Distribution of dimethylsulfide (DMS) and/or particulate dimethylsulfoniopropionate (DMSPp) concentrations in the Jiaozhou Bay, Zhifu Bay and East China Sea were investigated during the period of 1994 - 1998. Both DMS...Distribution of dimethylsulfide (DMS) and/or particulate dimethylsulfoniopropionate (DMSPp) concentrations in the Jiaozhou Bay, Zhifu Bay and East China Sea were investigated during the period of 1994 - 1998. Both DMS and DMSPp levels showed remarkable temporal and spatial variations. High values occurred in the coastal or shelf waters and low values in the offshore waters. The highest levels were observed in spring or summer and lowest in autumn. DMS or DMSPp distribution patterns were associated with water mass on a large geographical scale, while biological and chemical factors were more likely influential on smaller-scale variations. Diatoms could play an important role in total DMS or DMSPp abundance in coastal waters. Nitrate was found to have a two-phase relationship with DMSPp concentrations: positive when nitrate concentration was lower than 1 mumol/L, and negative when it was above. Anthropogenic factors such as sewage input and aquaculture also showed influences on DMS or DMSPp concentration.展开更多
The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecolog...The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecologically important species.Changes in salinity from 20-32 caused no measurable variation in cell growth or culture yield,but increased intracellular DMSP per cell by 30%.Nitrogen limitation caused up to a two-fold increase in total DMSP per cell and up to a three-fold increase in DMS per cell.These changes in DMSP and DMS per cell in the Skeletonema costatum cultures with nitrogen limitation and changing salinity were primarily attributed to the physiological functions of DMSP as an osmolyte and an antioxidant.The data obtained in this study indicated that nitrogen limitation and salinity may play an important role in climate feedback mechanisms involving biologically derived DMS.展开更多
The production of dimethylsulfide （DMS） and dimethylsulfoniopropionate （DMSP） by marine microalgae was investigated to elucidate more on the role of marine phytoplankton in ocean-atmosphere interactions in the glo...The production of dimethylsulfide （DMS） and dimethylsulfoniopropionate （DMSP） by marine microalgae was investigated to elucidate more on the role of marine phytoplankton in ocean-atmosphere interactions in the global biogeochemical sulfur cycle.Axenic laboratory cultures of four marine microalgae–Isochrysis galbana 8701,Pavlova viridis,Platymonas sp.and Chlorella were tested for DMSP production and conversion into DMS.Among these four microalgae,Isochrysis galbana 8701 and Pavlova viridis are two species of Haptophyta,while Chlorella and Platymonas sp.belong to Chlorophyta.The results demonstrate that the four algae can produce various amounts of DMS（P）,and their DMS（P） production was species specific.With similar cell size,more DMS was released by Haptophyta than that by Chlorophyta.DMS and dissolved DMSP （DMSPd） concentrations in algal cultures varied significantly during their life cycles.The highest release of DMS appeared in the senescent period for all the four algae.Variations in DMSP concentrations were in strong compliance with variations in algal cell densities during the growing period.A highly significant correlation was observed between the DMS and DMSPd concentrations in algal cultures,and there was a time lag for the variation trend of the DMS concentrations as compared with that of the DMSPd.The consistency of variation patterns of DMS and DMSPd implies that the DMSPd produced by phytoplankton cells has a marked effect on the production of DMS.In the present study,the authors’ results specify the significant contribution of the marine phytoplankton to DMS（P） production and the importance of biological control of DMS concentrations in oceanic water.展开更多
