2011 Vol. 30, No. 4
column
Display Method:
Examination of wind-wave interaction source term in WAVEWATCH III with tropical cyclone wind forcing
2011, (4): 1-13.
doi: 10.1007/s13131-011-0128-1
Abstract:
Results of drag coefficient (CD) from field observations and laboratory wave tank experiments indicate that the operational wave model can overestimate wind energy input under high wind conditions. The wind-wave interaction source term in WAVEWATCH Ⅲ has been modified to examine its behavior with tropical cyclone wind forcing. Using high resolution wind input, numerical experiments under idealized wind field and tropical cyclone Bonnie (1998) were designed to evaluate performance of the modified models. Both experiments indicate that the modified models with reduced CD significantly decrease wind energy input into the wave model and then simulate lower significant wave height (SWH) than the original model. However, the effects on spatial distribution of SWH, mean wavelength, mean wave direction, and directional wave spectra are insignificant. Due to the reduced wind energy input, the idealized experiment shows that the modified models simulate lower SWH than the original model in all four quadrants. The decrease in the front quadrants is significantly larger than that in the rear quadrants; it is larger under higher winds than lower winds. The realistic experiment on tropical cyclone Bonnie shows that the modified model with the various downward trends of CD in high winds creates a simulation that agrees best with scanning radar altimeter observations.
Results of drag coefficient (CD) from field observations and laboratory wave tank experiments indicate that the operational wave model can overestimate wind energy input under high wind conditions. The wind-wave interaction source term in WAVEWATCH Ⅲ has been modified to examine its behavior with tropical cyclone wind forcing. Using high resolution wind input, numerical experiments under idealized wind field and tropical cyclone Bonnie (1998) were designed to evaluate performance of the modified models. Both experiments indicate that the modified models with reduced CD significantly decrease wind energy input into the wave model and then simulate lower significant wave height (SWH) than the original model. However, the effects on spatial distribution of SWH, mean wavelength, mean wave direction, and directional wave spectra are insignificant. Due to the reduced wind energy input, the idealized experiment shows that the modified models simulate lower SWH than the original model in all four quadrants. The decrease in the front quadrants is significantly larger than that in the rear quadrants; it is larger under higher winds than lower winds. The realistic experiment on tropical cyclone Bonnie shows that the modified model with the various downward trends of CD in high winds creates a simulation that agrees best with scanning radar altimeter observations.
Multitime scale variations of sea surface temperature in the China seas based on the HadISST dataset
2011, (4): 14-23.
doi: 10.1007/s13131-011-0129-0
Abstract:
The variability of the sea surface temperature (SST) in the China seas has been studied in seasonal, interannual and interdecadal scales based on the monthly data of HadISST spanning from 1870 to 2007. The main results obtained are SST in the China offshore changes most actively at the seasonal scale with the intensity diminishing from north to south, as the temperature differences between summer and winter reaching 17 and 4℃ in the northern and southern areas, respectively. Moreover, seasonal variation near the coastal regions seems relatively stronger than that far from the coastline; significant interannual variations are detected, with the largest positive anomaly occurring in 1998 in the overall area. But as far as different domains are concerned, there exists great diversity, and the difference is also found between winter and summer. Differed from the seasonal variations, where the strongest interannual variability takes place, resides to the south of that of the seasonal ones in the northern section, nevertheless in the South China Sea, the most significant interannual variability is found in the deep basin; interdecadal changes of summer, winter and annual mean SST in different domains likewise present various features. In addition, a common dominant warming in recent 20 a are found in the overall China offshore with the strongest center located in the vicinity of the Changjiang Estuary in the East China Sea, which intensifies as high as 1.3℃ during the past 130 a.
The variability of the sea surface temperature (SST) in the China seas has been studied in seasonal, interannual and interdecadal scales based on the monthly data of HadISST spanning from 1870 to 2007. The main results obtained are SST in the China offshore changes most actively at the seasonal scale with the intensity diminishing from north to south, as the temperature differences between summer and winter reaching 17 and 4℃ in the northern and southern areas, respectively. Moreover, seasonal variation near the coastal regions seems relatively stronger than that far from the coastline; significant interannual variations are detected, with the largest positive anomaly occurring in 1998 in the overall area. But as far as different domains are concerned, there exists great diversity, and the difference is also found between winter and summer. Differed from the seasonal variations, where the strongest interannual variability takes place, resides to the south of that of the seasonal ones in the northern section, nevertheless in the South China Sea, the most significant interannual variability is found in the deep basin; interdecadal changes of summer, winter and annual mean SST in different domains likewise present various features. In addition, a common dominant warming in recent 20 a are found in the overall China offshore with the strongest center located in the vicinity of the Changjiang Estuary in the East China Sea, which intensifies as high as 1.3℃ during the past 130 a.
