2017 Vol. 39, No. 10
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2017, 39(10): .
Abstract:
2017, 39(10): 1-18.
doi: 10.3969/j.issn.0253-4193.2017.10.001
Abstract:
The ecological effects of fisheries and other human activities are increasingly concerned with the better understanding of marine ecosystems. Consequently, the concept of "ecosystem-based fisheries management" (EBFM) have been widely accepted by a range of researchers and institutes, for which ecological models have contributed to the basis of scientific methods and useful tools. Comparing to the singe-species assessment models, ecological models are superior in handling various ecological processes and mechanisms, habitat and environmental changes, and the structure and functions of ecosystems. Ecological models diversify in modeling objectives, mechanistic processes, model structure and parameters, and this study classified prevalent models into three categories on the basis of their ecological levels and components:multispecies models, community structure models and ecosystem models. We elaborated the advantages and disadvantages for each category of ecological models separately. We briefly introduced their potential use in guiding fisheries management on the basis of management strategy evaluation (MSE), and the caveats in model selection, building and implementation. Furthermore, we discussed the future development of ecological modeling in reducing uncertainty and improve predictability.
The ecological effects of fisheries and other human activities are increasingly concerned with the better understanding of marine ecosystems. Consequently, the concept of "ecosystem-based fisheries management" (EBFM) have been widely accepted by a range of researchers and institutes, for which ecological models have contributed to the basis of scientific methods and useful tools. Comparing to the singe-species assessment models, ecological models are superior in handling various ecological processes and mechanisms, habitat and environmental changes, and the structure and functions of ecosystems. Ecological models diversify in modeling objectives, mechanistic processes, model structure and parameters, and this study classified prevalent models into three categories on the basis of their ecological levels and components:multispecies models, community structure models and ecosystem models. We elaborated the advantages and disadvantages for each category of ecological models separately. We briefly introduced their potential use in guiding fisheries management on the basis of management strategy evaluation (MSE), and the caveats in model selection, building and implementation. Furthermore, we discussed the future development of ecological modeling in reducing uncertainty and improve predictability.
2017, 39(10): 19-31.
doi: 10.3969/j.issn.0253-4193.2017.10.002
Abstract:
Organic carbon (OC) buried in the marine sediments performs as the net sink of atmosphere CO2. The Arctic Ocean has the largest shelf and receives a mass of terrestrial OC transported by the rivers and coastal weathering. The Chukchi Sea is one of the marginal seas of the Arctic Ocean where terrestrial OC was buried. In this study, surface sediments from the Chukchi Sea and plateau are selected and divided into two groups:the shelf (33-82.69 m) and the slope (164.63-3 763 m). Lignin phenols, in combined with stable carbon isotope (δ13C), OC%, grain size and specific surface area (SSA) are used to trace the sources and degradation of terrestrial organic carbon in this region. The results show that OC loading decrees dramatically from the shelf to the slope. The wide range of δ13C shows a multi-sourced contribution of plants like shrubs, grasses, and conifers. Gymnosperm tissue is relatively more dominant than angiosperm tissue, whereas non-woody tissue is more dominant than woody tissue upon the surface sediments of the Chukchi Sea, according to the C/V and S/V ratios. In addition, the C9DA, which is obtained from the aliphatic-rich kerogen, is relatively high among Das. This implies that kerogen can play a pregnant role in the sources of the OC in the Chukchi Sea and Plateau.
Organic carbon (OC) buried in the marine sediments performs as the net sink of atmosphere CO2. The Arctic Ocean has the largest shelf and receives a mass of terrestrial OC transported by the rivers and coastal weathering. The Chukchi Sea is one of the marginal seas of the Arctic Ocean where terrestrial OC was buried. In this study, surface sediments from the Chukchi Sea and plateau are selected and divided into two groups:the shelf (33-82.69 m) and the slope (164.63-3 763 m). Lignin phenols, in combined with stable carbon isotope (δ13C), OC%, grain size and specific surface area (SSA) are used to trace the sources and degradation of terrestrial organic carbon in this region. The results show that OC loading decrees dramatically from the shelf to the slope. The wide range of δ13C shows a multi-sourced contribution of plants like shrubs, grasses, and conifers. Gymnosperm tissue is relatively more dominant than angiosperm tissue, whereas non-woody tissue is more dominant than woody tissue upon the surface sediments of the Chukchi Sea, according to the C/V and S/V ratios. In addition, the C9DA, which is obtained from the aliphatic-rich kerogen, is relatively high among Das. This implies that kerogen can play a pregnant role in the sources of the OC in the Chukchi Sea and Plateau.
