应用灰色模糊马尔科夫链预测海河水质变化趋势

灰色GM(1,1)模型在水质预测中得到了较为广泛的运用,但其存在灰色偏差与抗干扰能力弱的局限性,针对这一问题,将马尔科夫链理论与模糊集合理论引入灰色GM(1,1)预测模型,并应用该模型对海河三岔口断面的DO、CODMn和NH3-N 3项指标2012~2016年的浓度变化趋势进行预测.结果表明,2004~2016年,DO及NH3-N浓度大致呈上升趋势,预计2016年分别可达9.15,1.47mg/L;CODMn浓度呈下降趋势,预计2016年可达3.91mg/L.以2012年的数据做验证,灰色模糊马尔科夫链模型的预测精度最高,可作为科学的水质预测方法.     

牛粪堆肥过程中水溶性有机物演化的光谱学研究

采用紫外-可见吸收光谱、1H-核磁共振(NMR)和同步荧光光谱,研究了牛粪堆肥水溶性有机物(DOM)的结构特征及其演化规律.紫外-可见吸收光谱分析显示,SUVA254由堆肥起始的1.161上升至堆肥结束的2.543;E465/E665在整个堆肥过程中呈现上升趋势,变化范围在2.333~3.500;260~280,460~480,600~700nm范围内的面积积分A1、A2和A3均呈现出先增大后减小的趋势,峰值分别出现在26,14, 14d.1H-NMR分析显示,堆肥0d到堆肥41d,0.5~3.1δ面积积分所占比例从43.06%下降至8.63%,3.1~5.5δ从56.07%上升至89.68%,5.5~10δ不足总体的6%且变化趋势不明显.同步荧光光谱结果显示,经过41d 的堆肥,蛋白质类物质区积分面积比例(APLR)由0.331下降到0.252,而富里酸类物质区积分面积比例(AFLR)由0.325增加到0.336,同时胡敏酸类物质区积分面积比例(AHLR)由0.344增加到0.412;AFLR/APLR比与同步荧光光谱3个荧光峰峰高存在显著相关性,AHLR/AFLR与两个荧光峰光强的比值I351/I284和I382/I351存在显著相关性.上述结果表明,随着堆肥进行, DOM中的非腐殖质物质转化为类腐殖质,同时其芳香性结构增多,碳链结构发生氧化反应,分子量从小变大,堆肥腐殖化程度加大,稳定度增加.     

Occupancy Patterns of Regionally Declining Grassland Sparrow Populations in a Forested Pennsylvania Landscape

Organisms can be affected by processes in the surrounding landscape outside the boundary of habitat areas and by local vegetation characteristics. There is substantial interest in understanding how these processes affect populations of grassland birds, which have experienced substantial population declines. Much of our knowledge regarding patterns of occupancy and density stem from prairie systems, whereas relatively little is known regarding how occurrence and abundance of grassland birds vary in reclaimed surface mine grasslands. Using distance sampling and single‐season occupancy models, we investigated how the occupancy probability of Grasshopper (Ammodramus savannarum) and Henslow's Sparrows (A. henslowii) on 61 surface mine grasslands (1591 ha) in Pennsylvania changed from 2002 through 2011 in response to landscape, grassland, and local vegetation characteristics . A subset (n = 23; 784 ha) of those grasslands were surveyed in 2002, and we estimated changes in sparrow density and vegetation across 10 years. Grasshopper and Henslow's Sparrow populations declined 72% and 49%, respectively from 2002 to 2011, whereas overall woody vegetation density increased 2.6 fold. Henslow's Sparrows avoided grasslands with perimeter–area ratios ≥0.141 km/ha and woody shrub densities ≥0.04 shrubs/m². Both species occupied grasslands ≤13 ha, but occupancy probability declined with increasing grassland perimeter–area ratio and woody shrub density. Grassland size, proximity to nearest neighboring grassland ( = 0.2 km), and surrounding landscape composition at 0.5, 1.5, and 3.0 km were not parsimonious predictors of occupancy probability for either species. Our results suggest that reclaimed surface mine grasslands, without management intervention, are ephemeral habitats for Grasshopper and Henslow's Sparrows. Given the forecasted decline in surface coal production for Pennsylvania, it is likely that both species will continue to decline in our study region for the foreseeable future. Patrones de Ocupación de Poblaciones Regionalmente Declinantes de Gorriones de Pastizales en un Paisaje Boscoso de Pennsylvania     

