气候变暖情景下黄河上游径流的可能变化

根据水文气象台站观测资料, 分析了全球变暖情景下黄河上游唐乃亥以上流域温度、降水和径流的变化状况, 并采用假定气候组合对未来数十年黄河上游唐乃亥以上流域的径流变化进行了预测. 结果表明: 黄河上游的温度与全球变暖有着明显的对应关系, 近几十年来, 流域各个地方的温度有不同程度的上升. 降水变化因流域各地所处位置、地势、地形的不同而差异较大, 受温度上升和主要产流区域降水大幅减少的影响, 近10余年来黄河上游的径流量呈持续递减的态势. 在未来几十年, 如果遭遇到气温升幅与降水减幅较大的"暖-干"气候组合时, 流域产水量将有较大的减幅; 当气温变化不大而降水增幅较大时, 流域产水量将有明显的增加, 同时由于冰雪及冻土融水的补给, 此气候情景下黄河上游唐乃亥以上流域径流量的增幅还将略大于降水量的增幅.     

试从土壤物质迁移与积累论亚热带北界的划分--以河南省伏牛山为例

对伏牛山中段南坡不同海拔高度7 个土壤剖面进行了野外调查和室内土壤理化分析,选择土壤氧化物迁移系数、硅铝铁率、活性铁与全铁之比、活性锰与全锰之比、Ba值、β值等指标,运用聚类分析等方法,从土壤物质迁移和积累角度深入探讨了河南省伏牛山南坡亚热带北界的划分。研究结果表明,该界线大约在海拔950 m左右。     

慢速扩张洋脊上的快速裂谷扩展

慢速扩张洋脊上的快速裂谷扩展ＭａｒｔｉｎＣＫ等２０年前就已经认识到了沿着洋中脊扩张轴的裂谷扩展。一般说来这一过程是随着两个扩张段之间的水平断错沿洋脊走向的移动,一个扩张段吞蚀另一扩张段而加长的过程。这个移动留下了一些倾斜于脊轴的假断层。测量扩展脊...     

侵蚀是陆内山脉生长的驱动机制

自然中的山脉作为局部构造特征可以在很长的时间内生长并维持。可是,如果根据现 岩石充变学知识,忽略地表过程,任何陆内山脉,当其宽度超过可以由岩石的强度所支持的程度时,将会在几十百万年内塌陷。例如,考虑由石英为主体的地壳流变性,使其地壳根侧向扩展遥结果,一条初始地形起伏为３ｋｍ高、３００－４００ｋｍ宽的山脉在大约１５Ｍａ内将被消减一半。我们认为地表过程事实上能够阻止这种“地下塌陷”。物质在高地形处的运     

<海洋地质与第四纪地质>论文分支学科分布的统计及几点启迪

科技期刊,特别是专业性比较强的学术期刊,衡量它是否具有较高的学术理论水平和应用价值,能否迅速转化为生产力,所登载文稿的被引用率和检索类刊物的收入率均是重要的评判标准,故深入研究登载论文的引文率的内涵,将有助于把握办刊方向、形成特色、早日步入“名牌”、...     

Cross-borehole flowmeter tests for transient heads in heterogeneous aquifers

Cross-borehole flowmeter tests have been proposed as an efficient method to investigate preferential flowpaths in heterogeneous aquifers, which is a major task in the characterization of fractured aquifers. Cross-borehole flowmeter tests are based on the idea that changing the pumping conditions in a given aquifer will modify the hydraulic head distribution in large-scale flowpaths, producing measurable changes in the vertical flow profiles in observation boreholes. However, inversion of flow measurements to derive flowpath geometry and connectivity and to characterize their hydraulic properties is still a subject of research. In this study, we propose a framework for cross-borehole flowmeter test interpretation that is based on a two-scale conceptual model: discrete fractures at the borehole scale and zones of interconnected fractures at the aquifer scale. We propose that the two problems may be solved independently. The first inverse problem consists of estimating the hydraulic head variations that drive the transient borehole flow observed in the cross-borehole flowmeter experiments. The second inverse problem is related to estimating the geometry and hydraulic properties of large-scale flowpaths in the region between pumping and observation wells that are compatible with the head variations deduced from the first problem. To solve the borehole-scale problem, we treat the transient flow data as a series of quasi-steady flow conditions and solve for the hydraulic head changes in individual fractures required to produce these data. The consistency of the method is verified using field experiments performed in a fractured-rock aquifer.     

Fisheries mismanagement

We analysed the extent to which European politicians have adhered to scientific recommendations on annual total allowable catches (TACs) from 1987 to 2011, covering most of the period of the Common Fisheries Policy (CFP). For the 11 stocks examined, TACs were set higher than scientific recommendations in 68% of decisions. Politically-adjusted TACs averaged 33% above scientifically recommended levels. There was no evidence that the 2002 reform of the CFP improved decision-making, as was claimed at the time. We modelled the effects of such politically-driven decision-making on stock sustainability. Our results suggest that political adjustment of scientific recommendations dramatically increases the probability of a stock collapsing within 40 years.In 2012 European fisheries policy will undergo a once-a-decade reform. Ten years ago radical reforms were promised but the changes failed to improve sustainability. It is likely that the 2012 reform will be similarly ineffective unless decision-making is changed so that catch allocations are based on science rather than politics.     

