2010 Vol. 29, No. 5
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2010, 29(5): 1-9.
doi: 10.1007/s13131-010-0057-4
Abstract:
Altimeter and in situ data are used to estimate the mean surface zonal geostrophic current in the section along 115°E in the southern Indian Ocean, and the variation of strong currents in relation to the major fronts is studied. The results show that, in average, the flow in the core of Antarctic Circumpolar Current (ACC) along the section is composed of two parts, one corresponds to the jet of Subantarctic Front (SAF) and the other is the flow in the Polar Front Zone (PFZ), with a westward flow between them. The mean surface zonal geostrophic current corresponding to the SAF is up to 49 cm·s-1 at 46°S, which is the maximal velocity in the section. The eastward flow in the PFZ has a width of about 4.3 degrees in latitudes. The mean surface zonal geostrophic current corresponding to the Southern Antarctic Circumpolar Current Front (SACCF) is located at 59.7°S with velocity less than 20 cm·s-1. The location of zonal geostrophic jet corresponding to the SAF is quite stable during the study period. In contrast, the eastward jets in the PFZ exhibit various patterns, i.e., the primary Polar Front (PF1) shows its strong meridional shift and the secondary Polar Front (PF2) does not always coincide with jet. The surface zonal geostrophic current corresponding to SAF has the significant periods of annual, semi-annual and four-month. The geostrophic current of the PFZ also shows significant periods of semi-annual and four-month, but is out of phase with the periods of the SAF, which results in no notable semi-annual and fourmonth periods in the surface zonal geostrophic current in the core of the ACC. In terms of annual cycle, the mean surface zonal geostrophic current in the core of the ACC shows its maximal velocity in June.
Altimeter and in situ data are used to estimate the mean surface zonal geostrophic current in the section along 115°E in the southern Indian Ocean, and the variation of strong currents in relation to the major fronts is studied. The results show that, in average, the flow in the core of Antarctic Circumpolar Current (ACC) along the section is composed of two parts, one corresponds to the jet of Subantarctic Front (SAF) and the other is the flow in the Polar Front Zone (PFZ), with a westward flow between them. The mean surface zonal geostrophic current corresponding to the SAF is up to 49 cm·s-1 at 46°S, which is the maximal velocity in the section. The eastward flow in the PFZ has a width of about 4.3 degrees in latitudes. The mean surface zonal geostrophic current corresponding to the Southern Antarctic Circumpolar Current Front (SACCF) is located at 59.7°S with velocity less than 20 cm·s-1. The location of zonal geostrophic jet corresponding to the SAF is quite stable during the study period. In contrast, the eastward jets in the PFZ exhibit various patterns, i.e., the primary Polar Front (PF1) shows its strong meridional shift and the secondary Polar Front (PF2) does not always coincide with jet. The surface zonal geostrophic current corresponding to SAF has the significant periods of annual, semi-annual and four-month. The geostrophic current of the PFZ also shows significant periods of semi-annual and four-month, but is out of phase with the periods of the SAF, which results in no notable semi-annual and fourmonth periods in the surface zonal geostrophic current in the core of the ACC. In terms of annual cycle, the mean surface zonal geostrophic current in the core of the ACC shows its maximal velocity in June.
2010, 29(5): 10-20.
doi: 10.1007/s13131-010-0058-3
Abstract:
By using the Arctic runoff data from R-ArcticNET V4.0 and ArcticRIMS, trends of four major rivers flowing into the Arctic Ocean, whose climate factor plays an important role in determining the variability of the Arctic runoff, are investigated. The results show that for the past 30 years, the trend of the Arctic runoff is seasonally dependent. There is a significant trend in spring and winter and a significant decreasing trend in summer, leading to the reduced seasonal cycle. In spring, surface air temperature is the dominant factor influencing the four rivers. In summer, precipitation is the most important factor for Lena and Mackenzie, while snow cover is the most important factor for Yenisei and Ob. For Mackenzie, atmospheric circulation does play an important role for all the seasons, which is not the case for the Eurasian rivers. The authors further discuss the relationships between the Arctic runoff and sea ice. Significant negative correlation is found at the mouth of the rivers into the Arctic Ocean in spring, while significant positive correlation is observed just at the north of the mouths of the rivers into the Arctic in summer. In addition, each river has different relationship with sea ice in the eastern Greenland Sea.
