2016 Vol. 38, No. 10
Display Method:
2016, 38(10): .
Abstract:
2016, 38(10): .
Abstract:
2016, 38(10): 1-11.
Abstract:
Based on observation and reanalysis data, the ability of 21 CMIP5 models to simulate monthly,seasonal and interannual SSTs in the China seas are evaluated. The results show that the CMIP5 models can simulate the spatial distribution of SST in the China seas well but underestimate its magnitude. The SST difference between the multi-model ensemble and observations is significant in the Bohai Sea and Yellow Sea. As to the interannual timescale, the simulation results and Niño3 index is worse correlated than observation and Niño3 index. The SST in the China seas increases in 1960-2002, but changes to be stable in 2003. Among the 21 CMIP5 models, ACCESS1.0、BCC-CSM1.1,HadGEM2-ES,IPSL-CM5A-MR,CMCC-CM,FGOALS-g2,CNRM-CM5-2 and INMCM4 can simulate the SSTS in the China seas better. The trend of SST in the China seas is simulated based on ACCESS1.0,INMCM4,BCC-CSM1.1,IPSL-CM5A-MR,CMCC-CM. Under RCP4.5, RCP8.5 run, the warming trends of SST will continue in the following 100 years with a spatial average of 1.5℃ and 3.3℃ over the whole China seas. The major cause of SST warming in the East China Sea is sea surface net heat flux and the temperature advection.
Based on observation and reanalysis data, the ability of 21 CMIP5 models to simulate monthly,seasonal and interannual SSTs in the China seas are evaluated. The results show that the CMIP5 models can simulate the spatial distribution of SST in the China seas well but underestimate its magnitude. The SST difference between the multi-model ensemble and observations is significant in the Bohai Sea and Yellow Sea. As to the interannual timescale, the simulation results and Niño3 index is worse correlated than observation and Niño3 index. The SST in the China seas increases in 1960-2002, but changes to be stable in 2003. Among the 21 CMIP5 models, ACCESS1.0、BCC-CSM1.1,HadGEM2-ES,IPSL-CM5A-MR,CMCC-CM,FGOALS-g2,CNRM-CM5-2 and INMCM4 can simulate the SSTS in the China seas better. The trend of SST in the China seas is simulated based on ACCESS1.0,INMCM4,BCC-CSM1.1,IPSL-CM5A-MR,CMCC-CM. Under RCP4.5, RCP8.5 run, the warming trends of SST will continue in the following 100 years with a spatial average of 1.5℃ and 3.3℃ over the whole China seas. The major cause of SST warming in the East China Sea is sea surface net heat flux and the temperature advection.
2016, 38(10): 12-21.
Abstract:
The speciation of heavy metals in marine sediments plays an important role in indicating the pollution status. To explore a concise and effective method to extract the labile fractions of heavy metals (Cr, Cu, Ni, Pb, Zn) and Al, Fe, Mn, we compared the extraction efficacy of 0.1 mol/L HCl, 1 mol/L HCl and BCR procedure for the metals in surface sediments of the Jiaozhou Bay. The results showed that the contents of extracted metals by these three methods had significant positive correlations with each other. The two HCl methods both had high extraction efficiencies for acid-soluble and reducible forms, but lower extraction efficiencies for oxidizable forms. The metals extracted by the BCR procedure had the highest anthropogenic signal index(ASI), indicating that the BCR procedure had the highest extraction efficiency for labile fractions of metals among the three methods. The ASI of metals extracted by 1 mol/L HCl was the lowest, which may be due to that the non-labile fractions of heavy metals in the inner layer of large particles were leached out by the higher acidity, enhancing the pollution signal of heavy metals in sediments. The ASI of Cu, Pb and Zn extracted by 0.1 mol/L HCl was similar to that extracted by the BCR procedure. Furthermore, after the Al normalized, the spatial distribution of labile fraction of heavy metals extracted by 0.1 mol/L HCl were consistent with the actual contamination pattern, demonstrating that 0.1 mol/L HCl extraction method could replace the complex BCR procedure to a certain extent. This method simplify the extraction procedure for labile fractions of heavy metals and is suitable for the large scale evaluation of heavy metal pollution.
