Two water quality monitoring strategies designed to sample hydrophobic organic contaminants have been applied and evaluated across an expected concentration gradient in PAHs in the Moreton region. Semipermeable membrane devices (SPMDs) that sequester contaminants via passive diffusion across a membrane were used to evaluate the concentration of PAHs at four and five sites in spring and summer 2001/2002, respectively. In addition, induction of hepatic cytochrome P4501, EROD activity, in yellowfin bream, Acanthopagrus australis, captured in the vicinity of SPMD sampling sites following deployment in summer was used as a biomarker of exposure to PAHs and related chemicals. SPMDs identified a clear and reproducible gradient in PAH contamination with levels increasing from east to west in Moreton Bay and upstream in the Brisbane River. The highest PAH concentrations expressed as B(a)P-toxicity equivalents (TEQs) were found in urban areas, which were also furthest upstream and experienced the least flushing. Cytochrome P4501 induction in A. australis was similar at all sites. The absence of clear trends in EROD activity may be attributable to factors not measured in this study or variable residency time of A. australis in contaminated areas. It is also possible that fish in the Moreton region are displaying enzymatic adaptation, which has been reported previously for fish subjected to chronic exposure to organic contaminants. These potential interferences complicate interpretation of EROD activity from feral biota. It is, therefore, suggested that future monitoring combine the two methods by applying passive sampler extracts to in vitro EROD assays. 相似文献
In natural systems, mixing is driven by turbulence, but current knowledge is limited in estuarine zones where predictions
of contaminant dispersion are often inaccurate. A series of detailed field studies was conducted in a small sub-tropical creek
in eastern Australia. Hydrodynamic, physio-chemical and ecological measurements were conducted simultaneously to assess the
complexity of the estuarine zone, notably the interactions between turbulence and environment. The measurements were typically
performed at high frequency over a tidal cycle. The results provide an original data set to complement long-term monitoring
and a basis for a more detailed study of mixing in sub-tropical systems. Unlike many long-term observations, velocity and
water quality scalars were measured herein with sufficient spatial and temporal resolutions to determine quantities of interest
in the study of turbulence, while ecological indicators were sampled systematically and simultaneously. In particular the
results yielded contrasted outcomes, and the finding impacts on the selection process for key water quality indicators. 相似文献
Summary Measures of relative gamete contribution were related to degree of parental investment for both males and females from six groups of communally breeding pukeko (Porphyrio porphyrio). If there is a fitness cost to participation in parental duties, then for males parental investment should relate to degree of confidence of paternity while for females investment should relate to the number of eggs laid. Data were analysed in two ways: (1) by looking at individuals of the same sex within the same group to see if males that had a greater probability of paternity and females that had greater number of eggs in a nest subsequently invested relatively more in parental duties and (2) by pooling the data from the six groups and determining if there was a positive correlation between measures of presumed gamete contribution and amount of parental investment. The results from both types of analyses are variable and give no clear support for a positive relationship between presumed gamete contribution and parental investment even though a possible fitness cost is suggested. Factors which might influence investment are discussed. 相似文献
Environmental monitoring and conservation evaluation in terrestrial habitats may be enhanced by the use of invertebrate inventories, but taxonomic and logistic constraints frequently encountered during conventional taxonomic treatment have greatly restricted their use. To overcome this problem we suggest that nonspecialists may be used to classify invertebrates to morphospecies without compromising scientific accuracy. To test this proposition, large pitfall and litter samples of ants, beetles, and spiders from four forest types were sorted to morphospecies by a nonspecialist and to species by specialists. These data were used to generate morphospecies and species inventories and to estimate richness (α diversity) and turnover (β diversity), information frequently used in the above activities. Our results show that the estimates of richness of ants and spiders varied little between morphospecies and species inventories. Differences between estimates of beetle richness were largely influenced by errors of identification in two families, Curculionidae and Staphylinidae. But morphospecies and species inventories yielded identical ranking of forest type using richness. Turnover was assessed by sample ordination, which revealed similar clusters regardless of the type of inventory. Analysis of similarities of assemblages of ants and beetles showed significant differences between all forest types. Spider assemblages showed a lower level of discrimination. The assessment of turnover was consistent among inventories but different between the major taxa. Our findings suggest that morphospecies may be used as surrogates for species in some environmental monitoring and conservation, in particular when decisions are guided by estimates of richness and the assessment of turnover. 相似文献
Inventories of vertebrate and flowering plants are frequently used as surrogates for estimates of total biodiversity. This is in part because the inclusion of invertebrates and nonflowering plants is perceived as being too time-consuming, costly, and difficult because of the shortage of specialists. Estimates of the species richness of field samples of spiders, ants, polychaetes, and mosses made by a biodiversity technician and by specialist taxonomists were compared. The biodiversity technician received a few hours training in the taxonomy of each group and separated specimens into recognizable taxonomic units (RTUs). The specialists sorted to species. For the three animal groups the biodiversity technician recorded 165 taxa and the specialists 147, with the error for the ants and spiders being 13% or less. A small amount of splitting and lumping of species was detected. The concordance of estimates remained very similar when small subsamples were used. The procedure was repeated by 13 undergraduates using a subsample of spiders. Their average error was 14.4%. The greatest similarity in estimates was for the mosses, but with high levels of splitting and lumping this result was entirely fortuitous. The results suggest that RTU estimates made by biodiversity technicians may be sufficiently close to formal taxonomic estimates of species richness to be useful for the rapid assessment of biodiversity. They also show, however, that the procedures outlined here should be used on invertebrate and nonflowering plant groups before they can be confidently included in biodiversity surveys. 相似文献
This paper examines the minimum essential requirements that must be satisfied when a database is established for life cycle inventory calculations. It shows that the format of the database is governed by the physical requirements of the system being examined, by the need to include iterative calculations within the analysis and by the demands of the final data presentation. 相似文献
Objective: The few observational studies of the prevalence of high beam use indicate the rate of high beam use is about 25% when vehicles are isolated from other vehicles on unlit roads. Recent studies were limited to 2-lane rural roads and used measurement methods that likely overestimated use. The current study examined factors associated with the rate of high beam use of isolated vehicles on a variety of roadways in the Ann Arbor, Michigan area.
Methods: Twenty observation sites were categorized as urban, rural, or on a rural/urban boundary and selected to estimate the effects of street lighting, road curvature, and direction of travel relative to the city on high beam use. Sites were selected in pairs so that a majority of traffic passing one site also passed through the other. Measurement of high beams relied on video data recorded for 2 nights at each site, and the video data also were used to derive a precise measure of the proximity of other traffic. Nearly 3,200 isolated vehicles (10 s or longer from other vehicles) were observed, representing 1,500-plus vehicle pairs.
Results: Across the sample, 18% of the vehicles used high beams. Seventy-three percent of the 1,500-plus vehicle pairs used low beams at each paired site, whereas 9% used high beams at both sites. Vehicles at rural sites and sites at the boundaries of Ann Arbor were more likely to use high beams than vehicles at urban sites, but use in rural areas compared with rural/urban boundary areas did not vary significantly. Rates at all sites were much lower than expected, ranging from 0.9 to 52.9%. High beam use generally increased with greater time between subject vehicles and leading vehicles and vehicles in the opposing lane. There were mixed findings associated with street lighting, road curvature, and direction of travel relative to the city.
Conclusion: Maximizing visibility available to drivers from headlights includes addressing the substantial underuse of high beam headlamps. Advanced technologies such as high beam assist, which switches automatically between high and low beam headlamps depending on the presence of other traffic, can help to address this problem. 相似文献