2017, 39(10): 32-45.
doi: 10.3969/j.issn.0253-4193.2017.10.003
Abstract:
The west-central Pacific Ocean is the world's most important fishing ground for skipjack tuna (katsuwonus pelamis), this fishing area is always impact by ocean environment, especially sea surface temperature (SST) and Niño 3.4 index(SSTA). However, the fishing ground of skipjack tuna is widely distributed in the waters of many island countries, how to scientific guide the entry-fishing is an important studying object. According to the production data of skipjack tuna in the west-central Pacific Ocean during 1995-2012, and the total of 22 fishing zones (5°×5°) with the high catch are selected to analyze the spatial variation of fishing effort for skipjack tuna in central-west Pacific Ocean. The percentage of fishing effort is also regarded as the index of entry-fishing, and the optimal entry-fishing model between the index of entry-fishing and SST or SSTA is established. The results showed that main fishing efforts were focused in the area of 5°S-5°N in the direction of latitude, accounting for 87.4% of the total fishing effort. The area of 130°-140°E was the major fishing zone area in the longitudinal direction, accounting for 45.08% of the total fishing effort in the 22 fishing zones. The relationships between the index of entry-fishing and SSTA or SST all showed the normal distribution (P<0.01) for each fishing zone. The suitable value of SSTA model was on early 0.25℃, and the suitable value of SST model was nearly 29.5℃. For the top 10 ranking of entry-fishing index, we find that the actual index and predicted value is the same. It is concluded that this entry-fishing forecasting model can effectively predict fishing area distribution, which could give us a suitable advice for fisheries industries in the future.
The west-central Pacific Ocean is the world's most important fishing ground for skipjack tuna (katsuwonus pelamis), this fishing area is always impact by ocean environment, especially sea surface temperature (SST) and Niño 3.4 index(SSTA). However, the fishing ground of skipjack tuna is widely distributed in the waters of many island countries, how to scientific guide the entry-fishing is an important studying object. According to the production data of skipjack tuna in the west-central Pacific Ocean during 1995-2012, and the total of 22 fishing zones (5°×5°) with the high catch are selected to analyze the spatial variation of fishing effort for skipjack tuna in central-west Pacific Ocean. The percentage of fishing effort is also regarded as the index of entry-fishing, and the optimal entry-fishing model between the index of entry-fishing and SST or SSTA is established. The results showed that main fishing efforts were focused in the area of 5°S-5°N in the direction of latitude, accounting for 87.4% of the total fishing effort. The area of 130°-140°E was the major fishing zone area in the longitudinal direction, accounting for 45.08% of the total fishing effort in the 22 fishing zones. The relationships between the index of entry-fishing and SSTA or SST all showed the normal distribution (P<0.01) for each fishing zone. The suitable value of SSTA model was on early 0.25℃, and the suitable value of SST model was nearly 29.5℃. For the top 10 ranking of entry-fishing index, we find that the actual index and predicted value is the same. It is concluded that this entry-fishing forecasting model can effectively predict fishing area distribution, which could give us a suitable advice for fisheries industries in the future.
2017, 39(10): 46-53.
