2008 Vol. 27, No. 2
column
Display Method:
2008, (2): 1-10.
Abstract:
Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them.Each mode has a pair of cyclonic-anticyclonic gyres.The difference is the location of the cyclonic gyre.The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode.The observed modes strongly affect the heat and salt transport in the North Atlantic.In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.
Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them.Each mode has a pair of cyclonic-anticyclonic gyres.The difference is the location of the cyclonic gyre.The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode.The observed modes strongly affect the heat and salt transport in the North Atlantic.In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.
2008, (2): 11-20.
Abstract:
Stokes drift is the main source of vertical vorticity in the ocean mixed layer.In the ways of Coriolis-Stokes forcing and Langmuir circulations, Stokes drift can substantially affect the whole mixed layer.A modified Mellor-Yamada 2.5 level turbulence closure model is used to parameterize its effect on upper ocean mixing conventionally.Results show that comparing surface heating with wave breaking, Stokes drift plays the most important role in the entire ocean mixed layer, especially in the subsurface layer.As expected, Stokes drift elevates both the dissipation rate and the turbulence energy in the upper ocean mixing.Also, influence of the surface heating, wave breaking and wind speed on Stokes drift is investigated respectively.Research shows that it is significant and important to assessing the Stokes drift into ocean mixed layer studying.The laboratory observations are supporting numerical experiments quantitatively.
Stokes drift is the main source of vertical vorticity in the ocean mixed layer.In the ways of Coriolis-Stokes forcing and Langmuir circulations, Stokes drift can substantially affect the whole mixed layer.A modified Mellor-Yamada 2.5 level turbulence closure model is used to parameterize its effect on upper ocean mixing conventionally.Results show that comparing surface heating with wave breaking, Stokes drift plays the most important role in the entire ocean mixed layer, especially in the subsurface layer.As expected, Stokes drift elevates both the dissipation rate and the turbulence energy in the upper ocean mixing.Also, influence of the surface heating, wave breaking and wind speed on Stokes drift is investigated respectively.Research shows that it is significant and important to assessing the Stokes drift into ocean mixed layer studying.The laboratory observations are supporting numerical experiments quantitatively.
2008, (2): 21-29.
Abstract:
Dissolved and particulate thorium-234, particulate organic carbon in the upper 150 m of water columns from five stations in the Prydz Bay, the Southern Ocean were determined during the 22nd Chinese National Antarctic Research Expedition (from November 2005 to March 2006).The disequilibria between thorium-234 and its parent uranium-238 in upper layer was used to derive the averaged residence time of thorium-234, which decreased along with the latitude to the south and a minimum value, 1~8 d for particulate thorium-234 and 29~48 d for dissolved thorium-234, appeared at the medium latitude station, and the export fluxes of thorium-234 were calculated too and a maximum value, 0.35~0.63 Bq/(m3·d) for the particulate thorium-234 and 0.44~0.65 Bq/(m3·d) for the dissolved thorium-234, appeared at the same station.The export fluxes of particulate organic carbon at different water columns were derived by two methods with irreversible scavenging model, and the averaged values were 104.7 mmol/(m2·d) (E method) and 120.6 mmol/(m2·d) (B method), respectively, indicating that a relatively high new production would exist in summer in the Prydz Bay where it will play a potential significant role in sequestering the absorption CO2 to deeper ocean.
Dissolved and particulate thorium-234, particulate organic carbon in the upper 150 m of water columns from five stations in the Prydz Bay, the Southern Ocean were determined during the 22nd Chinese National Antarctic Research Expedition (from November 2005 to March 2006).The disequilibria between thorium-234 and its parent uranium-238 in upper layer was used to derive the averaged residence time of thorium-234, which decreased along with the latitude to the south and a minimum value, 1~8 d for particulate thorium-234 and 29~48 d for dissolved thorium-234, appeared at the medium latitude station, and the export fluxes of thorium-234 were calculated too and a maximum value, 0.35~0.63 Bq/(m3·d) for the particulate thorium-234 and 0.44~0.65 Bq/(m3·d) for the dissolved thorium-234, appeared at the same station.The export fluxes of particulate organic carbon at different water columns were derived by two methods with irreversible scavenging model, and the averaged values were 104.7 mmol/(m2·d) (E method) and 120.6 mmol/(m2·d) (B method), respectively, indicating that a relatively high new production would exist in summer in the Prydz Bay where it will play a potential significant role in sequestering the absorption CO2 to deeper ocean.
