2013 Vol. 35, No. 2
Display Method:
2013, 35(2): 1-8.
doi: 10.3969/j.issn.0253 4193.2013.02.001
Abstract:
Heterotrophic nanoflagellate (abbr., HNF) is the principal consumer of picoplankton in marine ecosystem. Recognizing its selective feeding impact is essential to evaluate the role of HNF in the marine microbial food web. Over the last few decades, there has been a concerted effort by many researchers to the understanding of selective grazing behaviors among HNF. This paper,(1) summarize current knowledge on factors affecting HNF selective feeding; (2) discuss mechanisms involved in HNF selective feeding; (3) review the influence of HNF selective feeding on the shape, size structure, taxonomic composition and physiological status of picoplankton communities.
Heterotrophic nanoflagellate (abbr., HNF) is the principal consumer of picoplankton in marine ecosystem. Recognizing its selective feeding impact is essential to evaluate the role of HNF in the marine microbial food web. Over the last few decades, there has been a concerted effort by many researchers to the understanding of selective grazing behaviors among HNF. This paper,(1) summarize current knowledge on factors affecting HNF selective feeding; (2) discuss mechanisms involved in HNF selective feeding; (3) review the influence of HNF selective feeding on the shape, size structure, taxonomic composition and physiological status of picoplankton communities.
2013, 35(2): 9-14.
doi: 10.3969/j.issn.0253 4193.2013.02.002
Abstract:
Based on the typhoon storm surge historical data of tide gauge stations, analyzing the simulation capabilities of the five remarkable typhoon storm surges by using the operational typhoon storm surge numerical model, results show that the model had well performance in simulating the storm surges which influenced the Ningbo region, especially for the peak surge. Therefore, taken the Zhenhai tide gauge station as the breakthrough point, used the tropical cyclone No.5612 (Wanda) which caused the biggest storm surge of Ningbo, shifted and then combined the different intensity level of tropical cyclones to build multiple hypothetical optimal tropical cyclones for the risk calculation of Ningbo region, to gain the probable maximum storm surge of five category that covered from the strong tropical storm to the super typhoon; moreover, the corresponding return period by using Pearson-Ⅲ distribution method was also carried out, the aim of the work is to provide the decision support for the effectively prevent various tropical cyclone storm surge in the future.
Based on the typhoon storm surge historical data of tide gauge stations, analyzing the simulation capabilities of the five remarkable typhoon storm surges by using the operational typhoon storm surge numerical model, results show that the model had well performance in simulating the storm surges which influenced the Ningbo region, especially for the peak surge. Therefore, taken the Zhenhai tide gauge station as the breakthrough point, used the tropical cyclone No.5612 (Wanda) which caused the biggest storm surge of Ningbo, shifted and then combined the different intensity level of tropical cyclones to build multiple hypothetical optimal tropical cyclones for the risk calculation of Ningbo region, to gain the probable maximum storm surge of five category that covered from the strong tropical storm to the super typhoon; moreover, the corresponding return period by using Pearson-Ⅲ distribution method was also carried out, the aim of the work is to provide the decision support for the effectively prevent various tropical cyclone storm surge in the future.
2013, 25(2): 15-20.
doi: 10.3969/j.issn.0253 4193.2013.02.003
Abstract:
Mean dynamic topography (MDT) is an important physical quantity of common concern from geodetic scientists and oceanographers. In this paper, WHU2009 mean sea surface height model and GO_CONS_GCF_2_TIM_R3 gravity field model which is derived from GOCE data are used to calculate global mean dynamic topography using pointwise approach after Gaussian filtering, compared with CLS09 and DTU10 MDTs, their root-mean-square values are less than 8 cm, which can indicate that the MDT model calculated in this paper has high accuracy. Its corresponding sea surface geostrophic current is determined by geostrophic current equation, compared with the sea surface geostrophic current from GGM03S gravity field model, the result from GOCE shows stronger current speed and finer details in Gulf Stream, Kuroshio Current and Agulhas Current regions, it can be proved that GOCE has more advantages in determining mean dynamic topography and sea surface geostrophic current than GRACE.
2013, 35(2): 21-34.
doi: 10.3969/j.issn.0253 4193.2013.02.004
Abstract:
Based on the 1951-2006 best tropical cyclone (TC) track dataset of the Joint Typhoon Warning Center (JJWC) and ENSO-related variables from the Climate Prediction Center (CPC). The relationship between northwestern Pacific accumulated cyclone energy (ACE) of different grades and ENSO are investigated. Results show that: ACE is positively correlated with ENSO indices. Among TC grades, Super-typhoon (SuperTY) contribute most to the relation between ENSO and ACE, the SuperTY amount is more and their lifetime are longer during El Niño episodes than those of La Niña ones. During the peak season of TC, the five-month lag correlation coefficient is almost as large as simultaneous correlation coefficient between the SuperTY ACE and ENSO indices. In addition, the contributions among annual mean TC lifetime, intensity, and amount of different TC grades related to the ENSO signal in ACE are compared, which suggest that the amount of SuperTY is the most important. Following, on the basis of the NCEP reanalysis data on different ENSO phases, the physical mechanism of the effect of ENSO on tropical cyclones of different degrees(especially the high intensity tropical cyclones), were also analyzed.It was concluded that there are some key zones in the Northwestern Pacific Ocean, where the number of the SuperTY in ENSO years is different from that in ordinary years. And ENSO events affect the genesis location and number of SuperTY mainly by changing the low-level relative vorticity and the sea surface temperature in some key zones.
