Identification of the algal dimethyl sulfide–releasing enzyme: A missing link in the marine sulfur cycle

Alcolombri, Uria; Ben‐Dor, Shifra; Feldmesser, Ester; Levin, Yishai; Tawfik, Dan S.; Vardi, Assaf

doi:10.1126/science.aab1586

Cited by 221 publications

(269 citation statements)

References 42 publications

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“…A possible direct release of DMS by intracellular or extracellular DMSP-lyase activity of algae (Niki et al, 2000;Stefels, 2000;Alcolombri et al, 2015) is also disregarded. To the best of our knowledge, no studies as of yet have shown that diatoms, the dominant group of the bottom-ice algal community, possess or use DMSP-lyases.…”

Section: Limitations Of the Present Studymentioning

confidence: 99%

Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

et al. 2017

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Abstract. Sea ice represents an additional oceanic source of the climatically active gas dimethyl sulfide (DMS) for the Arctic atmosphere. To what extent this source contributes to the dynamics of summertime Arctic clouds is, however, not known due to scarcity of field measurements. In this study, we developed a coupled sea ice-ocean ecosystem-sulfur cycle model to investigate the potential impact of bottom-ice DMS and its precursor dimethylsulfoniopropionate (DMSP) on the oceanic production and emissions of DMS in the Arctic. The results of the 1-D model simulation were compared with field data collected during May and June of 2010 in Resolute Passage. Our results reproduced the accumulation of DMS and DMSP in the bottom ice during the development of an ice algal bloom. The release of these sulfur species took place predominantly during the earlier phase of the melt period, resulting in an increase of DMS and DMSP in the underlying water column prior to the onset of an under-ice phytoplankton bloom. Production and removal rates of processes considered in the model are analyzed to identify the processes dominating the budgets of DMS and DMSP both in the bottom ice and the underlying water column. When openings in the ice were taken into account, the simulated sea-air DMS flux during the melt period was dominated by episodic spikes of up to 8.1 µmol m −2 d −1 . Further model simulations were conducted to assess the effects of the incorporation of sea-ice biogeochemistry on DMS production and emissions, as well as the sensitivity of our results to changes of uncertain model parameters of the sea-ice sulfur cycle. The results highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that should be better constrained by new observations.

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Section: Limitations Of the Present Studymentioning

confidence: 99%

Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

et al. 2017

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“…Its primary source is the enzymatic cleavage of dimethylsulfoniopropionate (DMSP), a multifunctional osmolyte that accumulates at high (hundred millimolar) intracellular concentrations in some phytoplankton, especially haptophytes, dinoflagellates and some picoeukaryotes (Stefels et al, 2007). DMSP cleavage is catalyzed by a wide diversity of enzymes, called DMSP lyases, produced by some phytoplankton (Alcolombri et al, 2015) and bacteria (Curson et al, 2011). Breakage of phytoplankton cells through zooplankton grazing, viral attack and autolysis releases DMSP to the algal boundary layer and the dissolved phase and enhances DMS production (Simó, 2004;Stefels et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Galí¹,

