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901.
902.
Montevecchi W Fifield D Burke C Garthe S Hedd A Rail JF Robertson G 《Biology letters》2012,8(2):218-221
Animal tracking provides new means to assess far-reaching environmental impacts. In the aftermath of the Deepwater Horizon explosion in the Gulf of Mexico, a long-distance migrant, the northern gannet (Morus bassanus) suffered the highest oiling among beach-wrecked birds recovered. Analysis of bird-borne tracking data indicated that 25 per cent of their North American population from multiple colonies in eastern Canada migrated to the pollution zone. Findings contrasted sharply with available mark-recapture (band recovery) data. The timing of movement into and out of the Gulf indicates that immature birds would have absorbed most oil-induced mortality. Consequently, one of two outcomes is likely: either a lagged (likely difficult to assess) population decrease, or an undetectable population response buffered by age-related life-history adaptations. Tracking research is especially useful when little information on animal distributions in pollution zones is available, as is the case in the Gulf of Mexico. Ongoing research highlights current risks and conservation concerns. 相似文献
903.
Many assessments of water pollution in aquatic ecosystem have focused mainly on physical and chemical characteristics. However, until recently, biological aspects have been given little attention. Although physical and chemical methods of assessing water pollution are relatively simple to interpret, biological assessments have many strong merits. Therefore an attempt was made to use periphyton productivity (in terms of biomass ash‐free dry weight, AFDW) and chlorophyll‐a content (measured from periphyton colonized on glass microscope slides) to assess water pollution in the Linggi river. The Linggi River is a tropical lotic system in the country of Malaysia. As a result of increased nutrient enrichment due to sewage and agro‐industrial wastes, analyses of accumulated periphyton on glass slides showed increased biomass AFDW from an unpolluted upstream reach to the highly polluted downstream reach of the river. In contrast to biomass, the chlorophyll‐a content of the accumulated periphyton was not always directly related to the AFDW of the biomass. Though the highly polluted Station 4 showed high biomass AFDW and chlorophyll‐a, due to increased nutrient enrichment. The chlorophyll‐a values at slightly polluted Station 2 were lower than at the unpolluted Station 1. Meanwhile, the mean chlorophyll‐a content observed in Linggi river was relatively high as compared to previous studies carried out in Malaysia. When the Water Quality Index (WQI) was calculated using key chemical parameters linked to organic pollution, there was a significant correlation between chemical parameters, biomass AFDW, and chorophyll‐a. Though the chlorophyll‐a content increased with decreases in the WQI, similar to the biomass AFDW, the chlorophyll‐a values were found to be lower in slightly polluted Station 2 than unpolluted Station 1. Therefore it was not necessary that an increase in the biomass AFDW, due to nutrient enrichment, would always increase the chlorophyll‐a in accumulated periphyton (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
904.
西天目山金钱松树轮中五种金属元素的含量分析 总被引:1,自引:0,他引:1
本文报道西天目山金钱松(Pseudolarix kaempferi Cord.)木质部中铝、铁、钙、锰、锌5种元素含量和累积量自1711年以来的变化情况。1711~1900年期间,钙的含量(μg/g)明显增大,铁和锰稍有上升,而铝和锌则略有下降;最近25年来,铝、铁、锰元素的含量升高,而锌含量下降。1711~1900年期间,5种元素的累积量(μg/Yr)都轻微下降,但最近20~25年来,铁、铝、锰的累积量又明显上升,锌元素变化不大。笔者认为铝、铁、钙、锰、锌元素在1711~1900年出现下降,可能是由于植被遭破坏的缘故,而在近25年中,铝、铁、锰元素的急速上升,则可能是工业污染的结果。 相似文献
905.
906.
Microbial Source Tracking for Identification of Fecal Pollution 总被引:1,自引:0,他引:1
Sylvie Seurinck Willy Verstraete Steven D. Siciliano 《Reviews in Environmental Science and Biotechnology》2005,4(1-2):19-37
Fecal pollution is a serious environmental problem that affects many coastal and inland waters worldwide. Both human and animal
fecal pollution impose risks to human health from exposure to pathogenic bacteria, viruses, and protozoa. To assist authorities
with the implementation of the changes suggested by more restricted legislation concering water quality in Europe, methods
are needed which can identify the sources of fecal pollution. Management of fecal contamination of water would be improved
if the origin of the fecal pollution could be correctly identified since remediation efforts could then be allocated in a
more effective manner. The concept that the origin of fecal pollution can be traced has been termed microbial source tracking.