Based on the 1951-2006 best tropical cyclone (TC) track dataset of the Joint Typhoon Warning Center (JJWC) and ENSO-related variables from the Climate Prediction Center (CPC). The relationship between northwestern Pacific accumulated cyclone energy (ACE) of different grades and ENSO are investigated. Results show that: ACE is positively correlated with ENSO indices. Among TC grades, Super-typhoon (SuperTY) contribute most to the relation between ENSO and ACE, the SuperTY amount is more and their lifetime are longer during El Niño episodes than those of La Niña ones. During the peak season of TC, the five-month lag correlation coefficient is almost as large as simultaneous correlation coefficient between the SuperTY ACE and ENSO indices. In addition, the contributions among annual mean TC lifetime, intensity, and amount of different TC grades related to the ENSO signal in ACE are compared, which suggest that the amount of SuperTY is the most important. Following, on the basis of the NCEP reanalysis data on different ENSO phases, the physical mechanism of the effect of ENSO on tropical cyclones of different degrees(especially the high intensity tropical cyclones), were also analyzed.It was concluded that there are some key zones in the Northwestern Pacific Ocean, where the number of the SuperTY in ENSO years is different from that in ordinary years. And ENSO events affect the genesis location and number of SuperTY mainly by changing the low-level relative vorticity and the sea surface temperature in some key zones.
2013, 35(2): 35-42.
doi: 10.3969/j.issn.0253 4193.2013.02.005
Abstract:
Based on the in situ dataset observed by two Bio-Argo floats deployed in the northwestern and eastern basins of Mediterranean Sea in 2008-2009, this study focuses on the seasonal variations of colored dissolved organic matter (CDOM) subsurface maximum. The research results show that the subsurface CDOM bloom started in summer accompanied by gradual decreasing of chlorophyll-a concentration, and disappeared in winter owing to deep mixing effect. In addition, the depth of subsurface CDOM maximum was always following the depth of deep chlorophyll-a maximum (DCM) during the CDOM bloom period, which suggests that the source of oceanic CDOM is almost certainly the result of phytoplankton degradation, although chlorophyll and CDOM are not correlated directly. It is assumed that a probable strong coupling between phytoplankton and bacteria leads to the obvious contravariance observed between CDOM and chlorophyll-a.
Based on the in situ dataset observed by two Bio-Argo floats deployed in the northwestern and eastern basins of Mediterranean Sea in 2008-2009, this study focuses on the seasonal variations of colored dissolved organic matter (CDOM) subsurface maximum. The research results show that the subsurface CDOM bloom started in summer accompanied by gradual decreasing of chlorophyll-a concentration, and disappeared in winter owing to deep mixing effect. In addition, the depth of subsurface CDOM maximum was always following the depth of deep chlorophyll-a maximum (DCM) during the CDOM bloom period, which suggests that the source of oceanic CDOM is almost certainly the result of phytoplankton degradation, although chlorophyll and CDOM are not correlated directly. It is assumed that a probable strong coupling between phytoplankton and bacteria leads to the obvious contravariance observed between CDOM and chlorophyll-a.
2013, 35(2): 43-51.
doi: 10.3969/j.issn.0253 4193.2013.02.006
Abstract:
As a new tool for ocean wave measurement interiorly, X-band radar can be used to provide sea state information and a wave field can be get form an image sequence.However, there are still some problems in the retrieval of wave frequency spectrum and significant wave height (Hs).A nonlinear regression method was used to fit the in situ wave frequency spectrum and radar one-dimension image spectrum with standard PM, JONSWAP and TMA spectrum, and the basic form and the corresponding spectral parameters can be obtained accurately.Then, a generalized regression neural network model (GRNN) was introduced to retrieve the wave frequency spectral parameters from the one-dimensional radar image spectrum parameters.In the model, the signal-to-noise ratio (SNR) of the image sequence was added to set up a nonlinear relationship with Hs,and the inversion results with the in situ data and the traditional algorithm result (the establishment of the linear regression equation between SNR and Hs) were compared.The results show that the mean error of spectral parameters and significant wave height are less than 20%, while the mean error of the traditional algorithm is more than 20%.
As a new tool for ocean wave measurement interiorly, X-band radar can be used to provide sea state information and a wave field can be get form an image sequence.However, there are still some problems in the retrieval of wave frequency spectrum and significant wave height (Hs).A nonlinear regression method was used to fit the in situ wave frequency spectrum and radar one-dimension image spectrum with standard PM, JONSWAP and TMA spectrum, and the basic form and the corresponding spectral parameters can be obtained accurately.Then, a generalized regression neural network model (GRNN) was introduced to retrieve the wave frequency spectral parameters from the one-dimensional radar image spectrum parameters.In the model, the signal-to-noise ratio (SNR) of the image sequence was added to set up a nonlinear relationship with Hs,and the inversion results with the in situ data and the traditional algorithm result (the establishment of the linear regression equation between SNR and Hs) were compared.The results show that the mean error of spectral parameters and significant wave height are less than 20%, while the mean error of the traditional algorithm is more than 20%.
2013, 35(2): 52-58.
doi: 10.3969/j.issn.0253 4193.2013.02.007
Abstract:
Ocean color remote sensing is an important technical method for marine environment monitoring. It is vital to monitor the change of the calibration coefficients of the sensors related to their status in producing precise quantitative remote sensing products for all ocean color sensors.Focusing on HY-1B satellite-borne ocean color sensor, absolute calibration over Rayleigh scattering was developed with clear ocean areas. Seven zones were selected by analyzing chlorophyll concentration, water-leaving radiance and aerosol data derived from SeaWiFS measurements. It shows that the calibration coefficients made over different areas at different time are quite consistent. The standard deviations are between 0.9% and 2.1% for all visible bands. It can be concluded that the calibration over Rayleigh scattering is an efficient method independent of in-situ measurements for the absolute calibration of optical sensors from 4 areas selected in December 2010. This method can provide calibration coefficients with 4.09% maximal error.