Temporal distributions of dimethylsulfide（DMS） and dimethylsulfoniopropionate（DMSP） were studied in the southern Yellow Sea（SYS） during April and September 2010. The mean concentrations（range） of DMS, dissolve...Temporal distributions of dimethylsulfide（DMS） and dimethylsulfoniopropionate（DMSP） were studied in the southern Yellow Sea（SYS） during April and September 2010. The mean concentrations（range） of DMS, dissolved and particulate DMSP（DMSPd and DMSPp） in the surface waters in spring are 1.69（0.48–4.92）, 3.18（0.68–6.75）and 15.81（2.82–52.33） nmol/L, respectively, and those in autumn are 2.80（1.33–5.10）, 5.45（2.19–11.30） and 30.63（6.24–137.87） nmol/L. On the whole, the distributions of DMS and DMSP in spring are completely different from those in autumn. In the central part of the SYS, the concentrations of DMS and DMSP in spring are obviously higher than those in autumn, but the opposite situation is found on the south of 34°N, which can be attributed to the differences in nutrients and phytoplankton biomass and composition between spring and autumn. Besides,the seasonal variations of water column stability and the Changjiang diluted water also have significant impact on the distributions of DMS and DMSP in spring and autumn on the south of 34°N. DMS and DMSPp concentrations coincide well with chlorophyll a（Chl a） levels in the spring cruise, suggesting that phytoplankton biomass may play an important role in controlling the distributions of DMS and DMSPp in the study area. Annual DMS emission rates range from 0.015 to 0.033 Tg/a（calculated by S）, respectively, using the equations of Liss and Merlivat（1986） and Wanninkhof（1992）. This result implies a significant relative contribution of the SYS to the global oceanic DMS fluxes.展开更多
The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water o...The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water of the Jiaozhou Bay, China and its adjacent area in May and August 2006. The concentrations of all these components showed a clear seasonal variation, with higher concen- trations occurring in summer. This can be mainly attributed to the higher phytoplankton biomass observed in summer. Simultaneously, the enrichment extents of DMSPd and DMSPp in the mi- crolayer also exhibited seasonal changes, with higher values in spring and lower ones in summer. Higher water temperature and stronger radiant intensity in summer can enhance their solubility and photochemical reaction in the microlayer water, reducing their enrichment factors （the ratio of concentration in the microlayer to that in the corresponding subsurface water）. A statistically significant relationship was found between the microlayer and subsurface water concentrations of DMS, DMSP and chlorophyll a, demonstrating that the biogenic materials in the microlayer come primarily from the underlying water. Moreover, our data show that the concentrations of DMSPp and DMS were significantly correlated with the levels of chlorophyll a, indicating that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. The ratios of DMS/chlorophyll a and DMSPpchlorophyll a varied little from spring to summer, suggesting that there was no obvious change in the proportion of DMSP producers in the phytoplankton community. The mean sea-to-air flux of DMS from the study area was estimated to be 5.70 μmol/（m^2·d）, which highlights the effects of human impacts on DMS emission.展开更多
A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. ...A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.展开更多
Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP...Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs.展开更多
The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges...The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges of DMS, dissolved DMSP （DMSPd）, and particulate DMSP （DMSPp） in surface waters were 6.85 （1.60-12.36）, 7.25 （2.28-19.05） and 61.87 （6.28-224.01） nmol/L, respectively. There were strong correlations between DMSPp and chlorophyll a in the Bohai Sea and the North Yellow Sea, respectively, and concentrations of DMS and DMSP were high, with a relatively high proportion of dinoflagellates, in the region of the South Yellow Sea Cold Water Mass. Results show that phytoplankton biomass and species composition were important factors that controlled the distribution of DMS and DMSP. Complex environmental factors, including nutrients, transparency, and terrestrial runoff, might also influence the variability in DMS and DMSP. Biological production and consumption