2008, (2): 30-34.
Abstract:
Foraminiferal shells from two piston cores separately located at the Ninetyeast Ridge and the Bengal Fan of the Indian Ocean were selected and purified for measurements of natural thermoluminescence (NTL) intensity by a high precision thermoluminescence meter (RGD-3).Variations of the NTL intensity along the two core sequences both spanning the last two glacial-interglacial cycles displayed a strong, identical signal of the global ice volume cycles, which matched well with their corresponding oxygen isotope data.As higher NTL intensity occurred within interglacial periods and changes in an NTL signal were most likely influenced by the temperature of ambient seawater in which the planktonic foraminiferal shells long existed, the NTL signal could be considered as a potential proxy for orbital scale temperature changes of bottom seawater in the tropical Indian Ocean.
Foraminiferal shells from two piston cores separately located at the Ninetyeast Ridge and the Bengal Fan of the Indian Ocean were selected and purified for measurements of natural thermoluminescence (NTL) intensity by a high precision thermoluminescence meter (RGD-3).Variations of the NTL intensity along the two core sequences both spanning the last two glacial-interglacial cycles displayed a strong, identical signal of the global ice volume cycles, which matched well with their corresponding oxygen isotope data.As higher NTL intensity occurred within interglacial periods and changes in an NTL signal were most likely influenced by the temperature of ambient seawater in which the planktonic foraminiferal shells long existed, the NTL signal could be considered as a potential proxy for orbital scale temperature changes of bottom seawater in the tropical Indian Ocean.
2008, (2): 35-54.
Abstract:
The major elements, rare earth elements (REE) and trace elements of four basalt samples from central and western Pacific ferromanganese crust provinces have been analyzed using chemical methods and ICP-MS, respectively.The results indicate that the samples have been extensively altered and that the contents of their major elements have changed significantly.However, the similarity of REE partition patterns and trace element contents of basalt samples to those of fresh oceanic island basalts (OIB) indicate that the basalt samples originated as OIB.Because of low-temperature alteration, the contents of Al2O3, Fe2O3, MnO, K2O and P2O5 increased, while MgO and FeO decreased.Active components, such as magnesium and iron, were leached from OIB resulting in the relative enrichment of SiO2.The leaching of active components can cause the relative enrichment of REE, while the precipitation of LREE-rich ferromanganese oxides in vesicles and fissures not only causes an increase of REE contents, but also induces "fractionation" of LREE and HREE.Based on the enrichment mechanism of REE contents, the theoretical quantities of precipitated ferromanganese oxides and the depleted quantities of active components are calculated:the depleted quantities of active components for the unit mass of fresh basalts vary in the range of 0.15~0.657, and the precipitated quantities of ferromanganese oxides for the unit mass of fresh basalts vary in the range of 0.006~0.042.Of the major elements, the two most depleted are iron, and magnesium, with 18.28%~70.95% of iron and 44.50%~93.94% of magnesium in the fresh basalts was leached out.Theoretical calculation and geochemistry results both indicate that low-temperature alteration of basalts can supply abundant amount of metals to seawater, and may play an important role in ocean metal circulation.
