Biodeterioration of natural stone with special reference to nitrifying bacteria

An evaluation of field data from historical buildings in Germany showed that chemoorganotrophic bacteria are the most numerous microorganisms in building stones, followed by fungi and nitrifying bacteria. Chemoorganotrophic bacteria and fungi were present in almost every sample. Ammonia and nitrite oxidizers were found in 55 and 62% of the samples, respectively. Within months, natural stone was colonized by chemoorganotrophic microorganisms. The highest cell numbers were usually found near the surface. The colonization of natural stone by nitrifying bacteria took several years. The highest cell numbers were in some cases found underneath the surface. Nitrifying bacteria showed a preference for calcareous material with a medium pore radius between 1 and 10 m. Cell numbers of nitrifying bacteria did not correlate to the nitrate content of the stone material. We demonstrated that the stone inhabiting microflora can cause significant loss of nitrate by denitrification. Our data strongly suggested that microbial colonization of historical buildings was enhanced by anthropogenic air pollution. Samples taken from stone material with a pore radius 1 m had significantly higher cell numbers when they were covered with black crusts. A comparison of samples taken between 1990–1995 from buildings throughout Germany showed that in eastern Germany a significantly stronger colonization with facultatively methylotrophic bacteria and nitrifying bacteria existed. The same was true for natural stone from an urban exposure site when compared to material from a rural exposure site. Data from outdoor exposure and laboratory simulation experiments indicated that the colonization of calcareous stone by nitrifying bacteria was enhanced by chemical weathering.     

An application of nuclear magnetic resonance imaging to study migration rates of oil-related residues in estuarine sediments

Organisations such as the Marine Control Pollution Unit of the Department of Transport are at present testing the suitability of burial and landfarming of oily residues in sandy coastal environments as an alternative to landfill sites. The tendency for oil related compounds to sorb to sediments has been extensively investigated, but this has not permitted the 'observation' or measurement of advection/diffusion processes or the breakdown of these compounds within sediments.MRI, which is a multidimensional technique allowing the position of nuclei (most commonly protons) to be charted within a volume, provides a means of monitoring advection and diffusion of oil within sediments, thus offering a method of assessing the harming potential of oils in near-shore environments. A three dimensional MRI analysis of the movement of oil in an organic substrate and in three related estuarine sediments show that, using appropriate parameters, movement of the oil can be both observed and quantified. The results presented in terms of the % change of oil distribution within each sediment sample, show the great potential of MRI in studying protonated contaminants in these materials.     

A Regional Multiple-Stressor Rank-Based Ecological Risk Assessment for the Fjord of Port Valdez,Alaska

We conducted an ecological risk assessment of the marine environment of Port Valdez, a fjord in south-central Alaska. Because the assessment was regional rather than site-specific and contained a large number of different stressors in a variety of environments, we required a nontraditional method to estimate risks. We created a Relative Risk Model to rank and sum individual risks numerically within each subarea, from each source, and to each habitat. Application of this model involved division of Port Valdez into 11 subareas containing specific ecological and anthropogenic structures and activities. Within each subarea, the stressor sources were analyzed to estimate exposure of receptors within habitats leading to effects relevant to the chosen assessment endpoints. The subareas were analyzed and compared to form a Port-wide perspective of ecological risk. Available chemical concentrations from sediment and mussels collected from the Port were compared to various toxicological benchmarks as a partial confirmation of the risk analysis. An estimation of the risk of polycyclic aromatic hydrocarbons (PAHs) to marine invertebrates indicated low risk. The municipal boat harbor had the highest estimate, which reflected our relative risk rankings. The Relative Risk Model approach appears robust and has potential for use in situations where multiple stressors are of concern and for assessments covering broad geographic areas. In the Port Valdez assessment the approach provided relative risk rankings for chemical and physical stressors from various sources. But data were available for confirmation of risk estimates only for the chemical stressors. The rankings are relative, and extrapolation beyond the scenario in which they were developed is not warranted. Uncertainty is large, and the numerical scores collapse a multidimensional space into a single value. Use of just the numerical score out of context is more valid than with other indexes. The value of the approach lies in the relative rankings and the accounting of the components of the relative risk score.     

Interspecific variation in the response of fish to anthropogenic noise

1. Elevated levels of anthropogenic noise, especially those observed through boating activity, can negatively impact fish species, but it remains unclear which species are most affected and which behavioural metrics are best used in assessing fish responses to underwater noise. The effects of boat sounds on freshwater species are of particular interest because freshwater environments are less studied than the marine realm despite comparably high levels of biodiversity.
2. In the current study, we examine the behavioural responses to boat noise in two freshwater species that differ in their hypothesised response to sound inputs: the spottail shiner (Notropis hudsonius), a species with known hearing specialisations, and the bluegill sunfish (Lepomis macrochirus), a species with more generalised hearing capabilities. Fish were presented with boat noise in a laboratory setting, and their swimming, escape and foraging behaviours were assessed to examine differential responses in relation to hypothesised hearing abilities.
3. Both species showed a decrease in general swimming behaviours but an increase in erratic movements in response to boat noise, indicative of stress responses for both species. Despite the similarities in response based on swimming behaviours however, only spottail shiners exhibited true escape responses to the onset of the noise stimulus, suggesting a more extreme reaction in the species with a more refined hearing ability.
4. Taken together, these results show that freshwater fish can respond to increased levels of anthropogenic noise, but that the severity of the response may differ based on auditory structures and therefore presumed hearing ability. The differences seen between behavioural metrics used (swimming vs. escape responses) also demonstrate how care must be taken in choosing a metric when developing exposure guidelines for underwater sound exposures, as different metrics could lead to differential impact assessments.

