2019 Vol. 41, No. 2
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2019, 41(2): .
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2019, 41(2): 1-13.
doi: 10.3969/j.issn.0253-4193.2019.02.001
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Based on linear shallow water equation and tsunami amplitude Green's law, a rapid earthquake induced tsunami amplitude forecast system covering the Pacific Ocean is developed. Thirty-two hour tsunami propagation simulation and amplitude forecast for Chinese coast can be completed within 90 s by using GPU parallel method. The system is validated by 9 major historical tsunamis induced by submarine earthquakes with Mw more than 8.0 in the Pacific region since 2006 with abundant observations. The results indicate that the linear shallow water model is capable of simulating the tsunami propagation in the ocean. And the Green's law basically can be used for amplitude estimation in the coastal region under the condition of slow-varying topography and open coastline with no complex geometry. Forecasting accuracy of threat levels is acceptable in terms of tsunami warning purpose, with 80% of results falling into the corresponding levels. The evaluation also confirms that the forecasting system can meet the requirement of tsunami warning in Chinese coastal areas. Note that near-field amplitude may have large deviations because of its sensitivity to tsunami source. In order to further improve the accuracy of quantitative warning of tsunami amplitude, we need to strengthen the research and operational practice from the following aspects:one is to improve the precision of the tsunami source by using method of multiple-data joint inversion; the second is to validate the feasibility of Green's law, or to construct refined and high-efficiency tsunami forecast model in coastal regions.
Based on linear shallow water equation and tsunami amplitude Green's law, a rapid earthquake induced tsunami amplitude forecast system covering the Pacific Ocean is developed. Thirty-two hour tsunami propagation simulation and amplitude forecast for Chinese coast can be completed within 90 s by using GPU parallel method. The system is validated by 9 major historical tsunamis induced by submarine earthquakes with Mw more than 8.0 in the Pacific region since 2006 with abundant observations. The results indicate that the linear shallow water model is capable of simulating the tsunami propagation in the ocean. And the Green's law basically can be used for amplitude estimation in the coastal region under the condition of slow-varying topography and open coastline with no complex geometry. Forecasting accuracy of threat levels is acceptable in terms of tsunami warning purpose, with 80% of results falling into the corresponding levels. The evaluation also confirms that the forecasting system can meet the requirement of tsunami warning in Chinese coastal areas. Note that near-field amplitude may have large deviations because of its sensitivity to tsunami source. In order to further improve the accuracy of quantitative warning of tsunami amplitude, we need to strengthen the research and operational practice from the following aspects:one is to improve the precision of the tsunami source by using method of multiple-data joint inversion; the second is to validate the feasibility of Green's law, or to construct refined and high-efficiency tsunami forecast model in coastal regions.
2019, 41(2): 14-30.
doi: 10.3969/j.issn.0253-4193.2019.02.002
Abstract:
U-boundary of the South China Sea (short name as U-boundary of SCS) is China's sea boundaries. Based on GIS and various remote sensing data, this paper studies the terrain and marine eco-environment of the U-boundary for the first time, mainly analyzing water depth and environmental characteristics, and presenting the three-dimensional characteristics of water depth distribution of the U-boundary. This study divides the U-boundary into five zones:the northeastern zone (NE), northwestern zone (NW), eastern zone (E), western zone (W), and southern zone (S) according to the terrain characteristics. In the NW and S, the terrains are gentle (<1 000 m); the W with the peak distribution is 2 303 m in average. The water depth in the E is over 2 000 m with an increase from south to north. The water depth of the NE is trough and the deepest water reaches 3 535 m. The study shows that the topography of NW, W, S, E and NE of the U-boundary are consistent with the Beibu Gulf Basin, the Vietnam East Fault, the Zengmu Basin, the South China Sea Trough, and Manila Trench respectively. The results show the impact of monsoon on the seasonal variations in the 5 zones of the U-boundary:in the NW and NE of the U-boundary, the sea surface temperature (SST) is the highest in summer, with high variation and the mixed layer depth are deepest in winter and lowest in spring while the seasonal variation of sea surface currents (SSCs) and sea surface salinity (SSS) are small. But in the NW, concentration of chlorophyll a blooms in winter and presents logarithmic distribution in other seasons, while that increase slightly in the middle of the NE in winter. The seasonal variations of SST in the W, S and E are small, while the seasonal variations of the sea surface wind field (SSW) and the mixed layer depth (MLD) are the strongest in winter but the weakest in spring. But the seasonal variation of the sea surface chlorophyll a concentration (Chl a) in the W is small while that in the middle of the S increases significantly in winter, and that in the south of the E increases slightly in winter. Marine factors in NW and S (shallow terrain) show the same seasonal distribution, especially the high Chl a in both NW and S zones in winter. The study also reveals the regional characteristics of the marine environments among 5 zones of the U-boundary. The largest seasonal variations in the SST and Chl a occur in NW zone while the largest seasonal change of the MLD appears in W zone and the largest seasonal change of the SSCs occurs in S zone. And the largest seasonal variation in the SSS is found in the E zone while a large change in the SSCs but a small seasonal variation in the Chl a is found in the NE zone. The temporal and spatial distributions of typhoon on the U-boundary are different from north to south, and its distribution is not uniform. A total of 604 typhoons crossed the U-boundary, with an average of 8 per year from 1945 to 2016. The paths concentrate in the NE, NW and E zones. 537 typhoons crossed the U-boundary within the east of 112.3° E, while 415 typhoons crossed the U-boundary within the west of 112.3° E. The ecological environments of the NE zone are greatly influenced by "Wind Pump Effect" caused by typhoon. 1991 to 2000 is a typhoon-prone period, with an average of 11 typhoons across the U-boundary. In this study, the proposed method of dividing the U-boundary in the SCS into 5 zones based on its topographical features has important scientific and practical significance.