The speciation of heavy metals in marine sediments plays an important role in indicating the pollution status. To explore a concise and effective method to extract the labile fractions of heavy metals (Cr, Cu, Ni, Pb, Zn) and Al, Fe, Mn, we compared the extraction efficacy of 0.1 mol/L HCl, 1 mol/L HCl and BCR procedure for the metals in surface sediments of the Jiaozhou Bay. The results showed that the contents of extracted metals by these three methods had significant positive correlations with each other. The two HCl methods both had high extraction efficiencies for acid-soluble and reducible forms, but lower extraction efficiencies for oxidizable forms. The metals extracted by the BCR procedure had the highest anthropogenic signal index(ASI), indicating that the BCR procedure had the highest extraction efficiency for labile fractions of metals among the three methods. The ASI of metals extracted by 1 mol/L HCl was the lowest, which may be due to that the non-labile fractions of heavy metals in the inner layer of large particles were leached out by the higher acidity, enhancing the pollution signal of heavy metals in sediments. The ASI of Cu, Pb and Zn extracted by 0.1 mol/L HCl was similar to that extracted by the BCR procedure. Furthermore, after the Al normalized, the spatial distribution of labile fraction of heavy metals extracted by 0.1 mol/L HCl were consistent with the actual contamination pattern, demonstrating that 0.1 mol/L HCl extraction method could replace the complex BCR procedure to a certain extent. This method simplify the extraction procedure for labile fractions of heavy metals and is suitable for the large scale evaluation of heavy metal pollution.
2016, 38(10): 22-33.
Abstract:
Marine environments are experiencing intense pressures from anthropogenic activities and climate change, management tools or decision support systems are needed to deal with these problems. The classification of marine habitats is the basis and critical to the protection of marine biodiversity and the sustainable usage of marine resources. The identification of ecologically and biologically significant areas (EBSAs) as a objective, scientific and flexible habitat classification and evaluation tool has been widely accepted by the scientists and managers. The present paper began with the introduction of the progress in the concept and identification method of the EBSAs. Then we developed a protocol and a suite of criteria and indicators to identify EBSAs. Finally, application of the methods to Huanghe River Estuary and its adjacent area is presented as a case study based on the integration of all available ecological information we collected. This study is the first trial of EBSAs identification in China coastal areas. The results of our study are expected to provide scientific methods and tools to the ecosystem-based management and provide references to its applications in other areas.
Marine environments are experiencing intense pressures from anthropogenic activities and climate change, management tools or decision support systems are needed to deal with these problems. The classification of marine habitats is the basis and critical to the protection of marine biodiversity and the sustainable usage of marine resources. The identification of ecologically and biologically significant areas (EBSAs) as a objective, scientific and flexible habitat classification and evaluation tool has been widely accepted by the scientists and managers. The present paper began with the introduction of the progress in the concept and identification method of the EBSAs. Then we developed a protocol and a suite of criteria and indicators to identify EBSAs. Finally, application of the methods to Huanghe River Estuary and its adjacent area is presented as a case study based on the integration of all available ecological information we collected. This study is the first trial of EBSAs identification in China coastal areas. The results of our study are expected to provide scientific methods and tools to the ecosystem-based management and provide references to its applications in other areas.
Forecasting fishing ground of Thunnus alalunga based on BP neural network in the South Pacific Ocean
2016, 38(10): 34-43.
Abstract:
Albacore tuna (Thunnus alalunga) is an important target species for Chinese pelagic fishery in the South Pacific Ocean, and the accurate predicting of fishing ground can enhance catch efficiency and improve fishing operation. In this paper, we apply the BP artificial neural network model in the DPS (data processing system) to forecast fishing ground, according to the fishing yield statistics from longline, the sea surface temperature (SST), sea surface height (SST), and ENSO (El Niño-Southern Oscillation) index obtained by satellite remote sensing from 1993 to 2010. We consider the fishing yield (unit is the number of tuna) and CPUE (catch per unit of effort) as the character factors of fishing ground, the same as the output factors in BP artificial neural network respectively, and we take month, latitude, longitude, SST, SSH and ENSO index as the input factors, building the 4-3-1, 5-4-1, 5-3-1, 6-5-1, 6-4-1, 6-3-1 model and choosing the better results. It is found that the model used by CPUE is better than that model used by fishing yield, particularly the 6-4-1 model, and the relatively error is only 0.006 14, which can forecast the fishing ground of Thunnus alalunga in the South Pacific Ocean accurately.
