2006 Vol. 25, No. 2
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Display Method:
2006, (2): 1-24.
Abstract:
Hydrographic data, ADCP velocity and sea level anomaly derived from the satellite altimeter have been jointly analyzed in the southeast Indian Ocean.Results show the locations and orientations of the major oceanic fronts as well as the characteristics of the currents within these fronts in the area.Double subtropical fronts are observed in the section along 120°E, which conflicts with the frontal structure frequently observed before-the North Subtropical Front (NSTF) and South Subtropical Front (SSTF) merge into a single STF between 110°~115°E.The Subantarctic Front (SAF), influenced by the out-of-phase double eddies, runs across 48°S three times between 120° and 127°E.The surface current within the SAF is strengthened up to 105.4 cm/s by the geostrophic effect of these eddies.Furthermore eddies may cause the strong current to split up into two branches within the SAF.The SAF and the primary polar front (PF1) can be identified individually in the ADCP data with a separation distance of about 0.3° at latitude between 140° and 145°E, although they cannot be identified separately in the low-resolution hydrographic data.The different thermohaline characteristics of Circumpolar Deep Water (CDW) and Modified Circumpolar Deep Water (MCDW) result in the formation of Southern Antarctic Circumpolar Current Front (SACCF) in the southeast Indian Ocean.It consistently turns northward along the east flank of the Kerguelen Plateau after it runs through the Princess Elizabeth Trough and turns southward sharply north of 60°S with a little seasonal variations.It is shown that the locations and orientations of the SAF, the primary PF and SACCF in the ACC of the southeast Indian Ocean can be identified more precisely by the current distribution derived from ADCP data than by hydrographic data, because these fronts are usually accompanied by strong currents.However, the locations and orientations of the STF and the secondary PF are more difficult to be identified through current data, since these two fronts are usually not accompanied by any jet.The STF the and the secondary PF are usually confined in the first few hundred meters of the upper ocean and the latter is often determined by the northern terminus of 2℃ isothermal.
Hydrographic data, ADCP velocity and sea level anomaly derived from the satellite altimeter have been jointly analyzed in the southeast Indian Ocean.Results show the locations and orientations of the major oceanic fronts as well as the characteristics of the currents within these fronts in the area.Double subtropical fronts are observed in the section along 120°E, which conflicts with the frontal structure frequently observed before-the North Subtropical Front (NSTF) and South Subtropical Front (SSTF) merge into a single STF between 110°~115°E.The Subantarctic Front (SAF), influenced by the out-of-phase double eddies, runs across 48°S three times between 120° and 127°E.The surface current within the SAF is strengthened up to 105.4 cm/s by the geostrophic effect of these eddies.Furthermore eddies may cause the strong current to split up into two branches within the SAF.The SAF and the primary polar front (PF1) can be identified individually in the ADCP data with a separation distance of about 0.3° at latitude between 140° and 145°E, although they cannot be identified separately in the low-resolution hydrographic data.The different thermohaline characteristics of Circumpolar Deep Water (CDW) and Modified Circumpolar Deep Water (MCDW) result in the formation of Southern Antarctic Circumpolar Current Front (SACCF) in the southeast Indian Ocean.It consistently turns northward along the east flank of the Kerguelen Plateau after it runs through the Princess Elizabeth Trough and turns southward sharply north of 60°S with a little seasonal variations.It is shown that the locations and orientations of the SAF, the primary PF and SACCF in the ACC of the southeast Indian Ocean can be identified more precisely by the current distribution derived from ADCP data than by hydrographic data, because these fronts are usually accompanied by strong currents.However, the locations and orientations of the STF and the secondary PF are more difficult to be identified through current data, since these two fronts are usually not accompanied by any jet.The STF the and the secondary PF are usually confined in the first few hundred meters of the upper ocean and the latter is often determined by the northern terminus of 2℃ isothermal.
2006, (2): 25-32.