     

近30年来青藏高原高寒草地NDVI动态变化对自然及人为因子的响应

草地生态系统是陆地生态系统的重要组成部分，在调节气候、水土保持、防风固沙、保护生物多样性等方面发挥着重要作用。青藏高原是全球海拔最高的独特地域单元，平均海拔超过4000 m，素有“世界第三极”之称，亦是我国重要的生态安全屏障，其对气候变化敏感且易受人类活动的影响，属于气候变化敏感区和生态脆弱带。近年来，由于气候变化和人类活动的不断加剧，青藏高原区域气候和环境发生了重大变化，气候变暖、水污染、草地退化和沙化等问题已严重阻碍了当地社会经济的可持续发展。高寒草地是青藏高原主要的植被类型，在气候变化和人类活动加剧的背景下，青藏高原高寒草地植被的动态变化受到人们的广泛关注。归一化植被指数（Normalized difference vegetation index, NDVI）因能有效地反映植被覆盖程度和生长状况而被广泛应用于植被动态的研究中。气温与降水被认为是影响青藏高原植被动态的主要气候因子，放牧强度与人口数量则是主要人为因子。因此，研究高寒草地植被对气候变化和人类活动的响应机制对预测未来草地变化有着重要的意义。基于青藏高原生长季草地的NDVI、气温、降水、放牧强度及人口数量等数据，在县区尺度上，采用趋势分析法探究了1982—2013年青藏高原143个县区生长季草地NDVI动态变化、气候变化及人类活动的变化，同时采用面板数据模型分析了32年来青藏高原143个县区气候、人为因子变化对草地NDVI变化的相对贡献。研究结果显示：（1）青藏高原高寒草地生长季NDVI总体呈增长趋势，草地植被生长状态呈现“整体改善、局部退化”趋势；（2）青藏高原生长季平均气温与降水量整体增加，气候呈现“暖湿化”趋势；（3）在长时间尺度上，气候因子主导了青藏高原高寒草地NDVI的变化，降雨和气温的增加促进草地NDVI的增加，放牧强度的持续增加则导致草地NDVI的减少。     

Traffic noise exposure affects telomere length in nestling house sparrows

In a consistently urbanizing world, anthropogenic noise has become almost omnipresent, and there are increasing evidence that high noise levels can have major impacts on wildlife. While the effects of anthropogenic noise exposure on adult animals have been widely studied, surprisingly, there has been little consideration of the effects of noise pollution on developing organisms. Yet, environmental conditions experienced in early life can have dramatic lifelong consequences for fitness. Here, we experimentally manipulated the acoustic environment of free-living house sparrows (Passer domesticus) breeding in nest boxes. We focused on the impact of such disturbance on nestlings’ telomere length and fledging success, as telomeres (the protective ends of chromosomes) appear to be a promising predictor of longevity. We showed that despite the absence of any obvious immediate consequences (growth and fledging success), nestlings reared under traffic noise exposure exhibited reduced telomere lengths compared with their unexposed neighbours. Although the mechanisms responsible for this effect remain to be determined, our results provide the first experimental evidence that noise alone can affect a wild vertebrate''s early-life telomere length. This suggests that noise exposure may entail important costs for developing organisms.     

Quantification of Heavy Metals in Mining Affected Soil and Their Bioaccumulation in Native Plant Species

Several anthropogenic and natural sources are considered as the primary sources of toxic metals in the environment. The current study investigates the level of heavy metals contamination in the flora associated with serpentine soil along the Mafic and Ultramafic rocks northern-Pakistan. Soil and wild native plant species were collected from chromites mining affected areas and analyzed for heavy metals (Cr, Ni, Fe, Mn, Co, Cu and Zn) using atomic absorption spectrometer (AAS-PEA-700). The heavy metal concentrations were significantly (p < 0.01) higher in mine affected soil as compared to reference soil, however Cr and Ni exceeded maximum allowable limit (250 and 60 mg kg^?1, respectively) set by SEPA for soil. Inter-metal correlations between soil, roots and shoots showed that the sources of contamination of heavy metals were mainly associated with chromites mining. All the plant species accumulated significantly higher concentrations of heavy metals as compared to reference plant. The open dumping of mine wastes can create serious problems (food crops and drinking water contamination with heavy metals) for local community of the study area. The native wild plant species (Nepeta cataria, Impatiens bicolor royle, Tegetis minuta) growing on mining affected sites may be used for soil reclamation contaminated with heavy metals.