2020 Vol. 42, No. 4
Display Method:
2020, 42(4): 1-11.
doi: 10.3969/j.issn.0253-4193.2020.04.001
Abstract:
The extracellular enzyme activity of seawater can indicate the distribution characteristics of organic and the nutritional status of microorganisms. Activities of eight extracellular enzymes, including alkaline phosphatase, lipase, leucine aminopeptidase, chitinase, cellulose, xylosidase, α-D-glucosidase and β-D-galactosidase, were measured in the surface seawaters collected from 44 stations of the Yellow Sea and the East China Sea from March 25 to April 15, 2017 and from 10 stations of the Jiaozhou Bay nearby waters from April 28 to 29, 2018. In the spring of 2017, the high-value areas of alkaline phosphatase and lipase appeared in the northern coast of Jiangsu and the middle of the Yellow Sea, alkaline phosphatase activity and phosphate concentration were positively correlated. High activity areas of the other six enzymes (leucine aminopeptidase, chitinase, cellulose, xylosidase, α-D-glucosidase and β-D-galactosidase) appeared in the open sea outside the east of the Changjiang River Estuary. The average activities of β-D-galactosidase and xylosidase were significantly higher in the East China Sea than in the Yellow Sea. The decreasing order of average enzyme activities of the eight enzymes was as follows: alkaline phosphatase, lipase, leucine aminopeptidase, chitinase, α-D-glucosidase, β-D-galactosidase, cellulose, xylosidase, the values of α-D-glucosidase and β-D-galactosidase are proximate. The activities of alkaline phosphates, lipase and xylosidase in the Jiaozhou Bay nearby waters in spring 2018 decreased from nearshore to far shore. The decreasing order of the average enzyme activity of the eight enzymes was as follows: alkaline phosphatase, lipase, leucine aminopeptidase, xylosidase, α-D-glucosidase, β-D-galactosidase, cellulose, chitinase, the values of cellulose and chitinase are proximate. The alkaline phosphatase and lipase activities in the Yellow Sea were significantly higher than those in the East China Sea and Jiaozhou Bay. The average enzymatic activities of polysaccharide hydrolases (chitinase, cellulose, α-D-glucosidase, β-D-galactosidase and xylosidase) were the lowest in the Yellow Sea compared with those in the East China Sea and Jiaozhou Bay nearby waters. Our results are beneficial to understand the degradation of organic carbon by plankton and heterotrophic bacteria and the distribution of marine organic carbon in the coastal water of China.
The extracellular enzyme activity of seawater can indicate the distribution characteristics of organic and the nutritional status of microorganisms. Activities of eight extracellular enzymes, including alkaline phosphatase, lipase, leucine aminopeptidase, chitinase, cellulose, xylosidase, α-D-glucosidase and β-D-galactosidase, were measured in the surface seawaters collected from 44 stations of the Yellow Sea and the East China Sea from March 25 to April 15, 2017 and from 10 stations of the Jiaozhou Bay nearby waters from April 28 to 29, 2018. In the spring of 2017, the high-value areas of alkaline phosphatase and lipase appeared in the northern coast of Jiangsu and the middle of the Yellow Sea, alkaline phosphatase activity and phosphate concentration were positively correlated. High activity areas of the other six enzymes (leucine aminopeptidase, chitinase, cellulose, xylosidase, α-D-glucosidase and β-D-galactosidase) appeared in the open sea outside the east of the Changjiang River Estuary. The average activities of β-D-galactosidase and xylosidase were significantly higher in the East China Sea than in the Yellow Sea. The decreasing order of average enzyme activities of the eight enzymes was as follows: alkaline phosphatase, lipase, leucine aminopeptidase, chitinase, α-D-glucosidase, β-D-galactosidase, cellulose, xylosidase, the values of α-D-glucosidase and β-D-galactosidase are proximate. The activities of alkaline phosphates, lipase and xylosidase in the Jiaozhou Bay nearby waters in spring 2018 decreased from nearshore to far shore. The decreasing order of the average enzyme activity of the eight enzymes was as follows: alkaline phosphatase, lipase, leucine aminopeptidase, xylosidase, α-D-glucosidase, β-D-galactosidase, cellulose, chitinase, the values of cellulose and chitinase are proximate. The alkaline phosphatase and lipase activities in the Yellow Sea were significantly higher than those in the East China Sea and Jiaozhou Bay. The average enzymatic activities of polysaccharide hydrolases (chitinase, cellulose, α-D-glucosidase, β-D-galactosidase and xylosidase) were the lowest in the Yellow Sea compared with those in the East China Sea and Jiaozhou Bay nearby waters. Our results are beneficial to understand the degradation of organic carbon by plankton and heterotrophic bacteria and the distribution of marine organic carbon in the coastal water of China.
