对我国生态系统服务研究局限性的思考及建议

自1997年生态系统服务的概念引入我国以来，我国学术界关于生态系统服务的研究呈现指数水平上升，但是研究的内容局限于不同区域和不同类型生态系统服务的价值化评估。评估结果的科学性和现实有效性受到质疑。本文结合我国目前的实际需求，我国生态系统服务研究的误区以及对千年生态系统评估（MA）研究成果的思考，认为目前和日后生态系统服务研究可以加强如下几个方面的研究：一是生态系统服务对人类福祉贡献的研究；二是生态系统服务功能退化现状的研究：三是生态系统服务退化原因和对策的研究。以丰富爱国生态系统服务研究的内窑。并为生态系统服务价值评估研究提供基础和补充。     

Cylinder cyclone (LARCODEMS) density media separation of plastic wastes

Cylindrical cyclone media separators using a suspended calcite separation media simulating industrial scale operations are demonstrated to effectively separate a wide variety of forms and a greater range of particle sizes of plastics by density than presently recycled. Purities of plastic products and recoveries obtained from mixed plastic wastes are comparable to those reported for established separations. Products of ≈100% purity with recoveries of >99% were obtained for high density fractions and >98% purities and recoveries for the low density fractions. Cyclonic centrifugal forces and/or the fine particle size of the separation media appear to minimize hydroscopic and particle shape effects.A mathematical model is proposed for defining plastic waste feed rates and treatable particle size ranges for the LARCODEMS media separator.Waste plastic separations yielded Ecart probable (Ep) values ?0.024 for a water only separation media. The Ep for 1.1 g cm^?3 separation medias was <0.032 with minimal to no variation in values for 1–8 mm particle sizes. Variation in the quality of separations is shown to be minimal with <72 μm, <45 μm and <2 μm media particle sizes. Media density offset created varied according to particle size.     

Frog call intensities and sound propagation in the South American temperate forest region

Sound pressure levels and the spectral structure of the advertisement calls of five species of frogs from the South American temperate austral forest were analyzed. Males of Eupsophus emiliopugini, Batrachyla antartandica and B. leptopus call from the ground in bogs, while males of Hylorina sylvatica and Pleurodema thaul call from the water surface in marshes. Calling males of the species from bogs and marshes spaced at average distances that were shorter and longer than 2 m, respectively. The properties of these habitats for sound propagation were evaluated by broadcasting pure tones, broadband noise and tape-recorded advertisement calls of the three species from bogs and of H. sylvatica. Excess attenuation and spectral degradation were higher for calls broadcast in bogs than in the marsh. The calls of B.␣antartandica and B. leptopus, with dominant frequencies of about 2 kHz, were more affected than those of E.␣emiliopugini and H. sylvatica, with dominant frequencies below 1.5 kHz. These results show the lack of an optimal relationship between properties of habitats for sound transmission and the spectral structure of these anuran calls. Body size imposes an important constraint on call spectra and propagation, which frogs counteract by distribution patterns and auditory capabilities. Received: 18 April 1997 / Accepted after revision: 15 February 1998     

Prenatal diagnosis of Mohr syndrome by ultrasonography

A case of prenatal diagnosis of Mohr syndrome is presented. The ultrasound examination was indicated by the previous birth of an affected brother. The need for genetic counselling is stressed, when polydactyly is observed accidentally at ultrasound examination during pregnancy.     

Movement patterns of the seastar Heliaster helianthus in central Chile: relationship with environmental conditions and prey availability

The rates and patterns of feeding and displacement of predators constitute two of the most important plastic behavioral responses that allow individuals to respond quickly to changes in abundance of their prey, predation risks and to rapid alterations in environmental conditions. In this study, we quantified seasonal and spatial variation in displacement (net changes in location in 12 or 24 h periods) and prey consumed of marked individuals of the keystone seastar Heliaster helianthus at six sites spanning 600 km along the coast of north-central Chile. We evaluated the hypotheses that: (1) at sites with low availability (cover) of the main prey, the mussel Perumytilus purpuratus, Heliaster displays larger displacements and consumes a greater proportion of other prey (e.g. mobile species) than at sites with high mussel cover, (2) daily displacements will be correlated with sea surface temperature (SST) and (3) increased wave action will reduce seastar daily displacement. Our results show that Heliaster displacement is higher at sites with lower availability of P. purpuratus; and at these sites, a larger proportion of Heliaster individuals are observed feeding, mostly on other prey (e.g. limpets), which could offset the higher costs associated with increased movement. In addition, wave forces affected the activity of Heliaster negatively. Contrary to our expectations, the daily displacements did not show any relationship with SST measured on the day or the previous days of the surveys, despite the fact that average displacement was generally higher in summer than in winter months. Future studies should examine Heliaster movement during single foraging excursions and determine whether these responses affect the growth and reproductive output of individuals. Such information is vital to understand how changes in prey abundance and environmental conditions alter the behavior and energy budget of this predator and its ability to control prey populations.     

