Book reviews

The Impact of English Towns P. J. Corfield

Oxford Paperbacks. O.U.P. 1982, 206 pp, £3.95 Bibliography, Maps, Graphs and Tables

Change in the City Centre

D. Sim

Gower, Aldershot 1982, £11.50, 124 pp.     

Insect mandibles—comparative mechanical properties and links with metal incorporation

A number of arthropod taxa contain metals in their mandibles (jaws), such as zinc, manganese, iron, and calcium. The occurrence of zinc and its co-located halogen chlorine have been studied in relation to the mechanical properties and shown to be linked in a direct fashion with increasing concentration. Hardness along with elastic modulus (stiffness) has also been linked to zinc and halogen concentration in some marine polychaete worms. The metal appears to be incorporated within the biological matrix, possibly bonding with proteins. However, the comparative advantage of metal inclusion has not been tested. It is possible that without metals, alternative mechanisms are used to achieve hardness of equal value in similar 'tools' such as mandibles. This question has direct bearing on the significance of metal hardening. In the present article, we compare across mandibles from six termite species, including samples with major zinc concentration, minor manganese, and no metals. Nanoindentation, electron microscopy, and electron microanalysis are used to assess metal concentration, form, and mechanical properties. The data demonstrate that termite mandibles lacking metals when fully developed have lower values for hardness and elastic modulus. Zinc is linked to a relative 20% increase in hardness when compared with mandibles devoid of metals. The similar transition metal, manganese, found in minor concentrations, is not linked to any significant increase in these mechanical properties. This raises the question of the function of manganese, which is as commonly found in insect mandibles as zinc and often located in the same mandibles.     

Pilot-scale studies on the effect of bromine addition on the emissions of chlorinated organic combustion by-products

The addition of brominated organic compounds to the feed of a pilot-scale incinerator burning chlorinated waste has been found previously, under some circumstances, to enhance emissions of volatile and semivolatile organic chlorinated products of incomplete combustion (PICs) including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs). This phenomenon appears to be sensitive to temperature and combustion conditions. This paper reports on a study to evaluate the emissions of organic combustion by-products while varying amounts of bromine (Br) and chlorine (Cl) are being fed into a pilot-scale incinerator burning surrogate waste materials. The surrogate waste was fed at a constant molar halogen input rate, with varying Br/Cl molar ratios. In these tests, an approximately 30% decrease in the total PCDD/F concentrations due to the addition of Br was observed. This decrease appears to be a decrease only in the chlorinated dioxin and furan species; other halogenated dioxins and furans were formed instead. PCDD/F homologue distribution shifted towards the higher chlorinated species. Perhalogenated or nearly perhalogenated mixed bromo-chloro furans were also observed in quantities that could potentially account for the observed decrease in PCDDs/Fs. This research illustrates the need for careful trial burn planning if Br will be present in the facility's feed-stock during normal operation.     

Systematics of radon at the Wairakei geothermal region, New Zealand

222Rn and 220Rn in geothermal steam at Wairakei, NZ, range from 11 to 19, 500 Bq kg-1, and 25 to 16, 700 Bq kg-1, respectively, but do not cause toxic concentrations in air. The wide ranges are mainly due to differences in different physical conditions underground (e.g. thin silica diffusion barriers), not geochemical differences. Groundwater Rn from outside the area probably plays only a minor role. 210Po was found present in non-toxic levels in the steam. Historical records showed little change in Rn concentration over several decades, therefore potentially hazardous concentrations might be predicted from early exploration. 220Rn concentrations at Wairakei should decrease as the field becomes steam-dominated. Rock surfaces were variably leached or enriched with U, Th, Ra and 210Pb, providing a possible model for deposition in cooler regions near the field. Estimates of 222Rn permeability ranged from 2 to 77% of the maximum possible, with a median of 13%.     

Agronomic Water Mass Balance vs. Well Measurement for Assessing Ogallala Aquifer Depletion in the Texas Panhandle

The Ogallala Aquifer is depleting faster than it is being replenished. Interpretation of well data suggests that the water table in some counties is not declining, or not as much as might be expected in view of the amount of land being irrigated. As the Ogallala Aquifer in the Texas Panhandle receives almost no recharge, a possible explanation is that the current method of using well data for estimating the quantity of water remaining in the aquifer is underestimating water in storage. This study used an agronomic water mass balance approach to estimate how much water has been used for irrigation compared to amounts estimated by well data. The major finding was in counties where irrigation well capacities have declined significantly but irrigation is continuing, there is likely more water in storage than presently estimated, but the amounts of water being used for irrigation in those counties are greater than estimated changes of water in storage. The proposed hypothesis for this difference is there are mounds of water between wells that are not being accounted for and data are presented and discussed to support this conjecture.     

