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301.
G. Sarà C. Romano M. De Pirro P. H. Halldòrson M. Sprovieri P. Rumolo A. Mazzola 《Marine Biology》2008,154(1):191-198
The transfer of peat organic matter (OM) from tidal pools of upper littoral to downstream rocky shores and its potential incorporation
into marine biota were investigated using the stable isotope approach. Samplings were carried out in September 2004 in two
SW Icelandic sites (Osar and Hvassahraun), where we selected (1) areas with shores where grass gently declined towards rocks
and, on reaching the sea line, formed small tidal peat pools and (2) areas where grass and rocky shores were not contiguous,
rather the grass lower limits were several hundreds of meters back from the shore. In both grass and no grass areas, in the
intertidal zone, all benthic organisms and all potential OM sources were sampled. Dominant macroalgae were Ascophyllum nodosum ([Linnaeus] Le Jolis) and Fucus vesiculosus Linnaeus. In grass sites, organisms partially reflected the isotopic composition of peat OM, while in no grass sites, peat
represented only a negligible amount of available OM, or its signal was totally absent from the environment. Intertidal organisms
could rely on peat both directly by suspension feeding, grazing or scavenging and indirectly by predation (crabs) on low level
consumers (barnacles). 相似文献
302.
The Ozegahara peatland, in the Nikko-Oze National Park in Japan, is ecologically significant because of its oligotrophic environment; it is one of the most strictly preserved areas in the country. The isotope ratio of nitrogen (15N/14N) and carbon (13C/12C) and C/N ratio of peat moss (Sphagnum spp.) and sundew (Drosera rotundifolia) in the peatland were analyzed. The correlation of the isotope ratio with some parameters (sundew population density, number of trapped insects, water level, bog myrtle coverage, and visitor density) was investigated. The nitrogen isotope ratio of sundew showed the most significant covariation with visitor density, where sundew from lunch areas or along busy walkways showed a higher nitrogen isotope ratio. The nitrogen isotope ratio of peat moss covaried, not only with route traffic frequency but also with water level, bog myrtle coverage, and number of trapped insects by sundew, indicating that factors other than the visitor level influence the local nitrogen cycle. This study suggests that the nitrogen imported into the peatland by visitors is a principal factor to be monitored for the maintenance of the natural environment. 相似文献
303.
煤炭在世界各国的能源结构中都占有极其重要的地位,被工业界誉为“黑色的金子”。中国能源结构也以煤为主,煤炭资源的利用对人们的生产生活有着举足轻重的作用,其存放、运输和燃烧过程中向环境中排放大量有害、有毒物质,影响人体健康。非传统稳定同位素作为一种新兴的示踪剂,可以为上述过程提供示踪,逐渐在煤炭研究中得到应用。本文拟对煤炭研究中成熟的非传统稳定同位素(Li、B、K、Mo和Hg)的应用进行综述,包括不同地区煤中同位素特征以及煤中非传统稳定同位素在环境示踪方面的潜力。最后对煤中非传统稳定同位素前处理消解存在的问题、不同赋存状态、其他非传统稳定同位素和激光原位研究进行展望。 相似文献
304.
利用气相色谱/燃烧/同位素比值质谱(GC/C/IRMS)分析技术,采用NaHSO3与半胱胺衍生化方法,测定了气态乙醛在衍生化反应过程中的碳同位素效应,探讨了采用该方法测定大气乙醛碳同位素组成的可行性。试验测定了乙醛、衍生剂半胱胺及相应衍生物的碳同位素比值,结果表明,乙醛衍生物的δ13C测量值与理论值的偏差范围为0.11‰~0.35‰,在仪器精密度范围内(<0.50‰),即在衍生化过程中基本不会发生碳同位素分馏。采用该方法初步测定了大气中乙醛的碳同位素组成,实测数据显示,广州地化所和肇庆鼎湖山大气乙醛δ13C平均值分别为(-34.21±0.27)‰和(-31.23±0.16)‰,相同采样点的大气乙醛碳同位素组成基本不变,可见该方法可作为研究大气乙醛不同排放源的一种有效方法。 相似文献
305.
306.
生物壳体碳酸盐的稳定氧、碳同位素已经被大量地应用在古气候、古环境研究中。几十年的研究取得了很多重大成果,但是在生物壳体的就位分析研究中仍存在以下几个主要问题:生物壳体氧、碳同位素的解释问题;生物壳体时间序列的确定问题;就位分析研究壳体剖面的选择问题等。解决这些问题对于利用生物壳体提取高分辨率的古气候环境信息至关重要。文章针对这些问题进行了论述,并介绍了国内外为解决这些问题出现的新的研究方法及其最新研究进展。 相似文献
307.
用同位素示踪法测定微生物的葡萄糖摄入量,可能检测废水中有毒物质的生物毒性。实验结果显示:TCC/TCS对废水处理系统中厌氧菌的葡萄糖摄入有抑制作用,其抑制率与接触剂量的对数呈线性关系,但与接触时间却没有明显的线性关系。由此可见,TCC/TCS对微生物葡萄糖摄入的影响是复杂的。当生物处理系统中的微生物未接触TCC/TCS时,10%有作用浓度(EC10)和50%有作用浓度(EC50)分别为1.71mg 相似文献
308.
Rosenfelder N Bendig P Vetter W 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2706-2712
Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ13C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in 13C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in 13C because of more stable bonds between 13C and bromine. As a result, the δ13C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ13C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products. 相似文献
309.
Brown CJ Knight BW McMaster ME Munkittrick KR Oakes KD Tetreault GR Servos MR 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1923-1931
Fish community changes associated with a tertiary treated municipal wastewater effluent outfall in the Speed River, Ontario, Canada, were evaluated at nine sites over two seasons (2008) using standardized electrofishing. Habitat evaluations were conducted to ensure that the riffle sites selected were physically similar. The fish community was dominated by several species of darters that differed in their response to the effluent outfall. There was a significant decrease in Greenside Darter (Etheostoma blennioides) but an increase in Rainbow Darter (E. caeruleum) abundance directly downstream of the outfall. Stable isotope signatures (δ13C and δ15N), which indicate shifts in energy utilization and flow, increased in Rainbow Darter downstream, but showed no change in Greenside Darter. Rainbow Darter may be exploiting a food source that is not as available at upstream sites giving them a competitive advantage over the Greenside Darter immediately downstream of the outfall. 相似文献
310.
Stable nitrogen isotopic composition (δ15N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ15N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ15N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider’s guild designation and body size. 相似文献