Ocean color remote sensing is an important technical method for marine environment monitoring. It is vital to monitor the change of the calibration coefficients of the sensors related to their status in producing precise quantitative remote sensing products for all ocean color sensors.Focusing on HY-1B satellite-borne ocean color sensor, absolute calibration over Rayleigh scattering was developed with clear ocean areas. Seven zones were selected by analyzing chlorophyll concentration, water-leaving radiance and aerosol data derived from SeaWiFS measurements. It shows that the calibration coefficients made over different areas at different time are quite consistent. The standard deviations are between 0.9% and 2.1% for all visible bands. It can be concluded that the calibration over Rayleigh scattering is an efficient method independent of in-situ measurements for the absolute calibration of optical sensors from 4 areas selected in December 2010. This method can provide calibration coefficients with 4.09% maximal error.
2013, 35(2): 59-71.
doi: 10.3969/j.issn.0253 4193.2013.02.008
Abstract:
Observations were carried out at the lower reaches of the Huanghe River to analyze dissolved and particulate nutrient elements from 2009 to 2011. The results show that the concentrations of various N forms were lower in the flood season than those in the dry season. Dissolved inorganic nitrogen (DIN) was the predominant species of TDN. Particulate phosphorus was the major form of phosphorus affected by high content of suspended particulate matter. Phosphate represented 68% of TDP. Both silicate and biogenic silicon were higher in the flood season than those in the dry season. The BSi was 20% of the sum of BSi and SiO3-Si. Particulate phosphorus and biogenic silica had a positive correlation with SPM. Nutrient composition was characterized by high N/P and Si/P ratios and low Si/N ratio. In the past decades, dissolved inorganic nitrogen concentrations increased, dissolved phosphorus concentrations remained at a stable level, and silicate concentrations slightly decreased. Nutrient transport fluxes from the river into the Bohai show significantly seasonal changes. Water discharge, sediment load and nutrient fluxes in the flood season accounted for 42%~84% of the annual loads. The concentrations and composition of nutrients had an obvious change during the water-sediment regulation event. Abundant water, sediment and nutrient were transported to the Huanghe estuary and the adjacent Bohai during the water-sediment regulation event. The concentrations of N and ratios of DIN/PO4-P decreased, while the concentrations of P and Si and the ratios of SiO3-Si/PO4-P and SiO3-Si/DIN increased, the proportion of particulate phosphorus and BSi showed a distinct rise. It is expected that high terrestrial inputs transported by the Yellow River during the water-sediment regulation will lead to an extensive impact on the ecological system of the Bohai.
Observations were carried out at the lower reaches of the Huanghe River to analyze dissolved and particulate nutrient elements from 2009 to 2011. The results show that the concentrations of various N forms were lower in the flood season than those in the dry season. Dissolved inorganic nitrogen (DIN) was the predominant species of TDN. Particulate phosphorus was the major form of phosphorus affected by high content of suspended particulate matter. Phosphate represented 68% of TDP. Both silicate and biogenic silicon were higher in the flood season than those in the dry season. The BSi was 20% of the sum of BSi and SiO3-Si. Particulate phosphorus and biogenic silica had a positive correlation with SPM. Nutrient composition was characterized by high N/P and Si/P ratios and low Si/N ratio. In the past decades, dissolved inorganic nitrogen concentrations increased, dissolved phosphorus concentrations remained at a stable level, and silicate concentrations slightly decreased. Nutrient transport fluxes from the river into the Bohai show significantly seasonal changes. Water discharge, sediment load and nutrient fluxes in the flood season accounted for 42%~84% of the annual loads. The concentrations and composition of nutrients had an obvious change during the water-sediment regulation event. Abundant water, sediment and nutrient were transported to the Huanghe estuary and the adjacent Bohai during the water-sediment regulation event. The concentrations of N and ratios of DIN/PO4-P decreased, while the concentrations of P and Si and the ratios of SiO3-Si/PO4-P and SiO3-Si/DIN increased, the proportion of particulate phosphorus and BSi showed a distinct rise. It is expected that high terrestrial inputs transported by the Yellow River during the water-sediment regulation will lead to an extensive impact on the ecological system of the Bohai.
2013, 35(2): 72-81.
doi: 10.3969/j.issn.0253 4193.2013.02.009
Abstract:
The environmental background values for Cu, Zn, As, Pb, Hg, Cd in the Beibu Gulf are measured by the investigation data obtained in 2007, and their difference from background values of the South China Sea and terrigenous soil are also studied.The trend analysis of heavy metal contents in surface sediments and core sediments in the Beibu Gulf shows that in recent 100 a,the contents of Cu, As, Hg and Cd in coastal sediments are basically increasing; the trends in the middle of the Beibu Gulf are complicated; heavy metal contents in the sediments of the mouth of the gulf are stable. According to the distribution and trends of the heavy metal contents in sediments, it is qualitatively concluded that the environmental behaviors of heavy metals in the Beibu Gulf are affected by the human activity in Guangxi coastal areas, among which Cd, Hg, As are deeply affected. The main sources of heavy metals in the Beibu Gulf are terrigenous input from Guangxi, ocean currents via Qiongzhou Strait also contributed to heavy metal inputs.
The environmental background values for Cu, Zn, As, Pb, Hg, Cd in the Beibu Gulf are measured by the investigation data obtained in 2007, and their difference from background values of the South China Sea and terrigenous soil are also studied.The trend analysis of heavy metal contents in surface sediments and core sediments in the Beibu Gulf shows that in recent 100 a,the contents of Cu, As, Hg and Cd in coastal sediments are basically increasing; the trends in the middle of the Beibu Gulf are complicated; heavy metal contents in the sediments of the mouth of the gulf are stable. According to the distribution and trends of the heavy metal contents in sediments, it is qualitatively concluded that the environmental behaviors of heavy metals in the Beibu Gulf are affected by the human activity in Guangxi coastal areas, among which Cd, Hg, As are deeply affected. The main sources of heavy metals in the Beibu Gulf are terrigenous input from Guangxi, ocean currents via Qiongzhou Strait also contributed to heavy metal inputs.
