2022 Vol. 44, No. 2
Display Method:
2022, 44(2): 123-131.
doi: 10.12284/hyxb2022038
Abstract:
Marine mesoscale eddies play an important role in plankton distribution, energy and salt transport. The automatic detection of marine mesoscale eddies is a basis for monitoring and analyzing their spatiotemporal variations. Traditional physical characteristics-based methods depend on artificially designing parameters, and result in low accuracy of mesoscale eddy extraction. Therefore, a marine mesoscale eddy automatic detection model based on improved U-Net network according to the marine satellite sea surface height images is proposed in this paper. The proposed model embeds the convolution attention modules in the feature extraction stage, which enables the model focuses on the most relevent area. Meanwhile, the model introduces the residual learning module to solve the problem that the network is too deep to train the model. In this paper, the satellite sea surface height dataset in the South Atlantic Ocean is taken as an example to carry out experiments. The results show that the proposed model achieves a high accuracy of 93.28% when detecting the marine mesoscale eddies, which is significantly better than EddyNet and other models. The model can provide a reliable technology for oceanographers to detect marine mesoscale eddies through the satellite sea surface height.
Marine mesoscale eddies play an important role in plankton distribution, energy and salt transport. The automatic detection of marine mesoscale eddies is a basis for monitoring and analyzing their spatiotemporal variations. Traditional physical characteristics-based methods depend on artificially designing parameters, and result in low accuracy of mesoscale eddy extraction. Therefore, a marine mesoscale eddy automatic detection model based on improved U-Net network according to the marine satellite sea surface height images is proposed in this paper. The proposed model embeds the convolution attention modules in the feature extraction stage, which enables the model focuses on the most relevent area. Meanwhile, the model introduces the residual learning module to solve the problem that the network is too deep to train the model. In this paper, the satellite sea surface height dataset in the South Atlantic Ocean is taken as an example to carry out experiments. The results show that the proposed model achieves a high accuracy of 93.28% when detecting the marine mesoscale eddies, which is significantly better than EddyNet and other models. The model can provide a reliable technology for oceanographers to detect marine mesoscale eddies through the satellite sea surface height.
2022, 44(2): 132-142.
doi: 10.12284/hyxb2022026
Abstract:
Cage aquaculture is one of the most important types of mariculture. The spectral characteristics of offshore cage aquaculture are greatly affected by the coastal vegetation and water body, so it is easy to cause noise problems. The new type of deep-sea cage aquaculture target is far from the shore, but the sea surface frame part of the aquaculture target is small, which has high spectral similarity with the natural water, and is difficult to extract. In this paper, deep edge spectral U-Net (DES-Unet) model is proposed to extract aquaculture information of two types of cage aquaculture. In this model, Canny operator bilateral filtering algorithm is used to remove the redundant spectral information after band operation, and the edge spectral features are extracted. The U-Net jump connection structure is used to fuse the edge spectral features with the deep convolution network features, and the pixel by pixel classification of softmax is used to extract the cage aquaculture information. Taking the offshore cage aquaculture and deep-sea cage aquaculture in Hainan Island as the research objects, the aquaculture information is extracted. The experimental results show that the accuracy of the proposed method is 97.35% on the offshore cage target and 98.99% on the deep-sea cage target. The result is better than the classical unsupervised algorithms and traditional deep learning model.
Cage aquaculture is one of the most important types of mariculture. The spectral characteristics of offshore cage aquaculture are greatly affected by the coastal vegetation and water body, so it is easy to cause noise problems. The new type of deep-sea cage aquaculture target is far from the shore, but the sea surface frame part of the aquaculture target is small, which has high spectral similarity with the natural water, and is difficult to extract. In this paper, deep edge spectral U-Net (DES-Unet) model is proposed to extract aquaculture information of two types of cage aquaculture. In this model, Canny operator bilateral filtering algorithm is used to remove the redundant spectral information after band operation, and the edge spectral features are extracted. The U-Net jump connection structure is used to fuse the edge spectral features with the deep convolution network features, and the pixel by pixel classification of softmax is used to extract the cage aquaculture information. Taking the offshore cage aquaculture and deep-sea cage aquaculture in Hainan Island as the research objects, the aquaculture information is extracted. The experimental results show that the accuracy of the proposed method is 97.35% on the offshore cage target and 98.99% on the deep-sea cage target. The result is better than the classical unsupervised algorithms and traditional deep learning model.
2022, 44(2): 1-10.
doi: 10.12284/hyxb2022040
Abstract:
In this study, we used stable isotope technology to analyze different species (fish, crustaceans, cephalopods, benthos, etc.) collected in spring, summer and autumn in the coastal waters of Jiangsu Province. We used SIBER model to calculate the trophic niche of consumers, and calculated the quantitative indicators of six metrics in different seasons. The results showed that there were no significant differences in δ13C and nitrogen δ15N values among three seasons (p>0.05). In spring, the δ13C values ranged from −24.47‰ to −14.50‰, the δ15N values ranged from 6.86‰ to (14.98±0.49)‰, and the trophic level ranged from 1.52 to 4.28±0.17. In summer, the δ13C values ranged from −19.86‰ to −14.44‰, the δ15N values ranged from 5.79‰ to (12.54±3.50)‰, and the trophic level ranged from 1.25 to 3.52. In autumn, the δ13C values ranged from (−22.17±4.90)‰ to (−14.21±0.36)‰, the δ15N values ranged from 6.30‰ to (14.60±0.51)‰, and the trophic level ranged from 1.34 to 4.15±0.14. The structure of food web was stable in each season, and the trophic niche of some species overlaps in different degrees. In addition, the food sources are more extensive, and the trophic level and community diversity are higher in spring, the food sources of consumers are more abundant, but the degree of trophic niche differentiation is lower in summer, while in autumn, the structure of food web is relatively simple, but the distribution of trophic niche is wider.