2011, (4): 24-32.
doi: 10.1007/s13131-011-0130-7
Abstract:
A typhoon leading is an important natural disaster to many disasters to China. A giant wave caused by it has brought large threat for an offshore project. Based on the maximum entropy principle, one new model which has 4 undetermined parameters is constructed, which is called the discrete maximum entropy probabilistic model. In practical applications, the design wave height is considered as soon as possible in a typhoon affected sea areas, the result fits the observed data well. Further more this model does not have the priority compared with other distributions as Poisson distribution. The model provides a theoretical basis for the engineering design more reasonable when considering typhoon factors comprehensively.
A typhoon leading is an important natural disaster to many disasters to China. A giant wave caused by it has brought large threat for an offshore project. Based on the maximum entropy principle, one new model which has 4 undetermined parameters is constructed, which is called the discrete maximum entropy probabilistic model. In practical applications, the design wave height is considered as soon as possible in a typhoon affected sea areas, the result fits the observed data well. Further more this model does not have the priority compared with other distributions as Poisson distribution. The model provides a theoretical basis for the engineering design more reasonable when considering typhoon factors comprehensively.
2011, (4): 33-42.
doi: 10.1007/s13131-011-0131-6
Abstract:
Using a suitable solvent for extracting pigments from sediment for high performance liquid chromatography (HPLC) analysis is critical for obtaining qualitative and quantitative estimates of phytoplanktonic and benthic algal biomass, as well as community composition. Five methodological factors (sample dehydration, extraction solvent, extraction duration, number of extractions, and ratio of solvent volume:sample weight) were studied using an L9 (34) orthogonal design in a sedimentary pigment extraction experiment on samples collected from the Changjiang large-river delta-front estuary (LDE), using HPLC analysis. The results show that the optimal extraction method for sedimentary pigments should include freeze-drying samples prior to extraction. The effects of different factors on sedimentary pigment extraction were separated by the L9 (34) orthogonal design experiments and showed that the extraction solvent was the most important, with extraction duration the second most important, and numbers of extraction and ratio of solvent volume:sample weight was the least important. The mixed solvent treatment comprised of acetone, methanol and water (80:15:5, by volume) was best for polar pigment extraction, with 100% acetone better for apolar pigments. For most pigments employed in this study (i.e., peridinin, fucoxanthin, alloxanthin, diatoxanthin, zeaxanthin, pheophytin-a and β-carotene), 3 h was found to be enough time for extraction from these deltaic sediments. However, for chlorophyll-a, the most important pigment used for estimating algal biomass, 12 h was needed. A small amount of solvent (3 ml) with duplicate extractions obtained the greatest amount and diversity of pigments. Unfortunately, no extraction method was found to be suitable for all pigments in sediments. The choice of extraction procedure should be made in accordance with the objective of each study, taking into consideration the properties of sediments and pigments in question.
Using a suitable solvent for extracting pigments from sediment for high performance liquid chromatography (HPLC) analysis is critical for obtaining qualitative and quantitative estimates of phytoplanktonic and benthic algal biomass, as well as community composition. Five methodological factors (sample dehydration, extraction solvent, extraction duration, number of extractions, and ratio of solvent volume:sample weight) were studied using an L9 (34) orthogonal design in a sedimentary pigment extraction experiment on samples collected from the Changjiang large-river delta-front estuary (LDE), using HPLC analysis. The results show that the optimal extraction method for sedimentary pigments should include freeze-drying samples prior to extraction. The effects of different factors on sedimentary pigment extraction were separated by the L9 (34) orthogonal design experiments and showed that the extraction solvent was the most important, with extraction duration the second most important, and numbers of extraction and ratio of solvent volume:sample weight was the least important. The mixed solvent treatment comprised of acetone, methanol and water (80:15:5, by volume) was best for polar pigment extraction, with 100% acetone better for apolar pigments. For most pigments employed in this study (i.e., peridinin, fucoxanthin, alloxanthin, diatoxanthin, zeaxanthin, pheophytin-a and β-carotene), 3 h was found to be enough time for extraction from these deltaic sediments. However, for chlorophyll-a, the most important pigment used for estimating algal biomass, 12 h was needed. A small amount of solvent (3 ml) with duplicate extractions obtained the greatest amount and diversity of pigments. Unfortunately, no extraction method was found to be suitable for all pigments in sediments. The choice of extraction procedure should be made in accordance with the objective of each study, taking into consideration the properties of sediments and pigments in question.
