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951.
亚硝酸盐氮对草鱼种耗氧率的影响及适应性研究 总被引:1,自引:0,他引:1
通过测定全血红蛋白和高铁血红蛋白及耗氧率,研究了草鱼种在NO-N作用下的生理变化和对NO-N的适应性,结果表明:ρ(NO-N)在O~4mg·L-1范围内可使草鱼种耗氧率增加,并于1mp·L-1和4mg·L-1处出现峰值和次峰值;经暴露处理的鱼种在恢复21d后,显示出对NO-N的适应性. 相似文献
952.
Effects of cadmium and zinc on oxygen consumption, ammonium excretion, and osmoregulation of white shrimp (Litopenaeus vannamei) 总被引:1,自引:0,他引:1
White shrimp, Litopenaeus vannamei, a globally important cultured prawn species, is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of Cd and Zn to L. vannamei, and to investigate their effects on gill functions, which have not been carried out in this species before, hoping to obtain some important significance. First of all, we examined the acute toxicity of cadmium (Cd) and zinc (Zn) to L. vannamei and obtained 24-, 48-, 72-, and 96-h medium lethal concentration (LC50) values of 2.58, 1.30, 1.14, and 1.07 mg Cd l−1 and 3.98, 2.14, 1.75, and 1.35 mg Zn l−1, respectively. Furthermore, we also found that exposure of shrimp to Cd or Zn caused an inhibition in oxygen consumption of 91.3% and 75.9% lower than that of the control. However, after separate exposure to Cd or Zn, elevations in ammonium excretion were obtained, which were 153.7% and 144.1%, respectively, higher than the control. It is most likely that elevations in ammonium excretion were related to decreased osmotic pressure of shrimp blood. Finally, the distribution of Cd and Zn within gills was also determined. 相似文献
953.
954.
中国城市化与城镇居民住房 总被引:4,自引:0,他引:4
王晓东 《中国人口.资源与环境》1998,8(1):81-85
随着住房制度改革的不断深入,我国城镇居民人均居住面积有所提高,居住水平有所改善。但是,中国城市化发展的特点很容易造成城镇居民居住水平提高的假象。本文分析了造成这些假象的原因。 相似文献
955.
综合调水前后苏州河下游水体耗氧特性比较 总被引:6,自引:0,他引:6
对综合调水前后的苏州河(北新泾下游)水体耗氧特性进行了定性与定量比较。结果表明,综合调水工程全面实施后,苏州河下游水体的还原性物质耗氧阶段消失,单位水体耗氧量大幅度下降,但难降解有机物阶段的耗氧量仍较高。耗氧动力学模拟计算表明,CBOD耗氧一级反应动力学速率常数(K)在综合调水前后变化不大,而硝化耗氧Logistic动力学速率常数(Kn-log)则明显提高。 相似文献
956.
T. K. Vlassova 《Mitigation and Adaptation Strategies for Global Change》2006,11(4):897-909
Three methods of gathering local and traditional knowledge of Indigenous Peoples were used to assess environmental changes
and human impacts in Russian boreal forest communities: structured interviews, followed by an unstructured interview, and
an education/training workshop. The most important environment changes reported by Indigenous Peoples included the disappearance
of animals and plants, climate changes, a decrease in forest and shrub area, and human impacts such as poaching, forests fires,
industrial logging, clearing of forests for firewood, and water pollution by industrial wastes and discharges. We propose
establishment of the Boreal Residents' Network for Socio-environment Assessments and Education for Sustainable Development
to acquire local and traditional knowledge as a supplement to scientific monitoring. The proposed approach would involve permanent
inhabitants living in a broad range of boreal forests to gather local and traditional knowledge and assessments. This could
lead to a meta-database to share with international networks. 相似文献
957.
958.
2004年中国石化济南分公司污水处理场优化工艺操作,在原油加工量比2003年增加24.2%、污水处理量比2003年增加23.6%的情况下,污水处理使用的药剂、浮选浮渣不但没有增加,反而有大幅度的降低,取得良好的经济效益和社会环境效益。 相似文献
959.
随着经济的发展,焦作市的环境受到的影响越来越大,而传统的GDP存在着固有的一些缺陷:预算体系经济增长指标存在片面性.因此,从环保的角度,焦作市迫切需要建立适合本地实际的预算模式.我们就是根据焦作市基本情况,通过实例分析,首次建立了焦作市绿色GDP核算体系,并确定了评价方法,给出了核算基础数据的获取来源,对焦作市绿色GDP核算中的各类实物量核算进行了研究,确定了环境污染实物量、环境治理成本实物量、环境质量数据、生态系统实物量、水资源和矿产资源等实物量核算表,同时对绿色GDP中官员考核指标进行了探讨,建立了一套较为完整的官员考核指标体系. 相似文献
960.
There is growing interest in the useof forestry-offset projects to mitigate increasingconcentrations of carbon dioxide in the atmosphere. If forestry-offset projects are to be employed broadlyand successfully there need to be accounting rulesthat are easy to operationalize and effective inpreventing cheating. Since carbon is both tangibleand predictable in where it occurs it is feasible todevelop simple accounting rules. Such rules must beconservative with respect to the amount of carboncredited.If accounting practices based on the following simplerules are employed, costs will be kept low andprojects will credit only carbon that is physicallypresent:Changes in living aboveground biomass must always be measured in forestry –offset projects.Belowground living biomass can be estimated from aboveground living biomass in forestry-offset projects. Generalized root/shoot ratios can be used as long as conservative ratios are applied.Not all changes in soil carbon stocks need to be measured, only those for which there is a possibility the stock is declining.The necromass pool need not be measured except when there has been a recent disturbance (interval varies with ecosystem). To insure that inaccurate techniques do not lead to overestimating of carbon stock changes, imprecise estimates of the carbon content of an ecosystem compartment should be discounted.There should be no required level of accuracy associated with estimates of carbon stock changes in forestry-offset projects, but the creditable carbon should be discounted proportional to the uncertainty. 相似文献