沉积物磷的分级提取方法及提取相的共性分析

磷是湖泊营养状况的重要指标。文章综述了沉积物磷形态分级提取的经典方法,根据提取相的性质特点,将不同方法提取到的不同形态的磷综合归纳为几大类别,包括活性磷(Ⅰ)(可交换磷、松结态磷、不稳性磷及弱吸附性磷)、活性磷(Ⅱ)(铝结合态磷与铁结合态磷)、相对稳态磷和有机磷等,从而改善不同方法、不同研究对象在沉积物磷形态分析方面缺乏可比性的现状。     

镉敏感水稻突变体在镉胁迫下活性氧代谢的变化

从粳稻中花11为受体构建的经农杆菌介导的T-DNA插入水稻突变体库中获得了1个对镉敏感的突变体,野生型和突变体经Cd²⁺胁迫表型上有显著差异.结果表明:镉敏感水稻突变体地上部对Cd²⁺吸收与转运速率要快于野生型,膜脂过氧化程度更高;随Cd²⁺胁迫浓度的增加,O₂^·-和H₂O₂在叶片中的积累增加,诱导抗氧化代谢;敏感突变体叶片SOD的抗氧化胁迫能力是有限的,与野生型相比突变体叶片CAT受到更显著的抑制,可能是其对Cd²⁺胁迫更加敏感的生理原因.而叶片G-POD活性整体差异不显著.     

Effect of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction of NOx with C2H5OH

The influence of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction （SCR） of NOx with C2H5OH was investigated experimentally. The activity test results suggest that Ag-Pd/Al2O3 shows a small activity loss in the presence of SO2 when using C2H5OH as a reductant. In situ DRIFTS spectra show that the activity loss originates from the formation of surface sulphate species on the Ag-Pd/Al2O3. The surface sulphate species formation inhibits the formation of nitrate, whereas hardly changes the partial oxidation of C2H5OH. Compared with the NOx reduction by C3H6, an obvious suppression of the surface sulphate species formation was observed by DRIFTS experiment when using C2H5OH as a reductant. This phenomenon reveals the better catalytic performance and strong SO2 tolerance of Ag-Pd/Al2O3-C2H50H system.     

Economic Impacts of Zebra Mussels on Drinking Water Treatment and Electric Power Generation Facilities

Invasions of nonnative species such as zebra mussels can have both ecological and economic consequences. The economic impacts of zebra mussels have not been examined in detail since the mid-1990s. The purpose of this study was to quantify the annual and cumulative economic impact of zebra mussels on surface water-dependent drinking water treatment and electric power generation facilities (where previous research indicated the greatest impacts). The study time frame was from the first full year after discovery in North America (Lake St. Clair, 1989) to the present (2004); the study area was throughout the mussels’ North American range. A mail survey resulted in a response rate of 31% for electric power companies and 41% for drinking water treatment plants. Telephone interviews with a sample of nonrespondents assessed nonresponse bias; only one difference was found and adjusted for. Over one-third (37%) of surveyed facilities reported finding zebra mussels in the facility and almost half (45%) have initiated preventive measures to prevent zebra mussels from entering the facility operations. Almost all surveyed facilities (91%) with zebra mussels have used control or mitigation alternatives to remove or control zebra mussels. We estimated that 36% of surveyed facilities experienced an economic impact. Expanding the sample to the population of the study area, we estimated $267 million (BCa 95% CI = $161 million–$467 million) in total economic costs for electric generation and water treatment facilities through late 2004, since 1989. Annual costs were greater ($44,000/facility) during the early years of zebra mussel infestation than in recent years ($30,000). As a result of this and other factors, early predictions of the ultimate costs of the zebra mussel invasion may have been excessive.     

Efficacy of Control Measures for European Buckthorn (<Emphasis Type="Italic">Rhamnus cathartica</Emphasis> L.) in Saskatchewan

Introduced to Saskatchewan in the 1930s as a potential shelterbelt species, European buckthorn is now a prominent understory shrub in riparian woodland and shrub communities around Saskatoon. Locally, the Meewasin Valley Authority (MVA) is actively controlling buckthorn as part of its mandate to conserve natural heritage resources of the South Saskatchewan River Valley, with the goal of restoring the natural biodiversity of remnant patches of native vegetation. European buckthorn is normally dioecious, and MVA has chosen to treat only fruiting stems in an attempt to limit seed production. Two control techniques have been used. In one treatment, glyphosate was applied to stems after cutting; alternatively Garlon 4 Dow AgroSciences herbicide (active ingredient triclopyr) was applied as a chemical girdle directly to the stems using a streamline basal bark spray method. To date, more than 347,000 fruiting stems of buckthorn have been treated. Results indicate good initial progress in limiting seed production in dense buckthorn sites, but at a high cost. Although seed eradication is not a practical short-term goal for the Saskatoon buckthorn population, chemical girdling can substantially and strategically reduce seed and effectively limit spread. Field-tested strategies to reduce costs and improve efficiencies are discussed.     

