Novel Insights into Dimethylsulfoniopropionate Catabolism by Cultivable Bacteria in the Arctic Kongsfjorden

2021 ◽  
Author(s):  
Shan Zhang ◽  
Hai-Yan Cao ◽  
Nan Zhang ◽  
Zhao-Jie Teng ◽  
Yang Yu ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Global Climate ◽  
Bioinformatic Analysis ◽  
Sulfur Cycle ◽  
The Arctic ◽  
Catabolic Pathways ◽  
Organic Sulfur Compounds ◽  
Cultivable Bacteria ◽  
Demethylation Pathway ◽  
Biochemical Analyses

Dimethylsulfoniopropionate (DMSP) is one of the most abundant organic sulfur compounds in the oceans, which is mainly degraded by bacteria through two pathways, a cleavage pathway and a demethylation pathway. Its volatile catabolites dimethyl sulfide (DMS) and methanethiol (MT) in these pathways play important roles in the global sulfur cycle and have potential influences on the global climate. Intense DMS/DMSP cycling occurs in the Arctic. However, little is known about the diversity of cultivable DMSP-catabolizing bacteria in the Arctic and how they catabolize DMSP. Here, we screened DMSP-catabolizing bacteria from Arctic samples and found that bacteria of four genera ( Psychrobacter , Pseudoalteromonas , Alteromonas and Vibrio ) could grow with DMSP as the sole carbon source, among which Psychrobacter and Pseudoalteromonas are predominant. Four representative strains ( Psychrobacter sp. K31L, Pseudoalteromonas sp. K222D, Alteromonas sp. K632G and Vibrio sp. G41H) from different genera were selected to probe their DMSP catabolic pathways. All these strains produce DMS and MT simultaneously during their growth on DMSP, indicating that all strains likely possess the two DMSP catabolic pathways. On the basis of genomic and biochemical analyses, the DMSP catabolic pathways in these strains were proposed. Bioinformatic analysis indicated that most bacteria of Psychrobacter and Vibrio have the potential to catabolize DMSP via the demethylation pathway, and that only a small portion of Psychrobacter strains may catabolize DMSP via the cleavage pathway. This study provides novel insights into DMSP catabolism in marine bacteria. IMPORTANCE Dimethylsulfoniopropionate (DMSP) is abundant in the oceans. The catabolism of DMSP is an important step of the global sulfur cycle. Although Gammaproteobacteria are widespread in the oceans, the contribution of Gammaproteobacteria in global DMSP catabolism is not fully understood. Here, we found that bacteria of four genera belonging to Gammaproteobacteria ( Psychrobacter , Pseudoalteromonas , Alteromonas and Vibrio ), which were isolated from Arctic samples, were able to grow on DMSP. The DMSP catabolic pathways of representative strains were proposed. Bioinformatic analysis indicates that most bacteria of Psychrobacter and Vibrio have the potential to catabolize DMSP via the demethylation pathway, and that only a small portion of Psychrobacter strains may catabolize DMSP via the cleavage pathway. Our results suggest that novel DMSP dethiomethylases/demethylases may exist in Pseudoalteromonas , Alteromonas and Vibrio , and that Gammaproteobacteria may be important participants in marine, especially in polar DMSP cycling.

scholarly journals Novel enzyme for dimethyl sulfide-releasing in bacteria reveals a missing route in the marine sulfur cycle

2020 ◽  
Author(s):  
Chun-Yang Li ◽  
Xiu-Juan Wang ◽  
Xiu-Lan Chen ◽  
Qi Sheng ◽  
Shan Zhang ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Catalytic Mechanism ◽  
Global Climate ◽  
Sulfur Cycle ◽  
The Novel ◽  
Key Enzyme ◽  
Biochemical Analyses ◽  
Bacterial Lineages

AbstractDimethylsulfoniopropionate (DMSP) is an abundant and ubiquitous organosulfur molecule and plays important roles in the global sulfur cycle. Cleavage of DMSP produces volatile dimethyl sulfide (DMS), which has impacts on the global climate. Multiple pathways for DMSP catabolism have been identified. Here we identified yet another novel pathway, the ATP DMSP lysis pathway. The key enzyme, AcoD, is an ATP-dependent DMSP lyase. AcoD belongs to the acyl-CoA synthetase superfamily, which is totally different from other DMSP lyases, showing a new evolution route. AcoD catalyses the conversion of DMSP to DMS by a two-step reaction: the ligation of DMSP with CoA to form the intermediate DMSP-CoA, which is then cleaved to DMS and acryloyl-CoA. The novel catalytic mechanism was elucidated by structural and biochemical analyses. AcoD is widely distributed in many bacterial lineages including Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Firmicutes, revealing this new pathway plays important roles in global DMSP/DMS cycles.