In this study, we used stable isotope technology to analyze different species (fish, crustaceans, cephalopods, benthos, etc.) collected in spring, summer and autumn in the coastal waters of Jiangsu Province. We used SIBER model to calculate the trophic niche of consumers, and calculated the quantitative indicators of six metrics in different seasons. The results showed that there were no significant differences in δ13C and nitrogen δ15N values among three seasons (p>0.05). In spring, the δ13C values ranged from −24.47‰ to −14.50‰, the δ15N values ranged from 6.86‰ to (14.98±0.49)‰, and the trophic level ranged from 1.52 to 4.28±0.17. In summer, the δ13C values ranged from −19.86‰ to −14.44‰, the δ15N values ranged from 5.79‰ to (12.54±3.50)‰, and the trophic level ranged from 1.25 to 3.52. In autumn, the δ13C values ranged from (−22.17±4.90)‰ to (−14.21±0.36)‰, the δ15N values ranged from 6.30‰ to (14.60±0.51)‰, and the trophic level ranged from 1.34 to 4.15±0.14. The structure of food web was stable in each season, and the trophic niche of some species overlaps in different degrees. In addition, the food sources are more extensive, and the trophic level and community diversity are higher in spring, the food sources of consumers are more abundant, but the degree of trophic niche differentiation is lower in summer, while in autumn, the structure of food web is relatively simple, but the distribution of trophic niche is wider.
2022, 44(2): 11-20.
doi: 10.12284/hyxb2022046
Abstract:
Corals are one of the carriers for recording information about changes in the marine environment. For example, determining U/Ca to reconstruction of sea water temperature or measure the Th/U isotopic ratio for dating to reconstruction sea level etc. However, measuring the U and Th contents and isotopic ratio of corals is a prerequisite for extracting the recorded marine environmental change information, the difficulty lies in the separation of Ca matrix and enrichment and purification of trace U and Th. Based on this, this study modified the pretreatment method of separation and purification U and Th with single column stage of UTEVA resin, and then combined with high resolution inductively coupled plasma mass spectrometry to determine U and Th contents of corals. The results demonstrate that the HNO3 medium concentration decrease from 3 mol/L to 2 mol/L will not affect the absorption efficiency of U and Th; 2 mL Milli-Q water can completely elute U, which significantly reduces the procedure blank value of the entire process of U; the improved method is used to determine the U and Th contents of three Hainan littoral corals (n=6, 1σ): U are (3.46±0.02)μg/g, (2.67±0.05)μg/g, (2.15±0.07)μg/g, respectively, Th are (10.12±0.24)ng/g, (4.82±0.10)ng/g, (5.65±0.12)ng/g, respectively; and the determination accuracy is below 3.3%, recovery rate of standard addition of U, Th are 97.9%–100.9%, 97.3%–99.7%, respectively. The method has high accuracy and good precision. This study provides a more accurate, convenient and rapid experimental method for the analysis of U and Th content and isotopic ratio in corals and other carbonate samples.
Corals are one of the carriers for recording information about changes in the marine environment. For example, determining U/Ca to reconstruction of sea water temperature or measure the Th/U isotopic ratio for dating to reconstruction sea level etc. However, measuring the U and Th contents and isotopic ratio of corals is a prerequisite for extracting the recorded marine environmental change information, the difficulty lies in the separation of Ca matrix and enrichment and purification of trace U and Th. Based on this, this study modified the pretreatment method of separation and purification U and Th with single column stage of UTEVA resin, and then combined with high resolution inductively coupled plasma mass spectrometry to determine U and Th contents of corals. The results demonstrate that the HNO3 medium concentration decrease from 3 mol/L to 2 mol/L will not affect the absorption efficiency of U and Th; 2 mL Milli-Q water can completely elute U, which significantly reduces the procedure blank value of the entire process of U; the improved method is used to determine the U and Th contents of three Hainan littoral corals (n=6, 1σ): U are (3.46±0.02)μg/g, (2.67±0.05)μg/g, (2.15±0.07)μg/g, respectively, Th are (10.12±0.24)ng/g, (4.82±0.10)ng/g, (5.65±0.12)ng/g, respectively; and the determination accuracy is below 3.3%, recovery rate of standard addition of U, Th are 97.9%–100.9%, 97.3%–99.7%, respectively. The method has high accuracy and good precision. This study provides a more accurate, convenient and rapid experimental method for the analysis of U and Th content and isotopic ratio in corals and other carbonate samples.
2022, 44(2): 143-154.
