首页 | 本学科首页   官方微博 | 高级检索  
检索     
共有20条相似文献,以下是第1-20项 搜索用时 93 毫秒

1.  Correlation between Urban Land Change Process and Socioeconomic Development since the 1980s in Jiangsu Province  
   Han Shucheng1  Pu Lijie1  2  Peng Buzhuo1 1. Department of Land Resources and Tourism Sciences  Nanjing University  Nanjing Jiangsu 210093  China   2. Key Laboratory of Land Use  Ministry of Land and Resources  Beijing 100029  China《中国人口.资源与环境(英文版)》,2007年第5卷第2期
   Studying the process and characteristics of urban land change in different phases of urbanization and different economic development is much important for understanding urban land change and management at a macro level. Taking the example of Jiangsu Province, the present paper studied the correlation between urban land change process and socioeconomic development from 1981 to 2003 on the basis of statistical data. The results showed the following three aspects. First, urban land area has changed periodically and the research duration can be divided into two periods: from 1981 to 1994 and from 1995 to 2003. In each period, the changing trend is the same, i.e. slow at first and then quick. Studying from the comprehensive change status, the characteristic of fluctuant change is significant with three acute change pinnacles in 1988, 1991 and 2002 which were corresponded to turning point years of economic development phases of Jiangsu Province respectively. Second, the synchronization between urban land change and urbanization level change is not strict. With the evolution of urbanization phases, the change pace of urbanization level increased remarkably, but urban land change rate did not increase significantly accordingly. Third, the area of urban land has exponentially increased with the increase of per capita GDP. In different economic development levels classified by per capital GDP, land resource cost for economic development is different, respectively 29.01 hm2, 26.34 hm2, 26.22 hm2, and 11.14 hm2 for the increase of 100 million RMB GDP when the per capita GDP is under 1000, 1000–2000, 2000–5000 and over 5000 RMB.    

2.  Identification of a marine woloszynskioid dinoflagellate Biecheleriopsis adriatica and germination of its cysts from southern Chinese coasts  
   Wei Kang  Zhao-Hui Wang《环境科学学报(英文版)》,2018年第66卷第4期
   A strain of small-sized dinoflagellates, isolated from the culture of sediment incubation collected from the coastal areas in southern China, has been identified under microscopical observation and r DNA sequence. Surface sediments from two sea areas in the southern Chinese coastal waters were incubated for 20 and 40 days, and germinated vegetative cells were observed. The cells were identified as species in the Suessiaceae based on the morphological characteristics, ultrastructural features of the cell, as well as its swimming behavior. The studied strain clusters into a well-supported clade together with six sequences of Biecheleriopsis adriatica in the phylogenetic tree based on the large subunit(LSU) rDNA sequence. Therefore, the strain has been identified as B. adriatica based on morphological observation and phylogenetic analysis. B. adriatica was the dominant dinoflagellate species in the germinated phytoplankton community from both sea areas,which contributed 50%–83% to the total germinated dinoflagellates averagely. However,B. adriatica has not been reported in previous phytoplankton surveys, and was probably ignored or misidentified due to its small size and thin wall. The frequent and abundant occurrence of B. adriatica in the germinated phytoplankton community of many sea areas of the southern Chinese coastal waters suggests its wide and abundant distribution in these sea areas.    

3.  Spatial heterogeneity of lake eutrophication caused by physiogeographic conditions: An analysis of 143 lakes in China  被引次数:1
   Jingtao Ding  Jinling Cao  Qigong Xu  Beidou Xi  Jing Su  Rutai Gao  Shouliang Huo  Hongliang Liu《环境科学学报(英文版)》,2015年第27卷第4期
   In order to identify the effect of geographic characteristics on the variations of nutrient concentrations and the utilization efficiency of nutrients by phytoplankton, data from 143 lakes, from 2008 to 2010, including three very different types of topography, i.e., the first topography ladder (FTL), second topography ladder (STL), and third topography ladder (TTL), were statistically analyzed. Lakes in the FTL and STL, located at high elevation (above 1000 m) and low longitudes (lower than 105° E), were sporadically oligotrophic, whereas lakes in the TTL were almost all mesotrophic and eutrophic. The trophic level index (TLI) became higher with the rise of longitude. Two turning points (5 and 15℃) on the curve of TLI as function of the average annual temperature (AAT) corresponded with theAAT in different lake regions in the STL and TTL. Because the responses of TLI toAAT differ significantly, there were variations of nutrient and algal biomass concentrations in different lake regions in the same type of topography ladder. According to the differences in utilization efficiency of total nitrogen or total phosphorus by phytoplankton, China could be partitioned into six lake regions. Scientific nutrient criteria for each lake region shall be established considering these differences in China.    

