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81.
A typology of land characteristics for the Humber catchment in central/eastern England is identified in relation to land
use, hydrology and demographic, topographic and geological characteristics, using GIS and statistical analyses. Empirical
relationships between land characteristics and water quality were examined in relation to the spatial variability in water
quality across the Humber catchment. Analyses of relationships between land characteristics and water quality were undertaken
at two hierarchical scales: (1) individual catchments and (2) localities of 10 km radius draining to each sampling site. The
importance of urban and agricultural sources was identified, together with a hydrological component linked to dilution of
point source inputs and mobilisation of specific sediment-associated contaminants in higher-energy (higher-flow) environments.
High-solubility (dissolved) chemical determinands (such as B, Cl and SO4), which undergo conservative transport through the river network, show the strongest linkages with land characteristics at
the catchment scale. Cr, Zn and Ca show stronger correlations with land characteristics at the locality rather than the catchment
scale, indicating that the concentrations of these determinands are more closely linked to the availability of localised sources.
This work provides a starting point for investigating how changes in land use and management of drainage basins might impact
river water quality at the regional scale and fluxes to the coastal zone, by providing a mechanism for examining linkages
between regional-scale land characteristics and river water quality. The next step requires development of the approach within
a more rigorous statistical framework and the extension of the regional analysis within a wider national and international
context.
Electronic Publication 相似文献
82.
P. A. Johnson 《Chemistry and Ecology》2013,29(3-4):215-229
The view is expressed that the assessment of disposal of nuclear waste in the ocean (specifically the Arctic and Kara Seas) is critical to understanding Arctic pollution. Much needs to be done in deciding what we should do, even though many wastes are long-standing and persistent. in 1993, disclosures about Russian dumping of submarine nuclear reactors, nuclear fuel, and other radioactive wastes into the Arctic Ocean brought this region and its problems into the world spotlight and raised public concerns about the resulting health and environmental risks. As a result of this concern, the Congressional Office of Technology Assessment published a 1995 study, Nuclear Wastes in the Arctic (US Congress Office of Technology Assessment, 1995). This paper summarises and updates that study. 相似文献
83.
《Environmental Hazards》2013,12(3):249-265
This paper discusses insights from post-tsunami early warning system (EWS) development in Thailand, Sri Lanka and Indonesia by analysing selected elements of resilience, based on the Coastal Community Resilience (CCR) framework, and by distinguishing between the cognitive, normative and procedural dimensions of EWSs. The findings indicate that (1) recent calls to develop participatory and people-centred EWSs as promoted by the Hyogo Framework for Action 2005—2015 have not been sufficiently translated into action in the implementation of national policies and strategies for early warning; (2) policy and guidance places significantly more emphasis on the procedural compared to the normative and cognitive dimensions of EWSs; (3) practitioners engaged in early warning and disaster risk reduction operate in contexts shaped by multiple stakeholder agendas and face considerable challenges in negotiating diverse needs and priorities; and (4) few platforms currently exist that enable stakeholders to coordinate and reconcile agendas, negotiate joint targets, share knowledge and critically reflect on lessons learnt, and to improve the integration of early warning with other priorities such as livelihoods improvement, natural resource management and community development. 相似文献
84.
选取福建西北部地区多群落类型组成的常绿阔叶混交林为研究对象,通过典型样地调查法,对生态系统各个层次进行取样调查,采用“相对生长法”计算乔木层生物量,灌木层、草本层和凋落物层采用全部收获法测得其生物量,对土壤层的调查采用剖面法加土钻法,代表性样品碳含量的测定采用重铬酸钾-外加热容量法。在此基础上,分析了该地区不同林龄常绿阔叶林生态系统碳储量及其格局特征,结果表明,(1)闽西北地区常绿阔叶林生态系统平均碳储量为260.63 t·hm-2。在每个发育阶段,各层片对整个生态系统碳储量的贡献率相对稳定,空间分布格局特征相似。幼龄林、中龄林、近熟林、成过熟林生态系统的碳储量分别为192.14、221.15、317.11和312.12 t·hm-2,基本表现出随林龄增加而逐渐增大的趋势。(2)乔木层、灌木层、草本层、凋落物层的平均碳质量分数分别为48.5%、46.9%、41.2%、44.0%,每个层片中,各器官的碳含量差异不大,乔木层、灌木层及草本层的碳质量分数表现出随层片高度降低而减小的趋势。土壤碳质量分数由表层到底层逐渐减小。0~10、10~20 cm土层碳质量分数均显著大于其余三个土层。(3)生物量碳储量在每个层片随着龄组不同,表现出不同的变化趋势。乔木层碳储量大小排序为近熟林﹥成过熟林﹥中龄林﹥幼龄林,灌木层与草本层在不同发育阶段的碳储量,均表现出以下规律:从幼龄林到中龄林不断增长,在中龄林达到最大值后,又随发育的进行显现出不断下降的趋势。随着地表凋落物现存量的不断增加,其碳储量也表现出幼龄林﹥中龄林﹥近熟林﹥成过熟林的趋势。土壤的平均碳储量为134.986 t·hm-2,随着林分发育,表现为成过熟林﹥近熟林﹥中龄林﹥幼龄林。 相似文献
85.
利用重庆23个气象观测站1960~2007年逐日最高气温观测资料,NCEP/NCAR再分析数据集中的高度场格点资料,运用EOF、REOF等方法,探讨重庆高温日数的空间分布特征,并对多高温天气的2006年和少高温天气年7~8月的环流特征进行了分析。结果表明:重庆高温天气主要出现在7~8月份,高温日数具有显著的年代际和区域性差异,20世纪70年代最多,80年代最少,沿长江、乌江为高温多发带。一致性异常分布是重庆高温日数的最主要空间模态;高温日数的异常空间分布可分为以下3个关键区:重庆中西部、重庆东南部、重庆东北部。乌拉尔山至鄂霍次克海地区阻塞高压偏弱,东亚大槽偏浅;100 hPa 高空南亚高压偏东,500 hPa 高空副高偏北偏西,形成一种上高下高的叠加形势是重庆7~8月出现多高温天气的主要原因。 相似文献
86.
