2010 Vol. 29, No. 4
Display Method:
2010, (4): 1-2.
doi: 10.1007/s13131-010-0054-7
Abstract:
Drilling rig Deepwater Horizon in the Gulf of Mexico, leased by BP PLC from Transocean Ltd., exploded and caught on fire on April 20, 2010. The drilling location is at some 50 miles (80 kilometers) off the coast of Louisiana, USA.
Drilling rig Deepwater Horizon in the Gulf of Mexico, leased by BP PLC from Transocean Ltd., exploded and caught on fire on April 20, 2010. The drilling location is at some 50 miles (80 kilometers) off the coast of Louisiana, USA.
2010, (4): 3-12.
doi: 10.1007/s13131-010-0054-7
Abstract:
Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002, the study classifies the airflows in favor of sea fog over the Huanghai (Yellow) Sea in boreal spring (April-May) with the method of trajectory analysis, and analyzes the changes of proportions of warm and cold sea fogs along different paths of airflow. According to the heat balance equation, we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow paths. The major results are summarized as follows. (1) Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold fog. The proportion of warm fog only accounts for 44% in April, while increases as high as 57% in May. (2) Four primary airflow paths leading to spring sea fog are identified. They are originated from the northwest, east, southeast and southwest of the Huanghai Sea, respectively. The occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%, while these along the southwest and northwest airflow paths are merely 17.9% and 50%. (3) The key physical processes governing the warm/cold sea fog are heat advection transport, longwave radiation cooling at fog top, solar shortwave warming and latent heat flux between airsea interfaces. (4) The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection, and the vertical distribution of relative humidity.
Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002, the study classifies the airflows in favor of sea fog over the Huanghai (Yellow) Sea in boreal spring (April-May) with the method of trajectory analysis, and analyzes the changes of proportions of warm and cold sea fogs along different paths of airflow. According to the heat balance equation, we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow paths. The major results are summarized as follows. (1) Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold fog. The proportion of warm fog only accounts for 44% in April, while increases as high as 57% in May. (2) Four primary airflow paths leading to spring sea fog are identified. They are originated from the northwest, east, southeast and southwest of the Huanghai Sea, respectively. The occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%, while these along the southwest and northwest airflow paths are merely 17.9% and 50%. (3) The key physical processes governing the warm/cold sea fog are heat advection transport, longwave radiation cooling at fog top, solar shortwave warming and latent heat flux between airsea interfaces. (4) The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection, and the vertical distribution of relative humidity.
2010, (4): 13-20.
doi: 10.1007/s13131-010-0054-7
Abstract:
Some missions have been carried out to measure wave directional spectrum by synthetic aperture radar (SAR) and airborne real aperture radar (RAR) at a low incidence. Both them have their own advantages and limitations. Scientists hope that SAR and satellite-based RAR can complement each other for the research on wave properties in the future. For this study, the authors aim to simulate the satellite-based RAR system to validate performance for measuring the directional wave spectrum. The principal measurements are introduced and the simulation methods based on the one developed by Hauser are adopted and slightly modified. To enhance the authenticity of input spectrum and the wave spectrum measuring consistency for SAR and satellite-based RAR, the wave height spectrum inversed from Envisat ASAR data by cross spectrum technology is used as the input spectrum of the simulation system. In the process of simulation, the sea surface, backscattering signal, modulation spectrum and the estimated wave height spectrum are simulated in each look direction. Directional wave spectrum are measured based on the simulated observations from 0° to 360°. From the estimated wave spectrum, it has an 180° ambiguity like SAR, but it has no special high wave number cut off in all the direction. Finally, the estimated spectrum is compared with the input one in terms of the dominant wave wavelength, direction and SWH and the results are promising. The simulation shows that satellite-based RAR should be capable of measuring the directional wave properties. Moreover, it indicates satellite-based RAR basically can measure waves that SAR can measure.