4.  A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai, China  被引次数:1
   Fengyu Zan  Shouliang Huo  Beidou Xi  Jingtian Zhang  Haiqing Liao  Yue Wang  Kevin M. Yeager《环境科学学报(英文版)》,2012年第24卷第4期
   Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), organic phosphorus (Po), inorganic phosphorus (Pi) and organic carbon and nitrogen stable isotopes (δ13Corg and δ15N) in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of δ13Corg and δ15N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.    

5.  Exploration of relationships between phytoplankton biomass and related environmental variables using multivariate statistic analysis in a eutrophic shallow lake:A 5-year study  被引次数:9
   WANG Xiao-long~《环境科学学报(英文版)》,2007年第8期
   Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions.However,it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity.To elucidate relationships between them,in a eutrophic shallow lake,Taihu Lake,relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity.The results indicate that water temperature and total phosphorus(TP)played governing roles in phytoplankton dynamics in most seasons(i.e.temperature in winter,spring and summer; TP in spring,summer and autumn); COD(chemical oxygen demand)and BOD(biological oxygen demand)presented significant positive relationships with phytoplankton biomass in spring,summer and autumn.However,a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn,and conversely negative ones in summer.As the predatory factor,zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season.Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were observed between phytoplankton biomass and pH,Trans(transparency of water)and DO.The results indicate that interactions between phytoplankton biomass and related environmental variables are highly sensitive to seasonal periodicity,which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability,and hence,advances management methods for eutrophic lakes.    

6.  Exploration of relationships between phytoplankton biomass and related environmental variables using multivariate statistic analysis in a eutrophic shallow lake: A S-year study  被引次数:1
   WANG Xiao-long  LU Yong-long  HE Gui-zhen  HAN Jing-yi  WANG Tie-yu《环境科学学报(英文版)》,2007年第19卷第8期
   Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions. However, it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity. To elucidate relationships between them, in a eutrophic shallow lake, Taihu Lake, relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity. The results indicate that water temperature and total phosphorus (TP) played governing roles in phytoplankton dynamics in most seasons (i.e. temperature in winter, spring and summer; TP in spring, summer and autumn); COD (chemical oxygen demand) and BOD (biological oxygen demand) presented significant positive relationships with phytoplankton biomass in spring, summer and autumn. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn, and conversely negative ones in summer. As the predatory factor, zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season. Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were obser,qed between phytoplankton biomass and pH, Trans (transparency of water) and DO. The results indicate that interactions between phyto:plankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.    

7.  Dynamic phosphorus budget for lake-watershed ecosystems  
   LIU Yong  GUO Huai-cheng  WANG Li-jing  DAI Yong-li  ZHANG Xiu-min  LI Zi-hai  HE Bin《Journal of environmental sciences (China)》,2006年第18卷第3期
   Lake eutrophication caused by excess phosphorus (P) loading from point sources (PS) and nonpoint sources (NPS) is a persistent and serious ecological problem in China. A phosphorus budget, based on material flow analysis(MFA) and system dynamic (SD), is proposed and applied for the agriculture-dominated Qionghai Lake watershed located in southwestern China. The MFA-SD approach will not only cover the transporting process of P in the lake-watershed ecosystems, but also can deal with the changes of P budget due to the dynamics of watershed. P inflows include the fertilizer for agricultural croplands, soil losses, domestic sewage discharges, and the atmospheric disposition such as precipitation and dust sinking. Outflows are consisted of hydrologic export, water resources development, fishery and aquatic plants harvesting. The internal P recycling processes are also considered in this paper. From 1988 to 2015, the total P inflows for Lake Qionghai are in a rapid increase from 35.65 to 78.73 t/a, which results in the rising of P concentration in the lake. Among the total P load 2015, agricultural loss and domestic sewage account for 70.60% and 17.27% respectively, directly related to the rapid social-economic development and the swift urbanization. Future management programs designed to reduce P inputs must be put into practices in the coming years to ensure the ecosystem health in the watershed.    

