The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single f...The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.展开更多
Temporal and spatial variations of concentrations of heavy metals including mercury (Hg), zinc (Zn), lead (Pb), arsenic (As), copper (Cu), and cadmium (Cd) in the sediments of the Yangshan Deepwater Harbor...Temporal and spatial variations of concentrations of heavy metals including mercury (Hg), zinc (Zn), lead (Pb), arsenic (As), copper (Cu), and cadmium (Cd) in the sediments of the Yangshan Deepwater Harbor were determined based on 6 cruises in autumn and winter, respectively, from 2010 to 2013. The results demonstrated that the overall concentrations of heavy metals were low and distributed in uniform patterns. The concentrations of Hg, Zn, Pb, and Cd in autumn were significantly higher than those in winter with small fluctuations for As and Cu in terms of seasonal variations. Results of factor analysis showed that Pb, Cd, and Zn were derived from inland industrial and shipping discharges as well as the degradation of organic pollutants in marine environment. While agricultural pollutions, cargo shifting and construction debris from reclamation projects contributed to the sources of Cu, As, and Hg. Ecological risk assessment by Mean Sediment Quality Guideline Quotient (SQG-Q) revealed that the degree for eco-risk of the sediments was low-and-moderate in autumn, higher than that in winter. Hg and Cu were the dominant eco-risk factors. The results of Index of geoaccumulation (Igeo) showed that the whole sites of the sea area were barely influenced by Hg, As, Zn, and Pb, and the extents of Cd and Cu contaminations were in low grade. Contamination degree of all the six heavy metals could be ranked as the following: Cd〉Pb〉Zn〉Hg〉As. According to the results of integrated score of factor analysis, the contamination degree for heavy metals in sediments of the Yangshan Deepwater Harbor was low, despite sites No.5, No.4 and No.3, which were heavily contaminated compared with others.展开更多
Delay-difference models are intermediate between simple surplus-production models and complicated age-structured models. Such intermediate models are more efficient and require less data than age-structured models. In...Delay-difference models are intermediate between simple surplus-production models and complicated age-structured models. Such intermediate models are more efficient and require less data than age-structured models. In this study, a delay-differ- ence model was applied to fit catch and catch per unit effort (CPUE) data (1975-2011) of the southern Atlantic albacore (Thunnus alalunga) stock. The proposed delay-difference model captures annual fluctuations in predicted CPUE data better than Fox model. In a Monte Carlo simulation, white noises (CVs) were superimposed on the observed CPUE data at four levels. Relative estimate error was then calculated to compare the estimated results with the true values of parameters a and fl in Ricker stock-recruitment model and the catchability coefficient q. a is more sensitive to CV than fl and q. We also calculated an 80% percentile confidence interval of the maximum sustainable yield (MSY, 21756 t to 23408 t; median 22490 t) with the delay-difference model. The yield of the southern Atlantic albacore stock in 2011 was 24122t, and the estimated ratios of catch against MSY for the past seven years were approxi- mately 1.0. We suggest that care should be taken to protect the albacore fishery in the southern Atlantic Ocean. The proposed de- lay-difference model provides a good fit to the data of southern Atlantic albacore stock and may be a useful choice for the assessment of regional albacore stock.展开更多
Experiments were designed to expose the filter-feeding bivalve Perna viridis to different Cd-contaminated water environments in order to compare the different pathways through which Cd is accumulated. Results show tha...Experiments were designed to expose the filter-feeding bivalve Perna viridis to different Cd-contaminated water environments in order to compare the different pathways through which Cd is accumulated. Results show that mussels can accumulate Cd through seawater, food, sediment and suspended particle pathways in a short period of time. Mussels' uptake of Cd through the seawater pathway reaches the highest concentration approximately 3 and 9 times larger than through the algae and sediment pathways respectively after 7 d. This indicates that the Cd-accumulation through seawater is most efficient. Results also indicate that the uptake directly through contaminated algae, particles or sediments ingested by mussels is less important when compared with the uptake of Cd by mussels through the seawater pathway. Metal uptake pathways and mechanisms of bioaccumulation by marine bivalve are also discussed in this paper.展开更多
Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sedim...Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modem lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system.展开更多
Friction stir welding provides better retention of ductility and plasticity in comparison to fusion welding and it increases the stability against cracking.This study aims to enhance both the ductility and strength of...Friction stir welding provides better retention of ductility and plasticity in comparison to fusion welding and it increases the stability against cracking.This study aims to enhance both the ductility and strength of the welded joints.Tool profile was found to play an important role in retaining ductility,understanding the metal flow behavior and determining the fracture initiating point.The microstructure of different regions in the onion ring was inferred to correlate the strength with the metal flow pattern.The onion ring pattern strengthened the weld nugget.Shoulder and taper threaded profile tool resulted in superior mechanical properties.Microhardness results confirmed that the fracture runs through low hardness areas such as heat affected zone and thermo-mechanically affected zone.The scanning electron microscopic images revealed elongated grains and dimples,justifying ductile mode of fracture.展开更多
Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese longliners during 2003,2004 and 2005,which is a part of Chinese Tuna Fishery Scientific Observer Program(CTFSOP) . The reprod...Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese longliners during 2003,2004 and 2005,which is a part of Chinese Tuna Fishery Scientific Observer Program(CTFSOP) . The reproductive biology has been investigated. A total of 1 023 samples are collected including 417 ovaries and 606 testes. Spawning activities of yellowfin tuna have been studied for both male and female from January to June. The data showed that the average monthly sex ratio is 0.59,and the minimum length at sexual maturity is 101 cm for female and 110 cm for male respectively. Length at 50% sexual maturity is esti-mated at 113.77 cm for female and 120.20 cm for male,whereas maturation rate is 0.066 cm-1 for female and 0.091 cm-1 for male. Sex ratio by length class indicates that the proportion of male is higher than female's along with size increasing;for instance,in the group of the body length longer than 145 cm,some females have their body length from 145 to 160 cm and males have their body length at 160 cm and even longer. Statistically,yellowfin tuna has a significant seasonal reproduction.展开更多
The distribution of hexachloroeyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in the surface sea- water and sediment of Jincheng Bay mariculture area were investigated in the present study. The con...The distribution of hexachloroeyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in the surface sea- water and sediment of Jincheng Bay mariculture area were investigated in the present study. The concentration of total HCHs and DDTs ranged from 2.98 to 14.87ngL-l and were〈0.032ngL-1, respectively, in surface seawater, and ranged from 5.52 to 9.43 and from 4.11 to 6.72 ng g-l, respectively, in surface sediment. It was deduced from the composition profile of HCH isomers and DDT congeners that HCH residues derived from a mixture of technical-grade HCH and lindane whereas the DDT residues derived from technical-grade DDT and dicofol. Moreover, both HCH and DDT residues may mainly originate from historical inputs. The hazard quotient of α-HCH, β-HCH, γ-HCH and δ-HCH to marine species was 0.030, 0.157, 3.008 and 0.008, respectively. It was estimated that the overall probability of adverse biological effect from HCHs was less than 5%, indicating that its risk to seawater column spe- cies was low. The threshold effect concentration exceeding frequency of γ-HCH, p,p'-DDD, p,p'-DDE and p,p'-DDT in sediment ranged from 8.3% to 100%, and the relative concentration of the HCH and DDT mixture exceeded their probable effect level in sediment. These findings indicated that the risk to marine benthos was high and potentially detrimental to the safety of aquatic prod- ucts, e.g., sea cucumber and benthic shellfish.展开更多