rates of DMS in the Bohai Sea were higher than those in the Yellow Sea. DMS production rates were closely correlated with DMSPd concentrations. DMS and DMSP exhibited obvious diel variations, with high concentrations occurring in the late afternoon （16：00-19：00） and low concentrations occurring during the night, implying that the intensity of solar radiation had a significant influence on these variations. Size distributions of chlorophyll a and DMSPp were also investigated and large nanoplankton （5-20 μm）, mainly diatoms, contributed significantly to chlorophyll a and DMSPp at most stations. The average sea-to-air flux of DMS in the study area was estimated to be 11.07 μmol/（m^2·d） during the summer.展开更多
The Yellow Sea(YS)and East China Sea(ECS)are important marginal seas of the western Pacific.Understanding the dynamics of methane(CH_(4))in the YS and ECS are essential to evaluate the role of coastal seas in global w...The Yellow Sea(YS)and East China Sea(ECS)are important marginal seas of the western Pacific.Understanding the dynamics of methane(CH_(4))in the YS and ECS are essential to evaluate the role of coastal seas in global warming.We measured dissolved CH_(4) at various depths in the water column of the YS and ECS during a cruise from March to April 2017.The concentrations of CH_(4) varied greatly in different water masses,suggesting that the hydrographic conditions can substantially aff ect the CH_(4) distribution.The CH_(4) budget in the shelf of the ECS,which was estimated with a box model,suggests CH_(4) consumption in the water column was the major sink(>95%),followed by a loss with a total of 2.2%CH_(4) released to the atmosphere.Overall a local CH_(4) production of 0.28 nmol/(L·d)was needed to maintain the CH_(4) excess.Results from laboratory incubations showed an increase in CH_(4)(1.5 times higher than the value of the control)after the addition of dimethylsulfoniopropionate(DMSP).Field incubations result in a CH_(4) production rate of 1.2 nmol/(L·d)under a N-stressed conditions(N꞉P<1),indicates that the DMSP-dependent CH_(4) production prefer to occur in the oligotrophic seawaters,where nitrogen is depleted.This study demonstrates that the marginal seas of China is a hotspot for CH_(4) dynamics,and the cycling of methylated sulfur compounds(such as DMSP)may contribute importantly to locally formed CH_(4).This may have further implication to carbon and sulfur biogeochemical cycles in the western Pacific.展开更多
The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chl...The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chlorophyll a(Chl a)and their relationships with environmental variables and dimethylsulfide(DMS)and dimethylsulfoniopropionate(DMSP)were investigated in spring 2017(March 24 to April 16)in the East China Sea(26.0°-33.0°N,120.0°-128.0°E)and southern Yellow Sea(31.0°-36.0°N,120.0°-125.0°E).The spatial distributions of phytoplankton species composition and cell density were investigated by qualitative and quantitative methods and were compared with historical data to study phytoplankton species succession in the survey area.The results showed that there were 275 phytoplankton species belonging to 90 genera and 6 phyla in the survey area,of which 208 species belonged to 62 genera of Bacillariophyta and 56 species belonged to 20 genera of Pyrrophyta.The dominant phytoplankton species were Skeletonema dohrnii,Chaetoceros vanheurckii and Prorocentrum donghaiense.The phytoplankton cell densities ranged from 0.06×10^(4)cells/L to 418.73×10^(4)cells/L,with an average value of 21.46×10^(4)cells/L.In spring,the average ratio of Bacillariophyta/Pyrrophyta was41.13 for the entire study area.The areas with high phytoplankton cell density were mainly distributed in the northern South Yellow Sea and offshore waters of the East China Sea.According to a canonical correspondence analysis among phytoplankton and environmental parameters,the water Chl a concentrations were notably consistent with phytoplankton cell density(P<0.001),and both showed significant negative correlations with salinity and nitrite(P<0.05)and significant positive correlations with dissolved oxygen and pH(P<0.001).There was a significant positive correlation between diatom(both in cell density and in dominant species)and DMS(P<0.05),which indicated that diatoms play a greater role in DMS production in this investigated area.展开更多