2020, 42(4): 113-121.
doi: 10.3969/j.issn.0253-4193.2020.04.013
Abstract:
Micro plastics in sandy sediments collected from the intertidal zone of the offshore area of Qinhuangdao were floated by saturated NaCl solution and filtrated with membrane filter. Micro plastic particles were observed using microscope and infrared spectroscopy to discuss the origin and morphology. The surface morphology of micro plastics particles was characterized by scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) to analyze surface morphology and elements. The geo accumulation indexes (Igeo) and enrichment factors (EF) were used to study the pollution level and enrichment of heavy metals (Hg, Cd and Pb) in sandy sediments. Total organic carbon (TOC), total nitrogen (TN) and loss on ignition (LOI) and stable isotopes of carbon and nitrogen (δ13C and δ15N) in sandy sediments were determined in order to analyze the source characteristics. The results indicated that there were three types of micro plastics: fiber, foam and film. Fiber was in the majority of micro plastics. Micro plastic particles were enriched with Si, Al, Mg, Fe and Ca in the surface. Hg and Cd were seriously enriched, and Pb was not enriched in the sandy sediments. The concentrations of TOC and TN were low; TOC/TN ratio and stable isotopic composition of C and N (δ13C and δ15N) indicated that TOC originated from marine plankton algae.
Micro plastics in sandy sediments collected from the intertidal zone of the offshore area of Qinhuangdao were floated by saturated NaCl solution and filtrated with membrane filter. Micro plastic particles were observed using microscope and infrared spectroscopy to discuss the origin and morphology. The surface morphology of micro plastics particles was characterized by scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) to analyze surface morphology and elements. The geo accumulation indexes (Igeo) and enrichment factors (EF) were used to study the pollution level and enrichment of heavy metals (Hg, Cd and Pb) in sandy sediments. Total organic carbon (TOC), total nitrogen (TN) and loss on ignition (LOI) and stable isotopes of carbon and nitrogen (δ13C and δ15N) in sandy sediments were determined in order to analyze the source characteristics. The results indicated that there were three types of micro plastics: fiber, foam and film. Fiber was in the majority of micro plastics. Micro plastic particles were enriched with Si, Al, Mg, Fe and Ca in the surface. Hg and Cd were seriously enriched, and Pb was not enriched in the sandy sediments. The concentrations of TOC and TN were low; TOC/TN ratio and stable isotopic composition of C and N (δ13C and δ15N) indicated that TOC originated from marine plankton algae.
2020, 42(4): 122-127.
doi: 10.3969/j.issn.0253-4193.2020.04.014
Abstract:
In this study, the activity range and distribution patterns of radium and radon isotopes in the coast sea of the Hongyanhe Nuclear Power Plant were investigated in autumn, 2017. The water ages were calculated by "Apparent Radium Age Model", which distribution was then used to assess the major direction of water transport in the study area. We also discussed the relationship between jellyfish abundance distribution and water transport direction. The results indicate that: (1) the activity ranges of 224Ra, 226Ra and 222Rn were 2.9−62.4 dpm/(100 L), 11.9−57.4 dpm/(100 L), and 0.1−1.3 dpm/L in the study area in autumn, respectively. (2) Based on the “Apparent Radium Age Model”, the so-calculated water ages were ranged from 0 to 16 d, with an average of (10.9±3.6) d. The major water transport direction was towards northeast with the velocity of 7.2 cm/s. (3) There was clear correlation between the distribution of jellyfish abundance and the major water transport direction. The higher jellyfish abundance was found in main water transport direction with older water ages.
In this study, the activity range and distribution patterns of radium and radon isotopes in the coast sea of the Hongyanhe Nuclear Power Plant were investigated in autumn, 2017. The water ages were calculated by "Apparent Radium Age Model", which distribution was then used to assess the major direction of water transport in the study area. We also discussed the relationship between jellyfish abundance distribution and water transport direction. The results indicate that: (1) the activity ranges of 224Ra, 226Ra and 222Rn were 2.9−62.4 dpm/(100 L), 11.9−57.4 dpm/(100 L), and 0.1−1.3 dpm/L in the study area in autumn, respectively. (2) Based on the “Apparent Radium Age Model”, the so-calculated water ages were ranged from 0 to 16 d, with an average of (10.9±3.6) d. The major water transport direction was towards northeast with the velocity of 7.2 cm/s. (3) There was clear correlation between the distribution of jellyfish abundance and the major water transport direction. The higher jellyfish abundance was found in main water transport direction with older water ages.
2020, 42(4): 12-19.
doi: 10.3969/j.issn.0253-4193.2020.04.002
Abstract:
This study investigated the oxidative stress and energy utilization responses of juvenile cobia (Rachycentron canadum) to environmental hypoxia stress, and provided reference for the healthy cultivation of cobia. Through the hypoxia stress-reoxygenation test, the oxidative stress and energy utilization indexes of liver and muscle tissues were measured after hypoxia ((2.64±0.25)mg/L) stress for 3 h and reoxygenation ((6.34±0.15)mg/L) stress for 8 h, 24 h and 48 h. The results showed that after hypoxia stress, the activity of malondialdehyde (MDA), catalase (CAT) and glutathione reductase (GR) in the liver were significantly lower than that in the control group (p<0.05), and the activity of lactate dehydrogenase (LDH) was significantly higher than that in the control group (p<0.05). MDA and lipid peroxidase (LPO) activities in muscle were significantly lower than those in control group (p<0.05), and superoxide dismutase (SOD) and LDH activities were significantly higher than those in control group (p<0.05). The contents of muscle glycogen and liver glycogen were significantly lower than those of control group (p<0.01). During reoxygenation, the contents of MDA, LPO, SOD, CAT, glutathione peroxidase (GPx) and GR in liver and muscle all increased differentially. Liver glycogen content was significantly higher than that of the control group 24 h after reoxygenation (p<0.05), and significantly lower than that of the control group 48 h after reoxygenation (p<0.05). Muscle glycogen content was significantly lower than that of control group after reoxygenation for 8 h, 24 h and 48 h (p<0.05). In conclusion, hypoxia stress can cause some oxidative damage to the body of cobia, and the enzyme activity and energy supply of liver and muscle tissues change. The reoxygenation environment after hypoxia stress causes more severe oxidative damage to the body, which can be gradually restored to the normal level through physiological regulation.
