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861.
深圳湾海域营养盐的时空分布及潜在性富营养化程度评价 总被引:7,自引:0,他引:7
根据深圳湾海域2008年2、5、8、11月4个航次的海水中营养盐监测数据,分析了深圳湾海域海水中营养盐的时空分布特征,应用Si:N:P比及潜在性富营养化评价模式对整个海域水质富营养化程度进行了评价。结果表明:深圳湾海域氮磷营养盐污染严重,劣于四类海水水质标准;且受珠江口水系夏季带来的高氮低磷低硅的海水的影响,整个深圳湾海水中氮磷硅营养盐的时空分布不尽相同:夏季DIN的分布由湾口向湾内逐渐降低;冬、春、秋3季DIN的分布和4个季节PO43--P、SiO32--Si的分布都是由湾内向湾口逐渐降低;受陆源输入的影响,秋季DIN和PO43--P表现出由西岸向东岸逐渐降低的趋势;受海底沉积物交换的影响,夏季SiO32--Si表现出由西岸向东岸逐渐升高的分布趋势。冬季整个海域都处于氮限制状态,基本无赤潮发生风险;春季整个海域基本处于富营养状态,是赤潮的高发期;夏季整个海域从湾内到湾口由氮限制逐渐过渡到磷限制状态,处于赤潮发生的危险期;秋季整个海域处于轻微的磷限制状态,也是深圳湾赤潮的高发期,但危险性较春季有所降低。 相似文献
862.
对酸性红壤施用石灰和N2O生成之间的关系进行了探讨。结果表明,在好气条件下,石灰的施用与NH4+氧化过程中N2O的产生量之间的关系不明显。但随着石灰施用量的增加,厌气条件下NO3-还原过程中N2O的积累量明显增加了,这与施用石灰后土壤pH升高而提高了硝酸还原酶活性有关。试验还表明,尽管在厌气条件下土壤pH较高有利于NO3-还原成NO2-,但当缺乏有效碳源时,NO2-向N2O的进一步还原受到限制,易发生NO2-的积累。 相似文献
863.
Assessment and Modelling of the Environmental Chemistry and Potential for Remediative Treatment of Chromium-Contaminated Land 总被引:2,自引:0,他引:2
864.
攀钢集团钛业公司选钛尾矿的综合利用 总被引:2,自引:0,他引:2
本文研究了攀钢钛业公司选钛尾矿的物质成分,提出了尾矿综合利用的途径:一是有益成分的分离、提取,二是利用尾矿或分选出来的矿物发展建材工业 相似文献
865.
Environmental Impact Assessment Under the National Environmental Policy Act and the Protocol on Environmental Protection to the Antarctic Treaty 总被引:3,自引:0,他引:3
US government actions undertaken in Antarctica are subject to the requirements of both the Protocol and the US National Environmental
Policy Act (NEPA). There are differences in the scope and intent of the Protocol and NEPA; however, both require environmental
impact assessment (EIA) as part of the planning process for proposed actions that have the potential for environmental impacts.
In this paper we describe the two instruments and highlight key similarities and differences with particular attention to
EIA. Through this comparison of the EIA requirements of NEPA and the Protocol, we show how the requirements of each can be
used in concert to provide enhanced environmental protection for the antarctic environment. NEPA applies only to actions of
the US government; therefore, because NEPA includes certain desirable attributes that have been refined and clarified through
numerous court cases, and because the Protocol is just entering implementation internationally, some recommendations are made
for strengthening the procedural requirements of the Protocol for activities undertaken by all Parties in Antarctica.
