几种络合态铜对彩虹方头鱼的生物有效性

通过暴露实验和化学形态计算方法研究了彩虹方头鱼(Ｐａｒａｃｈｅｉｒｏｄｏｎｉｎｎｅｓｉ)对四种铜络合物的吸收．结果表明,络合态铜可被彩虹方头鱼吸收,但对络合态铜的吸收率显著低于对非络合态铜的吸收率,在其它形态铜含量基本恒定的条件下,铜吸收量随络合态铜含量的增加而呈线性增加趋势．不同络合态铜的有效性也有显著差别,条件稳定常数越高,则越不容易被吸收．由于铜暴露导致的粘液分泌量的变化从另一侧面证实了络合态铜的可吸收性．     

几种络合态铜对彩虹方头鱼的生物有效性^1）

通过暴露实验和化学形态计算方法研究了彩虹方头鱼（Parcheirocon innesi)对四种铜络合物的吸收,结果表明,络合态铜可被彩虹方头鱼吸收,但对络合态铜的吸收率显著低于对非络合态铜的吸收率,在其它表态铜含量基本恒定的条件下,铜吸收量随合态铜含量的增加而呈线性增加趋势,不同络合态铜的有效性有也显著差别,条件稳定常数越高,则越不容易被吸收,由于铜暴露导致的粘液分泌量的变化从另一侧面证实了络合态铜的可吸收性。     

鲤鱼鱼鳃微环境酸碱条件与铜形态分布模拟

用鱼鳃微环境测定装置和化学平衡计算方法,研究了在人工河水中暴露于铜的鲤鱼鳃部微环境的pH、碱度、粘液含量和铜形态分布.结果发现,鱼鳃pH平衡点为6.92,人工河水pH高于或低于此值时,鱼鳃微环境pH偏低或偏高.变化幅度约达-0.6至0.4 个pH单位.根据实测结果分别建立了计算人工河水和鱼鳃微环境碱度以及鱼鳃粘液分泌量随暴露铜含量和pH变化的定量模型.化学平衡计算结果说明,在pH6至9范围内,人工河水中优势态铜从游离态铜过渡到羟基络合态铜.由于粘液和pH差异的影响,鱼鳃微环境中生物有效态铜含量显著低于人工河水.这样的差别在酸性条件下尤为显著.     

CU2#重金属离子捕集剂去除废水中Cu2+的研究

研究了CU2#重金属离子捕集剂处理含铜废水的效果,结果表明:在pH1-14范围内,搅拌时间为5min,不加絮凝剂时,CU2#重金属离子捕集剂对含铜废水处理后,其上清液中铜含量可低于0.3mg·l-1,对铜的去除率达到99.7%,一次性处理后的含铜废水即达到国家排放标准.另外,用CU2#重金属离子捕集剂对EDTA络合铜离子的处理效果进行了初步探讨.     

根瘤菌S2对离子态和酒石酸络合态铜的吸附行为

探究根瘤菌S2的吸附动力学和热力学行为以及根据不同投菌量和pH的影响分析其对于Cu~(2+)及酒石酸络合铜的吸附性能;结合对吸附前后上清液及菌体进行EEM、FTIR、XRD以及XPS分析解释菌株吸附机理.结果表明,菌株吸附2 mg·L~(-1) Cu~(2+)及酒石酸络合铜均可分为快速吸附和慢速平衡阶段,12 h后基本达到平衡,吸附率达97%以上;温度的升高会导致吸附量增加.最适投菌量约为0.6 g·L~(-1) wet cells;菌株吸附Cu~(2+)的最适pH值为6,而当pH值小于10时菌株对于酒石酸络合铜的吸附几乎不受影响.在吸附过程中,溶解性微生物产物(SMP)、细胞壁上的还原和官能团络合机制均发挥关键作用,吸附铜离子过程中SMP的作用更明显,而细胞壁在络合铜的吸附过程中的作用较大,其破络效率决定于细菌活性.     