Abstract:
The temperature and salinity data obtained by the Chinese national arctic research expedition (CHINARE2003) are used to study the water structure in the Bering Strait and ambient regions.Four water masses appeared in the research region:the intermediate Bering Sea water mass (IBWM), the Alaska coastal water (ACW), the Anadyr water (AW) and the Bering shelf water (BSW).The AW originates from the IBWM, but the upper layer water has been greatly altered.In the cruise on 28/29 July 2003, there were only the BSW and ACW in a section across the Bering Strait (BS section), but in the September 12/13 cruise, the AW, BSW and ACW flowed parallelly into the Bering Strait.The upper waters of these water masses were all altered due to ice melting, runoff, solar radiation, and wind mixing.The waters in the central and northern parts of Bering Strait stratified by two uniform layers, were expressed as the typical feature of the water masses originating from the pacific.A two-layer structure also dominated the vertical stratification in most part of the Chukchi Sea.An obvious subseasonal variation was observed in the BS section, which caused varying transportation of fresh water, heat, and substance, and produced a long-term and extensive impact on the Arctic Ocean.
The temperature and salinity data obtained by the Chinese national arctic research expedition (CHINARE2003) are used to study the water structure in the Bering Strait and ambient regions.Four water masses appeared in the research region:the intermediate Bering Sea water mass (IBWM), the Alaska coastal water (ACW), the Anadyr water (AW) and the Bering shelf water (BSW).The AW originates from the IBWM, but the upper layer water has been greatly altered.In the cruise on 28/29 July 2003, there were only the BSW and ACW in a section across the Bering Strait (BS section), but in the September 12/13 cruise, the AW, BSW and ACW flowed parallelly into the Bering Strait.The upper waters of these water masses were all altered due to ice melting, runoff, solar radiation, and wind mixing.The waters in the central and northern parts of Bering Strait stratified by two uniform layers, were expressed as the typical feature of the water masses originating from the pacific.A two-layer structure also dominated the vertical stratification in most part of the Chukchi Sea.An obvious subseasonal variation was observed in the BS section, which caused varying transportation of fresh water, heat, and substance, and produced a long-term and extensive impact on the Arctic Ocean.
2006, (2): 33-48.
Abstract:
POM (Princeton ocean model) tentatively taken as the ocean part of an ocean-land-atmosphere coupled model is verified for the ultimate purpose of studying the landfall process of tropical cyclone (TC) in the western North Pacific.The POM is tested with monthly mean wind stress in the summer and given lateral boundary conditions.The results indicate that the equilibrium state of the ocean is in accordance with the climate mean, with the error in sea surface temperature (salinity) less than 0.5℃ (0.5).The simulated ocean currents are reasonable as well.Several numerical experiments are designed to verify the oceanic response to a stationary or moving TC.It is found that the results agree fairly well with the previous work, including both the drop magnitude and the distribution of sea temperature.Compared with the simple two-layer ocean model used by some other studies, the response of the ocean to a TC is more logical here.The model is also verified in a real case with a TC passing the neighborhood of a buoy station.It is shown that the established ocean model can basically reproduce the sea surface temperature change as observed.
POM (Princeton ocean model) tentatively taken as the ocean part of an ocean-land-atmosphere coupled model is verified for the ultimate purpose of studying the landfall process of tropical cyclone (TC) in the western North Pacific.The POM is tested with monthly mean wind stress in the summer and given lateral boundary conditions.The results indicate that the equilibrium state of the ocean is in accordance with the climate mean, with the error in sea surface temperature (salinity) less than 0.5℃ (0.5).The simulated ocean currents are reasonable as well.Several numerical experiments are designed to verify the oceanic response to a stationary or moving TC.It is found that the results agree fairly well with the previous work, including both the drop magnitude and the distribution of sea temperature.Compared with the simple two-layer ocean model used by some other studies, the response of the ocean to a TC is more logical here.The model is also verified in a real case with a TC passing the neighborhood of a buoy station.It is shown that the established ocean model can basically reproduce the sea surface temperature change as observed.
2006, (2): 49-62.
Abstract:
With the sea surface observations from ICOADS for the years 1960~2002, the conditions of cooling, evaporation and water vapor transportation are analyzed and compared for the formation of seasonal sea fog in April-July in the Huanghai Sea.It is found that sea surface cooling is always existent during the fog seasons while sea surface evaporation only appears in April-June in the Huanghai Sea.Local evaporation alone is not sufficient to form fogs though it may lead to light ones.Water vapor transported from the low-latitudes accomplished by specific synoptic systems is the most important condition for sea fog formation.In general, the moistening effect is more important than the cooling one.