The major elements, rare earth elements (REE) and trace elements of four basalt samples from central and western Pacific ferromanganese crust provinces have been analyzed using chemical methods and ICP-MS, respectively.The results indicate that the samples have been extensively altered and that the contents of their major elements have changed significantly.However, the similarity of REE partition patterns and trace element contents of basalt samples to those of fresh oceanic island basalts (OIB) indicate that the basalt samples originated as OIB.Because of low-temperature alteration, the contents of Al2O3, Fe2O3, MnO, K2O and P2O5 increased, while MgO and FeO decreased.Active components, such as magnesium and iron, were leached from OIB resulting in the relative enrichment of SiO2.The leaching of active components can cause the relative enrichment of REE, while the precipitation of LREE-rich ferromanganese oxides in vesicles and fissures not only causes an increase of REE contents, but also induces "fractionation" of LREE and HREE.Based on the enrichment mechanism of REE contents, the theoretical quantities of precipitated ferromanganese oxides and the depleted quantities of active components are calculated:the depleted quantities of active components for the unit mass of fresh basalts vary in the range of 0.15~0.657, and the precipitated quantities of ferromanganese oxides for the unit mass of fresh basalts vary in the range of 0.006~0.042.Of the major elements, the two most depleted are iron, and magnesium, with 18.28%~70.95% of iron and 44.50%~93.94% of magnesium in the fresh basalts was leached out.Theoretical calculation and geochemistry results both indicate that low-temperature alteration of basalts can supply abundant amount of metals to seawater, and may play an important role in ocean metal circulation.
2008, (2): 55-80.
Abstract:
The biogeography of macrobenthic communities with large-scale differences in species distribution and abundance was studied along the eastern and western coastal regions of the Gulf of Suez to indicate biodiversity of benthos in relation to the prevailing environmental conditions.In general, benthos have a wide variety of species of mainly polychaet worms, crustaceans, bivalves, and other bottom invertebrates living in burrows in/or on the sediment surface.Coastal development clearly affects the ecosystem after the construction of coastal projects.The highest values of benthic diversity, evenness, richness and dominance are found at the Gulf of Suez (WG 1, WG 3), Ras Gharib (WG 7, WG 8) and Ras Shukier (WG 9a) by contrast to others.The abundance of macrobenthic organsims along the coasts of Gulf of Suez can be arranged in the following sequence:other groups (34%) greater than crustaceans (25%) greater than polychaetes (22%) greater than molluscs (17%) greater than echinoderms (2%).The biomass of benthic assemblages at different sampling sites can also be ranked as follows:echinoderms (52%) greater than molluscs (27%) greater than crustaceans (16%) greater than polychaetes (2%) greater than other groups (3%).Some benthic groups or species indicated a distinctive correlation to pollution sources in the marine ecosystem which obviously increased in the coastal areas due to the extension of the coastal development.These activities needed regular information to establish database for the biology and distribution of marine benthic communities.The density and diversity of benthos are significantly affected by eutrophication at Ain Sukhna, whereas the benthos in the open Gulf of Suez do not seem to be adversely affected by pollution.
The biogeography of macrobenthic communities with large-scale differences in species distribution and abundance was studied along the eastern and western coastal regions of the Gulf of Suez to indicate biodiversity of benthos in relation to the prevailing environmental conditions.In general, benthos have a wide variety of species of mainly polychaet worms, crustaceans, bivalves, and other bottom invertebrates living in burrows in/or on the sediment surface.Coastal development clearly affects the ecosystem after the construction of coastal projects.The highest values of benthic diversity, evenness, richness and dominance are found at the Gulf of Suez (WG 1, WG 3), Ras Gharib (WG 7, WG 8) and Ras Shukier (WG 9a) by contrast to others.The abundance of macrobenthic organsims along the coasts of Gulf of Suez can be arranged in the following sequence:other groups (34%) greater than crustaceans (25%) greater than polychaetes (22%) greater than molluscs (17%) greater than echinoderms (2%).The biomass of benthic assemblages at different sampling sites can also be ranked as follows:echinoderms (52%) greater than molluscs (27%) greater than crustaceans (16%) greater than polychaetes (2%) greater than other groups (3%).Some benthic groups or species indicated a distinctive correlation to pollution sources in the marine ecosystem which obviously increased in the coastal areas due to the extension of the coastal development.These activities needed regular information to establish database for the biology and distribution of marine benthic communities.The density and diversity of benthos are significantly affected by eutrophication at Ain Sukhna, whereas the benthos in the open Gulf of Suez do not seem to be adversely affected by pollution.