The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active ...The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.展开更多
Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. R...Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. Results revealed that the contents of elements(e.g., Fe, Mn, Cu, Zn, V, Co) were high in samples 22V-TVG10 and 26V-TVG05 from the sites near the hydrothermal areas, and low in sample 22V-TVG14, which was collected far from the hydrothermal areas. The contents of Ca, Sr and Ba in the samples showed opposite trends. A positive correlation between the concentrations of metallic elements(Cu, Zn, Co, Ni, Pb, V) and Fe in the samples were observed. These results are consistent with chemical evolution of the dispersing hydrothermal plume.展开更多
Marine copepods, Acartia erythraea, were exposed separately to aqueous Cu and Ag media and to a Cu+Ag mixture in a series of experiments during which the metal body burden and partitioning in the exoskeleton and pola...Marine copepods, Acartia erythraea, were exposed separately to aqueous Cu and Ag media and to a Cu+Ag mixture in a series of experiments during which the metal body burden and partitioning in the exoskeleton and polar and nonpolar parts of the animal cells were measured and the uptake and effiux rate constants for Cu and Ag were calculated. The metal uptake and effiux rate constants were 1.04×10^3±1.00×10^2 L·g^-1·d^-1 and 9.28× 102+ 1.43×10-2 d^-1 for Cu and 1.60× 104+1.78×10^3L·g^-1·d^-1and 9.23×10^2 -4- 9.1 1×10^3d^-1 for Ag, respectively. For both Cu and Ag, the uptake rate constants when the copepods were exposed to solutions of a single metal were generally higher than that when the copepods were exposed to metal mixtures. The results suggest an antagonistic interaction between waterborne Cu and Ag exists in marine copepods. The different distributions of Cu and Ag among the exoskeleton and polar and nonpolar parts of the copepods revealed that the metal bioavailability in copepods exposed to metal mixtures enhanced in some degree compared to copepods exposed to single metal solutions.展开更多
Rainwater samples were collected in series in Qianliyan Island (southern Yellow Sea) and Shengsi Archipelago (East China Sea) between May 2000 and May 2002, chemical analysis for pH values, concentrations of heavy met...Rainwater samples were collected in series in Qianliyan Island (southern Yellow Sea) and Shengsi Archipelago (East China Sea) between May 2000 and May 2002, chemical analysis for pH values, concentrations of heavy metals (Cu, Pb, Zn and Cd) and nutrients (NH4+, NO3-, PO43-, SiO32-) were performed. Results indicate that concentrations of most of the heavy metals and nutrients in rainwater show clear seasonal variation, i.e. high level in winter and low level in summer. Regionally, concentrations are higher in the southern Yellow Sea than in the East China Sea, but the annual input of heavy metals into oceans by wet deposition is similar in both stations. However, the input of nutrients by wet deposition in the East China Sea is 2–3 times higher than that in the southern Yellow Sea. In individual, Pb and PO43- are input to the sea mainly by dry deposition; whereas Cu, Zn, Cd and N compounds are input dominantly by wet deposition, the N/P ratios in the rainwater from two stations are much higher than those in seawater, showing a significant impact of atmospheric wet deposition on marine production and biogeochemical circulation of nutrients in these sea regions.展开更多
China, Russia and India, three Eurasian BRICS countries, are close neighbors, geographically located in the Pacific Ocean, the Arctic Ocean and the Indian Ocean respectively. The research questions why these three cou...China, Russia and India, three Eurasian BRICS countries, are close neighbors, geographically located in the Pacific Ocean, the Arctic Ocean and the Indian Ocean respectively. The research questions why these three countries have some similar characteristics in their diplomacies and foreign policies, which differentiates them both from traditional developed countries and typical developing countries. Before the assessment of this question, analysis of culture and its characteristics, international strategies and diplomacies of these three BRICS countries is necessary and appropriate. Culture plays a special and crucial role in international politics or international relations. The unique cultures of Eurasian BRICS countries, China, Russia and India, have special influences on their diplomacies, which has created a new landscape in current world economy and politics.展开更多
