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1.
In order to approach the characteristics of nitrogen and phosphorus pollution caused by cage culture and the balance of nitrogen and phosphorus during the process of cage culture, a monitoring was conducted in Daya Bay of Guangdong Province, China from April 2002 to Jane 2003. The results show that the concentrations of total nitrogen (TN) in the waters at the sites with five and ten years of cage culture history are 1.8 and 2.3 times of that at control site respectively. Ammonium (NH3-N) is the main form of nitrogen in spring while nitrate ( NO3 -) in winter. The concentrations of TN, total dissolved nitrogen (TDN) and dissolved organic nitrogen (DON) are highest in autumn. The concentration of phosphorus increases with the increasing of the culturing time, among which phosphate ( PO 34-) increases most obviously. The concentrations of total phosphorus (TP) and total dissolved phosphorus (TDP) are highest in autumn. The nitrogen and phosphorus are accumulated significantly in the sediment of cage culture area. The model of N balance in the cage culture area: bait (70.62%) fry (0.28%) input by tide (14.8%) release from sediment (14.3%) = harvest of adult fish (12.07%) deposition into sediment (28.75%) output by tide (56.18%) others (3.00%). The model of P balance: bait (83.11%) fry (0.17%) input by tide (12.23%) release from sediment (4.49%) = harvest of adult fish (8.43%) deposition into sediment (48.59%) output by tide (41.94%) others (1.04%). In one fish growth year, the contents of nitrogen and phosphorus in harvest of adult fish are only 17.0% and 10.1% of the contents of nitrogen and phosphorus in fish bait and fry, wherein 83% of nitrogen and more than 89% of phosphorus in fish bait became marine pollutants.  相似文献   

2.
SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN   总被引:1,自引:0,他引:1  
A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confrrmed by elemental analysis and FI‘-IR spectra analysis. The adsorption properties of sulthydryl chitosan for Cu(Ⅱ ), Cd(Ⅱ ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ) and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.  相似文献   

3.
Silva  J. Paulo  Alves  Celso  Pinteus  Susete  Silva  Joana  Valado  Ana  Pedrosa  Rui  Pereira  Leonel 《中国海洋湖沼学报》2019,37(3):825-835
Osmundea pinnatifida is a red edible seaweed known as pepper dulse. O. pinnatifida was cultivated in the farm of ALGAplus(Ilhavo, Portugal). This farm is integrated with a seabream and seabass commercial aquaculture and uses the nutrient-enriched water resultant from the fish production as its cultivation medium in the integrated multi-trophic aquaculture(IMTA) manner. Wild and IMTA-cultivated samples of O. pinnatifida were screened for antioxidant and antitumor activities. The antioxidant capacity of solvent extracts from wild and IMTA cultivated samples was assessed in two methods(2,2-diphenyl-1-picrylhydrazyl(DPPH) and oxygen radical absorbance capacity(ORAC)), and their total phenolic contents(TPC) were estimated. Antitumor activity was evaluated in three different tumor cell lines(HepG-2, MCF-7, and SH-SY5Y) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay. Among the solvents used for extraction, dichloromethane was the most effective to extract phenolic compounds and presented higher ORAC. A significant correlation was found between TPC and ORAC,which was also sustained by the principal components analysis(PCA). Dichloromethane extracts induced a cytostatic effect on MCF-7 cells and showed weak cytotoxicity to SH-SY5Y cells and weak impact on cell proliferation. Overall, there were no statistically significant differences in the biological activities shown by the wild and IMTA-cultivated samples. Hence, O. pinnatifida can be obtained in an economical and environmentally sustainable way through IMTA, maintaining bioactive properties in a high potential for further nutraceutical purposes.  相似文献   