2008, (2): 81-92.
Abstract:
A new member of antimicrobial protein genes of the Crustin family was cloned from haemocytes of the Chinese shrimp Fenneropenaeus chinensis by 3' and 5' RACE.The full-length cDNA of Crustin-like gene contains a 390 bp open reading frame, encoding 130 amino acids.The deduced peptide contains a putative signal peptide of 17 amino acids and mature peptide of 113 amino acids.The molecular mass of the deduced mature peptide is 12.3 ku.It is highly cationic with a theoretical isoelectric point of 8.5.The deduced amino acids sequence of this Crustin showed high homology with those of Penaeus (Litopenaeus) setferus.Northern blotting showed that the cloned Crustin gene was mainly expressed in haemocytes, gill, intestine, and RNA in situ hybridization indicated that the Crustin gene was constitutively expressed exclusively in haemocytes of these tissues.Capillary electrophoresis RT-PCR analysis showed that Crustin was up-regulated dramatically from 12 to 48 h after a brief decrease of mRNA during first 6 h in response to microbe infection.The level of Crustin mRNA began to restore at 72 h post-challenge.This indicated that Crustin gene might play an important role when shrimps are infected by bacterial pathogen.
A new member of antimicrobial protein genes of the Crustin family was cloned from haemocytes of the Chinese shrimp Fenneropenaeus chinensis by 3' and 5' RACE.The full-length cDNA of Crustin-like gene contains a 390 bp open reading frame, encoding 130 amino acids.The deduced peptide contains a putative signal peptide of 17 amino acids and mature peptide of 113 amino acids.The molecular mass of the deduced mature peptide is 12.3 ku.It is highly cationic with a theoretical isoelectric point of 8.5.The deduced amino acids sequence of this Crustin showed high homology with those of Penaeus (Litopenaeus) setferus.Northern blotting showed that the cloned Crustin gene was mainly expressed in haemocytes, gill, intestine, and RNA in situ hybridization indicated that the Crustin gene was constitutively expressed exclusively in haemocytes of these tissues.Capillary electrophoresis RT-PCR analysis showed that Crustin was up-regulated dramatically from 12 to 48 h after a brief decrease of mRNA during first 6 h in response to microbe infection.The level of Crustin mRNA began to restore at 72 h post-challenge.This indicated that Crustin gene might play an important role when shrimps are infected by bacterial pathogen.
2008, (2): 93-101.
Abstract:
A molecular phylogenetic analysis was undertaken to evaluate the present systematic status of commercially familiar Pleuronectidae fishes in the northwestern Pacific Ocean.We sequenced a 529 bp fragment of the mitochondrial DNA (mtDNA) COI gene from 34 individuals of these familiar flatfishes from 11 species of nine genera collected in China and Japan.Genetic relationships among haplotypes of specimens from 11 species for COI gene data were reconstructed using the neighbour-joining method and the maximum parsimony (MP) method.The resulting molecular phylogeny of the 11 species, with a few exceptions, supported the existing taxonomy which was based largely on the morphological characteristics.The most noteworthy findings were that the genus Pleuronichthys diverged before deriving of the common ancestor for the other species; the stone flounder, Kareius biocoloratus, should belong to the genus Platichthys with the latin name Platichthys biocoloratus and the genus Verasper was not the extraordinary differentiation from the other species in family Pleuronectidae.The resultant phylogenetic trees were also consistent with multiple origins of direct development within family Pleuronectidae.New proof not only for further illuminating the multiple origins of Pleuronectidae but also for confirmation of the evolutionary relationships among groups in the family will be supported.