8.  Seasonal dependency of controlling factors on the phytoplankton production in Taihu Lake, China  
   Qiaohua Zhao  Jing Wang  Jianjian Wang  Julian X.L. Wang《环境科学学报(英文版)》,2019年第76卷第2期
   In this study, 44 profiles of gross primary productivity(GPP) and sunlight, along with water temperature, Chlorophyll-a(Chla) and nutrients, were observed in Meiliang Bay of Taihu Lake, China, in the spring, summer, and fall seasons. Effects of water temperature, light,and nutrient concentration were examined in relation to the GPP-unit-Chla(GPP of algae per Chla). The results showed that the optimum temperature for the GPP of phytoplankton was 27.9°C, the optimal PNA-unit-Chla(photon number absorbed by phytoplankton per Chla) was 0.25(mol), and the HSCN-unit-Chla and HSCP-unit-Chla(half-saturation constants of nitrogen and phosphorus of algae per Chla) were 0.005(mg/L) and 0.0004(mg/L), respectively. The seasonal dependency of the effect of different factors on the GPP was analyzed. Compared with temperature and nutrients, light was found to be the most important factor affecting the GPP during the three seasons. The effect of temperature and nutrients on the GPP of phytoplankton has obvious seasonal change. In spring, temperature was the secondary factor affecting the GPP of phytoplankton, and the effect of nutrients may be negligible in the eutrophic lake on account of temperature limit, which showed that the GPP of algae was only affected by the physical process. In summer and fall, temperature didn't affect the GPP of algae, and the presence of nutrients was the secondary factor affecting the GPP of phytoplankton. From summer to fall, effect of phosphorus was weakened and effect of nitrogen was enhanced.    

9.  Environmental factors influencing cyanobacteria community structure in Dongping Lake, China  被引次数:1
   Xuetang Lu  Chang Tian  Haiyan Pei  Wenrong Hu  Jun Xie《环境科学学报(英文版)》,2013年第25卷第11期
   The present study was conducted to provide a detailed understanding of the variation in cyanobacterial communities of Dongping Lake, which is the final water volume adjusting and storing lake in the east route of the South-to-North Water Diversion Project in China. The spatial and temporal distribution of cyanobacteria was assessed from May 2010 to October 2012 based on monthly samples collected from three stations. Over the 30-month survey, 15 genera and 25 species of cyanobacteria were identified, with cyanobacterial abundance at each monitoring station ranging from undetected to 3.04×107 cells/L, average of 4.27×106 cells/L. The dominant cyanobacterial species were Pseudanabaena limnetica and Aphanizomenon issatschenkoi and not the usual bloom-forming genera such as Microcystis and Anabaena. Cyanobacterial community structure and water quality variables exhibited substantial changes over the period of survey. Redundancy analysis, Pearson correlations, and regression analysis were applied to analyze the relationships among the variables. The results suggested that temperature and chemical oxygen demand were key drivers of the cyanobacterial community composition in Dongping Lake. In addition, the concentration of inorganic nitrogen in the lake had a profound efect on the cyanobacterial abundance as a non-limiting factor in warm periods.    

10.  Temporal and spatial changes in nutrients and chlorophyll-a in a shallow lake, Lake Chaohu, China: An 11-year investigation  
   Libiao Yang  Kun Lei  Wei Meng  Guo Fu  Weijin Yan《环境科学学报(英文版)》,2013年第25卷第6期
   Temporal and spatial changes of total nitrogen (TN), total phosphorus (TP) and chlorophyll-a (Chl-a) in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 μg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN:TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4+ loading from eight major tributaries were in the range of 1.56×104-5.47×104 and 0.19×104-0.51×104 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.    

11.  Short-term e ects of drawing water for connectivity of rivers and lakes onzooplankton community structure  
   WU Zhenbin  LIU Aifen  ZHANG Shiyang  CHENG Shuiping  WU Xiaohui《环境科学学报(英文版)》,2008年第20卷第4期
   During 28–29, September 2005, water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake andNantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration. To evaluate the feasibility and validity ofdrawing water as a means of ecosystem restoration, zooplankton populations were studied 3 times (before, immediately after finishingand a month after drawing water) at seven locations from 27 Sept. 2005 to 2 Nov. 2005. Water quality in the lakes was mostlyimproved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawingwater. Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lakebecause of landform geometry change. Before drawing water, most species in Sanjiao Lake e.g., Brachionus sp. and Keratella sp. weretolerant of contamination. After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged.We conclude that drawing water could be important for improving water quality and favour ecosystem restoration. Dilution of nutrientconcentrations may be an important role in the e ect.    

