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201.
Lignite powered electric generation plants result in increasing environmental problems associated with gaseous emissions and
the disposal of ash residues. Especially, low quality coals with high ash content cause enormous quantities of both gaseous
and solid fly ash emissions. The main problem is related to the disposal of fly ash, which, in many cases, contains heavy
metals. It is known that toxic trace metals may leach when fly ash is in contact with water. In this study, fly ash samples
obtained from the thermal power plant in the town of Can in Turkey were investigated for leachability of metals under different
acidic and temperature conditions. The experimental results show that a decrease in pH of the leachant favors the extraction
of metal ions from fly ash. A significant increase in the extraction of arsenic, cadmium, chromium, zinc, lead, mercury, and
selenium ions from the ash is attributed to the instability of the mineral phases. These heavy metals concentrations increase
with respect to increasing acidic conditions and temperature. Peak concentrations, in general, were found at around 30°C. 相似文献
202.
通过分析位于钦州湾的2个海水水质自动监测站2009-2010年的自动监测数据,发现钦州湾水温、盐度、溶解氧季节变化明显,海水表层水温变化是引起钦州湾溶解氧含量变动的主要原因;钦州湾海水表层盐度及pH值主要受钦江、茅岭江径流及潮汐涨落的影响;处于河口区域,受大陆径流影响显著的海域使用海水水质标准来评价有欠妥当。 相似文献
203.
This study aimed to optimise the methodology for the use of Corophium insidiosum in a bioassay. Taking into account that it would be suitable to execute the bioassay with organisms having a good sensitivity
during the year and low mortality in control sediment, the influence of different temperatures (10–15–20 and 25°C) has been
examined. C. insidiosum was collected during August, November 2005 and January 2006, in Mar Piccolo basin (Ionian sea). The results obtained show
that this species mortality in the negative control sediment, ranged from 2.6 ± 0.6% at 10°C in August to 17 ± 2.2% at 20°C
in November, at different temperatures tested. At 20°C there were significant differences in mortality among different months
examined. Indeed no relationship among months was found at 15°C. Significant differences between August and November at 25°C,
between November and January were not found at 10°C. The 96-h LC50 values found for cadmium at all temperature experimental
conditions ranged from 2.11 mg/l (1.57–2.82) to 0.70 mg/l (0.54–0.93). The highest values were found at 10°C in November and
January. The results showed that the optimal temperature for the bioassay seems to be between 15°C and 20°C. Even if, at 20°C
the mortality differs significantly among organisms sampled. 相似文献
204.
隧道火灾和渗漏一直是隧道安全和健康的重要问题。基于分布式光纤测温系统(DTS)具有能实现在线实时监测且实测温度随光纤沿程分布这一技术特点和优势,将单根分布式光纤应用于隧道火灾的预警预报、火灾定位、隧道渗漏定位,属国内首创。本文介绍了DTS测温原理和实测成果。实测情况表明,DTS系统测温精确,抗干扰性强,特别适合隧道火灾预警预报和渗漏探测,具有良好的应用前景。 相似文献
205.
Dinara Sadykova Jostein Skurdal Alexander Sadykov Trond Taugbol Dag O. Hessen 《Ecological modelling》2009,220(20):2727-2733
In this study we explore a rather unique time series (1979–2002) of catch data of the crayfish Astacus astacus in Lake Steinsfjorden (SE Norway) in combination with temperature data and data on Canadian pondweed Elodea canadensis coverage. In 1977, E. canadensis was for the first time observed in the lake. Over the following years, the plant established dense covers over large parts of the shallow areas, excluding the crayfish from these areas and causing a sudden drop in population size. A size-structured model with bi-stability including a range of observed stage-specific life-cycle attributes (e.g. growth, fecundity, fertility, sex-ratio), population specific parameters and density-dependant (shelters, cannibalism, unspecified predators, competition between individuals, catch, number of traps) as well as density independent factors (temperature and Elodea coverage) were constructed to evaluate the various drivers for the population dynamics, and as a predictive tool for assessing the effects of future changes. Our model revealed that the decline primarily was due to density-dependant effect of the Elodea expansion with reduced number of hides and thus increased risk for predation and cannibalism, but also that temperature played an important role related to recruitment. The model should be relevant for crayfish stock management in general, and by demonstrating the major role of temperature, it is also relevant for predicting population responses under a changing climate. The model should also be applicable to other crustaceans and species with discrete growth and late maturation. 相似文献
206.