By using the Arctic runoff data from R-ArcticNET V4.0 and ArcticRIMS, trends of four major rivers flowing into the Arctic Ocean, whose climate factor plays an important role in determining the variability of the Arctic runoff, are investigated. The results show that for the past 30 years, the trend of the Arctic runoff is seasonally dependent. There is a significant trend in spring and winter and a significant decreasing trend in summer, leading to the reduced seasonal cycle. In spring, surface air temperature is the dominant factor influencing the four rivers. In summer, precipitation is the most important factor for Lena and Mackenzie, while snow cover is the most important factor for Yenisei and Ob. For Mackenzie, atmospheric circulation does play an important role for all the seasons, which is not the case for the Eurasian rivers. The authors further discuss the relationships between the Arctic runoff and sea ice. Significant negative correlation is found at the mouth of the rivers into the Arctic Ocean in spring, while significant positive correlation is observed just at the north of the mouths of the rivers into the Arctic in summer. In addition, each river has different relationship with sea ice in the eastern Greenland Sea.
2010, 29(5): 21-26.
doi: 10.1007/s13131-010-0059-2
Abstract:
Theoretical analysis and numerical simulation have been applied to researching the effect of wave, current and wind on the ice rafting. The analytical results show that wave is the key factor for ice fracture. The process of ice rafting is simulated using the discrete element method. The simulated results show that the distortion or flexure breakage happens firstly, then followed by ice rafting. The comprehensively analysed results show that the ice is easily rafted on the simultaneity action of wave, current and wind, and the action of wave can't be ignored. Moreover, the rafted ice length increases with the enhancive force of ocean current and wind.
Theoretical analysis and numerical simulation have been applied to researching the effect of wave, current and wind on the ice rafting. The analytical results show that wave is the key factor for ice fracture. The process of ice rafting is simulated using the discrete element method. The simulated results show that the distortion or flexure breakage happens firstly, then followed by ice rafting. The comprehensively analysed results show that the ice is easily rafted on the simultaneity action of wave, current and wind, and the action of wave can't be ignored. Moreover, the rafted ice length increases with the enhancive force of ocean current and wind.
2010, 29(5): 27-34.
doi: 10.1007/s13131-010-0060-9
Abstract:
The coastal ecosystem health assessment is a field of increasing importance. In this paper, a preliminary assessment of ecosystem health in Zhejiang coastal water zone was made, mainly based on remote sensing data and GIS technique. Its spatial and quantitative evaluation was facilitated by the progress of remote sensing and GIS technique development. Firstly, human activities, hydrology and ecosystem problems in the study area were discussed and analyzed. Secondly, from 4 aspects of human stress, physical, chemical and biological responses to anthropogenic activities and natural stress, several indicators such as water transparency (Secchi Disk Depth, SDD), suspended substance concentration, dissolved inorganic nitrogen, active phosphate, chlorophyll, harmful algae bloom, as well as distribution of sewage, sea lanes and port were employed. Thirdly, the Analytic Hierarchical Process was used for indicator weight calculation, and the ecosystem health criteria were established according to the integrative analysis of national water quality criteria, similar coastal ecosystem health research in other places or data inherent properties. The results indicated that from 2005 to 2007 the coastal water ecosystem health value in Zhejiang Province was unhealthy and needs ecological restoration by human intervention.
