cited By ~ 15

Author(s):

Sinikka T. Lennartz ◽

Christa A. Marandino ◽

Marc von Hobe ◽

Pau Cortes ◽

Birgit Quack ◽

...

Keyword(s):

Surface Waters ◽

Carbonyl Sulfide ◽

Box Model ◽

Trace Gas ◽

Co2 Uptake ◽

Tropical Ocean ◽

Bottom Up ◽

Sources And Sinks ◽

Indirect Emission ◽

Oceanic Emissions

Abstract. The climate active trace-gas carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere. A missing source in its atmospheric budget is currently suggested, resulting from an upward revision of the vegetation sink. Tropical oceanic emissions have been proposed to close the resulting gap in the atmospheric budget. We present a bottom-up approach including (i) new observations of OCS in surface waters of the tropical Atlantic, Pacific and Indian oceans and (ii) a further improved global box model to show that direct OCS emissions are unlikely to account for the missing source. The box model suggests an undersaturation of the surface water with respect to OCS integrated over the entire tropical ocean area and, further, global annual direct emissions of OCS well below that suggested by top-down estimates. In addition, we discuss the potential of indirect emission from CS2 and dimethylsulfide (DMS) to account for the gap in the atmospheric budget. This bottom-up estimate of oceanic emissions has implications for using OCS as a proxy for global terrestrial CO2 uptake, which is currently impeded by the inadequate quantification of atmospheric OCS sources and sinks.

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A numerical evaluation of global oceanic emissions of α-pinene and isoprene

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-2007-2010 ◽

2010 ◽

Vol 10 (4) ◽

pp. 2007-2015 ◽

Cited By ~ 69

Author(s):

G. Luo ◽

F. Yu

Keyword(s):

Numerical Evaluation ◽

Input Data ◽

Organic Aerosol ◽

Aerosol Formation ◽

Top Down ◽

Mixing Processes ◽

Bottom Up ◽

Phytoplankton Communities ◽

Oceanic Emissions

Abstract. A numerical evaluation of global oceanic emissions of α-pinene and isoprene based on both "bottom-up" and "top-down" methods is presented. We infer that the global "bottom-up" oceanic emissions of α-pinene and isoprene are 0.013 TgC yr−1 and 0.32 TgC yr−1, respectively. By constraining global chemistry model simulations with the shipborne measurement of Organics over the Ocean Modifying Particles in both Hemispheres summer cruise, we derived the global "top-down" oceanic α-pinene source of 29.5 TgC yr−1 and isoprene source of 11.6 TgC yr−1. Both the "bottom-up" and "top-down" values are subject to large uncertainties. The incomplete understanding of the in-situ phytoplankton communities and their range of emission potentials significantly impact the estimated global "bottom-up" oceanic emissions, while the estimated total amounts of the global "top-down" oceanic sources can be influenced by emission parameterizations, model and input data spatial resolutions, boundary layer mixing processes, and the treatments of chemical reactions. The global oceanic α-pinene source and its impact on organic aerosol formation is significant based on "top-down" method, but is negligible based on "bottom-up" approach. Our research highlights the importance of carrying out further research (especially measurements) to resolve the large offset in the derived oceanic organic emission based on two different approaches.

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Marine carbonyl sulfide (OCS) and carbon disulfide (CS<sub>2</sub>): a compilation of measurements in seawater and the marine boundary layer

10.5194/essd-2019-162 ◽

2019 ◽

Author(s):

Sinikka T. Lennartz ◽

Christa A. Marandino ◽

Marc von Hobe ◽

Meinrat O. Andreae ◽

Kazushi Aranami ◽

...

