太湖部分沉积物中多环芳烃生态风险评估

对2009年12月采集的部分太湖表层沉积物中多环芳烃类化合物（PAHs）的现状进行调查和研究,结果表明,太湖流域表层沉积物中共检出属于美国优先控制16种PAHs中的9种,各采样点位PAHs浓度范围在264.9—1703.2 ng·g-1之间.分析显示,表层沉积物中以4环及4环以上PAHs为主,两者之和约占PAHs总量的...     

珠江水体表层沉积物中PAHs的含量与来源研究

沿珠江白鹅潭水域及大学城官州河流域设立6个采样点,利用沉积物捕获器收集沉积物。参照美国EPA8000系列方法及质量保证和质量控制,对各采样点表层沉积物中16种多环芳烃（polycyclic aromatic hydrocarbons,PAHs）进行分析,以阐明珠江广州河段表层沉积物中PAHs的含量和分布特征,并结合特征化合物指数对其来源作初步探讨。珠江广州河段表层沉积物中PAHs总量介于4 787.5～8 665 ng·g^-1,平均值为7 078 ng·g^-1,黄沙码头河涌出口沉积物中总量为最高（8 665 ng·g^-1）,芳村码头为最低（4 787.5 ng·g^-1）。16种多环芳烃中菲、荧蒽、芘含量较高,分别占PAHs总量的16.11%、14.47%和17.77%。特征化合物荧蒽/202比值均小于0.5,茚并[1,2,3-cd]芘/276比值均大于0.2,表明珠江广州段表层沉积物中PAHs主要来源于化石燃料的不完全燃烧。     

多环芳烃(PAHs)污染对滨海湿地入侵植物互花米草的影响北大核心CSCD

滨海湿地生态系统正遭受着人为活动或自然因素的威胁,为探究多环芳烃（PAHs）污染对滨海湿地入侵植物互花米草根际、根内微生物的影响及植物-微生物联合修复PAHs的潜力,设置含有不同浓度菲和芘的沉积物处理,通过盆栽实验对互花米草幼苗进行暴露.结果显示,培养70 d后,菲和芘的去除率分别为13%-36%和11%-30%;菲处理的互花米草根际沉积物中脱氢酶活性显著高于对照（P〈0.05）,非根际沉积物多酚氧化酶活性则降低10%.磷脂脂肪酸（PLFA）分析显示,菲处理显著降低了根际沉积物微生物量（P〈0.05）,尤其是革兰氏阴性菌下降了24%;而芘处理对脱氢酶、多酚氧化酶以及总微生物量的影响相对较小.100 mg/kg菲处理使得根际与根内革兰氏阴性菌PAHs-环羟基双加氧酶基因（PAH-RHDα-GN）丰度比对照组分别增加了100倍和3倍;而100 mg/kg芘处理使得根际与非根际沉积物中PAH-RHDα-GP丰度显著升高（P〈0.05）.上述结果表明,入侵植物互花米草对PAHs污染存在明显的响应,其根内细菌在植物-微生物联合修复PAHs污染具有重要的作用.     

京杭大运河苏南城市段表层沉积物铜、锌吸附特征及理论环境安全吸附容量

应用等温吸附法研究京杭大运河苏南三城市段（常州、苏州和无锡）表层沉积物对Cu和Zn的吸附行为,并结合国家地表水环境质量标准（GB3838—2002）,估算运河城市段表层沉积物对Cu和Zn的理论环境安全吸附容量（QⅢ）。结果表明：大运河表层沉积物的Cu和Zn等温吸附符合Langmuir模型;表层沉积物Cu最大吸附量（Cu-Qmax）为5.20～9.03 mg·g-1,Zn最大吸附量（Zn-Qmax）为2.40～5.07 mg·g-1;最大吸附量与沉积物的性质密切相关,但与总有机碳质量分数无关。根据Langmuir拟合方程估算,在我国地表水环境质量标准三类水标准阈值时,Cu的理论环境安全吸附容量为沉积物总Cu量的19倍以上,而Zn则为2～6倍。因此,Zn对三城市段大运河沉积物的环境风险要高于Cu。     