Albacore tuna (Thunnus alalunga) is an important target species for Chinese pelagic fishery in the South Pacific Ocean, and the accurate predicting of fishing ground can enhance catch efficiency and improve fishing operation. In this paper, we apply the BP artificial neural network model in the DPS (data processing system) to forecast fishing ground, according to the fishing yield statistics from longline, the sea surface temperature (SST), sea surface height (SST), and ENSO (El Niño-Southern Oscillation) index obtained by satellite remote sensing from 1993 to 2010. We consider the fishing yield (unit is the number of tuna) and CPUE (catch per unit of effort) as the character factors of fishing ground, the same as the output factors in BP artificial neural network respectively, and we take month, latitude, longitude, SST, SSH and ENSO index as the input factors, building the 4-3-1, 5-4-1, 5-3-1, 6-5-1, 6-4-1, 6-3-1 model and choosing the better results. It is found that the model used by CPUE is better than that model used by fishing yield, particularly the 6-4-1 model, and the relatively error is only 0.006 14, which can forecast the fishing ground of Thunnus alalunga in the South Pacific Ocean accurately.
2016, 38(10): 44-51.
Abstract:
In order to compare the influence degree of surface and thermocline environmental factors on the distribution of albacore tuna fishing ground in the South Pacific quantifiably, this study adopted fishing statistics data of albacore tuna from 21 Chinese longline vessels in the South Pacific during 2010-2012, sea surface temperature (SST)and sea surface height (SSH) data from satellite remote sensing, and upper-bounds and bottom-bounds temperature and depth data of thermocline from Argo buoys, using the outer envelope method to construct three kinds of habitat suitability index (HSI) models based on above environmental variables. Model validation results shows that, HSI model based on sea surface environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 70.04% and the percentage of hook numbers accounting for 70.86%, when HSI is higher than 0.8, the percentage of catch accounting for 24.92% and the percentage of hook numbers accounting for 25.79%; HSI model based on the thermocline upper-bounds environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 82.17% and the percentage of hook numbers accounting for 80.95%, when HSI value is higher than 0.8, the percentage of catch accounting for 33.24% and the percentage of hook numbers accounting for 32.69%; HSI model based on the thermocline bottom-bounds environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 81.01% and the percentage of hook numbers accounted for 81.54%, when HSI value is higher than 0.8, the percentage of catch accounting for 43.51%and the percentage of hook numbers accounted for 43.73%. The analysis shows that, compared to the sea surface environment, the thermocline environment, especially the effect of the thermocline bottom-bounds environmental characteristics is more significant to the distribution of South Pacific albacore tuna resource.
In order to compare the influence degree of surface and thermocline environmental factors on the distribution of albacore tuna fishing ground in the South Pacific quantifiably, this study adopted fishing statistics data of albacore tuna from 21 Chinese longline vessels in the South Pacific during 2010-2012, sea surface temperature (SST)and sea surface height (SSH) data from satellite remote sensing, and upper-bounds and bottom-bounds temperature and depth data of thermocline from Argo buoys, using the outer envelope method to construct three kinds of habitat suitability index (HSI) models based on above environmental variables. Model validation results shows that, HSI model based on sea surface environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 70.04% and the percentage of hook numbers accounting for 70.86%, when HSI is higher than 0.8, the percentage of catch accounting for 24.92% and the percentage of hook numbers accounting for 25.79%; HSI model based on the thermocline upper-bounds environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 82.17% and the percentage of hook numbers accounting for 80.95%, when HSI value is higher than 0.8, the percentage of catch accounting for 33.24% and the percentage of hook numbers accounting for 32.69%; HSI model based on the thermocline bottom-bounds environmental variables, when HSI value is higher than 0.6, the percentage of catch accounting for 81.01% and the percentage of hook numbers accounted for 81.54%, when HSI value is higher than 0.8, the percentage of catch accounting for 43.51%and the percentage of hook numbers accounted for 43.73%. The analysis shows that, compared to the sea surface environment, the thermocline environment, especially the effect of the thermocline bottom-bounds environmental characteristics is more significant to the distribution of South Pacific albacore tuna resource.
2016, 38(10): 52-61.
Abstract:
The small-sized fish species in Clupeidae and Engraulidae are important components in marine ecosystem, as most of them feed on plankton and are food resources for fishes with high trophic levels. Regarding the important ecological roles, their spatiotemporal distribution has an important influence on a variety of organisms. The distribution of this taxon and its relationship with environmental factors was analyzed using generalized additive models (GAM) based on the data collected from the bottom trawl surveys conducted in June, August, October 2013 and February, April, May 2014 in the Huanghe River Estuary and its adjacent waters. The relative abundance of the small-sized fish species in Clupeidae and Engraulidae varied remarkably among seasons, and the relative abundance was higher in summer and autumn and lower in spring and winter. This taxon had significant spatial variation and showed different distribution patterns among months. These species aggregated in the coastal waters of the estuary in April, May and June and moved outward and expanded their distribution in August and October. GAM analysis showed that the spatio-temporal distribution of these species were influenced by several main factors, including sea surface salinity and sea surface temperature, depth and phytoplankton abundance in the Yellow River Estuary. Surface salinity had the most significant effect on the relative abundance of the species in Clupeidae and Engraulidae. The relative abundance was positively corrected with surface salinity and maintained at a high level with surface salinity of 30. The surface water temperature also had a positive effect on the relative abundance of the species in Clupeidae and Engraulidae, and the abundance maintained at a high level when SST was higher than 15℃. The phytoplankton abundance was positively correlated with fish abundance, whereas depth showed a concave-shaped correlation. It is inferred that the distribution of fish species in Clupeidae and Engraulidae could be ascribed to their spawning, feeding behaviors and overwintering migration, driven by the seasonal changes in marine environment and other environmental changes caused by the runoff and sand-washing operation of the Huanghe River.
