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451.
Hélène Hégaret Gary H. Wikfors Philippe Soudant Christophe Lambert Sandra E. Shumway Jean Baptiste Bérard Patrick Lassus 《Marine Biology》2007,152(2):441-447
The possible effect of Alexandrium spp. containing paralytic shellfish poisoning (PSP) toxins on the hemocytes of oysters was tested experimentally. In one
trial, eastern oysters, Crassostrea virginica Gmelin, were exposed to bloom concentrations of the sympatric dinoflagellate, Alexandrium
fundyense Balech, alone and in a mixture with a non-toxic diatom, Thalassiosira weissflogii (Grun) Fryxell et Hasle. Subsequently, another experiment exposed Pacific oysters, Crassostrea gigas Thunberg, to a mixed suspension of the sympatric, toxic species Alexandrium catenella (Whedon et Kofoid) Balech, with T. weissflogii. Measurements of numbers of oyster hemocytes, percentages of different cell types, and functions (phagocytosis, reactive
oxygen species (ROS) production, and mortality) were made using flow-cytometry. During and after exposure, almost no significant
effects of Alexandrium spp. upon hemocyte numbers, morphology, or functions were detected, despite observations of adductor-muscle paralysis in
C. virginica and measured toxin accumulation in C. gigas. The only significant correlation found was between toxin accumulation at one temperature and higher numbers of circulating
live and dead hemocytes in C. gigas. The PSP toxins are known to interfere specifically with sodium-channel function; therefore, the finding that the toxins
had no effect on measured hemocyte functions suggests that sodium-channel physiology is not important in these hemocyte functions.
Finally, because oysters were exposed to the living algae, not purified toxins, there was no evidence of bioactive compounds
other than PSP toxins affecting hemocytes in the two species of Alexandrium studied. 相似文献
452.
The Environmental Auditing Roundtable (EAR) is the single largest professional organization in the world, representing over 900 members. Built on a tradition of promoting environmental auditing through openly sharing experiences in the field of safety, health, and environmental auditing, the organization in recent years has significantly expanded its influence on auditing practices both nationally and internationally by monitoring audit activities and participating in the development of audit policy, regulation, standardization, and the certification of environmental auditors. This article describes the origin and evolution of the organization from meeting the needs of the membership to addressing the needs of external national and international stakeholders. 相似文献
453.
Historical aerial photographs (from 1946 through 1983) were used to study and describe the nature and extent of changes in wetland vegetation of a section of the St. Lawrence River and to evaluate the relative importance of water level, fire, and vegetational development as causal factors of these historical changes. Data were encoded and analyzed using a geographical information system, autocorrelation, and Mantel tests. Results show three temporal patterns in wetland dynamics. First, some wetland zones have been reduced by human activities (urbanization, landfilling, canal dredging). The second group consists of wetland areas that remain stable and do not change over time. They are generally protected sites artificially maintained by water-level control. A third situation has occurred in the Lake Saint-François National Wildlife Area, where no significant wetland losses were detected, but where landscape structure has changed greatly. Modeling with Mantel tests suggests that, in the latter case, these changes in wetland landscape are related to the suppression of burning (fires set deliberately by Indians) since the purchase of the territory by the Canadian federal government. This situation has caused rapid replacement of wet meadows byAlnus rugosa scrub and a possible decline in habitat diversity. 相似文献
454.
Trends and patterns in section 404 permitting requiring compensatory mitigation in Oregon and Washington,USA 总被引:1,自引:4,他引:1
Mary E. Kentula Jean C. Sifneos James W. Good Michael Rylko Kathy Kunz 《Environmental management》1992,16(1):109-119
The effects of permitting decisions made under Section 404 of the Clean Water Act for which compensatory mitigation was required
were examined. Information was compiled on permits issued in Oregon (January 1977–January 1987) and Washington (1980–1986).
