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101.
102.
Natural and synthetic steroidal hormones can be carried to agricultural soil through fertilization with municipal biosolids, livestock manure, or poultry manure. The persistence and pathways of dissipation of [4-(14)C]-testosterone and of [4-(14)C]-17beta-estradiol in organic-amended soils were investigated using laboratory microcosms. Testosterone dissipation was investigated over a range of amendment concentrations, temperatures, and soil types. Under all conditions the parent compound and transformation products were dissipated within a few days. Addition of swine manure slurry to soil hastened the transformation of testosterone and 17beta-estradiol to the corresponding less hormonally active ketones, 4-androstene-3,17-dione and estrone. Two other testosterone transformation products, 5alpha-androstan-3,17-dione and 1,4-androstadiene-3,17-dione, were also detected. Experiments with sterilized soil and sterilized swine manure slurry suggested that the transformation of (14)C-labeled hormonal parent compounds was mainly caused by microorganisms in manure slurry, while mineralization of the hormones to (14)CO(2) required viable soil microorganisms. Organic amendments transiently inhibited the mineralization of [4-(14)C]-testosterone, perhaps by inhibiting soil microorganisms, or by enhancing sorption and reducing the bioavailability of testosterone or transformation products. Overall, organic amendments influenced the pathways and kinetics of testosterone and estradiol dissipation, but did not increase their persistence. 相似文献
103.
Observations were made on the influence of underwater divers on the behaviour of fish in Loch Torridon, on the west coast of Scotland. An electronically scanned sonar and a television camera were used to record the behaviour of 4 species common in the loch. These were the cod Gadus morhua (L), the saithe Pollachius virens (L), the pollack P. pollachius (L) and the common dab Limanda limanda (L). These fish were attracted to divers and to a sound source when the recorded noise from an aqualung and demand valve was transmitted into the water. By analysis and by testing different components of the noise it was shown that low frequencies between 30 and 110 Hz, generated by the release of exhaled air, were responsible for the attraction. It is suggested that the fish associated this noise with the presence of food organisms disturbed from the sea bed by the diver and that they had become conditioned to the noise over a period of time. 相似文献
104.
The intraspecific patterns of morphometric variation were examined in Fucus distichus L. and F. evanescens C.Ag., using samples gathered from 49 sites spread across the North Atlantic. Ten characters were measured on each plant. The data were subjected to bivariate regression analyses, canonical correlation analysis and nested analysis of variance (ANOVA). It was shown that the combined effects of the three environmental variables measured for each site (latitude, longitude and exposure) could only explain 23 and 15% respectively of the intraspecific morphometric variation. Inter-individual, within-site differences accounted for a further 62 and 53%. The remaining variation appears to be expressed on a geographic scale of tens of kilometres at most. Thus, the species seem to take the form of fine-scale phenotypic mosaics, superimposed on weak major clines. Such a pattern has not previously been described for any macroalga, although it is known in some angiosperms. 相似文献
105.
The objective of the present study was to investigate the population genetic structure of the commercially important camouflage grouper, Epinephelus polyphekadion (Bleeker, 1849), in the western and central Pacific Ocean to improve existing management. Camouflage grouper are widely distributed in the Indo-Pacific and form brief, seasonal, spawning aggregations that are often heavily fished. The present study examined populations sampled in 1997-1998 at five sites in the western central Pacific spanning a geographic distance of ~5,000 km: New Caledonia, Great Barrier Reef, Palau, Marshall Islands, and Pohnpei (Micronesia). Primer pairs were developed to examine genetic variation at three polymorphic microsatellite loci. Cluster analysis, using genetic distance, revealed three regional groupings: (1) Palau, (2) Pohnpei and the Marshall Islands, and (3) the Great Barrier Reef and New Caledonia. Highly significant allele frequency differences were observed among sites. At Pohnpei, significant allele frequency differences in successive years were also apparent, possibly related to genetic variation among cohorts or between local spawning groups. The inter-annual differences at Pohnpei suggest that there may be further genetic structuring over relatively modest distances, a finding relative to determining management units for this commercially valuable species and suggests that future studies need to incorporate possible small-scale temporal or spatial components into study design. 相似文献
106.
Juliana Jaramillo Eric G. Chapman Fernando E. Vega James D. Harwood 《Die Naturwissenschaften》2010,97(3):291-298
The coffee berry borer, Hypothenemus hampei, is the most important pest of coffee throughout the world, causing losses estimated at US $500 million/year. The thrips Karnyothrips flavipes was observed for the first time feeding on immature stages of H. hampei in April 2008 from samples collected in the Kisii area of Western Kenya. Since the trophic interactions between H. hampei and K. flavipes are carried out entirely within the coffee berry, and because thrips feed by liquid ingestion, we used molecular gut-content
analysis to confirm the potential role of K. flavipes as a predator of H. hampei in an organic coffee production system. Species-specific COI primers designed for H. hampei were shown to have a high degree of specificity for H. hampei DNA and did not produce any PCR product from DNA templates of the other insects associated with the coffee agroecosystems.