The small-sized fish species in Clupeidae and Engraulidae are important components in marine ecosystem, as most of them feed on plankton and are food resources for fishes with high trophic levels. Regarding the important ecological roles, their spatiotemporal distribution has an important influence on a variety of organisms. The distribution of this taxon and its relationship with environmental factors was analyzed using generalized additive models (GAM) based on the data collected from the bottom trawl surveys conducted in June, August, October 2013 and February, April, May 2014 in the Huanghe River Estuary and its adjacent waters. The relative abundance of the small-sized fish species in Clupeidae and Engraulidae varied remarkably among seasons, and the relative abundance was higher in summer and autumn and lower in spring and winter. This taxon had significant spatial variation and showed different distribution patterns among months. These species aggregated in the coastal waters of the estuary in April, May and June and moved outward and expanded their distribution in August and October. GAM analysis showed that the spatio-temporal distribution of these species were influenced by several main factors, including sea surface salinity and sea surface temperature, depth and phytoplankton abundance in the Yellow River Estuary. Surface salinity had the most significant effect on the relative abundance of the species in Clupeidae and Engraulidae. The relative abundance was positively corrected with surface salinity and maintained at a high level with surface salinity of 30. The surface water temperature also had a positive effect on the relative abundance of the species in Clupeidae and Engraulidae, and the abundance maintained at a high level when SST was higher than 15℃. The phytoplankton abundance was positively correlated with fish abundance, whereas depth showed a concave-shaped correlation. It is inferred that the distribution of fish species in Clupeidae and Engraulidae could be ascribed to their spawning, feeding behaviors and overwintering migration, driven by the seasonal changes in marine environment and other environmental changes caused by the runoff and sand-washing operation of the Huanghe River.
2016, 38(10): 62-69.
Abstract:
Carbon and nitrogen stable isotope analyses were employed to explore the dietary composition and trophic position of P. pelagicus in Honghai Bay based on samples collected in May 2015. The results showed that, the average δ13C and δ15N values of the P. pelagicus were -16.9‰±1.3‰ and 12.1‰±2.3‰, in a range of -18.1‰ to -14.1‰ and 9.8‰ to 13.8‰, respectively, indicated that P. pelagicus feed on numerous prey species. Potential food sources of P. pelagicus were bivalves, snails, fishes, cephalopods, shrimps, crabs and algaes. Algaes were the most important prey of P. pelagicus by averagely contributing 32.5% to the diet, followed by bivalves (21.9%), shrimps (9.7%), snails (9.7%), fishes (9.6%), crabs (9.3%) and cephalopods (7.3%). The average trophic position of P. pelagicus was 2.91±0.68, and algaes, bivalves, crabs, snails, shrimps, fishes as well as cephalopods' trophic positon were 1.21±0.58, 2.00±0.25, 2.85±0.33, 2.87±0.26, 3.01±0.16, 3.08±0.18 and 3.41±0.17 respectively.
Carbon and nitrogen stable isotope analyses were employed to explore the dietary composition and trophic position of P. pelagicus in Honghai Bay based on samples collected in May 2015. The results showed that, the average δ13C and δ15N values of the P. pelagicus were -16.9‰±1.3‰ and 12.1‰±2.3‰, in a range of -18.1‰ to -14.1‰ and 9.8‰ to 13.8‰, respectively, indicated that P. pelagicus feed on numerous prey species. Potential food sources of P. pelagicus were bivalves, snails, fishes, cephalopods, shrimps, crabs and algaes. Algaes were the most important prey of P. pelagicus by averagely contributing 32.5% to the diet, followed by bivalves (21.9%), shrimps (9.7%), snails (9.7%), fishes (9.6%), crabs (9.3%) and cephalopods (7.3%). The average trophic position of P. pelagicus was 2.91±0.68, and algaes, bivalves, crabs, snails, shrimps, fishes as well as cephalopods' trophic positon were 1.21±0.58, 2.00±0.25, 2.85±0.33, 2.87±0.26, 3.01±0.16, 3.08±0.18 and 3.41±0.17 respectively.