Shift in Trophic Level of Mediterranean Mariculture Species

The mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming‐up hypothesis (i.e., the increase in the production of high‐trophic‐level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming‐up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming‐up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low‐trophic‐level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds. Cambios en el Nivel Trófico de las Especies de Maricultura Mediterránea     

促进植物生长根圈细菌(PGPR)的研究现状

有机农业提倡与自然共存不破坏平衡,而自然界的土壤中存在许多可促进植物生长的植物根圈微生物(plant growth promoting rhizobacteria,PGPR),此类微生物可分泌促进植物生长的物质,并可诱导植物产生抗性基因,增强植物抗病.PGPR可产生有机物质促进植物生长,改善土壤肥力,增加可溶性磷及铁,诱发植物抗病、克服逆境、增强营养吸收,固氮或防治病害等,在有机农业上有助于植物增产,改善农业对化学肥料的依赖,生产出健康的作物.参25.     

改性腐殖酸对铀的吸附的试验研究

通过静态吸附实验,探讨了改性HA对U(Ⅵ)吸附影响。考查pH值、时间、U(Ⅵ)的初始浓度和温度等对吸附的影响。结果表明:pH值对改性腐殖酸的吸附效果影响较大,改性腐殖酸吸附U(Ⅵ)的最佳pH值为6,最大去除率为99.37%,吸附在60 min内基本达到平衡。UO22+在改性腐殖酸上的吸附是放热过程,符合Freundlich等温吸附方程,相关系数达0.99以上,表明IHA对铀的吸附是以表面为主要吸附位,并不是均匀的单层吸附。图8,参9.     

尖山河小流域土壤可蚀性K值空间变异研究

小流域尺度的土壤可蚀性 K 值空间分异特征及其与土地利用、植被类型、土壤理化性质等相关关系的研究,可以为小流域土壤侵蚀定量研究及综合治理决策提供科学依据。以云南省抚仙湖库区尖山河小流域为研究区,在大密度土壤采样和土壤理化性质测试分析的基础上,采用EPIC模型K值计算方法、地统计学方法和Kriging空间插值方法,计算分析了尖山河小流域土壤可蚀性K值的空间变异特征及土地利用/植被覆盖对K值的影响作用。结果表明,（1）研究区K值变化范围为0.1628-0.3836,均值为0.2824,中值为0.2885,均值与中值相近似,表明K值分布较均匀;变异系数为17.98%, K值存在中等程度的空间变异性。（2）不同土壤质地类型的K值存在一定差异,研究区主要土壤质地类型K值从大到小依次为粉壤〉壤土〉粘壤〉砂壤。（3）研究区以中可侵蚀性（0.25-0.30）、中高可侵蚀性（0.30-0.35）和中低可侵蚀性（0.20-0.25）土壤为主,面积分别为1797.88 hm2、1185.51 hm2和542.32 hm2,分别占小流域总面积的50.76%、33.47%和15.31%,而高可侵蚀性（〉0.35）土壤和较低可侵蚀性（0.15-0.20）土壤分布面积较少,无低可侵蚀性（〈0.15）土壤;在空间分布上,北部高山区土壤具有中低可侵蚀性,中、南部的低海拔区土壤具有中高可侵蚀性,中、南部其余区域土壤具有中可侵蚀性,这种空间分布与海拔存在较强的相关关系。（4）土地利用/植被覆盖对K值具有明显的影响作用,研究区主要土地利用/植被覆盖类型 K 值从小到大依次为林地〈灌草地〈荒草地〈旱平地〈园地〈旱坡地〈水田,需频繁松土、除草、耕作和扰动的土地利用/植被覆盖类型（园地、旱坡地、旱平地和水田）其K值较大,而无需耕作、扰动小的土地利用/植被覆盖类型（林地、荒草地和灌草地）其K值较小,这表?     