U-boundary of the South China Sea (short name as U-boundary of SCS) is China's sea boundaries. Based on GIS and various remote sensing data, this paper studies the terrain and marine eco-environment of the U-boundary for the first time, mainly analyzing water depth and environmental characteristics, and presenting the three-dimensional characteristics of water depth distribution of the U-boundary. This study divides the U-boundary into five zones:the northeastern zone (NE), northwestern zone (NW), eastern zone (E), western zone (W), and southern zone (S) according to the terrain characteristics. In the NW and S, the terrains are gentle (<1 000 m); the W with the peak distribution is 2 303 m in average. The water depth in the E is over 2 000 m with an increase from south to north. The water depth of the NE is trough and the deepest water reaches 3 535 m. The study shows that the topography of NW, W, S, E and NE of the U-boundary are consistent with the Beibu Gulf Basin, the Vietnam East Fault, the Zengmu Basin, the South China Sea Trough, and Manila Trench respectively. The results show the impact of monsoon on the seasonal variations in the 5 zones of the U-boundary:in the NW and NE of the U-boundary, the sea surface temperature (SST) is the highest in summer, with high variation and the mixed layer depth are deepest in winter and lowest in spring while the seasonal variation of sea surface currents (SSCs) and sea surface salinity (SSS) are small. But in the NW, concentration of chlorophyll a blooms in winter and presents logarithmic distribution in other seasons, while that increase slightly in the middle of the NE in winter. The seasonal variations of SST in the W, S and E are small, while the seasonal variations of the sea surface wind field (SSW) and the mixed layer depth (MLD) are the strongest in winter but the weakest in spring. But the seasonal variation of the sea surface chlorophyll a concentration (Chl a) in the W is small while that in the middle of the S increases significantly in winter, and that in the south of the E increases slightly in winter. Marine factors in NW and S (shallow terrain) show the same seasonal distribution, especially the high Chl a in both NW and S zones in winter. The study also reveals the regional characteristics of the marine environments among 5 zones of the U-boundary. The largest seasonal variations in the SST and Chl a occur in NW zone while the largest seasonal change of the MLD appears in W zone and the largest seasonal change of the SSCs occurs in S zone. And the largest seasonal variation in the SSS is found in the E zone while a large change in the SSCs but a small seasonal variation in the Chl a is found in the NE zone. The temporal and spatial distributions of typhoon on the U-boundary are different from north to south, and its distribution is not uniform. A total of 604 typhoons crossed the U-boundary, with an average of 8 per year from 1945 to 2016. The paths concentrate in the NE, NW and E zones. 537 typhoons crossed the U-boundary within the east of 112.3° E, while 415 typhoons crossed the U-boundary within the west of 112.3° E. The ecological environments of the NE zone are greatly influenced by "Wind Pump Effect" caused by typhoon. 1991 to 2000 is a typhoon-prone period, with an average of 11 typhoons across the U-boundary. In this study, the proposed method of dividing the U-boundary in the SCS into 5 zones based on its topographical features has important scientific and practical significance.
2019, 41(2): 31-40.
doi: 10.3969/j.issn.0253-4193.2019.02.003
Abstract:
The distributions of total nitrogen (TN), C/N, and nitrogen stable isotope ratio (δ15N) in surface sediments are first studied in the Yellow Sea and East China Sea. The content of TN in surface sediment ranges from 0.023% to 0.33%, while C/N and δ15N are about 1.4-50.3 and 4.0‰-16.0‰ respectively. Significant negative correlation exists between TN and C/N, and no correlation is found between TN and δ15N or between C/N and δ15N. These relationships reflect the complexity of the nitrogen cycles in the Yellow Sea and the East China Sea, both belonging to typical continental shelf marginal sea. Then, three sediment cores collected from the southern Yellow Sea were analyzed for TN, C/N and δ15N values. And the long-term change trends of TN, C/N and δ15N were subsequently rebuilt combing with 210Pb chronological study. The results indicate that the long-term changes of TN, C/N and δ15N show some periodical trends. The temporal changes of TN show similar change trends in the three sea areas, with generally increasing trends over the past 100 years. And C/N trends also follow relatively similar patterns in the three sediment cores, while the average cycle of δ15N is about 24 years. Finally, the historical changes of nutrient usability in the upper water of the southern Yellow Sea over the past 200 years are reconstructed, and their responses to climate change are discussed preliminarily.