12.  A case tudy of shallow and eutrophic lakes in China  
   Yin Chengqing  Henz Bemhardt《环境科学学报(英文版)》,1992年第4卷第2期
   The majority of lakes in the eastern part of China are shallow and in various stages of decaying.Chaohu Lake is a typical example and was chosen as a case study in the Cooperative Ecological Research Project(CERP).Through various observations and sample analyses,the environmental impact of heavy nutrient load was assessed,and a multi-dimensional picture of the eutrophication state was obtained.Chaohu Lake is in hypertrophk state and has many typical symptoms:high concentrations ofphosphorus and nitrogen,frecluent algal bloom,dominance of bluegrecn algae,high content of chlorophyll-a,low Secehi Disk depth and abnormal siltation of the lake.The lake pollution is still developing and in recent years has affected the city water supply and the regional economy.    

13.  Assessment of heavy metal enrichment and its human impact in lacustrine sediments from four lakes in the mid-low reaches of the Yangtze River, China  被引次数:1
   Haijian Bing  Yanhong Wu  Enfeng Liu  Xiangdong Yang《环境科学学报(英文版)》,2013年第25卷第7期
   Sediments from four lakes in the mid-low reaches of the Yangtze River, Taibai Lake, Longgan Lake, Chaohu Lake and Xijiu Lake, were chosen to evaluate their enrichment state and history. The state of heavy metal enrichment was at a low level in the sediment of Taibai Lake and Longgan Lake. The enrichment state of Co, Cr and Ni was also low in the sediment of Chaohu Lake and Xijiu Lake, while Cu, Pb and Zn enrichment reached a higher level. Mass accumulation fluxes were calculated to quantitatively evaluate the anthropogenic contribution to heavy metals in the sediment. The anthropogenic accumulation fluxes were lower in the sediment of Taibai Lake and Longgan Lake compared with the other two lakes, where heavy metals, especially Cu, Pb and Zn, were mainly from anthropogenic sources. Heavy metal accumulation did not vary greatly in the sediment of Taibai Lake and Longgan Lake, while that in Chaohu Lake and Xijiu Lake increased since the 1950s and substantially increased since the 1980s, although a decrease occurred since 2000 AD in Xijiu Lake. Heavy metal enrichment was strongly related to human activities in the catchment. The development of urbanization and industrialization was much more rapid in the catchments of Chaohu Lake and Xijiu Lake than of the other two lakes, and thus large amounts of anthropogenically sourced heavy metals were discharged into the lakes, which resulted in a higher contamination risk. However, human activities in the Longgan Lake and Taibai Lake catchments mainly involved agriculture, which contributed a relatively small portion of heavy metals to the lakes.    

14.  Decrease of NH4+-N by bacterioplankton accelerated the removal of cyanobacterial blooms in aerated aquatic ecosystem  
   Xi Yang  Ping Xie  Zhimei M  Qing Wang  Huihui Fan  Hong Shen《环境科学学报(英文版)》,2013年第25卷第11期
   We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) fingerprinting. Chemical analysis and nitrogen dynamic changes illustrated that NH4+-N was nitrified to NO2-N and NO3-N by bacterioplankton. Finally, NH4+-N was exhausted and NO3-N was denitrified to NO2-N, while the accumulation of NO2-N indicated that bacterioplankton with completely aerobic denitrification ability were lacking in the water samples collected from Lake Taihu. We suggested that adding completely aerobic denitrification bacteria(to denitrify NO2-N to N2)would improve the water quality. PCR-DGGE and sequencing results showed that more than 1/3 of the bacterial species were associated with the removal of nitrogen, and Acidovorax temperans was the dominant one. PCR-DGGE, variation of nitrogen, removal efciencies of chlorophyll-a and canonical correspondence analysis indicated that the bacterioplankton significantly influenced the physiological and biochemical changes of cyanobacteria. Additionally, the unweighted pair-group method with arithmetic means revealed there was no obvious harm to the microecosystem from aeration. The present study demonstrated that bacterioplankton can play crucial roles in aerated ecosystems, which could control the impact of cyanobacterial blooms in eutrophicated fresh water systems.    

