Concentrations of dissolved dimethyl sulfide (DMS), methanethiol and other trace gases in context of microbial communities from the temperate Atlantic to the Arctic Ocean

Abstract

Abstract. Dimethyl sulfide (DMS) plays an important role in the atmosphere by influencing the formation of aerosols and cloud condensation nuclei. In contrast, the role of methanethiol (MeSH) for the budget and flux of reduced sulfur remains poorly understood. In the present study, we quantified DMS and MeSH together with the trace gases carbon monoxide (CO), isoprene, acetone, acetaldehyde and acetonitrile in North Atlantic and Arctic Ocean surface waters, covering a transect from 57.2 to 80.9∘ N in high spatial resolution in May–June 2015. Whereas isoprene, acetone, acetaldehyde and acetonitrile concentrations decreased northwards, CO, DMS and MeSH retained substantial concentrations at high latitudes, indicating specific sources in polar waters. DMS was the only compound with a higher average concentration in polar (31.2 ± 9.3 nM) than in Atlantic waters (13.5 ± 2 nM), presumably due to DMS originating from sea ice. At eight sea-ice stations north of 80∘ N, in the diatom-dominated marginal ice zone, DMS and chlorophyll a markedly correlated (R2 = 0.93) between 0–50 m depth. In contrast to previous studies, MeSH and DMS did not co-vary, indicating decoupled processes of production and conversion. The contribution of MeSH to the sulfur budget (represented by DMS + MeSH) was on average 20 % (and up to 50 %) higher than previously observed in the Atlantic and Pacific oceans, suggesting MeSH as an important source of sulfur possibly emitted to the atmosphere. The potential importance of MeSH was underlined by several correlations with bacterial taxa, including typical phytoplankton associates from the Rhodobacteraceae and Flavobacteriaceae families. Furthermore, the correlation of isoprene and chlorophyll a with Alcanivorax indicated a specific relationship with isoprene-producing phytoplankton. Overall, the demonstrated latitudinal and vertical patterns contribute to understanding how concentrations of central marine trace gases are linked with chemical and biological dynamics across oceanic waters.

The sensitivity of Southern Ocean atmospheric dimethyl sulfide (DMS) to modeled oceanic DMS concentrations and emissions

“…Using the Anderson et al (2001) parameterization in MODIS-DMS, we determined a large R 2 of 0.75 in the Southern Ocean. While associating chl a with oceanic DMS has discrepancies (Gros et al, 2023;Bell et al, 2021), we show that using Anderson et al (2001) with satellite chl a data better represents Southern Ocean summertime DMS compared with the MEDUSA configuration.…”

“…Previous correlations between chl a and oceanic DMS, given by the coefficient of determination (R 2 ), range globally from 0.11 to 0.93, with higher latitudes having increased R 2 values due to factors like nutrient availability and prolonged summer daylight, coupled with heightened wind speeds (Uhlig et al, 2019;Townsend and Keller, 1996;Tison et al, 2010;Matrai et al, 1993). Gros et al (2023) estimated an R 2 of 0.93 towards sea ice latitudes, while Bell et al (2021) found chl a explains just 15 % of oceanic DMS variability. Using the Anderson et al (2001) parameterization in MODIS-DMS, we determined a large R 2 of 0.75 in the Southern Ocean.…”

The Arctic summer microbiome across Fram Strait: Depth, longitude, and substrate concentrations structure microbial diversity in the euphotic zone

“…Cand . Puniceispirillum and Pseudofulvibacter (Figure 7B) were probably sustained by decaying phytoplankton (Choi et al, 2015; Gros et al, 2023), whereas Chitinophagales and Oligoflexales might utilize chitinous aggregates (Fontanez et al, 2015; Li et al, 2021; Martínez‐García et al, 2022). Aureispira can be attached to gel particles, and feed on bacterial cells or cell debris (Furusawa et al, 2015; Bunse et al, 2021).…”

Carbon monoxide (CO) cycling in the Fram Strait, Arctic Ocean

“…Tran et al (2013) reported a mean CO concentration of 6.5 ± 3.2 nmol L −1 in polar waters of the Fram Strait in July 2010. And only recently Gros et al (2023) reported mean CO concentrations in the range from 1.5 ± 1.7 (in surface waters at sea-ice stations) to 5.9 ± 2.9 nmol L −1 (in polar waters) from the Fram Strait in May-June 2015. CO concentrations decreased with time in all dark incubations, with the exception of pH2 at NT6A (Figs.…”