The distributions of total nitrogen (TN), C/N, and nitrogen stable isotope ratio (δ15N) in surface sediments are first studied in the Yellow Sea and East China Sea. The content of TN in surface sediment ranges from 0.023% to 0.33%, while C/N and δ15N are about 1.4-50.3 and 4.0‰-16.0‰ respectively. Significant negative correlation exists between TN and C/N, and no correlation is found between TN and δ15N or between C/N and δ15N. These relationships reflect the complexity of the nitrogen cycles in the Yellow Sea and the East China Sea, both belonging to typical continental shelf marginal sea. Then, three sediment cores collected from the southern Yellow Sea were analyzed for TN, C/N and δ15N values. And the long-term change trends of TN, C/N and δ15N were subsequently rebuilt combing with 210Pb chronological study. The results indicate that the long-term changes of TN, C/N and δ15N show some periodical trends. The temporal changes of TN show similar change trends in the three sea areas, with generally increasing trends over the past 100 years. And C/N trends also follow relatively similar patterns in the three sediment cores, while the average cycle of δ15N is about 24 years. Finally, the historical changes of nutrient usability in the upper water of the southern Yellow Sea over the past 200 years are reconstructed, and their responses to climate change are discussed preliminarily.
2019, 41(2): 41-51.
doi: 10.3969/j.issn.0253-4193.2019.02.004
Abstract:
In this paper, we analyze different forms of barium, biogenic silica, the organic carbon (OC), total nitrogen concentrations and their stable isotopic compositions (δ13C and δ15N) in two short sediment cores sampled from the northern South China Sea (SCS). The results show that the detrital and biogenic barium are the main forms of barium in sediments. Based on the sequential extraction leaching, the biogenic barium content in sediments is between 10.3 μg/g and 385.2 μg/g with an average of 177.0 μg/g. Estimated the past productivity using the biogenic barium is between 12.3 mg/(d·m2) and 146.7 mg/(d·m2) with an average of 78.9 mg/(d·m2), and is comparable with the modern values near D06 station. The stratigraphic profiles of OC concentration, OC/TN ratios, δ13C and δ15N for the past about 400 years indicate that these two cores display distinctive histories. The δ13C values of sedimentary organic matter changed between -22.98‰ and -20.73‰. The relatively narrow δ13C range of sedimentary organic carbon with a mean value close to -21.46‰ indicates that the sedimentary organic matter is derived from marine phytoplankton mainly. Based on a two-end member mixing model, the estimated terrestrial organic matter is up to 41.3% at site S0612 and 11% at site D06 respectively. The δ15N values of sediments range from 5.92‰ to 6.29‰ with an average of (6.08±0.12)‰ for D06, and 3.96‰ to 4.85‰ with an average of (4.32±0.26)‰ for S0612 respectively. The low δ15N values may reflect that nitrogen fixation was more important for the new nitrogen supply and the source of ntritate from north Pacific intermediate water, and was not affected by nitrate utilization.
In this paper, we analyze different forms of barium, biogenic silica, the organic carbon (OC), total nitrogen concentrations and their stable isotopic compositions (δ13C and δ15N) in two short sediment cores sampled from the northern South China Sea (SCS). The results show that the detrital and biogenic barium are the main forms of barium in sediments. Based on the sequential extraction leaching, the biogenic barium content in sediments is between 10.3 μg/g and 385.2 μg/g with an average of 177.0 μg/g. Estimated the past productivity using the biogenic barium is between 12.3 mg/(d·m2) and 146.7 mg/(d·m2) with an average of 78.9 mg/(d·m2), and is comparable with the modern values near D06 station. The stratigraphic profiles of OC concentration, OC/TN ratios, δ13C and δ15N for the past about 400 years indicate that these two cores display distinctive histories. The δ13C values of sedimentary organic matter changed between -22.98‰ and -20.73‰. The relatively narrow δ13C range of sedimentary organic carbon with a mean value close to -21.46‰ indicates that the sedimentary organic matter is derived from marine phytoplankton mainly. Based on a two-end member mixing model, the estimated terrestrial organic matter is up to 41.3% at site S0612 and 11% at site D06 respectively. The δ15N values of sediments range from 5.92‰ to 6.29‰ with an average of (6.08±0.12)‰ for D06, and 3.96‰ to 4.85‰ with an average of (4.32±0.26)‰ for S0612 respectively. The low δ15N values may reflect that nitrogen fixation was more important for the new nitrogen supply and the source of ntritate from north Pacific intermediate water, and was not affected by nitrate utilization.
2019, 41(2): 52-62.
doi: 10.3969/j.issn.0253-4193.2019.02.005
Abstract:
Based on the sediment dating, we studied the historical changes of biogenic elements, carbon, nitrogen and phosphorus, in the sediment of Kuroshio mainstream, east of Taiwan, and investigated the sedimentary record of climatic and environmental changes for nearly one thousand years. The results show that the sedimentation rate of Kuroshio mainstream, east of Taiwan and south slope of Ryukyu Arc, is up to 34.2 cm/ka. Three stages could be roughly divided according to the sedimentation rates, which are basically the same with the division of Medieval Warm Period (MWP), Little Ice Age (LIA) and Current Warm Period (CWP). The carbon in the sediment is mainly inorganic, and the total inorganic carbon (TIC) gradually increases with great variation from 1850 AD, which exactly corresponds to the rapid rise of atmospheric CO2. The variation of total organic carbon (TOC), however, is closely related to the change of East Asian Summer Monsoon (EASM) intensity. The EASM was weaker in LIA than in MWP and CWP, meanwhile the TOC content of the sediment in LIA is higher. That is because weaker EASM is conducive to the generation and transportation of wind dust from the Asian continent, which could supply nutrients and promote the primary productivity of relevant seas. From 1850 AD, the C:N:P ratios in the sediment gradually increases to higher than the Redfield ratio, which means the nutrient structure changed from N-depleted to N-abundant. This change is closely related to the rapid increase of nitrogen emissions in modern times. Overall, the biogenic indexes in the Kuroshio mainstream sediment clearly record and well respond to the climatic and environmental changes over the past millennium, especially the drastic environmental change caused by intensive human activities over the past 150 a.