15.  Seasonal dynamics of water bloom-forming Microcystis morphospecies and the associated extracellular microcystin concentrations in large, shallow, eutrophic Dianchi Lake  
   Yanlong Wu  Lin Li  Nanqin Gan  Lingling Zheng  Haiyan M  Kun Shan  Jin Liu  Bangding Xiao  Lirong Song《环境科学学报(英文版)》,2014年第26卷第9期
   The increasing occurrence of Microcystis blooms is of great concern to public health and ecosystem due to the potential hepatotoxic microcystins (MCs) produced by these colonial cyanobacteria. In order to interpret the relationships between variations of Microcyst/s morphospedes and extracellular MC concentrations, the seasonal dynamics of phytoplankton community composition, MC concentrations, and environmental parameters were monitored monthly from August, 2009 to July, 2010. The results indicated that Microcystis dominated total phytoplankton abundance from May to December (96%--99% of total biovolume), with toxic Microcystis viridis and non-toxic Microcystis wesenbergii dominating after July (constituting 65%- 95% of the Microcystis population), followed by M. viridis as the sole dominant species from November to January (49%--93%). Correlation analysis revealed that water temperature and nutrient were the most important variables accounting for the occurrence ofM. wesenbergii, while the dominance ofM. viridis was related with nitrite and nitrate. The relatively low content of MCs was explained by the association with a large proportion of M. viriclis and M. wesenbergii, small colony size of Microcystis populations, and low water temperature, pH and dissolved oxygen. The extracellular MC (mean of 0.5 ± 0.2 μg/L) of water samples analyzed by enzyme-linked immunosorbent assay (ELISA) demonstrated the low concentrations of MC in Dianchi Lake which implied the low potential risk for human health in the basin. The survey provides the first whole lake study of the occurrence and seasonal variability of Microcyst/s population and    

16.  Growth characteristics of algae during early stages of phytoplankton bloom in Lake Taihu, China  被引次数:1
   Yuhong Ji  Johnson Dan  Min Zhang  Fanxiang Kong《环境科学学报(英文版)》,2013年第25卷第2期
   Three treatments, sediment plus lake water (S+W), sterilized sediment plus lake water (SS+W), and sediment plus filtered lake water (S+FW), were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages: Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S+W, in Stage I, SS+W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS+W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS+W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored.    

17.  Human impact recorded in the sediment of Honghu Lake, Hubei, China  被引次数:1
   YAO Shu-chun  XUE Bin  XIA Wei-lan《环境科学学报(英文版)》,2006年第18卷第2期
   Vertical profiles of the total organic carbon (TOC), total nitrogen (TN), phosphorus, susceptibilities, elements and partical size were analyzed in a short ^137Cs-dated sediment core collected from Honghu Lake, China. The average sedimentation rate was 1.55 mm/a. The results indicated that trophic status of Honghu Lake in the historical period had experienced three stages. Before 1840 the lake was characterized with lower productivity, TOC was less than 9.92 g/kg; TN was 0.902 to 1.24 g/kg. During about 1840-1950, population increased quickly, there was an obvious change in TOC with an average of 13.0 g/kg. Since 1950, human impacts have accelerated the lake eutrophication and nutrients enriched in the sediment with TOC of 21.7 to 93.1 g/kg, TN of 1.77 to 8.78 g/kg. The heavy metal concentration profiles presented similar distribution trends except Pb .and Mn. The results from elements analyses indicated that Honghu Lake had not been polluted by heavy metals except lead.    