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

2017 ◽  
Vol 14 (12) ◽  
pp. 3129-3155 ◽  
Author(s):  
Hakase Hayashida ◽  
Nadja Steiner ◽  
Adam Monahan ◽  
Virginie Galindo ◽  
Martine Lizotte ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Dimethyl Sulfide ◽  
Phytoplankton Bloom ◽  
Model Simulation ◽  
Field Measurements ◽  
Sulfur Cycle ◽  
The Arctic ◽  
Model Parameters ◽  
Ocean Ecosystem

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.

scholarly journals Dimethyl sulfide in the summertime Arctic atmosphere: measurements and source sensitivity simulations

2016 ◽  
Vol 16 (11) ◽  
pp. 6665-6680 ◽  
Author(s):  
Emma L. Mungall ◽  
Betty Croft ◽  
Martine Lizotte ◽  
Jennie L. Thomas ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Transport Model ◽  
Sulfur Cycle ◽  
Oxidation Products ◽  
The Arctic ◽  
High Time Resolution ◽  
Study Region ◽  
Baffin Bay ◽  
Mixing Ratios ◽  
Arctic Atmosphere

Abstract. Dimethyl sulfide (DMS) plays a major role in the global sulfur cycle. In addition, its atmospheric oxidation products contribute to the formation and growth of atmospheric aerosol particles, thereby influencing cloud condensation nuclei (CCN) populations and thus cloud formation. The pristine summertime Arctic atmosphere is strongly influenced by DMS. However, atmospheric DMS mixing ratios have only rarely been measured in the summertime Arctic. During July–August, 2014, we conducted the first high time resolution (10 Hz) DMS mixing ratio measurements for the eastern Canadian Archipelago and Baffin Bay as one component of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). DMS mixing ratios ranged from below the detection limit of 4 to 1155 pptv (median 186 pptv) during the 21-day shipboard campaign. A transfer velocity parameterization from the literature coupled with coincident atmospheric and seawater DMS measurements yielded air–sea DMS flux estimates ranging from 0.02 to 12 µmol m−2 d−1. Air-mass trajectory analysis using FLEXPART-WRF and sensitivity simulations with the GEOS-Chem chemical transport model indicated that local sources (Lancaster Sound and Baffin Bay) were the dominant contributors to the DMS measured along the 21-day ship track, with episodic transport from the Hudson Bay System. After adjusting GEOS-Chem oceanic DMS values in the region to match measurements, GEOS-Chem reproduced the major features of the measured time series but was biased low overall (2–1006 pptv, median 72 pptv), although within the range of uncertainty of the seawater DMS source. However, during some 1–2 day periods the model underpredicted the measurements by more than an order of magnitude. Sensitivity tests indicated that non-marine sources (lakes, biomass burning, melt ponds, and coastal tundra) could make additional episodic contributions to atmospheric DMS in the study region, although local marine sources of DMS dominated. Our results highlight the need for both atmospheric and seawater DMS data sets with greater spatial and temporal resolution, combined with further investigation of non-marine DMS sources for the Arctic.

Sulfur Cycle

2006 ◽  
Author(s):  
Thomas S. Bianchi
Keyword(s):  
Biomass Burning ◽  
Molecular Species ◽  
Dimethyl Sulfide ◽  
Major Ions ◽  
Global Climate ◽  
Biogeochemical Cycling ◽  
Global Scale ◽  
Sulfur Cycle ◽  
Biogeochemical Processes ◽  
Climate Patterns