doi: 10.12284/hyxb2022042
Abstract:
Using 2 000 g kelp as raw material and Karenia mikimotoi as the test microalgae, methanol extraction, liquid-liquid extraction, silica gel column chromatography, sephadax LH-20 gel column chromatography and silica gel thin layer chromatography are used to purify compounds that might inhibit algal activity. Five samples with thin layer purity, B21 (1.39 g), B131 (0.51 g), B132 (0.48 g), C211 (0.016 g) and C212 (0.020 g), are prepared. Structural identification shows that B21, B131, B132, C211 and C212 are 7-hydroxyheptanic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, and oleic acid, respectively. They are isolated from Laminaria japonica for the first time. The results show that these five compounds have selective inhibition effects on the growth of six species of red tide microalgae (Alexandrium tamarense, Amphidinium carterae, Heterosigma akashiwo, Karenia mikimotoi, Phaeocystis globsa, and Skeletonema costatum). Among them, 7-hydroxyheptanoic acid has a wide range of antialgal activities. Except for Alexandrium tamarense, at the concentration of 50 μg/mL, the growth inhibition of 7-hydroxyheptanic acid against the other five species of red tide microalgae is close to that of copper sulfate and potassium dichromate, and the growth inhibition is more than 71% (the 4th day). Tetradecanoic acid also shows obvious inhibition on the growth of Amphidinium carterae, Karenia mikimotoi, and Skeletonema costatum. On 4th day, the growth inhibition of tetradecanoic acid for the three species of red tide microalgae is more than 57%. Furthermore, EC50−96 h values of 7-hydroxyheptanic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid for Amphidinium carterae, Heterosigma akashiwo, Karenia mikimotoi, Phaeocystis globsa, and Skeletonema costatum are obtained for the first time, respectively. EC50−96 h value of 7-hydroxyheptanic acid for Alexandrium tamarense is also determined for the first time. It is found that 7-hydroxyheptanic acid and tetradecanoic acid has the advantage of inhibiting Amphidinium carterae.
Using 2 000 g kelp as raw material and Karenia mikimotoi as the test microalgae, methanol extraction, liquid-liquid extraction, silica gel column chromatography, sephadax LH-20 gel column chromatography and silica gel thin layer chromatography are used to purify compounds that might inhibit algal activity. Five samples with thin layer purity, B21 (1.39 g), B131 (0.51 g), B132 (0.48 g), C211 (0.016 g) and C212 (0.020 g), are prepared. Structural identification shows that B21, B131, B132, C211 and C212 are 7-hydroxyheptanic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, and oleic acid, respectively. They are isolated from Laminaria japonica for the first time. The results show that these five compounds have selective inhibition effects on the growth of six species of red tide microalgae (Alexandrium tamarense, Amphidinium carterae, Heterosigma akashiwo, Karenia mikimotoi, Phaeocystis globsa, and Skeletonema costatum). Among them, 7-hydroxyheptanoic acid has a wide range of antialgal activities. Except for Alexandrium tamarense, at the concentration of 50 μg/mL, the growth inhibition of 7-hydroxyheptanic acid against the other five species of red tide microalgae is close to that of copper sulfate and potassium dichromate, and the growth inhibition is more than 71% (the 4th day). Tetradecanoic acid also shows obvious inhibition on the growth of Amphidinium carterae, Karenia mikimotoi, and Skeletonema costatum. On 4th day, the growth inhibition of tetradecanoic acid for the three species of red tide microalgae is more than 57%. Furthermore, EC50−96 h values of 7-hydroxyheptanic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid for Amphidinium carterae, Heterosigma akashiwo, Karenia mikimotoi, Phaeocystis globsa, and Skeletonema costatum are obtained for the first time, respectively. EC50−96 h value of 7-hydroxyheptanic acid for Alexandrium tamarense is also determined for the first time. It is found that 7-hydroxyheptanic acid and tetradecanoic acid has the advantage of inhibiting Amphidinium carterae.
2022, 44(2): 21-28.
doi: 10.12284/hyxb2022072
Abstract:
According to the bottom trawl survey data of fishery resources in the offshore waters of Shandong from 2016 to 2017, the spatial autocorrelation and spatial heterogeneity of demersal fish in the offshore waters of Shandong were examined by using spatial autocorrelation indices and variogram. The results showed that there were significant spatial aggregation patterns and spatial autocorrelation in the demersal fish in the offshore waters of Shandong. The spatial autocorrelations were strong in spring, summer and winter, and weak in autumn. From the perspective of spatial distribution, the areas of high relative abundance index of demersal fish were mainly located in the southern waters of Shandong in spring and summer, and areas of high relative abundance greatly decreased in autumn and winter, while the areas of low value were mainly in the Laizhou Bay and adjacent waters in four seasons. The parameters of variogram showed that there was a strong nugget effect in autumn, and the spatial heterogeneity of random part accounted for 76.0% of the total spatial heterogeneity. The spatial heterogeneity of random part in spring, summer and winter only accounted for 26.2%, 27.7% and 23.6% of the total spatial heterogeneity. In the spatial autocorrelation and spatial heterogeneity of demersal fish showed seasonal variation in the offshore waters of Shandong, which was to some extent related with changes in environmental factors such as water temperature.
According to the bottom trawl survey data of fishery resources in the offshore waters of Shandong from 2016 to 2017, the spatial autocorrelation and spatial heterogeneity of demersal fish in the offshore waters of Shandong were examined by using spatial autocorrelation indices and variogram. The results showed that there were significant spatial aggregation patterns and spatial autocorrelation in the demersal fish in the offshore waters of Shandong. The spatial autocorrelations were strong in spring, summer and winter, and weak in autumn. From the perspective of spatial distribution, the areas of high relative abundance index of demersal fish were mainly located in the southern waters of Shandong in spring and summer, and areas of high relative abundance greatly decreased in autumn and winter, while the areas of low value were mainly in the Laizhou Bay and adjacent waters in four seasons. The parameters of variogram showed that there was a strong nugget effect in autumn, and the spatial heterogeneity of random part accounted for 76.0% of the total spatial heterogeneity. The spatial heterogeneity of random part in spring, summer and winter only accounted for 26.2%, 27.7% and 23.6% of the total spatial heterogeneity. In the spatial autocorrelation and spatial heterogeneity of demersal fish showed seasonal variation in the offshore waters of Shandong, which was to some extent related with changes in environmental factors such as water temperature.
