Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea （AOA） and betaproteobacteria （13-AOB） in surface sediments from ...Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea （AOA） and betaproteobacteria （13-AOB） in surface sediments from the East China Sea （ECS） were investigated using ammonia monooxygenase ct subunit （amoA） gene. In order to characterize the community of AOA and 13-AOB, real-time quantitative polymerase chain reaction （qPCR） was carried out in this study, along with environmental parameters. The abundance of 13-AOB amoA gene （2.17x 10^6-4.54x10^7 copy numbers per gram wet weight sediment） was always greater than that ofAOA amoA gene （2.18x 105-9.89x 10^6 copy numbers per gram wet weight sediment） in all sampling stations. The qPCR results were correlated with environmental parameters. AOA amoA gene copy numbers in April were positively related to temperature and nitrite concentration （p〈0.05）. 13-AOB amoA gene copy numbers in August correlated negatively with salinity （p〈0.01）, and correlated positively with ammonium concentration （p〈0.05）. With the increase of salinity, the amoA gene copy ratio of AOB to AOA had a tendency to decrease, which suggested 13-AOB dominated in the area of high level ammonium and AOA preferred high salinity area.展开更多
Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at var...Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.展开更多
A great deal of oil contaminated the shoreline by the Qingdao oil pipeline explosion in 2013. The four oildegrading consortia were enriched from sediment samples with crude oil as sole carbon and energy sources. The b...A great deal of oil contaminated the shoreline by the Qingdao oil pipeline explosion in 2013. The four oildegrading consortia were enriched from sediment samples with crude oil as sole carbon and energy sources. The biodiversity and community analysis showed that the Luteibacter, Parvibaculum and a genus belonging to Alcanivoracaceae were found predominant bacteria in the four consortia, which belonged to Proteobacteria. Nine strains exhibiting distinct 16S rRNA gene sequences were isolated from the consortia. These strains were identified to eight genera based on 16S rRNA gene sequences. Five of the nine strains degraded more than 30% of the crude oil in two weeks by gravimetric method. From the analysis of GC-MS, most of the isolated strains tended to degrade n-alkanes rather than PAHs. Five strains showed high degrading ability of the total n-alkanes. Only Strain D2 showed great PAHs degrading ability and the degrading rates ranged from 34.9% to 77.5%. The sequencing analysis of the oil-degrading consortia confirmed that the genus of Alcanivorax was one of the dominant bacteria in Consortia A and E and Strain E4 might be one of the dominant bacteria. The strains obtained in this study demonstrated the potential for oil bioremediation in oil-contaminated beach ecosystems.展开更多
Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfat...Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfate reduction pathway,has been found in all known SRB that have been tested so far.In this study,the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification,cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene(dsr B).Based on dsr B clone libraries constructed in this study,diversified SRB were found,represented by 173 unique OTUs.Certain cloned sequences were associated with Desulfobacteraceae,Desulfobulbaceae,and a large fraction(60%) of novel sequences that have deeply branched groups in the dsr B tree,indicating that novel SRB inhabit the surface sediments.In addition,correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis(RDA).The result revealed that temperature,salinity and the content of TOC were most closely correlated with the SRB communities.More information on SRB community was obtained by applying the utility of Uni Frac to published dsr B gene sequences from this study and other 9 different kinds of marine environments.The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments,and that geographic positions and environmental factors influenced the SRB community distribution.展开更多
Nitrogen(N), Phosphorus(P), and Iron(Fe) are essential elements for cellular structure and metabolism. In addition to dissolved inorganic nitrogen(DIN), phytoplankton is able to utilize dissolved organic nitrogen(DON)...Nitrogen(N), Phosphorus(P), and Iron(Fe) are essential elements for cellular structure and metabolism. In addition to dissolved inorganic nitrogen(DIN), phytoplankton is able to utilize dissolved organic nitrogen(DON). There is general consensus that both bacteria and higher plants nitrogen metabolism is affected by phosphate availability; this was also found to be true in coccolithophorid. Iron affects the structure and function of ecosystems through its effects on nitrogen metabolism. However, it is unclear how these nutrients affect Skeletonema marinoi's nitrogen metabolism. Here, using RT-qPCR, we investigate effects of N, P, and Fe on S. marinoi's nitrogen metabolism and nitrate reductase activity. These results illuminate that in S. marinoi, various nutrients have direct regulation on these genes expression at the molecular level. The varying degree of responses for these genes expression with differing N sources may act to increase the efficiency of nutrient capture when nitrate is limited. Suitable gene expression occurs at a N/P ratio of 16, which represents the atomic N/P ratio of phytoplankton cells and N/P concentrations in ocean; thus, nitrogen metabolism gene expression should be regulated by the existing N/P ratios in the phytoplankton's internal and external environment. Fe concentration has a direct and significant effect on nitrogen metabolism by regulating gene expression and nitrate reductase activity. Gene expression profiles identified in S. marinoi provide a foundation for understanding molecular mechanisms behind diatom nitrogen metabolism with changing N, P, and Fe nutrients allowing a basic understanding of how diatom growth is affected by nutrient utilization.展开更多
This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction...This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.展开更多
基金The National Natural Science Foundation of China under contract No.40920164004the National Basic Research Program (973 Program) of China under contract No.2011CB403602the Foundation for Innovative Research Groups of the National Natural Science Foundation of China under contract No.41221004
文摘Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea （AOA） and betaproteobacteria （13-AOB） in surface sediments from the East China Sea （ECS） were investigated using ammonia monooxygenase ct subunit （amoA） gene. In order to characterize the community of AOA and 13-AOB, real-time quantitative polymerase chain reaction （qPCR） was carried out in this study, along with environmental parameters. The abundance of 13-AOB amoA gene （2.17x 10^6-4.54x10^7 copy numbers per gram wet weight sediment） was always greater than that ofAOA amoA gene （2.18x 105-9.89x 10^6 copy numbers per gram wet weight sediment） in all sampling stations. The qPCR results were correlated with environmental parameters. AOA amoA gene copy numbers in April were positively related to temperature and nitrite concentration （p〈0.05）. 13-AOB amoA gene copy numbers in August correlated negatively with salinity （p〈0.01）, and correlated positively with ammonium concentration （p〈0.05）. With the increase of salinity, the amoA gene copy ratio of AOB to AOA had a tendency to decrease, which suggested 13-AOB dominated in the area of high level ammonium and AOA preferred high salinity area.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404402)the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02)the Basic Scientific Foundation of Guangxi Institute of Public Welfare Scientific Research(No.2019GMRC03)
文摘Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.