2016, 38(10): 70-82.
Abstract:
Hyperiid community characteristics were analyzed using net and concurrent environmental data obtained during seasons of 2013. We evaluated the effect of monsoon changing on hyperrid community and the correlation between hyperiid and siphonophire. We identified 63 species comprised of 26 genera within 12 families for the hyperiid community. This hyperiid community can be divided into three groups:spring group, summer group and autumn-winter group. Hyperiid fauna belongs to the typical tropical ocean region with two ecotypes:the oceanic ecotype with more species and the euryhaline ecotype with higher abundance. Seven seasonal dominant species were Lestrigonus bengalensi, Eupronoe intermedia, E. maculate, Phronima sedentaria, Lycaeopsis zamboanmgae, Tetrathyrus forcipatus and Amphithyrus muratus while L. bengalensi was the annual dominant specieswith noticeable domination. The annual mean of hyperiid abundance was 18.30×10-2 ind/m3 and annually abundant hyperiid distributed on the continental shelf. The seasonal means of hyperiid abundance were consistent while the seasonal horizontal distributions showed significant differences through seasons. The annual means of hyperiid richness index, diversity index, evenness index and diversity threshold were 1.23, 1.28, 0.33 and 0.48, respectively. Hyperiid composition changed along with the effect of monsoon reversal on the expending and shrinking of coastal hypohaline waters. The horizontal distribution of hyperiid abundance and diversity threshold changed along with the surface currents driven by monsoon reversal. The correlation analysis indicates a symbiosis relationship between hyperiid and siphonophore in Nansha Islands waters. Due to such a symbiosis, L. bengalensi dominates upon the effect of coastal hypohaline waters in-flowed, showing the similarity to the dominant species in coastal ocean.
Hyperiid community characteristics were analyzed using net and concurrent environmental data obtained during seasons of 2013. We evaluated the effect of monsoon changing on hyperrid community and the correlation between hyperiid and siphonophire. We identified 63 species comprised of 26 genera within 12 families for the hyperiid community. This hyperiid community can be divided into three groups:spring group, summer group and autumn-winter group. Hyperiid fauna belongs to the typical tropical ocean region with two ecotypes:the oceanic ecotype with more species and the euryhaline ecotype with higher abundance. Seven seasonal dominant species were Lestrigonus bengalensi, Eupronoe intermedia, E. maculate, Phronima sedentaria, Lycaeopsis zamboanmgae, Tetrathyrus forcipatus and Amphithyrus muratus while L. bengalensi was the annual dominant specieswith noticeable domination. The annual mean of hyperiid abundance was 18.30×10-2 ind/m3 and annually abundant hyperiid distributed on the continental shelf. The seasonal means of hyperiid abundance were consistent while the seasonal horizontal distributions showed significant differences through seasons. The annual means of hyperiid richness index, diversity index, evenness index and diversity threshold were 1.23, 1.28, 0.33 and 0.48, respectively. Hyperiid composition changed along with the effect of monsoon reversal on the expending and shrinking of coastal hypohaline waters. The horizontal distribution of hyperiid abundance and diversity threshold changed along with the surface currents driven by monsoon reversal. The correlation analysis indicates a symbiosis relationship between hyperiid and siphonophore in Nansha Islands waters. Due to such a symbiosis, L. bengalensi dominates upon the effect of coastal hypohaline waters in-flowed, showing the similarity to the dominant species in coastal ocean.
2016, 38(10): 83-93.