Levasseur²,

Devred

et al. 2018

Biogeosciences

117

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Abstract. The marine biogenic gas dimethylsulfide (DMS) modulates climate by enhancing aerosol light scattering and seeding cloud formation. However, the lack of time-and space-resolved estimates of DMS concentration and emission hampers the assessment of its climatic effects. Here we present DMS SAT , a new remote sensing algorithm that relies on macroecological relationships between DMS, its phytoplanktonic precursor dimethylsulfoniopropionate (DMSPt) and plankton light exposure. In the first step, planktonic DMSPt is estimated from satellite-retrieved chlorophyll a and the light penetration regime as described in a previous study . In the second step, DMS is estimated as a function of DMSPt and photosynthetically available radiation (PAR) at the sea surface with an equation of the form: log 10 DMS = α+βlog 10 DMSPt+γ PAR. The two-step DMS SAT algorithm is computationally light and can be optimized for global and regional scales. Validation at the global scale indicates that DMS SAT has better skill than previous algorithms and reproduces the main climatological features of DMS seasonality across contrasting biomes. The main shortcomings of the global-scale optimized algorithm are related to (i) regional biases in remotely sensed chlorophyll (which cause underestimation of DMS in the Southern Ocean) and (ii) the inability to reproduce high DMS / DMSPt ratios in late summer and fall in specific regions (which suggests the need to account for additional DMS drivers). Our work also highlights the shortcomings of interpolated DMS climatologies, caused by sparse and biased in situ sampling. Time series derived from MODIS-Aqua in the subpolar North Atlantic between 2003 and 2016 show wide interannual variability in the magnitude and timing of the annual DMS peak(s), demonstrating the need to move beyond the classical climatological view. By providing synoptic time series of DMS emission, DMS SAT can leverage atmospheric chemistry and climate models and advance our understanding of plankton-aerosol-cloud interactions in the context of global change.

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“…Bacterial production of DMS is not the sole pathway bolstering reservoirs of DMS in marine waters: certain species of autotrophic phytoplankton can also directly cleave DMSP into DMS. Although the particular enzymatic reactions that govern DMSP breakdown are not fully characterized (Todd et al, 2007), most reactions are attributed to DMSP lyases (Alcolombri et al, 2015;Schafer et al, 2010;Stefels et al, 2007). What controls the contribution of either process (autotrophic or heterotrophic DMSP to DMS conversion) in fuelling DMS stocks remains unclear but appears to vary extensively (Lizotte et al, 2012).…”

mentioning

confidence: 99%

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Lizotte¹,

Levasseur²,

Law

et al. 2017

Ocean Sci.

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Abstract. The oceanic frontal region above the Chatham Rise east of New Zealand was investigated during the late austral summer season in February and March 2012. Despite its potential importance as a source of marine-originating and climate-relevant compounds, such as dimethyl sulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP), little is known of the processes fuelling the reservoirs of these sulfur (S) compounds in the water masses bordering the subtropical front (STF). This study focused on two opposing short-term fates of DMSP-S following its uptake by microbial organisms (either its conversion into DMS or its assimilation into bacterial biomass) and has not considered dissolved non-volatile degradation products. Sampling took place in three phytoplankton blooms (B1, B2, and B3) with B1 and B3 occurring in relatively nitraterich, dinoflagellate-dominated subantarctic waters, and B2 occurring in nitrate-poor subtropical waters dominated by coccolithophores. Concentrations of total DMSP (DMSP t ) and DMS were high across the region, up to 160 and 14.5 nmol L −1 , respectively. Pools of DMSP t showed a strong association with overall phytoplankton biomass proxied by chlorophyll a (r s = 0.83) likely because of the persistent dominance of dinoflagellates and coccolithophores, both DMSP-rich taxa. Heterotrophic microbes displayed low S assimilation from DMSP (less than 5 %) likely because their S requirements were fulfilled by high DMSP availability. Rates of bacterial protein synthesis were significantly correlated with concentrations of dissolved DMSP (DMSP d , r s = 0.86) as well as with the microbial conversion efficiency of DMSP d into DMS (DMS yield, r s = 0.84). Estimates of the potential contribution of microbially mediated rates of DMS production (0.1-27 nmol L −1 day −1 ) to the near-surface concentrations of DMS suggest that bacteria alone could not have sustained DMS pools at most stations, indicating an important role for phytoplankton-mediated DMS production. The findings from this study provide crucial information on the distribution and cycling of DMS and DMSP in a critically under-sampled area of the global ocean, and they highlight the importance of oceanic fronts as hotspots of the production of marine biogenic S compounds.

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Identification of the algal dimethyl sulfide–releasing enzyme: A missing link in the marine sulfur cycle

Cited by 221 publications

References 42 publications

Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

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