沉积物不同天然有机组分对氨氮吸附特征的影响

为估算沉积物不同天然有机组分吸附态氨氮携载量．采用平衡吸附法研究西辽河沉积物不同天然有机组分对氨氮吸附特征的影响。结果表明,去除有机质后的沉积物对氨氮的吸附能力大大降低,其碳标化饱和吸附量（Гmoc）和吸附分配系数（Koc）分别为重组的55．30％和69．49％,说明有机质是影响氨氮在沉积物上吸附特征的主要因素。氨氮在轻组有机组分上的吸附以分配作用为主（Koc=85．57）;稳结态和紧结态腐殖质是形成沉积物疏松多孔团聚体结构的重要胶结物质,氨氮在重组有机组分上的吸附除分配作用外,还存在孔隙填充方式的吸附;重组有机组分中的紧结态腐殖质（胡敏素）对氨氮吸附起关键作用（Гmoc,=5857．78mg·kg-1）。轻组有机质、稳结态腐殖质和紧结态腐殖质携载的吸附态氨氮可分别按重组（Гmoc=3477．81mg·kg-1）的0．32、1．21和1．68倍估算。关键词：沉积物;天然有机组分;氨氮;吸附;碳标化吸附分配系数;碳标化饱和吸附量     

微生物对水-沉积物中苯并[a]芘-镉复合污染修复的研究

从广东汕头贵屿镇的沉积物中分离得到1株对PAHs有较好降解能力且有较强重金属耐受性的菌株（简称B4）,菌种鉴定表明该菌为氧化节杆菌属。以土著微生物、处理方式、沉积物、修复时间等为不同的影响因子对该菌修复水体/沉积物中苯并[a]芘（BaP）-镉（Cd）复合污染进行了初步研究。结果表明：该菌同时具有降解BaP和吸附Cd的性能;土著微生物对BaP有一定的降解能力,并能显著促进B4降解BaP,当体系中BaP质量浓度为1.00 mg.L-1时,降解率达到了68.3%;Cd的吸附却因土著微生物的存在发生一定程度的解吸。振荡培养对BaP的降解效果略优于静止培养修复,而静止修复却更有利于Cd的去除。沉积物促进体系Cd的吸附,却减弱了菌种对BaP的降解。在静止培养修复中,BaP的降解主要发生在7 d以前,降解率保持在35%左右,此时Cd的去除效果亦较好。     

离子强度对土壤与沉积物吸附多环芳烃的影响研究

以黄河三角洲表层沉积物与湿地土壤为对象,研究了离子强度对菲、苯并[a]芘在土壤和沉积物上吸附行为的影响。结果表明:不同Ca2 离子强度下,土壤与沉积物对菲、苯并[a]芘的吸附速率均较快,48h吸附能够达到平衡,Ca2 离子强度对土壤和沉积物影响程度不同;土壤和沉积物的吸附等温线均呈线形,能较好地符合线性方程,可决系数R2在0.98以上,菲的KD值在24~130mL·g-1之间,苯并[a]芘的KD值在3517~5081mL·g-1;随着体系离子强度的增大,土壤与沉积物对PAHs的吸附能力均降低,而且两者之间的吸附量差距明显降低,表明离子强度对土壤影响程度明显大于沉积物。     

不同来源太湖沉积物粒径分布及其对Cu的吸附特征

以不同来源的太湖沉积物为研究对象,利用Mastersizer 2000型激光粒度分析仪测定沉积物的粒度组成,利用筛析法和吸管法对不同来源沉积物进行分级,测定不同粒径沉积物中Cu含量及不同粒径沉积物对Cu2＋的饱和吸附量,研究沉积物对水溶液中Cu（Ⅱ）的吸附特性,从粒径分级和动力学角度探讨了太湖沉积物对Cu的吸附机理。结果表明：太湖沉积物粒径范围在0.002-0.1 mm,其颗粒组成以粉砂级与粘粒级为主,养殖区沉积物小粒径比例较高,小于0.05 mm粒径沉积物的比例为82.45%;吸附实验研究表明,粒径小于0.005 mm和0.005-0.01 mm沉积物中Cu含量较高,且此粒径沉积物对Cu（Ⅱ）的吸附量最大;吸附动力学研究表明,沉积物的吸附过程分为快反应和慢反应两个阶段,且吸附过程以表面吸附为主,伪二级动力学方程对动力学曲线拟合较好,其R2值达0.999以上。吸附热力学的研究结果表明：Freundlich方程比较适合描述沉积物对Cu2＋的吸附等温线,其R2大于0.99,对照区、养殖区和生活污水区沉积物对Cu（Ⅱ）的最大吸附量分别为229.20,249.98,261.20 mg.kg-1,方程式中的强度因子1/n不适合描述沉积物与重金属离子的结合能力。     

