2014 Vol. 33, No. 8
Display Method:
2014, 33(8): .
Abstract:
2014, 33(8): 1-9.
doi: 10.1007/s13131-014-0407-8
Abstract:
High-resolution Chirp profiling and coring reveals an elongated (ca. 400 km) Holocene Zhujiang River (Pearl River)-derived mud area (maximum thickness>20 m) extending from the Zhujiang River Delta, southwestward off the Guangdong coast, to the Leizhou Peninsula. Two depo-centers, one proximal and one distal, are identified. On the continental shelf off the west Guangdong Province, the mud is deposited in water depth shallower than 50 m; while to the southeast of the Zhujiang River Estuary, the mud area can extend to the -120 m isobath. A combined analysis with the stratigraphic sequences of other muddy deposits in the Western Pacific marginal seas (mainly Changjiang (Yangtze) and Huanghe (Yellow) Rivers derived) indicates that the initiation of the Zhujiang River muddy deposit can be further divided into two stages: Stage 1 is before the mid-Holocene sea-level highstand (ca. 7.0 cal. ka BP), the proximal mud was mostly deposited after 9.0 cal. ka BP, when the sea-level rose slowly after the Meltwater Pulse -1C; Stage 2, after the mid-Holocene sealevel highstand, clinoform developed on the continental shelf off the west Guangdong Province, extending ca. 400 km from the Zhujiang River Estuary. The proximal clinoform thins offshore, from ca. 10 m thickness around 5-10 m water depth to less than 1-2 m around 20-30 m water depth. In addition, we also find a developed distal clinoform in the east of the Leizhou Peninsula.
High-resolution Chirp profiling and coring reveals an elongated (ca. 400 km) Holocene Zhujiang River (Pearl River)-derived mud area (maximum thickness>20 m) extending from the Zhujiang River Delta, southwestward off the Guangdong coast, to the Leizhou Peninsula. Two depo-centers, one proximal and one distal, are identified. On the continental shelf off the west Guangdong Province, the mud is deposited in water depth shallower than 50 m; while to the southeast of the Zhujiang River Estuary, the mud area can extend to the -120 m isobath. A combined analysis with the stratigraphic sequences of other muddy deposits in the Western Pacific marginal seas (mainly Changjiang (Yangtze) and Huanghe (Yellow) Rivers derived) indicates that the initiation of the Zhujiang River muddy deposit can be further divided into two stages: Stage 1 is before the mid-Holocene sea-level highstand (ca. 7.0 cal. ka BP), the proximal mud was mostly deposited after 9.0 cal. ka BP, when the sea-level rose slowly after the Meltwater Pulse -1C; Stage 2, after the mid-Holocene sealevel highstand, clinoform developed on the continental shelf off the west Guangdong Province, extending ca. 400 km from the Zhujiang River Estuary. The proximal clinoform thins offshore, from ca. 10 m thickness around 5-10 m water depth to less than 1-2 m around 20-30 m water depth. In addition, we also find a developed distal clinoform in the east of the Leizhou Peninsula.
2014, 33(8): 10-17.
doi: 10.1007/s13131-014-0458-x
Abstract:
Subtropical sediment cores (QA09-1 and QA12-9) from the coastal zone of Qi'ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental temperature changes. The depth distribution of the sulfate reduction rates was measured from whole-core incubations with radioactive tracer 35SO42-, and peaks of 181.19 nmol/(cm3·d) and 107.49 nmol/(cm3·d) were exhibited at stations QA09-1 and QA12-9, respectively. The profiles of the pore water methane and sulfate concentrations demonstrated that anaerobic oxidation of methane occurred in the study area, which resulted in an increase in the sulfate reduction rate at the base of the sulfate-reducing zone. Meanwhile, the sulfate concentration was not a major limiting factor for controlling the rates of sulfate reduction. In addition, the incubation of the sediment slurries in a block with a temperature gradient showed that the optimum temperature for the sulfate reduction reaction was 36℃. The Arrhenius plot was linear from the lowest temperature to the optimum temperature, and the activation energy was at the lower end of the range of previously reported values. The results suggested that the ambient temperature regime of marine environments probably selected for the microbial population with the best-suited physiology for the respective environment.