The coastal ecosystem health assessment is a field of increasing importance. In this paper, a preliminary assessment of ecosystem health in Zhejiang coastal water zone was made, mainly based on remote sensing data and GIS technique. Its spatial and quantitative evaluation was facilitated by the progress of remote sensing and GIS technique development. Firstly, human activities, hydrology and ecosystem problems in the study area were discussed and analyzed. Secondly, from 4 aspects of human stress, physical, chemical and biological responses to anthropogenic activities and natural stress, several indicators such as water transparency (Secchi Disk Depth, SDD), suspended substance concentration, dissolved inorganic nitrogen, active phosphate, chlorophyll, harmful algae bloom, as well as distribution of sewage, sea lanes and port were employed. Thirdly, the Analytic Hierarchical Process was used for indicator weight calculation, and the ecosystem health criteria were established according to the integrative analysis of national water quality criteria, similar coastal ecosystem health research in other places or data inherent properties. The results indicated that from 2005 to 2007 the coastal water ecosystem health value in Zhejiang Province was unhealthy and needs ecological restoration by human intervention.
Atmospheric frontal gravity waves observed in satellite SAR images of the Bohai Sea and Huanghai Sea
2010, 29(5): 35-43.
doi: 10.1007/s13131-010-0061-8
Abstract:
In the satellite synthetic aperture radar (SAR) images of the Bohai Sea and Huanghai Sea, the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km. Comparing SAR observations with sea surface wind fields and surface weather maps, the authors find that the occurrence of the wave-like phenomena is associated with the passing of atmospheric front. The authors define the waves as atmospheric frontal gravity waves. The dynamical parameters of the wave packets are derived from statistics of 9 satellite SAR images obtained from 2002 to 2008. A two-dimensional linear physical wave model is used to analyze the generation mechanism of the waves. The atmospheric frontal wave induced wind variation across the frontal wave packet is compared with wind retrievals from the SAR images. The CMOD-5 (C-band scatterometer ocean geophysical model function) is used for SAR wind retrievals VV (transmitted vertical and received vertical) for ENVISAT and HH (transmitted horizontally and received horizontally) for RADARSAT-1. A reasonable agreement between the analytical solution and the SAR observation is reached. This new SAR frontal wave observation adds to the school of SAR observations of sea surface imprints of AGWs including island lee waves, coastal lee waves, and upstream Atmospheric Gravity Waves (AGW).
In the satellite synthetic aperture radar (SAR) images of the Bohai Sea and Huanghai Sea, the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km. Comparing SAR observations with sea surface wind fields and surface weather maps, the authors find that the occurrence of the wave-like phenomena is associated with the passing of atmospheric front. The authors define the waves as atmospheric frontal gravity waves. The dynamical parameters of the wave packets are derived from statistics of 9 satellite SAR images obtained from 2002 to 2008. A two-dimensional linear physical wave model is used to analyze the generation mechanism of the waves. The atmospheric frontal wave induced wind variation across the frontal wave packet is compared with wind retrievals from the SAR images. The CMOD-5 (C-band scatterometer ocean geophysical model function) is used for SAR wind retrievals VV (transmitted vertical and received vertical) for ENVISAT and HH (transmitted horizontally and received horizontally) for RADARSAT-1. A reasonable agreement between the analytical solution and the SAR observation is reached. This new SAR frontal wave observation adds to the school of SAR observations of sea surface imprints of AGWs including island lee waves, coastal lee waves, and upstream Atmospheric Gravity Waves (AGW).
2010, 29(5): 44-51.
doi: 10.1007/s13131-010-0062-7
Abstract:
Nonylphenol (NP) and bisphenol A (BPA) are endocrine disruptors causing harmful effects including feminization and carcinogenesis to various organisms, and consequently, their contamination in natural environment has received wide concerns. This study reports the distribution characteristics of NP and BPA in surface sediments and their deposition history based on a dated sediment core in the Changjiang River (Yangtze River) Estuary and its adjacent East China Sea. The contents of NP and BPA in surface sediments ranged from 1.56-35.8 and 0.72-13.2 ng/g (dry mass), respectively, with high values recorded in the two mud zones, the Changjiang River Estuarine Mud Zone and the Zhejiang Coastal Mud Zone. High values in the Zhejiang Coastal Mud Zone suggest the possibility of long distance transport of both contaminants through the Changjiang riverine plume. The contents were not correlated with the distance from the pollution source, indicating other factors including particle deposition rate and sediment grain size obviously affecting the distribution pattern. NP was also detected in a sediment core at layers deposited from the year of 1971 to 2001 with contents of up to 20.9 ng/g (dry mass). The deposition fluxes of NP varied from 0.68 to 17.9 ng/(cm2·a) with peaks and valleys reflecting the traces of economic development history in China during the previous three decades. BPA was detected at sediment layers deposited from 1973 to 2001 with contents of up to 3.66 ng/g. The fluxes of BPA varied from 0.62 to 3.13 ng/(cm2·a) showing a similar pattern as NP. The contents of NP and BPA also indicated potential risks on benthic organisms in the study area.
