Content of mercury in leaves of Spartina alterniflora Loisel. in Georgia,U.S.A.: an update     

S.Y. Newell  R.E. Hicks  M. Nicora 《Estuarine, Coastal and Shelf Science》1982,14(4):465-469

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Hydrocarbon degraders from tropical marine environments   总被引：1，自引：0，他引：1  

Zinjarde SS  Pant AA 《Marine pollution bulletin》2002,44(2):118-121

Analysis of 20 samples of marine mud and water around Mumbai resulted in the isolation of 17 bacteria and yeasts all of which were able to degrade more than 10% of the supplied crude oil. The yeasts strains were important degraders of the aliphatic fraction of crude. All the isolated yeasts belonged to the genus Candida. Using biochemical tests these were identified as Candida parapsilosis, C. albicans, C. guilliermondii, Yarrowia lipolytica, C. tropicalis and C. intermedia. Y. lipolytica was the best degrader utilizing 78% of the aliphatic fraction of Bombay High crude oil. None of these isolates degraded the aromatic or ashphaltene fractions. All the isolates required aeration, nitrogen and phosphate supplementation for optimal degradation. Four out of the six yeasts are human pathogens.  相似文献   

佛坪自然保护区植物群落物种多样性与海拔梯度的关系   总被引：35，自引：4，他引：31  

岳明  张林静  党高弟  辜天琪 《地理科学》2002,22(3):349-354

用多元统计分析方法研究了佛坪自然保护区植物群落多种性及群落各生长型多样性特征沿海拔梯度的变化。结果表明：1）植物群落的Shannon指数与Simpson指数及物种丰富度与海拔梯度均呈显著负相关关系;2）乔木层的物种多样性沿海拔梯度的变化则体现了“中国高度膨胀”的规律,即中等海拔高度上多样性高而低海拔和高海拔多样性较低;3）灌木层丰富度指数在1600-1700m之间有个很不明显的峰值,而其它4个指标沿海拔呈单调的下降趋势;4）草本层植物多样性呈先降后升的趋势,在中等海拔高度较低。  相似文献   

Total and methylmercury in a Brazilian estuary,Rio de Janeiro     

Kehrig HA  Costa M  Moreira I  Malm O 《Marine pollution bulletin》2002,44(10):1018-1023

Guanabara Bay, in Rio de Janeiro state, is impacted by organic matter, oil and heavy metals. The present study evaluated the total mercury (THg) and methylmercury (MeHg) concentrations and the MeHg to THg ratio (%MeHg) in water samples from different points of the bay and in 245 organisms of three different trophic levels sampled between 1990 and 2000. Dissolved mercury concentration in estuarine water samples ranged from 0.72 to 5.23 ngl(-1). THg and MeHg in mussel, ranging from 11.6 to 53.5 microg THg kg(-1) wet wt. and 4.5-21.0 microg MeHg kg(-1) wet wt., varied according to sampling point and water quality. Planktivorous fish and mussel presented similar MeHg concentrations, meanwhile THg in planktivorous fish were lower than in mussel. Carnivorous fish showed higher THg and MeHg concentrations (199.5 +/- 119.3, 194.7 +/- 112.7 microg kg(-1) wet wt. respectively) than organisms from other feeding habits and lower trophic levels. There was a significant difference in the %MeHg among trophic levels: mussel presented lower MeHg percentage (33%) than planktivorous fish (54%) and carnivorous fish (98%).  相似文献   

Rare and vulnerable species in the mollusc communities in the mining subsidence reservoirs of an industrial area (The Katowicka Upland, Upper Silesia, Southern Poland)   总被引：1，自引：0，他引：1  

Iga Lewin  Adam Smoli&#x;ski 《Limnologica》2006,36(3):181-191

Pollution of the water environment by mining waters is a problem not only in Poland, but worldwide. This study investigated the mollusc communities in seven mining subsidence reservoirs affected by coal mine output (the Katowicka Upland, Upper Silesia, Southern Poland). The objective of the survey was to determine the relationship between the molluscs and their environments and to evaluate the ecological-conservation value of freshwater habitats which support rare and vulnerable molluscs. From 1993 to 2005, 23 mollusc species were recorded. Our result confirmed an invasion by Potamopyrgus antipodarum (Gray, 1843), whose density varied from 2 to 2422 individuals/m² in the waters of the Katowicka Upland. A few rare and vulnerable species were found, e.g. Acroloxus lacustris (Linnaeus, 1758), Hippeutis complanatus (Linnaeus, 1758), Ferrissia wautieri (Mirolli, 1960), Anodonta anatina (Linnaeus, 1758), Musculium lacustre (O.F. Müller, 1774) or Pisidium casertanum (Poli, 1791). Principal component analysis showed a positive correlation between mollusc density and pH, the concentration of chlorides, the total hardness, alkalinity and total dissolved solids, and a negative correlation between the number of species and phosphates. Because of the distinctive environmental features of the mining subsidence reservoirs in Czułów, the research area has provided a refuge for wildlife.  相似文献   