Sulfur (S) is an important redox element in estuaries because of its linkage with biogeochemical processes such as SO42− reduction (Howarth and Teal, 1979; Jørgensen, 1982; Luther et al., 1986; Roden and Tuttle, 1992, 1993a,b; Miley and Kiene, 2004), pyrite (FeS2) formation (Giblin, 1988; Hsieh and Yang, 1997; Morse and Wang, 1997), metal cycling (Krezel and Bal, 1999; Leal et al., 1999; Tang et al., 2000), ecosystem energetics (King et al., 1982; Howarth and Giblin, 1983; Howes et al., 1984), and atmospheric S emissions (Dacey et al., 1987; Turner et al., 1996; Simo et al., 1997). The range of oxidations for S intermediates formed in each of these processes is between +VI and −II. Many of the important naturally occurring molecular species of S are shown in table 12.1. On a global scale, most of the S is located in the lithosphere; however, there are important interactions between the hydrosphere, biosphere, and atmosphere where important transfers of S occur (Charlson, 2000). For example, coal and biomass burning, along with volcano emissions inject SO2 into the atmosphere, which can then be further oxidized in the atmosphere and removed as SO42− in rainwater (Galloway, 1985). An example of biogenic sulfur formation is the reduction of seawater SO42− to sulfide by phytoplankton and eventual incorporation of the S into dimethylsulfoniopropionate (DMSP). DMSP, in turn, is converted to volatile dimethyl sulfide (DMS; CH3SCH3)m which is emitted to the atmosphere. In the seawater, SO42− represents one of the major ions, with concentrations that range from 24 to 28 mM, which is considerably higher than the concentrations found in freshwaters (∼0.1 mM). This marked difference makes seawater the major input to estuaries and sets up an important gradient in estuarine biogeochemical cycling. In this chapter, the focus will be on the nonanthropogenic biogenic transformations of S that are relevant to biogeochemical cycling in estuarine and coastal waters. Approximately 50% of the global flux of S to the atmosphere is derived from marine emissions of DMS. Oxidation of DMS in the atmosphere leads to production of SO42− aerosols, which can influence global climate patterns (Charlson et al., 1987; Andreae and Crutzen, 1997).

scholarly journals Observation-based selection of climate models projects Arctic ice-free summers around 2035

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
David Docquier ◽  
Torben Koenigk
Keyword(s):  
Model Selection ◽  
Sea Ice ◽  
Climate Models ◽  
Global Climate ◽  
Coupled Model ◽  
Arctic Sea Ice ◽  
Global Climate Models ◽  
The Arctic ◽  
Arctic Sea ◽  
Area And Volume

AbstractArctic sea ice has been retreating at an accelerating pace over the past decades. Model projections show that the Arctic Ocean could be almost ice free in summer by the middle of this century. However, the uncertainties related to these projections are relatively large. Here we use 33 global climate models from the Coupled Model Intercomparison Project 6 (CMIP6) and select models that best capture the observed Arctic sea-ice area and volume and northward ocean heat transport to refine model projections of Arctic sea ice. This model selection leads to lower Arctic sea-ice area and volume relative to the multi-model mean without model selection and summer ice-free conditions could occur as early as around 2035. These results highlight a potential underestimation of future Arctic sea-ice loss when including all CMIP6 models.

scholarly journals Societal implications of a changing Arctic Ocean

AMBIO ◽  
2021 ◽  
Author(s):  
Henry P. Huntington ◽  
Andrey Zagorsky ◽  
Bjørn P. Kaltenborn ◽  
Hyoung Chul Shin ◽  
Jackie Dawson ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Indigenous Peoples ◽  
Global Climate ◽  
Rapid Change ◽  
The Arctic ◽  
Cultural Continuity ◽  
Societal Implications ◽  
Arctic Ecosystems ◽  
The Many

AbstractThe Arctic Ocean is undergoing rapid change: sea ice is being lost, waters are warming, coastlines are eroding, species are moving into new areas, and more. This paper explores the many ways that a changing Arctic Ocean affects societies in the Arctic and around the world. In the Arctic, Indigenous Peoples are again seeing their food security threatened and cultural continuity in danger of disruption. Resource development is increasing as is interest in tourism and possibilities for trans-Arctic maritime trade, creating new opportunities and also new stresses. Beyond the Arctic, changes in sea ice affect mid-latitude weather, and Arctic economic opportunities may re-shape commodities and transportation markets. Rising interest in the Arctic is also raising geopolitical tensions about the region. What happens next depends in large part on the choices made within and beyond the Arctic concerning global climate change and industrial policies and Arctic ecosystems and cultures.

scholarly journals Development of Northern Sea Route: Prospects for International Cooperation

2021 ◽  
Vol 1 (1) ◽  
pp. 67-77
Author(s):  
A. V. Kirgizov-Barskii
Keyword(s):  
Global Climate Change ◽  
Swot Analysis ◽  
Global Climate ◽  
Water Area ◽  
The Arctic ◽  
Northern Coast ◽  
Arctic Zone ◽  
Northern Sea Route ◽  
Transportation Route ◽  
Modern Technologies

