2,4-Dichlorophenoxyacetic acid (2,4-D) photodegradation on WO3-TiO2-SBA-15 nanostructured composite

Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide...     

Structure of a Mediterranean cryptobenthic fish community and its relationships with habitat characteristics

In the last 10 years, several studies have been carried out on the fish fauna of the Ustica Island marine reserve, yet no investigation was specifically addressed to the cryptobenthic fish assemblage. The first task of this study, conducted along the shallow rocky reefs of Ustica, was to determine the species composition, diversity and relative density of the resident cryptobenthic fishes. Furthermore, we aimed to assess the effects of some macro- and microscale habitat characteristics on the distribution pattern of fishes. In particular, the effect of predator density was indirectly evaluated by comparing density data collected within and outside the integral reserve zone. Overall, 20 species belonging to Blenniidae, Gobiidae, Tripterygiidae, Scorpaenidae and Gobiesocidae were recorded. Gobius bucchichi, Scorpaena maderensis, Tripterygion delaisi, T. melanurus and T. tripteronotus were the numerically dominant and most common species. The effects of zone (i.e. of predator density), bottom type and depth on species richness, diversity and evenness were not significant. A greater total fish density was observed on stones compared with rocky cliff and plateau, but only in the shallowest depth range. At level of single species, G. bucchichi was more abundant inside than outside the integral reserve, but only on stones and at 0–2 m depth range. Density of G. bucchichi was generally higher on stones than on rocky cliffs or plateau and between 0 and 5 m depth, although these differences were not always significant. T. delaisi was conversely more abundant in the deepest stratum (7–10 m). Canonical analyses demonstrated that bottom type and depth influenced significantly the fish assemblage structure. The observed differences in the assemblage structure relied mainly upon the dominant species. T. tripteronotus was mainly associated with rocky plateau and the intermediate depth range (3–5 m), whereas S. maderensis, T. melanurus and Lipophrys trigloides inhabited preferentially the rocky cliffs. At microscale level, the habitat choice of the investigated species was almost entirely based on whether the substrate was either vegetated or composed of bare rock. T. delaisi and T. tripteronotus were associated with substrata covered by algae, whilst G. bucchichi, S. maderensis and T. melanurus preferred bare rock bottoms. In some species, the electivity indices for the less abundant type of cover, measured at different spatial scale, changed accordingly. For instance, the smaller the size of the sampled area, the higher was the intensity of the association between G. bucchichi and Anemonia viridis.     

On-line speciation of arsenical compounds in fish and mussel extracts by HPLC-ICP-MS

The separation and determination of sub-μmol/l levels of six environmentally significant As compounds was accomplished by means of high performance liquid chromatography (HPLC) combined online with inductively coupled plasma mass spectrometry (ICP-MS). The species of interest (arsenite and arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine) were quantified in fish and mussel extracts after separation on a Dionex AS7 column equipped with an on-guard AG7 column using a bicarbonate buffer as the mobile phase in a gradient mode. The species thus eluted were directly forwarded to the ICP-MS detector. The detection power of the overall system allows each As form to be determined at concentrations as low a 0.0013–0.0027 μmol 1⁻¹.     

The Influence of Linear Elements on Plant Species Diversity of Mediterranean Rural Landscapes: Assessment of Different Indices and Statistical Approaches

This paper mainly aims to study the linear element influence on the estimation of vascular plant species diversity in five Mediterranean landscapes modeled as land cover patch mosaics. These landscapes have several core habitats and a different set of linear elements -habitat edges or ecotones, roads or railways, rivers, streams and hedgerows on farm land- whose plant composition were examined. Secondly, it aims to check plant diversity estimation in Mediterranean landscapes using parametric and non-parametric procedures, with two indices: Species richness and Shannon index.Land cover types and landscape linear elements were identified from aerial photographs. Their spatial information was processed using GIS techniques. Field plots were selected using a stratified sampling design according to relieve and tree density of each habitat type. A 50×20 m² multi-scale sampling plot was designed for the core habitats and across the main landscape linear elements. Richness and diversity of plant species were estimated by comparing the observed field data to ICE (Incidence-based Coverage Estimator) and ACE (Abundance-based Coverage Estimator) non-parametric estimators.The species density, percentage of unique species, and alpha diversity per plot were significantly higher (p < 0.05) in linear elements than in core habitats. ICE estimate of number of species was 32% higher than of ACE estimate, which did not differ significantly from the observed values. Accumulated species richness in core habitats together with linear elements, were significantly higher than those recorded only in the core habitats in all the landscapes. Conversely, Shannon diversity index did not show significant differences.     

Application of a systemic approach to the study of pollution of the Tinto and Odiel rivers (Spain)

The province of Huelva in the SW of Spain presents high environmental contrasts: together with the great abundance of natural spaces, it shows the impacts of historical natural resources exploitation processes. In the Ria of Huelva, the effluents of the chemical industries must be added to the contaminating inputs of the Tinto and Odiel rivers, coming from the acid drainage of the mines located in the Iberian Pyrite Belt. This forced the Environmental Agency (AMA) to elaborate in 1987 an Effluent Remediation Plan in order to negate unacceptable environmental impacts. The application of a grey box systemic analysis to the AMD pollution, undergone by the Tinto and Odiel rivers has allowed to set a conclusive explanation of the sampling results observed for a period of 11 years, thus making available an overall view of the polluting process and, above all, an explanation of its partial aspects.     

城市植物多样性空间分布特征及其保护

概述城市化对生物多样性的影响,着重分析城市植物多样性空间分布特征,在此基础上提出了城市植物多样性保护的策略.     

深入认识生态承载力的空间构成发展节约化畜牧业的初探

内蒙古自治区位于祖国北部边疆，地域辽阔，是我国北疆的绿色屏障，由于自然条件的制约，草场保护与草地资源利用间的矛盾比较突出。近几年我区的过度放牧和养殖，使草地面积退化，而且草地建设严重滞后。我区有得天独厚的风能和水资源，但资源分布不均，东部地区水资源和草地资源丰富，而中西部地区风能资源丰富，如何充分认识与利用资源空间有机组成，充分利用生态承载力，实现生存与生态良性发展，则显得十分重要。本文要结合我区的风、水、土、草等资源的分布条件，探讨我区走协调发展的道路。     

臭氧氧化法处理汽车制造厂综合废水的试验研究

汽车制造厂综合废水因含有多种有机物和有毒物故可生化性差，因此有必要对其进行生物降解和脱毒处理，鉴于臭氧是一种高效氧化剂且工业废水中的许多污染物具有较好的可氧化性，研究采用臭氧对雷诺汽车制造公司法国某分厂的综合废水进行氧化处理实验，以提高其可生化性。实验结果表明臭氧氧化法可以用来改善汽车制造厂综合废水的可生化性。     

改进灰色系统模型在城市噪声预测中的应用

把城市噪声作为一个灰色系统,分别通过GM(1,1)模型和改进灰色系统模型GM'(1,1),对城市噪声进行预测,并进行精度检验.改进的灰色系统模型GM'(1,1)在精度上均优于GM(1,1)模型,但是GM'(1,1)在计算上比较复杂,需要通过计算机迭代来实现.