A molecular phylogenetic analysis was undertaken to evaluate the present systematic status of commercially familiar Pleuronectidae fishes in the northwestern Pacific Ocean.We sequenced a 529 bp fragment of the mitochondrial DNA (mtDNA) COI gene from 34 individuals of these familiar flatfishes from 11 species of nine genera collected in China and Japan.Genetic relationships among haplotypes of specimens from 11 species for COI gene data were reconstructed using the neighbour-joining method and the maximum parsimony (MP) method.The resulting molecular phylogeny of the 11 species, with a few exceptions, supported the existing taxonomy which was based largely on the morphological characteristics.The most noteworthy findings were that the genus Pleuronichthys diverged before deriving of the common ancestor for the other species; the stone flounder, Kareius biocoloratus, should belong to the genus Platichthys with the latin name Platichthys biocoloratus and the genus Verasper was not the extraordinary differentiation from the other species in family Pleuronectidae.The resultant phylogenetic trees were also consistent with multiple origins of direct development within family Pleuronectidae.New proof not only for further illuminating the multiple origins of Pleuronectidae but also for confirmation of the evolutionary relationships among groups in the family will be supported.
2008, (2): 102-115.
Abstract:
Nematode assemblage composition, trophic structure and biodiversity were followed over an annual cycle in a sandy beach of the Taiping Bay of Qingdao, China.Nematode assemblage in the sandy beach maintained a high genus diversity (75 genera).Microlaimus and Bathylaimus were the dominant genus of the nematode assemblage, accounting for 66% of the total nematode abundance.The nematodes' dominant trophic structure changed seasonally as a response to the seasonal changes in food quality.Epigrowth-feeder nematodes (2A) were the dominant trophic groups in the trophic structure with the highest abundance in spring because of phytoplankton bloom, while the feeding type (1B) showed higher abundance in summer that was due to the increasing of sediment detritus after spring bloom.Furthermore, species diversity and evenness calculated on nematodes identified to the genus level displayed significant temporal changes, which was also reflected by the index of trophic diversity.According to the cluster analysis, the nematode community structure of the whole year was clearly separated into two periods (A and B).Biota-Environment matching (BIOENV) results showed that seawater temperature, sediment Chl a and grain size were responsible for the nematode community structure variation in spring and summer period (Period A).However, seawater/interstitial water temperature, interstitial water dissolved oxygen concentration, interstitial water salinity, and sediment Ph a a were moreimportant in constructing the autumn and winter period (Period B) nematode community structure.
Nematode assemblage composition, trophic structure and biodiversity were followed over an annual cycle in a sandy beach of the Taiping Bay of Qingdao, China.Nematode assemblage in the sandy beach maintained a high genus diversity (75 genera).Microlaimus and Bathylaimus were the dominant genus of the nematode assemblage, accounting for 66% of the total nematode abundance.The nematodes' dominant trophic structure changed seasonally as a response to the seasonal changes in food quality.Epigrowth-feeder nematodes (2A) were the dominant trophic groups in the trophic structure with the highest abundance in spring because of phytoplankton bloom, while the feeding type (1B) showed higher abundance in summer that was due to the increasing of sediment detritus after spring bloom.Furthermore, species diversity and evenness calculated on nematodes identified to the genus level displayed significant temporal changes, which was also reflected by the index of trophic diversity.According to the cluster analysis, the nematode community structure of the whole year was clearly separated into two periods (A and B).Biota-Environment matching (BIOENV) results showed that seawater temperature, sediment Chl a and grain size were responsible for the nematode community structure variation in spring and summer period (Period A).However, seawater/interstitial water temperature, interstitial water dissolved oxygen concentration, interstitial water salinity, and sediment Ph a a were moreimportant in constructing the autumn and winter period (Period B) nematode community structure.
2008, (2): 116-125.