Data on the type of project permitted, wetland impacted, and mitigation project were collected and analyzed. The records of
the Portland and Seattle District Offices of the US Army Corps of Engineers and of Environmental Protection Agency Region
X were the primary sources of information.
The 58 permits issued during the years of concern in Oregon document impacts to 82 wetlands and the creation of 80. The total
area of wetland impacted was 74 ha while 42 ha were created, resulting in a net loss of 32 ha or 43%. The 35 permits issued
in Washington document impacts to 72 wetlands and the creation of 52. The total area of wetland impacted was 61 ha while 45
ha were created, resulting in a net loss of 16 ha or 26%. In both states, the number of permits requiring compensation increased
with time. The area of the impacted and created wetlands tended to be ≤0.40 ha. Permitted activity occurred primarily west
of the Cascade Mountains and in the vicinity of urban centers. Estuarine and palustrine wetlands were impacted and created
most frequently. The wetland types created most often were not always the same as those impacted; therefore, local gains and
losses of certain types occurred. In both states the greatest net loss in area was in freshwater marshes.
This study illustrates how Section 404 permit data might be used in managing a regional wetland resource. However, because
the data readily available were either incomplete or of poor quality, the process of gathering information was very labor
intensive. Since similar analyses would be useful to resource managers and scientists from other areas, development of an
up-to-date standardized data base is recommended. 相似文献
455.
456.
457.
Blue Tits use fledgling quantity and quality as public information in breeding site choice 总被引:1,自引:0,他引:1
Public information (PI), which is the information that can be derived from the behavior and performance of conspecifics, has been demonstrated to be used in many fitness-enhancing decisions. In the context of breeding habitat choice, PI use has been called "habitat copying." We experimentally tested the existence of habitat copying in the Blue Tit (Cyanistes caeruleus), a nonmigratory, short-lived hole-nesting bird. We manipulated the mean number of fledglings raised locally (quantity) and their condition (quality) as components of PI by transferring nestlings from Decreased (D) patches to Increased (I) patches. Our manipulations caused a negative relationship between fledgling quantity and quality that does not exist naturally: I patches had a higher number of fledglings that were in poorer condition, whereas D patches had a lower number in better condition. Control (C) patches, whether manipulated or not, had intermediate levels in terms of fledgling quantity and quality. Adult emigration the following year was higher from D than from C or I patches. Similarly, adult dispersal distance decreased for individuals coming from D to C to I patches. This suggests that resident breeders rely mainly on fledgling quantity to make emigration decisions. Emigration patterns of juveniles did not vary in relation to our patch manipulation. Immigration rates were higher and similar in I and D patches than in C patches. Hence, immigrant Blue Tits seem to rely on one of the manipulated components of PI and are insensitive to the discrepancy between fledgling quantity and quality. This shows that even nonmigratory species, such as Blue Tits, may use PI in their dispersal decisions but weigh its components differently for emigration and immigration. Differences among species in the importance of PI in breeding habitat choices may be explained by differences in life histories. 相似文献
458.