With the sea surface observations from ICOADS for the years 1960~2002, the conditions of cooling, evaporation and water vapor transportation are analyzed and compared for the formation of seasonal sea fog in April-July in the Huanghai Sea.It is found that sea surface cooling is always existent during the fog seasons while sea surface evaporation only appears in April-June in the Huanghai Sea.Local evaporation alone is not sufficient to form fogs though it may lead to light ones.Water vapor transported from the low-latitudes accomplished by specific synoptic systems is the most important condition for sea fog formation.In general, the moistening effect is more important than the cooling one.
2006, (2): 63-70.
Abstract:
Using the SeaBeam technology, the morphology of seamount and its relation to the formation of cobalt-rich crust in the central Pacific Ocean were surveyed during the cruise in 2003 for marine mineral resources.The result shows that seamounts can be divided morphologically into the spire seamount and the flat topped seamount.These two types of seamount bear great differences in their landform, lithology and cobalt-rich crust.On the upper portion of the flat topped seamount, the flat top and the sharp escarpments are unfavorable to the growth of crust, and, consequently, the crusts here are mostly laminar or gravelly, their thicknesses generally show great variations, and the consecutive ore body often develops in its deep water region.On the spire topped seamount, however, the flat area is small, and its gradient is constant without large variation from the top to the bottom.This favors the growth of cobalt-rich crust and often leads to consecutive tabular ore body of medium thickness, occurring on the spire topped seamount from the shallow water region to the deep water region.The cobalt-rich crust on the spire topped seamount is much better than that on the flat topped seamount for the crust abundance, crust coverage and number of ore-occurrences within unit area.Furthermore, the crust on the spire topped seamount is rich in cobalt, nickel, manganese elements of high economic value.Because the crust with high quality ore often occurs in the shallow water region on the spire topped seamount, it can be mined and use more easily in the future.
Using the SeaBeam technology, the morphology of seamount and its relation to the formation of cobalt-rich crust in the central Pacific Ocean were surveyed during the cruise in 2003 for marine mineral resources.The result shows that seamounts can be divided morphologically into the spire seamount and the flat topped seamount.These two types of seamount bear great differences in their landform, lithology and cobalt-rich crust.On the upper portion of the flat topped seamount, the flat top and the sharp escarpments are unfavorable to the growth of crust, and, consequently, the crusts here are mostly laminar or gravelly, their thicknesses generally show great variations, and the consecutive ore body often develops in its deep water region.On the spire topped seamount, however, the flat area is small, and its gradient is constant without large variation from the top to the bottom.This favors the growth of cobalt-rich crust and often leads to consecutive tabular ore body of medium thickness, occurring on the spire topped seamount from the shallow water region to the deep water region.The cobalt-rich crust on the spire topped seamount is much better than that on the flat topped seamount for the crust abundance, crust coverage and number of ore-occurrences within unit area.Furthermore, the crust on the spire topped seamount is rich in cobalt, nickel, manganese elements of high economic value.Because the crust with high quality ore often occurs in the shallow water region on the spire topped seamount, it can be mined and use more easily in the future.
2006, (2): 71-79.
Abstract:
The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively.A monthly dataset of water discharge, suspended sediment concentration (SSC) and sediment load of the Changjiang River from 1953 to 2003 measured at the Datong Hydrological Gauging Station of the downstreammost Changjiang River was mainly used to examine the Changjiang River sediment delivering into the sea in 2003 in response to the Sanxia Reservoir water storages in the same year.The results show that (1) compared with those in 2002, 2001, and the multi-yearly (1953~2000) average, both annual SSC and sediment load at Datong in 2003 were markedly reduced, and they were even smaller than the multi-yearly (1953~2000) minimum, although the annual runoff in 2003 did not change largely; and (2) compared with those in the corresponding months in 2002, 2001 and the multi-monthly average from 1953 to 2000, monthly SSC and sediment load at Datong both in June and November of 2003 were also markedly reduced, and those in June 2003 were even smaller than the multi-monthly minimum from 1953 to 2000.These may indicate that sediment sedimentation in the Sanxia Reservoir resulting from the Sanxia Reservoir water storage should be the main cause of the decreased annual and monthly SSC and sediment load of the Changjiang River into the sea in 2003.Besides, it seems that the Sanxia Reservoir water storage in the early June (flood season) of 2003 had more impacts on the decreased monthly SSC into the sea than that in the late October and early November (approximately non-flood season) of 2003.