Subtropical sediment cores (QA09-1 and QA12-9) from the coastal zone of Qi'ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental temperature changes. The depth distribution of the sulfate reduction rates was measured from whole-core incubations with radioactive tracer 35SO42-, and peaks of 181.19 nmol/(cm3·d) and 107.49 nmol/(cm3·d) were exhibited at stations QA09-1 and QA12-9, respectively. The profiles of the pore water methane and sulfate concentrations demonstrated that anaerobic oxidation of methane occurred in the study area, which resulted in an increase in the sulfate reduction rate at the base of the sulfate-reducing zone. Meanwhile, the sulfate concentration was not a major limiting factor for controlling the rates of sulfate reduction. In addition, the incubation of the sediment slurries in a block with a temperature gradient showed that the optimum temperature for the sulfate reduction reaction was 36℃. The Arrhenius plot was linear from the lowest temperature to the optimum temperature, and the activation energy was at the lower end of the range of previously reported values. The results suggested that the ambient temperature regime of marine environments probably selected for the microbial population with the best-suited physiology for the respective environment.
2014, 33(8): 18-25.
doi: 10.1007/s13131-014-0399-4
Abstract:
Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a 14C dated (AD 990±40) fossil giant clam, Tridacna gigas, from Shidao Island, South China Sea. The δ18O profile of the T. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with the δ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of the Tridacna specimen was stable after the onset of sexual maturity. Spectral analysis of the δ18O and blue color intensity time series suggested that the El Niño-Southern Oscillation (ENSO) period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.
Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a 14C dated (AD 990±40) fossil giant clam, Tridacna gigas, from Shidao Island, South China Sea. The δ18O profile of the T. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with the δ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of the Tridacna specimen was stable after the onset of sexual maturity. Spectral analysis of the δ18O and blue color intensity time series suggested that the El Niño-Southern Oscillation (ENSO) period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.
2014, 33(8): 26-33.
doi: 10.1007/s13131-014-0461-2
Abstract:
Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic compositions, like that of He, Ne and Ar, can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type crusts have low 84Kr and 132Xe abundance, while the high 3He/4He type crusts have high 84Kr and 132Xe abundance. The 82Kr/84Kr ratios of the low 3He/4He type crusts are lower than that of the air, while the 83Kr/84Kr and 86Kr/84Kr ratios are higher than those of the air. The Kr isotopic ratios of the higher 3He/4He type crusts are quite similar to those of the air. The 128Xe/132Xe, 130Xe/132Xe and 131Xe/132Xe ratios of the low 3He/4He type sample are distinctly lower than those of the air, whereas the 129Xe/132Xe, 134Xe/132Xe and 136Xe/132Xe ratios are higher than those of the air. The low 3He/4He type samples have the diagnostic characteristics of the MORB, with excess 129,131,132,134,136Xe relative to 130Xe compared with the solar wind. The 128Xe/132Xe, 130Xe/132Xe and 131Xe/132Xe ratios of the high 3He/4He type samples are slightly higher than those of the air, and the 129Xe/132Xe, 134Xe/132Xe and 136Xe/132Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ratios of the low mantle reservoir are predominantly controlled by primitive He (3He) and U and Th radiogenic decayed He (4He), but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high 3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low 3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.
Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic compositions, like that of He, Ne and Ar, can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type crusts have low 84Kr and 132Xe abundance, while the high 3He/4He type crusts have high 84Kr and 132Xe abundance. The 82Kr/84Kr ratios of the low 3He/4He type crusts are lower than that of the air, while the 83Kr/84Kr and 86Kr/84Kr ratios are higher than those of the air. The Kr isotopic ratios of the higher 3He/4He type crusts are quite similar to those of the air. The 128Xe/132Xe, 130Xe/132Xe and 131Xe/132Xe ratios of the low 3He/4He type sample are distinctly lower than those of the air, whereas the 129Xe/132Xe, 134Xe/132Xe and 136Xe/132Xe ratios are higher than those of the air. The low 3He/4He type samples have the diagnostic characteristics of the MORB, with excess 129,131,132,134,136Xe relative to 130Xe compared with the solar wind. The 128Xe/132Xe, 130Xe/132Xe and 131Xe/132Xe ratios of the high 3He/4He type samples are slightly higher than those of the air, and the 129Xe/132Xe, 134Xe/132Xe and 136Xe/132Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ratios of the low mantle reservoir are predominantly controlled by primitive He (3He) and U and Th radiogenic decayed He (4He), but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high 3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low 3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.
2014, 33(8): 34-43.
doi: 10.1007/s13131-014-0406-9
Abstract:
Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders (MAPR) attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/V Dayang I in the "Precious Stone Mountain" hydrothermal field on the Galapagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activity in this field, indicating the presence of a new hydrothermal vent.
Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders (MAPR) attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/V Dayang I in the "Precious Stone Mountain" hydrothermal field on the Galapagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activity in this field, indicating the presence of a new hydrothermal vent.
2014, 33(8): 44-54.
doi: 10.1007/s13131-014-0457-y
Abstract:
The so-called zebra sole includes a group of small flatfishes characterized by transverse band pairs on the ocular side and distributed throughout shallow waters along the coast of the Indo-West Pacific Ocean. Several species of the zebra sole have been recorded from the coastal waters of China. Morphological analysis of 1107 specimens of the zebra sole from 15 successive localities along the China's coast demonstrated that no significant variations among these localities were found on the basis of meristic counts and morphometric characters. Phylogenetic analysis based on COI gene sequences of 14 individuals and D-loop of 22 individuals from eight localities showed that they were indistinguishable among these localities. Therefore, both morphological and molecular evidence supported the occurrence of a single species of the zebra sole along the China's coast. The available name for this species is Zebrias zebrinus (Temminck and Schlegel, 1846) instead of Z. zebra (Bloch, 1787). Zebrias fasciatus (Basilewsky, 1855) and Solea ommatura (Richardson, 1846) are considered here as two synonyms of Z. zebrinus.
The so-called zebra sole includes a group of small flatfishes characterized by transverse band pairs on the ocular side and distributed throughout shallow waters along the coast of the Indo-West Pacific Ocean. Several species of the zebra sole have been recorded from the coastal waters of China. Morphological analysis of 1107 specimens of the zebra sole from 15 successive localities along the China's coast demonstrated that no significant variations among these localities were found on the basis of meristic counts and morphometric characters. Phylogenetic analysis based on COI gene sequences of 14 individuals and D-loop of 22 individuals from eight localities showed that they were indistinguishable among these localities. Therefore, both morphological and molecular evidence supported the occurrence of a single species of the zebra sole along the China's coast. The available name for this species is Zebrias zebrinus (Temminck and Schlegel, 1846) instead of Z. zebra (Bloch, 1787). Zebrias fasciatus (Basilewsky, 1855) and Solea ommatura (Richardson, 1846) are considered here as two synonyms of Z. zebrinus.
Comparative analysis of transcriptomes from albino and control sea cucumbers, Apostichopus japonicus
2014, 33(8): 55-61.
doi: 10.1007/s13131-014-0464-z
Abstract:
The sea cucumber Apostichopus japonicus is an important economic species in China. Its dorsal body wall color is commonly tawny, whereas its ventral surface is fawn. Albino sea cucumbers are rarely observed. In order to profile gene expression and screen albinism-related genes, we compared the transcriptome of albino samples with a control by 454 cDNA sequencing. We found that 6539 identified genes on the basis of sequence similarity to known genes were expressed in the albino A. japonicus. The gene ontology analysis indicated that the transcription of genes associated with the terms of biological regulation and pigmentation was non-abundant in the albino library compared to the control. Based on an analysis using the Kyoto Encyclopedia of Genes and Genomics (KEGG) database, we identified 14 important genes that were involved in major intercellular signaling pathways related to melanin synthesis, such as tyrosine metabolism, the mitogen-activated protein kinase (MAPK) pathway, and melanogenesis. The expressions of fibroblast growth factor receptor 4 (FGFR4), protein kinase C (PKC), protein kinase A (PKA), and Ras genes were significantly down-regulated in the albino transcriptome compared with the control, while the expressions of homogentisate 1, 2-dioxygenase gene (HGO), cAMP-responsive element binding protein (CREB), transcription factor AP-1(c-jun), and calmodulin (CaM) were significantly up-regulated (Fisher's exact test, p < 0.05). These differentially expressed genes could be candidate genes for revealing the mechanism of albinism and investigating regulation of melanin synthesis in A. japonicus.