In microbial source tracking (MST) endogenous markers of fecal sources are used for identification of the fecal pollution
in aquatic environments. Chemical MST-methods can be used to trace mainly sewage pollution, but the used chemical targets
have no direct relationship with pathogenic bacteria. This is not the case in microbial MST-methods where source-specific
bacteria or viruses are cultured to identify fecal pollution sources. However, sometimes these microbial targets can be present
in too low numbers to be detected. This is circumvented by using molecular assays for host-specific marker detection. Phenotypic
and genotypic library-based methods can be used to discriminate among different fecal sources. However, the isolation step
makes this procedure very labour-intensive, and issues as temporal and geographical variability remain unresolved. The underlying
assumptions will be discussed and the methods mostly used in microbial source tracking will be described in more detail. 相似文献
907.
David Norse 《中国科学:生命科学英文版》2005,48(Z2)
Much of the research on the nitrogen cycle aims to improving scientific understanding but is not focused specifically on removing or reducing the scientific uncertainties that constrain policy makers in the formulation of appropriate responses to old or emerging environmental problems. Policy makers, for example, commonly find it difficult to assess the spatial or temporal importance of the various risks to human and ecosystem health that stem from man's interference with the natural N cycle. This paper will justify this conclusion by reference to the findings of a recent study on non-point pollution from crop production in China. The findings concern the perceived risks of groundwater nitrate to human health; uncertainties about critical NOX levels and their interactions with other pollutants; various other dimensions of man's impact on the N cycle. The paper will go on to suggest a more systematic process or pathway by which scientists can select and design their research in a manner that could give more effective support to policy makers. 相似文献
908.
John Keith Syers 《中国科学:生命科学英文版》2005,48(Z2)
Asia embraces a wide range of cropping environments, largely related to the diversity of climate. To meet the high food requirements of a very large population (some 59% of the earth's total) large inputs of mineral N fertilizer are required (44.2 Tg N·yr-1 in the mid 1990s). However, because of the low (20%-50%) overall efficiency of use of fertilizer N, sometimes coupled with heavy use in intensively-farmed areas (for example in parts of China), losses of fertilizer N from agricultural land are expected to be high. Part of the N lost is thought to cause pollution of the atmosphere and water resources. A sub-regional approach, based on the FAO Agroecological Zone (AEZ) concept, has the potential to provide meaningful assessments of the agricultural and environmental dimensions of N. The AEZ concept can also provide the rationale for locating Sub-regional Centers of the International Nitrogen Initiative (INI) by basing the considerations, as far as practicable, on agroecological conditions. 相似文献
909.
K. D. Lafferty 《Journal of fish biology》2008,73(9):2083-2093
In most aquatic ecosystems, fishes are hosts to parasites and, sometimes, these parasites can affect fish biology. Some of the most dramatic cases occur when fishes are intermediate hosts for larval parasites. For example, fishes in southern California estuaries are host to many parasites. The most common of these parasites, Euhaplorchis californiensis, infects the brain of the killifish Fundulus parvipinnis and alters its behaviour, making the fish 10–30 times more susceptible to predation by the birds that serve as its definitive host. Parasites like E. californiensis are embedded in food webs because they require trophic transmission. In the Carpinteria Salt Marsh estuarine food web, parasites dominate the links and comprise substantial amount of biomass. Adding parasites to food webs alters important network statistics such as connectance and nestedness. Furthermore, some free‐living stages of parasites are food items for free‐living species. For instance, fishes feed on trematode cercariae. Being embedded in food webs makes parasites sensitive to changes in the environment. In particular, fishing and environmental disturbance, by reducing fish populations, may reduce parasite populations. Indirect evidence suggests a decrease in parasites in commercially fished species over the past three decades. In addition, environmental degradation can affect fish parasites. For these reasons, parasites in fishes may serve as indicators of environmental impacts. 相似文献
910.
我国是世界上环境污染最为严重的国家之一, 环境治理工作日趋重要。随着分子生物学技术的发展, 在环境微生物学领域的科研工作者的不懈努力下, 我国在环境微生物学方面取得了许多重要成果, 使微生物在环境保护中发挥着越来越重要的作用。为了展现国内环境微生物科研工作者取得的最新进展,《微生物学通报》针对“第十次全国环境微生物学术研讨会” 组织出版了这期“环境微生物专刊”, 期望该专刊的出版有助于我国环境微生物学相关领域的交流和发展。 相似文献