Abstract:
Based on the zooplankton samples from stations in Beilun Estuary, Jiulongjiang Estuary, Oujiang Estuary, Changjiang Estuary (Yangtze River) and Guanhe Estuary(covering 14 latitudes) in April or May of 2010 to 2012, the community features of Diversity index(H'), replacement rate(R) and similarity coefficient(S) were compared. This paper also analyzed the variation and reasons of zooplankton community in different estuaries. The results indicated that the zooplankton community of the five estuaries were divided into three different zooplankton fauna, which were the southern subtropical, central transitional and northern temperate from the south to the north. The southern subtropical zooplankton fauna included Beilun Estuary and Jiulong Estuary. In this fauna, the subtropical species was the mainly and a different diversity index (H') (1.01 and 2.18) were recorded, located in the subtropical sea. There placement rate(R) and similarity coefficient(S) were respectively 65.52% and 51.28% between Beilun Estuary and Jiulong Estuary. In central transitional zooplankton fauna, constituted by Oujiang Estuary and Changjiang Estuary, it was exclusively of the subtropical species and warm temperate species, which had an alike diversity index (H') (1.31 and 1.86, respectively), situated in the transition waters between subtropical and temperate. Between the two estuaries, the replacement rate(R) were lowest (58.33%) and the similarity coefficient(S) were highest (58.82%). At high latitude, only the Guanhe Estuary belongs to the northern temperate, the warm temperate species was dominated, which had a lower diversity index (H') (1.19) and located in the temperate sea. The replacement rate(R) and similarity coefficient(S) of Guanhe Estuary were significantly different from the other estuaries. From south to north, along with the increase of latitude, the structure of estuarine zooplankton community has changed significantly. Linear regression figured that replacement rate(R) was positively correlated with the difference of longitude between the two estuaries in Chinese (ΔN), R=0.026ΔN+0.608(p=0.002). Similarity coefficient(S) was negatively correlated with the difference of longitude (ΔN), S=-0.034ΔN+0.578(p=0.001). In spring, the main reasons which caused the variation of zooplankton community between different estuaries was due to the difference of the influence of temperature and water masses.
Based on the zooplankton samples from stations in Beilun Estuary, Jiulongjiang Estuary, Oujiang Estuary, Changjiang Estuary (Yangtze River) and Guanhe Estuary(covering 14 latitudes) in April or May of 2010 to 2012, the community features of Diversity index(H'), replacement rate(R) and similarity coefficient(S) were compared. This paper also analyzed the variation and reasons of zooplankton community in different estuaries. The results indicated that the zooplankton community of the five estuaries were divided into three different zooplankton fauna, which were the southern subtropical, central transitional and northern temperate from the south to the north. The southern subtropical zooplankton fauna included Beilun Estuary and Jiulong Estuary. In this fauna, the subtropical species was the mainly and a different diversity index (H') (1.01 and 2.18) were recorded, located in the subtropical sea. There placement rate(R) and similarity coefficient(S) were respectively 65.52% and 51.28% between Beilun Estuary and Jiulong Estuary. In central transitional zooplankton fauna, constituted by Oujiang Estuary and Changjiang Estuary, it was exclusively of the subtropical species and warm temperate species, which had an alike diversity index (H') (1.31 and 1.86, respectively), situated in the transition waters between subtropical and temperate. Between the two estuaries, the replacement rate(R) were lowest (58.33%) and the similarity coefficient(S) were highest (58.82%). At high latitude, only the Guanhe Estuary belongs to the northern temperate, the warm temperate species was dominated, which had a lower diversity index (H') (1.19) and located in the temperate sea. The replacement rate(R) and similarity coefficient(S) of Guanhe Estuary were significantly different from the other estuaries. From south to north, along with the increase of latitude, the structure of estuarine zooplankton community has changed significantly. Linear regression figured that replacement rate(R) was positively correlated with the difference of longitude between the two estuaries in Chinese (ΔN), R=0.026ΔN+0.608(p=0.002). Similarity coefficient(S) was negatively correlated with the difference of longitude (ΔN), S=-0.034ΔN+0.578(p=0.001). In spring, the main reasons which caused the variation of zooplankton community between different estuaries was due to the difference of the influence of temperature and water masses.
2016, 38(10): 94-104.
Abstract:
Paracalanus sp., which has been identified as Paracalanus parvus by previous reports in the northern part of China seas, is a very common small copepod in Laizhou Bay, Bohai Sea. The species is characterized ecologically by a high level of secondary productivity and a suitable food resource for early larvae of fishes in the bay. To explore the population dynamic in Laizhou Bay, copepodites and adult data of Paracalanus sp. were collected and analyzed from 147 samples over the annual surveys from May 2011 to April 2012 (excluding December 2011 and January and February 2012, because of the presence of sea ice). The results showed Paracalanus sp. occurred continuously in the plankton throughout the year, with an enormous peak in August. Its stage-specific population structure and body size fluctuated greatly during the study period. During the surveyed seasons, copepodites stages CⅢ, CⅣ and CⅤ contributed most percentages in total population abundance except that from April to June when the adults became dominant. Of the copepodite stages, CⅣ and CⅤ accounted for the largest proportion of the total population abundance from October to March. In the adult, pronounced dominance of females over males was found throughout the year. The female to male ratios ranged from 1.46 to 9.62, with the lowest value in March and April and highest in October and November. The body size of Paracalanus sp. changed seasonally, being the largest in April or May, and the smallest in August. Mean body size of each developmental stage was inversely related to temperature at the time of sampling by regression statistic. The biomass of Paracalanus sp. showed marked seasonal variations largely in parallel with numerical abundance. Its monthly mean value was 2.69 mg/m3. The species production rate was estimated with 0.74 mg/(m3·d) based on the reported experienced equation. From above results, the annual population dynamic of Paracalanus sp. could be divided into three main phases, starting breeding phase from April to June, rapid population growth phase from July to August, and relative population growth stagnation phase just after September.