The sea cucumber Apostichopus japonicus is an important economic species in China. Its dorsal body wall color is commonly tawny, whereas its ventral surface is fawn. Albino sea cucumbers are rarely observed. In order to profile gene expression and screen albinism-related genes, we compared the transcriptome of albino samples with a control by 454 cDNA sequencing. We found that 6539 identified genes on the basis of sequence similarity to known genes were expressed in the albino A. japonicus. The gene ontology analysis indicated that the transcription of genes associated with the terms of biological regulation and pigmentation was non-abundant in the albino library compared to the control. Based on an analysis using the Kyoto Encyclopedia of Genes and Genomics (KEGG) database, we identified 14 important genes that were involved in major intercellular signaling pathways related to melanin synthesis, such as tyrosine metabolism, the mitogen-activated protein kinase (MAPK) pathway, and melanogenesis. The expressions of fibroblast growth factor receptor 4 (FGFR4), protein kinase C (PKC), protein kinase A (PKA), and Ras genes were significantly down-regulated in the albino transcriptome compared with the control, while the expressions of homogentisate 1, 2-dioxygenase gene (HGO), cAMP-responsive element binding protein (CREB), transcription factor AP-1(c-jun), and calmodulin (CaM) were significantly up-regulated (Fisher's exact test, p < 0.05). These differentially expressed genes could be candidate genes for revealing the mechanism of albinism and investigating regulation of melanin synthesis in A. japonicus.
2014, 33(8): 62-72.
doi: 10.1007/s13131-014-0454-1
Abstract:
The Sonneratia apetala artificial mangroves in the intertidal zone of Da Wei Bay at Qi'ao Island of Zhuhai, South China were chosen as the macrofauna succession plots while bare tidal flats of the same size were established as control plots in surrounding interference-free areas. Conventional change indicators of community structure, such as biomass and biodiversity, and indicators, such as exergy and specific exergy, which reflect the information change of overall communities, were used to analyze the succession of macrofauna communities in S. apetala artificial mangroves. The similarities and differences in variation tendency of the different ecological indicators and their reflected ecological principles were compared. The results showed that from D-1 to D-1275 after planting S. apetala, the biomass of the macrofauna communities first increased, which was then followed by an increase in the network relationship between the macrofauna communities (analysis of the Pielou evenness index and Shannon-Wiener diversity index). The system information (specific exergy) increased the slowest. Between D-1460 and D-2370 after planting S. apetala, there was a decrease in biomass, network structure, and system information in the succession plots. After the decrease in the system information (the specific exergy), there was a decline in the network relationships (Pielou evenness index and Shannon-Wiener diversity index). Biomass was the last indicator to decrease. The similarities and differences among the different ecological indicators varied during the succession process, which reflected the relativity and differences among the indicators. This study suggested that, although the species diversity index can be an effective indicator of two types of changes (network structure and system information), it was quite clear that species diversity measurement was not suitable for expressing the changes in biomass during the succession process. While exergy and specific exergy can provide useful information about the structural development of communities, they cannot identify the information state of the system. Therefore, when evaluating macrofaunal succession in S. apetala artificial mangrove wetlands, it would be better to apply a number of different ecological indicators, rather than just one single indicator.
The Sonneratia apetala artificial mangroves in the intertidal zone of Da Wei Bay at Qi'ao Island of Zhuhai, South China were chosen as the macrofauna succession plots while bare tidal flats of the same size were established as control plots in surrounding interference-free areas. Conventional change indicators of community structure, such as biomass and biodiversity, and indicators, such as exergy and specific exergy, which reflect the information change of overall communities, were used to analyze the succession of macrofauna communities in S. apetala artificial mangroves. The similarities and differences in variation tendency of the different ecological indicators and their reflected ecological principles were compared. The results showed that from D-1 to D-1275 after planting S. apetala, the biomass of the macrofauna communities first increased, which was then followed by an increase in the network relationship between the macrofauna communities (analysis of the Pielou evenness index and Shannon-Wiener diversity index). The system information (specific exergy) increased the slowest. Between D-1460 and D-2370 after planting S. apetala, there was a decrease in biomass, network structure, and system information in the succession plots. After the decrease in the system information (the specific exergy), there was a decline in the network relationships (Pielou evenness index and Shannon-Wiener diversity index). Biomass was the last indicator to decrease. The similarities and differences among the different ecological indicators varied during the succession process, which reflected the relativity and differences among the indicators. This study suggested that, although the species diversity index can be an effective indicator of two types of changes (network structure and system information), it was quite clear that species diversity measurement was not suitable for expressing the changes in biomass during the succession process. While exergy and specific exergy can provide useful information about the structural development of communities, they cannot identify the information state of the system. Therefore, when evaluating macrofaunal succession in S. apetala artificial mangrove wetlands, it would be better to apply a number of different ecological indicators, rather than just one single indicator.