4.
In this study,families of selected population for growth(SP_BWT),selected population for white spot syndrome virus(WSSV)resistance(SP_RW),Bohai wild population(WP_BH)and Huanghai wild population(WP_HH)of F.chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing.Growth and survival performance were studied among four populations after a 70 days common test.The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH.Compared with WP_BH,body weight of SP_BWT increased by 23.41%(P0.01)and that of SP_RW by 12.20%(P0.05).Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH,which increased by 34.31%(P0.01)and 22.10%(P0.05),respectively.The mean AGR of four populations was 0.19,0.18,0.17 and 0.16 g d~(-1),respectively.Coefficient of variation of body weight among four populations was high,which ranged from 32.67% to 35.25%.Such a range showed that there was the potentiality for further improvement in selected populations.Coefficient of variation of survival rate among four populations was low,varying between 3.20% and 5.90%.The difference of survival was highly significant(P0.01)between SP_BWT and WP_BH,and significant(P0.05)between SP_RW and WP_BH.However,no significant difference among other populations(P0.05)was observed.Different growth performances were also observed among different families in each population.The body weight of 798F family was the highest.The absolute growth rate(AGR)was 0.25 g d~(-1),150%higher than that of the lowest one,0.1 g d~(-1) in 807F family.Survival rate of families among four populations was different.The highest was 94.74%,and the lowest was 71.88%.  相似文献   

5.
Concentrations of Cr, Co, Ni, Cu, Ga, Ge, As, Sb, W, Re, Ir, Pt and Au of two ungrouped iron meteorites, Grove Mountains (GRV) 98003 from Antarctica and Ujimqin, were measured using instrumental neutron activation analysis. According to the bulk chemistry, GRV 98003 is classified as a member of ⅠAB group, and Ujimqin as a unique one of ⅠAB iron meteorite complex. The elemental abundance pattern and correlation between elements (e. g. Ni-Au, Co-Au, As-Au, W- Au, Cu-Au, Sb-Au) of GRV 98003 are similar with those of NAW 468 (ⅠAB), but significantly depleted in refractory siderophile elements ( Re, It) and moderate volatile elements (Ca, Ge) relative to the latter. In addition, we reclassify Nantan (ⅢCD) as a member of ⅠAB main group (MG) and Yongning (ⅠA) as a unique iron meteorite related with IAB iron meteorite complex.  相似文献   

6.
Two typical satellite sea surface temperature (SST) datasets, from the Multi-functional Transport Satellite (MTSAT) and Tropical Rainfall Measuring Mission Microwave Imager (TMI), were evaluated for the East China Sea, Yellow Sea, and Bohai Sea throughout 2008. Most monthly-mean availabilities of MTSAT are higher than those of TMI, whereas the seasonal variation of the latter is less than that of the former. The analysis on the one-year data shows that the annual mean availability of MTSAT (61%) is greater than that of TMI (56%). This is mainly because MTSAT is a geostationary satellite, which achieves longer observation than the sun-synchronous TMI. The daily availability of TMI (28%-75%) is more constant than that of MTSAT (9%-93%). The signal of infrared sensors on MTSAT is easily disturbed on cloudy days. In contrast, the TMI microwave sensor can obtain information through clouds. Based on in-situ SSTs, the SST accuracy of TMI is superior to that of MTSAT. In 2008, the root mean square (RMS) error of TMI and MTSAT were 0.77 K and 0.84 K, respectively. The annual mean biases were 0.14 K (TMI) and -0.31 K (MTSAT). To attain a high availability of SSTs, we propose a fusion method to merge both SSTs. The annual mean availability of fusion SSTs increases 17% compared to MTSAT. In addition, the availabilities of the fusion SSTs become more constant. The annual mean RMS and bias of fusion SSTs (0.78 K and -0.06 K, respectively) are better than those of MTSAT (0.84 K and -0.31 K).  相似文献   