Paracalanus sp., which has been identified as Paracalanus parvus by previous reports in the northern part of China seas, is a very common small copepod in Laizhou Bay, Bohai Sea. The species is characterized ecologically by a high level of secondary productivity and a suitable food resource for early larvae of fishes in the bay. To explore the population dynamic in Laizhou Bay, copepodites and adult data of Paracalanus sp. were collected and analyzed from 147 samples over the annual surveys from May 2011 to April 2012 (excluding December 2011 and January and February 2012, because of the presence of sea ice). The results showed Paracalanus sp. occurred continuously in the plankton throughout the year, with an enormous peak in August. Its stage-specific population structure and body size fluctuated greatly during the study period. During the surveyed seasons, copepodites stages CⅢ, CⅣ and CⅤ contributed most percentages in total population abundance except that from April to June when the adults became dominant. Of the copepodite stages, CⅣ and CⅤ accounted for the largest proportion of the total population abundance from October to March. In the adult, pronounced dominance of females over males was found throughout the year. The female to male ratios ranged from 1.46 to 9.62, with the lowest value in March and April and highest in October and November. The body size of Paracalanus sp. changed seasonally, being the largest in April or May, and the smallest in August. Mean body size of each developmental stage was inversely related to temperature at the time of sampling by regression statistic. The biomass of Paracalanus sp. showed marked seasonal variations largely in parallel with numerical abundance. Its monthly mean value was 2.69 mg/m3. The species production rate was estimated with 0.74 mg/(m3·d) based on the reported experienced equation. From above results, the annual population dynamic of Paracalanus sp. could be divided into three main phases, starting breeding phase from April to June, rapid population growth phase from July to August, and relative population growth stagnation phase just after September.
2016, 38(10): 105-112.
Abstract:
It has been proved that there are more algal spores settled on rough surface than on smooth surface. However, the effect of surface roughness on algal density has not been tested. In this study, two substrate material NYLON and PMMA were suspended in the sea to get algal propagules attaching and developing. Densities of four species of seaweeds Polysiphonia urceolata, Urospora penicilliformis, Punctaria latifolia and Chaetomorpha antennina were counted on 6 different roughness surfaces. The ANOVA show that there is significantly less sporelings on smooth surface (without depression) than on any rough surface (with any of six densities of depression). However, different roughness on substrate surface has no significant impact on seaweed density. In the experiment in a greenhouse with filtered seawater, surface roughness on NYLON substrate significantly impact sporeling density of Laminaria japonica. However, when the substrate with Laminaria japonica sporelings were transferred and suspended into the sea for 8 days, most sporelings were removed and the roughness had no significant impact on the algal density. The possible effects of zooplankton grazing and hydrodynamic forces in the sea decreasing algal adhesion are discussed. 3 types of sediment, sea mud, sterial-sea-mud and diatom were settled on substrate surface to test the affect on algal density. The results show that the affect of sediment and roughness and the interaction between them on algal density depends on the algal species and substrate materials.
It has been proved that there are more algal spores settled on rough surface than on smooth surface. However, the effect of surface roughness on algal density has not been tested. In this study, two substrate material NYLON and PMMA were suspended in the sea to get algal propagules attaching and developing. Densities of four species of seaweeds Polysiphonia urceolata, Urospora penicilliformis, Punctaria latifolia and Chaetomorpha antennina were counted on 6 different roughness surfaces. The ANOVA show that there is significantly less sporelings on smooth surface (without depression) than on any rough surface (with any of six densities of depression). However, different roughness on substrate surface has no significant impact on seaweed density. In the experiment in a greenhouse with filtered seawater, surface roughness on NYLON substrate significantly impact sporeling density of Laminaria japonica. However, when the substrate with Laminaria japonica sporelings were transferred and suspended into the sea for 8 days, most sporelings were removed and the roughness had no significant impact on the algal density. The possible effects of zooplankton grazing and hydrodynamic forces in the sea decreasing algal adhesion are discussed. 3 types of sediment, sea mud, sterial-sea-mud and diatom were settled on substrate surface to test the affect on algal density. The results show that the affect of sediment and roughness and the interaction between them on algal density depends on the algal species and substrate materials.
