南麂列岛潮间带底栖藻类与环境的关系探讨

根据南麂列岛的国胜岙,大沙岙和上马鞍等３条潮间带的底栖藻类监测结果,结合同区域的水质及底质环境质量,初步评价了该３个区栖藻类的生态种群,密度,形状及季节变化与环境质量之间的关系。     

Spatial scales and probability based sampling in determining levels of benthic community degradation in the Chesapeake Bay

The extent of degradation of benthic communities of the Chesapeake Bay was determined by applying a previously developed benthic index of biotic integrity at three spatial scales. Allocation of sampling was probability-based allowing areal estimates of degradation with known confidence intervals. The three spatial scales were: (1) the tidal Chesapeake Bay; (2) the Elizabeth River watershed; and (3) two small tidal creeks within the Southern Branch of the Elizabeth River that are part of a sediment contaminant remediation effort. The areas covered varied from 10^–1 to 10⁴ km² and all were sampled in 1999. The Chesapeake Bay was divided into ten strata, the Elizabeth River into five strata and each of the two tidal creeks was a single stratum. The determination of the number and size of strata was based upon consideration of both managerially useful units for restoration and limitations of funding. Within each stratum 25 random locations were sampled for benthic community condition. In 1999 the percent of the benthos with poor benthic community condition for the entire Chesapeake Bay was 47% and varied from 20% at the mouth of the Bay to 72% in the Potomac River. The estimated area of benthos with poor benthic community condition for the Elizabeth River was 64% and varied from 52–92%. Both small tidal creeks had estimates of 76% of poor benthic community condition. These kinds of estimates allow environmental managers to better direct restoration efforts and evaluate progress towards restoration. Patterns of benthic community condition at smaller spatial scales may not be correctly inferred from larger spatial scales. Comparisons of patterns in benthic community condition across spatial scales, and between combinations of strata, must be cautiously interpreted.     

辽河流域典型支流土地利用方式对大型底栖动物群落时空分布特征的影响

通过辽河流域典型支流(清河和凡河)不同土地利用类型区3个水期大型底栖动物及环境因子调查,研究土地利用方式对大型底栖动物分布特征的影响.结果表明,河流大型底栖动物群落四节蜉科(Baetidae)、扁蜉科(Heptageniidae)、纹石蛾科(Hydropsychidae)及石蝇科(Perlidae)等生物类群主要分布在辽河流域内林地为主的河流中;以耕地和居民点为主的土地利用方式下,河流大型底栖动物主要以摇蚊科(Chironomidae)类群为主;颤蚓科(Tubificidae)等寡毛类大型底栖动物在以城市发展为主的土地利用区域内河流中优势明显.河流中大型底栖动物生物多样性、丰富度及EPT%由高到低依次为林地耕地居民点城市,FBI值由低到高依次为林地耕地居民点城市.不同土地利用方式导致河流生境因子空间差异性显著,大型底栖动物群落相似性较低,且生物密度在空间上呈显著差异,但时间上差异不显著.底质、DO与大型底栖动物多样性等指数呈正相关关系,TN、TP、NH3-N、BOD5、CODCr与大型底栖动物生物指数呈不同程度负相关关系.生物与环境联合分析(BIO-ENV)表明,底质、DO、TN、BOD5是影响区域内大型底栖动物群落特征的最显著的主导环境因子.综合上述研究结果可得,土地利用方式通过对河流生境及水质产生影响,进而使大型底栖动物群落组成及多样性特征发生明显变化.     

海河流域河流生态系统健康评价

随着经济发展,人类活动对河流生态系统的胁迫日益强烈,生态系统健康状况受到严重威胁.本研究以海河流域2010年73个采样点的水质、营养盐和底栖动物指标为例,采用指标体系法,从化学完整性和生物完整性两方面评价了流域内河流生态系统健康.结果表明,海河流域河流生态系统健康状况整体较差,有72.6%的样点处于"极差"健康状态,同时表现出明显的地区集聚效应;河流水质与人类活动强度密切相关;海河流域水体富营养化趋势明显;流域内底栖动物多样性低,清洁物种较少.氨氮、总氮、总磷等营养盐指标是影响河流生态系统健康的关键因子,应从控制上述指标入手,遏制海河流域河流生态系统健康恶化.对于河流生态系统健康评价,多因子的综合评价法优于单因子评价法.     