doi: 10.3969/j.issn.0253-4193.2017.10.004
Abstract:
According to the 168 samples of Cololabis saira on June and during October to November in 2014 collected in the northwest Pacific Ocean. Age, hatch date and growth were obtained from statolith microstructure and combined with biological data. From the core to the transparent area edge, statolith increment width was from wide to narrow, brightness was from dark to bright, mark increment distributed in the transparent area. The range of age was from 204 d to 549 d, the dominant age was from 231 d to 290 d and 381 d to 470 d. The minimum age was 204 d, its body length and body weight was 207 mm and 39 g. The maximum age was 549 d, its body length and body weight was 291 mm and 131 g. The hatch date was December 2012 to April 2014, peak hatching dates were distributed in the months of January to March and August to October. Spawning groups was observed in spring and autumn spawning groups. The body length and weight growth model was suitable for Logistic growth model. Mean absolute daily growth rate (AGR) and instantaneous relative growth rate (G) of body length respectively was 0.224 mm/d and 0.000 88, AGR decreased with age increasing. Mean AGR and G of body weight respectively was 0.293mm/dand 0.003 25, the maximum AGR(0.504 mm/d) and G(0.004 86) appeared 351 d to 400 d.
According to the 168 samples of Cololabis saira on June and during October to November in 2014 collected in the northwest Pacific Ocean. Age, hatch date and growth were obtained from statolith microstructure and combined with biological data. From the core to the transparent area edge, statolith increment width was from wide to narrow, brightness was from dark to bright, mark increment distributed in the transparent area. The range of age was from 204 d to 549 d, the dominant age was from 231 d to 290 d and 381 d to 470 d. The minimum age was 204 d, its body length and body weight was 207 mm and 39 g. The maximum age was 549 d, its body length and body weight was 291 mm and 131 g. The hatch date was December 2012 to April 2014, peak hatching dates were distributed in the months of January to March and August to October. Spawning groups was observed in spring and autumn spawning groups. The body length and weight growth model was suitable for Logistic growth model. Mean absolute daily growth rate (AGR) and instantaneous relative growth rate (G) of body length respectively was 0.224 mm/d and 0.000 88, AGR decreased with age increasing. Mean AGR and G of body weight respectively was 0.293mm/dand 0.003 25, the maximum AGR(0.504 mm/d) and G(0.004 86) appeared 351 d to 400 d.
2017, 39(10): 54-64.
doi: 10.3969/j.issn.0253-4193.2017.10.005
Abstract:
This study was to understand the effects of artificial reef on the ecological restoration according to the investigation of marine biological resources around the artificial reef areas in the northern Yellow Sea from March 2013 to January 2014. Results showed that 55 zooplankton species occurred in the four seasons in this area, and the larvae of benthic species and planktonic copepods were the two dominant groups, in which the former one was the seasonal species in summer and autumn while the latter was dominant all the time. 14 species of nekton was found in this domain, dominated by reef fish. 12 benthic species were also found, in which the Diomedea albatrus was the dominant one, but it was the main predatory organism in the nearshore aquaculture. As the fishery resources in benthos, shrimps, crabs, and mollusc were presented as dominant species. The comparison between artificial reef areas and control areas showed that there were more species in the artificial reef areas. According to our results, the artificial reefs served for the ecological restoration and improved the biological diversity in these areas. To improve the primary production in the artificial reef area, the seaweed and large alga proliferation should be enhanced according to our investigation.
This study was to understand the effects of artificial reef on the ecological restoration according to the investigation of marine biological resources around the artificial reef areas in the northern Yellow Sea from March 2013 to January 2014. Results showed that 55 zooplankton species occurred in the four seasons in this area, and the larvae of benthic species and planktonic copepods were the two dominant groups, in which the former one was the seasonal species in summer and autumn while the latter was dominant all the time. 14 species of nekton was found in this domain, dominated by reef fish. 12 benthic species were also found, in which the Diomedea albatrus was the dominant one, but it was the main predatory organism in the nearshore aquaculture. As the fishery resources in benthos, shrimps, crabs, and mollusc were presented as dominant species. The comparison between artificial reef areas and control areas showed that there were more species in the artificial reef areas. According to our results, the artificial reefs served for the ecological restoration and improved the biological diversity in these areas. To improve the primary production in the artificial reef area, the seaweed and large alga proliferation should be enhanced according to our investigation.