Some missions have been carried out to measure wave directional spectrum by synthetic aperture radar (SAR) and airborne real aperture radar (RAR) at a low incidence. Both them have their own advantages and limitations. Scientists hope that SAR and satellite-based RAR can complement each other for the research on wave properties in the future. For this study, the authors aim to simulate the satellite-based RAR system to validate performance for measuring the directional wave spectrum. The principal measurements are introduced and the simulation methods based on the one developed by Hauser are adopted and slightly modified. To enhance the authenticity of input spectrum and the wave spectrum measuring consistency for SAR and satellite-based RAR, the wave height spectrum inversed from Envisat ASAR data by cross spectrum technology is used as the input spectrum of the simulation system. In the process of simulation, the sea surface, backscattering signal, modulation spectrum and the estimated wave height spectrum are simulated in each look direction. Directional wave spectrum are measured based on the simulated observations from 0° to 360°. From the estimated wave spectrum, it has an 180° ambiguity like SAR, but it has no special high wave number cut off in all the direction. Finally, the estimated spectrum is compared with the input one in terms of the dominant wave wavelength, direction and SWH and the results are promising. The simulation shows that satellite-based RAR should be capable of measuring the directional wave properties. Moreover, it indicates satellite-based RAR basically can measure waves that SAR can measure.
2010, (4): 21-27.
doi: 10.1007/s13131-010-0054-7
Abstract:
Waters along China coast are very turbid with high concentrations of suspended sediment nearly all the time, especially at the Hangzhou Bay, the Changjiang (Yangtze) River Estuary and the shoal along Jiangsu Province. In these turbid and optically complex waters, the standard MODIS ocean color products tend to have invalid values. Because the water-leaving radiances in the near-infrared (NIR) are significant resulting from the strong scattering of suspended particles, the standard MODIS atmospheric correction algorithm often gets no results or produces significant errors. And because of the complex water optical properties, the OC3 model used in the standard MODIS data processing tends to get extremely high chlorophyll-a (Chl-a) concentrations. In this paper, we present an atmospheric correction approach using MODIS short wave infrared (SWIR) bands based on the fact that water-leaving radiances are negligible in the SWIR region because of the extreme strong absorption of water even in turbid waters. A regional Chl-a concentration estimation model is also constructed for MODIS from in situ data. These algorithms are applied to MODIS Aqua data processing in the China coastal regions. In situ data collected in the Yellow Sea and the East China Sea in spring and autumn, 2003 are used to validate the performance. Reasonably good results have been obtained. It is noted that water-leaving reflectance in the NIR bands are significant in waters along the China coast with high sediment loadings. The satellite derived and in-situ reflectance spectra can match in the turbid waters along China coast, and there is relatively good linear relationship between satellite derived and in-situ reflectance. The RMSE value of Rrs(λ) is 0.0031 sr-1 for all the nine ocean color bands (412 to 869 nm). The satellite-derived Chl-a value is in the reasonable range and the root mean square percentage difference is 46.1%.
Waters along China coast are very turbid with high concentrations of suspended sediment nearly all the time, especially at the Hangzhou Bay, the Changjiang (Yangtze) River Estuary and the shoal along Jiangsu Province. In these turbid and optically complex waters, the standard MODIS ocean color products tend to have invalid values. Because the water-leaving radiances in the near-infrared (NIR) are significant resulting from the strong scattering of suspended particles, the standard MODIS atmospheric correction algorithm often gets no results or produces significant errors. And because of the complex water optical properties, the OC3 model used in the standard MODIS data processing tends to get extremely high chlorophyll-a (Chl-a) concentrations. In this paper, we present an atmospheric correction approach using MODIS short wave infrared (SWIR) bands based on the fact that water-leaving radiances are negligible in the SWIR region because of the extreme strong absorption of water even in turbid waters. A regional Chl-a concentration estimation model is also constructed for MODIS from in situ data. These algorithms are applied to MODIS Aqua data processing in the China coastal regions. In situ data collected in the Yellow Sea and the East China Sea in spring and autumn, 2003 are used to validate the performance. Reasonably good results have been obtained. It is noted that water-leaving reflectance in the NIR bands are significant in waters along the China coast with high sediment loadings. The satellite derived and in-situ reflectance spectra can match in the turbid waters along China coast, and there is relatively good linear relationship between satellite derived and in-situ reflectance. The RMSE value of Rrs(λ) is 0.0031 sr-1 for all the nine ocean color bands (412 to 869 nm). The satellite-derived Chl-a value is in the reasonable range and the root mean square percentage difference is 46.1%.