2011, (4): 43-52.
doi: 10.1007/s13131-011-0132-5
Abstract:
Paleoclimate record was revealed in Core MZ01 covering the mid-Holocene in age, located in the mud area of the inner continental shelf of the East China Sea. The ancient environment featured low-energy shallow sea shelf deposition formed mainly by coastal currents. The results show that temporal variation in geochemistry corresponds with the climate changes inferred from historical record. Relatively low MgO/Al2O3, CaO/K2O and high Al2O3/Na2O, K2O/Na2O, MnO/CaO values reflected a warm and humid climate in general, and vice versa. Therefore, these chemical indices could be applied to identify the variation of palaeoclimate in eastern China. The authors reconstructed the history of mid-Holocene climatic variation of the inner continental shelf of the East China Sea. From 8 300 a BP to 4 200 a BP, the climate was moderately warm and humid. From 4 200 a BP to 2 000 a BP, the climate turned cool and dry, and the regional climate frequently fluctuated in alternation of cool-dry periods (3 700 a BP, 2 850 a BP and 2 400 a BP) and warm-wet periods (3 250 a BP and 2 650 a BP). After 2 000 a BP, the climate of the study area gradually turned warm again, while the Little Ice Age, a cold event centered at around 250 a BP was indicated by those geochemical indices as mentioned above.
Paleoclimate record was revealed in Core MZ01 covering the mid-Holocene in age, located in the mud area of the inner continental shelf of the East China Sea. The ancient environment featured low-energy shallow sea shelf deposition formed mainly by coastal currents. The results show that temporal variation in geochemistry corresponds with the climate changes inferred from historical record. Relatively low MgO/Al2O3, CaO/K2O and high Al2O3/Na2O, K2O/Na2O, MnO/CaO values reflected a warm and humid climate in general, and vice versa. Therefore, these chemical indices could be applied to identify the variation of palaeoclimate in eastern China. The authors reconstructed the history of mid-Holocene climatic variation of the inner continental shelf of the East China Sea. From 8 300 a BP to 4 200 a BP, the climate was moderately warm and humid. From 4 200 a BP to 2 000 a BP, the climate turned cool and dry, and the regional climate frequently fluctuated in alternation of cool-dry periods (3 700 a BP, 2 850 a BP and 2 400 a BP) and warm-wet periods (3 250 a BP and 2 650 a BP). After 2 000 a BP, the climate of the study area gradually turned warm again, while the Little Ice Age, a cold event centered at around 250 a BP was indicated by those geochemical indices as mentioned above.
2011, (4): 53-59.
doi: 10.1007/s13131-011-0133-4
Abstract:
Color measuring is characterized by high resolution, high efficiency, and low cost. The application becomes increasingly common for tracing sediment sources and climate variation. Borehole LZ908 in the south coastal plain of the Laizhou Bay in northeast China, was used, of which the top 54 m containing all marine facies was focused, to test the feasibility of colorimetry as a climate indicator using visible light reflectance spectra and L*a*b* measurement results. The results show a good correction between lightness and calcium carbonate content in marine-terrigenous deposits; therefore, these deposits can be used as a proxy to study climate changes. Factor-analysis on the first derivative values of the raw visible light reflectance spectra produced three principal factors corresponding to goethite, organic matter, and hematite. Down hole variations in the three factor scores, lightness, calcium carbonate content, and grain size were quite consistent. Moreover, high lightness and low factor scores in goethite, hematite, and organics indicated glacial regression deposits, while low lightness and high factor scores in goethite, hematite, and organics indicated interglacial transgression deposits.