18.  Effects of elevated CO2 on sensitivity of six species of algae and interspecific competition of three species of algae  
   YU Juan  TANG Xue-xi  TIAN Ji-yuan  ZHANG Pei-yu  DONG Shuang-lin《Journal of environmental sciences (China)》,2006年第18卷第2期
   Effects of elevated CO, (5000 μl/L) on sensitivity comparison of six species of algae and interspecific competition of three species of algae were investigated. The results showed that, the cell densities of six species of algae grown in elevated CO2 significantly increased compared to those in ambient CO2 (360 μl/L), and with the time prolonged, the increasing extent increased. Therefore, elevated CO2 can promote the growth of six species of algae. However, there were differences in sensitivity between six species of algae. Based on the effects of elevated CO2 on biomass, the sensitive order (from high to low) was Platymanas sp., Platymanas subcordiformis, Nitzschia closterium, Isochrysis golbana Parke 8701, Dunoliella salina, Chlorella sp., on the condition of solitary cultivation. Compared to ambient CO2, elevated CO2 promoted the growth of three species of algae, Platymanas subcordiformis, Nitzschia closterium and Isochrysis galbana Parke 8701 under the condition of mixed cultivation. The sensitivity of the three species to elevated CO2 in mixed cultivation changed a lot compared to the condition of solitary cultivation. When grown in elevated CO2 under the condition of mixed cultivation, the sensitive order from high to low were Nitzschia clostertium, Platymonas subcordiformis; and Isochrysis galbana Parke 8701. However, under the condition of solitary cultivation, the sensitive order in elevated CO2 was Isochrysis galbana Parke 8701, Nitzschia clostertium, Platymonas subcordiformis, from sensitive to less sensitive. On the day 21, the dominant algae, the sub-dominant algae and inferior algae grown in elevated CO2 did not change. However, the population increasing dynamic and composition proportion of three algal species have significantly changed.    

19.  Three-dimensional eutrophication model and application to Taihu Lake, China  被引次数:5
   MAO Jingqiao  CHEN Qiuwen  CHEN Yongcan《环境科学学报(英文版)》,2008年第20卷第3期
   Taihu Lake, the largest freshwater shallow lake in eastern China, has suffered from severe eutrophication over the past two decades. This research developed a three-dimensional eutrophication model to investigate the eutrophication dynamics. The model fully coupled the biological processes and hydrodynamics, and also took into account the effects of sediment release and the external loads from the tributaries. After sensitivity analyses, the key parameters were defined and then calibrated by the field observation data. The calibrated model was applied to study the seasonal primary productions and its regional differences. The comparisons between model results and field data in year 2000 indicated that the model is able to simulate the eutrophication dynamics in Taihu Lake with a reasonable accuracy. From the simulation experiments, it was found that the meteorological forcing have significant influences on the temporal variations of the eutrophication dynamics. The wind-induced circulation and sediment distribution play an important role in the spatial distribution of the algae blooms.    

20.  Influence of dissolved organic matter character on mercury incorporation by planktonic organisms:An experimental study using oligotrophic water from Patagonian lakes  
   Mar&#;a C. Di&#;guez  Claudia P. Queimali&#;os  Sergio Ribeiro Guevar  Mark Marvin-DiPasquale  Carolina Soto C&#;rdenas  Mar&#;a A. Arrib&#;re《环境科学学报(英文版)》,2013年第25卷第10期
   Ligands present in dissolved organic matter (DOM) form complexes with inorganic divalent mercury (Hg^2+) affecting its bioavailability in pelagic food webs. This investigation addresses the influence of a natural gradient of DOM present in Patagonian lakes on the bioaccumulation of Hg^2+ (the prevailing mercury species in the water column of these lakes) by the algae Cryptomonas erosa and the zooplankters Brachionus calyciflorus and Boeckella antiqua. Hg^2+ accumulation was studied through laboratory experiments using natural water of four oligotrophic Patagonian lakes amended with^197Hg^2+. The bioavailability of Hg^2+ was affected by the concentration and character of DOM. The entrance of Hg^2+ into pelagic food webs occurs mostly through passive and active accumulation. The incorporation of Hg^2+ by Cryptomonas, up to 27% of the Hg^2+ amended, was found to be rapid and dominated by passive adsorption, and was greatest when low molecular weight compounds with protein-like or small phenolic signatures prevailed in the DOM. Conversely, high molecular weight compounds with a humic or fulvic signature kept Hg^2+ in the dissolved phase, resulting in the lowest Hg^2+ accumulation in this algae. In Brachionus and Boeckella the direct incorporation of Hg from the aqueous phase was up to 3% of the Hg^2+ amended. The dietary incorporation of Hg^2+ by Boeckella exceeded the direct absorption of this metal in natural water, and was remarkably similar to the Hg^2+ adsorbed in their prey. Overall, DOM concentration and character affected the adsorption of Hg^2+ by algae through competitive binding, while the incorporation of Hg^2+ into the zooplankton was dominated by trophic or dietary transfer.    

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号