The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively.A monthly dataset of water discharge, suspended sediment concentration (SSC) and sediment load of the Changjiang River from 1953 to 2003 measured at the Datong Hydrological Gauging Station of the downstreammost Changjiang River was mainly used to examine the Changjiang River sediment delivering into the sea in 2003 in response to the Sanxia Reservoir water storages in the same year.The results show that (1) compared with those in 2002, 2001, and the multi-yearly (1953~2000) average, both annual SSC and sediment load at Datong in 2003 were markedly reduced, and they were even smaller than the multi-yearly (1953~2000) minimum, although the annual runoff in 2003 did not change largely; and (2) compared with those in the corresponding months in 2002, 2001 and the multi-monthly average from 1953 to 2000, monthly SSC and sediment load at Datong both in June and November of 2003 were also markedly reduced, and those in June 2003 were even smaller than the multi-monthly minimum from 1953 to 2000.These may indicate that sediment sedimentation in the Sanxia Reservoir resulting from the Sanxia Reservoir water storage should be the main cause of the decreased annual and monthly SSC and sediment load of the Changjiang River into the sea in 2003.Besides, it seems that the Sanxia Reservoir water storage in the early June (flood season) of 2003 had more impacts on the decreased monthly SSC into the sea than that in the late October and early November (approximately non-flood season) of 2003.
2006, (2): 80-86.
Abstract:
Marine geographic information system (MGIS) has great ability to deal with the spatio-temporal problems and has potential superiority when it is applied to oceanography.Using the feature extraction of oceanic phenomena as a case study, the functions of the MGIS are analyzed, and thus the position of MGIS in the oceanography is defined.Comparing the requirement of MGIS with that of the traditional GIS which has been developed in the terrestrial applications in the past four decades, the frame for the functions of MGIS is constructed.According to the established MGIS, some key technologies are discussed in detail with emphasis on the specialities which can distinguish the MGIS from the traditional GIS.
Marine geographic information system (MGIS) has great ability to deal with the spatio-temporal problems and has potential superiority when it is applied to oceanography.Using the feature extraction of oceanic phenomena as a case study, the functions of the MGIS are analyzed, and thus the position of MGIS in the oceanography is defined.Comparing the requirement of MGIS with that of the traditional GIS which has been developed in the terrestrial applications in the past four decades, the frame for the functions of MGIS is constructed.According to the established MGIS, some key technologies are discussed in detail with emphasis on the specialities which can distinguish the MGIS from the traditional GIS.
2006, (2): 87-98.
Abstract:
Free-living marine nematodes were sampled and studied at a grid of 22 stations (from 32°29.35' to 37°0.56'N, 122°0.37' to 125°1.16'E) in the southern Huanghai Sea in January 2003.Nematode abundance varied from 50.5 to 127.2 ind./cm2[(83.1±24.7) ind./cm2] at different stations, 80.1% of the total nematodes were in the surface layer (0~2cm) of sediments.Two hundred and twenty-three species or taxa of marine nematodes belonging to 145 genera, 32 families and four orders were identified and first recorded in the Huanghai Sea.The common dominant species were Dorylaimopsis rabalaisi, Terschellingia longicaudata, Sphaerolaimus balticus, Metalinhomoeus longiseta, Quadricoma scanica, Prochromadorella sp., Paramonohystera riemanni, Marylynnia sp.1, Vasostoma spiratum, Halalaimus spp., Pierrickia sp.1 and Promonhysterafaber.Nematode diversity was correlated with sediment granularity.Pearson correlation analysis showed that Shannon-Wiener index had highly significant positive correlation with a sand content and negative correlation with a silt-clay content (P<0.01); species richness index (d) had significant positive correlation with the sand content and negative correlation with the silt-clay content (P<0.05).The diversity of the southern Huanghai Sea was lower than that in the center of Bohai Sea, but the dominance was higher.
