Spontaneous revegetation vs. forestry reclamation in post-mining sand pits

Vegetation development of sites restored by two different methods, spontaneous revegetation and forestry reclamation, was compared in four sand pit mining complexes located in the southern part of the Czech Republic, central Europe. The space-for-time substitution method was applied to collect vegetation records in 13 differently aged and sufficiently large sites with known history. The restoration method, age (time since site abandonment/reclamation), groundwater table, slope, and aspect in all sampled plots were recorded in addition to the visual estimation of percentage cover of all present vascular plant species. Multivariate methods and GLM were used for the data elaboration. Restoration method was the major factor influencing species pattern. Both spontaneously revegetated and forestry reclaimed sites developed towards forest on a comparable timescale. Although the sites did not significantly differ in species richness (160 species in spontaneously revegetated vs. 111 in forestry reclaimed sites), spontaneously revegetated sites tended to be more diverse with more species of conservation potential (10 Red List species in spontaneous sites vs. 4 Red List species in forestry reclaimed sites). These results support the use of spontaneous revegetation as an effective and low-cost method of sand pit restoration and may contribute to implementation of this method in practice.     

湿地生态系统碳汇与碳源过程的控制因子和临界条件

湿地生态系统由于其自身的结构组分特征,已成为地球表层系统中最为重要的碳汇。但是近年来对于湿地系统的不合理开发利用、降水减少等原因使其碳汇功能减弱,湿地的碳蓄积能力下降且有转变为碳源的趋势。文章从湿地生态系统的水份、植物类型、土壤厚度、微生物(底物、pH、温度、氧化还原条件)等方面总结了影响湿地碳汇/源过程的控制因子和临界交替条件。湿地水位的高低决定湿地的氧气环境,与甲烷产生量成正相关,但却与二氧化碳产生量有一定的负相关关系。湿地植物通过通气组织与根系分泌物等影响湿地碳的吸收与排放通量,湿地植株的高度、覆盖率等也是影响湿地作为碳汇与碳源的重要因素。不同深度土层由于其产甲烷菌、甲烷氧化菌等微生物活性不同导致各个土层碳吸收、排放通量的差异,通常浅层土壤中的CO2、CH4的产生率高于深层土壤。微生物的活跃程度直接影响到湿地碳的吸收与排放,影响活跃程度的因素包括湿地底物、pH、温度与氧化还原条件等。湿地底物浓度的增加会在一定程度上提高甲烷的产生率,中性或者是弱碱性环境是产甲烷菌的最适宜条件,在一定范围内温度越高,甲烷产生量越大,而温度对于二氧化碳的影响则是通过改变光合作用来实现。氧化还原电位与甲烷产生量成负相关关系,-...     

土壤微生物生物量及多样性测定方法评述

土壤微生物作为土壤中重要的分解者,在养分的循环与转化中起着重要的作用。另外,由于其与土壤理化性质相比,对外界环境的变化更为敏感,因此,土壤微生物性质常被用作表征土壤质量的灵敏性指标,而土壤微生物生物量与微生物多样性是土壤微生物学研究中应用最广泛的指标。土壤环境复杂,微生物种类丰富多样,需要合适的研究方法才能真正打开土壤系统这个黑箱,自19世纪60年代以后,土壤微生物学在研究方法上取得了重要的进展,本文综述了微生物生物量及多样性的概念及微生物生物量和多样性研究方法的发展状况,重点就已有应用比较多的研究方法如测定微生物生物量的熏蒸法,测定微生物多样性的平板计数法、Biolog微平板计数法、磷脂脂肪酸法及分子生物学等研究方法进行了详细介绍及优缺点分析。结合现有微生物生物量及多样性的测定方法,在未来的研究中,一方面应该引入更多的新技术,发展新方法,以期探索更多的未知微生物种群;其次应该根据实验要求,完善和改进现有研究方法,使其更为统一和准确;再者,在微生物数据的分析上应该探索和借鉴更多的分析方法和手段,从而更深入更全面的解读实验当中所得到的微生物的信息。     

Effects of El Niño/Southern Oscillation on the population dynamics of a Gari solida population (Bivalvia: Psammobiidae) from Bahía Independencia,Peru

Population dynamics of a Gari solida (Gray, 1828) population from Bahía Independencia, Peru (14°S) was studied between November 1989 and February 1995 (except for 1991) in order to investigate the effects of the climate phenomenon El Niño/Southern Oscillation (ENSO) which occurred in 1992/93. Results indicate that ENSO had negative effects on gonad production in 1992, when temperatures were very high, and positive effects in 1993, when temperatures were lower, but the warm period lasted longer than in 1992. Higher reproductive output in 1993 was achieved by several spawning events in addition to the normal pattern. Growth rate in 1990 was higher (K=0.495) than in 1993/94 (K=0.346). A possible explanation could be that more energy was allocated to reproduction, and thus less surplus energy remained for growth. The negative effect of ENSO on production in 1992 is indicated by the low P/B ratio (0.298); in all other years P/B was consistently higher (1990: 0.570; 1993: 0.597; 1994: 0.597). From 1990 to 1994 a reduction of mean annual biomass from 189.3 to 14.4 g ash-free dry weight m^-2 was also observed which may be related to fishery activities. The consistency of P/B ratio is best explained by the higher somatic production of the smaller individuals remaining after the larger individuals had been removed selectively by fishermen. Based on the results presented in this study and from the literature, a model is proposed depicting how ENSO may negatively affect bivalve populations. Two main factors are mentioned, increased temperature and reduction of assimilated energy.Contribution No. 991 of the Alfred-Wegener-Institut für Polar- und Meeresforschung, Germany     