2017, 39(10): 65-77.
doi: 10.3969/j.issn.0253-4193.2017.10.006
Abstract:
Based on the data obtained via the marine biological resources surveys of the Nanji Islands ground shallow sea area waters in November, 2013 and in February, May and September,2014, characteristics of crabs community including species composition, dominant species and biodiversity, were analyzed, and the related environmental factors were also examined. A total of 21 species, belonging to 12 genera in 7 families, were identified. The dominant species are Portunus trituberculatus, Charybdis bimaculataand Charybdis bimaculata. The species composition rather than dominant species showed clear seasonal changes. The maximum and minimum number of crab species were found in autumn and winter, respectively. The distribution of caught fisheries resources along water depths was documented that the morespecies were found at depths of 20-30 m and less species were found at depth of 30-40 m. The Shannon-Weaver diversity index of community in summer were lower than other seasons, and along water depths decreased from 10-20 m to 30-40 m, which means the Shannon-Weaver diversity index of crab community was in inverse proportion of the depth. Further redundancy analysis showed that water depth, temperature and salinity were the main environmental factors influencing crab species composition and community structure in this coastal conservation area.
Based on the data obtained via the marine biological resources surveys of the Nanji Islands ground shallow sea area waters in November, 2013 and in February, May and September,2014, characteristics of crabs community including species composition, dominant species and biodiversity, were analyzed, and the related environmental factors were also examined. A total of 21 species, belonging to 12 genera in 7 families, were identified. The dominant species are Portunus trituberculatus, Charybdis bimaculataand Charybdis bimaculata. The species composition rather than dominant species showed clear seasonal changes. The maximum and minimum number of crab species were found in autumn and winter, respectively. The distribution of caught fisheries resources along water depths was documented that the morespecies were found at depths of 20-30 m and less species were found at depth of 30-40 m. The Shannon-Weaver diversity index of community in summer were lower than other seasons, and along water depths decreased from 10-20 m to 30-40 m, which means the Shannon-Weaver diversity index of crab community was in inverse proportion of the depth. Further redundancy analysis showed that water depth, temperature and salinity were the main environmental factors influencing crab species composition and community structure in this coastal conservation area.
2017, 39(10): 78-89.
doi: 10.3969/j.issn.0253-4193.2017.10.007
Abstract:
The benthic meiofauna was quantitatively investigated in the Liaohe Estuary in August (summer) in 2013, October (autumn) in 2013 and May (spring) in 2014, and its spatial distribution and season variation were studied. The mean abundance of the meiofauna in summer, autumn and spring was (264±83) ind/(10 cm2), (216±85) ind/(10 cm2) and (227±67) ind/(10 cm2), respectively, and the mean biomass was (272±125) μg/(10 cm2), (207±89) μg/(10 cm2) and (244±103) μg/(10 cm2), respectively. Compared with other studied areas, the abundance and biomass of meiofauna in Liaohe Estuary were at a low level. A total of 14 meiofauna groups were identified. Free-living marine nematodes were the most dominant group in abundance, with the dominance of 94%, 92.5% and 90.8% in summer, autumn and spring, respectively, followed by polychaetes, benthic copepods and bivalves. In terms of biomass, the dominant groups were polychaetes (41.1%-44.0%), nematodes (33.8%-36.5%) and bivalves (2.6%-6.7%). The study of horizontal distribution showed that the abundance and biomass of the benthic meiofauna in inshore water were generally lower than those in offshore water, except autumn. The study of vertical distribution showed that 95.9% of the meiofauna distributed in the top 0-5 cm sediment. The abundance and biomass of the benthic meiofauna both reached their peak in summer. The correlation analysis indicated that the abundance of meiobenthos high significantly correlated with depth and salinity (P<0.01), and significantly correlated with Chl a(P<0.05).