The concentrations of heavy metals (As, Hg, Cr, Pb and Zn) were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable...The concentrations of heavy metals (As, Hg, Cr, Pb and Zn) were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg (0.17 ± 0.01 μg/g) and Cr (23.7 ± 4.15 μg/g) compared to other locations. Higher concentration of Hg (0.06 ±0.02 μg/g) was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr (45.5 ± 6.83 μg/g) was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO (Food and Agricultural Organization) in 1983 and they all were below permissible limits for human consumption.δ展开更多
The leaders of the Meiji Restoration believed in their master, Yoshida Shoin (吉田松陰), who claimed that in order for the islands of Japan not to be a colony of the powerful Western states, Japan had to conquer nea...The leaders of the Meiji Restoration believed in their master, Yoshida Shoin (吉田松陰), who claimed that in order for the islands of Japan not to be a colony of the powerful Western states, Japan had to conquer nearby countries. This led to Japan’s invasion of the Ryukyu Islands, Taiwan, Korea, and Manchuria, which ultimately led to the Manchurian Incident of 1931, the Sino-Japanese War, and the Pacific War. Surprisingly, the subject and the timing of each and every one of these acts of war were in the same order of Yoshida Shoin’s proposal on preoccupancy. The Sino-Japanese war of 1894 was romanticized as clearing the barbaric culture by civilization, and the Russo-Japanese war of 1904 was romanticized as the realization of Eastern Peace. However, Japanese policies of aggressions were first deemed illegal by international law during the 1931 Manchurian Incident by the investigations of the League of Nations. The Japanese Empire received the recommendation by the League of Nations to restore to original state, but declined and exited from the League of Nations. Following their exit, they started the Sino-Japanese War and the Pacific War and eventually lost in 1945. The goal of the San Francisco Peace Treaty of 1951 was to punish Japan’s aggressions. However, as the Cold War between the East and the West started to arise in 1948, the punishment was eased, and their punishment for the aggressions on the Ryukyu Islands, Taiwan, and Korea was nearly unasked for. This paper examines the issues of the San Francisco Peace Treaty in the views of the international law of the League of Nations, established by Manley O. Hudson of Harvard University and others in U.S. academia and judiciary.展开更多
文摘The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.
基金supported by the Study on the Analysis of the Impacts of Reclamation Engineering on Marine Ecological Environment in Yangshan Deepwater Harbor and Protecting Measures of Shanghai Municipal Science and Technology Commission (No. 12231203402)
文摘Temporal and spatial variations of concentrations of heavy metals including mercury (Hg), zinc (Zn), lead (Pb), arsenic (As), copper (Cu), and cadmium (Cd) in the sediments of the Yangshan Deepwater Harbor were determined based on 6 cruises in autumn and winter, respectively, from 2010 to 2013. The results demonstrated that the overall concentrations of heavy metals were low and distributed in uniform patterns. The concentrations of Hg, Zn, Pb, and Cd in autumn were significantly higher than those in winter with small fluctuations for As and Cu in terms of seasonal variations. Results of factor analysis showed that Pb, Cd, and Zn were derived from inland industrial and shipping discharges as well as the degradation of organic pollutants in marine environment. While agricultural pollutions, cargo shifting and construction debris from reclamation projects contributed to the sources of Cu, As, and Hg. Ecological risk assessment by Mean Sediment Quality Guideline Quotient (SQG-Q) revealed that the degree for eco-risk of the sediments was low-and-moderate in autumn, higher than that in winter. Hg and Cu were the dominant eco-risk factors. The results of Index of geoaccumulation (Igeo) showed that the whole sites of the sea area were barely influenced by Hg, As, Zn, and Pb, and the extents of Cd and Cu contaminations were in low grade. Contamination degree of all the six heavy metals could be ranked as the following: Cd〉Pb〉Zn〉Hg〉As. According to the results of integrated score of factor analysis, the contamination degree for heavy metals in sediments of the Yangshan Deepwater Harbor was low, despite sites No.5, No.4 and No.3, which were heavily contaminated compared with others.
