2012 Vol. 31, No. 1
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Display Method:
2012, (1): 1-15.
doi: 10.1007/s13131-012-0170-7
Abstract:
Mesoscale eddy activity and its modulation mechanism in the South China Sea (SCS) are investigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy (EKE) level of basin-wide averages show a distinct seasonal cycle with the maximum in August-December and the minimum in February-May. Furthermore, the seasonal pattern of EKE in the basin is dominated by region offshore of central Vietnam (OCV), southwest of Taiwan Island (SWT), and southwest of Luzon (SWL), which are also the breeding grounds of mesoscale eddies in the SCS. Instability theory analysis suggests that the seasonal cycle of EKE is modulated by the baroclinic instability of the mean flow. High eddy growth rate (EGR) is found in the active eddy regions. Vertical velocity shear in the upper 50-500 m is crucial for the growth of baroclinic instability, leading to seasonal EKE evolution in the SCS.
Mesoscale eddy activity and its modulation mechanism in the South China Sea (SCS) are investigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy (EKE) level of basin-wide averages show a distinct seasonal cycle with the maximum in August-December and the minimum in February-May. Furthermore, the seasonal pattern of EKE in the basin is dominated by region offshore of central Vietnam (OCV), southwest of Taiwan Island (SWT), and southwest of Luzon (SWL), which are also the breeding grounds of mesoscale eddies in the SCS. Instability theory analysis suggests that the seasonal cycle of EKE is modulated by the baroclinic instability of the mean flow. High eddy growth rate (EGR) is found in the active eddy regions. Vertical velocity shear in the upper 50-500 m is crucial for the growth of baroclinic instability, leading to seasonal EKE evolution in the SCS.
2012, (1): 16-23.
doi: 10.1007/s13131-012-0171-6
Abstract:
The influence of horizontal mixing on the thermal structure of the equatorial Pacific Ocean is examined based on a sigma coordinate model.In general,the distributions of the temperature and currents simulated by the sigma coordinate model are very close to the climatology.However, the simulated thermocline along the equator is slightly diffusive so that there is a cold bias above the main thermocline,while there is a warm bias under the main thermocline.Both horizontal diffusivity and viscosity have important effects on the upper thermal structure in the equatorial Pacific Ocean,while their detailed dynamics are different.Horizontal diffusivity affects the thermal structure in the upper ocean mainly through regulating the vertical diffusivity,while the horizontal viscosity does mainly through regulating directly the circulate system.A large horizontal diffusivity or a small horizontal viscosity can be in favor of simulating a more realistically thermal structure in the equatorial Pacific Ocean.
The influence of horizontal mixing on the thermal structure of the equatorial Pacific Ocean is examined based on a sigma coordinate model.In general,the distributions of the temperature and currents simulated by the sigma coordinate model are very close to the climatology.However, the simulated thermocline along the equator is slightly diffusive so that there is a cold bias above the main thermocline,while there is a warm bias under the main thermocline.Both horizontal diffusivity and viscosity have important effects on the upper thermal structure in the equatorial Pacific Ocean,while their detailed dynamics are different.Horizontal diffusivity affects the thermal structure in the upper ocean mainly through regulating the vertical diffusivity,while the horizontal viscosity does mainly through regulating directly the circulate system.A large horizontal diffusivity or a small horizontal viscosity can be in favor of simulating a more realistically thermal structure in the equatorial Pacific Ocean.
2012, (1): 24-32.
doi: 10.1007/s13131-012-0172-5
Abstract:
Wave dissipation characteristics in SWAN (Simulating Waves Nearshore) model are investigated through numerical experiments. It is found that neither the fully developed integral parameters of wind waves (significant wave height and peak frequency) nor the high frequency spectral tail can be well reproduced by the default wave dissipation source terms. A new spectral dissipation source term is proposed, which comprises saturation based dissipation above two times of peak frequency and improved whitecapping dissipation at lower frequency spectrum. The reciprocal wave age (u*/cp) is involved into the whitecapping model to adjust dissipation rate at different wind speed. The Phillips higher frequency saturation parameter in the saturation-based dissipation is no longer taken as a constant, but varies with wave age. Numerical validations demonstrate that both the wind wave generation process and higher frequency spectrum of wind waves can be well simulated by the new wave dissipation term.