Nonylphenol (NP) and bisphenol A (BPA) are endocrine disruptors causing harmful effects including feminization and carcinogenesis to various organisms, and consequently, their contamination in natural environment has received wide concerns. This study reports the distribution characteristics of NP and BPA in surface sediments and their deposition history based on a dated sediment core in the Changjiang River (Yangtze River) Estuary and its adjacent East China Sea. The contents of NP and BPA in surface sediments ranged from 1.56-35.8 and 0.72-13.2 ng/g (dry mass), respectively, with high values recorded in the two mud zones, the Changjiang River Estuarine Mud Zone and the Zhejiang Coastal Mud Zone. High values in the Zhejiang Coastal Mud Zone suggest the possibility of long distance transport of both contaminants through the Changjiang riverine plume. The contents were not correlated with the distance from the pollution source, indicating other factors including particle deposition rate and sediment grain size obviously affecting the distribution pattern. NP was also detected in a sediment core at layers deposited from the year of 1971 to 2001 with contents of up to 20.9 ng/g (dry mass). The deposition fluxes of NP varied from 0.68 to 17.9 ng/(cm2·a) with peaks and valleys reflecting the traces of economic development history in China during the previous three decades. BPA was detected at sediment layers deposited from 1973 to 2001 with contents of up to 3.66 ng/g. The fluxes of BPA varied from 0.62 to 3.13 ng/(cm2·a) showing a similar pattern as NP. The contents of NP and BPA also indicated potential risks on benthic organisms in the study area.
2010, 29(5): 52-64.
doi: 10.1007/s13131-010-0063-6
Abstract:
The present study is based on the sedimentological data from a piston core KCES1 off the southern Ulleung Basin margin, the East Sea (Sea of Japan). The data include sediment color (L*), X-ray radiographs, grain size distribution and AMS14C date. Four kinds of sediments (homogeneous, laminated, crudely laminated and hybrid sediments) are identified according to the characters of the sedimentary structures that were considered to reflect changes in bottom-water oxygenation. Alternations of dark laminated/crudely laminated sediments and light homogeneous sediments represent millennial-scale variations that are possibly associated with the high-resolution changes in the East Asian monsoon (EAM). The relative contributions of the East China Sea Coastal Water (ECSCW) and the Tsushima Warm Current (TWC) were likely the main reasons for the repetition of the anoxic and oxic depositional conditions in the East Sea since the last 48 ka BP. During the interstadial, the strengthen summer EAM was attributed to the expansion of the ECSCW because of more humid climate in central Asia, and then more strongly low-salinity, nutrient-enriched water was introduced into the East Sea. The ventilation of deep water was restricted and therefore the dark laminated layer deposited under the anoxic bottom water condition. During the lowest stand of sea level in the last glacial maximum (LGM), the isolated East Sea dominated by stratified water masses and the euxinic depositional environment formed. The homogenous sediments have been predominating since 17.5 ka BP indicating that the TWC has intruded into the East Sea gradually with the stepwise rise of sea level and the bottom water oxygen level was high. During the late Younger Dryas (YD) period, the last dark laminated layer deposited because the ventilation of bottom water was restricted by stronger summer EAM. The TWC strengthened and the bottom water became oxic again from 10.5 ka BP.
