红旗泡水生植物群落结构与功能的研究

红旗泡是松嫩平原上的水草型湖泊,１９７２年由引嫩干渠补入嫩江水,使其成为大庆市主要水源地和渔业基地。该湖水生植被分布面积大,覆盖近１／２的水面。本文分析了芦苇,狭叶香蒲和稗等单优群落的结构与分布,并统计了混合群落的数量特征。随着油田开发,大庆地区的水体均受到不同程度的污染;因红旗泡水生植物资源丰富且其具清除油污、吸附重金属和沉降悬浮物等净化功能,故使其成为大庆地区水质最好和鱼产量最高的湖泊。     

污染预测的非线性参数模型

本文探索了Cr~（3 ）,Cr~（6 ）溶液浓度与绿豆幼苗根过氧化物酶活性之间的相关关系,建立了线性与非线性的数学模型,经相关指数,剩余标准差检验,找出了拟合度比较高的非线性参数模型．本文的结果为利用过氧化物酶活性增长率作为水环境受重金属污染的生物监测指标提供了理论依据．     

呼和浩特地区蔬菜污染现状综合评价

呼和浩特地区蔬菜污染现状综合评价杨在中（内蒙古大学,呼和浩特０１００２１）黄雅琴（内蒙古环境监测中心站,呼和浩特０１００１０）ＣｏｍｐｒｅｈｅｎｓｉｖｅａｓｓｅｓｓｍｅｎｔｏｎｐｏｌｌｕｔｉｏｎｓｔａｔｕｓｏｆｖｅｇｅｔａｂｌｅｓｉｎＨｕｈｅｈｏｔ．...     

Food habits of channel catfish in a reservoir receiving heated waters

The diet of channel catfish captured near the mouth of a channel carrying heated waters was not significantly different from the diet of catfish captured elsewhere in the same reservoir during the cool months of the year. In summer months, however, the diet of catfish captured near the effluent was significantly different from the diet of catfish from other locations and seemed to indicate that catfish were foraging in cool, deeper waters beneath the thermal plume.Department of Biological Sciences, North Texas State UniversityFinancial support for the study was provided by a Faculty Research Grant at North Texas State University.     

Why the evolution of resistance to anthropogenic toxins normally involves major gene changes: the limits to natural selection

Standard population genetic theory suggests that adaptation should normally be achieved by the spread of many genes each of small effect (polygenes), and that adaptation by major genes should be unusual. Such models depend on consideration of the rates of acquisition of adaptation. In practice, adaptation to pollutants and anthropogenic toxins has most frequently been achieved by the spread of major genes. A simple model is developed to explain this discrepancy, in which the determining factor is not the rate of spread, but the maximum response achievable under the two contrasting models of polygenic or major gene inheritance. In the short term, for a given mean and genetic variance, characters in which the additive genetic variance is produced by the segregation of many genes of small effect at intermediate gene frequencies are unable to produce as large a response to directional selection as characters in which the variance is caused by genes of large effect at low frequency. If the target for selection is a long way from the mean prior to selection (as it may well be for adaptation to novel anthropogenic stresses) then adaptation can only be achieved by species possessing major genes. The model is discussed with reference to the example of heavy metal tolerance in plants.     

A review of some physiological and toxicological responses of freshwater fish to acid stress

Synopsis Data relating to the specific effect of low pH on growth of freshwater fishes are ambiguous. Reproductive failure resulting from acid stress appears to be related to an upset in calcium metabolism and to faulty deposition of protein in developing oocytes. It appears that the ’no effect‘ level of pH depression for successful reproduction is around 6.5. Data on behaviorial responses of freshwater fish to acid stress and CO₂ are described. Most fish appear to be indifferent to pH within the range of approximately 10.5 to 5.5 and between 7.4 and 4.5 CO₂ appears to be the main directive factor. In cases of severe acid stress alteration of gill membranes and/or coagulation of gill mucus occurs and death due to hypoxia may result from a lengthening of the water-blood diffusion distance. Several reports agree that acid stress causes an upset of electrolyte homeostasis in fish but effects of low pH on osmotic permeability are largely lacking. Most hatcheryreared salmonids can tolerate pH 5.0 indefinitely but below this level the homeostatic electrolyte and osmotic regulatory mechanisms become inadequate. When fish are subjected to debilitating acid stress blood pH decreases possibly as the result of flux of H⁺ ions across gill membranes into the blood. This could change transepithelial potential and allow a blood, to-water diffusion of Na⁺ ions down an electrochemical gradient. Lowered ambient pH may interfere with gill calcium levels increasing permeability to both H⁺ and Na⁺ ions or an acidemia may occur as the result of a decrease in the excretion of metabolically produced H⁺ ions and CO₂. When the capacity of the buffer mechanisms is exceeded the blood pH drops and the capacity of hemoglobin to transport oxygen is decreased.     

The effects of mine drainage and organic enrichment on benthos in the river nent system,Northern Pennines

A preliminary survey of the benthic fauna of sites on the Nent system affected by elevated zinc levels, acid water and organic enrichment is described. Data on faunal composition are presented for 17 sites. A clustering technique was applied to the taxa/site matrix to demonstrate the degree of association between sites varying in zinc concentration. Chandler biotic scores were found to be lowest at sites affected by high zinc levels and/or dense growths of the alga Stigeoclonium tenue. The role of elevated zinc levels and algal growth in determining the diversity and abundance of benthos is discussed.     

宁德水产养殖区水质状况及驱动力分析

水产养殖对海岸带生态系统的水环境有显著影响,研究水产养殖地区的水质动态及其驱动力对海洋牧场建设和海岸带生态系统管理有着重要意义。以宁德为研究区域,基于2017年夏季和冬季水质监测和遥感影像等数据,通过地理信息系统技术和统计分析软件,分析了水产养殖区域的水质现状、水质变化和驱动力。结果表明,该海域水质处于重污染状态,富营养化水平较高。除了悬浮物和总磷之外,其他水质指标都呈现出显著的季节性差异,不同季节影响水质的因素也不相同。水质的季节性变化是初始水质状况、养殖活动和自然因素共同作用的结果。基于研究结果,笔者建议结合高分遥感技术对养殖区水面覆盖和利用进行监测,对养殖类型和行为(如饵料类型和投放方式)进行调控,开展水质长期监测和风险应急管理,保障海洋牧场社会经济效益的同时降低生态环境影响、防控生态和人体健康风险。