Abstract:
Over 400 yeast strains from seawater and sediments were obtained, but only five strains named HN2-3, N13d, N13C, Mb5 and HN3-2 among them could form clear zones around their colonies on the double plates with 2.0% casein.Peptides in the hydrolysate produced by the proteases from strains HN2-3 and N13d had higher angiotensin I-converting-enzyme (ACE)-inhibitory activity.The two marine yeast strains were identified to be Aureobasidium pullulans according to the results of routine yeast identification and molecular methods.After purification of the proteases from the two marine yeast strains, it was found that the optimal pH for them was both 9.0, both of them were serine alkaline protease.However, the optimal temperature for the protease from the strain HN2-3 was 52℃ while that from strain N13d was 48℃.ACE-inhibitory activity of the peptides in the hydrolysate of shrimp protein produced by the purified protease from the strain HN2-3 was the highest while antioxidant activity in the hydrolysate of spirulina protein produced by the purified protease from the strain N13d was the highest.
Over 400 yeast strains from seawater and sediments were obtained, but only five strains named HN2-3, N13d, N13C, Mb5 and HN3-2 among them could form clear zones around their colonies on the double plates with 2.0% casein.Peptides in the hydrolysate produced by the proteases from strains HN2-3 and N13d had higher angiotensin I-converting-enzyme (ACE)-inhibitory activity.The two marine yeast strains were identified to be Aureobasidium pullulans according to the results of routine yeast identification and molecular methods.After purification of the proteases from the two marine yeast strains, it was found that the optimal pH for them was both 9.0, both of them were serine alkaline protease.However, the optimal temperature for the protease from the strain HN2-3 was 52℃ while that from strain N13d was 48℃.ACE-inhibitory activity of the peptides in the hydrolysate of shrimp protein produced by the purified protease from the strain HN2-3 was the highest while antioxidant activity in the hydrolysate of spirulina protein produced by the purified protease from the strain N13d was the highest.
2008, (2): 126-132.
Abstract:
The neutralizing activities of eight monoclonal antibodies (MAbs) against white spot syndrome virus (WSSV) (2D2, 2B2, 1D2, 1D5, 1C2, 4A1, 6A4 and 6B4) were analyzed by in vivo experiments.Gills from WSSV-infected shrimp were homogenized and ten-fold serially diluted by PBS, and then incubated with MAbs (hybridoma culture supernatant), respectively.The mixture of WSSV and MAbs were injected into crayfish (Procambarus clarkii).After challenge, the death rates of crayfish were counted to determine the neutralizing activities of MAbs.At the same time, the mixture of myeloma culture supernatant and WSSV or PBS was served as positive or negative control, respectively.The results showed that, at each virus dilution, the mean time to death of the crayfish injected with MAb-treated virus was significantly longer than that in the positive control, though they all showed 100% mortality within 25 d, and meanwhile, few crayfish died in the negative control.Among the eight MAbs, 2D2, 2B2, 1D2 and 1D5, especially the former two, delayed the mortality significantly, and 1C2, 4A1 and 6A4 delayed the mortality as well but not so efficiently, while MAb 6B4 was efficient only when the virus concentration increased.The results indicated that the anti-WSSV MAbs can neutralize WSSV in different virus dilutions.
The neutralizing activities of eight monoclonal antibodies (MAbs) against white spot syndrome virus (WSSV) (2D2, 2B2, 1D2, 1D5, 1C2, 4A1, 6A4 and 6B4) were analyzed by in vivo experiments.Gills from WSSV-infected shrimp were homogenized and ten-fold serially diluted by PBS, and then incubated with MAbs (hybridoma culture supernatant), respectively.The mixture of WSSV and MAbs were injected into crayfish (Procambarus clarkii).After challenge, the death rates of crayfish were counted to determine the neutralizing activities of MAbs.At the same time, the mixture of myeloma culture supernatant and WSSV or PBS was served as positive or negative control, respectively.The results showed that, at each virus dilution, the mean time to death of the crayfish injected with MAb-treated virus was significantly longer than that in the positive control, though they all showed 100% mortality within 25 d, and meanwhile, few crayfish died in the negative control.Among the eight MAbs, 2D2, 2B2, 1D2 and 1D5, especially the former two, delayed the mortality significantly, and 1C2, 4A1 and 6A4 delayed the mortality as well but not so efficiently, while MAb 6B4 was efficient only when the virus concentration increased.The results indicated that the anti-WSSV MAbs can neutralize WSSV in different virus dilutions.
