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1.
Longhurst J 《Environmental monitoring and assessment》2005,111(1-3):27-42
Denmark has a long tradition of monitoring the aquatic environment. Previous monitoring has mainly focused on loss of nutrients
and subsequent impacts on the biological structure in lakes and coastal areas. However, as part of the third Action Plan for
the Aquatic Environment more emphasis has been put on stream ecology. The present paper describes background, strategy and
content of the new NOVANA stream programme, which will run for the period 2004–2009. The new programme will encompass more
than 800 stations covering all stream types in Denmark and monitoring will include three biological quality elements (macrophytes,
macroinvertebrates and fish) as well as physico-chemical features and hydromorphological elements. In addition, the new programme
integrates monitoring of elements both in the stream itself and in the riparian zone. Compliance with important European Commission
Directives such as the Water Framework Directive and the Habitat Directive is discussed. 相似文献
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3.
Farming in higher latitudes is generally believed to benefit from a warmer climate due to extended growing season, reduced risk of frost, availability of more productive cultivars, and an opening potential of farming in northern locations. We analyzed the impact of climate change on production of cereals in Russia and found that this general perception of beneficiary effect of a warmer climate is unlikely to hold, primarily due to increasing risk of droughts in the most important agricultural areas of the country. Past impacts of droughts on food security throughout the twentieth century suggest that a number of adaptation options are available to mitigate the increasing risks of crop failure. We analyze the effectiveness of these measures in connection with a set of climate change projections, under two contrasting scenarios of interregional grain trade: “Fortress Market” and “Open Market.” 相似文献
4.
Budd R Bondarenko S Haver D Kabashima J Gan J 《Journal of environmental quality》2007,36(4):1006-1012
The shift in land use patterns within many urban areas has the potential to influence the magnitude and nature of nonpoint-source pollution. The presence of pyrethroid insecticides in urban surface streams is of particular concern due to the broad spectrum toxicity of pyrethroids to aquatic organisms and the widespread use of pyrethroid products for agricultural and urban pest control. Sediment samples were collected throughout a mixed land use watershed in southern California during two sampling periods and analyzed for a suite of pyrethroids. Bifenthrin and fenpropathrin were found most frequently in the sediment samples, with the highest concentrations associated with sites adjacent to large commercial nurseries. Sediments from residential areas or residential-commercial mixed areas had fewer detections and significantly lower concentrations than the nursery runoff sediments. No apparent difference was found between wet and dry season concentrations, which may be attributed to the fact that the lack of flow under dry weather conditions rendered pyrethroid residues immobile. Organic carbon-normalized sediment concentrations were poorly correlated with the freely dissolved pore water concentrations measured by solid phase microextraction (SPME), suggesting factors other than sediment organic carbon content should be considered when relating concentrations to potential toxicities. 相似文献
5.
Soil samples from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria contained very high concentrations of cadmium, lead and zinc (up to 140, 4900 and 5900 mg kg(-1), respectively). A roadside soil in a relatively uncontaminated area also contained high concentrations of the same metals (24, 1550 and 1870 mg kg(-1), respectively) indicating that the transport of ores could be a source of contamination. Even though the lead isotope ratios in all the samples fell within a very narrow range (for example, 1.186-1.195 for (206)Pb/(207)Pb), the samples could be differentiated into three distinct groups: ores ((206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of 1.1874-1.1884 and 2.4755-2.4807, respectively), current deposition (1.1864 and 2.4704-2.4711, respectively) and local background (1.1927-1.1951 and 2.4772-2.4809, respectively). Although most of the current deposition has its origin in the ores used at the smelter, up to 12% could be from other sources such as petrol lead. 相似文献
6.
Kate D. L. Umbers Nikolai J. Tatarnic Gregory I. Holwell Marie E. Herberstein 《Behavioral ecology and sociobiology》2013,67(3):439-447
Bright colours often communicate important information between conspecifics. In sexually dichromatic species where males exhibit bright colours, two hypotheses are often invoked to explain the function of the colour. First, if a male’s bright colour contains information about his quality, females may prefer brighter males. Equally, male colour may reliably provide other males with information about fighting ability or resource holding potential. In such circumstances, brighter males may win altercations and/or males may use rival colour to assess their likelihood of winning an interaction. In the chameleon grasshopper (Kosciuscola tristis), males but not females turn bright turquoise when their body temperature exceeds 25 °C. In this study, we tested whether the turquoise phase of colour change has a signaling role in inter- and intrasexual contexts. We predicted that females would prefer bright turquoise males over dull males, but found no evidence from several choice experiments to support this hypothesis. We also predicted that brighter males would win more fights than duller males. Whilst we did not find that brighter males won more fights in staged experiments, we found that the brightness of males who chose to enter fights was significantly correlated with their opponents’ brightness. Our results suggest that the brightness of males’ turquoise phase may provide competitors with important information about their rival’s fighting ability. 相似文献
7.