基金The National Natural Science Foundation of China under contract Nos 41406127 and 41476103the Basic Scientific Fund for National Public Research Institutes of China under contract No.2015T05+2 种基金the National Natural Science Foundation of ChinaShandong Joint Funded Project under contract No.U1406403the Marine Science and Technology Project of Huangdao District under contract No.2014-4-20the 2012 Taishan Scholar Award and China-ASEAN Maritime Cooperation Fund East Asia Marine Cooperation Platform
文摘A great deal of oil contaminated the shoreline by the Qingdao oil pipeline explosion in 2013. The four oildegrading consortia were enriched from sediment samples with crude oil as sole carbon and energy sources. The biodiversity and community analysis showed that the Luteibacter, Parvibaculum and a genus belonging to Alcanivoracaceae were found predominant bacteria in the four consortia, which belonged to Proteobacteria. Nine strains exhibiting distinct 16S rRNA gene sequences were isolated from the consortia. These strains were identified to eight genera based on 16S rRNA gene sequences. Five of the nine strains degraded more than 30% of the crude oil in two weeks by gravimetric method. From the analysis of GC-MS, most of the isolated strains tended to degrade n-alkanes rather than PAHs. Five strains showed high degrading ability of the total n-alkanes. Only Strain D2 showed great PAHs degrading ability and the degrading rates ranged from 34.9% to 77.5%. The sequencing analysis of the oil-degrading consortia confirmed that the genus of Alcanivorax was one of the dominant bacteria in Consortia A and E and Strain E4 might be one of the dominant bacteria. The strains obtained in this study demonstrated the potential for oil bioremediation in oil-contaminated beach ecosystems.
基金supported by the National Natural Science Foundation of China and the National Basic Research Program of China (973 program)(Nos.40920164004,2011CB403602,41375143)
文摘Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfate reduction pathway,has been found in all known SRB that have been tested so far.In this study,the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification,cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene(dsr B).Based on dsr B clone libraries constructed in this study,diversified SRB were found,represented by 173 unique OTUs.Certain cloned sequences were associated with Desulfobacteraceae,Desulfobulbaceae,and a large fraction(60%) of novel sequences that have deeply branched groups in the dsr B tree,indicating that novel SRB inhabit the surface sediments.In addition,correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis(RDA).The result revealed that temperature,salinity and the content of TOC were most closely correlated with the SRB communities.More information on SRB community was obtained by applying the utility of Uni Frac to published dsr B gene sequences from this study and other 9 different kinds of marine environments.The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments,and that geographic positions and environmental factors influenced the SRB community distribution.
基金supported by the National Natural Science Foundation of China (No. 41521064)the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology (No. 2016ASKJ02)the Public Science and Technology Research Funds Projects of Ocean (No. 201205031)
文摘Nitrogen(N), Phosphorus(P), and Iron(Fe) are essential elements for cellular structure and metabolism. In addition to dissolved inorganic nitrogen(DIN), phytoplankton is able to utilize dissolved organic nitrogen(DON). There is general consensus that both bacteria and higher plants nitrogen metabolism is affected by phosphate availability; this was also found to be true in coccolithophorid. Iron affects the structure and function of ecosystems through its effects on nitrogen metabolism. However, it is unclear how these nutrients affect Skeletonema marinoi's nitrogen metabolism. Here, using RT-qPCR, we investigate effects of N, P, and Fe on S. marinoi's nitrogen metabolism and nitrate reductase activity. These results illuminate that in S. marinoi, various nutrients have direct regulation on these genes expression at the molecular level. The varying degree of responses for these genes expression with differing N sources may act to increase the efficiency of nutrient capture when nitrate is limited. Suitable gene expression occurs at a N/P ratio of 16, which represents the atomic N/P ratio of phytoplankton cells and N/P concentrations in ocean; thus, nitrogen metabolism gene expression should be regulated by the existing N/P ratios in the phytoplankton's internal and external environment. Fe concentration has a direct and significant effect on nitrogen metabolism by regulating gene expression and nitrate reductase activity. Gene expression profiles identified in S. marinoi provide a foundation for understanding molecular mechanisms behind diatom nitrogen metabolism with changing N, P, and Fe nutrients allowing a basic understanding of how diatom growth is affected by nutrient utilization.
基金supported by the National Natural Science Foundation of China (NSFC project 20775074)
文摘This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.