2008, (2): 133-148.
Abstract:
The Zhelin Bay is one of the most important bays for large-scale mariculture in Guangdong Province, China.Owing to the increasing human population and the expanding mariculture in the last two decades, the ecological environment has greatly changed with frequent harmful algal blooms.A monthly survey of water content, organic matter (TOM), and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted.The results showed that the water content was correlated significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys.TOM was also correlated significantly with various forms of nitrogen and phosphorus, indicating that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters.Average total Kjeldhal nitrogen (TkN) content was (1 113.1±382.5)μg/g and average total phosphorus (TP) content was (567.2±223.3)μg/g, and both were much higher than those of similar estuaries in China and elsewhere.Average nitrogen and phosphorus tended to be higher inside than outside the bay, higher at aquaculture than non-aquaculture areas, and higher at fish-cage culture than oyster culture areas, suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay.Various forms of nitrogen and phosphorus concentrations were higher during the warm season (July-September), which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species.Compared with July 2002, TkN and TP contents were much higher in July 2003, in consonance with the eutrophication of the Zhelin Bay.Because exchangeable phosphorus (Ex-P), iron-bounded phosphorus (Fe-P) and organic phosphorus (OP) combined accounted for 34.3% of the TP and authigenic phosphorus (Au-P) accounted for 49.2% of the TP, biological phosphorus (BP) that includes Ex-P, Fe-P, OP, and a portion of Au-P, thus accounted for 34.3% to 83.5% of the TP in the Zhelin Bay, which was within the percentage range, but with a high absolute value among the estuaries.Au-P was the most important species of phosphorus and accounted for 49.2% of the TP during the investigation.Since eutrophication in the water column can lead to reduction of pH in sediment and release of phosphorus in Au-P combined with authigenic spodiosite and calcium carbonate, high content of Au-P in the sediment maybe act as a time bomb that can trigger a vicious cycle of eutrophication and large-scale harmful algal bloom in the Zhelin Bay.
The Zhelin Bay is one of the most important bays for large-scale mariculture in Guangdong Province, China.Owing to the increasing human population and the expanding mariculture in the last two decades, the ecological environment has greatly changed with frequent harmful algal blooms.A monthly survey of water content, organic matter (TOM), and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted.The results showed that the water content was correlated significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys.TOM was also correlated significantly with various forms of nitrogen and phosphorus, indicating that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters.Average total Kjeldhal nitrogen (TkN) content was (1 113.1±382.5)μg/g and average total phosphorus (TP) content was (567.2±223.3)μg/g, and both were much higher than those of similar estuaries in China and elsewhere.Average nitrogen and phosphorus tended to be higher inside than outside the bay, higher at aquaculture than non-aquaculture areas, and higher at fish-cage culture than oyster culture areas, suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay.Various forms of nitrogen and phosphorus concentrations were higher during the warm season (July-September), which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species.Compared with July 2002, TkN and TP contents were much higher in July 2003, in consonance with the eutrophication of the Zhelin Bay.Because exchangeable phosphorus (Ex-P), iron-bounded phosphorus (Fe-P) and organic phosphorus (OP) combined accounted for 34.3% of the TP and authigenic phosphorus (Au-P) accounted for 49.2% of the TP, biological phosphorus (BP) that includes Ex-P, Fe-P, OP, and a portion of Au-P, thus accounted for 34.3% to 83.5% of the TP in the Zhelin Bay, which was within the percentage range, but with a high absolute value among the estuaries.Au-P was the most important species of phosphorus and accounted for 49.2% of the TP during the investigation.Since eutrophication in the water column can lead to reduction of pH in sediment and release of phosphorus in Au-P combined with authigenic spodiosite and calcium carbonate, high content of Au-P in the sediment maybe act as a time bomb that can trigger a vicious cycle of eutrophication and large-scale harmful algal bloom in the Zhelin Bay.
2008, (2): 149-156.