Temperatures and Locations Used by Hibernating Bats,Including <Emphasis Type="Italic">Myotis sodalis</Emphasis> (Indiana Bat), in a Limestone Mine: Implications for Conservation and Management

Understanding temperatures used by hibernating bats will aid conservation and management efforts for many species. A limestone mine with 71 km of passages, used as a hibernaculum by approximately 30,000 bats, was visited four times during a 6-year period. The mine had been surveyed and mapped; therefore, bats could be precisely located and temperatures (T _s) of the entire hibernaculum ceiling accurately mapped. It was predicted that bats should hibernate between 5 and 10°C to (1) use temperatures that allow a near minimal metabolic rate, (2) maximize the duration of hibernation bouts, (3) avoid more frequent and prolonged arousal at higher temperatures, (4) avoid cold and freezing temperatures that require an increase in metabolism and a decrease in duration of hibernation bouts or that could cause death, and (5) balance benefits of a reduced metabolic rate and costs of metabolic depression. The distribution of each species was not random for location (P < 0.000) or T _s (P < 0.000). Myotis sodalis (Indiana bat) was most restricted in areas occupied, hibernating in thermally stable yet cold areas ( = 8.4 ± 1.7°C); 99% associated with cement block walls and sheltered alcoves, which perhaps dampened air movement and temperature fluctuations. Myotis lucifugus (little brown myotis) hibernated in colder, more variable areas ( = 7.2 ± 2.6°C). Myotis septentrionalis (northern myotis), Pipistrellus subflavus (eastern pipistrelle), and Eptesicus fuscus (big brown bat) typically hibernated in warm, thermally stable areas ( = 9.1 ± 0.2°C, = 9.6 ± 1.9°C, and = 9.5 ± 1.5°C, respectively). These data do not indicate that hibernacula for M. sodalis, an endangered species, should be manipulated to cool below 5°C.     

Capacity of Management Plans for Aquatic Invasive Species to Integrate Climate Change

Abstract:  The consequences of climate change will affect aquatic ecosystems, including aquatic invasive species (AIS) that are already affecting these ecosystems. Effects on AIS include range shifts and more frequent overwintering of species. These effects may create new challenges for AIS management. We examined available U.S. state AIS management plans to assess each program's capacity to adapt to climate-change effects. We scored the adaptive capacity of AIS management plans on the basis of whether they addressed potential impacts resulting from climate change; demonstrated a capacity to adapt to changing conditions; provided for monitoring strategies; provided for plan revisions; and described funding for implementation. Most plans did not mention climate change specifically, but some did acknowledge climatic boundaries of species and ecosystem sensitivities to changing conditions. Just under half the plans mentioned changing environmental conditions as a factor, most frequently as part of research activities. Activities associated with monitoring showed the highest capacity to include information on changing conditions, and future revisions to management plans are likely to be the easiest avenue through which to address climate-change effects on AIS management activities. Our results show that programs have the capacity to incorporate information about climate-change effects and that the adaptive-management framework may be an appropriate approach.     

Ecology of ground beetles in an industrial city

Specific ecological features of ground beetles inhabiting city parks and suburban areas were studied in the large industrial city of Nizhnii Tagil (Sverdlovsk oblast). Carabid cenoses of city parks retained considerable species diversity but proved to be strongly dominated by a limited number of species. An analysis of their state before and after recreational impact revealed changes in the species composition of communities, the set of dominant species, the degrees of their dominance, and the ratio between classes of life forms. The results show that the stronger the recreational impact, the more significant the decrease in the species diversity of the carabid community.     

Threatened Species and the Potential Loss of Phylogenetic Diversity: Conservation Scenarios Based on Estimated Extinction Probabilities and Phylogenetic Risk Analysis

Abstract: New species conservation strategies, including the EDGE of Existence (EDGE) program, have expanded threatened species assessments by integrating information about species' phylogenetic distinctiveness. Distinctiveness has been measured through simple scores that assign shared credit among species for evolutionary heritage represented by the deeper phylogenetic branches. A species with a high score combined with a high extinction probability receives high priority for conservation efforts. Simple hypothetical scenarios for phylogenetic trees and extinction probabilities demonstrate how such scoring approaches can provide inefficient priorities for conservation. An existing probabilistic framework derived from the phylogenetic diversity measure (PD) properly captures the idea of shared responsibility for the persistence of evolutionary history. It avoids static scores, takes into account the status of close relatives through their extinction probabilities, and allows for the necessary updating of priorities in light of changes in species threat status. A hypothetical phylogenetic tree illustrates how changes in extinction probabilities of one or more species translate into changes in expected PD. The probabilistic PD framework provided a range of strategies that moved beyond expected PD to better consider worst‐case PD losses. In another example, risk aversion gave higher priority to a conservation program that provided a smaller, but less risky, gain in expected PD. The EDGE program could continue to promote a list of top species conservation priorities through application of probabilistic PD and simple estimates of current extinction probability. The list might be a dynamic one, with all the priority scores updated as extinction probabilities change. Results of recent studies suggest that estimation of extinction probabilities derived from the red list criteria linked to changes in species range sizes may provide estimated probabilities for many different species. Probabilistic PD provides a framework for single‐species assessment that is well‐integrated with a broader measurement of impacts on PD owing to climate change and other factors.