Gorgonian corals are long-lived, slow-growing marine species dominating Mediterranean rocky bottoms. Endowed with complex morphologies they give a structure to the whole community, moreover, being efficient suspension feeders, they play a key role in plankton-benthos energy flow and CO2 storage. Thus, the structure and the development of benthic, hard bottom communities are linked to gorgonian survival. The red coral Corallium rubrum (L. 1758) is a precious gorgonian endemic to the Mediterranean Sea. Harvested and traded world-wide since ancient times red coral is a clear example of overexploited marine resource. This species is structured into self-seeding, genetically differentiated populations, some of which, living in the shallower part of the species bathymetric distribution, was recently affected by anomalous mortality events linked to global climate change. The co-occurrence of overharvesting and mass mortality could dramatically affect such populations. Demographic population models, widely applied by conservation biologists to check population viability and to project population trends over time are fundamental to foster survival of such populations matching harvesting to population growth rates. Therefore we set out a dynamic model of a genetically differentiated red coral population living in shallow waters. This population is characterised by small/young, crowded colonies and high recruitment rate. On the basis of the size–age structure determined for this population, a static life-history table, in which survival and reproduction coefficients of the different size–age classes were reported, has been set out. Demographic data were included in a non-linear, discrete, age-structured dynamic model, based on a Leslie-Lewis transition matrix. Our field data indicate that the recruits-to-larvae ratio is actually density-dependent. Such dependence, positive for low and negative for high density values, was included into the model and the effect of colonies of different size–age classes on recruits-to-larvae ratio was considered to be proportional to the number of polyps they have. We applied such model to simulate the trends of the studied population under different increases of survival and life-span. As some populations of gorgonians actually show the dominance of sparse, big/old colonies and low recruitment rate, while others are characterised by crowded, small/young colonies and high recruitment rate, we simulated the shift from the former to the latter structure increasing survival and life-span. Our results suggest that a dramatic mortality increase of bigger–older colonies (due, in the case of red coral to overfishing) could have determined the population structure we found. 相似文献
207.
208.
Feng Zhao Xu Zhan Hai Xu Guangwei Zhu Wei Zou Mengyuan Zhu Lijuan Kang Yulong Guo Xingchen Zhao Zicong Wang Wei Tang 《环境科学学报(英文版)》2022,34(1):229-239
Eutrophication and harmful cyanobacterial blooms threaten water resources all over the world. There is a great controversy about controlling only phosphorus or controlling both nitrogen and phosphorus in the management of lake eutrophication. The primary argument against the dual nutrients control of eutrophication is that nitrogen fixation can compensate the nitrogen deficits. Thus, it is of great necessary to study the factors that can significantly affect the nitrogen fixation. Due to the dif... 相似文献
209.
Effects of incubation temperature on hatchling pine snakes: implications for survival 总被引:2,自引:0,他引:2
Joanna Burger 《Behavioral ecology and sociobiology》1998,43(1):11-18
Incubation temperature in ectothermic vertebrates affects incubation periods, and in some reptiles it affects sex ratios
and behavior. I present evidence that incubation temperature affects emergence and post-hatching behavior of pine snakes (Pituophis melanoleucus) that could influence survival in the weeks before hibernation. Hatchlings incubated at low temperatures remained in the
nest longer, had fewer alternate nest openings, and fewer underground tunnels to hide in than did hatchlings from warmer temperatures.
These conditions could render hatchlings from low-temperature nests more vulnerable to predation because, if a nest is opened,
they are not inside tunnels where they would be protected. Hatchlings from nests incubated at low temperatures took longer
to find shade during a thermoregulation test, and were less likely to move about in search of other cover than were those
from higher-incubation-temperature artificial nests. Similarly, hatchlings from nests with low incubation temperatures were
less responsive to a predatory stimulus and had a longer latency to strike than other hatchlings. Taken together, hatchlings
from nests with low incubation temperatures might be less able to avoid predators and find shade than those from nests incubated
at higher temperatures, and thus could be expected to have lower survival in nature.
Received: 21 July 1997 / Accepted after revision: 15 February 1998 相似文献
210.
The arctic tundra ponds at the International Biological Program (IBP) site in Barrow, AK, were studied extensively in the
1970s; however, very little aquatic research has been conducted there for over three decades. Due to the rapid climate changes
already occurring in northern Alaska, identifying any changes in the ponds’ structure and function over the past 30–40 years
can help identify any potential climate-related impacts. Current research on the IBP ponds has revealed significant changes
in the physical, chemical, and biological characteristics of these ponds over time. These changes include increased water
temperatures, increased water column nutrient concentrations, the presence of at least one new chironomid species, and increased
macrophyte cover. However, we have also observed significant annual variation in many measured variables and caution that
this variation must be taken into account when attempting to make statements about longer-term change. The Barrow IBP tundra
ponds represent one of the very few locations in the Arctic where long-term data are available on freshwater ecosystem structure
and function. Continued monitoring and protection of these invaluable sites is required to help understand the implications
of climate change on freshwater ecosystems in the Arctic. 相似文献