2016, 38(10): 113-124.
Abstract:
Understanding the mechanism by which environmental factors affects phytoplankton growth in summer is essential for determining polar marine ecosystem responses to global climate change. Here we deployed an online mooring system in Great Wall Bay to determine how current velocity and local physical forcing affect the temporal and spatial distribution of phytoplankton biomass in Antarctic coastal waters. The results show that chlorophyll a(Chl a)concentrations accumulated from mid-December and two significant blooms developed in January (2.74 μg/L and 3.76 μg/L) and were then maintained at a relatively high level. The diurnal variations of cholorophyll a concentrations were observed in both upper and middle layers during the monitoring period. The surface current velocity reached approximately (60-100)cm/s, while the middle and bottom current velocity was limited to about 10 cm/s. We conclude that summer winds played an important role in the surface current velocity and direction. The monitoring site appears to exchange with adjacent oceanic waters, such an intrusion of water would bring in varied phytoplankton species. The results of Pearson correlation analysis showed the significant and positive influence of low current velocity on chlorophyll a concentrations, especially during phytoplankton blooms, whereas the increased current velocity showed the significant and negative correlations with phytoplankton biomass.
Understanding the mechanism by which environmental factors affects phytoplankton growth in summer is essential for determining polar marine ecosystem responses to global climate change. Here we deployed an online mooring system in Great Wall Bay to determine how current velocity and local physical forcing affect the temporal and spatial distribution of phytoplankton biomass in Antarctic coastal waters. The results show that chlorophyll a(Chl a)concentrations accumulated from mid-December and two significant blooms developed in January (2.74 μg/L and 3.76 μg/L) and were then maintained at a relatively high level. The diurnal variations of cholorophyll a concentrations were observed in both upper and middle layers during the monitoring period. The surface current velocity reached approximately (60-100)cm/s, while the middle and bottom current velocity was limited to about 10 cm/s. We conclude that summer winds played an important role in the surface current velocity and direction. The monitoring site appears to exchange with adjacent oceanic waters, such an intrusion of water would bring in varied phytoplankton species. The results of Pearson correlation analysis showed the significant and positive influence of low current velocity on chlorophyll a concentrations, especially during phytoplankton blooms, whereas the increased current velocity showed the significant and negative correlations with phytoplankton biomass.
2016, 38(10): 125-134.
Abstract:
Based on the data of zooplankton and relative environmental factors investigated in the South Yellow Sea (32°20'-37°00'N, west of 124°E) during October to December, 2007, species composition, distribution pattern of zooplankton and their influencing factors were analysed. Results are as follows:113 species of zooplankton were identified (not including 25 planktonic larvae), Calanus sinicus, Aidanosagitta crassa, Euphausia larvae and Doliolum denticulatum were the dominant species; the abundance and biomass of zooplankton in our cruise was (156.37±12.04) ind/m3 and (172.57±10.41) mg/m3, respectively, which remained at a high level compared with historical data; distribution pattern of Euphausia larvae was in accordance with that of Pseudeuphausia sinica, therefore, autumn is a critical period for the population recruitment of P. sinica; the mass occurance of D. denticulatum was the result of population recruitment; the distribution area of Euchaeta concinna and Flaccisagitta enflata was located in the deeper water and the two species rarely occurred in coastal waters; high abundance of C. sinicus and A. crassa tended to occur near the oceanic front, which further testified the accumulation effect of oceanic front on zooplankton species.
Based on the data of zooplankton and relative environmental factors investigated in the South Yellow Sea (32°20'-37°00'N, west of 124°E) during October to December, 2007, species composition, distribution pattern of zooplankton and their influencing factors were analysed. Results are as follows:113 species of zooplankton were identified (not including 25 planktonic larvae), Calanus sinicus, Aidanosagitta crassa, Euphausia larvae and Doliolum denticulatum were the dominant species; the abundance and biomass of zooplankton in our cruise was (156.37±12.04) ind/m3 and (172.57±10.41) mg/m3, respectively, which remained at a high level compared with historical data; distribution pattern of Euphausia larvae was in accordance with that of Pseudeuphausia sinica, therefore, autumn is a critical period for the population recruitment of P. sinica; the mass occurance of D. denticulatum was the result of population recruitment; the distribution area of Euchaeta concinna and Flaccisagitta enflata was located in the deeper water and the two species rarely occurred in coastal waters; high abundance of C. sinicus and A. crassa tended to occur near the oceanic front, which further testified the accumulation effect of oceanic front on zooplankton species.
Email alert
RSS