The effects of selected environmental variables on the production of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) by laboratory batch cultures of microalgae were studied. The variations of DMS and DMSP ...The effects of selected environmental variables on the production of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) by laboratory batch cultures of microalgae were studied. The variations of DMS and DMSP output with algae growth and variations in nutrients and salinity are reported.展开更多
Dimethyl sulfide(DMS) is the most abundant form of volatile sulfur in Earth’s oceans, and is mainly produced by the enzymatic clevage of dimethylsulfoniopropionate(DMSP). DMS and DMSP play important roles in driving ...Dimethyl sulfide(DMS) is the most abundant form of volatile sulfur in Earth’s oceans, and is mainly produced by the enzymatic clevage of dimethylsulfoniopropionate(DMSP). DMS and DMSP play important roles in driving the global sulfur cycle and may affect climate. DMSP is proposed to serve as an osmolyte, a grazing deterrent, a signaling molecule, an antioxidant, a cryoprotectant and/or as a sink for excess sulfur. It was long believed that only marine eukaryotes such as phytoplankton produce DMSP. However, we recently discovered that marine heterotrophic bacteria can also produce DMSP, making them a potentially important source of DMSP. At present, one prokaryotic and two eukaryotic DMSP synthesis enzymes have been identified.Marine heterotrophic bacteria are likely the major degraders of DMSP, using two known pathways: demethylation and cleavage.Many phytoplankton and some fungi can also cleave DMSP. So far seven different prokaryotic and one eukaryotic DMSP lyases have been identified. This review describes the global distribution pattern of DMSP and DMS, the known genes for biosynthesis and cleavage of DMSP, and the physiological and ecological functions of these important organosulfur molecules, which will improve understanding of the mechanisms of DMSP and DMS production and their roles in the environment.展开更多
文摘Distribution of dimethylsulfide (DMS) and/or particulate dimethylsulfoniopropionate (DMSPp) concentrations in the Jiaozhou Bay, Zhifu Bay and East China Sea were investigated during the period of 1994 - 1998. Both DMS and DMSPp levels showed remarkable temporal and spatial variations. High values occurred in the coastal or shelf waters and low values in the offshore waters. The highest levels were observed in spring or summer and lowest in autumn. DMS or DMSPp distribution patterns were associated with water mass on a large geographical scale, while biological and chemical factors were more likely influential on smaller-scale variations. Diatoms could play an important role in total DMS or DMSPp abundance in coastal waters. Nitrate was found to have a two-phase relationship with DMSPp concentrations: positive when nitrate concentration was lower than 1 mumol/L, and negative when it was above. Anthropogenic factors such as sewage input and aquaculture also showed influences on DMS or DMSPp concentration.
基金Supported by the National Natural Science Foundation of China(Nos. 41030858 and 40525017)the Changjiang Scholars Program,Ministry of Education of China,the Science and Technology Key Project of Shandong Province (No. 2006GG2205024)the Taishan Scholars Program of Shandong Province
文摘The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecologically important species.Changes in salinity from 20-32 caused no measurable variation in cell growth or culture yield,but increased intracellular DMSP per cell by 30%.Nitrogen limitation caused up to a two-fold increase in total DMSP per cell and up to a three-fold increase in DMS per cell.These changes in DMSP and DMS per cell in the Skeletonema costatum cultures with nitrogen limitation and changing salinity were primarily attributed to the physiological functions of DMSP as an osmolyte and an antioxidant.The data obtained in this study indicated that nitrogen limitation and salinity may play an important role in climate feedback mechanisms involving biologically derived DMS.