2022, 44(2): 29-38.
doi: 10.12284/hyxb2022034
Abstract:
According to the data collected in April (spring) and October (autumn) of 2018 in the eastern sea area of Zhoushan Islands (29°10′25.54′′−30°45′00′′N, 122°53′3.88′′−124°48′28.31′′E) based on the crab data obtained from bottom trawl survey of fishery resources, the community structure characteristics of crab resources such as species composition, dominant species and biodiversity were studied, and the relationship between crab quantity distribution and community structure and environmental factors such as temperature and salinity was analyzed. The results show that there are 40 species of crabs in spring and autumn, belonging to 23 genera and 12 families; among them, the dominant species in spring is Charybdis bimaculatus, and in autumn are C. bimaculatus and Portunus trituberculatus; the richness index (D) and Shannon Wiener-diversity index (H′) in autumn are higher than those in spring, while Pielou evenness index (J') is similar in spring and autumn; independent sample t-test show that there is significant difference between spring and autumn; according to cluster analysis and non metric multi-dimensional scaling analysis, spring can be divided into four communities, and autumn can be divided into four communities; canonical correspondence analysis show that bottom water temperature and surface salinity are the main environmental factors affecting the community structure and quantity distribution of crabs in the investigated sea area.
According to the data collected in April (spring) and October (autumn) of 2018 in the eastern sea area of Zhoushan Islands (29°10′25.54′′−30°45′00′′N, 122°53′3.88′′−124°48′28.31′′E) based on the crab data obtained from bottom trawl survey of fishery resources, the community structure characteristics of crab resources such as species composition, dominant species and biodiversity were studied, and the relationship between crab quantity distribution and community structure and environmental factors such as temperature and salinity was analyzed. The results show that there are 40 species of crabs in spring and autumn, belonging to 23 genera and 12 families; among them, the dominant species in spring is Charybdis bimaculatus, and in autumn are C. bimaculatus and Portunus trituberculatus; the richness index (D) and Shannon Wiener-diversity index (H′) in autumn are higher than those in spring, while Pielou evenness index (J') is similar in spring and autumn; independent sample t-test show that there is significant difference between spring and autumn; according to cluster analysis and non metric multi-dimensional scaling analysis, spring can be divided into four communities, and autumn can be divided into four communities; canonical correspondence analysis show that bottom water temperature and surface salinity are the main environmental factors affecting the community structure and quantity distribution of crabs in the investigated sea area.
2022, 44(2): 39-45.
doi: 10.12284/hyxb2022036
Abstract:
According to the seasonal fishery resource survey data from 2016 to 2017 in the adjacent waters of Changshan Islands, two-stage generalized additive model is used to examine the spatio-temporal distribution of Paralichthys olivaceus abundance and its relationships with relevant factors. The results show that the abundance of P. olivaceus exhibites obvious seasonal variation, and the abundances in spring and autumn is higher than those in winter and summer. In spring and autumn, it mainly distributes in the waters of 120.5°−122.5°E; and in summer and winter, it moves to the waters with suitable water temperature. The occurrence probability of P. olivacvacus is mainly affected by season, bottom salinity and bottom temperature. The probability of occurrence is relatively high at the salinity of 31. The relative abundance of P. olivaceus are mainly affected by bottom salinity and depth, and the relative resources is higher at the depth of 33 m. The spatio-temporal heterogeneity of the abundance distribution of P. olivaceus is affected by multiple factors in the adjacent waters of Changshan Islands.
According to the seasonal fishery resource survey data from 2016 to 2017 in the adjacent waters of Changshan Islands, two-stage generalized additive model is used to examine the spatio-temporal distribution of Paralichthys olivaceus abundance and its relationships with relevant factors. The results show that the abundance of P. olivaceus exhibites obvious seasonal variation, and the abundances in spring and autumn is higher than those in winter and summer. In spring and autumn, it mainly distributes in the waters of 120.5°−122.5°E; and in summer and winter, it moves to the waters with suitable water temperature. The occurrence probability of P. olivacvacus is mainly affected by season, bottom salinity and bottom temperature. The probability of occurrence is relatively high at the salinity of 31. The relative abundance of P. olivaceus are mainly affected by bottom salinity and depth, and the relative resources is higher at the depth of 33 m. The spatio-temporal heterogeneity of the abundance distribution of P. olivaceus is affected by multiple factors in the adjacent waters of Changshan Islands.
2022, 44(2): 46-56.
doi: 10.12284/hyxb2022048
Abstract:
This study aims to understand the characteristics and variability in the β diversity of fish community and its influencing environmental factors in the Haizhou Bay, which was rich in fishery resources in history but seriously declined in recent years due to overfishing and environmental pollution. The data were collected from fishery resource surveys conducted in the Haizhou Bay and its adjacent waters from 2013 to 2017 using bottom trawl in autumn. β diversity was measured by Sørensen dissimilarity index using pairwise and multiple-site methods. Additionally, β diversity was divided into turnover and nestedness components and the results were analyzed visually by violin plots. On this basis, the generalized dissimilarity modelling (GDM) was used to analyze the relationship between β diversity and its components with environmental factors. The results of this study showed that the β diversity of fish community and its components fluctuated remarkably among survey years, the fluctuation was larger in the shallow water, less for the deep water, and remained at a relatively stable level regarding the whole sea area. The proportion of the turnover component in β diversity was basically maintained at more than 80%. The component of turnover was significantly larger than that of nestedness, implying the changes of fish community in the Haizhou Bay were dominated by turnover. The salinity and chlorophyll concentration of seawater were the main factors influencing β diversity and its turnover component, and the accumulated deviance explained rate of salinity and chlorophyll were 28.05% and 23.33%, respectively, the influence of water temperature was weak. The environmental factors selected in this study had a low explanatory rate for the nestedness component, which was only 1.52%. Our results implied that the characteristics of fish community have been driven by the environment, and the community development can yield corresponding adaptive to environmental changes. The process of changes in β diversity of fish community may be complex. For instance, salinity and chlorophyll concentration affect the prey density of fish and thus affect β diversity, however, more influencing factors have not been evaluated. Further studies on β diversity and its components are necessary to understand the mechanism of changing characteristics of fish community, and to provide scientific reference for the establishment of marine reserves as well as the optimization of marine conservation strategies.