This study investigated the oxidative stress and energy utilization responses of juvenile cobia (Rachycentron canadum) to environmental hypoxia stress, and provided reference for the healthy cultivation of cobia. Through the hypoxia stress-reoxygenation test, the oxidative stress and energy utilization indexes of liver and muscle tissues were measured after hypoxia ((2.64±0.25)mg/L) stress for 3 h and reoxygenation ((6.34±0.15)mg/L) stress for 8 h, 24 h and 48 h. The results showed that after hypoxia stress, the activity of malondialdehyde (MDA), catalase (CAT) and glutathione reductase (GR) in the liver were significantly lower than that in the control group (p<0.05), and the activity of lactate dehydrogenase (LDH) was significantly higher than that in the control group (p<0.05). MDA and lipid peroxidase (LPO) activities in muscle were significantly lower than those in control group (p<0.05), and superoxide dismutase (SOD) and LDH activities were significantly higher than those in control group (p<0.05). The contents of muscle glycogen and liver glycogen were significantly lower than those of control group (p<0.01). During reoxygenation, the contents of MDA, LPO, SOD, CAT, glutathione peroxidase (GPx) and GR in liver and muscle all increased differentially. Liver glycogen content was significantly higher than that of the control group 24 h after reoxygenation (p<0.05), and significantly lower than that of the control group 48 h after reoxygenation (p<0.05). Muscle glycogen content was significantly lower than that of control group after reoxygenation for 8 h, 24 h and 48 h (p<0.05). In conclusion, hypoxia stress can cause some oxidative damage to the body of cobia, and the enzyme activity and energy supply of liver and muscle tissues change. The reoxygenation environment after hypoxia stress causes more severe oxidative damage to the body, which can be gradually restored to the normal level through physiological regulation.
2020, 42(4): 20-28.
doi: 10.3969/j.issn.0253-4193.2020.04.003
Abstract:
As one of the most abundant species of family Notothenioidei, rock cod (Patagonotothen ramsayi) plays an important role in energy transfer in the food web in the Patagonian Shelf. Currently, the work on feeding ecology of this species mainly bases on the conventional stomach content analysis, which only reflects short-term variation in feeding. Therefore, this study analyzed the distribution of fatty acids in three tissues (muscle, liver and gonad) of rock cod, and analyzed whether fatty acids in these tissues can characterize their feeding habits and transfer of diet. The results indicate that 27 kinds of fatty acids were detected in the tissues of rock cod. The storage and use of fatty acids in liver and gonad tissues are not suitable for indicating the diet of rock cod because they are involved in growth and reproduction. Compared to liver and gonad tissues, the longer renewal cycle of muscle tissue may better reflect its absorption of fatty acids from food. For the analysis of fatty acids in the muscle tissue of the rock cod in different size groups, it is inferred that the small-size rock cod (immature individual, 100−240 mm) mainly fed on planktonic organisms. The benthic feeding characteristics of rock cod increase with the increasing of size, and the feeding pattern transfer from planktonic feeding to planktonic-benthic feeding. In addition, due to the consumption of a certain amount of fishery discards by rock cod, the contribution rate of saprophytic food chain to predatory food chain is weakened. The results derive from this study further demonstrate that, compare to tissues of liver and gonad, the fatty acids of muscle tissue can be more suitable to indicate the food source of oceanic fish species.
As one of the most abundant species of family Notothenioidei, rock cod (Patagonotothen ramsayi) plays an important role in energy transfer in the food web in the Patagonian Shelf. Currently, the work on feeding ecology of this species mainly bases on the conventional stomach content analysis, which only reflects short-term variation in feeding. Therefore, this study analyzed the distribution of fatty acids in three tissues (muscle, liver and gonad) of rock cod, and analyzed whether fatty acids in these tissues can characterize their feeding habits and transfer of diet. The results indicate that 27 kinds of fatty acids were detected in the tissues of rock cod. The storage and use of fatty acids in liver and gonad tissues are not suitable for indicating the diet of rock cod because they are involved in growth and reproduction. Compared to liver and gonad tissues, the longer renewal cycle of muscle tissue may better reflect its absorption of fatty acids from food. For the analysis of fatty acids in the muscle tissue of the rock cod in different size groups, it is inferred that the small-size rock cod (immature individual, 100−240 mm) mainly fed on planktonic organisms. The benthic feeding characteristics of rock cod increase with the increasing of size, and the feeding pattern transfer from planktonic feeding to planktonic-benthic feeding. In addition, due to the consumption of a certain amount of fishery discards by rock cod, the contribution rate of saprophytic food chain to predatory food chain is weakened. The results derive from this study further demonstrate that, compare to tissues of liver and gonad, the fatty acids of muscle tissue can be more suitable to indicate the food source of oceanic fish species.