Color measuring is characterized by high resolution, high efficiency, and low cost. The application becomes increasingly common for tracing sediment sources and climate variation. Borehole LZ908 in the south coastal plain of the Laizhou Bay in northeast China, was used, of which the top 54 m containing all marine facies was focused, to test the feasibility of colorimetry as a climate indicator using visible light reflectance spectra and L*a*b* measurement results. The results show a good correction between lightness and calcium carbonate content in marine-terrigenous deposits; therefore, these deposits can be used as a proxy to study climate changes. Factor-analysis on the first derivative values of the raw visible light reflectance spectra produced three principal factors corresponding to goethite, organic matter, and hematite. Down hole variations in the three factor scores, lightness, calcium carbonate content, and grain size were quite consistent. Moreover, high lightness and low factor scores in goethite, hematite, and organics indicated glacial regression deposits, while low lightness and high factor scores in goethite, hematite, and organics indicated interglacial transgression deposits.
2011, (4): 60-74.
doi: 10.1007/s13131-011-0137-0
Abstract:
Chemometric approach based on principal component analysis (PCA) was utilized to examine the spatial variances of environmental and ecological characteristics in the Zhujiang River (Pearl River) Estuary and adjacent waters (ZREAW) in the South China Sea. The PCA result shows that the ZREAW can be divided into different zones according to the principal components and geographical locations of the study stations, and indicates that there are distinct regional variances on environmental features and the corresponding phytoplankton biomass and community structures among different areas. The spatial distribution of ecological features was implied to be influenced by various degrees of the different water resources, such as the Pearl River discharges, the coastal current and the oceanic water from the South China Sea. The variation of the biomass maximum zone and the complex impacts on the spatial distributions of phytoplankton biomass and production were also evaluated.
Chemometric approach based on principal component analysis (PCA) was utilized to examine the spatial variances of environmental and ecological characteristics in the Zhujiang River (Pearl River) Estuary and adjacent waters (ZREAW) in the South China Sea. The PCA result shows that the ZREAW can be divided into different zones according to the principal components and geographical locations of the study stations, and indicates that there are distinct regional variances on environmental features and the corresponding phytoplankton biomass and community structures among different areas. The spatial distribution of ecological features was implied to be influenced by various degrees of the different water resources, such as the Pearl River discharges, the coastal current and the oceanic water from the South China Sea. The variation of the biomass maximum zone and the complex impacts on the spatial distributions of phytoplankton biomass and production were also evaluated.
2011, (4): 75-88.
doi: 10.1007/s13131-011-0135-2
Abstract:
The Philippine Sea Plate has an extremely special tectonic background. As an oceanic plate, it is almost entirely surrounded by subduction zones with complex internal tectonic features. On the basis of enormous published literature, this paper offers a comprehensive overview of the tectonic and evolution history of the Philippine Basin and the Kyushu-Palau Ridge (KPR) in the Philippine Sea Plate, and discusses the geological features of KPR. Referring to relevant definitions of various "ridges" stipulated in United Nations Convention on the Law of the Sea, so the KPR is believed to be a remnant arc formed during the opening of the Parece Vela and Shikoku Basins in the Philippine Sea Plate. It is a submarine ridge on oceanic plate rather than a submarine elevation. And thus, it is not a natural component of the Japan continental margin.
The Philippine Sea Plate has an extremely special tectonic background. As an oceanic plate, it is almost entirely surrounded by subduction zones with complex internal tectonic features. On the basis of enormous published literature, this paper offers a comprehensive overview of the tectonic and evolution history of the Philippine Basin and the Kyushu-Palau Ridge (KPR) in the Philippine Sea Plate, and discusses the geological features of KPR. Referring to relevant definitions of various "ridges" stipulated in United Nations Convention on the Law of the Sea, so the KPR is believed to be a remnant arc formed during the opening of the Parece Vela and Shikoku Basins in the Philippine Sea Plate. It is a submarine ridge on oceanic plate rather than a submarine elevation. And thus, it is not a natural component of the Japan continental margin.
2011, (4): 89-95.
doi: 10.1007/s13131-011-0138-z
Abstract:
The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G2/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus's effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G2/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication.
The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G2/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus's effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G2/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication.
2011, (4): 96-101.
doi: 10.1007/s13131-011-0139-y
Abstract:
A marine riser transporting fluid in the Bohai Sea was selected as study object, using an experimental and numerical method to study its vortex induced vibration in waves. A similarity theory was used in the experiment to derive the experimental model from a practical model, the dynamic response of a riser model was measured in waves. A corresponding numerical simulation was performed using a finite element method. Comparisons were made with the results between the experiment and the numerical simulation. Some valuable results were obtained.