黄河中下游沉积物对磷酸盐的吸附动力学研究

研究了黄河中下游10个不同表层沉积物在黄河水体中对磷酸盐（P）的吸附动力学及其影响因素和吸附机理。结果表明：（1）不同黄河沉积物对P的吸附能力各不相同,但吸附量随时间的变化具有相同的变化趋势,吸附速率均在前8h内较快,以后逐渐趋缓,在48h时基本达到吸附平衡。不同黄河沉积物对P的吸附量均随P初始质量浓度的增加而增大,随沉积物含量增大而减小;（2）不同沉积物在不同P初始质量浓度下对P的吸附动力学均符合Lagergren二级吸附动力学模型及Weber-Morris扩散方程,求得二级吸附速率常数和扩散速率常数分别在11.9866～157.55g·mg^-1·h^-1和0.0005～0.0119mg·g^-1·h^-1/2之间,吸附过程由P在沉积物内扩散控制。     

长江嘉陵江重庆段多环芳烃的分布特征和来源辨析

2014年7月,采集长江嘉陵江重庆段9个断面的地表水和沉积物样品,检测15种多环芳烃(PAHs)含量.结果表明,地表水的∑PAHs浓度范围为65.6—1249 ng·L~(-1),沉积物中∑PAHs浓度范围为68.6—4226 ng·g~(-1),与其历史浓度水平相当;聚类分析表明,化工园区对其下游PAHs分布有一定影响,园区下游地表水和沉积物∑PAHs浓度最高.两江汇流前,地表水4环PAHs占总量的43.63%—61.68%;两江汇流后,2环比例增加,占总量的29.01%—68.72%;沉积物4环PAHs占总量的26.62%—48.74%.在顺流方向,地表水中河左∑PAHs浓度高于河中和河右,沉积物中∑PAHs浓度横向无明显差别,其中化工园区下游可能是受左岸工业影响,地表水中河左∑PAHs浓度是河中、河右的12倍和7倍,沉积物中河左∑PAHs浓度是河右的7倍.环数组成、分子比值和主成分分析表明研究区域地表水PAHs来源主要为木材、煤燃烧源,同时还包括石油燃烧和石油泄漏,沉积物则主要为木材、煤高温燃烧源.     

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.     

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.     

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.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Potential for Electropositive Metal to Reduce the Interactions of Atlantic Sturgeon with Fishing Gear

Atlantic sturgeon (Acipenser oxyrhynchus) populations have been declared either endangered or threatened under the U.S. Endangered Species Act. Effective measures to repel sturgeon from fishing gear would be beneficial to both fish and fishers because they could reduce both fishery‐associated mortality and the need for seasonal and area closures of specific fisheries. Some chondrostean fishes (e.g., sturgeons and paddlefishes) can detect weak electric field gradients (possibly as low as 5 Μv/cm) due to arrays of electroreceptors (ampullae of Lorenzini) on their snout and gill covers. Weak electric fields, such as those produced by electropositive metals (typically mixtures of the lanthanide elements), could therefore potentially be used as a deterrent. To test this idea, we recorded the behavioral responses of juvenile Atlantic sturgeon (31–43 cm fork length) to electropositive metal (primarily a mixture of the lanthanide elements neodymium and praseodymium) both in the presence and absence of food stimuli. Trials were conducted in an approximately 2.5 m diameter × 0.3 m deep tank, and fish behaviors were recorded with an overhead digital video camera. Video records were subsequently digitized (x, y coordinate system), the distance between the fish and the electropositive metal calculated, and data summarized by compiling frequency distributions with 5‐cm bins. Juvenile sturgeon showed clear avoidance of electropositive metal but only when food was present. On the basis of our results, we conclude that the electropositive metals, or other sources of weak electric fields, may eventually be used to reduce the interactions of Atlantic sturgeon with fishing gear, but further investigation is needed. El Potencial del Metal Electropositivo para Reducir las Interacciones del Esturión Atlántico con Instrumentos de Pesca Bouyoucos, Bushnell & Brill 13–003     

The role of time and species identities in spatial patterns of species richness and conservation