Based on the sediment dating, we studied the historical changes of biogenic elements, carbon, nitrogen and phosphorus, in the sediment of Kuroshio mainstream, east of Taiwan, and investigated the sedimentary record of climatic and environmental changes for nearly one thousand years. The results show that the sedimentation rate of Kuroshio mainstream, east of Taiwan and south slope of Ryukyu Arc, is up to 34.2 cm/ka. Three stages could be roughly divided according to the sedimentation rates, which are basically the same with the division of Medieval Warm Period (MWP), Little Ice Age (LIA) and Current Warm Period (CWP). The carbon in the sediment is mainly inorganic, and the total inorganic carbon (TIC) gradually increases with great variation from 1850 AD, which exactly corresponds to the rapid rise of atmospheric CO2. The variation of total organic carbon (TOC), however, is closely related to the change of East Asian Summer Monsoon (EASM) intensity. The EASM was weaker in LIA than in MWP and CWP, meanwhile the TOC content of the sediment in LIA is higher. That is because weaker EASM is conducive to the generation and transportation of wind dust from the Asian continent, which could supply nutrients and promote the primary productivity of relevant seas. From 1850 AD, the C:N:P ratios in the sediment gradually increases to higher than the Redfield ratio, which means the nutrient structure changed from N-depleted to N-abundant. This change is closely related to the rapid increase of nitrogen emissions in modern times. Overall, the biogenic indexes in the Kuroshio mainstream sediment clearly record and well respond to the climatic and environmental changes over the past millennium, especially the drastic environmental change caused by intensive human activities over the past 150 a.
2019, 41(2): 63-74.
doi: 10.3969/j.issn.0253-4193.2019.02.006
Abstract:
32Si generates from the spallation reaction of cosmic rays and argon in atmosphere, which is ingested by siliceous organisms such as diatoms after falling into the lakes and sea from atmosphere. The cosmogenic radioactive isotope 32Si, with a half-life of approximately 150 a, represents an excellent dating tool for the age range of approximately 100-1 000 a. 32Si, with a single source and a constant production rate, is of importance to the ancient environments and paleoclimatology. The method of determining 32Si activity in the marine sediments was established. The main steps were as follows:(1) sample pretreatment; (2) separating and purifying biogenic silica; (3) separating and purifying phosphorus from biogenic silica; (4) preparation of phosphorus and counting 32P by β counter. The experimental process was monitored by acidic silicomolybdenum blue spectrophotometry and phosphomolybdenum blue spectrophotometry to control loss of silicon and phosphorus during the process. The specific activity of 32Si in sediments from Nansha sea area varies from 8.39 mBq/kg to 33.34 mBq/kg, with 16.60 mBq/kg as the mean value. The average specific activity of 32Si in SiO2 is 0.356 Bq/kg. The average specific abundance of 32Si in biogenic silica is 1.29×10-16 (32Si/SiO2). Sedimentary rates of sediment cores from deep water (1 335-1 537 m) and shallow water (121-141 m) are 0.106 cm/a and 0.191 cm/a respectively. The average setting flux of 32Si is 2.14×10-6 Bq/(cm2·a), within the range of references.
32Si generates from the spallation reaction of cosmic rays and argon in atmosphere, which is ingested by siliceous organisms such as diatoms after falling into the lakes and sea from atmosphere. The cosmogenic radioactive isotope 32Si, with a half-life of approximately 150 a, represents an excellent dating tool for the age range of approximately 100-1 000 a. 32Si, with a single source and a constant production rate, is of importance to the ancient environments and paleoclimatology. The method of determining 32Si activity in the marine sediments was established. The main steps were as follows:(1) sample pretreatment; (2) separating and purifying biogenic silica; (3) separating and purifying phosphorus from biogenic silica; (4) preparation of phosphorus and counting 32P by β counter. The experimental process was monitored by acidic silicomolybdenum blue spectrophotometry and phosphomolybdenum blue spectrophotometry to control loss of silicon and phosphorus during the process. The specific activity of 32Si in sediments from Nansha sea area varies from 8.39 mBq/kg to 33.34 mBq/kg, with 16.60 mBq/kg as the mean value. The average specific activity of 32Si in SiO2 is 0.356 Bq/kg. The average specific abundance of 32Si in biogenic silica is 1.29×10-16 (32Si/SiO2). Sedimentary rates of sediment cores from deep water (1 335-1 537 m) and shallow water (121-141 m) are 0.106 cm/a and 0.191 cm/a respectively. The average setting flux of 32Si is 2.14×10-6 Bq/(cm2·a), within the range of references.
