Gradients in coral reef communities exposed to muddy river discharge in Pohnpei,Micronesia     

Yimnang Golbuu  Katharina Fabricius  Steven Victor  Robert H. Richmond 《Estuarine, Coastal and Shelf Science》2008

This study analyzed how coral communities change along a gradient of increasing exposure to a mud-discharging river in the Enipein Catchment, Pohnpei, Micronesia. Using video transects, we quantified benthic communities at five sites along a gradient moving away from the river mouth towards the barrier reef. The most river-impacted site was characterized by a high accumulation of mud, low coral cover and low coral diversity. Although coral cover leveled off at ∼400 m from the river mouth to values found at the outer-most sites, coral diversity continued to increase with increasing distance, suggesting that the most distant site was still impacted by the river discharges. Fungiidae, Pavona, Acropora, Pachyseris and Porites rus all significantly increased in cover with distance from the river, while Turbinaria decreased. The combined presence and abundance of these six species groups, together with coral species richness, may help to indicate the effects of terrestrial runoff in similar runoff-exposed settings around Micronesia, whereas coral cover is not a sensitive indicator for river impact. Coral reefs are important resources for the people of Pohnpei. To prevent further degradation of this important resource, an integrated watershed approach is needed to control terrestrial activities.  相似文献   

Analysis on the indicator species and ecological groups of pelagic ostracods in the East China Sea   总被引：2，自引：1，他引：1  

XU Zhaoli 《海洋学报(英文版)》2008,27(6):83-93

Ecological adaptation and ecological groups of pelagic ostracods were examined in the East China Sea （23°30′-33°00′N, 118°30′ -128°00′E）, in relation to temperature and salinity. The data were collected in four surveys conducted from 1997 to 2000. The density, yield density, or negative exponent models were used to determine the optimal temperature and salinity of water for the thriving growth of pelagic ostracods. Thereafter, ecological groups and potential distribution patterns of pelagic ostracods were determined based on the predicted parameters such as optimal temperature and salinity, consulting the geographic distribution. The analytical results indicate that, among the numerical dominant pelagic ostracods in the East China Sea （ECS）, Euconchoecia aculeata, E. elongata, E. chierchiae, E. maimai, and Cypridina dentata, etc. are offshore subtropical water species. These species are widely distributed in the area, and they can be brought by the warm current to north offshore during spring and winter. The predicated optimal temperature （OT） and optimal salinity （OS） for Paraconchoecia decipiens, P. echinata, P. spini- fera, P. oblonga, Conchoecia magna and Porroeciaporrecta are all greater than 25℃ and 34 separately. These species are mainly distributed in the waters of the Kuroshio, the Taiwan Warm Current, and the Taiwan Strait, and therefore are designated as ocean- ic tropical water species. On the other hand, Pseudoconchoecia concerttrica is considered as offshore subtropical water species based on its geographical distribution although its OT is 19℃. The other species, though their OSs are approximately 34 and with OTs ranging from 20° to 25℃, are considered as offshore subtropical water species because they were found to be widely distributed from the South China Sea to the East China Sea.  相似文献   

Otolith chemical signature and growth of Chaetodon speculum in coastal areas of New Caledonia     

M. Labonne  E. Morize  M. Kulbicki  D. Ponton  L. Marec 《Estuarine, Coastal and Shelf Science》2008

Coral reefs are one of the most diverse ecosystems on Earth. They are currently exposed to increasing levels of anthropogenic perturbations. Several recent reviews point to the lack of good indicators for these perturbations especially to monitor their effects on fish populations or fish assemblages. The SW lagoon of New Caledonia is an ideal location to test indicator species in this context as contrasting sites are present within a small geographical range. This study analysed fish from four sites, one with heavy industrial pollution, another dominated by domestic waste, a third with historic mining activities, and the fourth as a control. The butterfly fish, Chaetodon speculum, was chosen to determine C. speculum's potential as an indicator species due to its link to coral, its sedentary behaviour and its wide geographical distribution. The size distribution, growth rate, age distribution and whole otolith composition were analysed at each site. Age and mean growth rate were analysed from daily increments of the otoliths. The concentrations of eight elements (Li, Mg, Co, Ni, Cu, Rb, Sr, and Ba) were measured by ICP-MS in the otoliths of a subset of individuals. The sites under anthropogenic impact were distinct from the control site by fish size frequencies, age distributions, and the chemical content of their otoliths. The chemical elements Mg, Co, Ni, Cu, and Rb showed differences amongst sites. Fish belonging to the sites furthest from Nouméa could be discriminated in nearly 80% of samples or 60% of the cases when otolith weight or fish age respectively were taken into account. Ni concentrations of the otoliths were also higher in the bays where water concentrations of this element were known to be higher, but these differences were no longer significant once corrected for otolith weight. These results should be mitigated by the fact that: (1) despite significant differences between sites in age distribution and size frequencies there were no differences in growth rates or body condition; (2) differences in age or size were not correlated to perturbation levels; and (3) discrimination between sites based on chemical levels in the otoliths, even though significant, was not sufficient to identify the origin of the fish at a level useful for screening tests. The hypothesis that environmental differences between sites would be reflected in the otolith chemical composition is therefore not fully supported by our results.  相似文献   