Free-living marine nematodes were sampled and studied at a grid of 22 stations (from 32°29.35' to 37°0.56'N, 122°0.37' to 125°1.16'E) in the southern Huanghai Sea in January 2003.Nematode abundance varied from 50.5 to 127.2 ind./cm2[(83.1±24.7) ind./cm2] at different stations, 80.1% of the total nematodes were in the surface layer (0~2cm) of sediments.Two hundred and twenty-three species or taxa of marine nematodes belonging to 145 genera, 32 families and four orders were identified and first recorded in the Huanghai Sea.The common dominant species were Dorylaimopsis rabalaisi, Terschellingia longicaudata, Sphaerolaimus balticus, Metalinhomoeus longiseta, Quadricoma scanica, Prochromadorella sp., Paramonohystera riemanni, Marylynnia sp.1, Vasostoma spiratum, Halalaimus spp., Pierrickia sp.1 and Promonhysterafaber.Nematode diversity was correlated with sediment granularity.Pearson correlation analysis showed that Shannon-Wiener index had highly significant positive correlation with a sand content and negative correlation with a silt-clay content (P<0.01); species richness index (d) had significant positive correlation with the sand content and negative correlation with the silt-clay content (P<0.05).The diversity of the southern Huanghai Sea was lower than that in the center of Bohai Sea, but the dominance was higher.
2006, (2): 99-108.
Abstract:
Nucleotide sequences from 18S rDNA of 11 ostracodes, which represent four suborders and six superfamilies of podocopidan, were determined.The phylogenetic relationships were analyzed based on three kinds of methods (maximum-likelihood, maximum-parsimony, and neighbor-joining), and the three topologies gained were basically similar.The results have showed that (1) a monophyletic Podocopida was supported strongly; (2) the phylogenetic relationships of four suborders were (Darwinulocopina plus (Bairdiocopina plus (Cytherocopina plus Cypridocopina))), which indicated that a close relationship between Cytherocopina and Cypridocopina, and Darwinulocopina had separated early from the main podocopinan; (3) Cypridocopinan formed a monophyletic group, among which the phylogenetic relationship of three superfamilies was (Cypridoidea plus (Macrocypridoidea plus Pontocypridoidea)).
Nucleotide sequences from 18S rDNA of 11 ostracodes, which represent four suborders and six superfamilies of podocopidan, were determined.The phylogenetic relationships were analyzed based on three kinds of methods (maximum-likelihood, maximum-parsimony, and neighbor-joining), and the three topologies gained were basically similar.The results have showed that (1) a monophyletic Podocopida was supported strongly; (2) the phylogenetic relationships of four suborders were (Darwinulocopina plus (Bairdiocopina plus (Cytherocopina plus Cypridocopina))), which indicated that a close relationship between Cytherocopina and Cypridocopina, and Darwinulocopina had separated early from the main podocopinan; (3) Cypridocopinan formed a monophyletic group, among which the phylogenetic relationship of three superfamilies was (Cypridoidea plus (Macrocypridoidea plus Pontocypridoidea)).
2006, (2): 109-118.
Abstract:
An investigation was carried out in the Huanghai Sea and the East China Sea to study the quantitative relationship between the abundance of flagellates and the density of suspended particles in the summer of 2001.The results show that the abundance of flagellates varies from 44~12 600 cell/cm3, and flagellates sometimes constitutes a significant part of suspended particles.The size-spectra of suspended particles can be divided into four categories:flat spectrum, humped spectrum, plankton spectrum and mixed spectrum.In general, the abundance of flagellates varies in proportion to the density of suspended particles.However, their quantitative relations reveal different characteristics in the seawater samples of different types of particle-size spectrum.This is only a preliminary study of the quantitative relationship between flagellates and suspended particles, which might lead to a potential convenient approach to the estimation of flagellate abundance in the sea.