Keyword(s):

Boundary Layer ◽

Carbon Disulfide ◽

Marine Boundary Layer ◽

Carbonyl Sulfide ◽

The Arctic ◽

Co2 Uptake ◽

Aerosol Layer ◽

Spatial And Temporal Patterns ◽

Atmospheric Concentration ◽

Oceanic Emissions

Abstract. Carbonyl sulfide (OCS) and carbon disulfide (CS2) are volatile sulfur gases that are naturally formed in seawater and exchanged with the atmosphere. OCS is the most abundant sulfur gas in the atmosphere, and CS2 is its most important precursor. They have gained interest due to their direct (OCS) or indirect (CS2 via oxidation to OCS) contribution to the stratospheric sulfate aerosol layer. Furthermore, OCS serves as a proxy to constrain terrestrial CO2 uptake by vegetation. Oceanic emissions of both gases contribute a major part to their atmospheric concentration. Here we present a database of previously published and unpublished, mainly ship-borne measurements in seawater and the marine boundary layer for both gases, available at https://doi.pangaea.de/10.1594/PANGAEA.905430 (Lennartz et al., 2019). The database contains original measurements as well as data digitalized from figures in publications from 42 measurement campaigns, i.e. cruises or time series stations, ranging from 1982 to 2019. OCS data cover all ocean basins except for the Arctic Ocean, as well as all months of the year, while the CS2 dataset shows large gaps in spatial and temporal coverage. Concentrations are consistent across different sampling and analysis techniques for OCS. The database is intended to support the identification of global spatial and temporal patterns and to facilitate the evaluation of model simulations.

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Marine carbonyl sulfide (OCS) and carbon disulfide (CS<sub>2</sub>): a compilation of measurements in seawater and the marine boundary layer

Earth System Science Data ◽

10.5194/essd-12-591-2020 ◽

2020 ◽

Vol 12 (1) ◽

pp. 591-609 ◽

Cited By ~ 1

Author(s):

Sinikka T. Lennartz ◽

Christa A. Marandino ◽

Marc von Hobe ◽

Meinrat O. Andreae ◽

Kazushi Aranami ◽

...

Keyword(s):

Boundary Layer ◽

Carbon Disulfide ◽

Marine Boundary Layer ◽

Carbonyl Sulfide ◽

The Arctic ◽

Co2 Uptake ◽

Aerosol Layer ◽

Spatial And Temporal Patterns ◽

Atmospheric Concentration ◽

Oceanic Emissions

Abstract. Carbonyl sulfide (OCS) and carbon disulfide (CS2) are volatile sulfur gases that are naturally formed in seawater and exchanged with the atmosphere. OCS is the most abundant sulfur gas in the atmosphere, and CS2 is its most important precursor. They have attracted increased interest due to their direct (OCS) or indirect (CS2 via oxidation to OCS) contribution to the stratospheric sulfate aerosol layer. Furthermore, OCS serves as a proxy to constrain terrestrial CO2 uptake by vegetation. Oceanic emissions of both gases contribute a major part to their atmospheric concentration. Here we present a database of previously published and unpublished (mainly shipborne) measurements in seawater and the marine boundary layer for both gases, available at https://doi.org/10.1594/PANGAEA.905430 (Lennartz et al., 2019). The database contains original measurements as well as data digitalized from figures in publications from 42 measurement campaigns, i.e., cruises or time series stations, ranging from 1982 to 2019. OCS data cover all ocean basins except for the Arctic Ocean, as well as all months of the year, while the CS2 dataset shows large gaps in spatial and temporal coverage. Concentrations are consistent across different sampling and analysis techniques for OCS. The database is intended to support the identification of global spatial and temporal patterns and to facilitate the evaluation of model simulations.

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A numerical evaluation of global oceanic emissions of α-pinene and isoprene

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-20721-2009 ◽

2009 ◽

Vol 9 (5) ◽

pp. 20721-20738

Author(s):

G. Luo ◽

F. Yu

Keyword(s):

Numerical Evaluation ◽

Organic Aerosol ◽

Aerosol Formation ◽

Top Down ◽

Bottom Up ◽

Model Simulations ◽

Oceanic Emissions

Abstract. A numerical evaluation of global oceanic emissions of α-pinene and isoprene based on both "bottom-up" and "top-down" methods is presented. As far as we know, this is the first quantification of global oceanic emission of α-pinene. We infer that the global "bottom-up" oceanic emissions of α-pinene and isoprene are 0.013 Tg C yr−1 and 0.32 Tg C yr−1, respectively. By constraining global chemistry model simulations with the shipboard measurement of Organics over the Ocean Modifying Particles in both Hemispheres summer cruise, we derived the global "top-down" oceanic α-pinene source of 35.1 Tg C yr−1 and isoprene source of 2.5 Tg C yr−1. The global oceanic α-pinene source and its impact on organic aerosol formation is significant based on "top-down" method, but is negligible based on "bottom-up" approach. Our research highlights the importance to carry out further research (especially measurements) to resolve the large offset in the derived oceanic organic emission based on two different approaches.