2010, (4): 28-37.
doi: 10.1007/s13131-010-0054-7
Abstract:
underwater topography is one of oceanic features detected by Synthetic Aperture Radar. Underwater topography SAR imaging mechanism shows that tidal current is the important factor for underwater topography SAR imaging. Thus under the same wind field condition, SAR images for the same area acquired at different time include different information of the underwater topography. To utilize synchronously SAR images acquired at different time for the underwater topography SAR detection and improve the precision of detection, based on the detection model of underwater topography with single SAR image and the periodicity of tidal current, a detection model of underwater topography with a series of SAR images acquired at different time is developed by combing with tide and tidal current numerical simulation. To testify the feasibility of the presented model, Taiwan Shoal located at the south outlet of Taiwan Strait is selected as study area and three SAR images are used in the underwater topography detection. The detection results are compared with the field observation data of water depth carried out by R/V Dongfanghong 2, and the errors of the detection are compared with those of the single SAR image. All comparisons show that the detection model presented in the paper improves the precision of underwater topography SAR detection, and the presented model is feasible.
underwater topography is one of oceanic features detected by Synthetic Aperture Radar. Underwater topography SAR imaging mechanism shows that tidal current is the important factor for underwater topography SAR imaging. Thus under the same wind field condition, SAR images for the same area acquired at different time include different information of the underwater topography. To utilize synchronously SAR images acquired at different time for the underwater topography SAR detection and improve the precision of detection, based on the detection model of underwater topography with single SAR image and the periodicity of tidal current, a detection model of underwater topography with a series of SAR images acquired at different time is developed by combing with tide and tidal current numerical simulation. To testify the feasibility of the presented model, Taiwan Shoal located at the south outlet of Taiwan Strait is selected as study area and three SAR images are used in the underwater topography detection. The detection results are compared with the field observation data of water depth carried out by R/V Dongfanghong 2, and the errors of the detection are compared with those of the single SAR image. All comparisons show that the detection model presented in the paper improves the precision of underwater topography SAR detection, and the presented model is feasible.
2010, (4): 38-47.
doi: 10.1007/s13131-010-0054-7
Abstract:
Three Landsat TM imageries (taken on 18 May 1987, 4 August 1998 and 28 July 2007) were used as the data source to identify the spatial and temporal variations of the suspended sediment concentration (SSC) in surface waters of the Changjiang Estuary. Atmospheric correction was carried out to determine the water-leaving reflectance using the FLAASH module. A regression equation between surveyed SSC and suspended sediment index was chosen to retrieve the SSC from the Landsat TM images. In addition, tidal harmonic analysis was performed to calculate tidal conditions corresponding to the acquisition time of satellite images. The results show that the SSC spatial patterns are similar to the in situ observation results, which show the highest SSC in the region of turbidity maximum zone in the Changjiang Estuary. For the period of 1987 to 2007, the SSC pattern is controlled mainly by tidal dynamic conditions and wind speeds, rather than sediment discharges from the river.
Three Landsat TM imageries (taken on 18 May 1987, 4 August 1998 and 28 July 2007) were used as the data source to identify the spatial and temporal variations of the suspended sediment concentration (SSC) in surface waters of the Changjiang Estuary. Atmospheric correction was carried out to determine the water-leaving reflectance using the FLAASH module. A regression equation between surveyed SSC and suspended sediment index was chosen to retrieve the SSC from the Landsat TM images. In addition, tidal harmonic analysis was performed to calculate tidal conditions corresponding to the acquisition time of satellite images. The results show that the SSC spatial patterns are similar to the in situ observation results, which show the highest SSC in the region of turbidity maximum zone in the Changjiang Estuary. For the period of 1987 to 2007, the SSC pattern is controlled mainly by tidal dynamic conditions and wind speeds, rather than sediment discharges from the river.