基金supported by the Fundamental Research Funds for the Central Universities of China (Grant No. 201022001)
文摘Delay-difference models are intermediate between simple surplus-production models and complicated age-structured models. Such intermediate models are more efficient and require less data than age-structured models. In this study, a delay-differ- ence model was applied to fit catch and catch per unit effort (CPUE) data (1975-2011) of the southern Atlantic albacore (Thunnus alalunga) stock. The proposed delay-difference model captures annual fluctuations in predicted CPUE data better than Fox model. In a Monte Carlo simulation, white noises (CVs) were superimposed on the observed CPUE data at four levels. Relative estimate error was then calculated to compare the estimated results with the true values of parameters a and fl in Ricker stock-recruitment model and the catchability coefficient q. a is more sensitive to CV than fl and q. We also calculated an 80% percentile confidence interval of the maximum sustainable yield (MSY, 21756 t to 23408 t; median 22490 t) with the delay-difference model. The yield of the southern Atlantic albacore stock in 2011 was 24122t, and the estimated ratios of catch against MSY for the past seven years were approxi- mately 1.0. We suggest that care should be taken to protect the albacore fishery in the southern Atlantic Ocean. The proposed de- lay-difference model provides a good fit to the data of southern Atlantic albacore stock and may be a useful choice for the assessment of regional albacore stock.
文摘Experiments were designed to expose the filter-feeding bivalve Perna viridis to different Cd-contaminated water environments in order to compare the different pathways through which Cd is accumulated. Results show that mussels can accumulate Cd through seawater, food, sediment and suspended particle pathways in a short period of time. Mussels' uptake of Cd through the seawater pathway reaches the highest concentration approximately 3 and 9 times larger than through the algae and sediment pathways respectively after 7 d. This indicates that the Cd-accumulation through seawater is most efficient. Results also indicate that the uptake directly through contaminated algae, particles or sediments ingested by mussels is less important when compared with the uptake of Cd by mussels through the seawater pathway. Metal uptake pathways and mechanisms of bioaccumulation by marine bivalve are also discussed in this paper.
文摘Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modem lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system.
基金Project(ISRO/RES/3/683/15-16 dt 07.08.2015)supported by Indian Space Research Organization
文摘Friction stir welding provides better retention of ductility and plasticity in comparison to fusion welding and it increases the stability against cracking.This study aims to enhance both the ductility and strength of the welded joints.Tool profile was found to play an important role in retaining ductility,understanding the metal flow behavior and determining the fracture initiating point.The microstructure of different regions in the onion ring was inferred to correlate the strength with the metal flow pattern.The onion ring pattern strengthened the weld nugget.Shoulder and taper threaded profile tool resulted in superior mechanical properties.Microhardness results confirmed that the fracture runs through low hardness areas such as heat affected zone and thermo-mechanically affected zone.The scanning electron microscopic images revealed elongated grains and dimples,justifying ductile mode of fracture.
文摘Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese longliners during 2003,2004 and 2005,which is a part of Chinese Tuna Fishery Scientific Observer Program(CTFSOP) . The reproductive biology has been investigated. A total of 1 023 samples are collected including 417 ovaries and 606 testes. Spawning activities of yellowfin tuna have been studied for both male and female from January to June. The data showed that the average monthly sex ratio is 0.59,and the minimum length at sexual maturity is 101 cm for female and 110 cm for male respectively. Length at 50% sexual maturity is esti-mated at 113.77 cm for female and 120.20 cm for male,whereas maturation rate is 0.066 cm-1 for female and 0.091 cm-1 for male. Sex ratio by length class indicates that the proportion of male is higher than female's along with size increasing;for instance,in the group of the body length longer than 145 cm,some females have their body length from 145 to 160 cm and males have their body length at 160 cm and even longer. Statistically,yellowfin tuna has a significant seasonal reproduction.
