酸沉降和大气污染对华南典型森林生态系统生物量的影响

调查酸沉降和大气污染对华南典型森林生态系统植物生物量的影响。结果发现,环境污染对树木的生长以及森林生物量影响较大。采用树干解析方法研究发现,不管是尾叶桉还是马尾松其树高、胸径和材积连年生长量基本趋势是污染地区样地比清洁区样地低。尾叶桉和马尾松林分中的生物量也是污染区样地比清洁区样地低。污染区样地中尾叶桉和马尾松林分总生物量分别为66.89t·hm-2和77.56t·hm-2,仅分别为清洁区的78.89%和94.49%。环境污染均促进这两个树种根系的生长,而抑制其干材的生长。尾叶桉和马尾松根系生物量占林木层生物量比例:污染区样地分别为65.16%和15.08%;清洁区分别为40.50%和14.48%。此两个树种干材生物量占林木层生物量比例:污染区样地分别为19.87%和57.71%;清洁区分别为38.15%和70.33%。本研究结果将为华南地区森林生态系统的保护提供科学依据。     

High Spatial and Temporal Variability of Dry Deposition in a Coastal Region

A real meteorological situation characterized by strong spatial and temporal variability of the meteorological fields in a coastal region of eastern Denmark is examined in view of the transport of a passive tracer and dry deposition. Model simulations using a full mesoscale NWP model (COAMPS^TM) at different horizontal resolutions are performed. A realistic simulation showed that the differences in the amount of dry deposited matter can reach one order of magnitude and larger, during the period of one afternoon, depending on the model horizontal resolution. In addition, the results of an idealized experiment with straight coastline indicate that the horizontal model resolution alone is responsible for most of the differences. This study confirms the importance of high spatial and temporal resolution modelling for environmental applications.     

酸沉降下加速土壤酸化的影响因素

酸沉降对土壤和水域的酸化影响是土壤环境化学研究前沿的热点问题之一。酸沉降的化学组成对酸性土壤的进一步酸化起着催化剂的作用。在酸雨影响下,SO42-、NO-3、有机阴离子是加速土壤酸化和盐基淋溶损失的主要阴离子,外源H+的进入会加速铝离子水解。自然因素与人为因素导致土壤酸化的实际酸化速率差异表明:HCO3-、RCOO-在土壤剖面中的淋失状况可反映自然土壤的酸化速率,而SO42-和NO-3淋溶产生的质子负荷揭示土壤受人为因素影响的酸化速率。通过计算酸沉降的主要化学成分进入土壤前后的质子负荷平衡,与酸中和容量(ANC)相结合,反映酸沉降加速土壤酸化的进程。     

锅炉大气污染物测试

为贯彻国家新标准“锅炉大气污染物排放标准”（ＧＢ５４６８－９１），本文探讨了准确测算烟气流速，干烟气平均分子量等关于锅炉烟尘和ＳＯ２排放浓度测试的技术问题，对不易测试的参数提供经验估算法。     

秸秆干发酵沼气增产研究

研究了复合菌剂预处理秸秆和添加沼气发酵促进剂对秸秆干发酵的影响.结果表明,秸秆经菌剂预处理后的产气量比不加菌剂预处理(对照)提高29.54%;在菌剂预处理过的秸秆中加入促进剂,其产气量比对照提高35.28%,比单纯菌剂预处理提高4.43%.另外,菌剂预处理过的秸秆的TOC降解率和纤维素降解率分别比对照高136.32%和47.68%;秸秆经菌剂预处理后再添加促进剂的TOC降解率、纤维素降解率分别比对照高169.58%和49.62%,比单纯菌剂预处理高14.07%和3.36%.图2表1参8     

Mother’s choice of the oviposition site: balancing risk of egg parasitism and need of food supply for the progeny with an infochemical shelter?

Summary. Oviposition site selection of herbivorous insects depends primarily on host plant presence which is essential for offspring survival. However, parasitoids can exploit host plant cues for host location. In this study, we hypothesised that herbivores can solve this dilemma by ovipositing within high plant diversity. A diverse plant species composition might represent an ‘infochemical shelter’, as a potentially complex volatile blend can negatively affect the host location ability of parasitoids. We examined this exemplarily for the egg-laying response of the generalist leaf beetle, Galeruca tanaceti, in relation to (1) host plant availability and (2) plant species diversity in the field. Further, we investigated the effect of odours from mixed plant species compositions on (3) leaf beetle oviposition site selection and on (4) the orientation of its specialised egg parasitoid, Oomyzus galerucivorus. In the field, egg clutch occurrence was positively related to the presence and quantity of two major host plants, Achillea millefolium (yarrow) and Centaurea jacea, and to the number of herbaceous plant species. In two-choice bioassays, female beetles oviposited more frequently on sites surrounded by an odour blend from a diverse plant species composition (including yarrow) than on sites with a pure grass odour blend. In the presence of yarrow odour and an odour blend from a diverse plant mixture (including yarrow) no difference in the oviposition response was recorded. Experienced parasitoid females were attracted to yarrow odours, but showed no response when yarrow odours were offered simultaneously with odours of a non-host plant. In conclusion, it could be shown in laboratory bioassays that the parasitoid responds only to pure host plant odours but not to complex odour blends. In contrast, the herbivore prefers to oviposit within diverse vegetation in the field and in the laboratory. However, the laboratory results also point to a priority of host plant availability over the selection of a potential ‘infochemical shelter’ for oviposition due to high plant diversity.     