A marine riser transporting fluid in the Bohai Sea was selected as study object, using an experimental and numerical method to study its vortex induced vibration in waves. A similarity theory was used in the experiment to derive the experimental model from a practical model, the dynamic response of a riser model was measured in waves. A corresponding numerical simulation was performed using a finite element method. Comparisons were made with the results between the experiment and the numerical simulation. Some valuable results were obtained.
2011, (4): 102-106.
doi: 10.1007/s13131-011-0140-5
Abstract:
An attempt is made to infer the global mean sea level (GMSL) from a global tide gauge network and frame the problem in terms of the limitations of the network. The network, owing to its limited number of gauges and poor geographical distribution complicated further by unknown vertical land movements, is ill suited for measuring the GMSL. Yet it remains the only available source for deciphering the sea level rise over the last 100 a. The poor sampling characteristics of the tide gauge network have necessitated the usage of statistical inference. A linear optimal estimator based on the Gauss-Markov theorem seems well suited for the job. This still leaves a great deal of freedom in choosing the estimator. GMSL is poorly correlated with tide gauge measurements because the small uniform rise and fall of sea level are masked by the far larger regional signals. On the other hand, a regional mean sea level (RMSL) is much better correlated with the corresponding regional tide gauge measurements. Since the GMSL is simply the sum of RMSLs, the problem is transformed to one of estimating the RMSLs from regional tide gauge measurements. Specifically for the annual heating and cooling cycle, we separate the global ocean into 10°-latitude bands and compute for each 10°-latitude band the estimator that predicts its RMSL from tide gauges within. In the future, the statistical correlations are to be computed using satellite altimetry. However, as a first attempt, we have used numerical model outputs instead to isolate the problem so as not to get distracted by altimetry or tide gauge errors. That is, model outputs for sea level at tide gauge locations of the GLOSS network are taken as tide gauge measurements, and the RMSLs are computed from the model outputs. The results show an estimation error of approximately 2 mm versus an error of 2.7 cm if we simply average the tide gauge measurements to estimate the GMSL, caused by the much larger regional seasonal cycle and mesoscale variation plaguing the individual tide gauges. The numerical model, Los Alamos POP model Run 11 lasting 3 1/4 a, is one of the best eddy-resolving models and does a good job simulating the annual heating and cooling cycle, but it has no global or regional trend. Thus it has basically succeeded in estimating the seasonal cycle of the GMSL. This is still going to be the case even if we use the altimetry data because the RMSLs are dominated by the seasonal cycle in relatively short periods. For estimating the GMSL trend, longer records and low-pass filtering to isolate the statistical relations that are of interest. Here we have managed to avoid the much larger regional seasonal cycle plaguing individual tide gauges to get a fairly accurate estimate of the much smaller seasonal cycle in the GMSL so as to enhance the prospect of an accurate estimate of GMSL trend in short periods. One should reasonably expect to be able to do the same for longer periods during which tide gauges are plagued by much larger regional interannual (e. g., ENSO events) and decadal sea level variations. In the future, with the availability of the satellite altimeter data, we could use the same approach adopted here to estimate the seasonal variations of GMSL and RMSL accurately and remove these seasonal variations accordingly so as to get a more accurate statistical inference between the tide gauge data and the RMSLs (therefore the GMSL) at periods longer than 1 a, i. e., the long-term trend.