Total cobalt determination in human blood and synovial fluid using inductively coupled plasma-mass spectrometry: method validation and evaluation of performance variables affecting metal hip implant patient samples

Inductively coupled plasma with mass spectrometric detection (ICP-MS) has been used for clinical analysis of cobalt (Co) due to its sensitivity and specificity; however, media-specific validation studies are lacking. This study provides data on performance variables affecting differences between selected analytical platforms (Perkin Elmer and Agilent), tissue sample preparation, storage, and interferences affecting measurements in whole blood, serum, and synovial fluid. The limits of detection (LOD) range from 0.2–0.5 µg/L in serum and synovial fluid, and 0.6–1.7 µg Co/L in whole blood. The Agilent platform with collision reaction cell is more sensitive, while the Perkin Elmer platform with dynamic reaction cell demonstrates more polyatomic interferences near the LOD for serum and whole blood. Split sample analysis showed good accuracy, precision, and reproducibility between serum Co measurements using acid digestion or detergent dilution preparations for persons with metal hip implants or following supplement intake. The results demonstrated reliability of the ICP-MS methodology across the two analytical platforms and between two commercial laboratories for Co concentrations above 5 µg Co/L, but digestion procedures and polyatomic interferences may affect measurements in some media at lower concentrations. These studies validate the described ICP-MS methodology for clinical purposes with precautions at low cobalt concentrations (<5 µg Co/L).     

Nanoparticles: Their potential toxicity,waste and environmental management

This literature review discusses specific issues related to handling of waste containing nanomaterials. The aims are (1) to highlight problems related to uncontrolled release of nanoparticles to the environment through waste disposal, and (2) to introduce the topics of nanowaste and nanotoxicology to the waste management community. Many nanoparticles used by industry contain heavy metals, thus toxicity and bioaccumulation of heavy metals contained in nanoparticles may become important environmental issues. Although bioavailability of heavy metals contained in nanoparticles can be lower than those present in soluble form, the toxicity resulting from their intrinsic nature (e.g. their size, shape or density) may be significant. An approach to the treatment of nanowaste requires understanding of all its properties – not only chemical, but also physical and biological. Progress in nanowaste management also requires studies of the environmental impact of the new materials. The authors believe Amara’s law is applicable to the impact of nanotechnologies, and society might overestimate the short-term effects of these technologies, while underestimating the long-term effects. It is necessary to have basic information from companies about the level and nature of nanomaterials produced or emitted and about the expectation of the life cycle time of nanoproducts as a basis to estimate the level of nanowaste in the future. Without knowing how companies plan to use and store recycled and nonrecycled nanomaterials, development of regulations is difficult. Tagging of nanoproducts is proposed as a means to facilitate separation and recovery of nanomaterials.     

Seasonal variations in the densities of fecal pellets produced by Oikopleura vanhoeffeni (C. Larvacea) and Calanus finmarchicus (C. Copepoda)

Two abundant macrozooplankters, Oikopleura vanhoeffeni (Lohmann) and Calanus finmarchicus (Gunnerus) were collected from the coastal waters off Newfoundland in different seasons during 1990–1991 and incubated in natural seawater to collect freshly egested, field produced, fecal pellets. The densities of fecal pellets from O. vanhoeffeni and C. finmarchicus were measured in an isosmotic density gradient. These are the first reported seasonal measurements of fecal pellet densities from two different types of macrozooplankters, O. vanhoeffeni, a larvacean, filter feeder and C. finmarchicus, a crustacean, suspension feeder. Pellet density ranges and medians were significantly different among seasons for both species, depending primarily on the type of phytoplankton ingested and its ability to be compacted. Winter O. vanhoeffeni and fall C. finmarchicus feces filled with nanoplankters and soft bodied organisms had less open space [packing index (% open area) = 3.5 and 4% for O. vanhoeffeni and C. finmarchicus, respectively] and were more dense (1.23 and 1.19 g cm^-3) than spring feces filled with diatoms (packing index = 15 and 23%, density = 1.13 and 1.11 gcm^-3). For copepods, these results contrast with previously published density values and with the predicted copepod fecal pellet density calculated, in the present study, using the conventional mass/volume relationship. Copepod spring and summer diatom-filled feces had a calculated density of 1.12 and 1.24 gcm^-3 vs a measured median density of 1.11 gcm^-3 for both spring and summer feces; the fall feces containing nanoplankters had a calculated density of 1.08 gcm^-3 vs a measured median density of 1.19 gcm^-3. Knowledge of the seasonal variations in fecal pellet densities is important for the development of flux models.     

China as a new shaper of international development: the environmental implications

The emergence of China as a global player challenges the pre-existing dominance of the OECD countries and will continue to be a crucial force for global change in coming decades. The implications of China’s rise will be most significant for low- and middle-income countries, but the outcomes will also affect China’s relations with traditional donors and the understanding of the process of development. While these issues are increasingly explored at the political and economic level, very little analysis is available for the environmental impacts that China has on low- and middle-income countries. It is well understood that China plays a major role in relation to climate change, energy use and natural resource use at the global level; however, the perspective of China’s environmental impacts on low- and middle-income countries is underexplored. This Special Issue, therefore, elaborates the rise of China from the environmental perspective and assesses the impacts of China’s rise on low- and middle-income countries for international research, policy and practice in the field of environment and development. The findings draw on insights relevant for energy, water, forestry and land issues in Asia, Africa and Latin America.