Population structure and spatial distribution of Cleisthenes herzensteini in Shandong coastal waters
2020, 42(4): 29-39.
doi: 10.3969/j.issn.0253-4193.2020.04.004
Abstract:
Based on the survey data from the bottom-trawl surveys in Shandong coastal waters in autumn (October 2016), winter (January 2017), spring (May 2017) and summer (August 2017), the seasonal variations of population structure and spatial distribution of Cleisthenes herzensteini were studied. The results showed that the average length of C. herzensteini was larger in autumn and winter, while the average mass was larger in summer and autumn. When the length is more than 15 cm, the seasonal variation of mass is larger, and the growth rate of mass is the biggest in summer. The ages of C. herzensteini ranged from 1 to 5 years old, in which individuals of 1 and 2 years old accounted for 45.15% and 40.23% of the population, respectively. The parameters of the von Bertalanffy growth equation, L∞, K and t0, were 37.85 cm, 0.28 and −0.57, respectively. The Pauly empirical formula evaluated the natural mortality to be 0.54. The total mortality, the fishing mortality, the exploitation ratio, the age of first capture and the length of first capture were 1.69, 1.15, 68.05%, 1.48 years old and 12.68 cm, respectively. In each season, only the ratio of male to female in summer was significantly different from that in 1:1 (p<0.05), and the number of females was significantly higher than that of males. 50% of the length of sexual maturity is 22.35 cm. The highest ratio of sexual maturity and the highest average coefficient of sexual maturity occur in summer. C. herzensteini mainly distributes in areas with bottom water temperature of 6.45−19.06℃, bottom salinity of 31.82−33.10 and depth of more than 50 m. Its average catch in autumn is much more than that in other seasons, which declines sharply in winter and then rises slowly. The C. herzensteini in Shandong coastal waters showed some phenomena, such as narrow length distribution, deterioration of food supply, delayed spawning period and over-exploited stock. The resources changed dramatically before and after the forbidden fishing period.
Based on the survey data from the bottom-trawl surveys in Shandong coastal waters in autumn (October 2016), winter (January 2017), spring (May 2017) and summer (August 2017), the seasonal variations of population structure and spatial distribution of Cleisthenes herzensteini were studied. The results showed that the average length of C. herzensteini was larger in autumn and winter, while the average mass was larger in summer and autumn. When the length is more than 15 cm, the seasonal variation of mass is larger, and the growth rate of mass is the biggest in summer. The ages of C. herzensteini ranged from 1 to 5 years old, in which individuals of 1 and 2 years old accounted for 45.15% and 40.23% of the population, respectively. The parameters of the von Bertalanffy growth equation, L∞, K and t0, were 37.85 cm, 0.28 and −0.57, respectively. The Pauly empirical formula evaluated the natural mortality to be 0.54. The total mortality, the fishing mortality, the exploitation ratio, the age of first capture and the length of first capture were 1.69, 1.15, 68.05%, 1.48 years old and 12.68 cm, respectively. In each season, only the ratio of male to female in summer was significantly different from that in 1:1 (p<0.05), and the number of females was significantly higher than that of males. 50% of the length of sexual maturity is 22.35 cm. The highest ratio of sexual maturity and the highest average coefficient of sexual maturity occur in summer. C. herzensteini mainly distributes in areas with bottom water temperature of 6.45−19.06℃, bottom salinity of 31.82−33.10 and depth of more than 50 m. Its average catch in autumn is much more than that in other seasons, which declines sharply in winter and then rises slowly. The C. herzensteini in Shandong coastal waters showed some phenomena, such as narrow length distribution, deterioration of food supply, delayed spawning period and over-exploited stock. The resources changed dramatically before and after the forbidden fishing period.
2020, 42(4): 40-46.
doi: 10.3969/j.issn.0253-4193.2020.04.005
Abstract:
Neon flying squid Ommastrephes bartramii is a short-lived cephalopod species whose abundance is highly susceptible to marine environmental changes and has large interannual fluctuations. Based on the statistical data from the squid fishery in the Northwest Pacific from 1995 to 2017, catch per unit effort (CPUE) was derived as an abundance index and the grey catastrophic prediction method was used to establish the GM（1, 1）model for the upper and lower catastrophic years and to forecast the future catastrophic years. The results show that the average relative error of the lower limit catastrophic prediction model established based on GLM-model-standardized CPUE is 15.32%, the average relative error of the upper catastrophic prediction model is 8.19%, and the accuracy tests for both models attain the level I accuracy. The study forecasts that the next upper catastrophic year may occur in 2021 (CPUE≥2.39 t/(ship·a)), and the lower catastrophe year occurred in 2027 (CPUE≤2.13 t/(ship·a)). The study also suggests that the Pacific Decadal Oscillation and El Niño-La Nina events are important factors driving large fluctuations in the squid abundance. The forecast can provide a reference for squid fishing enterprises and managing departments in the Northwest Pacific.