An investigation was carried out in the Huanghai Sea and the East China Sea to study the quantitative relationship between the abundance of flagellates and the density of suspended particles in the summer of 2001.The results show that the abundance of flagellates varies from 44~12 600 cell/cm3, and flagellates sometimes constitutes a significant part of suspended particles.The size-spectra of suspended particles can be divided into four categories:flat spectrum, humped spectrum, plankton spectrum and mixed spectrum.In general, the abundance of flagellates varies in proportion to the density of suspended particles.However, their quantitative relations reveal different characteristics in the seawater samples of different types of particle-size spectrum.This is only a preliminary study of the quantitative relationship between flagellates and suspended particles, which might lead to a potential convenient approach to the estimation of flagellate abundance in the sea.
2006, (2): 119-124.
Abstract:
The regulation of three biogenic amines over the reproductive neuroendocrine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation.The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes.The in vivo injections indicated that:5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S.serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group.In vitro incubations showed that:5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass.As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion.It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments.Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.
The regulation of three biogenic amines over the reproductive neuroendocrine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation.The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes.The in vivo injections indicated that:5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S.serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group.In vitro incubations showed that:5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass.As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion.It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments.Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.
2006, (2): 125-134.
Abstract:
Ribulose-1, 5-bisphosphate carboxynase/oxygenase large subunit gene (rbcL) of Jiaozhou Bay phytoplankton was amplified from spring, summer and autumn surface seawater DNAs and cloned respectively.About 50 clones were randomly selected from each library and sequenced.If identical amino acid sequences are considered as the same operational taxonomy unit (OTU), 61 OTUs are identified according to inferred amino acid sequences, among them, 21 from spring seawater, 15 from summer seawater and 25 from autumn seawater.Shannon index calculated from OTU abundances reflects the genetic diversity of a community.The indexes of spring, summer and autumn surface seawater phytoplankton are 2.69, 2.44 and 2.76 respectively, indicating that phytoplankton genetic diversity of autumn seawater is the richest.Seasonal variation of phytoplankton community is significant; the community compositions of three seasons are almost completely different except for the two OTUs shared by summer and autumn.Surface seawater phytoplankton communities are possibly metacommunities different spatially and temporally.
Ribulose-1, 5-bisphosphate carboxynase/oxygenase large subunit gene (rbcL) of Jiaozhou Bay phytoplankton was amplified from spring, summer and autumn surface seawater DNAs and cloned respectively.About 50 clones were randomly selected from each library and sequenced.If identical amino acid sequences are considered as the same operational taxonomy unit (OTU), 61 OTUs are identified according to inferred amino acid sequences, among them, 21 from spring seawater, 15 from summer seawater and 25 from autumn seawater.Shannon index calculated from OTU abundances reflects the genetic diversity of a community.The indexes of spring, summer and autumn surface seawater phytoplankton are 2.69, 2.44 and 2.76 respectively, indicating that phytoplankton genetic diversity of autumn seawater is the richest.Seasonal variation of phytoplankton community is significant; the community compositions of three seasons are almost completely different except for the two OTUs shared by summer and autumn.Surface seawater phytoplankton communities are possibly metacommunities different spatially and temporally.
2006, (2): 135-141.
Abstract:
Antarctic ice microalga Chlamydomonas sp.can thrive undisturbed under high UV radiation in the Antarctic ice layer.However, it is unknown that the initial adaptation mechanisms in protein level occurring in response to high UV radiation.Global-expression profiling of proteins in response to stress was analyzed by two-dimensional electrophoresis (2-DE) and image analysis.In the 2-DE analysis, protein preparation is the key step.Three different protein extract methods were compared, and the results showed that the trichloroacetic acid (TCA)-acetone fractional precipitation method was the fittest one.At the same time, the proteins in Chlamydomonas sp.were compared in 2-DE way, and the synthesis of seven protein spots was found disappeared and 18 decreased after exposed to UV-B radiation.In addition, 14 protein spots were enhanced or induced, among which two new peptides (20 and 21 kDa) appeared whose isoelectric point (pI) was 7.05 and 4.60 respectively.These changed proteins might act as key role in the acclimation of Antarctic ice microalga to UV-B radiation.