This study aims to understand the characteristics and variability in the β diversity of fish community and its influencing environmental factors in the Haizhou Bay, which was rich in fishery resources in history but seriously declined in recent years due to overfishing and environmental pollution. The data were collected from fishery resource surveys conducted in the Haizhou Bay and its adjacent waters from 2013 to 2017 using bottom trawl in autumn. β diversity was measured by Sørensen dissimilarity index using pairwise and multiple-site methods. Additionally, β diversity was divided into turnover and nestedness components and the results were analyzed visually by violin plots. On this basis, the generalized dissimilarity modelling (GDM) was used to analyze the relationship between β diversity and its components with environmental factors. The results of this study showed that the β diversity of fish community and its components fluctuated remarkably among survey years, the fluctuation was larger in the shallow water, less for the deep water, and remained at a relatively stable level regarding the whole sea area. The proportion of the turnover component in β diversity was basically maintained at more than 80%. The component of turnover was significantly larger than that of nestedness, implying the changes of fish community in the Haizhou Bay were dominated by turnover. The salinity and chlorophyll concentration of seawater were the main factors influencing β diversity and its turnover component, and the accumulated deviance explained rate of salinity and chlorophyll were 28.05% and 23.33%, respectively, the influence of water temperature was weak. The environmental factors selected in this study had a low explanatory rate for the nestedness component, which was only 1.52%. Our results implied that the characteristics of fish community have been driven by the environment, and the community development can yield corresponding adaptive to environmental changes. The process of changes in β diversity of fish community may be complex. For instance, salinity and chlorophyll concentration affect the prey density of fish and thus affect β diversity, however, more influencing factors have not been evaluated. Further studies on β diversity and its components are necessary to understand the mechanism of changing characteristics of fish community, and to provide scientific reference for the establishment of marine reserves as well as the optimization of marine conservation strategies.
2022, 44(2): 57-66.
doi: 10.12284/hyxb2022044
Abstract:
Cynoglossus semilaevis as a representative species of Pleuronectiformes, is an important marine economic fish in Chinese coastal areas. The abnormal body color of C. semilaevis has been perplexing the practitioners for a long time. There are many reasons leading to abnormal body color, among which the genetic factors are thought to be the most fundamental reasons. The present researches on hypermelanosis of the blind side of C. semilaevis mainly focus on environment, nutrition, physiology, cloning of known pigmental genes and so on, while the digging of new funtional genes is still lacking. In this study, skin samples with different colors of C. semilaevis are selected for transcriptome sequencing. Through GO and KEGG functional enrichment and comparative analysis of different genes, differential expressed genes are screened in six melanogenesis-related KEGG pathways and the top ten genes are verified by qPCR. In this study, we find five functional genes with significant changes in the hypermelanotic skin on the blind side of C. semilaevis, which refer to txndc, alox15b, ptgs2, ptgis, and atp1a2a (p<0.05). The expression levels of txndc, alox15b, ptgs2, and ptgis genes in the melanization group are higher than those in the control group. In terms of function, three of these five genes are related to arachidonic acid (AA) to some extent. This provides theoretical support for the hypothesis that nutritional regulation related to unsaturated fatty acids may be involved in the molecular mechanism of abnormal body color in C. semilaevis.
Cynoglossus semilaevis as a representative species of Pleuronectiformes, is an important marine economic fish in Chinese coastal areas. The abnormal body color of C. semilaevis has been perplexing the practitioners for a long time. There are many reasons leading to abnormal body color, among which the genetic factors are thought to be the most fundamental reasons. The present researches on hypermelanosis of the blind side of C. semilaevis mainly focus on environment, nutrition, physiology, cloning of known pigmental genes and so on, while the digging of new funtional genes is still lacking. In this study, skin samples with different colors of C. semilaevis are selected for transcriptome sequencing. Through GO and KEGG functional enrichment and comparative analysis of different genes, differential expressed genes are screened in six melanogenesis-related KEGG pathways and the top ten genes are verified by qPCR. In this study, we find five functional genes with significant changes in the hypermelanotic skin on the blind side of C. semilaevis, which refer to txndc, alox15b, ptgs2, ptgis, and atp1a2a (p<0.05). The expression levels of txndc, alox15b, ptgs2, and ptgis genes in the melanization group are higher than those in the control group. In terms of function, three of these five genes are related to arachidonic acid (AA) to some extent. This provides theoretical support for the hypothesis that nutritional regulation related to unsaturated fatty acids may be involved in the molecular mechanism of abnormal body color in C. semilaevis.