Wave dissipation characteristics in SWAN (Simulating Waves Nearshore) model are investigated through numerical experiments. It is found that neither the fully developed integral parameters of wind waves (significant wave height and peak frequency) nor the high frequency spectral tail can be well reproduced by the default wave dissipation source terms. A new spectral dissipation source term is proposed, which comprises saturation based dissipation above two times of peak frequency and improved whitecapping dissipation at lower frequency spectrum. The reciprocal wave age (u*/cp) is involved into the whitecapping model to adjust dissipation rate at different wind speed. The Phillips higher frequency saturation parameter in the saturation-based dissipation is no longer taken as a constant, but varies with wave age. Numerical validations demonstrate that both the wind wave generation process and higher frequency spectrum of wind waves can be well simulated by the new wave dissipation term.
2012, (1): 33-40.
doi: 10.1007/s13131-012-0173-4
Abstract:
The research on sea ice resources is the academic base of sea ice exploitation in the Bohai Sea. According to the ice-water spectrum differences and the correlation between ice thickness and albedo, this paper comes up with a sea ice thickness inversion model based on the NOAA/AVHRR data. And then a sea ice resources quantity (SIQ) time series of Bohai Sea is established from 1987 to 2009. The results indicate that the average error of inversion sea ice thickness is below 30%. The maximum sea ice resources quantity is about 6×109 m3 and the minimum is 1.3×109 m3. And a preliminary analysis has been made on the errors of the estimate of sea ice resources quantity (SIQ).
The research on sea ice resources is the academic base of sea ice exploitation in the Bohai Sea. According to the ice-water spectrum differences and the correlation between ice thickness and albedo, this paper comes up with a sea ice thickness inversion model based on the NOAA/AVHRR data. And then a sea ice resources quantity (SIQ) time series of Bohai Sea is established from 1987 to 2009. The results indicate that the average error of inversion sea ice thickness is below 30%. The maximum sea ice resources quantity is about 6×109 m3 and the minimum is 1.3×109 m3. And a preliminary analysis has been made on the errors of the estimate of sea ice resources quantity (SIQ).
2012, (1): 41-50.
doi: 10.1007/s13131-012-0174-3
Abstract:
This paper proposes a rain considered geophysical model function (GMF), to be noted as GMF plus Rain. GMF plus Rain is based on the basic raidative transfer model with attenuation and scattering effects of rain on radar signal considered. Combined with the NSCAT2 GMF and the rain correction model, the GMF plus Rain model is used to retrieve the ocean wind vectors from the collocated QuikSCAT and SSM/I rain rate data for typhoon Melor. The resulting wind speed estimates of typhoon Melor show improved agreement with the wind fields derived from the best track analysis of Japan Meteorological Agency (JMA). The results imply that compared with the GMF model, the GMF plus Rain model can improve the precision of wind retrieval under the rain condition. Then, a new general algorithm of locating the eye of typhoon through the normalized radar cross section (NRCS) is proposed. The implementation of this algorithm in the ten QuikSCAT observations of typhoon Melor suggests that this algorithm is effective.
This paper proposes a rain considered geophysical model function (GMF), to be noted as GMF plus Rain. GMF plus Rain is based on the basic raidative transfer model with attenuation and scattering effects of rain on radar signal considered. Combined with the NSCAT2 GMF and the rain correction model, the GMF plus Rain model is used to retrieve the ocean wind vectors from the collocated QuikSCAT and SSM/I rain rate data for typhoon Melor. The resulting wind speed estimates of typhoon Melor show improved agreement with the wind fields derived from the best track analysis of Japan Meteorological Agency (JMA). The results imply that compared with the GMF model, the GMF plus Rain model can improve the precision of wind retrieval under the rain condition. Then, a new general algorithm of locating the eye of typhoon through the normalized radar cross section (NRCS) is proposed. The implementation of this algorithm in the ten QuikSCAT observations of typhoon Melor suggests that this algorithm is effective.
