碳酸盐对铜离子在黄土中吸持及形态影响的实验研究

选用黄土和重金属Cu为研究对象，通过等温吸持实验和Tessier形态提取实验，研究了碳酸盐对铜离子在黄土中吸持及形态的影响。结果表明：黄土去除碳酸盐后，其吸持铜离子的量大幅度降低；碳酸盐结合态、铁锰氧化物结合态和有机质结合态铜含量明显降低，而可交换态铜含量显著增加。     

添加不同化合态结合的铜离子对其在黄土中吸持及形态的影响

分别以CuSO4和Cu(NO3)2为吸持质，研究了添加不同化合态结合的铜离子在黄土中的等温吸持及形态分布规律。结果表明：黄土吸持铜离子以碳酸盐结合态为主。当铜离子初始浓度较低时，添加不同化合态结合的铜离子对其在黄土中的吸持及碳酸盐结合态没有明显影响；当铜离子初始浓度超过一定值时，添加不同化合态结合的铜离子对其在黄土中的吸持及碳酸盐结合态的影响随铜离子初始浓度的增加而明显增大。添加不同化合态结合的铜离子，其持有量和碳酸盐结合态含量均随土壤浓度的增大而减小。当铜离子初始浓度较低时，添加不同化合态结合的铜离子对其在黄土中的吸持量及碳酸盐结合态含量随土壤浓度的变化影响不大；当铜离子初始浓度超过一定值时，相同初始浓度条件下CuSO4较Cu(NO3)2会造成更大幅度的变化。     

马兰黄土对铜的吸持及其形态变化的影响

采用谐振式紊动模拟装置,模拟了均匀紊动条件下马兰黄土与铜的相互作用及其垂向浓度分布,测定了铜的形态和含量,并用模型ＭＩＮＴＥＱＡ２对平衡形态进行计算分析,投沙量(Ｓ０)范围为５－８００ｋｇ·ｍ３．结果表明,黄土吸持铜的量和水相铜浓度均随投沙量的增加而快速下降．在投沙量１００－２００ｋｇ·ｍ３处,固液两相铜的浓度发生突变．黄土上的铜以碳酸盐结合态为主,达９２%以上,表明铜的吸持过程可能以沉淀为主．模型计算结果进一步证实,无论是高浓度还是低浓度泥沙,黄土吸持铜的过程主要以沉淀为主,但高浓度和低浓度的沉淀组成及其比例不同,Ｓ０＜１００ｋｇ·ｍ３时为Ｃｕ４(ＯＨ)６ＳＯ４,Ｓ０＞１００ｋｇ·ｍ３时为Ｃｕ２(ＯＨ)２ＣＯ３．实验分析和模型计算都表明,由于马兰黄土富含１０%以上的碳酸钙而使体系的ｐＨ值升高,高浓度泥沙因此具有更强的以沉淀为主的吸持铜的能力。     

合成雪硅钙石净化含Hg~(2+)废水的实验

考察了雪硅钙石对水中的重金属Hg2+离子的吸附性能,通过单因素实验及正交实验,研究了试水的pH值、初始浓度、吸附时间、吸附温度等因素对雪硅钙石吸附Hg2+反应的影响,确定了优化吸附条件.测定了雪硅钙石对Hg2+的吸附等温线,并用Langmuir吸附等温式进行了拟合,计算了吸附热力学参数,并对其吸附动力学过程进行了分析计算.     

土壤中镉的吸附解吸研究进展

首先概述了国内外关于土壤对镉的吸附解吸的基本研究方法与实验条件。用于吸附解吸实验的土样以通过20目筛为宜，而不同形式的支持电解质及其离子浓度的选择对实验结果有很大影响，应由实验的具体目的和要求确定合适的实验条件。位于土壤颗粒表面的各吸附点位与镉的结合能的能量高低不一，可将土壤对镉的吸附作用区分为专性吸附和非专性吸附。可用传统的或融入新参数的吸附等温线表达土壤对镉的吸附过程，土壤对镉的吸附性能可用综合因子来形容，如吸附势、吸持率、平均分配系数、Langmuir方程的常数k和Freundlich方程的系数k等表达方式，同时寻找这些综合因子与土壤基本理化性质之间的关系。文章最后讨论了影响吸附过程的主要环境因子，并就土壤pH和水分条件的影响机制进行了分析。     