2022, 44(2): 67-76.
doi: 10.12284/hyxb2022050
Abstract:
Picasso clownfish is named for its disorderly and abstract distribution of white patches in its skin. At the same time, due to the irregular and scarce formation of white patches, it belongs to a valuable clownfish. Therefore, analyzing the formation mechanism of skin white spots in Picasso clownfish can provide a theoretical basis for the artificial breeding of Picasso clownfish. In this study, we sequences the transcriptome of the skin of three color blocks (black, yellow and white） in the same part of the body between the dorsal fin and hip fin of Picasso clownfish. The results show that there are a large number of differentially expressed genes (DEGs） in white skin compared with yellow and black skin. Among them, the genes in the signal pathways related to melanin production (such as melanin production, hedgehog and Wnt signal pathways） show a downward trend in white skin tissue. The expression of upstream regulatory genes (such as ednrba and mitfa） decrease gradually from black to yellow to white skin tissue, but the expression of downstream core genes involved in melanin synthesis (including Tyr, tyrp1b and dct） decreases significantly in white skin assembly. Finally, the validity of transcriptome data is verified by fluorescence quantitative PCR. The results of this study will provide a theoretical basis for future people to interfere with gene expression to regulate clownfish body color.
Picasso clownfish is named for its disorderly and abstract distribution of white patches in its skin. At the same time, due to the irregular and scarce formation of white patches, it belongs to a valuable clownfish. Therefore, analyzing the formation mechanism of skin white spots in Picasso clownfish can provide a theoretical basis for the artificial breeding of Picasso clownfish. In this study, we sequences the transcriptome of the skin of three color blocks (black, yellow and white） in the same part of the body between the dorsal fin and hip fin of Picasso clownfish. The results show that there are a large number of differentially expressed genes (DEGs） in white skin compared with yellow and black skin. Among them, the genes in the signal pathways related to melanin production (such as melanin production, hedgehog and Wnt signal pathways） show a downward trend in white skin tissue. The expression of upstream regulatory genes (such as ednrba and mitfa） decrease gradually from black to yellow to white skin tissue, but the expression of downstream core genes involved in melanin synthesis (including Tyr, tyrp1b and dct） decreases significantly in white skin assembly. Finally, the validity of transcriptome data is verified by fluorescence quantitative PCR. The results of this study will provide a theoretical basis for future people to interfere with gene expression to regulate clownfish body color.
2022, 44(2): 77-83.
doi: 10.12284/hyxb2022068
Abstract:
To clarify the relationship between the glycogen phosphorylase gene (Sc-GPH) and glycogen content in Sinonovacula constricta, the full-length cDNA sequence of Sc-GPH is obtained using RACE technology, its expression pattern in different tissues, different months are analyzed, and the SNP loci of Sc-GPH associated with glycogen content are explored. The full-length cDNA of Sc-GPH gene is 3 963 bp and the ORF is 2 541 bp, encoding 846 amino acids. The multiple alignment of amino acid sequences and phylogenetic tree show that S. constricta are closely related to shellfish such as Pecten maximus, Mizuhopecten yessoens, Crassostrea gigas, but farther to mammals, arthropodas and insects. The results of real-time quantitative PCR show that Sc-GPH gene is expressed in eight tissues, with the highest expression in mantle and foot, suggesting they are related to glycogen storage capacity. In different months, the expression levels of Sc-GPH in the mantle and foot is the highest in August, at which time the glycogen content decreased, indicating that the expression of Sc-GPH seems to be driven by reproductive cycle of S. constricta. In “YL1” population, four SNPs related to glycogen content are screened in the coding region of Sc-GPH gene, and c.930T>C is further verified in Taizhou wild population, which provides a candidate marker for molecular marker assisted breeding of high glycogen S. constricta varieties.
To clarify the relationship between the glycogen phosphorylase gene (Sc-GPH) and glycogen content in Sinonovacula constricta, the full-length cDNA sequence of Sc-GPH is obtained using RACE technology, its expression pattern in different tissues, different months are analyzed, and the SNP loci of Sc-GPH associated with glycogen content are explored. The full-length cDNA of Sc-GPH gene is 3 963 bp and the ORF is 2 541 bp, encoding 846 amino acids. The multiple alignment of amino acid sequences and phylogenetic tree show that S. constricta are closely related to shellfish such as Pecten maximus, Mizuhopecten yessoens, Crassostrea gigas, but farther to mammals, arthropodas and insects. The results of real-time quantitative PCR show that Sc-GPH gene is expressed in eight tissues, with the highest expression in mantle and foot, suggesting they are related to glycogen storage capacity. In different months, the expression levels of Sc-GPH in the mantle and foot is the highest in August, at which time the glycogen content decreased, indicating that the expression of Sc-GPH seems to be driven by reproductive cycle of S. constricta. In “YL1” population, four SNPs related to glycogen content are screened in the coding region of Sc-GPH gene, and c.930T>C is further verified in Taizhou wild population, which provides a candidate marker for molecular marker assisted breeding of high glycogen S. constricta varieties.
2022, 44(2): 84-93.
doi: 10.12284/hyxb2022066
Abstract:
Onchidium struma is widely distributed in intertidal zone and subtidal zone, and considered as a representative species of evolution from ocean to land and an indicator organism for evaluation of environment quality. To enrich the basic immunological data of O. struma, the classification of coelomocytes, cell density and immune-related enzyme activity of the coelomic fluid are studied, and also transcriptome analysis is performed by RNA-Seq sequencing. The results show that there are three different types of coelomocytes, including amoebocytes, spherulocytes and chromatocytes. The number of coelomocytes from more to less are spherulocytes, amoebocytes, chromatocytes. The higher enzyme activities including acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD) and polyphenol oxidase (PO), are detected in coelomic fluids. The activities of SOD and PO are highest. Based on De novo transcriptome analysis, a total of 63 097 unigenes are assembled. KEGG annotations of these unigenes are mostly enriched in “signal transduction” “transport and catabolism” “endocrine system” “translation” “folding, sorting and degradation”, and signalling pathways. The present results will be helpful to further reveal the important role of the body cavity fluid and body coelomocytes in the host immune defense, and enrich the basic immunological data of O. struma.