2014, 33(8): 73-82.
doi: 10.1007/s13131-014-0414-9
Abstract:
The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types (Avicennia marina assemblage and Sonneratia apetala assemblage) in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assemblages, of which the dominant species were Cladophoropsis zollingeri and Enteromorpha clathrat. Macroalgal species were significantly most abundant in spring (p<0.05), followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove assemblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in the S. apetala assemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgae C. zollingeri, E. clathrata, and Gracilaria salicornia in the A. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.
The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types (Avicennia marina assemblage and Sonneratia apetala assemblage) in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assemblages, of which the dominant species were Cladophoropsis zollingeri and Enteromorpha clathrat. Macroalgal species were significantly most abundant in spring (p<0.05), followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove assemblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in the S. apetala assemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgae C. zollingeri, E. clathrata, and Gracilaria salicornia in the A. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.
2014, 33(8): 83-94.
doi: 10.1007/s13131-014-0481-y
Abstract:
An investigation was carried out on living coccolithophores (LCs) distribution in the Yellow Sea and the East China Sea from October 17 to November 24, 2011. A total of 223 samples from different depths were collected at 48 stations. Totally 18 taxa belonging to coccolithophyceae were identified using a polarized microscope at the 1000×magnification. The maximum species abundance was found at the outside of Transect P. The dominated species were Gephyrocapsa oceanica, Emiliania huxleyi, Helicosphaera carteri, and Algirosphaera robusta. The abundance of coccoliths and cells ranged 0-2965.73 coccoliths/mL, and 0-119.16 cells/ mL, with the average values of 471.00 coccoliths/mL and 23.42 cells/mL, respectively. The LCs in surface layer were mainly observed on the coastal belt and middle part of the survey area. The comparison among Transects A, F, P and E indicated lower species diversity and less abundance in the Yellow Sea than those of the East China Sea. The highest abundance of LCs was found in transect F and P. The coccolith abundance increased slightly from surface to bottom in the water column, but the highest value of the cell abundance was observed in the depth of 10-30 m. Temperature, depth and nutrient concentration were suggested as the major environmental factors controlling the distribution and species composition of LCs in the studying area based on canonical correspondence analysis (CCA).
An investigation was carried out on living coccolithophores (LCs) distribution in the Yellow Sea and the East China Sea from October 17 to November 24, 2011. A total of 223 samples from different depths were collected at 48 stations. Totally 18 taxa belonging to coccolithophyceae were identified using a polarized microscope at the 1000×magnification. The maximum species abundance was found at the outside of Transect P. The dominated species were Gephyrocapsa oceanica, Emiliania huxleyi, Helicosphaera carteri, and Algirosphaera robusta. The abundance of coccoliths and cells ranged 0-2965.73 coccoliths/mL, and 0-119.16 cells/ mL, with the average values of 471.00 coccoliths/mL and 23.42 cells/mL, respectively. The LCs in surface layer were mainly observed on the coastal belt and middle part of the survey area. The comparison among Transects A, F, P and E indicated lower species diversity and less abundance in the Yellow Sea than those of the East China Sea. The highest abundance of LCs was found in transect F and P. The coccolith abundance increased slightly from surface to bottom in the water column, but the highest value of the cell abundance was observed in the depth of 10-30 m. Temperature, depth and nutrient concentration were suggested as the major environmental factors controlling the distribution and species composition of LCs in the studying area based on canonical correspondence analysis (CCA).
2014, 33(8): 95-105.
doi: 10.1007/s13131-014-0459-9
Abstract:
Based on systematized physical, chemical, and biological modules, a multi-species harmful algal bloom (HAB) model coupled with background ecological fields was established. This model schematically embodied that HAB causative algal species and the background ecological system, quantified as total biomass, were significantly different in terms of the chemical and biological processes during a HAB while the interaction between the two was present. The model also included a competition and interaction mechanism between the HAB algal species or populations. The Droop equation was optimized by considering temperature, salinity, and suspended material impact factors in the parameterization of algal growth rate with the nutrient threshold. Two HAB processes in the springs of 2004 and 2005 were simulated using this model. Both simulation results showed consistent trends with corresponding HAB processes observed in the East China Sea, which indicated the rationality of the model. This study made certain progress in modeling HABs, which has great application potential for HAB diagnosis, prediction, and prevention.