The benthic meiofauna was quantitatively investigated in the Liaohe Estuary in August (summer) in 2013, October (autumn) in 2013 and May (spring) in 2014, and its spatial distribution and season variation were studied. The mean abundance of the meiofauna in summer, autumn and spring was (264±83) ind/(10 cm2), (216±85) ind/(10 cm2) and (227±67) ind/(10 cm2), respectively, and the mean biomass was (272±125) μg/(10 cm2), (207±89) μg/(10 cm2) and (244±103) μg/(10 cm2), respectively. Compared with other studied areas, the abundance and biomass of meiofauna in Liaohe Estuary were at a low level. A total of 14 meiofauna groups were identified. Free-living marine nematodes were the most dominant group in abundance, with the dominance of 94%, 92.5% and 90.8% in summer, autumn and spring, respectively, followed by polychaetes, benthic copepods and bivalves. In terms of biomass, the dominant groups were polychaetes (41.1%-44.0%), nematodes (33.8%-36.5%) and bivalves (2.6%-6.7%). The study of horizontal distribution showed that the abundance and biomass of the benthic meiofauna in inshore water were generally lower than those in offshore water, except autumn. The study of vertical distribution showed that 95.9% of the meiofauna distributed in the top 0-5 cm sediment. The abundance and biomass of the benthic meiofauna both reached their peak in summer. The correlation analysis indicated that the abundance of meiobenthos high significantly correlated with depth and salinity (P<0.01), and significantly correlated with Chl a(P<0.05).
2017, 39(10): 90-100.
doi: 10.3969/j.issn.0253-4193.2017.10.008
Abstract:
We studied the genetic diversity and population genetic variation of Bugula neritina,an important pharmaceutical organism,sampled from 4 distinct localities along China coastline by mitochondrial control region amplification and SLAF-seq. 8 haplotypes were detected in control region, haplotype diversity (h) and nucleotide diversity (π) were 0.130 7 and 0.000 7, respectively. No significant topological structure was found in haplotype network and NJ phylogenetic tree. Neutrality tests and mismatch distribution both suggested that B. neritina did not experience a range expansion. Fst and AMOVA analysis indicated that genetic variation mainly occurred within populations. SLAF library construction generated 214 409 SLAFs, among which 23 437 were polymorphic, 99 432 SNP loci were developed. Genetic distances among populations were short and even shorter than those within populations. Phylogenetic tree and population genetic analysis based on SNP data revealed that no significant genetic structure were observed among populations. In conclusion, genetic diversity of B. neritina in coastal waters of China were low, and no significant genetic structure existed among geographically distinct populations. We assumed this was mainly attributed to bryozoan's capability to disperse. In addition, our study validated the application and advantages of SLAF-seq in population genetic variation study of marine organisms.
We studied the genetic diversity and population genetic variation of Bugula neritina,an important pharmaceutical organism,sampled from 4 distinct localities along China coastline by mitochondrial control region amplification and SLAF-seq. 8 haplotypes were detected in control region, haplotype diversity (h) and nucleotide diversity (π) were 0.130 7 and 0.000 7, respectively. No significant topological structure was found in haplotype network and NJ phylogenetic tree. Neutrality tests and mismatch distribution both suggested that B. neritina did not experience a range expansion. Fst and AMOVA analysis indicated that genetic variation mainly occurred within populations. SLAF library construction generated 214 409 SLAFs, among which 23 437 were polymorphic, 99 432 SNP loci were developed. Genetic distances among populations were short and even shorter than those within populations. Phylogenetic tree and population genetic analysis based on SNP data revealed that no significant genetic structure were observed among populations. In conclusion, genetic diversity of B. neritina in coastal waters of China were low, and no significant genetic structure existed among geographically distinct populations. We assumed this was mainly attributed to bryozoan's capability to disperse. In addition, our study validated the application and advantages of SLAF-seq in population genetic variation study of marine organisms.
2017, 39(10): 101-110.
doi: 10.3969/j.issn.0253-4193.2017.10.009
Abstract:
For lack of temporal and spatial pattern of phytoplankton community structure in the Yellow Sea during the Holocene, biomarker records in core C02 and N05 were used to reconstruct the phytoplankton community structures, combined with published biomarker records. In the early Holocene, the relative ratios of alkenones (A/∑PB) and brassicasterol (B/∑PB) were low,while the relative ratio of dinosterol (D/∑PB) was high. High value of TMBR' index indicates that the phytoplankton community structure was controlled by terrestrial nutrients during this period. In the mid Holocene, A/∑PB increased, while B/∑PB and D/∑PB decreased. This is attributed to the Yellow Sea Warm Current intrusion with high temperature and high salinity. A/∑PB increased significantly at core sites ZY3, ZY2, ZY1 and YE-2 (35.5°N zone), while slightly at core sites C02 and N05. The Yellow Sea Warm Current flowed through the 35.5°N zone, controlling the phytoplankton community structure in the zone. However, the phytoplankton community structure in site C02 and N05 was still controlled by terrestrial nutrients. From the early Holocene to the mid Holocene, maximum of B/∑PB (D/∑PB) switched between sites C02 and N05 due to different controlling factors for these two locations, likely related to variations of the Yellow Sea Warm Current axis and the transportation of terrestrial matter. In the late Holocene, A/∑PB continued to increase, while B/∑PB and D/∑PB decreased. This might result from the strengthened circulation system induced by strengthened East Asian Winter Monsoon. Ratio between dinosterol and brassicasterol (D/B) increased in the late Holocene, due to the strengthened East Asian Winter Monsoon, which brought more nitrogen from atmosphere to ocean thus triggering dinoflagellates growth.