Comprehensive evaluation on urban sustainable development of Harbin City in Northeast China   总被引：1，自引：1，他引：0  

Chunmiao Cai  Jincheng Shang 《中国地理科学(英文版)》2009,19(2):144-150

It is an effective way in realizing urban coordinated and sustainable development to establish a series of indicators and to evaluate urban environmental and socioeconomic development. According to the characteristics of Harbin City in Northeast China, an indicator system including five subsystems and 37 indicators was established for comprehensive evaluation on urban sustainable development. The development indexes of all urban subsystems and complex system were calculated quantitatively using the comprehensively integrated methods composed of Principle Component Analysis, Analytic Hierarchy Process and weighed index method, and then the comprehensive level of urban sustainable development and the degree of urban interior coordination were analyzed. The results indicated that 1) the overall urban development presented an uptrend, however, the interior development was not well balanced from 1996 to 2006; 2) the development in each subsystem presented a strong fluctuation; and 3) the development in resources subsystem showed a downtrend. Based on those results, the suggestions of urban sustainable development were put forward at the end.  相似文献   

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郭良迁  马青  杜雪松  孙东颖 《大地测量与地球动力学》2008,28(3):14-20

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高速公路交通事故与气象条件的关系研究     

白永清  何明琼  刘静 《气象与环境科学》2015,38(2):66-71

恶劣天气是高速公路交通事故发生的重要诱因。为了解气象条件对高速公路交通事故的影响程度,基于2006—2008年汉宜高速公路交通事故数据,统计分析了该路段交通事故的月际和日变化特征,利用事故率和日交通事故指数区分定义了交通事故频次和灾害严重程度,采用多项式曲线拟合了气象条件与事故指数的关系,确定了事故突发增长的临界气象指标。结果表明:汛期5—9月是汉宜高速公路交通事故高发时期,冬季其次,春季3—4月及秋季10—11月事故发生较少。高速公路交通事故存在明显日变化特征,03—04时和14—17时为事故高发时段。汉宜高速公路交通事故频率主要受中到大雨和夏季高温天气的影响,事故灾害严重程度主要受强降水和冬季低温天气的影响。大风强降水天气条件下的事故率要高于一般强降水条件下的事故率,夏季潮湿、闷热天气条件下的事故率要高于一般高温天气条件下的事故率。当高速公路沿线平均日雨量达到中到大雨时,事故率达到高峰;当沿线平均雨量超过20 mm时,事故灾害突发严重。当公路沿线平均高温超过33℃时,事故率突发增长;0~3℃的低温对事故灾害程度影响较大。  相似文献   

Prevalence and distribution of fecal indicator organisms in South Florida beach sand and preliminary assessment of health effects associated with beach sand exposure   总被引：2，自引：1，他引：1  

Bonilla TD  Nowosielski K  Cuvelier M  Hartz A  Green M  Esiobu N  McCorquodale DS  Fleisher JM  Rogerson A 《Marine pollution bulletin》2007,54(9):1472-1482

Fecal indicator levels in nearshore waters of South Florida are routinely monitored to assess microbial contamination at recreational beaches. However, samples of sand from the surf zone and upper beach are not monitored which is surprising since sand may accumulate and harbor fecal-derived organisms. This study examined the prevalence of fecal indicator organisms in tidally-affected beach sand and in upper beach sand and compared these counts to levels in the water. Since indicator organisms were statistically elevated in sand relative to water, the study also considered the potential health risks associated with beach use and exposure to sand. Fecal coliforms, Escherichia coli, enterococci, somatic coliphages, and F(+)-specific coliphages were enumerated from sand and water at three South Florida beaches (Ft. Lauderdale Beach, Hollywood Beach, and Hobie Beach) over a 2-year period. Bacteria were consistently more concentrated in 100g samples of beach sand (2-23 fold in wet sand and 30-460 fold in dry sand) compared to 100ml samples of water. Somatic coliphages were commonly recovered from both sand and water while F(+)-specific coliphages were less commonly detected. Seeding experiments revealed that a single specimen of gull feces significantly influenced enterococci levels in some 3.1m(2) of beach sand. Examination of beach sand on a micro-spatial scale demonstrated that the variation in enterococci density over short distances was considerable. Results of multiple linear regression analysis showed that the physical and chemical parameters monitored in this study could only minimally account for the variation observed in indicator densities. A pilot epidemiological study was conducted to examine whether the length of exposure to beach water and sand could be correlated with health risk. Logistic regression analysis results provided preliminary evidence that time spent in the wet sand and time spent in the water were associated with a dose-dependent increase in gastrointestinal illness.  相似文献   