Aluminium recovery vs. hydrogen production as resource recovery options for fine MSWI bottom ash fraction

Waste incineration bottom ash fine fraction contains a significant amount of aluminium, but previous works have shown that current recovery options based on standard on-step Eddy Current Separation (ECS) have limited efficiency. In this paper, we evaluated the improvement in the efficiency of ECS by using an additional step of crushing and sieving. The efficiency of metallic Al recovery was quantified by measuring hydrogen gas production. The ash samples were also tested for total aluminium content with X-ray fluorescence spectroscopy (XRF). As an alternative to material recovery, we also investigated the possibility to convert residual metallic Al into useful energy, promoting H₂ gas production by reacting metallic Al with water at high pH. The results show that the total aluminium concentration in the <4 mm bottom ash fraction is on average 8% of the weight of the dry ash, with less than 15% of it being present in the metallic form. Of this latter, only 21% can be potentially recovered with ECS combined with crushing and sieving stages and subsequently recycled. For hydrogen production, using 10 M NaOH at 1 L/S ratio results in the release of 6–11 l of H₂ gas for each kilogram of fine dry ash, equivalent to an energy potential of 118 kJ.     

Anaerobic degradation of naphthalene in a fluvial aquifer: a radiotracer study

A radiotracer study was conducted in a creosote-contaminated aquifer beneath the Fraser River, British Columbia Canada to investigate the in situ degradation of naphthalene. The groundwater is anaerobic, with abundant methane, ferrous iron and carbon dioxide. This study followed earlier work at the site where the contaminant distribution could only be explained by invoking a mass loss through degradation, even though extensive field and laboratory microcosm studies closer to the source zone onshore could not confirm degradation. Accordingly, 14C-naphthalene was injected into the aquifer offshore, further from the source zone where modeling suggested degradation was occurring. During the 230-day monitoring period, 14CO2 was detected, confirming the degradation of the radio-labeled naphthalene tracer. A zero-order degradation rate of naphthalene of 5 microg/L-day was estimated based on the decrease in 14C-naphthalene concentration with time. While the degradation pathway could not be determined from the radiotracer study alone, the geochemistry of the site suggests that either iron reduction or methanogenesis is the terminal electron accepting processes responsible for naphthalene oxidation.     

Derivation of a household-level vulnerability index for empirically testing measures of adaptive capacity and vulnerability

Recent studies have projected significant climate change impacts in Africa. In order to understand what this means in terms of human well-being at local level, we need to understand how households can cope and adapt. This need has led many authors to argue for approaches to adaptation that are based on vulnerability analysis. Vulnerability is one of the key terms in the climate change literature, but little progress has been made in the field of its quantification. Typically, indicators are combined according to a weighing scheme, with the identification of indicators and the weighing schemes based on expert judgment rather than empirical evidence. In addition, most quantitative assessments are applied to countries or other administrative units, whereas managing climate risk has traditionally been the responsibility of households. We therefore focus on the adaptive capacity of households. We analyze the coping strategies and vulnerability to climatic stresses of agro-pastoralists in Mozambique and test the validity of a number of commonly used vulnerability indicators. We derive a household-level vulnerability index based on survey data. We find that only 9 out of 26 indicators tested exhibit a statistically significant relationship with households’ vulnerability. In total, they explain about one-third of the variation in vulnerability between households, confirming the need for more research on underlying determinants and processes of vulnerability. With inclusion of local knowledge, our study findings can be used for local targeting, priority setting and resource allocation. Complemented with studies analyzing climate change impacts and findings from country-level adaptive capacity studies, governmental policy can be informed.