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991.
Response of Fish and Macroinvertebrate Bioassessment Indices to Water Chemistry in a Mined Appalachian Watershed 总被引:1,自引:0,他引:1
Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity
of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based
index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream
Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed,
West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed.
Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a
range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor
concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI
was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that
possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting
that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring
programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions,
and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite
of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery
of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain
biological integrity in mined Appalachian watersheds. 相似文献
992.
Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models 总被引:3,自引:0,他引:3
Haynes D Brodie J Waterhouse J Bainbridge Z Bass D Hart B 《Environmental management》2007,40(6):993-1003
Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities
is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World
Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation
of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral
reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic
pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or
stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef
water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships.
The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume
residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises
key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales.
Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant
burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness
of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the
Queensland and Australian Governments’ Reef Water Quality Protection Plan. 相似文献
993.
This study deals with the question of how winegrowing in Spain may be altered by anthropogenic climate change. The present state and expected future development of three bioclimatic indices relevant for winegrowing were assessed by observation, and four regional climate models from the EU-ENSEMBLES project were investigated. When comparing the 2061–2090 scenario period to the 1961–1990 reference period, the models unanimously indicate a significant increase in the mean of the two considered thermal indices over the entire study region. However, for the index based on temperature and precipitation, the models are heavily biased when verified against observations and generally disagree on the size of the projected future change. For this index, unanimous model agreement was only found for northwestern Spain where all models indicated a significant decrease in the mean. From these results, regional climate change is expected to negatively affect the quality of wine in the growing regions of central and southern Spain, and the Ebro valley, whereas positive effects should be expected in the northwest. No significant changes in the risk of mildew infestation are to be expected except for the northwest, where this risk is projected to decrease. 相似文献
994.
基于山西省2018—2020年国控点位O3监测数据分析了全省O3污染特征,分别以晋城市和太原市为典型城市,分析了温度、相对湿度和风向风速等气象因子以及前体物(NOx和VOCs)对O3的影响,并采用CAMx模式开展2020年6—8月山西省O3区域和行业来源解析. 结果表明:① 山西省O3超标天数中以O3轻度污染为主,且中度及以上污染呈增加趋势,O3污染集中出现在5—9月,且呈现较强的地域性特征,O3浓度日变化呈单峰型特征. ② ρ(O3-1 h)(臭氧1 h平均浓度)与气温、风速均呈正相关,与相对湿度呈负相关,高温、低湿有利于O3的生成. 风速与ρ(O3-1 h)呈分段式线性关系,ρ(O3-1 h)随着风速增大而升高,当风速大于某一阈值时,ρ(O3-1 h)随风速的增加而下降. 以典型城市晋城市为例,当温度在25 ℃以上、相对湿度在30%~60%之间、风速为4~5 m/s,且风向为南风和东南风时更容易出现ρ(O3-1 h)高值. ③ 山西省2020年6—8月O3区域来源解析表明,各城市O3本地源贡献较弱而传输贡献影响显著(>80%). ④ 山西省2020年6—8月O3行业来源解析表明,各市工业源类(电力源、焦化源和其他工业源)的贡献率在50%左右,柴油交通源贡献率在20%~27%之间. 研究显示,山西省O3污染传输贡献影响显著,联防联控势在必行,电力源、焦化源和柴油交通源对O3生成贡献较大,亟需优先加强管控. 相似文献
995.
Pigeons were released at two sites of equal distance from the loft, one within a magnetic anomaly, the other in magnetically
quiet terrain, and their tracks were recorded with the help of GPS receivers. A comparison of the beginning of the tracks
revealed striking differences: within the anomaly, the initial phase lasted longer, and the distance flown was longer, with
the pigeons' headings considerably farther from the home direction. During the following departure phase, the birds were well
homeward oriented at the magnetically quiet site, whereas they continued to be disoriented within the anomaly. Comparing the
tracks in the anomaly with the underlying magnetic contours shows considerable differences between individuals, without a
common pattern emerging. The differences in magnetic intensity along the pigeons' path do not differ from a random distribution
of intensity differences around the release site, indicating that the magnetic contours do not directly affect the pigeons'
routes. Within the anomaly, pigeons take longer until their flights are oriented, but 5 km from the release point, the birds,
still within the anomaly, are also significantly oriented in the home direction. These findings support the assumption that
magnetically anomalous conditions initially interfere with the pigeons' navigational processes, with birds showing rather
individual responses in their attempts to overcome these problems. 相似文献
996.