表面活性剂对可离子化有机化合物在黄土中吸附行为的影响

研究了2，4-二氯苯酚、2，4-二硝基苯酚和苯甲酸三种可离子化有机化合物在天然黄土和阳离子表面活性剂改性黄土中的吸附行为。讨论了DH值、离子强度和二价重金属阳离子对可离子化有机化合物在改性黄土中吸附的影响。提出了可离子化有机化合物在改性黄土中的吸附模型，吸附等温曲线可分解为两条分别代表离子和非离子形态的等温吸附曲线；其吸附行为可用双模式吸附理论来解释。在2，4-二硝基苯酚共存时，苯甲酸在改性黄土中的吸附量减小，证明竞争吸附的存在。     

胶团强化超滤中SDS胶团与镉离子的吸附特性

以十二烷基硫酸钠(SDS)作为表面活性剂,对含有Cd2 的水溶液进行胶团强化超滤分离.考察胶团强化超滤中表面活性剂与镉离子比值对镉离子吸附总量、截留率的影响,以及胶团与镉离子的吸附等温规律和吸附动力学规律,并对吸附机理进行了初步探讨.实验结果表明:Cd2 截留率可以达到97%以上,SDS与镉离子的吸附过程符合Langmuir吸附等温方程,并遵循Lagergren二级动力学规律,其吸附作用主要是化学吸附.     

磁性海泡石表面零电荷点和吸附Cd~（2＋）的特性

采用惰性电解质滴定法和静态吸附实验,研究了磁性海泡石表面零电荷点和吸附Cd2＋特性.实验结果表明,海泡石经过磁改性后所对应的pHpzc值由8.0升高到8.5,吸附体系pH的提高,有利于对重金属阳离子Cd2＋的吸附.在pH值大于3时,磁性海泡石对Cd2＋吸附量和去除率随pH值的升高而增大且趋于稳定,其吸附量为16.10 mg.g-1,约为海泡石的3.9倍,去除率为98%,约为海泡石的2.2倍.磁性海泡石对Cd2＋的吸附量与离子强度有较大的相关性,随离子强度的增加而减小;对Cd2＋的吸附量随反应温度的升高而增加,吸附等温式符合Langmuir方程.吸附机理以表面配合吸附和表面沉淀为主.     

马铃薯秸秆生物炭对黄土吸附Cd(Ⅱ)的影响

为了探究来源于本地农业废弃物的生物炭对区域重金属污染黄土吸附固定化修复的可行性,本文采用批量平衡实验法,研究了马铃薯秸秆生物炭、黄土和生物炭与黄土混合物(加炭黄土)吸附重金属Cd(Ⅱ)的性能,考察了吸附时间、初始Cd(Ⅱ)浓度和溶液p H值对吸附过程的影响,并利用红外光谱、X-射线衍射分析等方法对吸附前后的生物炭和黄土分别进行表征.结果表明,生物炭、黄土、加炭黄土对Cd(Ⅱ)的吸附等温模式符合Langmuir模型,在25℃下的最大吸附量分别为15.60、7.87、12.40 mg·g~(-10,吸附动力学数据满足准二级动力学方程,溶液初始p H值对Cd(Ⅱ)的吸附过程影响较大,2p H4和6p H8时,吸附量增加速率很快,而4p H6时,吸附量平缓上升.表征结果说明离子交换和阳离子-π作用为生物炭对Cd(Ⅱ)的主要吸附机制,而黄土对Cd(Ⅱ)的吸附主要归因于石英、高岭石等黏土矿物以及有机质中的羧基基团.对比动力学和等温吸附数据可得,在实验研究范围内,生物炭的添加使黄土对Cd(Ⅱ)的吸附能力分别提高了41.50%和49.94%.因此,在一定条件下,生物炭的输入可有效提高黄土对Cd(Ⅱ)的吸附固定化能力.     

硝化褐煤对铬离子溶液的吸附研究

利用硝酸与龙口褐煤反应制得硝化褐煤，使其有效吸附质腐植酸含量提高。用该湖化褐煤对铬离子进行吸附试验，研究吸附剂的吸附量、吸附动力学、吸附模型和溶液的pH值对吸附的影响。结果表明：硝化褐煤对铬离子具有良好的吸附特性，其静态等温吸附符合Langmuir等温议程。     

Achieving Open Access to Conservation Science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

What Every Conservation Biologist Should Know about Economic Theory

Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.