2010, (4): 48-61.
doi: 10.1007/s13131-010-0054-7
Abstract:
Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous, and lower in High Field Strength Elements (HFSE). These rocks are higher in Large Ion Lithophile Elements (LILE), thorium and uranium contents, positive lead anomalies, negative Nb-Ta anomalies, and enrichment in Light Rare Earth Elements (LREE). Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB), and rhyolites from the northern Okinawa Trough have the highest 207Pb/204Pb and 208Pb/204Pb ratios. The NECS shelf margin basalts have lower 87Sr/86Sr ratios, εNd and σ18O than the northern Okinawa Trough silicic rocks. According to 40K-40Ar isotopic ages of basalts from the NECS shelf margin, rifting of the Okinawa Trough may have been active since at least 3.65-3.86 Ma. The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere. The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough, and the formation of basaltic magmas closely relates to the thinning of continental crust. The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough, which could have been generated by the interaction of basaltic melt with an enriched crustal component. From the Ryukyu island arc to East China, the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE), suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate, and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.
Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous, and lower in High Field Strength Elements (HFSE). These rocks are higher in Large Ion Lithophile Elements (LILE), thorium and uranium contents, positive lead anomalies, negative Nb-Ta anomalies, and enrichment in Light Rare Earth Elements (LREE). Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB), and rhyolites from the northern Okinawa Trough have the highest 207Pb/204Pb and 208Pb/204Pb ratios. The NECS shelf margin basalts have lower 87Sr/86Sr ratios, εNd and σ18O than the northern Okinawa Trough silicic rocks. According to 40K-40Ar isotopic ages of basalts from the NECS shelf margin, rifting of the Okinawa Trough may have been active since at least 3.65-3.86 Ma. The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere. The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough, and the formation of basaltic magmas closely relates to the thinning of continental crust. The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough, which could have been generated by the interaction of basaltic melt with an enriched crustal component. From the Ryukyu island arc to East China, the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE), suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate, and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.
2010, (4): 62-77.
doi: 10.1007/s13131-010-0054-7
Abstract:
Locating the quantitized natural sediment fingerprints is an important work for marine sediment dynamics study. The total of 146 sediment samples were collected from the Shelf of the East China Sea and five rivers, including Huanghe (Yellow), Changjiang (Yangtze), Qiantang, Ou and Min River. The sediment grain size and the contents of rare earth elements (REEs) were measured with laser particle size analyzer and ICP-MS technology. The results show that absolute REE content (ΣREE) and the concentration ratio of light REEs to heavy REEs (L/HREE) are different in the sediments among those rivers. There are higher REE contents in being less than 2 m and 2-31 μm fractions in the Changjiang Estuary surface sediments. The REE contents of bulk sediment are dominated by the corresponding values of those leading size-fractions. REE of sediment is higher close to the estuaries and declines seaward on the inner shelf of the East China Sea (ECS). The L/HREE ratio has a tendency of increase southward from 28°N. Hydrodynamic conditions plays a predominate role on spacial distributions of the surficial sediment's REE parameters. In some situations, the currents tend to remove the coarser light grains from initial populations, as well as the deposit of the finer heavy mineral grains. In other situations, the currents will change the ratio of sediment constituents, such as ratio between silts and clays in the sediments. As a result, the various values of REE or L/HREE ratio in different bulk sediments are more affected by the change of size-fractions than source location. Under the long-term stable hydrodynamic environment, i.e., the East China Sea Shelf, new sediment transport model based on the size and density gradation concept may help to understand the spatial distribution patterns of REE parameters.
Locating the quantitized natural sediment fingerprints is an important work for marine sediment dynamics study. The total of 146 sediment samples were collected from the Shelf of the East China Sea and five rivers, including Huanghe (Yellow), Changjiang (Yangtze), Qiantang, Ou and Min River. The sediment grain size and the contents of rare earth elements (REEs) were measured with laser particle size analyzer and ICP-MS technology. The results show that absolute REE content (ΣREE) and the concentration ratio of light REEs to heavy REEs (L/HREE) are different in the sediments among those rivers. There are higher REE contents in being less than 2 m and 2-31 μm fractions in the Changjiang Estuary surface sediments. The REE contents of bulk sediment are dominated by the corresponding values of those leading size-fractions. REE of sediment is higher close to the estuaries and declines seaward on the inner shelf of the East China Sea (ECS). The L/HREE ratio has a tendency of increase southward from 28°N. Hydrodynamic conditions plays a predominate role on spacial distributions of the surficial sediment's REE parameters. In some situations, the currents tend to remove the coarser light grains from initial populations, as well as the deposit of the finer heavy mineral grains. In other situations, the currents will change the ratio of sediment constituents, such as ratio between silts and clays in the sediments. As a result, the various values of REE or L/HREE ratio in different bulk sediments are more affected by the change of size-fractions than source location. Under the long-term stable hydrodynamic environment, i.e., the East China Sea Shelf, new sediment transport model based on the size and density gradation concept may help to understand the spatial distribution patterns of REE parameters.