Integration of biochemical, histochemical and toxicogenomic indices for the assessment of health status of mussels from the Tamar Estuary, U.K

The aim of this study was to examine whether a combination of biochemical, histopathological and toxicogenomic data could be used as a valuable tool for the assessment of biological risk associated with pollutants within the Tamar River and Estuary, S.W. England, U.K. Accordingly, biochemical and histopathological biomarkers (protein carbonyls, lipofuscin, neutral lipids, lysosomal stability [N-acetyl-β-hexosaminidase and neutral red], lysosomal volume, ferric reducing antioxidant power [FRAP] and malonaldehyde [MDA]) and gene expression profiles were assessed in 5 sites from the Tamar River and Estuary (Neal Point, Town Quay, Wilcove, Cremyll Ferry and Whitsand; and a reference site, Trebarwith Strand, N. Cornwall). PAHs were measured in mussel tissue and sediment and metals were measured in mussel tissue only. Data from the biomarkers was integrated into a Mussel Expert System (MES) model to produce a simple assessment of mussel stress. Clear gradients of mussel toxicity were identified by the biomarkers (with the exception of neutral lipids) with the highest impacted animals found furthest up the Tamar, whilst the MES was unable to identify a gradient of effect. Gene expression profiles also indicated a gradient of stress with the greatest number of significantly up- or down- regulated genes found at the uppermost 2 sites. The MES did, however, determine that mussels from all sites, except the reference site, were highly stressed; a conclusion that could not be inferred from the biomarker data alone. It is concluded that the MES is a valuable tool that permits integration and interpretation of complex sets of biomarker data by identifying the biological meaning of biomarker changes.     

Estuarine conservation and restoration: the Somme and the Seine case studies (English Channel, France)

Megatidal estuaries such as the Seine and the Somme (North-Western France) are rather well delimited and human impacts on them are well understood. Since the middle of the 19th Century, there has been a slow but irreversible degradation of the state of these English Channel estuaries. However, current conservation and restoration strategies tend to freeze habitats in a particular state, their status being defined, most often, through a patrimonial or utilitarian approach. Connectedness between biotopes (sensu habitat+community) has a tendency to be neglected, especially with regard to main ecological gradients, i.e., salinity. In this paper, evaluation methodologies are proposed with the intention of assessing changes to ecosystem functions, under anthropogenic disturbance, controlled or otherwise. The Seine (a heavily industrialised ecosystem) is compared to the Somme (considered here for its pseudo-natural features) in order to discriminate between oceanic processes (siltation and plugging of estuaries) and anthropogenic influences. Preservation and restoration of habitats rely on a robust scientific methodology. The multi-scale approach adopted in the projects presented here relies on sensitive socio-ecological assessment procedures, tools for evaluating ecological quality, and well-built monitoring programmes based upon pertinent indicators. Such managerial tools were used to refine strategies and make them compatible with the sustainable co-development of resources in a European context. This paper demonstrates how scientists were able to acquire and apply knowledge in the field of rehabilitation and restoration. Jointly with managers and policy-makers, they have brought scientific information and socio-economics together in order to answer questions about the restoration of sites or habitats and to anticipate future propositions in the spirit of Integrated Coastal Zone Management (ICZM).     

试论伏牛山南坡土壤垂直分异规律——兼论亚热带北界的划分

在野外土壤调查和室内土壤理化分析的基础上,开展了伏牛山南坡土壤组成和性质垂直分异、土壤类型划分以及亚热带北界问题的讨论。研究表明：(1) 调查断面上土壤表层HA/FA随高度增加而增大,且均小于1,海拔900 m左右土壤胡敏酸的芳构化程度最低;随高度增加土壤pH和盐基饱和度先下降后上升;海拔900 m以下的土壤中均有明显的黏化层,向上土壤黏粒淋溶淀积逐渐减弱;海拔900 m以下的土壤土体风化程度高,大部分氧化物的平均迁移系数和土体淋溶率小于1,土体Saf小于5.06,淀积层游离铁含量大于20 g·kg-1,铁游离度大于40%,具有弱富铁铝作用,剖面中出现明显的铁锰新生体,而向上土体风化程度减弱,不发生富铁铝作用,剖面中不出现铁锰新生体。(2) 伏牛山南坡海拔550 m以下出现黏磐黄褐土 (饱和黏磐湿润淋溶土),550~950 m出现普通黄棕壤 (普通铁质湿润淋溶土),950~1900 m出现棕壤 (普通简育湿润淋溶土或暗沃简育湿润雏形土),1900 m以上出现暗棕壤性土或草甸暗棕壤 (暗沃冷凉湿润雏形土)。(3) 伏牛山南坡亚热带北界约在海拔950 m。