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131.
Reeds (Phragmites australis (Cav.) Trin. ex Steudel) are dying back at a fast rate in sizeable areas of Europe, with significant impacts on important wetland functions (biodiversity, stability of river and lake margins, water quality) and local economy. EUREED is a European strategic fundamental research initiative that aims at analyzing the mechanisms which control the growth dynamics and stability of reed-dominated ecosystems, at modelling and predicting how the ecosystem is disturbed by human activities and climate change, and at developing remedial management options. Expected achievements include (i) assessment of the functional role of reed-dominated ecotones as nutrient accumulators and transformers and as sources for atmospheric greenhouse gases, (ii) an ecosystem model capable of predicting future changes in ecosystem functioning in relation to climatic conditions, trophic status and water table management, (iii) assessment of genetic diversity of reed populations and its relation to die-back, and (iv) development of management tools, including preventative and restorative measures in relation to die-back. The project is carried out by research groups with complimentary skills and expertise from nine European countries. A reference study site is selected in each country as the basis for the field studies. The reference sites cover boreal-mediterranean and oceanic-continental climatic gradients, and the observational and experimental studies at these sites will permit interpolation between sites and extrapolation of results to the European scale. 相似文献
132.
铁对三角褐指藻生长、光合作用及生化组成的影响 总被引:15,自引:2,他引:13
近来许多研究表明,不论是在无机氮丰富还是贫乏的水域,铁元素的供应对于浮游植物的生物量、生长率、种类组成及初级生产力均会产生影响。通过室内培养,研究了铁对三角褐指藻生长、光合作用以及细胞生化组成的影响。实验结果表明,在其他营养盐充足的条件下,海水中铁浓度的变化对三角褐指藻的生长及光合作用均有显着影响。在5×10-7mol/dm3铁浓度时,三角褐指藻可达到其最大光合作用速率。在添加铁的条件下,三角褐指藻细胞多种生化组成受到不同程度的影响,其中叶绿素a含量变化幅度最大,增加了25%~35%,叶绿素c、类胡萝卜素含量也有一定程度的增加,但增长幅度要小于叶绿素a;碳水化合物的含量增加了5%~10%,蛋白质含量的增加幅度在5%~15%之间;超氧化物歧化酶(SOD)的活性及DCMU荧光增强比(Fd/F)也呈明显的增加趋势。铁是海洋初级生产过程中的一种限制因子。 相似文献
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原油WSF对三种海洋鱼类肝微粒体EROD活性的诱导和恢复的比较 总被引:1,自引:1,他引:0
研究了实验室条件下原油水溶性组分(WSF)暴露对黑鲷、黄鳍鲷和褐菖鲉肝微粒体EROD活性的剂量-效应,时间-效应和恢复过程。实验结果表明,在剂量诱导实验中,褐菖鲉肝EROD活性在原油WSF浓度为50μg/dm3时呈现生物统计学上的显著差异,而黑鲷和黄鳍鲷肝EROD活性在75μg/dm3时才呈现生物统计学上的显著差异;褐菖鲉肝EROD活性诱导倍数最高,但黑鲷的诱导浓度范围较广。在时间诱导实验中,在40μg/dm3原油WSF暴露下黄鳍鲷肝EROD活性在2 d时首先呈现显著差异;三种鱼肝EROD活性均在第4天达到最高,并呈现显著性变化,此后随着暴露时间的延长而逐渐下降并接近对照组水平。在恢复实验中三种鱼肝EROD活性下降并恢复到对照组水平。研究结果表明:对于石油污染物,黑鲷、黄鳍鲷和褐菖鲉肝EROD活性都可以作为污染生化效应监测指标,然而就三种鱼类比较而言,褐菖鲉最敏感,更适合于作为石油类污染及其生化效应,尤其是低剂量效应的监测生物。 相似文献
135.
Identifying barriers of species and characterize their effects on spatial distribution provide essential information to research
in landscape genetics. We propose a weighted difference barrier (WDB) method as an alternative to maximum difference barriers
(MDB), and to initiate and integrate more spatial modeling and methods into the problem solving process. Overall, WDB provides
quick and straightforward improvements to the drawbacks of MDB. WDB integrates more sample location relationships into the
barrier construction and reveals potential barriers that would otherwise go undetected. WDB incorporates both within group
and between group genetic information, and delineates the barriers as a more complex pattern.
相似文献
John RadkeEmail: |
136.
介绍了一种新型的生化需氧量(BOD)快速测量仪,其采用生物反应器法的工作原理.根据其对系列标准溶液的实测结果,采用A类的评定方法,做出了该仪器测量不确定度评定.该仪器测量不确定度分段表示更能反映实际情况,即在2~8 mg/L范围,用相对不确定度表示;在2 mg几以下时,用绝对不确定度表示.该仪器在2~8 mg/L范围的相对扩展不确定度U95rel=17.3%,与标准五日法相当. 相似文献
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For the population genetics analysis of the naturally grown brown seaweed Laminaria japonica (Laminariales,Phaeophyta) sampled from Dalian,Yantai,Weihai,Rongcheng and Qingdao in China,ten primers were employed to produce 88 bands as revealed by randomly amplified polymorphic DNA (RAPD) markers,and all these bands were polymorphic.According to these band patterns,there were 94 distinct phenotypes occurred in 100 samples indicating the high heterozygosity of this kelp.Dalian population samples showed the highest percentage of polymorphism (71.67%),and also the higher diversity estimated on the basis of the Shannon’s index (8.498),suggesting that this population could be chosen as the best resource for genetic breeding.The highest diversity of Yantai population possibly resulted from the introduction of L.longissima used for interspecific cross breeding with L.japonica cultivated in China.From Dalian southwards to Qingdao,the genetic variation of the five populations became less with a decrease in latitude,possibly due to the natural selection especially of high temperature.The genetic distance (Φ ST values) of the five populations was a little significantly correlated with the geographical distance (r=0.496) at P =0.05 by Mantel’s test.Weihai,Rongcheng and Yantai populations were closely grouped genetically together by Neighbor-joining cluster analysis probably in that the dispersal of the kelp by propagules more easily occurring in the range of relatively short distance.The analysis of molecular variance (AMOVA) also demonstrated that the relatively higher variation occurred among populations (71.49%) at an extremely significant level (P <0.000 1).All these evidence showed that there was a relatively distinct genetic differentiation among the sampled kelp populations,and L.japonica grown in China was also rather heterozygous in heredity. 相似文献