2种杀菌制剂对微生物和大型无脊椎动物降解落叶的影响

水生真菌对于河流中的落叶降解这一重要的生态系统服务有着重要的作用。然而,杀真菌剂对于参与落叶降解的水生真菌和大型无脊椎动物的影响却鲜有了解。本实验将美国红枫（Acer rubrum）的叶片在河流中进行处理（处理组）以获得微生物（细菌与真菌）,或是在自来水下进行淋洗（未处理组）以模拟杀真菌剂可能带来的微生物生物量减少的情况。将处理组叶片分别置于绿钩虾属动物Hyalella azteca（端足类动物,在暴露开始时7日龄,是一种落叶分解物种）存在或不存在的环境中,在23 ℃条件下暴露于复合杀真菌剂QUILT（嘧菌酯和丙环唑）或是PRISTINE（啶酰菌胺和唑菌胺酯）培养14天。QUILT（~ 0.3 μg?L^-1, 1.8 μg?L^-1, 8 μg?L^-1）有加速端足类动物分解落叶的趋势（不显著）,却没有促进端足类动物本身生物量的同时增长,表明端足类动物对于落叶消费量的上升应该主要由于落叶营养成分的减少。PRISTINE（~ 33 μg?L^-1）显著地抑制了端足类动物的生长,降低其生物量（P<0.05）,在未处理组中也观察到类似结果。PRISTINE对于端足类动物生长显著的抑制作用以及随QUILT浓度升高而加快的落叶降解的趋势表明受到杀真菌剂影响的河流中落叶降解这一过程很可能被改变。在河流生态系统相关的条件下,如温度的变化和与杀虫剂混合后脉冲式的暴露,杀真菌剂对于落叶降解的影响需要进一步的研究。
精选自Adria A. Elskus, Kelly L. Smalling, Michelle L. Hladik, Kathryn M. Kuivila. Effects of 2 fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2834–2844, November 2016. DOI: 10.1002/etc.3465
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3465/full
     

A review of ecological mitigation measures in UK environmental statements with respect to sustainable development

SUMMARY

The European and UK legislation on environmental assessment (EA), as well as requiring assessment of significant ecological effects, also requires development proponents to recommend mitigation measures for adverse impacts.

Drawing on a review of proposed ecological mitigation measures in 194 environmental statements (ES) for UK development proposals, this paper highlights problems with the current legislation in ensuring that ecological impacts are mitigated effectively, with a view to sustainable development.

The review reveals confusion about the extent to which ecological mitigation is required. First, there is no objective basis for deciding which potentially adverse impacts should be mitigated. Proposed mitigation measures do not always relate directly to the ecological impacts identified in ES and there is a high risk of residual adverse effects. Second, there is no generally accepted method for evaluating the effectiveness of proposed mitigation measures, despite a clear recommendation from the UK's Department of the Environment (DOE, 1989) that an ‘assessment of the likely effectiveness’ of mitigation measures should be included in ES. Methods which can be used to evaluate the likely feasibility, costs and redistributional effects of ecological mitigation measures in EA are needed. Some of the factors which should be taken into account are considered in this paper.     

Microbial community phylogenetic and trait diversity declines with depth in a marine oxygen minimum zone

Oxygen minimum zones (OMZs) are natural physical features of the world's oceans. They create steep physiochemical gradients in the water column, which most notably include a dramatic draw down in oxygen concentrations over small vertical distances (<100 m). Microbial communities within OMZs play central roles in ocean and global biogeochemical cycles, yet we still lack a fundamental understanding of how microbial biodiversity is distributed across OMZs. Here, we used metagenomic sequencing to investigate microbial diversity across a vertical gradient in the water column during three seasons in the Eastern Tropical South Pacific (ETSP) OMZ. Based on analysis of small subunit ribosomal RNA (SSU rRNA) gene fragments, we found that both taxonomic and phylogenetic diversity declined steeply along the transition from oxygen-rich surface water to the permanent OMZ. We observed similar declines in the diversity of protein-coding gene categories, suggesting a decrease in functional (trait) diversity with depth. Metrics of functional and trait dispersion indicated that microbial communities are phylogenetically and functionally more overdispersed in oxic waters, but clustered within the OMZ. These dispersion patterns suggest that community assembly drivers (e.g., competition, environmental filtering) vary strikingly across the oxygen gradient. To understand the generality of our findings, we compared OMZ results to two marine depth gradients in subtropical oligotrophic sites and found that the oligotrophic sites did not display similar patterns, likely reflecting unique features found in the OMZ. Finally, we discuss how our results may relate to niche theory, diversity-energy relationships and stress gradients.     

Assessing the status and trend of bat populations across broad geographic regions with dynamic distribution models

Bats face unprecedented threats from habitat loss, climate change, disease, and wind power development, and populations of many species are in decline. A better ability to quantify bat population status and trend is urgently needed in order to develop effective conservation strategies. We used a Bayesian autoregressive approach to develop dynamic distribution models for Myotis lucifugus, the little brown bat, across a large portion of northwestern USA, using a four-year detection history matrix obtained from a regional monitoring program. This widespread and abundant species has experienced precipitous local population declines in northeastern USA resulting from the novel disease white-nose syndrome, and is facing likely range-wide declines. Our models were temporally dynamic and accounted for imperfect detection. Drawing on species-energy theory, we included measures of net primary productivity (NPP) and forest cover in models, predicting that M. lucifugus occurrence probabilities would covary positively along those gradients. Despite its common status, M. lucifugus was only detected during -50% of the surveys in occupied sample units. The overall naive estimate for the proportion of the study region occupied by the species was 0.69, but after accounting for imperfect detection, this increased to -0.90. Our models provide evidence of an association between NPP and forest cover and M. lucifugus distribution, with implications for the projected effects of accelerated climate change in the region, which include net aridification as snowpack and stream flows decline. Annual turnover, the probability that an occupied sample unit was a newly occupied one, was estimated to be low (-0.04-0.14), resulting in flat trend estimated with relatively high precision (SD = 0.04). We mapped the variation in predicted occurrence probabilities and corresponding prediction uncertainty along the productivity gradient. Our results provide a much needed baseline against which future anticipated declines in M. lucifugus occurrence can be measured. The dynamic distribution modeling approach has broad applicability to regional bat monitoring efforts now underway in several countries and we suggest ways to improve and expand our grid-based monitoring program to gain robust insights into bat population status and trend across large portions of North America.