溶解氧变化对底泥酶活性及微生物多样性的影响

采用室内静态实验考察了溶解氧变化对底泥酶活性影响,同时采用BIOLOG ECO微平板构造了不同溶解氧水平下底泥微生物多样性指数。结果表明:高溶解氧条件下,底泥多酚氧化酶及过氧化物酶活性显著高于缺氧条件及厌氧条件(P<0.01),脱氢酶活性高于背景值;厌氧条件下脱氢酶、脲酶及碱性磷酸酶活性显著高于高溶解氧组、缺氧组及背景值(P<0.05);缺氧条件下硝酸盐还原酶活性显著高于高溶解氧组及厌氧组(P<0.05);蛋白酶活性受溶解氧水平变化的影响较小。BIOLOG ECO微平板法分析表明,溶解氧变化对底泥微生物多样性有不同程度的负面影响,微生物多样性的降低程度从大到小依次为高溶解氧组>厌氧组>缺氧组。主成分分析结果表明:缺氧条件及厌氧条件下,底泥微生物对大分子有机物的利用出现不同程度的降低,相对地,高溶解氧条件下微生物对大分子有机物的利用程度呈现先下降后上升的趋势;高溶解氧组及缺氧组底泥微生物对碳水化合物利用程度升高,厌氧组对碳水化合物利用程度降低。总之,高溶解氧条件更有利于形成底泥有机物完整的代谢循环,提高大分子有机物的利用程度。     

基于启发式元胞自动机模型的群落演替初期营养级联结效率研究

保护和维持生态系统平衡,非确定性模型的发展使得人们掌握了除确定性模型求解以外的另一条建模途径。在解决生态系统这种复杂系统的问题时,要求我们寻找一种可以满足时空特异性与非线性的途径。群落演替的驱动机制与作用规律是生态研究的一个重要问题,本文通过建立群落演替初期第一第二营养级间相互作用关系的元胞自动机模型研究了营养级联结效率的问题,提出了一种除holling模型以外的捕食者——被捕食者模拟方法,并对各自具有不同特征的生态系统的模拟问题提出了建议。     

蚂蚁扰动对青海湖北岸高寒草甸草原群落结构影响

蚂蚁的筑丘活动是草地生态系统中不可忽视的生物干扰因子。本文针对青海湖北岸高 寒草甸草原,调查了不同大小的蚁丘及其周围对照草地的土壤理化性质和植被状况。结果表明： 蚂蚁筑丘活动显著地降低了土壤容重和土壤湿度,增加土壤温度,但对土壤pH 值的影响较小。 蚂蚁扰动改变了群落组成,增加了大部分禾本科和豆科物种的重要值而降低了杂类草的重要值。 以莎草科的矮嵩草（Kobresia humilis）和禾本科的异针茅（Stipa aliena Keng）、赖草（Leymus secalinus）、溚草（Koeleria cristata）等为主的群落逐步演替为以禾本科的异针茅和赖草为主的 群落。植物群落的盖度降低但其地上、地下生物量增加;植物群落丰富度指数降低但均匀度指 数增加。     

淀山湖浮游藻类群落的早期增长

对2004～2009年淀山湖浮游藻类群落生物量[以叶绿素a（Chla）表示]随时间的变化进行了数学模拟.模拟结果表明,Logistic增长模型能够很好地描述淀山湖浮游藻类群落春季和夏季的早期增长.一般说来,淀山湖春季以硅藻和绿藻为主的浮游藻类群落于2月下旬进入指数级增长,到3月上旬浮游藻类密度已经达到始盛点的2倍,浮游...     

Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone： a case study in Taihu Lake, China

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone （ATE） of Taihu Lake were investigated, and the relations among N, P, ORP （oxidation reduction potential）, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON （dissolved organic nitrogen） and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^＋-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^＋-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.     

Variation of soil fertility and carbon sequestration by planting Hevea brasiliensis in Hainan Island, China

The development of rubber industry depends on the sustainable management of rubber plantation. To evaluate the environmental effects of planting Hevea brasiliensis on a subsystem of tropical forest ecosystem, the variation of soil fertility and carbon sequestration under rubber plantation within 30-year life period were investigated in Hainan Island. Results showed that （1） with the increase of stand age of rubber plantation, soil fertility decreased all along. From 1954 to 1995, soil organic matter, total N, available K and available P decreased by 48.2%, 54.1%, 56.7% and 64.1%, respectively. （2） If the complete return of litters was considered without additional fertilizer application to the soil of the rubber plantations, the consumption periods for P, N, K, Mg were only 825 years, 329 years, 94 years and 65 years, respectively~ To improve soil fertility is essential for rubber plantation development. （3） The C sequestration of rubber trees per hectare accounts for 272.08 t within 30-year life period and 57.91% of them was fixed in litters. In comparison with C sequestration by rain forest （234.305 t/hm^2） and by secondary rain forest （150.203 t/hm^2）, rubber forest has more potentials for C fixation. On the base of above results, the following measures would benefit the maintenance of soil fertility and the development of rubber industry, including applying fertilizer to maintain the balance of soil nutrients, intercropping leguminous plant to improve soil fertility, reducing the collection of litters, optimizing soil properties to improve element P availability such as applying CaCO3. The information gathered from the study can be used as baseline data for the sustainable management of rubber plantation elsewhere.     

T-RFLP方法分析城市污水处理厂中细菌群落的动态变化

采用基于16SrRNA基因的末端限制性片段长度多态性技术(T-RFLP),分析了功能稳定的2个城市污水处理系统中(系统A及系统B),细菌群落结构在105d中的动态变化.在研究中,系统A和系统B功能稳定,BOD出水浓度均在8mg/L左右,总氮(TN)出水浓度分别在25mg/L和23mg/L之下.T-RFLP图谱分析表明,系统A中,115、118、123、471、482和835bp等T-RFs的相对丰度变化显著,系统B中,123、471、750和835bp等T-RFs的相对丰度变化显著.移动窗口分析表明,系统A中细菌群落的平均变化率Δt(15d)为21.5%±5.7%,系统B的平均变化率Δt(15d)为22.6%±5.0%.洛伦兹曲线分析表明,系统A中20%的微生物的累积相对丰度为43%～50%;系统B中20%的微生物的累积相对丰度为47%～52%.结果表明,在城市污水处理厂中,稳定的功能并没有藕联着稳定的细菌群落结构.     

Methanotrophic community structure of aged refuse and its capability for methane bio-oxidation

Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.     

Archaeal community structure along a gradient of petroleum contamination in saline-alkali soil

The impact of petroleum on archaeal community in salinealkali soils was investigated, which will expand the knowledge of the archaeal population involved in the natural attenuation of hydrocarbons in extreme environments.     

彭水电站蓄水前后鱼类群落多样性特征

根据2006-2008年9-10月渔业资源动态监测资料,分析研究了彭水电站蓄水前后坝上和坝下江段鱼类群落结构变化及其生物多样性变化特征.研究结果表明:3次监测中,调查江段出现的鱼类共有9科44属63种,其中长江上游特有鱼类22种;渔获物中,群体数量主要由体重＜50 g的小型鱼类和幼鱼组成,而群体重量主要由＜500g的中...