Zbigniew Kwieciński Zuzanna M. Rosin Łukasz Dylewski Piotr Skórka 《Die Naturwissenschaften》2017,104(5-6):39
Sex differences in the foraging ecology of monomorphic species are poorly understood, due to problems with gender identification in field studies. In the current study, we used experimental conditions to investigate the food preferences of the white stork Ciconia ciconia, an opportunistic species in terms of food, but characterised by a low level of sexual dimorphism. During a 10-day experiment, 29 individuals (20 females and 9 males) were studied by means of a ‘cafeteria test’ in which the storks’ diet consisted of mammals, birds, fish, amphibians, insects and earthworms. The storks preferred food characterised by high calorific and protein values such as mammals, birds and fish. Sexes differed strongly in their preferences; males preferred mammals, whereas females preferred birds. Moreover, females consumed insects and earthworms less often than males. Interestingly, males spent significantly less time foraging than females. We have demonstrated that the white stork exhibits clear sexual differences in food preferences which are mostly attributable to differences in parental duties, physiology and anatomy. 相似文献
997.
A new mass estimate for the dodo (Raphus cucullatus), based on the lengths of the femur, tibiotarsus and tarsometatarsus, is attempted. The obtained mean mass is 10.2 kg, which
is less than previous estimates based on other methods, which ranged from 10.6 to 21.1 kg, and much lower than the 50 lbs
reported by a seventeenth-century eyewitness. The new estimated mass, which is similar to that of a large wild turkey, seems
more realistic than previous ones and supports the hypothesis that contemporary illustrations of extremely fat dodos were
either exaggerations, or based on overfed specimens. Pictures of “fat” dodos may also have been based on individuals exhibiting
a display behaviour with puffed out feathers. 相似文献
998.
Samson Wakuma Abaya Nicodemus Mandere Mandere Niclas Winqvist 《Mitigation and Adaptation Strategies for Global Change》2011,16(5):585-596
A proactive strategy to respond effectively to health impacts related to climate variability, particularly within vulnerable
populations, is of vital importance. Such a strategy can be attained if health officials have a deep understanding of how
climate variability affects human health and if the resources available for the health care sector are sufficient. This study
assessed the perceptions and preparedness of health officials toward climate variability and health impacts in the Somali
region of Ethiopia. The resources available for the health care sector were also assessed. The results show that approximately
80% of health officials were aware of the relationship between climate variability and human health impacts, but the majority
of them were unable to project the future trend of related health problems in the region. The results also show an inadequate
availability of health care resources, particularly in regards to infrastructure, numbers of health professionals, and training
on climate variability and health. The results further revealed problems with poor living conditions, such as access to sanitation
and safe water, for the majority of people in the study area. Climate variability is thus one of the many factors exacerbating
the increasing trend of human health problems in the Somali region. Besides improving training to increase health officials’
knowledge of climate variability and human health impacts, the government should also address other factors that currently
hinder a successful response to increasing disease prevalence. 相似文献
999.
Nicolas Nantel-Fortier Ann Letellier Virginie Lachapelle Philippe Fravalo Yvan L’Homme Julie Brassard 《Food and environmental virology》2016,8(4):296-304
Viral contamination along the production chain is a significant concern in both food safety and livestock health. Pigs have been reported to act as a reservoir for zoonotic viruses, sometimes emerging ones, and epidemiological studies have shown direct links between the consumption of uncooked pork offal and cases of hepatitis caused by the hepatitis E virus (HEV) genotype 3 in humans. The presence of HEV in swine herds has been reported, but its dissemination in pork production environments is still unknown. To investigate viral contamination sources in the swine industry, 452 environment and fecal samples, including samples from livestock transportation vehicles, were collected over a period of 11 months from ten farms and one slaughterhouse that together represent a single production network. Hepatitis E virus RNA was detected by nested RT-PCR in 32 samples from both inside and outside farm buildings, on trucks, and, mostly, from fomites collected in the slaughterhouse yard, such as on a utility vehicle. Phylogenetic analysis showed a wide diversity of HEV genotype 3 strains, similar to human and swine strains previously found. According to the results of this study, the movements of trucks and utility vehicles might play an important role in HEV dissemination on a slaughterhouse site and throughout an entire network. 相似文献
1000.
C. Henry Obasi U. Martin Obidiegwu N. Godwin Onyeagoro O. Innocent Arukalam C. Genevive Onuegbu N. Francis Onuoha M. Chinomso Ewulonu 《Journal of Polymers and the Environment》2017,25(3):544-555
We report in this paper the transport of an aromatic solvent, xylene through palm pressed fibre filled low density polyethylene composites studied at three different temperatures (40, 60, and 80 °C) by conventional weight-gain method. The diffusion parameters were investigated with special reference to the effect of fibre content, temperature and particle size. The effect of alkali treatment on solvent uptake was also analyzed. The transport coefficients of diffusion, permeation and sorption were determined to evaluate the influence of interface bonding on transport properties. The van’t Hoff relationship was used to determine the thermodynamic parameters and was found that the estimated free energies of sorption were all positive, indicating non-spontaneity of the solubility of PPF/LDPE composites. The first order kinetic rate constant and swelling parameters were also evaluated. 相似文献