In total, 3,327 K. flavipes emerged from 17,792 H. hampei-infested berries collected from the field between April and September 2008. Throughout the season, 8.3% of K. flavipes tested positive for H. hampei DNA, although at times this figure approached 50%. Prey availability was significantly correlated with prey consumption,
thus indicating the potential impact on H. hampei populations. 相似文献
107.
Determining when contamination is pollution - weight of evidence determinations for sediments and effluents 总被引:1,自引:0,他引:1
Chapman PM 《Environment international》2007,33(4):492-501
Contamination is simply the presence of a substance where it should not be or at concentrations above background. Pollution is contamination that results in or can result in adverse biological effects to resident communities. All pollutants are contaminants, but not all contaminants are pollutants. Differentiating pollution from contamination cannot be done solely on the basis of chemical analyses because such analyses provide no information on bioavailability or on toxicity. Effects-based measures such as laboratory or field toxicity tests and measures of the status of resident, exposed communities provide key information, but cannot be used independently to determine pollution status. Laboratory studies can be predictive, but are rarely realistic. Measures of resident communities include innate natural variability and cannot easily distinguish between adaptation to contamination (a genetic process) and acclimation (a physiological process that may decrease energy reserves, possibly reducing such critical population-level parameters as reproduction). Finally, contaminant effects may not only be direct but also indirect; predicting such effects requires knowledge of the system under study as well as appropriate use of lines of evidence (LOE) such as toxicity tests directed to key species. Consequently, in sediments, effluents or other inputs/environmental compartments, determining when contamination is or may in future become pollution, requires a weight of evidence (WOE) assessment using different LOE appropriate to the situation under investigation. WOE investigations provide two different types of information: definitive conclusions regarding pollution; or, information as to what additional, investigative studies are necessary for definitive conclusions. Effectively, a WOE assessment comprises an initial screening-level ecological risk assessment (ERA), which may be followed by a detailed-level ERA if key uncertainties need to be resolved. 相似文献
108.
Urbanisation critically threatens biodiversity because of habitat destruction and novel selection pressures. Some animals can respond to these challenges by modifying their behaviour, particularly anti-predator behaviour, allowing them to persist in heavily transformed urban areas. We investigated whether the anti-predator behaviour of the Cape ground squirrel Xerus inauris differed in three localities that differed in their level of urbanisation. According to the habituation hypothesis, we predicted that ground squirrels in urban areas would: (a) be less vigilant and forage more; (b) trade-off flight/vigilance in favour of foraging; and (c) have shorter flight initiation distances (FID) when approached by a human observer. Observations were made in winter and summer at each locality. As expected, ground squirrels in urbanised areas were less vigilant and had shorter FIDs but did not trade-off between foraging and vigilance. In contrast, a population in a non-urbanised locality showed greater levels of vigilance, FID and traded-off vigilance and foraging. A population in a peri-urban locality showed mixed responses. Our results indicate that Cape ground squirrels reduce their anti-predator behaviour in urban areas and demonstrate a flexible behavioural response to urbanisation. 相似文献
109.
Núria Roura-Pascual David M. Richardson R. Arthur Chapman Tanja Hichert Rainer M. Krug 《Regional Environmental Change》2011,11(2):311-320
Invasive species alter the functioning of natural ecosystems, creating “novel ecosystems” comprising species occurring in
combinations with no analogs within a given biome. This poses major challenges for managers who cannot rely exclusively on
previous experiences. Multiple factors that drive invasion and which interact in complex ways demand innovative management
approaches. We show the utility of scenario planning in considering options for management in a region with substantial problems
with invasive alien plants: South Africa’s Cape Floristic Region. The approach allows us to identify the driving forces that
shape the status and trajectories of major woody invasive plants and to identify sensible strategies by considering a set
of scenarios based on the main uncertainties that encapsulate the linkages between the various components of the management
of biological invasions. Attitudes of landowners and management capacity are shown to be the crucial uncertainties influencing
the spread of major invasive species; axes based on these factors define our scenarios. Mapping current management projects
onto scenario axes highlighted key differences among areas. These insights can assist in directing particular management units
toward more desirable futures. Our study highlights the need to link social, political and legal constraints with ecological
processes to assure the effectiveness of management operations in controlling biological invasions. 相似文献
110.
Challenges of linking scientific knowledge to river basin management policy: AquaTerra as a case study 总被引:1,自引:0,他引:1
Slob AF Rijnveld M Chapman AS Strosser P 《Environmental pollution (Barking, Essex : 1987)》2007,148(3):867-874
The EU Project AquaTerra generates knowledge about the river-soil-sediment-groundwater system and delivers scientific information of value for river basin management. In this article, the use and ignorance of scientific knowledge in decision making is explored by a theoretical review. We elaborate on the 'two-communities theory', which explains the problems of the policy-science interface by relating and comparing the different cultures, contexts, and languages of researchers and policy makers. Within AquaTerra, the EUPOL subproject examines the policy-science interface with the aim of achieving a good connection between the scientific output of the project and EU policies. We have found two major barriers, namely language and resources, as well as two types of relevant relationships: those between different research communities and those between researchers and policy makers. 相似文献