新疆典型干盐湖成钾条件对比与指标模型初探   总被引：3，自引：1，他引：2  

马黎春  刘成林  焦鹏程  陈永志 《矿床地质》2010,29(4):593-601

选取新疆塔里木盆地及准噶尔盆地的2个典型终端干盐湖罗布泊和玛纳斯盐湖,对其成钾条件和模式进行对比分析,分别从盆地地理纬度、构造位置、盆地规模、所处气候带以及区域水文化学特征、盐类矿物组合特征、钾盐富集特征和品位等多个方面进行了研究。罗布泊地区气候干燥指数＞150,补给河流的ρ(K)×10²/ρ(Cl)比值为3.29∶1～5.08∶1,晶间卤水的ρ(K)×10²/ρ(Cl)比值为3.71∶1～6.66∶1,卤水氯化钾品位1.4%,资源量达3.2亿吨。而玛纳斯湖干燥指数为8.63,补给水源的ρ(K)×10²/ρ(Cl)为1.5∶1～12∶1,晶间卤水ρ(K)×10²/ρ(Cl)为0.1∶1～1.6∶1,卤水氯化钾品位0.33%,资源量为37.23万吨。研究结果表明,罗布泊在气候和物源补给上都比玛纳斯湖具有明显优势,有利于形成大型钾盐矿。2个干旱区典型盆地可观察实验的成钾指标对比分析,对于建立蒸发岩盆地成钾指标模型具有重要的参考意义。  相似文献   

小秦岭地区金钼多金属矿成矿特征与找矿预测     

王瑞廷  袁海潮  孟德明  王磊  马文平 《地球科学与环境学报》2014,(1):19-31

小秦岭地区是中国重要的金钼矿产基地。以构造-岩浆-成矿系统为指导,综合研究认为区内金钼多金属矿床可分为印支期—燕山期与重熔型花岗岩浆侵入活动有关的金(钼)矿床成矿系列和与深源浅成型花岗岩、碱性岩有关的钼(金钨)矿床成矿系列。金(钼)矿床类型主要包括石英脉型、构造蚀变岩型、糜棱岩型、爆破角砾岩型和复合型等,以前两者为主;钼(金钨)矿床类型主要包括斑岩型、斑岩-矽卡岩型、斑岩-爆破角砾岩型、石英-碳酸岩脉型和构造蚀变岩型等,也以前两者为主。该区三叠世以来共发生过3次岩浆侵入活动,每次都伴有不同程度的钼金矿化作用,并分别对应于不同的钼金矿化高峰期。钼的成矿作用分为印支期(210~220 Ma)和燕山期早白垩世早期(140~145Ma)、早白垩世中晚期(110~138Ma);金的成矿作用分为印支期(约220Ma)和燕山期早白垩世中晚期(约130Ma);钼、金成矿在印支期和燕山期早白垩世中晚期叠合,而在燕山期早白垩世早期分离。整体上,区内岩体与断裂构造控矿特征明显,燕山期金钼成矿作用强烈发育。该区娃娃沟—峪耳沟、峪耳沟—曹家沟、太子坪—葫芦沟—荒地沟与文公岭北坡等地区为金钼多金属矿的有利找矿靶区,并应特别重视中酸性小岩体的含矿性评价。  相似文献   

Evaluating the fitness for use of spatial data sets to promote quality in ecological assessment and monitoring     

Isabel Pôças  João Gonçalves  Bruno Marcos  Joaquim Alonso  Pedro Castro  João P. Honrado 《International journal of geographical information science》2014,28(11):2356-2371

This article proposes and illustrates a practical methodological framework to evaluate the fitness for use of spatial data sets for environmental and ecological applications, focusing on user requirements for specified application contexts. The methodology is based on the use of metadata to analyze similarity between the data characteristics and the user’s needs or expectations for several quality indicators. Additionally, the concept of ‘critical factors’ is introduced in this framework, allowing users to define which quality indicators have greater importance given their own requirements or expectations and the specified application contexts. The proposed methodology further allows integrating and interconnecting the spatial data quality (SDQ) evaluation methodology with metadata geoportals in WebGIS platforms, facilitating its operation by users from non-spatial disciplines and with often limited expertise on this subject. Examples of the evaluation of fitness for use for specific application contexts within the project BIO_SOS (‘Biodiversity Multi-SOurce Monitoring System: From Space To Species’ FP7 project) are presented. By providing a prompt and straightforward evaluation tool, the proposed methodology can encourage the implementation of SDQ evaluation routines in ecological assessment and monitoring programs, promoting a more adequate use of geospatial data and ultimately contributing to well-supported policy and management decisions.  相似文献