Onchidium struma is widely distributed in intertidal zone and subtidal zone, and considered as a representative species of evolution from ocean to land and an indicator organism for evaluation of environment quality. To enrich the basic immunological data of O. struma, the classification of coelomocytes, cell density and immune-related enzyme activity of the coelomic fluid are studied, and also transcriptome analysis is performed by RNA-Seq sequencing. The results show that there are three different types of coelomocytes, including amoebocytes, spherulocytes and chromatocytes. The number of coelomocytes from more to less are spherulocytes, amoebocytes, chromatocytes. The higher enzyme activities including acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD) and polyphenol oxidase (PO), are detected in coelomic fluids. The activities of SOD and PO are highest. Based on De novo transcriptome analysis, a total of 63 097 unigenes are assembled. KEGG annotations of these unigenes are mostly enriched in “signal transduction” “transport and catabolism” “endocrine system” “translation” “folding, sorting and degradation”, and signalling pathways. The present results will be helpful to further reveal the important role of the body cavity fluid and body coelomocytes in the host immune defense, and enrich the basic immunological data of O. struma.
2022, 44(2): 94-101.
doi: 10.12284/hyxb2022058
Abstract:
Under the background of global climate change, the continuous high temperature and low salinity caused by extreme short-time heavy rainfall in summer brings severe challenges to pond culture of Apostichopus japonicus. In order to study the physiological responses of A. japonicus to high temperature and low salinity, the effects of collaborative stress of high temperature and low salt on growth and induced hsp70 and hsp90 expression of juvenile A. japonicus were analyzed in this paper. Four temperature gradients (16℃, 20℃, 24℃, and 28℃) and three salinity gradients (22, 27, and 32) were set, and there were a total of 12 different stress groups. After a period of 40 days stress, the weight gain of juvenile A. japonicus decreased with the increase of temperature and the decrease of salinity, there was negative growth in the high temperature and low salinity group. The expression of induced hsp70 and hsp90 was increased after a long period of stress, thus enhancing the resistance of juveniles to extreme weather. Meanwhile, the expression of induced hsps of juveniles treated with salinity 22 was lower than that in the condition of salinity 27. The results of two-factor ANOVA showed that there was no significant interaction between high temperature and low salinity on specific growth rate and induced hsp70 and hsp90 expression, and salinity had no significant effect on induced hsp70 and hsp90 expression. Therefore, compared with low salinity, high temperature had a greater impact on juvenile A. japonicus, which could be used as the selection pressure in A. japonicus breeding. During the high temperature period, effective measures should be taken to reduce the sea temperature and prevent the stratification of aquaculture water caused by extreme weather. This study enriched the physiological and ecological theories of A. japonicus, provided ideas for the breeding of A. japonicus, and provided certain theoretical basis for guiding the production and practice of A. japonicus culture under extreme weather.
Under the background of global climate change, the continuous high temperature and low salinity caused by extreme short-time heavy rainfall in summer brings severe challenges to pond culture of Apostichopus japonicus. In order to study the physiological responses of A. japonicus to high temperature and low salinity, the effects of collaborative stress of high temperature and low salt on growth and induced hsp70 and hsp90 expression of juvenile A. japonicus were analyzed in this paper. Four temperature gradients (16℃, 20℃, 24℃, and 28℃) and three salinity gradients (22, 27, and 32) were set, and there were a total of 12 different stress groups. After a period of 40 days stress, the weight gain of juvenile A. japonicus decreased with the increase of temperature and the decrease of salinity, there was negative growth in the high temperature and low salinity group. The expression of induced hsp70 and hsp90 was increased after a long period of stress, thus enhancing the resistance of juveniles to extreme weather. Meanwhile, the expression of induced hsps of juveniles treated with salinity 22 was lower than that in the condition of salinity 27. The results of two-factor ANOVA showed that there was no significant interaction between high temperature and low salinity on specific growth rate and induced hsp70 and hsp90 expression, and salinity had no significant effect on induced hsp70 and hsp90 expression. Therefore, compared with low salinity, high temperature had a greater impact on juvenile A. japonicus, which could be used as the selection pressure in A. japonicus breeding. During the high temperature period, effective measures should be taken to reduce the sea temperature and prevent the stratification of aquaculture water caused by extreme weather. This study enriched the physiological and ecological theories of A. japonicus, provided ideas for the breeding of A. japonicus, and provided certain theoretical basis for guiding the production and practice of A. japonicus culture under extreme weather.
2022, 44(2): 102-112.