Adrian C. Gleiss Serena Wright Nikolai Liebsch Rory P. Wilson Brad Norman 《Marine Biology》2013,160(11):2981-2992
Activity patterns of animals often relate to environmental variables such as food availability and predation pressure. Technological advances are providing us with new tools to monitor and better understand these activity patterns. We used animal-attached data loggers recording acceleration and depth to compare activity patterns and vertical habitat use of whale sharks (Rhincodon typus) at Ningaloo Reef, Western Australia. Whale sharks showed a moderate reverse diel vertical migration but exhibited a clear crepuscular pattern in locomotory activity. Peak activity occurred at sunset, whereas vertical movement peaked prior to this. Typical ram surface filter feeding could be identified and occurred primarily during sunset and the first hours of night. At such times, direct observations indicated whale sharks were feeding on tropical krill swarms. Kinematic analysis of postural data and data from vertical movement suggests that whale sharks at Ningaloo spend ~8 min per day actively ram surface filter feeding. Considering the high biomass present in krill schools, it is estimated that whale sharks at Ningaloo have a similar energy intake as those at other aggregation sites. Diel patterns in activity and diving behaviour suggest that whale sharks have tuned their diving behaviour in anticipation of the formation of these high-density patches which appear to only be periodically, but predictably available at sunset. Our results confirm that diel patterns in vertical habitat selection and vertical movements do not necessarily reflect patterns in activity and foraging behaviour. Direct quantification of activity and behaviour is required in gaining accurate representation of diel activity patterns. 相似文献
8.
Nikolai W. F. Bode A. Jamie Wood Daniel W. Franks 《Behavioral ecology and sociobiology》2011,65(2):117-130
The theory of collective motion and the study of animal social networks have, each individually, received much attention.
Currently, most models of collective motion do not consider social network structure. The implications for considering collective
motion and social networks together are likely to be important. Social networks could determine how populations move in, split
up into and form separate groups (social networks affecting collective motion). Conversely, collective movement could change
the structure of social networks by creating social ties that did not exist previously and maintaining existing ties (collective
motion affecting social networks). Thus, there is a need to combine the two areas of research and examine the relationship
between network structure and collective motion. Here, we review different modelling approaches that combine social network
structures and collective motion. Although many of these models have not been developed with ecology in mind, they present
a current context in which a biologically relevant theory can be developed. We argue that future models in ecology should
take inspiration from empirical observations and consider different mechanisms of how social preferences could be expressed
in collectively moving animal groups. 相似文献
9.
散射光下铁(Ⅲ)-丙酮酸盐配合物还原铬(Ⅵ)的研究 总被引:1,自引:0,他引:1
研究了在散射光下铁(Ⅲ)-丙酮酸盐配合物对铬(Ⅵ)的光还原反应;考察了溶液pH、铁(Ⅲ)、丙酮酸钠、铬(Ⅵ)浓度对反应的影响;分析了铬(Ⅵ)光还原反应的动力学。实验结果表明:铁(Ⅲ)-丙酮酸盐配合物体系能在较弱的散射光下还原铬(Ⅵ)。在铬(Ⅵ)浓度为19.2μmol/L、铁(Ⅲ)浓度为10.0μmol/L、丙酮酸钠浓度为240μmol/L、pH为3.0、光照240min的条件下,铬(Ⅵ)的还原率达到99.7%。从表观动力学方程的反应级数看,铁(Ⅲ)的级数(0.83)最高,铁(Ⅲ)浓度是影响铬(Ⅵ)光还原反廊速率的主要因素.铁(Ⅱ)是铬(Ⅵ)光还原的主要还原剂。 相似文献
10.
Input of trichloroacetic acid into the vegetation of various climate zones--measurements on several continents 总被引:2,自引:0,他引:2
Weissflog L Krüger G Elansky N Putz E Pfennigsdorff A Seyfarth KU Nüchter M Lange C Kotte K 《Chemosphere》2003,52(2):443-449
Trichloroacetic acid (TCA, CCl(3)COOH) is a phytotoxic chemical. Although TCA salts and derivates were once used as herbicides to combat perennial grasses and weeds, they have since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, the high-volatile C(2)-chlorohydrocarbons tetrachloroethene (TECE, C(2)Cl(4)) and 1,1,1-trichloroethane (TCE, CCl(3)CH(3)) can react under oxidative conditions in the atmosphere to form TCA and other substances. The ongoing industrialisation of Southeast Asia, South Africa and South America means that use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere can be expected to rise. The increasing emissions of this substance--together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the southern hemisphere--could lead to a greater input/formation of TCA in the vegetation located in the lee of these emission sources. By means of biomonitoring studies, the input/formation of TCA in vegetation was detected at various locations in South America, North America, Africa, and Europe. 相似文献