2012, (1): 51-58.
doi: 10.1007/s13131-012-0175-2
Abstract:
Category 5 typhoon Megi was the most intense typhoon in 2010 of the world. It lingered in the South China Sea (SCS) for 5 d and caused a significant phytoplankton bloom detected by the satellite image. In this study, the authors investigated the ocean biological and physical responses to typhoon Megi by using chlorophyll-a (chl-a) concentration, sea surface temperature (SST), sea surface height anomaly (SSHA), sea surface wind measurements derived from different satellites and in situ data. The chl-a concentration (>3 mg/m3) increased thirty times in the SCS after the typhoon passage in comparison with the mean level of October averaged from 2002 to 2009. With the relationship of wind stress curl and upwelling, the authors found that the speed of upwelling was over ten times during typhoon than pre-typhoon period. Moreover, the mixed layer deepened about 20 m. These reveal that the enhancement of chl-a concentration was triggered by strong vertical mixing and upwelling. Along the track of typhoon, the maximum sea surface cooling (6-8℃) took place in the SCS where the moving speed of typhoon was only 1.4-2.8 m/s and the mixed layer depth was about 20 m in pre-typhoon period. However, the SST drop at the east of the Philippines is only 1-2℃ where the translation speed of typhoon was 5.5-6.9 m/s and the mixed layer depth was about 40 m in pre-typhoon period. So the extent of the SST drop was probably due to the moving speed of typhoon and the depth of the mixed layer. In addition, the region with the largest decline of the sea surface height anomaly can indicate the location where the maximum cooling occurs.
Category 5 typhoon Megi was the most intense typhoon in 2010 of the world. It lingered in the South China Sea (SCS) for 5 d and caused a significant phytoplankton bloom detected by the satellite image. In this study, the authors investigated the ocean biological and physical responses to typhoon Megi by using chlorophyll-a (chl-a) concentration, sea surface temperature (SST), sea surface height anomaly (SSHA), sea surface wind measurements derived from different satellites and in situ data. The chl-a concentration (>3 mg/m3) increased thirty times in the SCS after the typhoon passage in comparison with the mean level of October averaged from 2002 to 2009. With the relationship of wind stress curl and upwelling, the authors found that the speed of upwelling was over ten times during typhoon than pre-typhoon period. Moreover, the mixed layer deepened about 20 m. These reveal that the enhancement of chl-a concentration was triggered by strong vertical mixing and upwelling. Along the track of typhoon, the maximum sea surface cooling (6-8℃) took place in the SCS where the moving speed of typhoon was only 1.4-2.8 m/s and the mixed layer depth was about 20 m in pre-typhoon period. However, the SST drop at the east of the Philippines is only 1-2℃ where the translation speed of typhoon was 5.5-6.9 m/s and the mixed layer depth was about 40 m in pre-typhoon period. So the extent of the SST drop was probably due to the moving speed of typhoon and the depth of the mixed layer. In addition, the region with the largest decline of the sea surface height anomaly can indicate the location where the maximum cooling occurs.
2012, (1): 59-65.
doi: 10.1007/s13131-012-0176-1
Abstract:
Marine airborne multispectrum scanner (MAMS) onboard the China marine surveillance plane can be used to survey marine environment, resources and disaster and provide the technical support for high-frequency, high-efficiency and high-resolution remote sensing monitoring for the coastal management. MAMS did not have the IMU/POS equipment, so it brought severe challenge for the geometry correction. One airborne geometry correction method is introduced for marine multispectrum data without the attitude information. First, it is the coarse geometry correction, which simulates the roll angle and pitch angle of plane according to the ideal flying model; the second step is the precise geometry correction by using the SPOT orthogonal projected data as the reference of registration, based on maximization of alignment metric method. With the validation, relative error of coarse correction is 81.42 m compared with SPOT data, and 11.3 m for precise correction. This method provides the high precision localization information for the oceanic remote sensing and application, and establishes the foundation for monitoring the marine resource and environment.