铁岭凡河大型底栖无脊椎动物多样性及BI指数评价

对铁岭凡河8个样点进行了大型底栖无脊椎动物多样性调查研究,共发现类群3门6纲11目28科63属75种。按照BI指数进行评价结果:孤家子、腰寨子、榛子岭水库入口、抚安堡、张搂子样点水体最清洁至清洁;新屯大桥样点清洁至轻污染;榛子岭水库出口、黄河子样点轻污染至中污染。     

云龙湖底栖动物的变化研究

监测分析云龙湖底栖动物种类变化、密度变化,底质组成与变化及生物多样性指数的变化来研究云龙湖水质的变化趋势。研究表明:近5年,云龙湖东湖水质有所改善,西湖富营养化有加重趋势。     

A numerical model of wave- and current-driven nutrient uptake by coral reef communities

We developed a numerical model capable of simulating the spatial zonation of nutrient uptake in coral reef systems driven by hydrodynamic forcing (both from waves and currents). Relationships between nutrient uptake and bed stress derived from flume and field studies were added to a four-component biogeochemical model embedded within a three-dimensional (3-D) hydrodynamic ocean model coupled to a numerical wave model. The performance of the resulting coupled physical-biogeochemical model was first evaluated in an idealized one-dimensional (1-D) channel for both a pure current and a combined wave-current flow. Waves in the channel were represented by an oscillatory flow with constant amplitude and frequency. The simulated nutrient concentrations were in good agreement with the analytical solution for nutrient depletion along a uniform channel, as well as with existing observations of phosphate uptake across a real reef flat. We then applied this integrated model to investigate more complex two-dimensional (2-D) nutrient dynamics, firstly to an idealized coral reef-lagoon morphology, and secondly to a realistic section of Ningaloo Reef in Western Australia, where nutrients were advected into the domain via alongshore coastal currents. Both the idealized reef and Ningaloo Reef simulations showed similar patterns of maximum uptake rates on the shallow forereef and reef crest, and with nutrient concentration decreasing as water flowed over the reef flat. As a result of the cumulative outflow of nutrient-depleted water exiting the reef channels and then being advected down the coast by alongshore currents, both reef simulations exhibited substantial alongshore variation in nutrient concentrations. The coupled models successfully reproduced the observed spatial-variability in nitrate concentration across the Ningaloo Reef system.     

Benthic diatom community response to metal contamination from an abandoned Cu mine: Case study of the Gromolo Torrent (Italy)

Environmental contamination has become a global problem of increasing intensity due to the exponential growth of industrialization. One main debated issue is the metal contamination of rivers receiving Acid Mine Drainage (AMD) from active/abandoned mines. In order to assess the quality of lotic systems, diatoms are commonly used, as their assemblage modifies on the basis of changes in environmental parameters. Benthic diatom changes were analyzed along the metal-impacted Gromolo Torrent (Liguria, NW Italy) with the aim of understanding the effects of input from the abandoned Libiola Cu mine. The results support the hypothesis that metals from AMD lead to massive changes in diatoms, resulting in low biological diversity and in a shift of dominance, passing from the genera Cymbella and Cocconeis to more tolerant and opportunistic species, such as Achnanthidium minutissimum and Fragilaria rumpens. The high concentrations of labile metals, measured through Diffusion Gradients in Thin-films (DGT) immediately downstream of the two AMD inputs in the torrent, corresponded to a sudden decrease in the presence of diatoms, indicating the possible reaching of acute toxic levels. In particular, A. minutissimum dominated the mining area and was positively correlated with Cu and Zn; whereas F. rumpens bloomed downstream of this area, where the metal content was diluted, and was positively correlated with As and Pb. Finally, an important abundance of Nitzschia palea and teratological forms of A. minutissimum and F. rumpens were observed downstream from the mine, indicating that metals may have an important impact on diatoms up to the torrent mouth.     

人为活动对冈曲河大型底栖动物空间分布的影响

为监测人为活动对高海拔山区河流的影响,以香格里拉冈曲河为例,应用多维统计分析与排序分析,探讨大型底栖动物群落对人为活动的响应. 研究表明,冈曲河受到低浓度重金属污染,农业活动和水体富营养化程度相对较轻,总体水质状况符合国家地表水环境质量标准(GB3838—2002)Ⅰ,Ⅱ类水质标准. 聚类分析显示,大型底栖动物群落可分为4组:组Ⅰ(北支翁水河)与组Ⅱ(南支格咱河)采样点受人为活动的影响最轻;组Ⅲ采样点主要受开矿和农业活动影响;组Ⅳ采样点受重金属污染相对较重. 4组采样点在无度量多维标定法(NMS)排序轴上的分布差异明显,组Ⅰ与组Ⅱ采样点体现出空间分布差异,而人为活动主要影响组Ⅲ与组Ⅳ采样点. 随河级增加,底栖动物的群落结构除受到水深、河宽、水温、浊度和海拔高度等环境因子的影响外,组Ⅲ与组Ⅳ采样点影响底栖动物群落退化的主要因素为Cu,Pb和NO-₃-N. 石蛭科和毛缘蛾蚋为组Ⅰ采样点的指示种;叉襀和倍叉襀等敏感类群为组Ⅱ采样点的主要指示种;组Ⅲ的指示种为中耐污种短石蛾和蜉蝣,以及强耐污种寡毛类;涡虫为组Ⅳ采样点的指示种,表明涡虫具有较高的重金属污染耐受性.      

Density and Viscosity Measurements of Natural Solutions

Utilizing sophisticated equipment, densimetric and viscosimetric measurements were carried out on samples of ground-waters of Apulia.

Experimental data, utilized to check if simple equations can evaluate the density and the viscosity of multicomponent solutions, confirm the validity of the hypothesis.