2013, 35(2): 82-89.
doi: 10.3969/j.issn.0253 4193.2013.02.010
Abstract:
Some cold-seep carbonate chimneys collected from the north continental slope of the South China Sea were studied for petrology, mineralogy and geochemistry. The cross cut samples clearly showed distinctive layers. In the inner layer, the carbonate content was higher, and contained higher MgCO3 and bigger minerals, and the minerals crystallized better. While the outer layer contained higher detritus such as Al and Si. The isotopes compositions of δ13C and δ18O were different between the inner and outer layers. For the two studied samples, in the inner layer, δ13C is -40.80×10-3 and -31.27×10-3,and δ18O is 2.67×10-3 and 2.00×10-3, individually, and in the outer layer, δ13C is -31.26×10-3 and -30.99×10-3, and δ18O is 0.48×10-3 and 1.85×10-3, individually. Integrating the former researches near this area, the pattern that δ13C was increasing and δ18O was decreasing from the inner layer to the outer layer. The δ13C and δ18O curves using 1mm interval samples range from -27.50×10-3 to -32.05×10-3 and 0.78×10-3 to 2.34×10-3 from the outer layer to the inner layer individually, which showed the layer structure well. In the outer 6 mm, the δ13C and δ18O had a strongly negative correlation, which correlation coefficient r2 was 0.996 7. According to the above results, the characteristic of CH4 fluid, its diffusing model and its influences on the sedimentary environment were discussed. The carbonate chimneys studied in this paper were supposed to form in a single channel, but which layer was older needs more dating researches. The outer 6 mm was influenced strongly by the seawater. The results can be used to recover the methane seep system of the northern continental slope of the South China Sea and can also give some relationships between cold seeps and hydrothermal seeps.
Some cold-seep carbonate chimneys collected from the north continental slope of the South China Sea were studied for petrology, mineralogy and geochemistry. The cross cut samples clearly showed distinctive layers. In the inner layer, the carbonate content was higher, and contained higher MgCO3 and bigger minerals, and the minerals crystallized better. While the outer layer contained higher detritus such as Al and Si. The isotopes compositions of δ13C and δ18O were different between the inner and outer layers. For the two studied samples, in the inner layer, δ13C is -40.80×10-3 and -31.27×10-3,and δ18O is 2.67×10-3 and 2.00×10-3, individually, and in the outer layer, δ13C is -31.26×10-3 and -30.99×10-3, and δ18O is 0.48×10-3 and 1.85×10-3, individually. Integrating the former researches near this area, the pattern that δ13C was increasing and δ18O was decreasing from the inner layer to the outer layer. The δ13C and δ18O curves using 1mm interval samples range from -27.50×10-3 to -32.05×10-3 and 0.78×10-3 to 2.34×10-3 from the outer layer to the inner layer individually, which showed the layer structure well. In the outer 6 mm, the δ13C and δ18O had a strongly negative correlation, which correlation coefficient r2 was 0.996 7. According to the above results, the characteristic of CH4 fluid, its diffusing model and its influences on the sedimentary environment were discussed. The carbonate chimneys studied in this paper were supposed to form in a single channel, but which layer was older needs more dating researches. The outer 6 mm was influenced strongly by the seawater. The results can be used to recover the methane seep system of the northern continental slope of the South China Sea and can also give some relationships between cold seeps and hydrothermal seeps.
2013, 35(2): 90-112.
doi: 10.3969/j.issn.0253 4193.2013.02.011
Abstract:
Conical and flat-topped seamounts are two kinds of seamounts in the ocean, also the main basis on which cobalt-rich crusts grow, with obvious differences in topography, at the same time in the resources status and distribution of the crusts. Based on the classification of studying seamounts, systematic contrast in mineralization characteristics, macrostructure and microstructure, mineral and chemical composition, and space distribution law of crusts of two kinds of seamounts from the central Pacific seamounts are given. The results show that small volume and continuous slope topography raise the oxidizing degree of environment and strengthen the bottom flow intensity of conical seamounts, lead to a larger crusts thickness, more mineral-forming and biogenic elements, so they develop a long continuous mineralized belt. Flat-topped seamounts have a big volume, their top and the cliff of slope make against to growth of cobalt-rich crusts,an area with strong bottom only distributes in the marginal zone of seamounts top and ridge on the slope,the oxidizing degree is low as a whole, they also have relatively frequent tectonic movements, all these bring forth their thinner crusts thickness,Fe, clastic and hydrothermal material contents are higher and perspective mineralized area is narrower than conical seamounts.
Conical and flat-topped seamounts are two kinds of seamounts in the ocean, also the main basis on which cobalt-rich crusts grow, with obvious differences in topography, at the same time in the resources status and distribution of the crusts. Based on the classification of studying seamounts, systematic contrast in mineralization characteristics, macrostructure and microstructure, mineral and chemical composition, and space distribution law of crusts of two kinds of seamounts from the central Pacific seamounts are given. The results show that small volume and continuous slope topography raise the oxidizing degree of environment and strengthen the bottom flow intensity of conical seamounts, lead to a larger crusts thickness, more mineral-forming and biogenic elements, so they develop a long continuous mineralized belt. Flat-topped seamounts have a big volume, their top and the cliff of slope make against to growth of cobalt-rich crusts,an area with strong bottom only distributes in the marginal zone of seamounts top and ridge on the slope,the oxidizing degree is low as a whole, they also have relatively frequent tectonic movements, all these bring forth their thinner crusts thickness,Fe, clastic and hydrothermal material contents are higher and perspective mineralized area is narrower than conical seamounts.