2019, 41(2): 75-84.
doi: 10.3969/j.issn.0253-4193.2019.02.007
Abstract:
The clay minerals of 13 surface sediments and 168 modern sediments of 4 sediment cores in Daling River and Liaohe River were analyzed with the X-ray diffraction method. The results show that smectite-illite-kaolinite-chlorite is the main clay mineral assemblage of Daling River sediments, while the main assemblage of Liaohe River is illite-smectite-chlorite-kaolinite. The most ratios of smectite content to illite content of Daling River are greater than 1, while the ratio values of Liaohe River are less than 1. It is clear that the two river sediments are distinguished by the triangular map with end members of illite, smectite, and kaolinite+chlorite (ISKc). Clay minerals can be used as a discriminative index of the two river sediments. The results reveal similar degrees of physical weathering in Daling River Basin and Liaohe River Basin, and a slight intensity in Liaohe River Basin. The geological background and climatic conditions in the basins result in the difference in the composition of clay minerals in the sediments of the Daling River and Liaohe River.
The clay minerals of 13 surface sediments and 168 modern sediments of 4 sediment cores in Daling River and Liaohe River were analyzed with the X-ray diffraction method. The results show that smectite-illite-kaolinite-chlorite is the main clay mineral assemblage of Daling River sediments, while the main assemblage of Liaohe River is illite-smectite-chlorite-kaolinite. The most ratios of smectite content to illite content of Daling River are greater than 1, while the ratio values of Liaohe River are less than 1. It is clear that the two river sediments are distinguished by the triangular map with end members of illite, smectite, and kaolinite+chlorite (ISKc). Clay minerals can be used as a discriminative index of the two river sediments. The results reveal similar degrees of physical weathering in Daling River Basin and Liaohe River Basin, and a slight intensity in Liaohe River Basin. The geological background and climatic conditions in the basins result in the difference in the composition of clay minerals in the sediments of the Daling River and Liaohe River.
2019, 41(2): 85-98.
doi: 10.3969/j.issn.0253-4193.2019.02.008
Abstract:
Microplastic particles, defined as plastic particles smaller than 5 mm, are derived from the fragmentation of larger debris or enter the environment directly as microplastic fragments. The pathways of microplastic ingested by marine organisms and its effects to marine ecosystem have aroused worldwide attention. This review discusses the sources, types and distributions of microplastic in marine environment stress that there are plastic particles floating on coastal and marine environment in the world, while in China, coastal areas are the main polluted areas. Microplastic particles threat various marine organisms including fish. The main pathway that marine fish accumulate microplastic is ingestion by mistake. Plastic particles are mainly found in the digestive tract of several fish species. The ecotoxicological effects of microplastic on fish include:decrease survival, affect development and reproduction, disturb behavior, lead to tissue lesion and inflammatory reaction, cause metabolic disorder, damage nervous system, induce oxidative stress and interrupt endocrine. In the future, several aspects need to take more attentions on the effects of microplastic research, especially the difference between microplastic used in laboratory experiment and natural environment, such as concentrations, shape and size. Furthermore, international cooperation should be strengthened for observing the migration and transformation pathway of microplastic in marine ecosystem as well as investigating the ecological effects of microplastic and their internal mechanisms on marine organisms and ecosystem. Meanwhile, the joint toxicity of microplastic with other marine pollutants should be valued and its interactive effects with global climate change, such as high tempeture, ocean acidification and hypoxia should be further investigated.
Microplastic particles, defined as plastic particles smaller than 5 mm, are derived from the fragmentation of larger debris or enter the environment directly as microplastic fragments. The pathways of microplastic ingested by marine organisms and its effects to marine ecosystem have aroused worldwide attention. This review discusses the sources, types and distributions of microplastic in marine environment stress that there are plastic particles floating on coastal and marine environment in the world, while in China, coastal areas are the main polluted areas. Microplastic particles threat various marine organisms including fish. The main pathway that marine fish accumulate microplastic is ingestion by mistake. Plastic particles are mainly found in the digestive tract of several fish species. The ecotoxicological effects of microplastic on fish include:decrease survival, affect development and reproduction, disturb behavior, lead to tissue lesion and inflammatory reaction, cause metabolic disorder, damage nervous system, induce oxidative stress and interrupt endocrine. In the future, several aspects need to take more attentions on the effects of microplastic research, especially the difference between microplastic used in laboratory experiment and natural environment, such as concentrations, shape and size. Furthermore, international cooperation should be strengthened for observing the migration and transformation pathway of microplastic in marine ecosystem as well as investigating the ecological effects of microplastic and their internal mechanisms on marine organisms and ecosystem. Meanwhile, the joint toxicity of microplastic with other marine pollutants should be valued and its interactive effects with global climate change, such as high tempeture, ocean acidification and hypoxia should be further investigated.