Neon flying squid Ommastrephes bartramii is a short-lived cephalopod species whose abundance is highly susceptible to marine environmental changes and has large interannual fluctuations. Based on the statistical data from the squid fishery in the Northwest Pacific from 1995 to 2017, catch per unit effort (CPUE) was derived as an abundance index and the grey catastrophic prediction method was used to establish the GM（1, 1）model for the upper and lower catastrophic years and to forecast the future catastrophic years. The results show that the average relative error of the lower limit catastrophic prediction model established based on GLM-model-standardized CPUE is 15.32%, the average relative error of the upper catastrophic prediction model is 8.19%, and the accuracy tests for both models attain the level I accuracy. The study forecasts that the next upper catastrophic year may occur in 2021 (CPUE≥2.39 t/(ship·a)), and the lower catastrophe year occurred in 2027 (CPUE≤2.13 t/(ship·a)). The study also suggests that the Pacific Decadal Oscillation and El Niño-La Nina events are important factors driving large fluctuations in the squid abundance. The forecast can provide a reference for squid fishing enterprises and managing departments in the Northwest Pacific.
2020, 42(4): 47-54.
doi: 10.3969/j.issn.0253-4193.2020.04.006
Abstract:
Research on the structure and complexity of food webs helps to analyze the function, nutrient dynamics and energy conversion of food webs. Based on the survey data of fishery resources and the analysis of gastric contents in five voyages in Haizhou Bay and its adjacent waters from March to December 2011, this study constructed a Haizhou Bay topology network based on 11 topological network indices. To study the structure and complexity of the Haizhou Bay food network. The results showed that the number of species in the Haizhou Bay food network (S) was 93, the number of connections (L) was 1 021, the number of interactions per species (L/S) was 10.98, the number of connections (L/S2) was 0.12; the proportions of top species, intermediate species, foundation species were 29%, 69% and 2%, respectively; the omnivorous index of food web was 87%; the connection complexity index SC was 22.2; the characteristic path length ChPath was 2.11, and the clustering coefficient CC was 0.23. Studies on the number of interactions and the number of connections in each species showed that the values of L/S and L/S2 were within the normal range, so the complexity of the Haizhou Bay food web remained high. Through the analysis of the structure of the food web by species ratio, omnivorous index, connection complexity index, characteristic path length and clustering coefficient, it was found that the food network structure of Haizhou Bay was in a stable state, and the proportion of basic species was low because the phytoplankton and seaweed groups were not classified. Through the study of the structure and complexity of Haizhou Bay food network, it provides an important basis for the in-depth study of the function of Haizhou Bay food network and the scientific management of Haizhou Bay fishery resources.
Research on the structure and complexity of food webs helps to analyze the function, nutrient dynamics and energy conversion of food webs. Based on the survey data of fishery resources and the analysis of gastric contents in five voyages in Haizhou Bay and its adjacent waters from March to December 2011, this study constructed a Haizhou Bay topology network based on 11 topological network indices. To study the structure and complexity of the Haizhou Bay food network. The results showed that the number of species in the Haizhou Bay food network (S) was 93, the number of connections (L) was 1 021, the number of interactions per species (L/S) was 10.98, the number of connections (L/S2) was 0.12; the proportions of top species, intermediate species, foundation species were 29%, 69% and 2%, respectively; the omnivorous index of food web was 87%; the connection complexity index SC was 22.2; the characteristic path length ChPath was 2.11, and the clustering coefficient CC was 0.23. Studies on the number of interactions and the number of connections in each species showed that the values of L/S and L/S2 were within the normal range, so the complexity of the Haizhou Bay food web remained high. Through the analysis of the structure of the food web by species ratio, omnivorous index, connection complexity index, characteristic path length and clustering coefficient, it was found that the food network structure of Haizhou Bay was in a stable state, and the proportion of basic species was low because the phytoplankton and seaweed groups were not classified. Through the study of the structure and complexity of Haizhou Bay food network, it provides an important basis for the in-depth study of the function of Haizhou Bay food network and the scientific management of Haizhou Bay fishery resources.
2020, 42(4): 55-65.
doi: 10.3969/j.issn.0253-4193.2020.04.007
Abstract:
In order to assess the health status of ecosystem on the Changjiang River Estuary waters, the ichthyoplankton is used to be indicators. Selecting 10 evaluation indices, which are the total number of ichthyoplankton species, number of benthic species, number of column species, number of intolerant species, proportion of tolerant species, proportion of omnivores, proportion of insectivorous, proportion of carnivores, number of individuals in each sample, proportion of hybrid. This study calculates the estuarine biotic integrity index (EBI) value of the 1986, 1999, 2007 and 2016 by using 1, 3, and 5 approximation of value assignment, and assesses the change trend of the ecosystem health in the Changjiang River Estuary water in recent 30 years. The results show that in 1986, 1999, 2007 and 2016, the EBI values were 52, 40, 36 and 34, respectively, and the corresponding EBI levels were “good”, “fair”, “fair-poor” and “poor”, respectively. By analyzing the results of EBI annual changes, it was found that the health status of ecosystem in the Changjiang River Estuary in recent 30 years showed a trend of declining first and then maintaining at a low level, indicating that the ecosystem of the Changjiang River Estuary waters is urgent to carry out timely protection and restoration.