Marine airborne multispectrum scanner (MAMS) onboard the China marine surveillance plane can be used to survey marine environment, resources and disaster and provide the technical support for high-frequency, high-efficiency and high-resolution remote sensing monitoring for the coastal management. MAMS did not have the IMU/POS equipment, so it brought severe challenge for the geometry correction. One airborne geometry correction method is introduced for marine multispectrum data without the attitude information. First, it is the coarse geometry correction, which simulates the roll angle and pitch angle of plane according to the ideal flying model; the second step is the precise geometry correction by using the SPOT orthogonal projected data as the reference of registration, based on maximization of alignment metric method. With the validation, relative error of coarse correction is 81.42 m compared with SPOT data, and 11.3 m for precise correction. This method provides the high precision localization information for the oceanic remote sensing and application, and establishes the foundation for monitoring the marine resource and environment.
2012, (1): 66-72.
doi: 10.1007/s13131-012-0177-0
Abstract:
In the central Bohai Sea, both historical data and in situ observations show that the distribution of high chlorophyll concentration is consistent with warm water. The previous studies confirm that the warm water is caused by a joint effect of wave and tidal mixing. In this paper, the authors have coupled the Princeton ocean model (POM) with a biochemical model to further investigate the formation of the high chlorophyll concentration. When the wave mixing is excluded, the water temperature is lower and the chlorophyll concentration is also lower than the observation. However, if the wave mixing is included, strong wave mixing in the upper layer brings the warm water downward and nutrients upward so that both temperature and nutrients tend to be uniformly high from the surface to the bottom. This provides an environment which is favorable for the growth of the phytoplankton. Therefore the chlorophyll concentration, as a symbol of phytoplankton, shows high value in the central Bohai Sea. In conclusion, the wave mixing plays an important role in the formation of high chlorophyll concentration in the central Bohai Sea.
In the central Bohai Sea, both historical data and in situ observations show that the distribution of high chlorophyll concentration is consistent with warm water. The previous studies confirm that the warm water is caused by a joint effect of wave and tidal mixing. In this paper, the authors have coupled the Princeton ocean model (POM) with a biochemical model to further investigate the formation of the high chlorophyll concentration. When the wave mixing is excluded, the water temperature is lower and the chlorophyll concentration is also lower than the observation. However, if the wave mixing is included, strong wave mixing in the upper layer brings the warm water downward and nutrients upward so that both temperature and nutrients tend to be uniformly high from the surface to the bottom. This provides an environment which is favorable for the growth of the phytoplankton. Therefore the chlorophyll concentration, as a symbol of phytoplankton, shows high value in the central Bohai Sea. In conclusion, the wave mixing plays an important role in the formation of high chlorophyll concentration in the central Bohai Sea.
2012, (1): 73-82.
doi: 10.1007/s13131-012-0178-z
Abstract:
The influence of macronitrogen (NO3- and NH4+) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p (CO2) and HCO3- concentration decrease significantly, while pH and CO32- concentration increase significantly. When the concentration of NO3- was less than 71 μmol/dm3 or NH4+ was less than 49.7 μmol/dm3, dissolved inorganic carbon (DIC) absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm3 with the addition of 71 μmol/dm3 NO3- and decreased 232 μmol/dm3 with the addition of 49.7 μmol/dm3 NH4+ after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between △c (DIC) and growth rate (μ) of Ulva pertusa (r=-0.91, P <0.000 1, n=11). NH4+ had more influence on the species of inorganic carbon system than NO3-.
The influence of macronitrogen (NO3- and NH4+) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p (CO2) and HCO3- concentration decrease significantly, while pH and CO32- concentration increase significantly. When the concentration of NO3- was less than 71 μmol/dm3 or NH4+ was less than 49.7 μmol/dm3, dissolved inorganic carbon (DIC) absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm3 with the addition of 71 μmol/dm3 NO3- and decreased 232 μmol/dm3 with the addition of 49.7 μmol/dm3 NH4+ after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between △c (DIC) and growth rate (μ) of Ulva pertusa (r=-0.91, P <0.000 1, n=11). NH4+ had more influence on the species of inorganic carbon system than NO3-.