基金supported by the Marine Special Scientific Fund for the Non-profit Public Industry of China (200805031)Fund of Key Laboratory of Fishery Ecology and Environment, Guangdong Province (LFE-20144)Scientific Research Foundation for the Third Institute of Oceanography, State Oceanic Administration (No. 2013031)
文摘The distribution of hexachloroeyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in the surface sea- water and sediment of Jincheng Bay mariculture area were investigated in the present study. The concentration of total HCHs and DDTs ranged from 2.98 to 14.87ngL-l and were〈0.032ngL-1, respectively, in surface seawater, and ranged from 5.52 to 9.43 and from 4.11 to 6.72 ng g-l, respectively, in surface sediment. It was deduced from the composition profile of HCH isomers and DDT congeners that HCH residues derived from a mixture of technical-grade HCH and lindane whereas the DDT residues derived from technical-grade DDT and dicofol. Moreover, both HCH and DDT residues may mainly originate from historical inputs. The hazard quotient of α-HCH, β-HCH, γ-HCH and δ-HCH to marine species was 0.030, 0.157, 3.008 and 0.008, respectively. It was estimated that the overall probability of adverse biological effect from HCHs was less than 5%, indicating that its risk to seawater column spe- cies was low. The threshold effect concentration exceeding frequency of γ-HCH, p,p'-DDD, p,p'-DDE and p,p'-DDT in sediment ranged from 8.3% to 100%, and the relative concentration of the HCH and DDT mixture exceeded their probable effect level in sediment. These findings indicated that the risk to marine benthos was high and potentially detrimental to the safety of aquatic prod- ucts, e.g., sea cucumber and benthic shellfish.
文摘The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.
基金the National Natural Science Foundation of China (No. 41306053)the Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences (Nos. MGE 2015KG04 and MGE2015KG01)+2 种基金the Open Fund of the Key Laboratory of Submarine Geosciences, State Oceanic Administration, People’s Republic of China (No. KSLG 1503)the Special Fund for the Taishan Scholar Program of Shandong Province (No. ts201511061)The authors would like to thank the crews of the COMRA cruises (DY115-22 and DY115-26)
文摘Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. Results revealed that the contents of elements(e.g., Fe, Mn, Cu, Zn, V, Co) were high in samples 22V-TVG10 and 26V-TVG05 from the sites near the hydrothermal areas, and low in sample 22V-TVG14, which was collected far from the hydrothermal areas. The contents of Ca, Sr and Ba in the samples showed opposite trends. A positive correlation between the concentrations of metallic elements(Cu, Zn, Co, Ni, Pb, V) and Fe in the samples were observed. These results are consistent with chemical evolution of the dispersing hydrothermal plume.
文摘Marine copepods, Acartia erythraea, were exposed separately to aqueous Cu and Ag media and to a Cu+Ag mixture in a series of experiments during which the metal body burden and partitioning in the exoskeleton and polar and nonpolar parts of the animal cells were measured and the uptake and effiux rate constants for Cu and Ag were calculated. The metal uptake and effiux rate constants were 1.04×10^3±1.00×10^2 L·g^-1·d^-1 and 9.28× 102+ 1.43×10-2 d^-1 for Cu and 1.60× 104+1.78×10^3L·g^-1·d^-1and 9.23×10^2 -4- 9.1 1×10^3d^-1 for Ag, respectively. For both Cu and Ag, the uptake rate constants when the copepods were exposed to solutions of a single metal were generally higher than that when the copepods were exposed to metal mixtures. The results suggest an antagonistic interaction between waterborne Cu and Ag exists in marine copepods. The different distributions of Cu and Ag among the exoskeleton and polar and nonpolar parts of the copepods revealed that the metal bioavailability in copepods exposed to metal mixtures enhanced in some degree compared to copepods exposed to single metal solutions.