LIX984对铜离子的络合萃取

研究了铜离子在水相和油相(LIX984煤油溶液)之间的分配行为,考察操作参数对分配比的影响,分析计算该络合萃取过程的平衡常数.结果表明:载体LIX984对铜离子的萃取能力强、速度快,1min基本上达到萃取平衡;分配比随着萃取温度、油相载体初始浓度、水相初始pH值的增大而增大,而随着水相初始铜离子浓度的增大而下降;该络合萃取过程的平衡常数在30℃的值为7.6.     

络合态金属铜在大型水蚤(Daphnia magna)体内的生物积累及生物毒性

以人工稀释水作为背景水样,通过实验室暴露和化学平衡软件的辅助分析,研究了4种有机络合剂(草酸、酒石酸、EDTA和腐殖酸)对大型水蚤(Daphniamagna)体内铜的生物积累(BBD)以及生物毒性的影响.结果表明,有机络合剂的存在降低了大型水蚤体内生物积累量和金属硫蛋白(MT)含量,明显降低了水体中金属Cu的毒性,4种不同有机络合剂所产生的效果大体相同;有机络合态的铜也能为大型水蚤所吸收和利用,在相同浓度条件下大型水蚤对腐殖酸络合态铜的利用大于EDTA络合态铜.     

流式细胞术在铜对藻类生态毒理研究中的应用

用流式细胞术研究了铜对铜绿微囊藻的毒性作用 ,结果表明 ,一定浓度的铜对藻类的生长具有抑制作用 ,而且这种抑制作用随着铜浓度的增加而增加 ,96h的EC50 为 82 86μg·l- 1 ,当铜浓度为 1 0 1 2 5 μg·l- 1 时 ,藻细胞的生长几乎完全受到抑制 .流式细胞仪检测结果可以说明铜对藻类群体作用的过程 ,即铜并不是同时对所有的藻细胞产生抑制作用 .低浓度时只是对部分细胞产生抑制 ,随着铜浓度的升高 ,受到抑制的细胞也越多 ,当达到最高浓度时 ,几乎所有细胞的生长都受到抑制 .     

腐殖酸络合态铜对鱼的生物有效性

采虹方头鱼和阳离子树脂半透膜囊在添加和未添加腐殖酸的铜溶液中的暴露实验显示,树脂半透膜囊和鱼对游离铜的吸收与体系游离铜浓度均成线性关系。实测数据表明,腐殖酸能够抑制鱼鳃对铜的吸收;进一步的计算结果显示,腐殖酸络合态铜仍可以被鱼鳃所吸收。在相同的浓度条件下,鱼鳃对络合态铜的吸收率远低于对游离态铜的吸收率。     

蓝藻水华优势藻高效防控铜制剂的筛选

在对比络合铜、有机铜和无机铜3类5种典型铜制剂对蓝藻水华优势藻--铜绿微囊藻(Microcystis aeruginosa)和2种非靶标藻种--普通小球藻(Chlorella vulgaris)和斜生栅藻(Scenedesmus obliquus)的96 h生长抑制效果的基础上,进一步开展了3类铜制剂抑制铜绿微囊藻生长的15 d延长效应研究.试验结果表明,质量分数为25%的络氨铜水剂、30%琥胶肥酸铜可湿性粉剂和20%乙酸铜可湿性粉剂对蓝藻水华优势种有较好的生长抑制效果,其对初始密度为2×105～4×105mL-1铜绿微囊藻的96 h半抑制浓度(以下均以有效成分的质量计)分别为0.03、0.06和0.05 mg·L-1,且初始藻密度对抑藻效果并无明显影响.试验质量浓度为0.25 mg·L-1的25%络氨铜水剂、0.30 mg·L-1的30%琥胶肥酸铜可湿性粉剂或0.20 mg·L-1的20%乙酸铜可湿性粉剂均能抑制铜绿微囊藻增长,且在0～15 d内都不会出现藻细胞再次复苏和增长.此外,由于铜制剂对铜绿微囊藻的96 h半抑制浓度远低于其对普通小球藻和斜生栅藻的96 h半抑制浓度,因此可在有效控制靶标藻种的同时不对非靶标藻种的生长造成严重威胁.络氨铜、琥胶肥酸铜、乙酸铜有望被开发成为高效、绿色的蓝藻水华控制剂.     

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.