2012, (1): 83-94.
doi: 10.1007/s13131-012-0179-y
Abstract:
The late Quaternary paleoceanographic changes in the western Arctic Ocean are revealed by quantitative studies of foraminiferal abundance, ice-rafted detritus (IRD) and its mineralogical and petrological compositions, planktonic Neogloboquadrina pachyderma (sin.) (Nps)-δ18O and -δ13C, biogenic and non-biogenic components in Core M03 token from the Chukchi Basin during the Second Chinese National Arctic Expedition cruise. Seven IRD events appeared at MIS 7, 5, 3 and 1. These IRD were carried in massive icebergs, which were exported to the Beaufort Sea through the M'Clure Strait Ice Stream, Canadian Arctic Archipelago, and then transported into the Chukchi Basin by the Beaufort Gyre. Low IRD deposition occurred during the glacial times when more extended ice cover and weakened Beaufort Gyre, while the open water condition and the intensified Beaufort Gyre during interglacial periods favored the IRD deposition. Therefore, the IRD events not only indicate the provenance of coarser detritus and ice export events, but also reflect the evolutionary histories of the Beaufort Gyre and North American ice sheet. Seven light Nps-δ18O and -δ13C excursions could respond to enhanced rates of sea ice formation resulting in the production and sinking of isotopically light brines, but was irrelevant to the warm Atlantic water and freshwater inputs. Whereas, the heavy Nps-δ18O and -δ13C values separately reflect the lessened Arctic freshwater and Pacific water, and well-ventilated surface water from the continental shelf and halocline water. Variations of CaCO3 content and planktonic foraminiferal abundance during the interglacial and glacial periods can demonstrate the incremental or diminishing input of the Atlantic water, while the total organic carbon (TOC) and opal contents increased and decreased during the glacial and interglacial periods, respectively, which could be related to the TOC degradation, opal dissolution and redox conditions of interface between the bottom water and sediments.
The late Quaternary paleoceanographic changes in the western Arctic Ocean are revealed by quantitative studies of foraminiferal abundance, ice-rafted detritus (IRD) and its mineralogical and petrological compositions, planktonic Neogloboquadrina pachyderma (sin.) (Nps)-δ18O and -δ13C, biogenic and non-biogenic components in Core M03 token from the Chukchi Basin during the Second Chinese National Arctic Expedition cruise. Seven IRD events appeared at MIS 7, 5, 3 and 1. These IRD were carried in massive icebergs, which were exported to the Beaufort Sea through the M'Clure Strait Ice Stream, Canadian Arctic Archipelago, and then transported into the Chukchi Basin by the Beaufort Gyre. Low IRD deposition occurred during the glacial times when more extended ice cover and weakened Beaufort Gyre, while the open water condition and the intensified Beaufort Gyre during interglacial periods favored the IRD deposition. Therefore, the IRD events not only indicate the provenance of coarser detritus and ice export events, but also reflect the evolutionary histories of the Beaufort Gyre and North American ice sheet. Seven light Nps-δ18O and -δ13C excursions could respond to enhanced rates of sea ice formation resulting in the production and sinking of isotopically light brines, but was irrelevant to the warm Atlantic water and freshwater inputs. Whereas, the heavy Nps-δ18O and -δ13C values separately reflect the lessened Arctic freshwater and Pacific water, and well-ventilated surface water from the continental shelf and halocline water. Variations of CaCO3 content and planktonic foraminiferal abundance during the interglacial and glacial periods can demonstrate the incremental or diminishing input of the Atlantic water, while the total organic carbon (TOC) and opal contents increased and decreased during the glacial and interglacial periods, respectively, which could be related to the TOC degradation, opal dissolution and redox conditions of interface between the bottom water and sediments.
2012, (1): 95-97.
doi: 10.1007/s13131-012-0180-5
Abstract:
One new species of free-living marine nematode Cephalanticoma brevicaudata sp. nov. from the South China Sea is described. Cephalanticoma brevicaudata sp. nov. is characterized by spindle body with relatively short tail; head with cephalic capsule; three teeth at anterior of pharynx; excretory pore opens posterior to cervical setae; three cervical setae per file; spicules arcuate, cephalate and ventrally bent proximally, and blunt distally, 1.8 a.b.d. long, without ventral ala; gubernaculun slender, simple rod, without apophyses; tubular supplement 34 μm long, 2.3 a.b.d. in front of cloaca.