The present study is based on the sedimentological data from a piston core KCES1 off the southern Ulleung Basin margin, the East Sea (Sea of Japan). The data include sediment color (L*), X-ray radiographs, grain size distribution and AMS14C date. Four kinds of sediments (homogeneous, laminated, crudely laminated and hybrid sediments) are identified according to the characters of the sedimentary structures that were considered to reflect changes in bottom-water oxygenation. Alternations of dark laminated/crudely laminated sediments and light homogeneous sediments represent millennial-scale variations that are possibly associated with the high-resolution changes in the East Asian monsoon (EAM). The relative contributions of the East China Sea Coastal Water (ECSCW) and the Tsushima Warm Current (TWC) were likely the main reasons for the repetition of the anoxic and oxic depositional conditions in the East Sea since the last 48 ka BP. During the interstadial, the strengthen summer EAM was attributed to the expansion of the ECSCW because of more humid climate in central Asia, and then more strongly low-salinity, nutrient-enriched water was introduced into the East Sea. The ventilation of deep water was restricted and therefore the dark laminated layer deposited under the anoxic bottom water condition. During the lowest stand of sea level in the last glacial maximum (LGM), the isolated East Sea dominated by stratified water masses and the euxinic depositional environment formed. The homogenous sediments have been predominating since 17.5 ka BP indicating that the TWC has intruded into the East Sea gradually with the stepwise rise of sea level and the bottom water oxygen level was high. During the late Younger Dryas (YD) period, the last dark laminated layer deposited because the ventilation of bottom water was restricted by stronger summer EAM. The TWC strengthened and the bottom water became oxic again from 10.5 ka BP.
2010, 29(5): 65-73.
doi: 10.1007/s13131-010-0064-5
Abstract:
It is well known that marine sponges harbor large numbers of bacteria, some of which have been proved to be sponge-specific. The diversity of bacteria in marine sponges distributed along the coast of South China Sea has been previously studied but that of bacteria in sponges inhabiting the open sea has been rarely investigated. In this report, the diversity of bacteria associated with the marine sponge Agelas robusta from a remote coral reef in the South China Sea was documented employing 16S rDNA library construction, amplified ribosomal DNA restriction analysis (ARDRA) and phylogenetic analysis. A total of 32 phylotypes were finally categorized in nine phyla including Cyanobacteria, Proteobacteria, Chloroflexi, Firmicutes, Actinobacteria, Acidobacteria, Planctomycetes, Bacteroidetes and Gemmatimonadetes. The dominant phylum was Proteobacteria whereas the dominant genus was Synechococcus in Cyanobacteria. Some spongespecific bacteria were also found in the bacteria population, but the proportion (5 OTUs/32 OTUs) was much lower than other sponges. This study reveals the phylogenetic diversity of bacteria in A. robusta and confirms the presence of some sponge-specific bacteria in the South China Sea. Understanding the diversity of sponge-associated bacteria in China assists to exploit the bacteria resources for biotechnology.
It is well known that marine sponges harbor large numbers of bacteria, some of which have been proved to be sponge-specific. The diversity of bacteria in marine sponges distributed along the coast of South China Sea has been previously studied but that of bacteria in sponges inhabiting the open sea has been rarely investigated. In this report, the diversity of bacteria associated with the marine sponge Agelas robusta from a remote coral reef in the South China Sea was documented employing 16S rDNA library construction, amplified ribosomal DNA restriction analysis (ARDRA) and phylogenetic analysis. A total of 32 phylotypes were finally categorized in nine phyla including Cyanobacteria, Proteobacteria, Chloroflexi, Firmicutes, Actinobacteria, Acidobacteria, Planctomycetes, Bacteroidetes and Gemmatimonadetes. The dominant phylum was Proteobacteria whereas the dominant genus was Synechococcus in Cyanobacteria. Some spongespecific bacteria were also found in the bacteria population, but the proportion (5 OTUs/32 OTUs) was much lower than other sponges. This study reveals the phylogenetic diversity of bacteria in A. robusta and confirms the presence of some sponge-specific bacteria in the South China Sea. Understanding the diversity of sponge-associated bacteria in China assists to exploit the bacteria resources for biotechnology.