Today due to global climate change the Northern Sea Route is being formed along the northern coast of Russia as a new international maritime passage in the Arctic. Due to the rapid increase in the interest of regional and non-Arctic states, the scientific community and business to this transportation route, there is a need to study the prospects for cooperation between Russia and other countries on the development of the Northern Sea Route. The paper provides a detailed analysis of the interests of external players in the NSR area, taking into account the latest changes and events, while the author uses swot-analysis and a comparative analytical approach to conduct the study. The results of the study have shown that cooperation with some Arctic countries on the development of the NSR could bring mutual benefits: Canada and Russia would exchange experience on the development of similar sea routes, and Norway and Iceland would receive advantages as hubs on new routes. Non-regional countries, such as China, South Korea, Japan, Singapore and India, are interested in the NSR. For them, the Northern Sea Route is potentially shorter and safer compared to traditional routes, and it also allows to participate in projects located near its water area in science, energy and transport sectors. In turn, the participation of foreign partners is important for Russia, since it is usually accompanied by the active use of the route, the creation of large projects throughout its entire length, the attraction of serious funds, modern technologies and knowledge to the Arctic zone of the country.

scholarly journals Permafrost-Affected Soils of the Russian Arctic and their Carbon Pools

2014 ◽  
Vol 6 (1) ◽  
pp. 619-655
Author(s):  
S. Zubrzycki ◽  
L. Kutzbach ◽  
E.-M. Pfeiffer
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Sink ◽  
Global Climate ◽  
Fundamental Property ◽  
Climate System ◽  
The Arctic ◽  
Quaternary Period ◽  
Permafrost Regions

Abstract. Permafrost-affected soils have accumulated enormous pools of organic matter during the Quaternary Period. The area occupied by these soils amounts to more than 8.6 million km2, which is about 27% of all land areas north of 50° N. Therefore, permafrost-affected soils are considered to be one of the most important cryosphere elements within the climate system. Due to the cryopedogenic processes that form these particular soils and the overlying vegetation that is adapted to the arctic climate, organic matter has accumulated to the present extent of up to 1024 Pg (1 Pg = 1015 g = 1 Gt) of soil organic carbon stored within the uppermost three meters of ground. Considering the observed progressive climate change and the projected polar amplification, permafrost-affected soils will undergo fundamental property changes. Higher turnover and mineralization rates of the organic matter are consequences of these changes, which are expected to result in an increased release of climate-relevant trace gases into the atmosphere. As a result, permafrost regions with their distinctive soils are likely to trigger an important tipping point within the global climate system, with additional political and social implications. The controversy of whether permafrost regions continue accumulating carbon or already function as a carbon source remains open until today. An increased focus on this subject matter, especially in underrepresented Siberian regions, could contribute to a more robust estimation of the soil organic carbon pool of permafrost regions and at the same time improve the understanding of the carbon sink and source functions of permafrost-affected soils.

scholarly journals Halogenated Greenhouse Gases Made Global Warming Primarily

2022 ◽  
Author(s):  
Qing-Bin Lu
Keyword(s):  
Sea Ice ◽  
Greenhouse Gases ◽  
Land Surface ◽  
Southern Oscillation ◽  
Theoretical Calculations ◽  
Global Climate ◽  
Surface Air Temperature ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Snow Cover Extent

Abstract Time-series observations of global lower stratospheric temperature (GLST), global land surface air temperature (LSAT), global mean surface temperature (GMST), sea ice extent (SIE) and snow cover extent (SCE), together with observations reported in Paper I, combined with theoretical calculations of GLSTs and GMSTs, have provided strong evidence that ozone depletion and global climate changes are dominantly caused by human-made halogen-containing ozone-depleting substances (ODSs) and greenhouse gases (GHGs) respectively. Both GLST and SCE have become constant since the mid-1990s and GMST/LSAT has reached a peak since the mid-2000s, while regional continued warmings at the Arctic coasts (particularly Russia and Alaska) in winter and spring and at some areas of Antarctica are observed and can be well explained by a sea-ice-loss warming amplification mechanism. The calculated GMSTs by the parameter-free warming theory of halogenated GHGs show an excellent agreement with the observed GMSTs after the natural El Niño southern oscillation (ENSO) and volcanic effects are removed. These results provide a convincing mechanism of global climate change and will make profound changes in our understanding of atmospheric processes. This study also emphasizes the critical importance of continued international efforts in phasing out all anthropogenic halogenated ODSs and GHGs.

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