基金The National Natural Science Foundation of China under contract Nos 40525017 and 40476034the Changjiang Scholars Programme,Ministry of Education of China+1 种基金the Science and Technology Key Project of Shandong Province under contract No.2006GG2205024the "Taishan Scholar" Special Research Fund of Shandong Province,China
文摘The production of dimethylsulfide （DMS） and dimethylsulfoniopropionate （DMSP） by marine microalgae was investigated to elucidate more on the role of marine phytoplankton in ocean-atmosphere interactions in the global biogeochemical sulfur cycle.Axenic laboratory cultures of four marine microalgae–Isochrysis galbana 8701,Pavlova viridis,Platymonas sp.and Chlorella were tested for DMSP production and conversion into DMS.Among these four microalgae,Isochrysis galbana 8701 and Pavlova viridis are two species of Haptophyta,while Chlorella and Platymonas sp.belong to Chlorophyta.The results demonstrate that the four algae can produce various amounts of DMS（P）,and their DMS（P） production was species specific.With similar cell size,more DMS was released by Haptophyta than that by Chlorophyta.DMS and dissolved DMSP （DMSPd） concentrations in algal cultures varied significantly during their life cycles.The highest release of DMS appeared in the senescent period for all the four algae.Variations in DMSP concentrations were in strong compliance with variations in algal cell densities during the growing period.A highly significant correlation was observed between the DMS and DMSPd concentrations in algal cultures,and there was a time lag for the variation trend of the DMS concentrations as compared with that of the DMSPd.The consistency of variation patterns of DMS and DMSPd implies that the DMSPd produced by phytoplankton cells has a marked effect on the production of DMS.In the present study,the authors’ results specify the significant contribution of the marine phytoplankton to DMS（P） production and the importance of biological control of DMS concentrations in oceanic water.
基金The National Natural Science Foundation of China under contract Nos 41320104008,41306069 and 41106071the Changjiang Scholars Programme,the Ministry of Education of China+1 种基金the Taishan Scholar Programme of Shandong Provincethe Fundamental Research Funds for the Central Universities
文摘Temporal distributions of dimethylsulfide（DMS） and dimethylsulfoniopropionate（DMSP） were studied in the southern Yellow Sea（SYS） during April and September 2010. The mean concentrations（range） of DMS, dissolved and particulate DMSP（DMSPd and DMSPp） in the surface waters in spring are 1.69（0.48–4.92）, 3.18（0.68–6.75）and 15.81（2.82–52.33） nmol/L, respectively, and those in autumn are 2.80（1.33–5.10）, 5.45（2.19–11.30） and 30.63（6.24–137.87） nmol/L. On the whole, the distributions of DMS and DMSP in spring are completely different from those in autumn. In the central part of the SYS, the concentrations of DMS and DMSP in spring are obviously higher than those in autumn, but the opposite situation is found on the south of 34°N, which can be attributed to the differences in nutrients and phytoplankton biomass and composition between spring and autumn. Besides,the seasonal variations of water column stability and the Changjiang diluted water also have significant impact on the distributions of DMS and DMSP in spring and autumn on the south of 34°N. DMS and DMSPp concentrations coincide well with chlorophyll a（Chl a） levels in the spring cruise, suggesting that phytoplankton biomass may play an important role in controlling the distributions of DMS and DMSPp in the study area. Annual DMS emission rates range from 0.015 to 0.033 Tg/a（calculated by S）, respectively, using the equations of Liss and Merlivat（1986） and Wanninkhof（1992）. This result implies a significant relative contribution of the SYS to the global oceanic DMS fluxes.
基金The National Natural Science Foundation of China under contract Nos 40476034, 40525017 and 40490265 the Science and Technology Key Project of Shandong Province, China under contract No 2006GG2205024the Taishan Mountain Scholar Construction Engineering Special Fund of Shandong Province, China
文摘The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water of the Jiaozhou Bay, China and its adjacent area in May and August 2006. The concentrations of all these components showed a clear seasonal variation, with higher concen- trations occurring in summer. This can be mainly attributed to the higher phytoplankton biomass observed in summer. Simultaneously, the enrichment extents of DMSPd and DMSPp in the mi- crolayer also exhibited seasonal changes, with higher values in spring and lower ones in summer. Higher water temperature and stronger radiant intensity in summer can enhance their solubility and photochemical reaction in the microlayer water, reducing their enrichment factors （the ratio of concentration in the microlayer to that in the corresponding subsurface water）. A statistically significant relationship was found between the microlayer and subsurface water concentrations of DMS, DMSP and chlorophyll a, demonstrating that the biogenic materials in the microlayer come primarily from the underlying water. Moreover, our data show that the concentrations of DMSPp and DMS were significantly correlated with the levels of chlorophyll a, indicating that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. The ratios of DMS/chlorophyll a and DMSPpchlorophyll a varied little from spring to summer, suggesting that there was no obvious change in the proportion of DMSP producers in the phytoplankton community. The mean sea-to-air flux of DMS from the study area was estimated to be 5.70 μmol/（m^2·d）, which highlights the effects of human impacts on DMS emission.