2019, 41(2): 99-106.
doi: 10.3969/j.issn.0253-4193.2019.02.009
Abstract:
Spotted mackerel (Scomber australasicus) is an important pelagic and economic species in northwest Pacific. The life cycle is relatively short, and the stock resources is obviously affected by the recruitment. It is important to know the recruitment of spotted mackerel for the stock resources and sustainable utilization. The data include 6 factors which are sea surface temperature of first spawning ground (SST1), sea surface temperature of second spawning ground(SST2), sea surface temperature of feeding ground (SST3), tidal range (TR), Pacific decadal oscillation(PDO) and spawning stock biomass(SSB), all factors and recruitment are used to build the forecasting model. The Bayesian model averaging (BMA) not only give us the importance of the factors in explaining the recruitment, but also can predict the recruitment. The result shows the spawning stock biomass is most important factor for recruitment with long and stable explanatory ability, the second is SST3, which may be due to the fact that supplemental groups lived longer in the feeding grounds and the temperature of the feeding grounds had a greater impact on the growth and survival of larvae or eggs. Meanwhile, PDO, TR, SST2 and SST1 are also important for recruitment models. The forecast, based on BMA which takes the advantages of each model into consideration, is better than single models, and can be used for the recruitment prediction of spotted mackerel.
Spotted mackerel (Scomber australasicus) is an important pelagic and economic species in northwest Pacific. The life cycle is relatively short, and the stock resources is obviously affected by the recruitment. It is important to know the recruitment of spotted mackerel for the stock resources and sustainable utilization. The data include 6 factors which are sea surface temperature of first spawning ground (SST1), sea surface temperature of second spawning ground(SST2), sea surface temperature of feeding ground (SST3), tidal range (TR), Pacific decadal oscillation(PDO) and spawning stock biomass(SSB), all factors and recruitment are used to build the forecasting model. The Bayesian model averaging (BMA) not only give us the importance of the factors in explaining the recruitment, but also can predict the recruitment. The result shows the spawning stock biomass is most important factor for recruitment with long and stable explanatory ability, the second is SST3, which may be due to the fact that supplemental groups lived longer in the feeding grounds and the temperature of the feeding grounds had a greater impact on the growth and survival of larvae or eggs. Meanwhile, PDO, TR, SST2 and SST1 are also important for recruitment models. The forecast, based on BMA which takes the advantages of each model into consideration, is better than single models, and can be used for the recruitment prediction of spotted mackerel.
2019, 41(2): 107-113.
doi: 10.3969/j.issn.0253-4193.2019.02.010
Abstract:
According to the survied data of nano- and microzooplankton in the Kongsfjorden area of Svalbard in August 2017, the species composition and community characteristics of nano- and microzooplankton in the region were analyzed. The results show that there is a clear thermodynamic layer in the Kongsfjorden area in the water depth of 10-50 m, which is higher than that of other water layers. The salinity gradually increases from the surface to the bottom, and the salinity of 70 m is basically stable in the deep sea. Nano- and microzooplankton includes three categories:Aloricate Ciliates, Tintinnida Ciliates and Crustacea Nauplii. Tintinnida Ciliates include 10 species. Ptychocylis obtuse, Acanthostomella norvegica, Favella sp., Tintinnopsis beroidea and Stenosemella nivalis are dominant species. Nano- and microzooplankton mainly distributes in the upper water. Species and abundance are rich in 10-30 m water layer. Nano- and microzooplankton abundance accounts for about 54.8% in upper 30 m water layers. And it's more than 93% in the above 100 m water layers. The most of abundance of nano- and microzooplankton (the mean is 343.3 ind./L) is in the 10 m layer, and the lowest (the mean is 50.9 ind./L) is in the bottom. The biodiversity is generally preferable and the differences between different sites are slight.
According to the survied data of nano- and microzooplankton in the Kongsfjorden area of Svalbard in August 2017, the species composition and community characteristics of nano- and microzooplankton in the region were analyzed. The results show that there is a clear thermodynamic layer in the Kongsfjorden area in the water depth of 10-50 m, which is higher than that of other water layers. The salinity gradually increases from the surface to the bottom, and the salinity of 70 m is basically stable in the deep sea. Nano- and microzooplankton includes three categories:Aloricate Ciliates, Tintinnida Ciliates and Crustacea Nauplii. Tintinnida Ciliates include 10 species. Ptychocylis obtuse, Acanthostomella norvegica, Favella sp., Tintinnopsis beroidea and Stenosemella nivalis are dominant species. Nano- and microzooplankton mainly distributes in the upper water. Species and abundance are rich in 10-30 m water layer. Nano- and microzooplankton abundance accounts for about 54.8% in upper 30 m water layers. And it's more than 93% in the above 100 m water layers. The most of abundance of nano- and microzooplankton (the mean is 343.3 ind./L) is in the 10 m layer, and the lowest (the mean is 50.9 ind./L) is in the bottom. The biodiversity is generally preferable and the differences between different sites are slight.
2019, 41(2): 114-122.
