A decade of dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) measurements in the southwestern Baltic Sea

Yanan Zhao,Hermann W Bange,Cathleen Schlundt,Dennis Booge

doi:10.5194/bg-18-2161-2021

Yanan Zhao, Hermann W Bange + Show 2 more

Open Access

https://doi.org/10.5194/bg-18-2161-2021

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Abstract

Abstract. Dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) were measured at the Boknis Eck Time Series Station (BE, Eckernförde Bay, SW Baltic Sea) during the period February 2009–December 2018. Our results show considerable interannual and seasonal variabilities in the mixed-layer concentrations of DMS, total DMSP (DMSPt) and total DMSO (DMSOt). Positive correlations were found between particulate DMSP (DMSPp) and particulate DMSO (DMSOp) as well as DMSPt and DMSOt in the mixed layer, suggesting a similar source for both compounds. The decreasing long-term trends, observed for DMSPt and DMS in the mixed layer, were linked to the concurrent trend of the sum of 19′-hexanoyloxyfucoxanthin and 19′-butanoyloxy-fucoxanthin, which are the marker pigments of prymnesiophytes and chrysophytes, respectively. Major Baltic inflow (MBI) events influenced the distribution of sulfur compounds due to phytoplankton community changes, and sediment might be a potential source for DMS in the bottom layer during seasonal hypoxia/anoxia at BE. A modified algorithm based on the phytoplankton pigments reproduces the DMSPp : Chl a ratios well during this study and could be used to estimate future surface (5 m) DMSPp concentrations at BE.

Highlights

Dimethyl sulfide (DMS) plays an important role in the sulfur cycle of the Earth’s atmosphere (Lovelock et al, 1972): DMS released from the ocean surface may affect the Earth’s climate by forming atmospheric sulfate aerosols, which, in turn, can backscatter solar radiation and possibly act as cloud condensation nuclei that form clouds
We present a unique and comprehensive time-series study of sulfur compounds (DMS, DMSP and dimethyl sulfoxide (DMSO)) at the Boknis Eck Times Series Station, located in the Eckernförde Bay (SW Baltic Sea), from 2009 to 2018
DMSPp and DMSOp concentrations were generally enhanced in spring and autumn in the mixed layer, following the pattern of chlorophyll a (Chl a)

Summary

Introduction

Dimethyl sulfide (DMS) plays an important role in the sulfur cycle of the Earth’s atmosphere (Lovelock et al, 1972): DMS released from the ocean surface may affect the Earth’s climate by forming atmospheric sulfate aerosols, which, in turn, can backscatter solar radiation and possibly act as cloud condensation nuclei that form clouds. Both processes have a cooling effect on the atmosphere (Charlson et al, 1987; Vogt and Liss, 2009; Wang et al, 2015). The primary loss processes of dissolved DMS include (i) microbial consumption, (ii) photooxidation, (iii) air–sea gas exchange and (iv) vertical export by mixing (Simo, 2004)

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