文摘A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.
基金Supported by the National Natural Science Foundation of China(Nos. 40525017 and 41030858)the Changjiang Scholars Program,Ministry of Education of China,and the National Basic Research Program of China (973 Program) (No. 2010CB428904)
文摘Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs.
基金Supported by the National Natural Science Foundation of China(Nos.41320104008,41030858,41306069)the National Natural Science Foundation for Creative Research Groups(No.41221004)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110132120010)the Cheung Kong Scholars Program of Chinathe Taishan Scholar Program of Shandong Provincethe Fundamental Research Funds for the Central Universities
文摘The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges of DMS, dissolved DMSP （DMSPd）, and particulate DMSP （DMSPp） in surface waters were 6.85 （1.60-12.36）, 7.25 （2.28-19.05） and 61.87 （6.28-224.01） nmol/L, respectively. There were strong correlations between DMSPp and chlorophyll a in the Bohai Sea and the North Yellow Sea, respectively, and concentrations of DMS and DMSP were high, with a relatively high proportion of dinoflagellates, in the region of the South Yellow Sea Cold Water Mass. Results show that phytoplankton biomass and species composition were important factors that controlled the distribution of DMS and DMSP. Complex environmental factors, including nutrients, transparency, and terrestrial runoff, might also influence the variability in DMS and DMSP. Biological production and consumption rates of DMS in the Bohai Sea were higher than those in the Yellow Sea. DMS production rates were closely correlated with DMSPd concentrations. DMS and DMSP exhibited obvious diel variations, with high concentrations occurring in the late afternoon （16：00-19：00） and low concentrations occurring during the night, implying that the intensity of solar radiation had a significant influence on these variations. Size distributions of chlorophyll a and DMSPp were also investigated and large nanoplankton （5-20 μm）, mainly diatoms, contributed significantly to chlorophyll a and DMSPp at most stations. The average sea-to-air flux of DMS in the study area was estimated to be 11.07 μmol/（m^2·d） during the summer.
基金Supported by the Ministry of Science and Technology of China(No.2016YFA0601302)the National Natural Science Foundation of China(Nos.41776122,42006040)+1 种基金the Taishan Scholars Program of Shandong Province(No.201511014)the Aoshan Talents Program of the Qingdao National Laboratory for Marine Science and Technology(No.2015ASTPOS08)。
文摘The Yellow Sea(YS)and East China Sea(ECS)are important marginal seas of the western Pacific.Understanding the dynamics of methane(CH_(4))in the YS and ECS are essential to evaluate the role of coastal seas in global warming.We measured dissolved CH_(4) at various depths in the water column of the YS and ECS during a cruise from March to April 2017.The concentrations of CH_(4) varied greatly in different water masses,suggesting that the hydrographic conditions can substantially aff ect the CH_(4) distribution.The CH_(4) budget in the shelf of the ECS,which was estimated with a box model,suggests CH_(4) consumption in the water column was the major sink(>95%),followed by a loss with a total of 2.2%CH_(4) released to the atmosphere.Overall a local CH_(4) production of 0.28 nmol/(L·d)was needed to maintain the CH_(4) excess.Results from laboratory incubations showed an increase in CH_(4)(1.5 times higher than the value of the control)after the addition of dimethylsulfoniopropionate(DMSP).Field incubations result in a CH_(4) production rate of 1.2 nmol/(L·d)under a N-stressed conditions(N꞉P<1),indicates that the DMSP-dependent CH_(4) production prefer to occur in the oligotrophic seawaters,where nitrogen is depleted.This study demonstrates that the marginal seas of China is a hotspot for CH_(4) dynamics,and the cycling of methylated sulfur compounds(such as DMSP)may contribute importantly to locally formed CH_(4).This may have further implication to carbon and sulfur biogeochemical cycles in the western Pacific.