An attempt is made to infer the global mean sea level (GMSL) from a global tide gauge network and frame the problem in terms of the limitations of the network. The network, owing to its limited number of gauges and poor geographical distribution complicated further by unknown vertical land movements, is ill suited for measuring the GMSL. Yet it remains the only available source for deciphering the sea level rise over the last 100 a. The poor sampling characteristics of the tide gauge network have necessitated the usage of statistical inference. A linear optimal estimator based on the Gauss-Markov theorem seems well suited for the job. This still leaves a great deal of freedom in choosing the estimator. GMSL is poorly correlated with tide gauge measurements because the small uniform rise and fall of sea level are masked by the far larger regional signals. On the other hand, a regional mean sea level (RMSL) is much better correlated with the corresponding regional tide gauge measurements. Since the GMSL is simply the sum of RMSLs, the problem is transformed to one of estimating the RMSLs from regional tide gauge measurements. Specifically for the annual heating and cooling cycle, we separate the global ocean into 10°-latitude bands and compute for each 10°-latitude band the estimator that predicts its RMSL from tide gauges within. In the future, the statistical correlations are to be computed using satellite altimetry. However, as a first attempt, we have used numerical model outputs instead to isolate the problem so as not to get distracted by altimetry or tide gauge errors. That is, model outputs for sea level at tide gauge locations of the GLOSS network are taken as tide gauge measurements, and the RMSLs are computed from the model outputs. The results show an estimation error of approximately 2 mm versus an error of 2.7 cm if we simply average the tide gauge measurements to estimate the GMSL, caused by the much larger regional seasonal cycle and mesoscale variation plaguing the individual tide gauges. The numerical model, Los Alamos POP model Run 11 lasting 3 1/4 a, is one of the best eddy-resolving models and does a good job simulating the annual heating and cooling cycle, but it has no global or regional trend. Thus it has basically succeeded in estimating the seasonal cycle of the GMSL. This is still going to be the case even if we use the altimetry data because the RMSLs are dominated by the seasonal cycle in relatively short periods. For estimating the GMSL trend, longer records and low-pass filtering to isolate the statistical relations that are of interest. Here we have managed to avoid the much larger regional seasonal cycle plaguing individual tide gauges to get a fairly accurate estimate of the much smaller seasonal cycle in the GMSL so as to enhance the prospect of an accurate estimate of GMSL trend in short periods. One should reasonably expect to be able to do the same for longer periods during which tide gauges are plagued by much larger regional interannual (e. g., ENSO events) and decadal sea level variations. In the future, with the availability of the satellite altimeter data, we could use the same approach adopted here to estimate the seasonal variations of GMSL and RMSL accurately and remove these seasonal variations accordingly so as to get a more accurate statistical inference between the tide gauge data and the RMSLs (therefore the GMSL) at periods longer than 1 a, i. e., the long-term trend.
2011, (4): 107-121.
doi: 10.1007/s13131-011-0134-3
Abstract:
Based on the published data of structure geology, geochronology, petrology and isotope geochemistry, the authors of this paper have conducted studies on the tectonic evolution history of Japan arc system and Kyushu-Palau ridge (KPR). The studies show that the initial Japan arc system was resulted from the subduction of ancient Pacific plate beneath Eurasian Plate in Permian. It was part of an Andean-type continental volcanic arc which occurred in the offshore in the east of Asian during late Mesozoic era. The formation of tertiary back-arc basin (Japan Sea) resulted in the fundamental tectonic framework of the present arc system. Since Quaternary the system has been lying at E-W compression tectonic setting due to the eastward subduction of Amur Plate. It is expected that Japan arc system will be juxtaposed with Asian continent, which is similar to the present Taiwan arc system. The origin of Philippine Sea Plate (PSP) is still in debate. Some studies argued that it is a trapped oceanic crust segment, while the others insisted that it is a back-arc basin accompanied with ancient IBM arc. However, it is all agreed that the tectonic evolution of PSP started since 50 Ma, i.e., PSP has drifted from the site around equator at 50 Ma to the present site, and the subduction of PSP along Nankai trough-Ryukyu Trench beneath the Japan arc system during 6-2 Ma led to the formation of the present Ryukyu arc system. Of the PSP, the KPR has been found with the oldest rocks formed at 38 Ma. Combining with its geochemical characteristics of oceanic arc tholeiite, it is suggested that KPR is an intraoceanic volcanic arc, more specifically, a relic arc (i.e., rear arc of the ancient IBM) after rifting of ancient IBM. In addition, Amami-Daito province is of arc tectonic affinity, but has been affected by mantle plume. Therefore, based on their respective tectonic evolution history and geochemical characteristics of rock samples, it is inferred that there is no genetic relationship between Japan arc system and KPR. It is noted that rocks reflecting continental crust basement feature have been collected on the northern tip of KPR, which may be related to the process of KPR accreting on Japan arc, but the arc-continent accretion process are still at initial stage of modern continental crust accretion model. However, due to the scarcity of data of the northern tip of KPR, crustal structure of this location and its adjacent Nankai trough need to be further constrained by geophysical studies in the future.