Abstract:
Twenty microsatellite markers (Po1, Po13, Po33, Po35, Po42, Po48, Po56, Po89, Po91, kop6, kop7, kop8, kop12, kop15, kop18, kop21, kop22, kop23, kop26, Po-str1) were used to assess the meiogynogenetic and mitogynogenetic stocks of the left-eyed flounder, Paralichthys olivaceus, which were derived from single pair crossing.Twelve of the 20 loci utilized showed heterozygosity in the female and were mapped in relation to their centromeres in the meiogynogenetic diploid flounder.Microsatellite-centromere map distance, calculated under the assumption of complete interference, ranged from 15.8 cM for kop22 to 50 cM for Po13, Po56 and Po89.Excluding the kop22, the heterozygosities of the rest of the loci were close to 100%, suggesting the occurrence of near complete interference on the chromosome arms that carried these loci.In the mitogynogenetic diploid flounder, each individual showed exact homozygousity and the segregation profiles did not deviate from the Mendelian 1:1 pattern.The results indicated that there was no lethal gene linked with the loci analyzed.Such high interference accounted for the high recombination rates and large map distances.The Po13 and Po56 loci, Po91 and kop18 loci, kop15 and kop21 loci are tightly linked on the same chromosome arm in pairs.
Twenty microsatellite markers (Po1, Po13, Po33, Po35, Po42, Po48, Po56, Po89, Po91, kop6, kop7, kop8, kop12, kop15, kop18, kop21, kop22, kop23, kop26, Po-str1) were used to assess the meiogynogenetic and mitogynogenetic stocks of the left-eyed flounder, Paralichthys olivaceus, which were derived from single pair crossing.Twelve of the 20 loci utilized showed heterozygosity in the female and were mapped in relation to their centromeres in the meiogynogenetic diploid flounder.Microsatellite-centromere map distance, calculated under the assumption of complete interference, ranged from 15.8 cM for kop22 to 50 cM for Po13, Po56 and Po89.Excluding the kop22, the heterozygosities of the rest of the loci were close to 100%, suggesting the occurrence of near complete interference on the chromosome arms that carried these loci.In the mitogynogenetic diploid flounder, each individual showed exact homozygousity and the segregation profiles did not deviate from the Mendelian 1:1 pattern.The results indicated that there was no lethal gene linked with the loci analyzed.Such high interference accounted for the high recombination rates and large map distances.The Po13 and Po56 loci, Po91 and kop18 loci, kop15 and kop21 loci are tightly linked on the same chromosome arm in pairs.
2008, (2): 157-163.
Abstract:
The cortical development and macronuclear evolution of the marine hypotrichous ciliate Anteholosticha manca, collected from the coastal waters near Qingdao, China, were investigated using the protargol impregnation method.The morphogenesis of A.manca is generally typical for the genus, and can be characterized as the following features:(1) in the proter, a new oral primordium is formed on the bottom (beneath the pellicle) of the buccal cavity, disorganization of the parental undulating membranes do not contribute to the formation of this primordium; (2) FVT-cirral anlagen in both dividers develop independently, and very likely only a few midventral cirri join in the formation of these primordia; (3) both marginal row and dorsal kinety anlagen develop intrakinetally within the parental structure; (4) at the middle stage, macronuclear segments fuse together to form a single mass as observed in most of its related forms.
The cortical development and macronuclear evolution of the marine hypotrichous ciliate Anteholosticha manca, collected from the coastal waters near Qingdao, China, were investigated using the protargol impregnation method.The morphogenesis of A.manca is generally typical for the genus, and can be characterized as the following features:(1) in the proter, a new oral primordium is formed on the bottom (beneath the pellicle) of the buccal cavity, disorganization of the parental undulating membranes do not contribute to the formation of this primordium; (2) FVT-cirral anlagen in both dividers develop independently, and very likely only a few midventral cirri join in the formation of these primordia; (3) both marginal row and dorsal kinety anlagen develop intrakinetally within the parental structure; (4) at the middle stage, macronuclear segments fuse together to form a single mass as observed in most of its related forms.