Jörg Römbke Hella Hempel Adam Scheffczyk Hans Schallnass Michel Alvinerie Jean -Pierre Lumaret Jan Koschorrek 《Environmental Sciences Europe》2007,19(3):197-205
Goal, Scope, and Background
According to European legislation, an environmental risk assessment of veterinary pharmaceuticals for dung beetles is required if the substance is a parasiticide for the treatment of pasture animals. However, the demonstration of the environmental safety of those substances for dung beetles is strongly hampered by the fact that no standardized test system is available so far. Therefore, starting with recommendations from the SETAC advisory group DOTTS (Dung Organism Toxicity Test Standardization), a test system using the widespread temperate dung beetle species Aphodius constans was developed.Methods
Using experiences gained at the University of Montpellier (e.g. in field studies) and in other terrestrial tests, details of culturing and testing of A. constans were investigated in a project sponsored by the German Environment Protection Agency (UBA). Basically, the survival of young larvae of A. constans exposed to the test substance spiked into formulated (i.e. dried, grounded and re-wetted) or fresh dung is measured over a period of three weeks. Using the model substance dimethoate (an insecticide required as positive control in tests with the predatory mite Hypoaspis aculeifer) the suitability of the new test was checked. Afterwards, the new test method was used to determine the toxicity of four common veterinary pharmaceuticals (ivermectin, dicyclanil, moxidectin, praziquantel) in formulated and fresh dung. Finally, the effects of ivermectin on the dung beetles were determined in a test using fresh dung from treated cattle.Results and Conclusions
For Dmethoate LC50-values were found in a range of 1–3 mg a.s./kg dung (dew.), depending on the dung type. Praziquantel did not show eirecis in the tested concentration range (i.e. up to 1000 mg a.s./kg Dung (DW). The LC50-values of the other three pharmaceuticals were very low (<6 mg a.s./kg dung (DW)). With the exception of Dicyclanil no differences between formulated and fresh dung were identified. In the case of ivermectin the LC50-value were even lower: about 0.5 mg a.s./kg dung (DW). No differences between the results of test in which the substance was spiked into dung and those tests which were performed with dung from treated cattle were found. These results prove the sensitivity as well as the robustness of this test method.Recommendations and Perspectives
Based on the experiences reported here, it is recommended to standardize this test in an international ring test so that it can be incorporated in the risk assessment process for veterinary pharmaceuticals as described in the currently developed international registration guidelines. 相似文献459.
Felix Deutsch Jean Vankerkom Liliane Janssen Stijn Janssen Lszl Bencs Ren Van Grieken Frans Fierens Gerwin Dumont Clemens Mensink 《Ecological modelling》2009,217(3-4):230
The Eulerian Chemistry-Transport Model BelEUROS was used to calculate the concentrations of airborne PM10 and PM2.5 over Europe. Both primary as well as secondary particulate matter in the respirable size-range was taken into account. Especially PM2.5 aerosols are often formed in the atmosphere from gaseous precursor compounds. Comprehensive computer codes for the calculation of gas phase chemical reactions and thermodynamic equilibria between compounds in the gas-phase and the particulate phase had been implemented into the BelEUROS-model. Calculated concentrations of PM10 and PM2.5 are compared to observations, including both the spatial and daily, temporal distribution of particulate matter in Belgium for certain monitoring locations and periods. The concentrations of the secondary compounds ammonium, nitrate and sulfate have also been compared to observed values. BelEUROS was found to reproduce the observed concentrations rather well. The model was applied to assess the contribution of emissions derived from the sector agriculture in Flanders, the northern part of Belgium, to PM10- and PM2.5-concentrations. The results demonstrate the importance of ammonia emissions in the formation of secondary particulate matter. Hence, future European emission abatement policy should consider more the role of ammonia in the formation of secondary particles. 相似文献
460.
Michael R. Elliott Patricia F. Waller Trivellore E. Raghunathan Jean T. Shope Roderick J. A. Little 《Journal of Safety Research》2000,31(4):229-242
This analysis examines the ability of previous offenses to predict future high-risk offenses, and similarly, the ability of crashes to predict future high-risk crashes, using the complete driver history data (up to 9 years) for a set of young Michigan subjects. As expected, those with previous ticketed offenses or reported crashes are at greater risk for future offenses or crashes; with a previous-year serious offense doubling the odds of serious offenses during the subsequent year, and a previous-year at-fault crash increasing the odds of subsequent-year at-fault crashes by nearly 50%. There is modest evidence that serious offenses and at-fault crashes may better predict subsequent behavior in females and in more experienced drivers. This latter finding is also evidenced by the fact that records of these young drivers are less predictive of subsequent driving history than is true for records of all drivers in general found in other studies. This suggests that, in the early stages of driving, offenses and crashes are, at least in part, attributable to inexperience, and hence, characteristic of all beginning drivers. 相似文献