Based on the published data of structure geology, geochronology, petrology and isotope geochemistry, the authors of this paper have conducted studies on the tectonic evolution history of Japan arc system and Kyushu-Palau ridge (KPR). The studies show that the initial Japan arc system was resulted from the subduction of ancient Pacific plate beneath Eurasian Plate in Permian. It was part of an Andean-type continental volcanic arc which occurred in the offshore in the east of Asian during late Mesozoic era. The formation of tertiary back-arc basin (Japan Sea) resulted in the fundamental tectonic framework of the present arc system. Since Quaternary the system has been lying at E-W compression tectonic setting due to the eastward subduction of Amur Plate. It is expected that Japan arc system will be juxtaposed with Asian continent, which is similar to the present Taiwan arc system. The origin of Philippine Sea Plate (PSP) is still in debate. Some studies argued that it is a trapped oceanic crust segment, while the others insisted that it is a back-arc basin accompanied with ancient IBM arc. However, it is all agreed that the tectonic evolution of PSP started since 50 Ma, i.e., PSP has drifted from the site around equator at 50 Ma to the present site, and the subduction of PSP along Nankai trough-Ryukyu Trench beneath the Japan arc system during 6-2 Ma led to the formation of the present Ryukyu arc system. Of the PSP, the KPR has been found with the oldest rocks formed at 38 Ma. Combining with its geochemical characteristics of oceanic arc tholeiite, it is suggested that KPR is an intraoceanic volcanic arc, more specifically, a relic arc (i.e., rear arc of the ancient IBM) after rifting of ancient IBM. In addition, Amami-Daito province is of arc tectonic affinity, but has been affected by mantle plume. Therefore, based on their respective tectonic evolution history and geochemical characteristics of rock samples, it is inferred that there is no genetic relationship between Japan arc system and KPR. It is noted that rocks reflecting continental crust basement feature have been collected on the northern tip of KPR, which may be related to the process of KPR accreting on Japan arc, but the arc-continent accretion process are still at initial stage of modern continental crust accretion model. However, due to the scarcity of data of the northern tip of KPR, crustal structure of this location and its adjacent Nankai trough need to be further constrained by geophysical studies in the future.
2011, (4): 122-128.
doi: 10.1007/s13131-011-0141-4
Abstract:
Studies were conducted to investigate the non-specific immune responses and disease-resistance of juvenile turbot Scophthalmus maximus, cultured at four different salinities (8, 20, 32 and 40). Three concentrations (3.75×107, 3.75×108 and 3.75×109 CFU/ml) of Vibrio anguillarum suspension were employed at each salinity to determine the 4-day LD50. The serum lysozyme activity, the alternative complement pathway activity (ACH50) and the phagocytosis percentage of head kidney in turbot were tested at 24, 48 and 72 h post-challenge of V. anguillarum (1.1×108 CFU/ml, 0.1 ml), respectively, to evaluate the non-specific immune responses at the selected rearing salinities. Fish reared at salinity 20 had the lowest mortality, namely, the highest 4-day LD50 value (8.88±0.17). Besides, the lysozyme activity, ACH50 and the phagocytosis of turbot were the highest at the salinity 20, but with the lowest at the salinity 40 treatment regardless of sampling time. In addition, the non-specific immune activities kept increasing within 72 h post-challenge of V. anguillarum, except that the lysozyme activity increased from 24 to 48 h, and then decreased from 48 to 72 h at 40 significantly. These results together indicate that rearing in intermediate salinity (20) was able to enhance the immunity and disease-resistance of turbot.
Studies were conducted to investigate the non-specific immune responses and disease-resistance of juvenile turbot Scophthalmus maximus, cultured at four different salinities (8, 20, 32 and 40). Three concentrations (3.75×107, 3.75×108 and 3.75×109 CFU/ml) of Vibrio anguillarum suspension were employed at each salinity to determine the 4-day LD50. The serum lysozyme activity, the alternative complement pathway activity (ACH50) and the phagocytosis percentage of head kidney in turbot were tested at 24, 48 and 72 h post-challenge of V. anguillarum (1.1×108 CFU/ml, 0.1 ml), respectively, to evaluate the non-specific immune responses at the selected rearing salinities. Fish reared at salinity 20 had the lowest mortality, namely, the highest 4-day LD50 value (8.88±0.17). Besides, the lysozyme activity, ACH50 and the phagocytosis of turbot were the highest at the salinity 20, but with the lowest at the salinity 40 treatment regardless of sampling time. In addition, the non-specific immune activities kept increasing within 72 h post-challenge of V. anguillarum, except that the lysozyme activity increased from 24 to 48 h, and then decreased from 48 to 72 h at 40 significantly. These results together indicate that rearing in intermediate salinity (20) was able to enhance the immunity and disease-resistance of turbot.