2010, 29(5): 74-81.
doi: 10.1007/s13131-010-0065-4
Abstract:
Considering that the field is largely unexplored and its importance to aquaculture, outline of oomycetes and fungi parasiting on marine algae was provided in this paper, including 15 species of oomycetes, six species of chytrids, 31 Ascomycota species and one species of mitosporic fungi. In natrue, both the oomycetes and chytrids frequently occurred and induced prevalences of disease which could destroy the populations of host plants greatly. However, the parasites in Ascomycota on algae have never occurred as epidemics so far. Some issues relating to the field were discussed such as performing tests to satisfy Koch's postulates, investigations of host specificity, interactions between host and parasite and the potential effects of environmental factors on occurrence of a disease, which are urgent in need of further investigations.
Considering that the field is largely unexplored and its importance to aquaculture, outline of oomycetes and fungi parasiting on marine algae was provided in this paper, including 15 species of oomycetes, six species of chytrids, 31 Ascomycota species and one species of mitosporic fungi. In natrue, both the oomycetes and chytrids frequently occurred and induced prevalences of disease which could destroy the populations of host plants greatly. However, the parasites in Ascomycota on algae have never occurred as epidemics so far. Some issues relating to the field were discussed such as performing tests to satisfy Koch's postulates, investigations of host specificity, interactions between host and parasite and the potential effects of environmental factors on occurrence of a disease, which are urgent in need of further investigations.
2010, 29(5): 82-89.
doi: 10.1007/s13131-010-0066-3
Abstract:
The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria (AAnPB) and their relatives, anaerobic anoxygenic phototrophic bacteria (AnAnPB) and nonphototrophic bacteria (NPB, which had high homology of 16S rDNA gene with AAnPB and fell into the same genus), and validate reliability and usefulness of farnesyl pyrophosphate synthase (FPPS) gene for the phylogenetic determination. FPPS genes with our modified primers and 16S rDNA genes with general primers, were amplified and sequenced or retrieved from GenBank database. In contrast to 16S rDNA gene phylogenetic tree, AAnPB were grouped into two clusters and one branch alone with no intermingling with NPB and AnAnPB in the tree constructed on FPPS. One branch of AAnPB, in both trees, was located closer to outgroup species than AnAnPB, which implicated that some AAnPB would be diverged earlier in FPPS evolutionary history than AnAnPB and NPB. Some AAnPB and NPB were closer located in both trees and this suggested that they were the closer relatives than AnAnPB. Combination codon usage in FPPS with phylogenetic analysis, the results indicates that FPPS gene and 16S rRNA gene have similar evolutionary pattern but the former seems to be more reliable and useful in determining the phylogenic and evolutionary relationship between AAnPB and their relatives. This is the first attempt to use a molecular marker beside 16S rRNA gene for studying the phylogeny of AAnPB, and the study may also be helpful in understanding the evolutionary relationship among phototrophic microbes and the trends of photosynthetic genes transfer.
The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria (AAnPB) and their relatives, anaerobic anoxygenic phototrophic bacteria (AnAnPB) and nonphototrophic bacteria (NPB, which had high homology of 16S rDNA gene with AAnPB and fell into the same genus), and validate reliability and usefulness of farnesyl pyrophosphate synthase (FPPS) gene for the phylogenetic determination. FPPS genes with our modified primers and 16S rDNA genes with general primers, were amplified and sequenced or retrieved from GenBank database. In contrast to 16S rDNA gene phylogenetic tree, AAnPB were grouped into two clusters and one branch alone with no intermingling with NPB and AnAnPB in the tree constructed on FPPS. One branch of AAnPB, in both trees, was located closer to outgroup species than AnAnPB, which implicated that some AAnPB would be diverged earlier in FPPS evolutionary history than AnAnPB and NPB. Some AAnPB and NPB were closer located in both trees and this suggested that they were the closer relatives than AnAnPB. Combination codon usage in FPPS with phylogenetic analysis, the results indicates that FPPS gene and 16S rRNA gene have similar evolutionary pattern but the former seems to be more reliable and useful in determining the phylogenic and evolutionary relationship between AAnPB and their relatives. This is the first attempt to use a molecular marker beside 16S rRNA gene for studying the phylogeny of AAnPB, and the study may also be helpful in understanding the evolutionary relationship among phototrophic microbes and the trends of photosynthetic genes transfer.