2013, 35(2): 113-125.
doi: 10.3969/j.issn.0253 4193.2013.02.012
Abstract:
On the basis of trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese Arctic Research Expedition, the fish biodiversity feature, such as fish species composition, dominant species, biodiversity and faunal characteristics were conducted. We discussed the responses of fishes due to the quick changes of Arctic climate. The results show that a total of 41 species in 14 families have been recorded in Bering Sea and Chukchi Sea. The dominant species are Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber. There are 35 cold water species and 6 cold temperate species. The habitat types of fish can be grouped as follows: 35 demersal fishes, 5 benthopelagic fishes, and 1 pelagic fish, respectively. Shannon-Wiener diversity index(H')(range between 0 and 2.18, and 1.21 in average) was not high, descend from south to north. Climate change has urged some fishes to shift in their latitudinal and longitudinal distribution around the Arctic and Subarctic areas, this could lead to the declination of Arctic fisheries resources.
On the basis of trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese Arctic Research Expedition, the fish biodiversity feature, such as fish species composition, dominant species, biodiversity and faunal characteristics were conducted. We discussed the responses of fishes due to the quick changes of Arctic climate. The results show that a total of 41 species in 14 families have been recorded in Bering Sea and Chukchi Sea. The dominant species are Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber. There are 35 cold water species and 6 cold temperate species. The habitat types of fish can be grouped as follows: 35 demersal fishes, 5 benthopelagic fishes, and 1 pelagic fish, respectively. Shannon-Wiener diversity index(H')(range between 0 and 2.18, and 1.21 in average) was not high, descend from south to north. Climate change has urged some fishes to shift in their latitudinal and longitudinal distribution around the Arctic and Subarctic areas, this could lead to the declination of Arctic fisheries resources.
2013, 35(2): 126-132.
doi: 10.3969/j.issn.0253 4193.2013.02.013
Abstract:
Based on literature and survey data of fish composition collected by bottom trawl investigation from 2006 to 2007 in Xiamen coastal waters,the fish fauna was set up, fish community and the taxonomic diversity and distinctness by using taxonomic diversity Δ+ and taxonomic distinctness Λ+ were analyzed. The results show that: there were 649 species of fishes recorded in Xiamen coastal waters. 331 species of fishes were available at present,belonging to 2 classes, 22 orders, 90 families and 181 genera, as for the Chondrichthyes fishes were composed of 5 orders, 9 families, 9 genera and 15 species, while the Actinopterygii fishes were composed of 17 orders, 81 families, 172 genera and 316 species. The taxonomic diversity Δ+ and taxonomic distinctness Λ+ of the fish community master list in Xiamen coastal waters were 79.267 and 220.96, 77.504 and 245.34 at present, respectively. The taxonomic diversity Δ+ in winter and spring was higher than summer and autumn, and it was lowest in summer. While the taxonomic distinctness Λ+ was highest in summer and lower in winter and spring. The fish compositions in autumn and winter had the highest similarity, followed by summer, and lowest in spring. Compared with historical data, fish community in Xiamen coastal waters is being smaller in the taxonomic range and narrower in ecological amplitude. The stability of the fish community is potential recession and the ability to resist change is down.
Based on literature and survey data of fish composition collected by bottom trawl investigation from 2006 to 2007 in Xiamen coastal waters,the fish fauna was set up, fish community and the taxonomic diversity and distinctness by using taxonomic diversity Δ+ and taxonomic distinctness Λ+ were analyzed. The results show that: there were 649 species of fishes recorded in Xiamen coastal waters. 331 species of fishes were available at present,belonging to 2 classes, 22 orders, 90 families and 181 genera, as for the Chondrichthyes fishes were composed of 5 orders, 9 families, 9 genera and 15 species, while the Actinopterygii fishes were composed of 17 orders, 81 families, 172 genera and 316 species. The taxonomic diversity Δ+ and taxonomic distinctness Λ+ of the fish community master list in Xiamen coastal waters were 79.267 and 220.96, 77.504 and 245.34 at present, respectively. The taxonomic diversity Δ+ in winter and spring was higher than summer and autumn, and it was lowest in summer. While the taxonomic distinctness Λ+ was highest in summer and lower in winter and spring. The fish compositions in autumn and winter had the highest similarity, followed by summer, and lowest in spring. Compared with historical data, fish community in Xiamen coastal waters is being smaller in the taxonomic range and narrower in ecological amplitude. The stability of the fish community is potential recession and the ability to resist change is down.
2013, 35(2): 133-142.
doi: 10.3969/j.issn.0253 4193.2013.02.014
Abstract:
The genetic gain and economic benefit from a multi-trait breeding scheme with Chinese shrimp (Fenneropenaeus chinensis) were calculated after performing 20 selections. The breeding object was made up of harvest body weight (BW), survival rate (SR) and feed intake (FI), but the trait FI was not included in the selection index. Selection response and genetic gain of the breeding object were estimated based on selection index theory. Economic benefit was predicted after nucleus shrimp was multiplied by a pyramid breeding structure (nucleus, multiplication and production populations). The sensitivity of profit (RP) and benefit/cost ratio (BCR) to a number of factors were examined. It comprises biological parameters (heritability value, accounting for feed intake), economic parameters (price of shrimp, price of feed, discount rate, initial investment, annual cost), and operational parameters (the year when first return occurs, multiplication efficiency). For the base situation, selection responses on BW, SR and FI were 0.81 g,1.41% and 1.30 g, respectively; their economic values were CNY 32, CNY 20 and CNY-8, respectively; the overall gain in economic units for the breeding object was CNY 43.69; the RP and BCR of this program were CNY 8 660.99 and 14.34 after preforming 20 selections. Heritability values had a moderate effect for RP and BCR. Greater heritabilities resulted in greater RP and BCR. The RP and BCR were greater than those of base situation when the economic value of FI was set as 0. RP and BCR were sensitive to the change of the shrimp price. The changes from the feed price, discounted rate and annual cost had a relatively small effect on RP and BCR. Initial investment also had a small effect on RP, but had a great effect on BCR. Delays in obtaining the first return in this program resulted in reduced EB and BCR. However, the greatest contribution to variations in RP and BCR came from the improvements in the multiplication efficiency at the level of both the nucleus and the hatcheries. High multiplication efficiency could be achieved by use of the high fecundity and the pyramid industry structure in Chinese shrimp. RP and BCR were increased by 1 866.92% and 1 736.75% when the production population was multiplied by 1 736.15%.