doi: 10.12284/hyxb2022032
Abstract:
Under the long-term influence of climate change and human activities, coral reefs have evolved into special ecosystems with different habitats in the South China Sea. However, the adaptation of corals to special habitats is inseparable from the regulation of endosymbiotic microorganisms. The analysis of ecological characteristics of endosymbiotic microorganisms could help to understand the mechanism of coral host adaptation to environmental changes and the evolutionary trend. In this study, an environmentally sensitive reef-building coral Pocillopora sp. was collected from low latitude Nansha Islands (NS) and Xisha Islands (XS) and the relatively high latitude Hainan Lingshui (LS) in the South China Sea. The community composition and cells density, and environmental correlation of key endosymbiotic microorganisms (Symbiodiniaceae and bacteria) were analyzed. The results showed that: (1) there were great differences in the community composition of Symbiodiniaceae subclades among NS, XS, and LS. The dominant subclades in Pocillopora sp. from NS and XS were D1, C1d, and C42 respectively, while those from LS were C42, C1d, C1p, C1, and C1t; (2) the dominant bacterial compositions included Proteobacteria, Bacteroidetes, and Firmicutes in coral samples from different reef areas, while the relative abundance of Cyanobacteria with photosynthetic function increased significantly with the increase of latitude (from 0.95% of NS to 8.18% of LS, p<0.05); (3) in terms of the number of microbial cells in coral, the density of Symbiodiniaceae increased significantly with the increase of latitude (from (3.39±0.49)×105 cells/cm2 to (8.90±0.65)×105 cells/cm2 coral surface area, p=0.001<0.05), and there was also a higher absolute number of 16S rRNA gene copies in endosymbiotic bacteria in the relatively high latitude LS (p=0.001<0.05); (4) the correlation analysis of environmental factors showed that Symbiodiniaceae subclade D1 with potential thermal tolerance was positively correlated with sea surface temperature and transparency, while subclade C42 and Cyanobacteria were significantly negatively correlated with sea surface temperature and positively correlated with nutrient concentration. This study can provide insight into the micro-ecological mechanism of an environmentally sensitive coral Pocillopora sp. adaptation to environmental change and their evolutionary trend in the South China Sea.
Under the long-term influence of climate change and human activities, coral reefs have evolved into special ecosystems with different habitats in the South China Sea. However, the adaptation of corals to special habitats is inseparable from the regulation of endosymbiotic microorganisms. The analysis of ecological characteristics of endosymbiotic microorganisms could help to understand the mechanism of coral host adaptation to environmental changes and the evolutionary trend. In this study, an environmentally sensitive reef-building coral Pocillopora sp. was collected from low latitude Nansha Islands (NS) and Xisha Islands (XS) and the relatively high latitude Hainan Lingshui (LS) in the South China Sea. The community composition and cells density, and environmental correlation of key endosymbiotic microorganisms (Symbiodiniaceae and bacteria) were analyzed. The results showed that: (1) there were great differences in the community composition of Symbiodiniaceae subclades among NS, XS, and LS. The dominant subclades in Pocillopora sp. from NS and XS were D1, C1d, and C42 respectively, while those from LS were C42, C1d, C1p, C1, and C1t; (2) the dominant bacterial compositions included Proteobacteria, Bacteroidetes, and Firmicutes in coral samples from different reef areas, while the relative abundance of Cyanobacteria with photosynthetic function increased significantly with the increase of latitude (from 0.95% of NS to 8.18% of LS, p<0.05); (3) in terms of the number of microbial cells in coral, the density of Symbiodiniaceae increased significantly with the increase of latitude (from (3.39±0.49)×105 cells/cm2 to (8.90±0.65)×105 cells/cm2 coral surface area, p=0.001<0.05), and there was also a higher absolute number of 16S rRNA gene copies in endosymbiotic bacteria in the relatively high latitude LS (p=0.001<0.05); (4) the correlation analysis of environmental factors showed that Symbiodiniaceae subclade D1 with potential thermal tolerance was positively correlated with sea surface temperature and transparency, while subclade C42 and Cyanobacteria were significantly negatively correlated with sea surface temperature and positively correlated with nutrient concentration. This study can provide insight into the micro-ecological mechanism of an environmentally sensitive coral Pocillopora sp. adaptation to environmental change and their evolutionary trend in the South China Sea.
2022, 44(2): 113-122.
doi: 10.12284/hyxb2022030
Abstract:
The flowing seawater can provide the nutrients for the growth of marine plants, which plays a vital role in the growth and reproduction of marine plants. However, most of the current simulation physiological and ecological experiments ignored this important environmental factor. Although macroalgae is regarded as the emerging fourth category of “blue carbon”, there are few studies on its carbon sequestration. In this study, we design a carbon sequestration capacity measurement system of macroalgae that can adjust the flow speed, which can not only measure the photosynthetic rate, respiratory rate and the absorption rate of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), but also measure the release rate of dissolved organic carbon (DOC) of macroalgae. The results show that the net photosynthetic rate, net primary productivity, DOC release rate and the absorption rate of DIN and DIP of Sargassum thunbergii are increased at medium (0.033 m/s) and high (0.094 m/s) flow speed compared with static status (0 m/s), and the highest values are obtained under high flow speed (0.094 m/s). In addition, the DOC release rate of S. thunbergii increased with the increase of the net primary productivity. This measurement system can provide a practical reference for the study of carbon sequestration capacity of macroalgae.
The flowing seawater can provide the nutrients for the growth of marine plants, which plays a vital role in the growth and reproduction of marine plants. However, most of the current simulation physiological and ecological experiments ignored this important environmental factor. Although macroalgae is regarded as the emerging fourth category of “blue carbon”, there are few studies on its carbon sequestration. In this study, we design a carbon sequestration capacity measurement system of macroalgae that can adjust the flow speed, which can not only measure the photosynthetic rate, respiratory rate and the absorption rate of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), but also measure the release rate of dissolved organic carbon (DOC) of macroalgae. The results show that the net photosynthetic rate, net primary productivity, DOC release rate and the absorption rate of DIN and DIP of Sargassum thunbergii are increased at medium (0.033 m/s) and high (0.094 m/s) flow speed compared with static status (0 m/s), and the highest values are obtained under high flow speed (0.094 m/s). In addition, the DOC release rate of S. thunbergii increased with the increase of the net primary productivity. This measurement system can provide a practical reference for the study of carbon sequestration capacity of macroalgae.
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