7.
The serum thyroid hormone and plasma catecholamine were examined in 18 male and 2 female members of the Chinese Antarctic Expedition (who spent the 2000 or 2001 austral winter at the Great Wall Station) . The changes of serum thyroid hormone i. e. total thyroxine (TT4) and free T4 (FT4) , total triodothyronine (TT3) and freeT3 ( FT3 ) , thyroid stimulating hormone ( TSH ) and plasma catecholamine, including norepinephrine (NE) , epinephrine ( E) and dopamine ( DA ) , were investigated by Chemoluminescence Immunoassay (CLIA) and High Performance Liquid Chromatography with electrochemical detection (HPLC-ECD) . Samples were taken at different time; (1)1 day before departure to Antarctica (16th expedition 1999/12/ 09; 17th expedition 2000/12/06). (2) 1 day after returned to China after living 54 weeks in Antarctica ( 16th expedition 2000/12/25 ; 17th expedition 2001/12/25 ). Comparing the data of before departure and returned, results showed that there was a significant decrease in the contents of TT4 (P <  相似文献   

8.
The distribution and chemical properties of colored dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea during December 2011-January 2012 were investigated. The input of freshwater and biological activities had an evident influence on the CDOM levels(characterized by the light absorption coefficient at the wavelength of 355 nm a_(355)) in the study area. The spatial distribution of CDOM levels displayed a gradually decreasing trend from the coastal waters(0.37 m~(-1)) to the open sea(0.18 m~(-1)). The spectral slope ratio(the slope ratio S_R defined as S_(275-295):S_(350-400)) during the cruise was correlated with salinity, and exhibited a large variation from inshore(average of 2.515) to offshore sites(average of 5.327) compared with the distribution of a_(355). The values of S_R were related to CDOM molecular weight(MW). The a_(355), S_R, and chlorophyll a in 37 samples collected from the surface microlayer were significantly correlated with those in the corresponding subsurface water samples, implying a strong exchange action between the microlayer and bulk water. The a_(355) and S_R of CDOM exhibited significant microlayer enrichment, with mean enrichment factors(EFs) of 1.72 and 1.62, respectively.  相似文献   

9.
Journal of Oceanology and Limnology - The Yellow Sea (YS) and East China Sea (ECS) are important marginal seas of the western Pacific. Understanding the dynamics of methane (CH4) in the YS and ECS...  相似文献   

10.
Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.  相似文献   

11.
Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements.Proximate composition,amino acid and fatty acid profiles,and toxic elements contents of farmed and wild Chanodichthys mongolicus were established and compared.Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed(P0.05).The percentages of total amino acids(TAA),total essential amino acids(TEAA),total non-essential amino acids(TNEAA)and total delicious amino acids(TDAA) in farmed fish were all significantly higher than those in the wild equivalent(PO.05).Compared to the FAO/WHO recommended reference values,the ratios of TEAA/TAA(39.84%-40.33%) were comparable to 40%and TEAA/TNEAA(66.22%-67.60%) were above 60%.Fatty acid profiles in both fanned and wild C.mongolicus were dominated by monounsaturated fatty acid(MUFA),with farmed fish contained much more MUFA content compared to wild counterpart(P0.05).Notably,wild fish exhibited significantly higher levels of total polyunsaturated fatty acid(PUFA) including eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) than farmed fish(P0.05).The EPA(C_(20:5n3))and linoleic acid(C_(18:2n6)) were the predominant PUFA in wild and fanned C.mongolicus,respectively.Moreover,farmed fish displayed an overall lower toxic element levels(As,Cd,Pb and Hg) in comparison with wild fish,and both were far lower than the established limit standard.In conclusion,our results suggest that the nutritional quality of farmed C.mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition,and therefore further studies should focus on the improving C.mongolicus diet in order to enhance the overall nutritional composition.  相似文献   

12.
The response of the North Pacific Subtropical Mode Water and Subtropical Countercurrent (STCC) to changes in greenhouse gas (GHG) and aerosol is investigated based on the 20th-century historical and single-forcing simulations with the Geophysical Fluid Dynamics Laboratory Climate Model version 3 (GFDL CM3). The aerosol effect causes sea surface temperature (SST) to decrease in the mid-latitude North Pacific, especially in the Kuroshio Extension region, during the past five decades (1950–2005), and this cooling effect exceeds the warming effect by the GHG increase. The STCC response to the GHG and aerosol forcing are opposite. In the GHG (aerosol) forcing run, the STCC decelerates (accelerates) due to the decreased (increased) mode waters in the North Pacific, resulting from a weaker (stronger) front in the mixed layer depth and decreased (increased) subduction in the mode water formation region. The aerosol effect on the SST, mode waters and STCC more than offsets the GHG effect. The response of SST in a zonal band around 40°N and the STCC to the combined forcing in the historical simulation is similar to the response to the aerosol forcing.  相似文献   