For lack of temporal and spatial pattern of phytoplankton community structure in the Yellow Sea during the Holocene, biomarker records in core C02 and N05 were used to reconstruct the phytoplankton community structures, combined with published biomarker records. In the early Holocene, the relative ratios of alkenones (A/∑PB) and brassicasterol (B/∑PB) were low,while the relative ratio of dinosterol (D/∑PB) was high. High value of TMBR' index indicates that the phytoplankton community structure was controlled by terrestrial nutrients during this period. In the mid Holocene, A/∑PB increased, while B/∑PB and D/∑PB decreased. This is attributed to the Yellow Sea Warm Current intrusion with high temperature and high salinity. A/∑PB increased significantly at core sites ZY3, ZY2, ZY1 and YE-2 (35.5°N zone), while slightly at core sites C02 and N05. The Yellow Sea Warm Current flowed through the 35.5°N zone, controlling the phytoplankton community structure in the zone. However, the phytoplankton community structure in site C02 and N05 was still controlled by terrestrial nutrients. From the early Holocene to the mid Holocene, maximum of B/∑PB (D/∑PB) switched between sites C02 and N05 due to different controlling factors for these two locations, likely related to variations of the Yellow Sea Warm Current axis and the transportation of terrestrial matter. In the late Holocene, A/∑PB continued to increase, while B/∑PB and D/∑PB decreased. This might result from the strengthened circulation system induced by strengthened East Asian Winter Monsoon. Ratio between dinosterol and brassicasterol (D/B) increased in the late Holocene, due to the strengthened East Asian Winter Monsoon, which brought more nitrogen from atmosphere to ocean thus triggering dinoflagellates growth.
2017, 39(10): 111-123.
doi: 10.3969/j.issn.0253-4193.2017.10.010
Abstract:
The composition and distribution of phytoplankton community were investigated during spring in 2016. Phytoplankton samples were analyzed by RP-HPLC combined with DAD (diode array detector) to determine photosynthetic pigments composition in the study area. Pigments data were converted into phytoplankton composition by software CHEMTAX based on least square method and steepest descent algorithm. Our results showed that chlorophyll b(Chl b), fucoxanthin were the major pigments in the Nanliu River Estuary. Cryptomonas dominated in the phytoplankton community, contributing to 54.95% of the phytoplankton biomass during spring in the Nanliu River Estuary, followed by chlorophytes and diatoms with 23.36% and 17.37%, respectively. The rest of other phytoplankton was rare, which only took less than 10% of all phytoplankton biomass. There were vary greatly in the composition of phytoplankton community between eastern and western branch of Nanliu River. In eastern branch, the nitrate of was lower than western, and cryptomonas dominated in the phytoplankton community, followed by chlorophytes and diatoms, nitrate was the main influence factors to the composition and distribution of phytoplankton community. In western branch, the proportion of chlorophytes and diatoms increased, non-nitrate factor was the main influence factors to the phytoplankton community. Except nitrate, the western phytoplankton community also influenced by turbidity and salinity. The results indicate that turbidity significant influence the structure and function of ecological system.