In order to assess the health status of ecosystem on the Changjiang River Estuary waters, the ichthyoplankton is used to be indicators. Selecting 10 evaluation indices, which are the total number of ichthyoplankton species, number of benthic species, number of column species, number of intolerant species, proportion of tolerant species, proportion of omnivores, proportion of insectivorous, proportion of carnivores, number of individuals in each sample, proportion of hybrid. This study calculates the estuarine biotic integrity index (EBI) value of the 1986, 1999, 2007 and 2016 by using 1, 3, and 5 approximation of value assignment, and assesses the change trend of the ecosystem health in the Changjiang River Estuary water in recent 30 years. The results show that in 1986, 1999, 2007 and 2016, the EBI values were 52, 40, 36 and 34, respectively, and the corresponding EBI levels were “good”, “fair”, “fair-poor” and “poor”, respectively. By analyzing the results of EBI annual changes, it was found that the health status of ecosystem in the Changjiang River Estuary in recent 30 years showed a trend of declining first and then maintaining at a low level, indicating that the ecosystem of the Changjiang River Estuary waters is urgent to carry out timely protection and restoration.
2020, 42(4): 66-78.
doi: 10.3969/j.issn.0253-4193.2020.04.008
Abstract:
The full-length cDNA of glutathione S-transferase (Sc-GSTσ) and heat shock protein 90 (Sc-HSP90) genes were cloned from Sinonovacula constricta and their expression characteristics under ammonia nitrogen stress were analyzed. The results show that the full-length cDNA of Sc-GSTσ was 1 414 bp, and containing 639 bp open reading frame (ORF), encoding 212 amino acid polypeptides. The homology of amino acid sequence of Sc-GSTσ with other species’ GST amino acid sequence was 31.88%−43.40%. The full-length cDNA of Sc-HSP90 was 2 752 bp, ORF was 2 181 bp, encoding 726 amino acids. The amino acid sequence was 76.77%−87.05% homology with other species. Quantitative analysis showed that Sc-GSTσ and Sc-HSP90 genes were expressed in all tested tissues, the strongest expression being in the digestive gland. After exposure to ammonia, the mRNA expression of Sc-GSTσ and Sc-HSP90 were significantly up-regulated (p<0.05) in the digestive gland, indicating that ammonia stress induced stress response, both GST and HSP90 may be participate the process of detoxification or defense. However, the decrease of expression in the later period of stress is presumed to be due to the organism have limited ability to defense, which is not enough to protect the host from stress-induced cell damage.
The full-length cDNA of glutathione S-transferase (Sc-GSTσ) and heat shock protein 90 (Sc-HSP90) genes were cloned from Sinonovacula constricta and their expression characteristics under ammonia nitrogen stress were analyzed. The results show that the full-length cDNA of Sc-GSTσ was 1 414 bp, and containing 639 bp open reading frame (ORF), encoding 212 amino acid polypeptides. The homology of amino acid sequence of Sc-GSTσ with other species’ GST amino acid sequence was 31.88%−43.40%. The full-length cDNA of Sc-HSP90 was 2 752 bp, ORF was 2 181 bp, encoding 726 amino acids. The amino acid sequence was 76.77%−87.05% homology with other species. Quantitative analysis showed that Sc-GSTσ and Sc-HSP90 genes were expressed in all tested tissues, the strongest expression being in the digestive gland. After exposure to ammonia, the mRNA expression of Sc-GSTσ and Sc-HSP90 were significantly up-regulated (p<0.05) in the digestive gland, indicating that ammonia stress induced stress response, both GST and HSP90 may be participate the process of detoxification or defense. However, the decrease of expression in the later period of stress is presumed to be due to the organism have limited ability to defense, which is not enough to protect the host from stress-induced cell damage.
2020, 42(4): 79-86.
doi: 10.3969/j.issn.0253-4193.2020.04.009
Abstract:
Some so-called circumglobal and/or circumpolar marine species are proved to be complexes of cryptic species with restricted distributions by molecular analyses. These phenomena imply that marine species diversity has been underestimated. In this study we use shell morphological characteristics together with mitochondrial COI and 16S rRNA gene sequences in order to study the taxonomy and to identify species of genera Cavolinia and Diacavolinia in family Cavoliniidae from the Indian Ocean and Northwest Pacific Ocean. Our results showed that the species delimitation of Diacavolinia is not supported by molecular analyses, those morphospecies (D. grayi, D. vanutrechti, D. pacifica, D. elegans, D. angulosa, etc.) with distinct morphology from northwestern Pacific are a single species, namely D. longirostris. The subdivision of subspecies and/or forms for C. uncinata could not be confirmed by DNA evidence. Phylogenetic analysis of COI revealed two independent geographical lineages for C. uncinata, C. globulosa and D. longirostris respectively, suggesting that these morphspecies may harbour cryptic diversity. Nuclear mitochondrial pseudogene sequences of COI were detected from most individuals of D. longirostris, which can affect the analysis of DNA barcoding.