One new species of free-living marine nematode Cephalanticoma brevicaudata sp. nov. from the South China Sea is described. Cephalanticoma brevicaudata sp. nov. is characterized by spindle body with relatively short tail; head with cephalic capsule; three teeth at anterior of pharynx; excretory pore opens posterior to cervical setae; three cervical setae per file; spicules arcuate, cephalate and ventrally bent proximally, and blunt distally, 1.8 a.b.d. long, without ventral ala; gubernaculun slender, simple rod, without apophyses; tubular supplement 34 μm long, 2.3 a.b.d. in front of cloaca.
2012, (1): 98-105.
doi: 10.1007/s13131-012-0181-4
Abstract:
This study contributes with the first data on physical and taxonomical structure of macrofaunal assemblages of maërl beds from the Canary Islands. Maërl beds and Cymodocea nodosa meadows of the Canary Islands are considered biodiversity hot-spots in terms of taxonomic and functional biodiversity with a broad geographical and depth ranges. The authors have studied the structure of the macrofaunal assemblages on different habitat types (Cymodocea, Caulerpa, sabellid field, garden eel and maërl beds). Samples were taken at a range of depths between 14 and 46 m. Correlations were performed among abiotic variables (granulometry, organic matter, nitrogen and phosphates) and the most abundant taxa. Similarity analysis was performed to explore the patchiness of seabeds at a local scale. Significant differences were found in macrofaunal assemblages among seabed types, with highest abundances and lowest biodiversity in sabellid fields, where the sabellid Bispira viola dominated. The polychaetes Aponuphis bilineata and Chone filicauda and the mollusc Turritella brochii were the most abundant taxa on maërl beds. The mosaic of granulometric conditions would explain the associated macroinfaunal community structure and contribute to the creation of diversity on these relatively well preserved seabeds at a local scale.
This study contributes with the first data on physical and taxonomical structure of macrofaunal assemblages of maërl beds from the Canary Islands. Maërl beds and Cymodocea nodosa meadows of the Canary Islands are considered biodiversity hot-spots in terms of taxonomic and functional biodiversity with a broad geographical and depth ranges. The authors have studied the structure of the macrofaunal assemblages on different habitat types (Cymodocea, Caulerpa, sabellid field, garden eel and maërl beds). Samples were taken at a range of depths between 14 and 46 m. Correlations were performed among abiotic variables (granulometry, organic matter, nitrogen and phosphates) and the most abundant taxa. Similarity analysis was performed to explore the patchiness of seabeds at a local scale. Significant differences were found in macrofaunal assemblages among seabed types, with highest abundances and lowest biodiversity in sabellid fields, where the sabellid Bispira viola dominated. The polychaetes Aponuphis bilineata and Chone filicauda and the mollusc Turritella brochii were the most abundant taxa on maërl beds. The mosaic of granulometric conditions would explain the associated macroinfaunal community structure and contribute to the creation of diversity on these relatively well preserved seabeds at a local scale.
2012, (1): 106-115.
doi: 10.1007/s13131-012-0182-3
Abstract:
A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism (RLO), was frequently found in the moribund or dead blood clam sample during ultrastructural examination. These organisms were usually round, ellipsoid or occasionally dumbbellshaped, ranged from approximately 0.28 to 0.71 μm in size and had a trilaminar cell wall. Two reproductive modes of organisms, transverse binary fission and budding, were observed. The organisms were able to form eosinophilic inclusions. Most inclusions were found within epithelial and connective tissues of the mantle, gills and digestive tube. The biological and morphological characteristics indicate that these organisms may belong to the family Rickettsiaceae. RLOs exhibited significant pathogenicity. Cytopathological examinations revealed extensive necrosis and destruction in the infected cell. The degree of tissue destruction was positively related to the number of RLO inclusions in the tissues, and the cytopathological effects were positively related to the number of intracellular RLO. RLOs and their inclusions were discovered throughout different disease areas and in different time periods. The infection intensity of the RLOs was positively correlated with the mortality rate of clams. Therefore, RLO infection might be associated with mass mortalities of cultured blood clams in the Yueqing Bay.