The composition and distribution of phytoplankton community were investigated during spring in 2016. Phytoplankton samples were analyzed by RP-HPLC combined with DAD (diode array detector) to determine photosynthetic pigments composition in the study area. Pigments data were converted into phytoplankton composition by software CHEMTAX based on least square method and steepest descent algorithm. Our results showed that chlorophyll b(Chl b), fucoxanthin were the major pigments in the Nanliu River Estuary. Cryptomonas dominated in the phytoplankton community, contributing to 54.95% of the phytoplankton biomass during spring in the Nanliu River Estuary, followed by chlorophytes and diatoms with 23.36% and 17.37%, respectively. The rest of other phytoplankton was rare, which only took less than 10% of all phytoplankton biomass. There were vary greatly in the composition of phytoplankton community between eastern and western branch of Nanliu River. In eastern branch, the nitrate of was lower than western, and cryptomonas dominated in the phytoplankton community, followed by chlorophytes and diatoms, nitrate was the main influence factors to the composition and distribution of phytoplankton community. In western branch, the proportion of chlorophytes and diatoms increased, non-nitrate factor was the main influence factors to the phytoplankton community. Except nitrate, the western phytoplankton community also influenced by turbidity and salinity. The results indicate that turbidity significant influence the structure and function of ecological system.
2017, 39(10): 124-144.
doi: 10.3969/j.issn.0253-4193.2017.10.011
Abstract:
Based on the multi-discipline surveys in the Changjiang (Yangtze) River Estuary and its adjacent waters in March and August 2013, the phytoplankton species composition and community structure was studied, and its correlations with major environment factors were analyzed as well. During the dry season, 80 taxa belonging to 41 genera and 3 phyla were identified. Paralia sulcate was the most dominant specie. The cell abundance ranged from 0.15×103 cells/L to 16.35×103 cells/L, with an average of (3.24±3.14)×103 cells/L. The horizontal distribution of cell abundance was mainly dominated by diatom, with high values appeared in the north of the survey area and lower in the coastal waters. During the wet season, 135 taxa belonging to 67 genera and 4 phyla were identified, the main dominant species were Prorocentrum donghaiense and Skeletonema sp.. The cell abundance ranging from 0.2×103 cells/L to 1 925.45×103 cells/L, with an average of (41.67±186.00)×103 cells/L, was higher in the north of the survey area as well as in the southeast area close to the coast, dominated by dinoflagellate. The salinity and turbidity influenced the phytoplankton assemblage during the survey. The N/P ratio, instead of Si/N ratio, played a significant role in regulating the phytoplankton community structure. With the increase of N/P ratio, the diatom became dominant in the phytoplankton assemblage. Proliferation of phytoplankton in the upper layer and stratification of water column were necessary for the formation of hypoxia. Diatom-dominant community had higher sinking rate than dinoflagelate-dominant community, thus in favor of the consuming of dissolved oxygen in the bottom waters.
Based on the multi-discipline surveys in the Changjiang (Yangtze) River Estuary and its adjacent waters in March and August 2013, the phytoplankton species composition and community structure was studied, and its correlations with major environment factors were analyzed as well. During the dry season, 80 taxa belonging to 41 genera and 3 phyla were identified. Paralia sulcate was the most dominant specie. The cell abundance ranged from 0.15×103 cells/L to 16.35×103 cells/L, with an average of (3.24±3.14)×103 cells/L. The horizontal distribution of cell abundance was mainly dominated by diatom, with high values appeared in the north of the survey area and lower in the coastal waters. During the wet season, 135 taxa belonging to 67 genera and 4 phyla were identified, the main dominant species were Prorocentrum donghaiense and Skeletonema sp.. The cell abundance ranging from 0.2×103 cells/L to 1 925.45×103 cells/L, with an average of (41.67±186.00)×103 cells/L, was higher in the north of the survey area as well as in the southeast area close to the coast, dominated by dinoflagellate. The salinity and turbidity influenced the phytoplankton assemblage during the survey. The N/P ratio, instead of Si/N ratio, played a significant role in regulating the phytoplankton community structure. With the increase of N/P ratio, the diatom became dominant in the phytoplankton assemblage. Proliferation of phytoplankton in the upper layer and stratification of water column were necessary for the formation of hypoxia. Diatom-dominant community had higher sinking rate than dinoflagelate-dominant community, thus in favor of the consuming of dissolved oxygen in the bottom waters.
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