doi: 10.3969/j.issn.0253-4193.2019.02.011
Abstract:
In order to obtain the artificial pigmentation mutants, a certain dose of ultraviolet ray was used to irradiate the gametophytic blades developed from conchospores of the wild-type strain in Pyropia suborbiculata. Color-mutated cells of showing light green yellow, olive, green, green brown, yellow brown, light brown, dark purple red and light purple red and other mutated colors appeared in the UV-irradiated blades after being cultured of 7 to 14 d. These color-mutated cells grew to form different color cell-clusters after being cultured for an additional 2 to 3 weeks. The frequency of appearing color-mutated cell-clusters on the gametophytic blades increased with increasing intensity of ultraviolet irradiation from 0-80 μW/cm2. However, as the radiation intensity increased to 100 μW/cm2, the frequency of appearing color-mutant cell-clusters decreased on gametophytic blades. These results indicate that 80 μW/cm2 is most effictive intensity of ultraviolet irradiation for inducing mutations of gametophytic blades in Pyropia suborbiculata. The color-mutated cell-clusters were cutted, placed in aerating culture bottle and cultured, until they released monospores. The nylon cotton thread was placed into aerating culture bottle and used for monospores adhering matrix. Monospores on the cotton thread were cultured, and germinated into blades. From the blades arising from germination of monospores, yellow brown, olive, red, brown red, and other single-colored mutant blades were selected. Subsequently, the respective genetic homozygous conchocelis (strains) were obtained using the gametophytic blades parthenogenesis. Their colors were relatively stable in both F1 gametophytic blade and conchocelis phases. The F1 gametophytic blades of each mutant strains from conchospores are the same color as the respective parent blades, indicating that the color is stably inherited. In vivo absorption spectra and contents of chlorophyll a, phycoerythrin and phycocyanin of F1 gametophytic blades from conchospores of pigmentation mutant strains and the wild-type strain in Pyropia suborbiculata were measured. The results show that, compared with wild-type strains, the growth rate, the in vivo absorption spectrum, the contents of the three main photosynthetic pigments and pigment proteins, and their ratios to each other are changed significantly in the F1 gametophytic blades of each pigmentation mutant strains.
In order to obtain the artificial pigmentation mutants, a certain dose of ultraviolet ray was used to irradiate the gametophytic blades developed from conchospores of the wild-type strain in Pyropia suborbiculata. Color-mutated cells of showing light green yellow, olive, green, green brown, yellow brown, light brown, dark purple red and light purple red and other mutated colors appeared in the UV-irradiated blades after being cultured of 7 to 14 d. These color-mutated cells grew to form different color cell-clusters after being cultured for an additional 2 to 3 weeks. The frequency of appearing color-mutated cell-clusters on the gametophytic blades increased with increasing intensity of ultraviolet irradiation from 0-80 μW/cm2. However, as the radiation intensity increased to 100 μW/cm2, the frequency of appearing color-mutant cell-clusters decreased on gametophytic blades. These results indicate that 80 μW/cm2 is most effictive intensity of ultraviolet irradiation for inducing mutations of gametophytic blades in Pyropia suborbiculata. The color-mutated cell-clusters were cutted, placed in aerating culture bottle and cultured, until they released monospores. The nylon cotton thread was placed into aerating culture bottle and used for monospores adhering matrix. Monospores on the cotton thread were cultured, and germinated into blades. From the blades arising from germination of monospores, yellow brown, olive, red, brown red, and other single-colored mutant blades were selected. Subsequently, the respective genetic homozygous conchocelis (strains) were obtained using the gametophytic blades parthenogenesis. Their colors were relatively stable in both F1 gametophytic blade and conchocelis phases. The F1 gametophytic blades of each mutant strains from conchospores are the same color as the respective parent blades, indicating that the color is stably inherited. In vivo absorption spectra and contents of chlorophyll a, phycoerythrin and phycocyanin of F1 gametophytic blades from conchospores of pigmentation mutant strains and the wild-type strain in Pyropia suborbiculata were measured. The results show that, compared with wild-type strains, the growth rate, the in vivo absorption spectrum, the contents of the three main photosynthetic pigments and pigment proteins, and their ratios to each other are changed significantly in the F1 gametophytic blades of each pigmentation mutant strains.
2019, 41(2): 123-133.
doi: 10.3969/j.issn.0253-4193.2019.02.012
Abstract:
The stick-held net is one of the main methods for the fishing of saury (Cololabis saira), which is being rapidly promoted due to the high catch rate. Model tests and on-sea surveys are the two most common ways to study the performance of the fishing gear. The comparative evaluation of the two test results is of great significance for the better determination of the net workability. Based on the model net test of stick-held net in November-December 2014 and the on-sea measurement of stick-held net at the "Lupengyuanyu 019" in July-October 2015 and June-October 2016, the method of multivariate linear regression is used to standardize the sinking depth and speed of the rising. Bootstrap method is used to analyze the experimental model of the rigging and the measured results at sea. The results show that:(1) The mean distribution range of normalized maximal sinking depth is 20.37-29.54 m and the 95% confidence interval is 21.76-28.13 m by Bootstrap method. The range of the maximum sinking depth of the model net is 26.42-37.58 m, 95% confidence interval is 27.70-36.20 m. The average net sinking depth of the measured network with the central part is about 0.731-0.783 times the average maximum sinking depth of the central part of the model network. (2) According to the Bootstrap method, the average velocity of the measured network is 0.107-0.193 m/s and the 95% confidence interval is 0.111-0.191 m/s. The range of the model network with the average speed of ascension is 0.204-0.316 m/s, 95% confidence interval is 0.207-0.312 m/s. Measured network with the central upgrade speed is about the average model network with the central upgrade speed of 0.591-0.611 times. (3) When the current velocity is assumed to be 0, the average sinking depth of the measured network is calculated as 29.14-41.21 m, which is about 0.751-0.807 times of the average maximum sinking depth of the model network. (4) Both the current velocity of 30 m and the depth of 60 m have an impact on the settlement depth of the middle part of the physical net, and the influence of the flow velocity at the depth of 60 m is more significant (P<0.05).