2010, 29(5): 90-96.
doi: 10.1007/s13131-010-0067-2
Abstract:
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.
2010, 29(5): 97-108.
doi: 10.1007/s13131-010-0068-1
Abstract:
The results of an investigation carried out during June 2005 to May 2007 on physico-chemical parameters, species composition and community structure of phytoplankton including Chlorophyll a (Chl-a) at the Coleroon coastal waters (Southeast coast of India) are reported. Air and surface water temperatures (℃) varied from 25.1 to 30.1 and from 24.5 to 28.5 respectively. Salinity values varied from 6 to 28.5 and the pH ranged between 7.0 and 8.3. Variation in dissolved oxygen content was from 3.1 to 7.5 mg/dm3 while the light extinction coefficient values (LEC) ranged between 3.1 and 10.1 cm. The ranges of inorganic nutrients (μmol/dm3) viz., nitrate, nitrite, phosphate and silicate were 10.1-23.4, 1.2-8.9, 0.2-3.1 and 55-125, respectively. The ranges of Chlorophyll a (μg/dm3) values was 2.0-7.5. Presently, 124 phytoplankton species representing different classes viz:Bacillariophyceae (77), Dinophyceae (19), Cyanophyceae (15), Chlorophyceae (10) and Chrysophyceae (3) were recorded. The phytoplankton cell abundance varied from 0.290 to 111.662 cells/cm3, with peak diversity (3.38 bits/ind.) during summer season. The maximum abundance was found during summer season coinciding with the stable hydrographical conditions. The seasonal distribution and abundance of phytoplankton are discussed in relation to hydrographical parameters. Canonical Correspondence Analysis (CCA) was applied in this paper for discriminating environmental factors having effect on phytoplankton community at species level. Coleroon coastal water is subjected to long term fluctuations in physico-chemical parameters depending upon the seasonal tidal amplitude and freshwater influx resulting in a continuous exchange of organic, inorganic, plant and animal matters.
The results of an investigation carried out during June 2005 to May 2007 on physico-chemical parameters, species composition and community structure of phytoplankton including Chlorophyll a (Chl-a) at the Coleroon coastal waters (Southeast coast of India) are reported. Air and surface water temperatures (℃) varied from 25.1 to 30.1 and from 24.5 to 28.5 respectively. Salinity values varied from 6 to 28.5 and the pH ranged between 7.0 and 8.3. Variation in dissolved oxygen content was from 3.1 to 7.5 mg/dm3 while the light extinction coefficient values (LEC) ranged between 3.1 and 10.1 cm. The ranges of inorganic nutrients (μmol/dm3) viz., nitrate, nitrite, phosphate and silicate were 10.1-23.4, 1.2-8.9, 0.2-3.1 and 55-125, respectively. The ranges of Chlorophyll a (μg/dm3) values was 2.0-7.5. Presently, 124 phytoplankton species representing different classes viz:Bacillariophyceae (77), Dinophyceae (19), Cyanophyceae (15), Chlorophyceae (10) and Chrysophyceae (3) were recorded. The phytoplankton cell abundance varied from 0.290 to 111.662 cells/cm3, with peak diversity (3.38 bits/ind.) during summer season. The maximum abundance was found during summer season coinciding with the stable hydrographical conditions. The seasonal distribution and abundance of phytoplankton are discussed in relation to hydrographical parameters. Canonical Correspondence Analysis (CCA) was applied in this paper for discriminating environmental factors having effect on phytoplankton community at species level. Coleroon coastal water is subjected to long term fluctuations in physico-chemical parameters depending upon the seasonal tidal amplitude and freshwater influx resulting in a continuous exchange of organic, inorganic, plant and animal matters.
