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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 Here we present a database of previously published and unpublished (mainly shipborne) measurements in seawater and the marine boundary layer for both gases, available at https://doi.org/10.1594/PANGAEA.905430 (Lennartz et al.,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.

Special issue Microbial Community Structure and Metabolic Networks in Polar Areas.-- 20 pages, 5 figures, 2 tables, supplementary material, We explored how changes of viral abundance and community composition among four contrasting regions in the Southern Ocean relied on physicochemical and microbiological traits. During January–February 2015, we visited areas north and south of the South Orkney Islands (NSO and SSO) characterized by low temperature and salinity and high inorganic nutrient concentration, north of South Georgia Island (NSG) and west of Anvers Island (WA), which have relatively higher temperatures and lower inorganic nutrient concentrations. Surface viral abundance (VA) was highest in NSG (21.50 ± 10.70 × 106 viruses mL−1) and lowest in SSO (2.96 ± 1.48 × 106 viruses mL−1). VA was positively correlated with temperature, prokaryote abundance and prokaryotic heterotrophic production, chlorophyll a, diatoms, haptophytes, fluorescent organic matter, and isoprene concentration, and was negatively correlated with inorganic nutrients (NO3−, SiO42−, PO43−), and dimethyl sulfide (DMS) concentrations. Viral communities determined by randomly amplified polymorphic DNA–polymerase chain reaction (RAPD-PCR) were grouped according to the sampling location, being more similar within them than among regions. The first two axes of a canonical correspondence analysis, including physicochemical (temperature, salinity, inorganic nutrients—NO3−, SiO42−, and dimethyl sulfoniopropionate -DMSP- and isoprene concentrations) and microbiological (chlorophyll a, haptophytes and diatom, and prokaryote abundance and prokaryotic heterotrophic production) factors accounted for 62.9% of the variance. The first axis, temperature-related, accounted for 33.8%; the second one, salinity-related, accounted for 29.1%. Thus, different environmental situations likely select different hosts for viruses, leading to distinct viral communities, The study was supported by the Spanish Ministry of Economy through projects PEGASO (CTM2012-37615) to R. Simó, and BIO-NUC (CGL2013-49020-R) to M. Dall’Osto, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

10 pages, 4 figures, supporting information https://doi.org/10.1029/2020GL087888.-- Data are available at the Zenodo repository (https://doi.org/10.5281/zenodo.3822547, DOI: 10.5281/zenodo.3822547), Isoprene produced by marine phytoplankton acts as a precursor of secondary organic aerosol and thereby affects cloud formation and brightness over the remote oceans. Yet the marine isoprene emission is poorly constrained, with discrepancies among estimates that reach 2 orders of magnitude. Here we present ISOREMS, the first satellite‐only based algorithm for the retrieval of isoprene concentration in the Southern Ocean. Sea surface concentrations from six cruises were matched with remotely sensed variables from MODIS Aqua, and isoprene was best predicted by multiple linear regression with chlorophyll a and sea surface temperature. Climatological (2002–2018) isoprene distributions computed with ISOREMS revealed high concentrations in coastal and near‐island waters, and within the 40–50°S latitudinal band. Isoprene seasonality paralleled phytoplankton productivity, with annual maxima in summer. The annual Southern Ocean emission of isoprene was estimated at 63 Gg C yr−1. The algorithm can provide spatially and temporally realistic inputs to atmospheric and climate models, This research was funded by the Spanish Ministry of Economy and Competitiveness through projects PEGASO (CTM2012‐37615) and BIOGAPS (CTM2016‐81008‐R) to R. S., and partially by the Australian Government through the Australian Research Council's Discovery Projects funding scheme (project DP160103387). The Antarctic Circumnavigation Expedition was made possible by funding from the Swiss Polar Institute and Ferring Pharmaceuticals. P. R. R. was supported by a “la Caixa” Foundation PhD Fellowship (2015-2019), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Special issue The Interrelationships between Near-Surface Ecological Processes and Air–Sea Exchange of Gases and Particles.-- 19 figures, 5 figures, 2 tables, 2 appendices.-- Data of this work can be found at the Zenodo repository (https://doi.org/10.5281/zenodo.3773972).-- This research is part of POLARCSIC (https://polarcsic.es/) activities, soprene is a biogenic trace gas produced by terrestrial vegetation and marine phytoplankton. In the remote oceans, where secondary aerosols are mostly biogenic, marine isoprene emissions affect atmospheric chemistry and influence cloud formation and brightness. Here, we present the first compilation of new and published measurements of isoprene concentrations in the Southern Ocean and explore their distribution patterns. Surface ocean isoprene concentrations in November through April span 1 to 94 pM. A band of higher concentrations is observed around a latitude of ≈40 ∘ S and a surface sea temperature of 15 ∘ C. High isoprene also occurs in high productivity waters near islands and continental coasts. We use concurrent measurements of physical, chemical, and biological variables to explore the main potential drivers of isoprene concentration by means of paired regressions and multivariate analysis. Isoprene is best explained by phytoplankton-related variables like the concentrations of chlorophyll-a, photoprotective pigments and particulate organic matter, photosynthetic efficiency (influenced by iron availability), and the chlorophyll-a shares of most phytoplankton groups, and not by macronutrients or bacterial abundance. A simple statistical model based on chlorophyll-a concentration and a sea surface temperature discontinuity accounts for half of the variance of isoprene concentrations in surface waters of the Southern Ocean, This research was supported by the Spanish Ministry of Economy and Competitiveness through project PEGASO (CTM2012–37615) to RS, and by the Swiss Polar Institute and Ferring Pharmaceuticals through project SORPASSO–ACE#8 to RS and project ACE#1 to David Antoine (Remote Sensing and Satellite Research Group, Curtin University) and Sandy Thomalla (Southern Ocean Carbon and Climate Observatory, Council for Scientific and Industrial Research (CSIR) and Marine Research Institute, University of Cape Town). It was also partially funded by the Australian Government through the Australian Research Council’s Discovery Projects funding scheme (project DP160103387) and South African CSIR Parliamentary Grant (SNA2011112600001). Project ACE#1 was also supported by CSIR Southern Ocean Carbon and Climate Observatory (SOCCO) programme. PRR was supported by a “la Caixa” Foundation PhD Fellowship (2015–2019), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

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.

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.