The genetic gain and economic benefit from a multi-trait breeding scheme with Chinese shrimp (Fenneropenaeus chinensis) were calculated after performing 20 selections. The breeding object was made up of harvest body weight (BW), survival rate (SR) and feed intake (FI), but the trait FI was not included in the selection index. Selection response and genetic gain of the breeding object were estimated based on selection index theory. Economic benefit was predicted after nucleus shrimp was multiplied by a pyramid breeding structure (nucleus, multiplication and production populations). The sensitivity of profit (RP) and benefit/cost ratio (BCR) to a number of factors were examined. It comprises biological parameters (heritability value, accounting for feed intake), economic parameters (price of shrimp, price of feed, discount rate, initial investment, annual cost), and operational parameters (the year when first return occurs, multiplication efficiency). For the base situation, selection responses on BW, SR and FI were 0.81 g,1.41% and 1.30 g, respectively; their economic values were CNY 32, CNY 20 and CNY-8, respectively; the overall gain in economic units for the breeding object was CNY 43.69; the RP and BCR of this program were CNY 8 660.99 and 14.34 after preforming 20 selections. Heritability values had a moderate effect for RP and BCR. Greater heritabilities resulted in greater RP and BCR. The RP and BCR were greater than those of base situation when the economic value of FI was set as 0. RP and BCR were sensitive to the change of the shrimp price. The changes from the feed price, discounted rate and annual cost had a relatively small effect on RP and BCR. Initial investment also had a small effect on RP, but had a great effect on BCR. Delays in obtaining the first return in this program resulted in reduced EB and BCR. However, the greatest contribution to variations in RP and BCR came from the improvements in the multiplication efficiency at the level of both the nucleus and the hatcheries. High multiplication efficiency could be achieved by use of the high fecundity and the pyramid industry structure in Chinese shrimp. RP and BCR were increased by 1 866.92% and 1 736.75% when the production population was multiplied by 1 736.15%.
2013, 35(2): 143-153.
doi: 10.3969/j.issn.0253 4193.2013.02.015
Abstract:
Calanus sinicus is a planktonic copepod with wide geographical distribution on the continental shelf of the northwest Pacific.It plays an important role in marine system.Four cruises were conducted from July 2006 to October 2007 in order to understand the seasonal and horizontal variations with the influences of monsoon, ocean current and temperature on its distributions on the northwest continental shelf of the South China Sea.The diel vertical migration (DVM) of C.sinicus was studied at one station located in the southeast of Hainan Island during summer.The results showed that the distribution of C.sinicus abundance varied seasonally and regionally.The mean of C.sinicus abundance was high with 23.30±77.78 ind./m3 in spring, and decreased to 13.74±45.10 ind./m3 in summer.It disappeared in autumn and did not enter into the study area during the investigated period in winter.The surveyed area was divided into three sub-regions in order to further analyze the regional difference, including the east inshore waters of Leizhou Peninsula, the east inshore waters of Hainan Island and and the offshore waters from Leizhou Peninsula to Hainan Island.The average abundance of C.sinicus within the inshore waters of Leizhou Peninsula was reached to be 115.63 (±145.93) and 68.12 (±84.00) ind/m3 in spring and summer, respectively, which was higher than those of the inshore Hainan Island and the offshore from Leizhou Peninsula to Hainan Island.The behavior of C.sinicus DVM was not found in the upwelling area in summer. C.sinicus seemed to be mostly habited in the bottom layer in order to avoid the damage of high temperature in the surface layer.The study area is the seasonal distribution zone of C.sinicus.Our findings suggested that C.sinicus was transported from the East China Sea to the northwest continental shelf of South China Sea by the Guangdong Coastal Current, which was driven by the northeast monsoon in winter and spring.The presence of a cold eddy, in addition to coastal upwelling driven by the southwest monsoon, provided suitable survival conditions for C.sinicus in summer.This species disappeared in autumn due to high temperatures (>27℃) and did not begin to enter into the northwest continental shelf of South China Sea from the East China Sea during the period of investigation in winter.C.sinicus could be considered as an indicator species for China Coastal Current driven by the northeasterly monsoon, and coastal upwelling by the southwesterly monsoon in the northern South China Sea.