2010, 29(5): 109-120.
doi: 10.1007/s13131-010-0069-0
Abstract:
A three-dimension ecological dynamic model was established to numerically study the relationship of HAB and environmental conditions. The numerical experiments showed that the growth of diatom, the dominant HAB specie, was mainly restricted by phosphate and silicate. If the concentrations of phosphate and silicate reach 17-25 μg/L and 300-375 μg/L respectively, the water is in a state of eutrophication. When phosphate and silicate up to 26-32 μg/L and 350-500 μg/L respectively, HAB could be induced. The major regions of HAB occurrence are Jiaozhou Bay mouth, coastal bays, and coastal area from Maidao to Shilaoren. To avoid HAB occurrence, concentration of phosphate and silicate should not exceed 17-20 μg/L and 300 μg/L as a whole. Reasonable control of pollutant discharge is a key point to prevent water eutrophication and HAB occurrence.
A three-dimension ecological dynamic model was established to numerically study the relationship of HAB and environmental conditions. The numerical experiments showed that the growth of diatom, the dominant HAB specie, was mainly restricted by phosphate and silicate. If the concentrations of phosphate and silicate reach 17-25 μg/L and 300-375 μg/L respectively, the water is in a state of eutrophication. When phosphate and silicate up to 26-32 μg/L and 350-500 μg/L respectively, HAB could be induced. The major regions of HAB occurrence are Jiaozhou Bay mouth, coastal bays, and coastal area from Maidao to Shilaoren. To avoid HAB occurrence, concentration of phosphate and silicate should not exceed 17-20 μg/L and 300 μg/L as a whole. Reasonable control of pollutant discharge is a key point to prevent water eutrophication and HAB occurrence.
Distribution and germination of viable diatom resting stage cells in sediments of the East China Sea
2010, 29(5): 121-128.
doi: 10.1007/s13131-010-0070-7
Abstract:
The abundance and temporal patterns of viable diatom resting stage cells in sediments of the East China Sea in 2006 have been investigated. The abundance of viable resting stages was enumerated with the most probable number (MPN) technique. Overall, 25 diatom species (including varieties) belonging to 16 genera were detected. Viable resting stage cells were common, on the order of 103 to 106 cells/g dry mass. The abundant taxa included Skeletonema marina, S. dohrnii, Chaetoceros curvisetus and Thalassiosira spp., with Skeletonema accounting for 83.3% of the cell. The effects of temperature (10, 15, 20, 25℃), salinity (20, 25, 30, 35 psu) and light intensity (0, 300, 4 000, 8 000 lux) on the germination of resting stages in sediment samples were also determined. The results showed that light intensity had a significant positive effect on the germination of diatom resting stage cells (p <0.01) and that diatoms could not germinate in darkness. Temperature and salinity had no noticeable effects on the germination. The present study suggests that there are abundant diatom resting cells in sediments of the East China Sea, which could serve as a "seed bank" in the phytoplankton population succession and contribute to the initiation of algal blooms.
The abundance and temporal patterns of viable diatom resting stage cells in sediments of the East China Sea in 2006 have been investigated. The abundance of viable resting stages was enumerated with the most probable number (MPN) technique. Overall, 25 diatom species (including varieties) belonging to 16 genera were detected. Viable resting stage cells were common, on the order of 103 to 106 cells/g dry mass. The abundant taxa included Skeletonema marina, S. dohrnii, Chaetoceros curvisetus and Thalassiosira spp., with Skeletonema accounting for 83.3% of the cell. The effects of temperature (10, 15, 20, 25℃), salinity (20, 25, 30, 35 psu) and light intensity (0, 300, 4 000, 8 000 lux) on the germination of resting stages in sediment samples were also determined. The results showed that light intensity had a significant positive effect on the germination of diatom resting stage cells (p <0.01) and that diatoms could not germinate in darkness. Temperature and salinity had no noticeable effects on the germination. The present study suggests that there are abundant diatom resting cells in sediments of the East China Sea, which could serve as a "seed bank" in the phytoplankton population succession and contribute to the initiation of algal blooms.