A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism (RLO), was frequently found in the moribund or dead blood clam sample during ultrastructural examination. These organisms were usually round, ellipsoid or occasionally dumbbellshaped, ranged from approximately 0.28 to 0.71 μm in size and had a trilaminar cell wall. Two reproductive modes of organisms, transverse binary fission and budding, were observed. The organisms were able to form eosinophilic inclusions. Most inclusions were found within epithelial and connective tissues of the mantle, gills and digestive tube. The biological and morphological characteristics indicate that these organisms may belong to the family Rickettsiaceae. RLOs exhibited significant pathogenicity. Cytopathological examinations revealed extensive necrosis and destruction in the infected cell. The degree of tissue destruction was positively related to the number of RLO inclusions in the tissues, and the cytopathological effects were positively related to the number of intracellular RLO. RLOs and their inclusions were discovered throughout different disease areas and in different time periods. The infection intensity of the RLOs was positively correlated with the mortality rate of clams. Therefore, RLO infection might be associated with mass mortalities of cultured blood clams in the Yueqing Bay.
2012, (1): 116-124.
doi: 10.1007/s13131-012-0183-2
Abstract:
Antarctic ice microalga can survive and thrive in channels or pores containing high salinity in Antarctic ice layer. In this study, it was found that cell membrane permeability of green microalga Chlamydomonas sp. L4 from Antarctic sea ice was high in cells treated with hypersalinity due to the induction of active oxygen and radicals. However, increased super oxide dismutase (SOD) scavenged harmful free radicals effectively to keep cell membrane integrity. Also, the analysis of membrane fatty acids demonstrated the content of saturated fatty acids and monounsaturated fatty acids increased and polyunsaturated fatty acids decreased under the high-salt treatment for 14 d, which effectively reduced the membrane fluidity and minimized the injury to cell membrane. The morphological changes showed that hypersalinity induced the increase of cell volume and the consumption of starch granules. However, because of the increase in detoxification of vacuoles, electron-dense deposits and SOD activity under high-salt stress, the complete noninterference thylakoids, mitochondria and cell nucleus maintained cellular fundamental metabolism. Global-expression profiling of proteins showed eight protein spots disappeared, 18 protein spots decreased and 18 protein spots were enhanced after the high-salt shock obviously (P <0.05). One new peptide (pI 6.90; MW 51 kDa) was primarily confirmed as the processor of light reaction center protein CP43 in photosystem Ⅱ, which increased photosynthesis ability of Chlamydomonas sp. L4 treated with high salinity.
Antarctic ice microalga can survive and thrive in channels or pores containing high salinity in Antarctic ice layer. In this study, it was found that cell membrane permeability of green microalga Chlamydomonas sp. L4 from Antarctic sea ice was high in cells treated with hypersalinity due to the induction of active oxygen and radicals. However, increased super oxide dismutase (SOD) scavenged harmful free radicals effectively to keep cell membrane integrity. Also, the analysis of membrane fatty acids demonstrated the content of saturated fatty acids and monounsaturated fatty acids increased and polyunsaturated fatty acids decreased under the high-salt treatment for 14 d, which effectively reduced the membrane fluidity and minimized the injury to cell membrane. The morphological changes showed that hypersalinity induced the increase of cell volume and the consumption of starch granules. However, because of the increase in detoxification of vacuoles, electron-dense deposits and SOD activity under high-salt stress, the complete noninterference thylakoids, mitochondria and cell nucleus maintained cellular fundamental metabolism. Global-expression profiling of proteins showed eight protein spots disappeared, 18 protein spots decreased and 18 protein spots were enhanced after the high-salt shock obviously (P <0.05). One new peptide (pI 6.90; MW 51 kDa) was primarily confirmed as the processor of light reaction center protein CP43 in photosystem Ⅱ, which increased photosynthesis ability of Chlamydomonas sp. L4 treated with high salinity.