Calanus sinicus is a planktonic copepod with wide geographical distribution on the continental shelf of the northwest Pacific.It plays an important role in marine system.Four cruises were conducted from July 2006 to October 2007 in order to understand the seasonal and horizontal variations with the influences of monsoon, ocean current and temperature on its distributions on the northwest continental shelf of the South China Sea.The diel vertical migration (DVM) of C.sinicus was studied at one station located in the southeast of Hainan Island during summer.The results showed that the distribution of C.sinicus abundance varied seasonally and regionally.The mean of C.sinicus abundance was high with 23.30±77.78 ind./m3 in spring, and decreased to 13.74±45.10 ind./m3 in summer.It disappeared in autumn and did not enter into the study area during the investigated period in winter.The surveyed area was divided into three sub-regions in order to further analyze the regional difference, including the east inshore waters of Leizhou Peninsula, the east inshore waters of Hainan Island and and the offshore waters from Leizhou Peninsula to Hainan Island.The average abundance of C.sinicus within the inshore waters of Leizhou Peninsula was reached to be 115.63 (±145.93) and 68.12 (±84.00) ind/m3 in spring and summer, respectively, which was higher than those of the inshore Hainan Island and the offshore from Leizhou Peninsula to Hainan Island.The behavior of C.sinicus DVM was not found in the upwelling area in summer. C.sinicus seemed to be mostly habited in the bottom layer in order to avoid the damage of high temperature in the surface layer.The study area is the seasonal distribution zone of C.sinicus.Our findings suggested that C.sinicus was transported from the East China Sea to the northwest continental shelf of South China Sea by the Guangdong Coastal Current, which was driven by the northeast monsoon in winter and spring.The presence of a cold eddy, in addition to coastal upwelling driven by the southwest monsoon, provided suitable survival conditions for C.sinicus in summer.This species disappeared in autumn due to high temperatures (>27℃) and did not begin to enter into the northwest continental shelf of South China Sea from the East China Sea during the period of investigation in winter.C.sinicus could be considered as an indicator species for China Coastal Current driven by the northeasterly monsoon, and coastal upwelling by the southwesterly monsoon in the northern South China Sea.
2013, 35(2): 154-160.
doi: 10.3969/j.issn.0253 4193.2013.02.016
Abstract:
Diatom frustules, dinoflagellate cysts, lipids and biogenic silica (BSi) have been widely used to reconstruct and indicate the marine paleo-environmental changes. In this study, five biological and chemical proxies including fossil diatoms, dinoflagellage cysts, brassicasterol, dinosterol and biogenic silica, were analyzed in the surface sediment of the Sishili Bay for the comparison of their ecological roles. Based on the results of correlation analysis and indicative capability of the five proxies, a multi-proxy approach was suggested. Diatom frustules showed obviously positive correlation with the brassicasterol and BSi values, respectively (P<0.05); the brassicasterol and BSi value performed well in the corrections and improvement for the accuracy of indication from fossil diatom. However, no significant correlations were found between dinoflagellate cysts and dinosterol values; and in a comparison, dinosteral displayed a better capability to indicate the biomass of dinoflagellate than cysts. A combination of using biological and chemical parameters can not only improve the accuracy of biomass indication but also provide the species composition for a better understanding of how algae response to changed environment.
Diatom frustules, dinoflagellate cysts, lipids and biogenic silica (BSi) have been widely used to reconstruct and indicate the marine paleo-environmental changes. In this study, five biological and chemical proxies including fossil diatoms, dinoflagellage cysts, brassicasterol, dinosterol and biogenic silica, were analyzed in the surface sediment of the Sishili Bay for the comparison of their ecological roles. Based on the results of correlation analysis and indicative capability of the five proxies, a multi-proxy approach was suggested. Diatom frustules showed obviously positive correlation with the brassicasterol and BSi values, respectively (P<0.05); the brassicasterol and BSi value performed well in the corrections and improvement for the accuracy of indication from fossil diatom. However, no significant correlations were found between dinoflagellate cysts and dinosterol values; and in a comparison, dinosteral displayed a better capability to indicate the biomass of dinoflagellate than cysts. A combination of using biological and chemical parameters can not only improve the accuracy of biomass indication but also provide the species composition for a better understanding of how algae response to changed environment.
2013, 35(2): 161-167.
doi: 10.3969/j.issn.0253 4193.2013.02.017
Abstract:
The temporal and spatial variations of the net sediment flux overtopping the South Leading Jetty in the North Passage of the Changjiang Estuary are studied based on the field measured data.The results show that: (1) timely varying unit width net overtopping sediment flux has a good linear relationship at each field measuring stations along the South Leading Jetty; (2) sections of S4 to S7 jetty and S2 to S3 jetty are the leading sediment overtopping channel with extreamly high sediment transportation rate;and(3) Annual averaged net sediment flux overtopping the South Leading Jetty is about 296.6Mt, 62.24% of which happens in the flood season and 37.76% does in the dry season.
The temporal and spatial variations of the net sediment flux overtopping the South Leading Jetty in the North Passage of the Changjiang Estuary are studied based on the field measured data.The results show that: (1) timely varying unit width net overtopping sediment flux has a good linear relationship at each field measuring stations along the South Leading Jetty; (2) sections of S4 to S7 jetty and S2 to S3 jetty are the leading sediment overtopping channel with extreamly high sediment transportation rate;and(3) Annual averaged net sediment flux overtopping the South Leading Jetty is about 296.6Mt, 62.24% of which happens in the flood season and 37.76% does in the dry season.
2013, 35(2): 168-177.
doi: 10.3969/j.issn.0253 4193.2013.02.018
Abstract:
The presence of speckle noise in the marine spill oil SAR images seriously affects the follow-up image segmentation, feature extraction and classification. To suppress the speckle in the marine spill oil SAR images more effectively, a method of reducing the speckle noise in the marine spill oil SAR images based on the hidden Markov tree model in complex Contourlet transform domain is proposed in this paper.firstly, the observed image is taken the logarithm and the complex contourlet transform is performed. Then the hidden Markov tree model is adopted to a model the band pass directional subband coefficients between adjacent scales in complex contourlet domain. Moreover, the denoised coefficients are estimated according to Bayes minimum mean square error criterion. Finally, the inverse complex contourlet transform and the exponential transform are performed to obtain the despeckled image. A large number of experimental results show that, compared with four classical filtering methods such as Lee filter, Kuan filter, Frost filter and Gamma Map filter, and the methods based on the hidden Markov tree model in wavelet or contourlet transform domain, the proposed method in this paper has superior comprehensive performance according to subjective visual and objective quantitative evaluation. It is an effective preprocessing method of marine spill oil detection based on SAR remote sensing images.