13.
THEINVESTMENTCIRCUMSTANCESANDITSCLASSIFICATIONAPPRAISALOFCHANGJIANGRIVERDELTAXuGang(许刚)SheZhixiang(佘之祥)NanjingInstituteofGeog...  相似文献   

14.
The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.  相似文献   

15.
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron eleetrovalencies (Fe2+-EDTA and Fe3+-EDTA) and species (Fe-EDTA, Fe(OH)32x and FeC6H5O7) addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe3+-EDTA, Fe2+-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content (30.70 mg/g biomass cell)was obtained under conditions of 18 μmol/L Fe2+-EDTA, despite the lower cell density (2.3x105 cell/ml)in such condition. Fe3+-EDTA is more effective than Fe2+-EDTA in improving the cell growth. Especially,the maximal steady-state cell density, 2.9x105 cell/ml was obtained at 18 μmol/L Fe3+-EDTA addition. On the other hand, all the various species of iron (EDTA-Fe, Fe(OH)32x, FeC6H5O7) are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration (36 μmol/L) of FEC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe(OH)32x/x and EDTA-Fe.  相似文献   

16.
The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70–20...  相似文献   

17.
This paper explains the meaning of investment circumstance, and analyses the overall feature of investment circumstances of the Changjiang River Delta zone and clears about its targets’ system. Then the authors use “polytarget comprehensive value evaluation rule” to make comprehensive classification appraisal of the investment circumstance of the five regions including Shanghai, Ning (Nanjing)-Zhen (Zhenjiang)-Yang(Yangzhou), Su(Suzhou)-Xi(Wuxi)-Chang(Changzhou)-Tong(Nantong), Hang(Hangzhou)-Jia(Jiaxing)-Hu(Huzhou), Ning(Ningbo)-Shao(Shaoxing)-Zhou(Zhoushan)etc., which have similar region feature and district join together due to the long-term development of society and economy among these regions.  相似文献   

18.
In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica(LJF), Lessonia nigrescens(LNF), Lessonia trabeculata(LTF), Ascophyllum mackaii(AMF), and Ecklonia maxima(EMF). LJF was less in sulfate content(14.16%) and more in galactose and mannose content(1.08 and 0.68) than the documented early. EMF contained 20%–30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans(1.21–1.41). AMF(162 kDa) and EMF(150 kDa) were the first two largest in molecular weight, which were followed by LJP(126 kDa), LNF(113 kDa) and LTF(105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.  相似文献   

19.
针对地震信号中存在大量环境噪声的问题,基于天然地震事件和人工爆破事件建立初始数据集,利用集合经验模态分解(EEMD)技术对波形信号进行分解、降噪,提取出较纯净的各阶本征模态函数(IMF)分量,然后对前10阶分量分别计算分布熵,即EEMD多尺度分布熵,建立神经网络输入矩阵。应用鲸鱼优化算法(WOA)对自组织特征映射(SOM)神经网络参数(竞争层维数、网络训练次数)进行优化,针对不同训练样本寻找对应的最优参数值以改善模式识别的稳定性,从而提高地震识别率。结果表明,EEMD多尺度分布熵结合WOA-SOM模型可有效识别天然地震和人工地震。  相似文献   

20.
This paper consists of the following topics : (1) Significance of observing lower-latitude auroras. (2) Different kinds of atmospheric luminosity. (3) Chronological catalogues and maps of isochasms for auroral visibility. (4) Analysis of archaco-auroras in low latitudes during earlier centuries. (5) Aurora observing studies since International Geophysical Year (IGY). (6) Concerning prediction of auriora occurrence.  相似文献   

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