2012, (1): 125-133.
doi: 10.1007/s13131-012-0184-1
Abstract:
Beach nourishment is a common coastal management strategy used to protect beach from erosion along the sandy coastlines. This method has been successfully applied to an emergency project at the West Beach of Beidaihe in the summer of 2008 and the full West Beach nourishment project in 2009-2010, which is the direct base of this study. Some basic information about the emergency engineering area at the Middle Beach is firstly described. The shoreline change of this area, including the analysis of beach width in five monitoring profiles in the bathing places of Middle Beach, is then discussed. After that a numerical model based on one-line theory is established and the numerical results agree well with the measured shorelines, which indicates that the model is appropriate and is qualified to predict the shoreline change of the Middle Beach. With the same model and parameters, long-term performance of the project is predicted, and the result shows that without follow-up nourishment and project, the bathing places can remain suitable for bathing for about 10 a. It is suggested to nourish the beach in time and carry out the beach nourishment project for the full Middle Beach in Beidaihe.
Beach nourishment is a common coastal management strategy used to protect beach from erosion along the sandy coastlines. This method has been successfully applied to an emergency project at the West Beach of Beidaihe in the summer of 2008 and the full West Beach nourishment project in 2009-2010, which is the direct base of this study. Some basic information about the emergency engineering area at the Middle Beach is firstly described. The shoreline change of this area, including the analysis of beach width in five monitoring profiles in the bathing places of Middle Beach, is then discussed. After that a numerical model based on one-line theory is established and the numerical results agree well with the measured shorelines, which indicates that the model is appropriate and is qualified to predict the shoreline change of the Middle Beach. With the same model and parameters, long-term performance of the project is predicted, and the result shows that without follow-up nourishment and project, the bathing places can remain suitable for bathing for about 10 a. It is suggested to nourish the beach in time and carry out the beach nourishment project for the full Middle Beach in Beidaihe.
2012, (1): 134-142.
doi: 10.1007/s13131-012-0185-0
Abstract:
Using a flow cytometer (FCM) onboard the R/V Xuelong during the 24th Chinese Antarctic cruise, picoplankton community structure and biomass in the surface water were examined along the latitude and around the Antarctic Ocean. Salinity and temperature were automatically recorded and total Chl a was determined. Along the cruise, the abundance of Synechococcus, Prochlorococcus, pico-eukaryotes and heterotrophic bacteria ranged in 0.001-1.855×108 ind./L, 0.000-2.778×108 ind./L, 0.002-1.060×108 ind./L and 0.132-27.073×108 ind./L, respectively. Major oceanic distribution of Synechococcus and Prochlorococcus appeared between latitudes 30°N and 30°S. Prochlorococcus was mainly influenced by water temperature, water mass combination and freshwater inflow. Meanwhile, Synechococcus distribution was significantly associated with landing freshwater inflow. Pico-eukaryotes and heterotrophic bacteria were distributed all over the oceans, but with a relatively low abundance in the high latitudes of the Antarctic Ocean. Principal Component Analysis showed that at same latitude of Atlantic Ocean and Indian Ocean, picoplankton distribution and constitution were totally different, geographical location and different water masses combination would be main reasons.
Using a flow cytometer (FCM) onboard the R/V Xuelong during the 24th Chinese Antarctic cruise, picoplankton community structure and biomass in the surface water were examined along the latitude and around the Antarctic Ocean. Salinity and temperature were automatically recorded and total Chl a was determined. Along the cruise, the abundance of Synechococcus, Prochlorococcus, pico-eukaryotes and heterotrophic bacteria ranged in 0.001-1.855×108 ind./L, 0.000-2.778×108 ind./L, 0.002-1.060×108 ind./L and 0.132-27.073×108 ind./L, respectively. Major oceanic distribution of Synechococcus and Prochlorococcus appeared between latitudes 30°N and 30°S. Prochlorococcus was mainly influenced by water temperature, water mass combination and freshwater inflow. Meanwhile, Synechococcus distribution was significantly associated with landing freshwater inflow. Pico-eukaryotes and heterotrophic bacteria were distributed all over the oceans, but with a relatively low abundance in the high latitudes of the Antarctic Ocean. Principal Component Analysis showed that at same latitude of Atlantic Ocean and Indian Ocean, picoplankton distribution and constitution were totally different, geographical location and different water masses combination would be main reasons.