Some so-called circumglobal and/or circumpolar marine species are proved to be complexes of cryptic species with restricted distributions by molecular analyses. These phenomena imply that marine species diversity has been underestimated. In this study we use shell morphological characteristics together with mitochondrial COI and 16S rRNA gene sequences in order to study the taxonomy and to identify species of genera Cavolinia and Diacavolinia in family Cavoliniidae from the Indian Ocean and Northwest Pacific Ocean. Our results showed that the species delimitation of Diacavolinia is not supported by molecular analyses, those morphospecies (D. grayi, D. vanutrechti, D. pacifica, D. elegans, D. angulosa, etc.) with distinct morphology from northwestern Pacific are a single species, namely D. longirostris. The subdivision of subspecies and/or forms for C. uncinata could not be confirmed by DNA evidence. Phylogenetic analysis of COI revealed two independent geographical lineages for C. uncinata, C. globulosa and D. longirostris respectively, suggesting that these morphspecies may harbour cryptic diversity. Nuclear mitochondrial pseudogene sequences of COI were detected from most individuals of D. longirostris, which can affect the analysis of DNA barcoding.
2020, 42(4): 87-95.
doi: 10.3969/j.issn.0253-4193.2020.04.010
Abstract:
Sexual reproduction of hermatypic corals for coral reef restoration has become a hot topic in recent years. In May 2018, the samples of Favia favus and Platygyra carnosus were collected from the water of Weizhou Island, Guangxi. All of them were cultured in laboratory and the fertilized eggs were collected. The early development process of embryos and larvae was observed and recorded. The results showed that F.favus and P.carnosus were both hermaphrodites, in vitro fertilization, and began to spawn on the fifth to eighth day after the full moon; the early development of embryos and larvae experienced the cleavage stage, blastula stage, gastrula stage and planula stage; the oocytes of two corals did not have zooxanthella as they were ejected. This study records the sexual reproduction behavior of reef-building corals in Weizhou Island, and provides a theory when using sexual reproduction for coral ecological restoration in the future.
Sexual reproduction of hermatypic corals for coral reef restoration has become a hot topic in recent years. In May 2018, the samples of Favia favus and Platygyra carnosus were collected from the water of Weizhou Island, Guangxi. All of them were cultured in laboratory and the fertilized eggs were collected. The early development process of embryos and larvae was observed and recorded. The results showed that F.favus and P.carnosus were both hermaphrodites, in vitro fertilization, and began to spawn on the fifth to eighth day after the full moon; the early development of embryos and larvae experienced the cleavage stage, blastula stage, gastrula stage and planula stage; the oocytes of two corals did not have zooxanthella as they were ejected. This study records the sexual reproduction behavior of reef-building corals in Weizhou Island, and provides a theory when using sexual reproduction for coral ecological restoration in the future.
2020, 42(4): 96-103.
doi: 10.3969/j.issn.0253-4193.2020.04.011
Abstract:
Ocean acidification and warming are occurring globally through increasing CO2 absorption into the oceans, and impose two serious and imminent threats to the persistence of scleractinian corals and the reef ecosystem they construct. To evaluate the effects of ocean acidification and warming on the early life stages of the reef-building corals Acropora austera and A. intermedia, their larvae were incubated at a full cross design of two temperatures (about 28℃, about 30℃) and pCO2 (about 570 μatm, about 1 300 μatm) for 8 d. There were no significant differences in rates of settlement. Larval mortality rates of two reef-building corals were unaffected in any treatments. High pCO2 significantly reduced post-settlement survival of A. austera but not A. intermedia, with a 25.87% reduction in post-settlement survival in high pCO2 compared to control. Our results show that larvae settlement and mortality rates of the reef-building corals A. austera and A. intermedia were unaffected by ocean acidification and warming, and high pCO2 are more detrimental to mortality rates of juvenile A. austera than high temperature. Different species of juvenile corals exhibit species-specific response to ocean acidification and warming, with important implications for coral recruitment and even species structure composition of reef-building corals in the future ocean.
Ocean acidification and warming are occurring globally through increasing CO2 absorption into the oceans, and impose two serious and imminent threats to the persistence of scleractinian corals and the reef ecosystem they construct. To evaluate the effects of ocean acidification and warming on the early life stages of the reef-building corals Acropora austera and A. intermedia, their larvae were incubated at a full cross design of two temperatures (about 28℃, about 30℃) and pCO2 (about 570 μatm, about 1 300 μatm) for 8 d. There were no significant differences in rates of settlement. Larval mortality rates of two reef-building corals were unaffected in any treatments. High pCO2 significantly reduced post-settlement survival of A. austera but not A. intermedia, with a 25.87% reduction in post-settlement survival in high pCO2 compared to control. Our results show that larvae settlement and mortality rates of the reef-building corals A. austera and A. intermedia were unaffected by ocean acidification and warming, and high pCO2 are more detrimental to mortality rates of juvenile A. austera than high temperature. Different species of juvenile corals exhibit species-specific response to ocean acidification and warming, with important implications for coral recruitment and even species structure composition of reef-building corals in the future ocean.