The presence of speckle noise in the marine spill oil SAR images seriously affects the follow-up image segmentation, feature extraction and classification. To suppress the speckle in the marine spill oil SAR images more effectively, a method of reducing the speckle noise in the marine spill oil SAR images based on the hidden Markov tree model in complex Contourlet transform domain is proposed in this paper.firstly, the observed image is taken the logarithm and the complex contourlet transform is performed. Then the hidden Markov tree model is adopted to a model the band pass directional subband coefficients between adjacent scales in complex contourlet domain. Moreover, the denoised coefficients are estimated according to Bayes minimum mean square error criterion. Finally, the inverse complex contourlet transform and the exponential transform are performed to obtain the despeckled image. A large number of experimental results show that, compared with four classical filtering methods such as Lee filter, Kuan filter, Frost filter and Gamma Map filter, and the methods based on the hidden Markov tree model in wavelet or contourlet transform domain, the proposed method in this paper has superior comprehensive performance according to subjective visual and objective quantitative evaluation. It is an effective preprocessing method of marine spill oil detection based on SAR remote sensing images.
2013, 35(2): 178-186.
doi: 10.3969/j.issn.0253 4193.2013.02.019
Abstract:
On the basis of the data of four seasons of seawater and sediments from the 908 survey in the Pearl River Estuary, the concentration distribution characteristics of the heavy metals in seawater and sediments were made; results show that the mean content of seven heavy metals (Cu,Pb,Zn,Cd,Cr,Hg,As) in Pearl River Estuary and surrounding seas all belonged to the Ⅰ-level seawater quality standard, and the correlation between the heavy metals and environmental factors is obtained through mathematic statistic method. The result indicates that in the estuarine the heavy metals' main process is diluting and mixing,the heavy metals in SPM mainly desorb under acidification effect, and oxidation-reduction has little influence.There was a statistically significant correlation between the element Cu-Zn,Pb-Zn,Cu-Cd,Pb-Cd,Zn-Cd,Pb-Cr,Zn-Cr,and Cd-Cr in sediments,which indicates that they have similar geochemical properties and sources. The method of potential ecological risk index presented by Lars Hakanson was used to assess the heavy metals' ecological risk.The main source of the potential ecological risk of the sediment are Cd,Hg, which is worth the key attention that the pollution levels and the potential ecological risks of Cd local surged in sediments.
On the basis of the data of four seasons of seawater and sediments from the 908 survey in the Pearl River Estuary, the concentration distribution characteristics of the heavy metals in seawater and sediments were made; results show that the mean content of seven heavy metals (Cu,Pb,Zn,Cd,Cr,Hg,As) in Pearl River Estuary and surrounding seas all belonged to the Ⅰ-level seawater quality standard, and the correlation between the heavy metals and environmental factors is obtained through mathematic statistic method. The result indicates that in the estuarine the heavy metals' main process is diluting and mixing,the heavy metals in SPM mainly desorb under acidification effect, and oxidation-reduction has little influence.There was a statistically significant correlation between the element Cu-Zn,Pb-Zn,Cu-Cd,Pb-Cd,Zn-Cd,Pb-Cr,Zn-Cr,and Cd-Cr in sediments,which indicates that they have similar geochemical properties and sources. The method of potential ecological risk index presented by Lars Hakanson was used to assess the heavy metals' ecological risk.The main source of the potential ecological risk of the sediment are Cd,Hg, which is worth the key attention that the pollution levels and the potential ecological risks of Cd local surged in sediments.
2013, 35(2): 187-192.
doi: 10.3969/j.issn.0253 4193.2013.02.020
Abstract:
The meiofauna was investigated in mangrove of Dongzhai Bay, Hainan in February 2012. The results showed the main meiofauna group were Nematoda, Copepoda, Turbellaria, Polychaeta, Oligocheata, Halacaroidea and a few unidentified meiofauna in the investigated area. Free living nematode was the most dominant group, and accounted for 95.30%,97.02%,96.45%,90.53% of the meiofauna abundance in each stations. The meiofauna abundance in mangrove of Dongzhai Bay was (1 082.23±563.76)ind/(10 cm2), and the biomass was (764.06±511.63)μg/(10 cm2).The Shannon-wiener diversity index(H')was 0.26, 0.17, 0.20, 0.45, and Pielous species uniform(J)was 0.13, 0.09, 0.10, 0.23, respectively. Least significant range method (LSR) for multiple comparisons analysis showed that meiofauna in each stations was significant difference. Mangrove of Dongzhai Bay could be polluted by organic matter according to ratio value of Nematoda and Copepoda.
The meiofauna was investigated in mangrove of Dongzhai Bay, Hainan in February 2012. The results showed the main meiofauna group were Nematoda, Copepoda, Turbellaria, Polychaeta, Oligocheata, Halacaroidea and a few unidentified meiofauna in the investigated area. Free living nematode was the most dominant group, and accounted for 95.30%,97.02%,96.45%,90.53% of the meiofauna abundance in each stations. The meiofauna abundance in mangrove of Dongzhai Bay was (1 082.23±563.76)ind/(10 cm2), and the biomass was (764.06±511.63)μg/(10 cm2).The Shannon-wiener diversity index(H')was 0.26, 0.17, 0.20, 0.45, and Pielous species uniform(J)was 0.13, 0.09, 0.10, 0.23, respectively. Least significant range method (LSR) for multiple comparisons analysis showed that meiofauna in each stations was significant difference. Mangrove of Dongzhai Bay could be polluted by organic matter according to ratio value of Nematoda and Copepoda.
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