Florencia Ornela Vilches M. A. Bobinac A. C. Labudía M. N. Paso Viola J. E. Marcovecchio H. L. Cappozzo 《Chemistry and Ecology》2019,35(6):501-523
Metals accumulated in the tissues of organisms inhabiting marine ecosystems generally reflect their bioavailable levels within that environment. The aim of this work was to study the presence and concentration of metals (Cd, Cr, Cu, Fe, Ni, Pb and Zn) and its bioaccumulation in liver-ink sac (n?=?12) and muscle (n?=?12) tissues of loliginid squids, Loligo sanpaulensis, in liver (n?=?15) and muscle (n?=?15) tissues of white croakers, Micropogonias furnieri, and in muscle (n?=?12) tissues of franciscana dolphins, Pontoporia blainvillei, as representatives of different trophic levels of an estuarial ecosystem from the southern coast of Buenos Aires. Except for Pb, all metals were detectable in the hepatic tissues. Bioaccumulation was observed for Fe, Cr and Ni in muscle of squids. Zn levels in muscle samples increased with the trophic level of the species analysed. Necochea-Quequén presents relatively high levels of Ni and Cr in the tissue samples of squids and fishes given other locations of southern hemisphere, indicating a possible anthropic enrichment. These outcomes provide the necessary basis for the environmental monitoring of an area with relevance for fishing and high anthropic activity. 相似文献
87.
Joseph Chung 《Disasters》1987,11(1):40-48
Tropical cyclones and hurricanes have a severe impact on the social and economic activities of affected communities. For small island nations in the Pacific region, the effects can be devastating because of their smallness. FQi and several other countries in the region are vulnerable to such disasters as they are situated in the zone where cyclones occur frequently.
During the last decade, the frequency of natural disasters and their adverse impact on die economic and social development of small nations like Fiji, has aroused awareness mat relief efforts must go beyond immediate "mopping up" operations to those which contribute to attaining longer term benefits through reconstruction and rehabilitation.
The paper outlines the 1985 agricultural rehabilitation program and discusses related issues and problems. 相似文献
During the last decade, the frequency of natural disasters and their adverse impact on die economic and social development of small nations like Fiji, has aroused awareness mat relief efforts must go beyond immediate "mopping up" operations to those which contribute to attaining longer term benefits through reconstruction and rehabilitation.
The paper outlines the 1985 agricultural rehabilitation program and discusses related issues and problems. 相似文献
88.
Nontraditional settlement patterns and typhoon hazard on contemporary Majuro atoll,Republic of the Marshall Islands 总被引:1,自引:0,他引:1
Dirk H. R. Spennemann 《Environmental management》1996,20(3):337-348
Low-lying islands and atolls are particularly prone to storm surges created by tropical depressions and typhoons. This paper presents a case study of traditional and contemporary settlement patterns of Majuro, the capital of the Republic of the Marshall Islands, and discusses its vulnerability to such storm surges. The paper shows that the application of traditional knowledge extends to the realm of urban planning and that, in fact, ignoring this traditional knowledge as expressed in pre-World War II settlement patterns, exposes urban development to increased flood hazards, a risk which may exact a price too high in life and property. 相似文献
89.
Gordon Brent Ingram 《Environmental management》1992,16(5):585-595
Islands with large tracts of primary rain forest constitute a distinct complex of terrestrial and marine ecosystems with global
significance because of high levels of biological richness or, in the case of oceanic islands, the evolutionary distinctiveness
of the organisms that they support. The myriad of small habitat units makes these settings particularly prone to fragmentation
and thus problematic for the conservation of biological diversity. Most of the remaining examples of islands with primary
rain forest are in the Pacific Rim, particularly in Indonesia, and there are threats from intensive timber harvesting, mining,
tourism, and dismemberment of traditional convervation systems. Prospects for inventorying, monitoring, and protecting the
remaining islands with relatively pristine successional mosaics of humid forest and shallow marine habitats within a framework
global monitoring are explored. Recommendations are made for a program of expanded use of the biosphere reserve designation
for rain forest islands and adjacent marine areas. 相似文献
90.
Ze'ev Gedalof David L. Peterson Nathan J. Mantua 《Journal of the American Water Resources Association》2004,40(6):1579-1592
ABSTRACT: A network of 32 drought sensitive tree‐ring chronologies is used to reconstruct mean water year flow on the Columbia River at The Dalles, Oregon, since 1750. The reconstruction explains 30 percent of the variability in mean water year (October to September) flow, with a large portion of unexplained variance caused by underestimates of the most severe low flow events. Residual statistics from the tree‐ring reconstruction, as well as an identically specified instrumental reconstruction, exhibit positive trends over time. This finding suggests that the relationship between drought and streamflow has changed over time, supporting results from hydrologic models, which suggest that changes in land cover over the 20th Century have had measurable impacts on runoff production. Low pass filtering the flow record suggests that persistent low flows during the 1840s were probably the most severe of the past 250 years, but that flows during the 1930s were nearly as extreme. The period from 1950 to 1987 is anomalous in the context of this record for having no notable multiyear drought events. A comparison of the flow reconstruction to paleorecords of the Pacific Decadal Oscillation (PDO) and El Nino/Southern Oscillation (ENSO) support a strong 20th Century link between large scale circulation and streamflow, but suggests that this link is very weak prior to 1900. 相似文献