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A kinetic analysis of leaf uptake of COS and its relation to transpiration, photosynthesis and carbon isotope fractionation

Biogeosciences ◽

10.5194/bg-7-333-2010 ◽

2010 ◽

Vol 7 (1) ◽

pp. 333-341 ◽

Cited By ~ 57

Author(s):

U. Seibt ◽

J. Kesselmeier ◽

L. Sandoval-Soto ◽

U. Kuhn ◽

J. A. Berry

Keyword(s):

Carbonyl Sulfide ◽

Trace Gas ◽

Great Promise ◽

Co2 Uptake ◽

Model Framework ◽

Uptake Rates ◽

Simple Kinetic Model ◽

Leaf Level ◽

Global Vegetation ◽

Atmospheric Trace Gas

Abstract. Carbonyl sulfide (COS) is an atmospheric trace gas that holds great promise for studies of terrestrial carbon and water exchange. In leaves, COS follows the same pathway as CO2 during photosynthesis. Both gases are taken up in enzyme reactions, making COS and CO2 uptake closely coupled at the leaf scale. The biological background of leaf COS uptake is a hydrolysis reaction catalyzed by the enzyme carbonic anhydrase. Based on this, we derive and test a simple kinetic model of leaf COS uptake, and relate COS to CO2 and water fluxes at the leaf scale. The equation was found to predict realistic leaf COS fluxes compared to observations from field and laboratory chambers. We confirm that COS uptake at the leaf level is directly linked to stomatal conductance. As a consequence, the ratio of normalized uptake rates (uptake rates divided by ambient mole fraction) for leaf COS and CO2 fluxes can provide an estimate of Ci/Ca, the ratio of intercellular to atmospheric CO2, an important plant gas exchange parameter that cannot be measured directly. The majority of published normalized COS to CO2 uptake ratios for leaf studies on a variety of species fall in the range of 1.5 to 4, corresponding to Ci/Ca ratios of 0.5 to 0.8. In addition, we utilize the coupling of Ci/Ca and photosynthetic 13C discrimination to derive an estimate of 2.8±0.3 for the global mean normalized uptake ratio. This corresponds to a global vegetation sink of COS in the order of 900±100 Gg S yr−1. COS can now be implemented in the same model framework as CO2 and water vapour. Atmospheric COS measurements can then provide independent constraints on CO2 and water cycles at ecosystem, regional and global scales.

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Halocarbon and dimethyl sulphide studies around the Mascarene Plateau

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2004.1485 ◽

2005 ◽

Vol 363 (1826) ◽

pp. 169-185 ◽

Cited By ~ 12

Author(s):

D. Smythe-Wright ◽

S. M. Boswell ◽

C. H. Lucas ◽

A. L. New ◽

M. S. Varney

Keyword(s):

Indian Ocean ◽

Ozone Depletion ◽

Global Ocean ◽

Trace Gas ◽

Published Data ◽

Dimethyl Sulphide ◽

Global Budget ◽

Sources And Sinks ◽

Central Indian Ocean ◽

Present Understanding

Air–sea exchange is thought to be one of the major routes by which halocarbons and dimethyl sulphide reach the troposphere and stratosphere. Once there, in different ways, they participate in chemical reactions that have implications for ozone depletion and climate change. The gases are released by phytoplankton and other algae, but our present understanding of the sources and sinks is insufficient to establish a balanced global budget. Published data suggest that there are regions of coastal and ocean waters that constitute a major source, but, for halocarbons, in other regions the ocean is a net sink. For example, in many open oceanic areas, the rate of degradation of methyl bromide outweighs production. Here we present data from the Central Indian Ocean, a region considered to be low in terms of biological productivity. Little is known about trace–gas release from the Central Indian Ocean and without such data it is impossible to even hazard a guess at the global ocean source to the atmosphere.

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