2010, (4): 78-87.
doi: 10.1007/s13131-010-0054-7
Abstract:
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.
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.
2010, (4): 88-97.
doi: 10.1007/s13131-010-0054-7
Abstract:
The community composition, abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South China Sea were investigated by morphological method, bacterial cultivation and biochemical methods over an annual cycle. Aeromonas and Pseudomonas were the predominant genera among the Gram-negative bacteria. The bacterioplankton abundance fluctuated from 2.07×108 to 2.44×109 cells/dm3, and culturable bacteria abundance ranged between 0.1×106 and 16.07×106 CFU/dm3. The Culturablity of heterotrophic bacteria ranged between 0.01% and 1.31%. The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng Bay. Throughout the bay, a significantly positive relationship was evidenced between bacterial culturability and temperature, meanswhile bacterial culturability was significantly inversely related with salinity. The positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water. A positive relationship was found between culturability and DIN all the bay, but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.
The community composition, abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South China Sea were investigated by morphological method, bacterial cultivation and biochemical methods over an annual cycle. Aeromonas and Pseudomonas were the predominant genera among the Gram-negative bacteria. The bacterioplankton abundance fluctuated from 2.07×108 to 2.44×109 cells/dm3, and culturable bacteria abundance ranged between 0.1×106 and 16.07×106 CFU/dm3. The Culturablity of heterotrophic bacteria ranged between 0.01% and 1.31%. The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng Bay. Throughout the bay, a significantly positive relationship was evidenced between bacterial culturability and temperature, meanswhile bacterial culturability was significantly inversely related with salinity. The positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water. A positive relationship was found between culturability and DIN all the bay, but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.
2010, (4): 98-105.
doi: 10.1007/s13131-010-0054-7
Abstract:
16S rDNA sequencing results from this study and literatures demonstrate that sediment bacteria in the South China Sea (SCS) were very diverse, which contained 22 of the 24 phyla of bacteria investigated from marine sediment, however, it was very imbalance among stations. So bacterial diversity from 15 samples which covered a wide range of sediment types from 20 to 3 888 m in depth was studied in DGGE (denature gradient gel electrophoresis) in this paper. The DGGE results indicate that both sediment bacterial diversity and diversity difference among stations were significant. Thirty representative and differential fingerprints among samples were recovered and sequenced, phylogenetic analysis indicates that they may belong to Proteobacteria (α-, β-, γ-, δ-, ε-), Planctomycetes, Firmicutes, Chloroflexi, Acidobacteria, Actinobacteria, Nitrospirae, Gemmatimonadetes, candidate division WS3 and so on, of which, Gemmatimonadetes and candidate division WS3 bacteria were first detected in SCS sediment. This study also shows that bacterial diversity analysis based on DGGE was more potential than traditional 16S rDNA clone library in multiple sample analysis.
16S rDNA sequencing results from this study and literatures demonstrate that sediment bacteria in the South China Sea (SCS) were very diverse, which contained 22 of the 24 phyla of bacteria investigated from marine sediment, however, it was very imbalance among stations. So bacterial diversity from 15 samples which covered a wide range of sediment types from 20 to 3 888 m in depth was studied in DGGE (denature gradient gel electrophoresis) in this paper. The DGGE results indicate that both sediment bacterial diversity and diversity difference among stations were significant. Thirty representative and differential fingerprints among samples were recovered and sequenced, phylogenetic analysis indicates that they may belong to Proteobacteria (α-, β-, γ-, δ-, ε-), Planctomycetes, Firmicutes, Chloroflexi, Acidobacteria, Actinobacteria, Nitrospirae, Gemmatimonadetes, candidate division WS3 and so on, of which, Gemmatimonadetes and candidate division WS3 bacteria were first detected in SCS sediment. This study also shows that bacterial diversity analysis based on DGGE was more potential than traditional 16S rDNA clone library in multiple sample analysis.