Restoration of submerged vegetation in shallow eutrophic lakes – A guideline and state of the art in Germany     

Sabine Hilt  Elisabeth M. Gross  Michael Hupfer  Harald Morscheid  Jens Mhlmann  Arnulf Melzer  Jens Poltz  Stefan Sandrock  Eva-Maria Scharf  Susanne Schneider  Klaus van de Weyer 《Limnologica》2006,36(3):155-171

One of the most serious problems caused by eutrophication of shallow lakes is the disappearance of submerged macrophytes and the switch to a turbid, phytoplankton-dominated state. The reduction of external nutrient loads often does not result in a change back to the macrophyte-dominated state because stabilising mechanisms that cause resilience may delay a response. Additional internal lake restoration measures may therefore be needed to decrease the concentration of total phosphorus and increase water clarity. The re-establishment of submerged macrophytes required for a long-term stability of clear water conditions, however, may still fail, or mass developments of tall-growing species may cause nuisance for recreational use. Both cases are often not taken into account when restoration measures are planned in Germany, and existing schemes to reduce eutrophication consider the topic inadequately. Here we develop a step-by-step guideline to assess the chances of submerged macrophyte re-establishment in shallow lakes. We reviewed and rated the existing literature and case studies with special regard on (1) the impact of different internal lake restoration methods on the development of submerged macrophytes, (2) methods for the assessment of natural re-establishment, (3) requirements and methods for artificial support of submerged macrophyte development and (4) management options of macrophyte species diversity and abundance in Germany. This guideline is intended to help lake managers aiming to restore shallow lakes in Germany to critically asses and predict the potential development of submerged vegetation, taking into account the complex factors and interrelations that determine their occurrence, abundance and diversity.  相似文献   

热带、亚热带作物引种气候咨询系统   总被引：1，自引：0，他引：1  

杜尧东  何健  梁凤娟  刘锦銮 《热带气象学报》2006,22(5):510-514

在建立大型品种、气候及农业气候指标数据库的基础上，依据农业气候相似原理，即采用对作物生长、发育和产量形成有决定意义的关键气候要素，开发出“热带、亚热带作物引种气候咨询系统”。该系统可迅速查询26000多个热带、亚热带作物品种的信息，世界20000多个站点的气候资料，计算针对某品种而言，广东86个站点与世界各地的农业气候相似程度，并输出农业气候相似专用地图。  相似文献   

First Record of Fossil Mesocupes from China （Coleoptera： Archostemata： Cupedidae）          下载免费PDF全文

TAN Jingjing HUANG Diying REN Dong 《《地质学报》英文版》2007,81(5):688-696

Three new fossil species of the genus Mesocupes of fossil cupedids,M.angustilabialis sp. nov.,M.latilabialis sp.nov.and M.collaris sp.nov.,are described from the Jiulongshan Formation of Inner Mongolia,China.These new species are the first three records of fossil Mesocupes in China as well as the oldest ones in the world now.This finding also extends the geographical distribution of this genus from Central to East Asia.In addition,based on the ratio of the length of the last to the penultimate abdominal ventrites of new beetles distinctly lower than that of the species from the Karabastau Formation,the age of Daohugou fossil-bearing beds might be older than that of Karatau assemblage and consequently of Middle Jurassic.  相似文献   

湖南洞庭湖地区土壤中Hg的来源   总被引：1，自引：0，他引：1  

张明杨忠芳  陈岳龙陈国光 刘红樱 《地质通报》2007,26(11):1463-1469

Hg污染已成为全球性的环境问题,尤其是Hg对土壤的污染,因其具有隐蔽性、不可逆性和长期性的特点,对陆生生态系统构成潜在的巨大威胁,因此查明土壤中Hg的来源非常重要。运用生态地球化学填图的指导思想,对湖南洞庭湖地区土壤剖面分析和成土过程研究后发现,表层土壤中Hg含量的高低与成土母质中Hg的含量有很好的对应性,成土过程对土壤中Hg的含量也有显著的影响。  相似文献   

内蒙古准格尔旗晚石炭世一早二叠世早期腕足类物种多样性与沉积环境     

Zeng Yong 《古地理学报》2007,(5)

以定性与定量相结合的研究方法,对内蒙古准格尔旗晚石炭世—早二叠世早期的腕足类物种多样性、沉积环境进行了综合研究,指出本区海进序列的腕足类物种多样性远高于海退序列;规模较大、具有一定水深的海进序列是腕足类辐射、分异、物种多样性升高的重要环境体系;本区腕足类辐射起步于晚石炭世早期之初,物种多样性出现了3次峰值(晚石炭世早期之中期、晚石炭世早期之晚期、晚石炭世晚期之中期),其中晚石炭世早期之晚期是本区腕足类物种多样性的顶峰期。  相似文献