2020, 42(4): 128-136.
doi: 10.3969/j.issn.0253-4193.2020.04.015
Abstract:
Based on the data from the zooplankton survey in the waters around the Ningde nuclear power plant in January (winter), April (spring), July (summer) and November (autumn) 2018, the structure and seasonal changes of jellyfish communities in the area were analyzed. The potential risks of jellyfish to the safe production of nuclear power in Ningde were discussed. The results showed that there were seasonal changes in the species composition, abundance distribution and dominant species succession of jellyfish in the Ningde nuclear power plant area. The numbers of jellyfish species in the spring, summer, autumn and winter were 7, 16, 9 and 3, respectively. The mean abundances were (45.48±8.24) ind./m3, (50.26±12.13) ind./m3, (3.68±1.91) ind./m3, and (0.18±0.07) ind./m3, respectively. The main dominant species were Laodicea indica, Pleurobrachia globosa, Diphyes chamissonis and Euphysa aurata. The seasonal succession of dominant species was obvious. The correlation analysis between the change of jellyfish abundance and environmental factors showed that the abundance of jellyfish in spring and summer was significantly related to the total abundance of zooplankton, and its number was significantly related to the number of copepods in zooplankton in summer（p<0.05, R=0.363). The abundance of jellyfish communities in autumn and winter was mainly affected by salinity. The salinity of the sea area was relatively low in autumn and winter, and the temperature is also low, so the abundance of jellyfish was also low. According to the distribution characteristics of jellyfish in Ningde, the jellyfish abundance of 50 ind./m3 was considered as the risk threshold value, and summer was the potentially high-risk season for ecological disasters. It was necessary to focus on the 5−20 km away from the intake area in summer; followed by the spring, the focus was on the 2.5−5 km away from the intake area; in autumn and winter, the safety of nuclear power sources was basically not caused by jellyfish.
Based on the data from the zooplankton survey in the waters around the Ningde nuclear power plant in January (winter), April (spring), July (summer) and November (autumn) 2018, the structure and seasonal changes of jellyfish communities in the area were analyzed. The potential risks of jellyfish to the safe production of nuclear power in Ningde were discussed. The results showed that there were seasonal changes in the species composition, abundance distribution and dominant species succession of jellyfish in the Ningde nuclear power plant area. The numbers of jellyfish species in the spring, summer, autumn and winter were 7, 16, 9 and 3, respectively. The mean abundances were (45.48±8.24) ind./m3, (50.26±12.13) ind./m3, (3.68±1.91) ind./m3, and (0.18±0.07) ind./m3, respectively. The main dominant species were Laodicea indica, Pleurobrachia globosa, Diphyes chamissonis and Euphysa aurata. The seasonal succession of dominant species was obvious. The correlation analysis between the change of jellyfish abundance and environmental factors showed that the abundance of jellyfish in spring and summer was significantly related to the total abundance of zooplankton, and its number was significantly related to the number of copepods in zooplankton in summer（p<0.05, R=0.363). The abundance of jellyfish communities in autumn and winter was mainly affected by salinity. The salinity of the sea area was relatively low in autumn and winter, and the temperature is also low, so the abundance of jellyfish was also low. According to the distribution characteristics of jellyfish in Ningde, the jellyfish abundance of 50 ind./m3 was considered as the risk threshold value, and summer was the potentially high-risk season for ecological disasters. It was necessary to focus on the 5−20 km away from the intake area in summer; followed by the spring, the focus was on the 2.5−5 km away from the intake area; in autumn and winter, the safety of nuclear power sources was basically not caused by jellyfish.
2020, 42(4): 104-112.
doi: 10.3969/j.issn.0253-4193.2020.04.012
Abstract:
In this study, we first used the spectral vegetation indices such as normalized difference vegetation index (NDVI), normalized difference water index (NDWI), atmospheric impedance vegetation index (ARPI) and visible spectrum slope ratio of coastal zone imager (CVSSR) to reconstruct the HY-1C coastal zone imager (CZI) image data of the Shankou mangrove national ecosystem nature reserve in Guangxi. And then, the minimum noise fraction rotation (MNF) was used to enhance the spectral difference between mangroves and general terrestrial vegetation on the reconstructed multi-band data set. We established a decision tree based on the MNF components to achieve automatic extracting mangrove information. The results show that the spectral indices reconstruction data and its MNF transformation can effectively enhance the difference between the mangroves and the general terrestrial vegetation on CZI images, the mangrove information can be effectively extracted by our decision tree. Compared with the experts’ interpretation results, the extracted accuracy of area of our method is over 90%. The overall detection accuracy is 88% after verification by random sample points.
In this study, we first used the spectral vegetation indices such as normalized difference vegetation index (NDVI), normalized difference water index (NDWI), atmospheric impedance vegetation index (ARPI) and visible spectrum slope ratio of coastal zone imager (CVSSR) to reconstruct the HY-1C coastal zone imager (CZI) image data of the Shankou mangrove national ecosystem nature reserve in Guangxi. And then, the minimum noise fraction rotation (MNF) was used to enhance the spectral difference between mangroves and general terrestrial vegetation on the reconstructed multi-band data set. We established a decision tree based on the MNF components to achieve automatic extracting mangrove information. The results show that the spectral indices reconstruction data and its MNF transformation can effectively enhance the difference between the mangroves and the general terrestrial vegetation on CZI images, the mangrove information can be effectively extracted by our decision tree. Compared with the experts’ interpretation results, the extracted accuracy of area of our method is over 90%. The overall detection accuracy is 88% after verification by random sample points.
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