2010, (4): 106-115.
doi: 10.1007/s13131-010-0054-7
Abstract:
The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao, Shandong Province, China, during a six-month study period (a complete shrimp-culture cycle) from May to October 2002. The results reveal that:(1) the protist communities represented five trophic and functional groups of the species identified, about 60% were photoautotrophs, 20% algivores, 12% bacterivores, 5% raptors and about 3% non-selectives; (2) the photoautotrophs, algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales, the succession of dominance typically being bacterivores→photoautotrophs→algivores, with the raptors dominating the protist communities in a single sample (early June); (3) the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs, bacterivores, raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively; (4) five functional groups of protist communities represented significant correlations with water nutrients (i.e., NH3-N, NO3-N, and PO4), either alone or in combination with temperature, of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a, while bacterivores were strongly related to nitrogen and the concentration of bacteria. These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.
The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao, Shandong Province, China, during a six-month study period (a complete shrimp-culture cycle) from May to October 2002. The results reveal that:(1) the protist communities represented five trophic and functional groups of the species identified, about 60% were photoautotrophs, 20% algivores, 12% bacterivores, 5% raptors and about 3% non-selectives; (2) the photoautotrophs, algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales, the succession of dominance typically being bacterivores→photoautotrophs→algivores, with the raptors dominating the protist communities in a single sample (early June); (3) the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs, bacterivores, raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively; (4) five functional groups of protist communities represented significant correlations with water nutrients (i.e., NH3-N, NO3-N, and PO4), either alone or in combination with temperature, of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a, while bacterivores were strongly related to nitrogen and the concentration of bacteria. These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.
2010, (4): 116-128.
doi: 10.1007/s13131-010-0054-7
Abstract:
The excitation spectra of chlorophyll (Chl) fluorescence can be used to differentiate phytoplankton populations at phylum level in vivo and in situ within a few minutes. The investigated phytoplankton divisions (Dinophyta, Bacillariophyta, Chrysophyta, Cyanophyta, Cryptophyta, Chlorophyta) are each characterized by a specific composition of photosynthetic antenna pigments and, consequently, by a specific excitation spectrum of the Chl fluorescence. Norm excitation spectra (emission of 680 nm and excitation of 400-600 nm) of every division were obtained from several species per division by a F4500 fluorescence spectrophotometer. Fisher's linear discriminant analysis of the norm spectra shows that the divisions could be discriminated. The discrimination method, established by multivariate linear regression and weighted least squares, was used to differentiate the phytoplankton samples cultured in the laboratory and samples collected from the Jiaozhao Bay at division level. The correctly discriminated samples were more than 94% for single algal species ones, more than 84% for simulatively mixed ones, more than 83% for real mixed ones and 100% for samples collected from the Jiaozhou Bay for the dominant species. The method for phytoplankton differentiation described here can be applied to routine checking by fluorescence spectrophotometer, and benefit the monitoring and supervision tasks related to phytoplankton populations in the marine environments.
The excitation spectra of chlorophyll (Chl) fluorescence can be used to differentiate phytoplankton populations at phylum level in vivo and in situ within a few minutes. The investigated phytoplankton divisions (Dinophyta, Bacillariophyta, Chrysophyta, Cyanophyta, Cryptophyta, Chlorophyta) are each characterized by a specific composition of photosynthetic antenna pigments and, consequently, by a specific excitation spectrum of the Chl fluorescence. Norm excitation spectra (emission of 680 nm and excitation of 400-600 nm) of every division were obtained from several species per division by a F4500 fluorescence spectrophotometer. Fisher's linear discriminant analysis of the norm spectra shows that the divisions could be discriminated. The discrimination method, established by multivariate linear regression and weighted least squares, was used to differentiate the phytoplankton samples cultured in the laboratory and samples collected from the Jiaozhao Bay at division level. The correctly discriminated samples were more than 94% for single algal species ones, more than 84% for simulatively mixed ones, more than 83% for real mixed ones and 100% for samples collected from the Jiaozhou Bay for the dominant species. The method for phytoplankton differentiation described here can be applied to routine checking by fluorescence spectrophotometer, and benefit the monitoring and supervision tasks related to phytoplankton populations in the marine environments.