基金The National Key Research and Development Program of China under contract Nos 2016YFA0601302 and 2018FY100202。
文摘The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chlorophyll a(Chl a)and their relationships with environmental variables and dimethylsulfide(DMS)and dimethylsulfoniopropionate(DMSP)were investigated in spring 2017(March 24 to April 16)in the East China Sea(26.0°-33.0°N,120.0°-128.0°E)and southern Yellow Sea(31.0°-36.0°N,120.0°-125.0°E).The spatial distributions of phytoplankton species composition and cell density were investigated by qualitative and quantitative methods and were compared with historical data to study phytoplankton species succession in the survey area.The results showed that there were 275 phytoplankton species belonging to 90 genera and 6 phyla in the survey area,of which 208 species belonged to 62 genera of Bacillariophyta and 56 species belonged to 20 genera of Pyrrophyta.The dominant phytoplankton species were Skeletonema dohrnii,Chaetoceros vanheurckii and Prorocentrum donghaiense.The phytoplankton cell densities ranged from 0.06×10^(4)cells/L to 418.73×10^(4)cells/L,with an average value of 21.46×10^(4)cells/L.In spring,the average ratio of Bacillariophyta/Pyrrophyta was41.13 for the entire study area.The areas with high phytoplankton cell density were mainly distributed in the northern South Yellow Sea and offshore waters of the East China Sea.According to a canonical correspondence analysis among phytoplankton and environmental parameters,the water Chl a concentrations were notably consistent with phytoplankton cell density(P<0.001),and both showed significant negative correlations with salinity and nitrite(P<0.05)and significant positive correlations with dissolved oxygen and pH(P<0.001).There was a significant positive correlation between diatom(both in cell density and in dominant species)and DMS(P<0.05),which indicated that diatoms play a greater role in DMS production in this investigated area.
文摘The effects of selected environmental variables on the production of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) by laboratory batch cultures of microalgae were studied. The variations of DMS and DMSP output with algae growth and variations in nutrients and salinity are reported.
基金supported by the National Natural Science Foundation of China (91751202 and 41730530)the National Key Research and Development Program of China (2016YFA0601303 and 2018YFC0310701)+1 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology (Qingdao) (2018SDKJ0406-4)Natural Environmental Research Council grants (NE/ N002385, NE/P012671 and NE/S001352) fund ARJC and JDT
文摘Dimethyl sulfide(DMS) is the most abundant form of volatile sulfur in Earth’s oceans, and is mainly produced by the enzymatic clevage of dimethylsulfoniopropionate(DMSP). DMS and DMSP play important roles in driving the global sulfur cycle and may affect climate. DMSP is proposed to serve as an osmolyte, a grazing deterrent, a signaling molecule, an antioxidant, a cryoprotectant and/or as a sink for excess sulfur. It was long believed that only marine eukaryotes such as phytoplankton produce DMSP. However, we recently discovered that marine heterotrophic bacteria can also produce DMSP, making them a potentially important source of DMSP. At present, one prokaryotic and two eukaryotic DMSP synthesis enzymes have been identified.Marine heterotrophic bacteria are likely the major degraders of DMSP, using two known pathways: demethylation and cleavage.Many phytoplankton and some fungi can also cleave DMSP. So far seven different prokaryotic and one eukaryotic DMSP lyases have been identified. This review describes the global distribution pattern of DMSP and DMS, the known genes for biosynthesis and cleavage of DMSP, and the physiological and ecological functions of these important organosulfur molecules, which will improve understanding of the mechanisms of DMSP and DMS production and their roles in the environment.