The Protocol gives clear and strong guidance for protection of specific, valued antarctic environmental resources including
intrinsic wilderness and aesthetic values, and the value of Antarctica as an area for scientific research. That guidance requires
a higher standard of environmental protection for Antarctica than is required in other parts of the world. This paper shows
that taken together NEPA and the Protocol call for closer examination of proposed actions and a more rigorous consideration
of environmental impacts than either would alone. Three areas are identified where the EIA provisions of the Protocol could
be strengthened to improve its effectiveness. First, the thresholds defined by the Protocol need to be clarified. Specifically,
the meanings of the terms “minor” and “transitory” are not clear in the context of the Protocol. The use of “or” in the phrase
“minor or transitory” further confuses the meaning. Second, cumulative impact assessment is called for by the Protocol but
is not defined. A clear definition could reduce the chance that cumulative impacts would be given inadequate consideration.
Finally, the public has limited opportunities to comment on or influence the preparation of initial or comprehensive environmental
evaluations. Experience has shown that public input to environmental documents has a considerable influence on agency decision
making and the quality of EIA that agencies perform. 相似文献
866.
PUA KUTIEL 《Environmental management》1999,23(3):401-408
area cells (the areas between the tracks) increased geometrically in the unprotected area, while the increase in the protected area
was linear; and (3) most area cells (50%–70%) in the protected area in each of the years analyzed (except 1944) were smaller
than 10 ha in size. However, an area cell greater than 100 ha has always been observed. In contrast, in the unprotected site
the number of area cells increased with time while their area size decreased. Twenty-seven percent of the unprotected area
is composed at present of area cells smaller in size than 1 ha. The development of a track system in the protected site changed
moderately with a few peaks during the past 50 years. This trend is a result of land management policies that actively promote
sustainable ecotourism. However, in the unprotected open area, the track system has changed continuously and drastically due
to a lack of land conservation management. 相似文献
867.
/ The management of lands adjacent to federally designated wilderness is increasingly seen to have the potential to negatively impact wilderness resources and management objectives. This paper first examines the numerous and often conflicting laws and regulations that influence how managers can mitigate transboundary issues. We then examine the various types of transboundary issues, and describe how they impact wilderness resources. Transboundary issues include recreational use, extractive activities, fire management, exotic species introductions, aircraft overflights and military operations, water diversion, urban encroachment, and transported pollutants. KEY WORDS: Adjacent lands; Buffer zones; Ecosystem management; Wilderness; Zones of influence 相似文献
868.
869.
烟碱对东方粉蝶幼虫觅食行为的影响和毒害作用 总被引:3,自引:0,他引:3
利用结球甘蓝、大白菜、蕹菜和莴苣菜4种蔬菜及东方粉蝶幼虫作为实验对象,以0%、0.01%、0.1%、1%和2%5种烟碱浓度梯度研究东方粉蝶幼虫对经过不同烟碱浓度喷洒过的4种蔬菜的觅食行为以及不同烟碱浓度对东方粉蝶幼虫的毒害作用.研究表明,在同一烟碱浓度下,东方粉蝶幼虫对4种蔬菜觅食行为及毒害致死时间差异不显著;不同烟碱浓度显著影响东方粉蝶幼虫对4种蔬菜的觅食数量和存活时间;烟碱浓度与东方粉蝶幼虫的觅食数量和对东方粉蝶幼虫的毒害致死时间呈显著负相关 相似文献
870.
The Precautionary Principle is a legal mechanism for managing the environmental risk arising from incomplete scientific knowledge
of a proposal's impacts. The Precautionary Principle is applied to actions that carry with them the potential for serious
or irreversible environmental change. The model proposed in this paper draws on methods used in a range of disciplines for
modeling (potentially highly nonlinear) interactions between multiple parts of a complex system. These methods have been drawn
together under the common mathematical umbrella of Fitness Landscape Theory. It is argued that the model, called “Environmental
Impact Fitness Landscapes,” allows statements about the sensitivity of the gross effect from a set of impacts to be made when the number of impacts in the set, and/or their degree of interaction, is varied.
It is argued that this can be achieved through identification of “meta” or “emergent” properties of the set itself, without
reference to the specific causal chains determining behavior in specific instances. While such properties are very general,
they may at least allow for the parameterization of the effects of sets of impacts where interactions are highly uncertain
and empirical data severely limited, i.e., situations that would typically invoke the Precautionary Principle. 相似文献