Antarctic ice microalga Chlamydomonas sp.can thrive undisturbed under high UV radiation in the Antarctic ice layer.However, it is unknown that the initial adaptation mechanisms in protein level occurring in response to high UV radiation.Global-expression profiling of proteins in response to stress was analyzed by two-dimensional electrophoresis (2-DE) and image analysis.In the 2-DE analysis, protein preparation is the key step.Three different protein extract methods were compared, and the results showed that the trichloroacetic acid (TCA)-acetone fractional precipitation method was the fittest one.At the same time, the proteins in Chlamydomonas sp.were compared in 2-DE way, and the synthesis of seven protein spots was found disappeared and 18 decreased after exposed to UV-B radiation.In addition, 14 protein spots were enhanced or induced, among which two new peptides (20 and 21 kDa) appeared whose isoelectric point (pI) was 7.05 and 4.60 respectively.These changed proteins might act as key role in the acclimation of Antarctic ice microalga to UV-B radiation.
2006, (2): 142-152.
Abstract:
The mechanism of local scour around submarine pipelines is studied numerically based on a renormalized group (RNG) turbulence model.To validate the numerical model, the equilibrium profiles of local scour for two cases are simulated and compared with the experimental data.It shows that the RNG turbulence model can give an appropriate prediction for the configuration of equilibrium scour hole, and it is applicable to this situation.The local scour mechanism around submarine pipelines including the flow structure, shear stress distribution and pressure field is then analyzed and compared with experiments.For further comparison and validation, especially for the flow structure, a numerical calculation employing the large eddy simulation (LES) is also conducted.The numerical results of RNG demonstrate that the critical factor governing the equilibrium profile is the seabed shear stress distribution in the case of bed load sediment transport, and the two-equation RNG turbulence model coupled with the law of wall is capable of giving a satisfying estimation for the bed shear stress.Moreover, the piping phenomena due to the great difference of pressure between the upstream and downstream parts of pipelines and the vortex structure around submarine pipelines are also simulated successfully, which are believed to be the important factor that lead to the onset of local scour.
The mechanism of local scour around submarine pipelines is studied numerically based on a renormalized group (RNG) turbulence model.To validate the numerical model, the equilibrium profiles of local scour for two cases are simulated and compared with the experimental data.It shows that the RNG turbulence model can give an appropriate prediction for the configuration of equilibrium scour hole, and it is applicable to this situation.The local scour mechanism around submarine pipelines including the flow structure, shear stress distribution and pressure field is then analyzed and compared with experiments.For further comparison and validation, especially for the flow structure, a numerical calculation employing the large eddy simulation (LES) is also conducted.The numerical results of RNG demonstrate that the critical factor governing the equilibrium profile is the seabed shear stress distribution in the case of bed load sediment transport, and the two-equation RNG turbulence model coupled with the law of wall is capable of giving a satisfying estimation for the bed shear stress.Moreover, the piping phenomena due to the great difference of pressure between the upstream and downstream parts of pipelines and the vortex structure around submarine pipelines are also simulated successfully, which are believed to be the important factor that lead to the onset of local scour.
2006, (2): 153-158.
Abstract:
The process of adsorption of Cu2+, Cd2+ by immobilized marine algae was investigated.It can be noted from the results that, the process for biosorption of heavy metals (copper, cadmium) by immobilized Laminaria japonica can be described by the Banerm model.According to the model, the adsorption rate constant calculated was 0.107 8 and 0.030 28 min-1 for Cu2+ and Cd2+ respectively.The experimental biosorption equilibrium data for Cu2+ and Cd2+ were in good agreement with those calculated by the Langmuir model.The maximum uptake capacity calculated was 83.3 and 112.4 mg/g for Cu2+ and Cd2+ according to the Langmuir model, respectively.The appetency of Laminaria japonica to Cu2+was better than Cd2+.
The process of adsorption of Cu2+, Cd2+ by immobilized marine algae was investigated.It can be noted from the results that, the process for biosorption of heavy metals (copper, cadmium) by immobilized Laminaria japonica can be described by the Banerm model.According to the model, the adsorption rate constant calculated was 0.107 8 and 0.030 28 min-1 for Cu2+ and Cd2+ respectively.The experimental biosorption equilibrium data for Cu2+ and Cd2+ were in good agreement with those calculated by the Langmuir model.The maximum uptake capacity calculated was 83.3 and 112.4 mg/g for Cu2+ and Cd2+ according to the Langmuir model, respectively.The appetency of Laminaria japonica to Cu2+was better than Cd2+.