Integrating pattern-based modelling and political ecology in land-use change research: the case of Mexican dry tropics

ABSTRACT

Agricultural and extractive frontiers experiment rapid landscape transformation. Land-Use Sciences and Political Ecology are complementary approaches for analysing how landscape transformations are related to biophysical conditions, and socioeconomic, cultural and political processes developed at global, national and local scales. This study examines such relationships in a long-standing agrarian and resource frontier in southern Mexico for the 1986–2015 period. We combine insights from: (1) a quantitative land use/land cover change pattern-based model, involving a weights of evidence and cellular automata simulations, and (2) a qualitative content analysis of literature and of local actors’ perspectives. Two grand frontier processes have developed in this region: NAFTA-related agrarian transition toward intensification and the establishment of wind farms. Both were triggered by global forces and new forms of land and resources use, but mediated by national-to-local ecological, socioeconomic and political processes, producing particular landscape transformations.     

Pollution survey of polycyclic aromatic hydrocarbons in surface water of Hangzhou, China

The concentrations of 10 polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured for five times (July and November 1999–2002) in four water bodies of Hangzhou, China. To investigate possible sources of PAH contamination, sediments, soils, runoff water and atmospheric particles of the region were also analyzed for their PAH contents. The maximum levels of PAHs in the water bodies (34.4–67.7 μg/l) were found in July, while significantly lower PAH concentrations (4.7–15.3 μg/l) were measured in November. The contamination is substantial and it may have resulted in acute toxic effects on aquatic organisms. The measured PAH concentrations in sediments and soils (224–4222 ng/g), runoff water (8.3 μg/l) and air particles (2.3 μg/m³) are discussed in relation to concentrations and patterns found in the surface water bodies. Comparison of PAH levels in sediments and soils led to the conclusion that the erosion of soil material does not contribute significantly to the contamination of sediments. The atmospheric PAH deposition to water bodies in the city area of Hangzhou was estimated to be 530 tons/a, while the contribution of surface runoff water was estimated to be 30.7 tons/a. The ratios of selected PAH were then used to illuminate the possible origin of PAHs in the examined samples (petrogenic, pyrogenic).     

Spatial distribution and source identification of wet deposition at remote EANET sites in Japan

Wet deposition of major ions was discussed from the viewpoint of its potential sources for six remote EANET sites in Japan (Rishiri, Happo, Oki, Ogasawara, Yusuhara, and Hedo) having sufficiently high data completeness during 2000–2004. The annual deposition for each site ranged from 12.1 to 46.6 meq m⁻² yr⁻¹ for nss-SO₄²⁻, from 5.0 to 21.9 meq m⁻² yr⁻¹ for NO₃⁻. The ranges of annual deposition of the two ions for the sites were lower than those for urban and rural sites in Japanese Acid Deposition Survey by Ministry of the Environment, Japan, and higher than those for global remote marine sites. Factor analysis was performed on log-transformed daily wet deposition of major ions for each site. The obtained two factors were interpreted as (1) acid and soil source (or acid source for some sites), and (2) sea-salt source for all the sites. This indicates that wet deposition of ions over the remote areas in Japan has a similar structure in terms of types of sources. Factor scores of acid and soil source were relatively high during Kosa (Asian dust) events in spring in western Japan. Back-trajectories for high-deposition episodes of acid and soil source (or acid source) for the remote sites showed that episodic air masses frequently came from the northeastern area of Asian Continent in spring and winter, and from central China in summer and autumn. This indicates a large contribution of continental emissions to wet deposition of ions over the remote areas in Japan.     

Regional pattern of mercury wet deposition in Beijing

ＩｎｔｒｏｄｕｃｔｉｏｎＲｅｃｅｎｔｆｉｎｄｉｎｇｓｆｒｏｍｍｅｒｃｕｒｙｒｅｓｅａｒｃｈｉｎｄｉｃａｔｅｔｈａｔｔｈｅｍａｊｏｒｓｏｕｒｃｅｔｏｌａｋｅｓｉｓａｔｍｏｓｐｈｅｒｉｃｄｅｐｏｓｉｔｉｏｎ(Ｓｏｒｅｎｓｅｎ ,1990 ;Ｇｌａｓｓ,1990 ) ,ａｎｄｔｈａｔｓｉｇｎｉｆｉｃａｎｔｓｏｕｒｃｅｓｔｏｔｈｅａｔｍｏｓｐｈｅｒｅａｒｅｆｏｓｓｉｌｆｕｅｌｃｏｍｂｕｓｔｉｏｎａｎｄｉｎｃｉｎｅｒａｔｉｏｎｏｆｍｕｎｉｃｉｐａｌｓｏｌｉｄｗａｓｔｅａｎｄｓｌｕｄｇｅ(Ｇｌａｓｓ,1991;Ｗｈｉｔｅ ,1992 ;Ｃ…