Many conservation actions are justified on the basis of managing biodiversity. Biodiversity, in terms of species richness, is largely the product of rare species. This is problematic because the intensity of sampling needed to characterize communities and patterns of rarity or to justify the use of surrogates has biased sampling in favor of space over time. However, environmental fluctuations interacting with community dynamics lead to temporal variations in where and when species occur, potentially affecting conservation planning by generating uncertainty about results of species distribution modeling (including range determinations), selection of surrogates for biodiversity, and the proportion of biodiversity composed of rare species. To have confidence in the evidence base for conservation actions, one must consider whether temporal replication is necessary to produce broad inferences. Using approximately 20 years of macrofaunal data from tidal flats in 2 harbors, we explored variation in the identity of rare, common, restricted range, and widespread species over time and space. Over time, rare taxa were more likely to increase in abundance or occurrence than to remain rare or disappear and to exhibit temporal patterns in their occurrence. Space–time congruency in ranges (i.e., spatially widespread taxa were also temporally widespread) was observed only where samples were collected across an environmental gradient. Fifteen percent of the taxa in both harbors changed over time from having spatially restricted ranges to having widespread ranges. Our findings suggest that rare species can provide stability against environmental change, because the majority of species were not random transients, but that selection of biodiversity surrogates requires temporal validation. Rarity needs to be considered both spatially and temporally, as species that occur randomly over time are likely to play a different role in ecosystem functioning than those exhibiting temporal structure (e.g., seasonality). Moreover, temporal structure offers the opportunity to place management and conservation activities within windows of maximum opportunity.     

Main nutrient compounds in food bodies of Mexican <Emphasis Type="Italic">Acacia</Emphasis> ant-plants

Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive indirect defence mechanism. These plants often produce cellular food bodies (FBs) to nourish their resident ants. Lipids, proteins, and even highly specialised compounds such as glycogen have been reported from FBs, but detailed chemical analyses of FB composition have so far been presented only for Southeast Asian Macaranga and Central American Piper myrmecophytes. Here we report the chemical composition of FBs of five myrmecophytic Acacia (Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS (lipids). Feeding experiments revealed no hints on any use of external food sources by the inhabiting Pseudomyrmex ants. These ants obviously rely completely on FBs and extrafloral nectar provided by their hosts. The total content of nutrients in Acacia FBs was 15-25% of FB dry mass, being much lower than in Macaranga or Piper FBs. Proteins were dominating (8-14 % dm) in Acacia FBs and thus were present in higher amounts than in Macaranga FBs, yet in lower amounts than in Piper. Lipids contributed 1-9 % of dry mass, showing a lower proportion than in FBs of Macaranga or Piper. Carbohydrates made up 3-11 % dm, reaching in most Acacia species the same range as observed in Macaranga and in Piper FBs. Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up a much higher proportion in Acacia FBs than in Macaranga or Piper FBs. Both characters might represent an adaptation to producing FBs unprotected at the leaf tips under dry conditions. Acacia FBs contain all amino acids and all fatty acids that are considered essential for insects, and their contents of lipids and proteins are higher than in the leaves from which they are ontogenetically derived. This indicates a putatively adaptive enrichment of nutritionally valuable compounds in structures functioning as ant-food.     

Examining the uncertain origin and management role of martens on Prince of Wales Island,Alaska

Conservation biologists are generally united in efforts to curtail the spread of non‐native species globally. However, the colonization history of a species is not always certain, and whether a species is considered non‐native or native depends on the conservation benchmark. Such ambiguities have led to inconsistent management. Within the Tongass National Forest of Alaska, the status of American marten (Martes americana) on the largest, most biologically diverse and deforested island, Prince of Wales (POW), is unclear. Ten martens were released to POW in the early 1930s, and it was generally believed to be the founding event, although this has been questioned. The uncertainty surrounding when and how martens colonized POW complicates management, especially because martens were selected as a design species for the Tongass. To explore the history of martens of POW we reviewed other plausible routes of colonization; genetically and isotopically analyzed putative marten fossils deposited in the late Pleistocene and early Holocene to verify marten occupancy of POW; and used contemporary genetic data from martens on POW and the mainland in coalescent simulations to identify the probable source of the present‐day marten population on POW. We found evidence for multiple routes of colonization by forest‐associated mammals beginning in the Holocene, which were likely used by American martens to naturally colonize POW. Although we cannot rule out human‐assisted movement of martens by Alaskan Natives or fur trappers, we suggest that martens be managed for persistence on POW. More generally, our findings illustrate the difficulty of labeling species as non‐native or native, even when genetic and paleo‐ecological data are available, and support the notion that community resilience or species invasiveness should be prioritized when making management decisions rather than more subjective and less certain conservation benchmarks.