The stick-held net is one of the main methods for the fishing of saury (Cololabis saira), which is being rapidly promoted due to the high catch rate. Model tests and on-sea surveys are the two most common ways to study the performance of the fishing gear. The comparative evaluation of the two test results is of great significance for the better determination of the net workability. Based on the model net test of stick-held net in November-December 2014 and the on-sea measurement of stick-held net at the "Lupengyuanyu 019" in July-October 2015 and June-October 2016, the method of multivariate linear regression is used to standardize the sinking depth and speed of the rising. Bootstrap method is used to analyze the experimental model of the rigging and the measured results at sea. The results show that:(1) The mean distribution range of normalized maximal sinking depth is 20.37-29.54 m and the 95% confidence interval is 21.76-28.13 m by Bootstrap method. The range of the maximum sinking depth of the model net is 26.42-37.58 m, 95% confidence interval is 27.70-36.20 m. The average net sinking depth of the measured network with the central part is about 0.731-0.783 times the average maximum sinking depth of the central part of the model network. (2) According to the Bootstrap method, the average velocity of the measured network is 0.107-0.193 m/s and the 95% confidence interval is 0.111-0.191 m/s. The range of the model network with the average speed of ascension is 0.204-0.316 m/s, 95% confidence interval is 0.207-0.312 m/s. Measured network with the central upgrade speed is about the average model network with the central upgrade speed of 0.591-0.611 times. (3) When the current velocity is assumed to be 0, the average sinking depth of the measured network is calculated as 29.14-41.21 m, which is about 0.751-0.807 times of the average maximum sinking depth of the model network. (4) Both the current velocity of 30 m and the depth of 60 m have an impact on the settlement depth of the middle part of the physical net, and the influence of the flow velocity at the depth of 60 m is more significant (P<0.05).
2019, 41(2): 134-144.
doi: 10.3969/j.issn.0253-4193.2019.02.013
Abstract:
Based on the water environment monitoring data in August,2005-2011 and in May, August,2012-2015, principal component analysis result of water quality index is applied to divide the environmental units in the bays of Fujian Province, then characteristics of bays of Fujian Province water quality are analyzed by the time-space matrix method. The results show that, (1) through principal component analysis, four water quality indexes are clustered into 2 types of components:Phosphate and chlorophyll a are clustered into one principal component, and nitrate and dissolved oxygen are clustered into another principal component; (2) the weight value as the coordinates, the surface water of bays of Fujian Province is divided into six environment units, and the time series matrix of relative content of water quality index is established in order to analyze water quality condition on bays of Fujian Province; (3) the time-space matrix of water quality index shows the certain cycle trend; index changing pattern of adjacent environment unit is synchronous; the absolute value of index change content increases slightly from chlorophyll a to nutrient salt to dissolved oxygen; (4) two principal components have a certain correlation, nutrition level influence nutrient-phytoplankton dynamics, when the phosphate content is higher than 0.03 mg/L, the nitrate content is higher than 0.25 mg/L and the nutrient cycle time changes significantly,a linkage effect on the comparative changes of nutrient and chlorophyll a; (5) the water productivity of bays of Fujian Province is low in summer, at the same time, a large amount of organic matter is inputted and degraded, the content of dissolved oxygen in surface layer decreases obviously; (6) the water environmental condition in bays of Fujian Province is influenced by two different kinds of water bodies,one is the river runoff enriched in high nutrient, which affect the environmental units of the estuaries and adjacent sea areas; the southern bays of Fujian Province is mainly affected by the Taiwan warm current and upwelling, which is an important source of phosphate in the East China Sea.
Based on the water environment monitoring data in August,2005-2011 and in May, August,2012-2015, principal component analysis result of water quality index is applied to divide the environmental units in the bays of Fujian Province, then characteristics of bays of Fujian Province water quality are analyzed by the time-space matrix method. The results show that, (1) through principal component analysis, four water quality indexes are clustered into 2 types of components:Phosphate and chlorophyll a are clustered into one principal component, and nitrate and dissolved oxygen are clustered into another principal component; (2) the weight value as the coordinates, the surface water of bays of Fujian Province is divided into six environment units, and the time series matrix of relative content of water quality index is established in order to analyze water quality condition on bays of Fujian Province; (3) the time-space matrix of water quality index shows the certain cycle trend; index changing pattern of adjacent environment unit is synchronous; the absolute value of index change content increases slightly from chlorophyll a to nutrient salt to dissolved oxygen; (4) two principal components have a certain correlation, nutrition level influence nutrient-phytoplankton dynamics, when the phosphate content is higher than 0.03 mg/L, the nitrate content is higher than 0.25 mg/L and the nutrient cycle time changes significantly,a linkage effect on the comparative changes of nutrient and chlorophyll a; (5) the water productivity of bays of Fujian Province is low in summer, at the same time, a large amount of organic matter is inputted and degraded, the content of dissolved oxygen in surface layer decreases obviously; (6) the water environmental condition in bays of Fujian Province is influenced by two different kinds of water bodies,one is the river runoff enriched in high nutrient, which affect the environmental units of the estuaries and adjacent sea areas; the southern bays of Fujian Province is mainly affected by the Taiwan warm current and upwelling, which is an important source of phosphate in the East China Sea.
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