基金Supported by the National "973" Program (No. G1999043705), and the Natural Sciences Foundation of Shandong Province (No. Y2000E02).
文摘Rainwater samples were collected in series in Qianliyan Island (southern Yellow Sea) and Shengsi Archipelago (East China Sea) between May 2000 and May 2002, chemical analysis for pH values, concentrations of heavy metals (Cu, Pb, Zn and Cd) and nutrients (NH4+, NO3-, PO43-, SiO32-) were performed. Results indicate that concentrations of most of the heavy metals and nutrients in rainwater show clear seasonal variation, i.e. high level in winter and low level in summer. Regionally, concentrations are higher in the southern Yellow Sea than in the East China Sea, but the annual input of heavy metals into oceans by wet deposition is similar in both stations. However, the input of nutrients by wet deposition in the East China Sea is 2–3 times higher than that in the southern Yellow Sea. In individual, Pb and PO43- are input to the sea mainly by dry deposition; whereas Cu, Zn, Cd and N compounds are input dominantly by wet deposition, the N/P ratios in the rainwater from two stations are much higher than those in seawater, showing a significant impact of atmospheric wet deposition on marine production and biogeochemical circulation of nutrients in these sea regions.
文摘China, Russia and India, three Eurasian BRICS countries, are close neighbors, geographically located in the Pacific Ocean, the Arctic Ocean and the Indian Ocean respectively. The research questions why these three countries have some similar characteristics in their diplomacies and foreign policies, which differentiates them both from traditional developed countries and typical developing countries. Before the assessment of this question, analysis of culture and its characteristics, international strategies and diplomacies of these three BRICS countries is necessary and appropriate. Culture plays a special and crucial role in international politics or international relations. The unique cultures of Eurasian BRICS countries, China, Russia and India, have special influences on their diplomacies, which has created a new landscape in current world economy and politics.
文摘The concentrations of heavy metals (As, Hg, Cr, Pb and Zn) were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg (0.17 ± 0.01 μg/g) and Cr (23.7 ± 4.15 μg/g) compared to other locations. Higher concentration of Hg (0.06 ±0.02 μg/g) was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr (45.5 ± 6.83 μg/g) was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO (Food and Agricultural Organization) in 1983 and they all were below permissible limits for human consumption.δ
文摘The leaders of the Meiji Restoration believed in their master, Yoshida Shoin (吉田松陰), who claimed that in order for the islands of Japan not to be a colony of the powerful Western states, Japan had to conquer nearby countries. This led to Japan’s invasion of the Ryukyu Islands, Taiwan, Korea, and Manchuria, which ultimately led to the Manchurian Incident of 1931, the Sino-Japanese War, and the Pacific War. Surprisingly, the subject and the timing of each and every one of these acts of war were in the same order of Yoshida Shoin’s proposal on preoccupancy. The Sino-Japanese war of 1894 was romanticized as clearing the barbaric culture by civilization, and the Russo-Japanese war of 1904 was romanticized as the realization of Eastern Peace. However, Japanese policies of aggressions were first deemed illegal by international law during the 1931 Manchurian Incident by the investigations of the League of Nations. The Japanese Empire received the recommendation by the League of Nations to restore to original state, but declined and exited from the League of Nations. Following their exit, they started the Sino-Japanese War and the Pacific War and eventually lost in 1945. The goal of the San Francisco Peace Treaty of 1951 was to punish Japan’s aggressions. However, as the Cold War between the East and the West started to arise in 1948, the punishment was eased, and their punishment for the aggressions on the Ryukyu Islands, Taiwan, and Korea was nearly unasked for. This paper examines the issues of the San Francisco Peace Treaty in the views of the international law of the League of Nations, established by Manley O. Hudson of Harvard University and others in U.S. academia and judiciary.