入侵植物南美蟛蜞菊营养器官的形态解剖研究

南美蟛蜞菊（Wedelia trilobata（L.）Hitchc.）是华南地区常见的入侵植物之一,其环境适应性强,繁殖速度快,对入侵地生态环境的破坏而导致生物多样性丧失的危害现象已经引起关注。结构与功能的相适应是生物学的基本观点之一,对入侵植物营养器官的内部形态解剖结构的研究,是理解入侵能力与其生物特性之间关系的直接路径,同时也是其他生理机理研究的结构基础。为研究入侵植物南美蟛蜞菊营养器官内部形态结构与其入侵能力的适应性,采用常规徒手切片技术对其根、茎及成熟叶片3大营养器官进行解剖及显微观察。结果表明：南美蟛蜞菊根、茎均具有次生结构。根韧皮部外方薄壁细胞具有分泌道,次生结构横切面中央为发达的次生木质部所填充,周皮代替表皮起保护作用,根的初生生长时期长,具有次生生长可视为其入侵定居时与本地物种形成地下资源和空间竞争的结构基础;茎的初生结构分化不久即产生次生结构,次生结构中央有明显的髓,次生维管束组织产生于初生结构的维管束之间并形成一管状结构明显将皮层和髓分开,茎内部组织高度木质化可视为是其茎直立生长及竞争地上资源和空间的结构基础;叶片为异面叶,上下表皮均具有气孔器和表皮毛,叶片内部具有分泌道,维管束发达且具有束鞘延伸,能与叶片表皮细胞共同构成辅助输导系统,叶片的结构特征是构成其喜阳植物的基础。此外叶片及根分泌道的存在可能与其化感物质的分泌有关。研究结果丰富了南美蟛蜞菊入侵适应性研究的背景基础,同时也弥补其在形态结构研究中的空缺。     

Experimental and computational assessment of 1,4-Dioxane degradation in a photo-Fenton reactive ceramic membrane filtration process

• 1,4-Dioxane was degraded via the photo-Fenton reactive membrane filtration. • Degradation efficiency and AQY were both enhanced in photocatalytic membrane. • There is a tradeoff between photocatalytic degradation and membrane permeation flux. • Degradation pathways of 1,4-Dioxane is revealed by DFT analysis. The present study evaluated a photo-Fenton reactive membrane that achieved enhanced 1,4-Dioxane removal performance. As a common organic solvent and stabilizer, 1,4-Dioxane is widely used in a variety of industrial products and poses negative environmental and health impacts. The membrane was prepared by covalently coating photocatalyst of goethite (α-FeOOH) on a ceramic porous membrane as we reported previously. The effects of UV irradiation, H₂O₂ and catalyst on the removal efficiency of 1,4-Dioxane in batch reactors were first evaluated for optimized reaction conditions, followed by a systematical investigation of 1,4-Dioxane removal in the photo-Fenton membrane filtration mode. Under optimized conditions, the 1,4-Dioxane removal rate reached up to 16% with combination of 2 mmol/L H₂O₂ and UV₃₆₅ irradiation (2000 µW/cm²) when the feed water was filtered by the photo-Fenton reactive membrane at a hydraulic retention time of 6 min. The removal efficiency and apparent quantum yield (AQY) were both enhanced in the filtration compared to the batch mode of the same photo-Fenton reaction. Moreover, the proposed degradation pathways were analyzed by density functional theory (DFT) calculations, which provided a new insight into the degradation mechanisms of 1,4-Dioxane in photo-Fenton reactions on the functionalized ceramic membrane.     

Assessment of heavy metal pollution and health risks in a main river in Huayuan County,Xiangxi, Hunan Province北大核心CSCD

To study heavy metal pollution and assess the health risk of river water in Huayuan County, Xiangxi, Hunan Province, 11 water samples were collected from the Huayuan River and Brother Rivers in August and December 2016. Heavy metal (Pb, Zn, Cr, Cu, Fe, and Ni) concentrations were determined from the samples. The health risk assessment model recommended by the U.S. Environmental Protection Agency (USEPA) was applied to assess the health risk of heavy metals in the main surface waters of Huayuan County. The results indicated that the concentrations of heavy metals (Pb, Zn, Cr, Cu, Fe, and Ni) of surface water in the research area were 2.57 × 10-3, 4.66 × 10-4, 1.65 × 10-3, 6.27 × 10-4, 0.19, and 8.50 × 10-4 mg/L, respectively. The health risk of surface waters with heavy metals was high. Therefore, the chemical carcinogenic substance (Cr) health risk index was five or six times higher than that of chemical non-carcinogens (Pb, Zn, Cu, and Ni). The average health risk indices of non-carcinogenic substances were in the order Pb > Cu > Zn > Ni. The correlation and principal component analysis of surface water showed that the six heavy metal elements were composed of three main components in the main surface waters of the county. The first principal component was comprised of Fe and Ni (33.28%), which was mainly from internal pollution. The second component was comprised of Cu and Cr (26.98%), which was primarily due to industrial waste water, rainwater leaching mineral waste produced by heavy metal mining, and smelting enterprises. The third component, resulting from geochemical pollution, was Zn (17.10%). The health risk indices triggered by heavy metal in surface waters was high. Heavy metal pollutants in the research area need to be controlled in the order Cr, Pb, Cu, Zn and Ni. © 2018 Science Press. All rights reserved.