Based on systematized physical, chemical, and biological modules, a multi-species harmful algal bloom (HAB) model coupled with background ecological fields was established. This model schematically embodied that HAB causative algal species and the background ecological system, quantified as total biomass, were significantly different in terms of the chemical and biological processes during a HAB while the interaction between the two was present. The model also included a competition and interaction mechanism between the HAB algal species or populations. The Droop equation was optimized by considering temperature, salinity, and suspended material impact factors in the parameterization of algal growth rate with the nutrient threshold. Two HAB processes in the springs of 2004 and 2005 were simulated using this model. Both simulation results showed consistent trends with corresponding HAB processes observed in the East China Sea, which indicated the rationality of the model. This study made certain progress in modeling HABs, which has great application potential for HAB diagnosis, prediction, and prevention.
2014, 33(8): 106-110.
doi: 10.1007/s13131-014-0460-3
Abstract:
Twenty-six half-sib groups (53 full-sib families) of turbot, Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring (40-50 individuals/family) and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mortality (range: 0.580%-1.391%) between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 (20.232% and 34.377%, respectively). Mortality was highest on Day 16 (14.145%). We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods (maximum log L). Lastly, we estimated phenotypic and genetic correlation between the upper thermal tolerance limit (UTT) and body weight (BW). In this study, the positive phenotypic correlation was low between UTT and BW (0.093±0.029). The genetic correlation between UTT and BW was negative (-0.044±0.239). The heritability for upper thermal tolerance was low (0.087±0.032), which is of approximately moderate heritability. The heritability for body weight was high (0.303±0.074). Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.
Twenty-six half-sib groups (53 full-sib families) of turbot, Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring (40-50 individuals/family) and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mortality (range: 0.580%-1.391%) between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 (20.232% and 34.377%, respectively). Mortality was highest on Day 16 (14.145%). We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods (maximum log L). Lastly, we estimated phenotypic and genetic correlation between the upper thermal tolerance limit (UTT) and body weight (BW). In this study, the positive phenotypic correlation was low between UTT and BW (0.093±0.029). The genetic correlation between UTT and BW was negative (-0.044±0.239). The heritability for upper thermal tolerance was low (0.087±0.032), which is of approximately moderate heritability. The heritability for body weight was high (0.303±0.074). Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.
2014, 33(8): 111-118.
doi: 10.1007/s13131-014-0465-y
Abstract:
Four species in the genus Navicula were isolated using the serial dilution method. Based on scanning electron microscopy (SEM) and sequence comparisons of two segments of genes (small ribosomal subunit and large subunit of Rubisco), the species were identified as Navicula perminuta, N. pseudacceptata, N. vara, and N. rhynchocephala. Based on phylogenetic analysis and culture trials, there was a close relationship between N. perminuta and N. vara. Growth of these species was evaluated using measurements of optical density at 680 nm (OD680) under various environmental factors. Results showed that the optimum culture conditions were 25℃, 50–100 μmol photons m-2 s-1, pH 8.0, and salinities from 25 to 30. However, the favorable salinity for N. perminuta was surprisingly high at 35. Nutrient requirement analysis demonstrated that growth of Navicula depended on the availability of SiO32-. Their relative growth rates (RGR) peaked at the highest tested level (0.25 mmol/L). The optimal concentrations of NO3- and PO43- were 3.6 mmol/L and 0.18 mmol/L, respectively. Culture of these Navicula species for abalone or sea cucumber aquaculture should take these factors into consideration.
Four species in the genus Navicula were isolated using the serial dilution method. Based on scanning electron microscopy (SEM) and sequence comparisons of two segments of genes (small ribosomal subunit and large subunit of Rubisco), the species were identified as Navicula perminuta, N. pseudacceptata, N. vara, and N. rhynchocephala. Based on phylogenetic analysis and culture trials, there was a close relationship between N. perminuta and N. vara. Growth of these species was evaluated using measurements of optical density at 680 nm (OD680) under various environmental factors. Results showed that the optimum culture conditions were 25℃, 50–100 μmol photons m-2 s-1, pH 8.0, and salinities from 25 to 30. However, the favorable salinity for N. perminuta was surprisingly high at 35. Nutrient requirement analysis demonstrated that growth of Navicula depended on the availability of SiO32-. Their relative growth rates (RGR) peaked at the highest tested level (0.25 mmol/L). The optimal concentrations of NO3- and PO43- were 3.6 mmol/L and 0.18 mmol/L, respectively. Culture of these Navicula species for abalone or sea cucumber aquaculture should take these factors into consideration.
