The Effect of Altered Habitat on Nitrogen Metabolism in Some Free-Living and Symbiotic Relationships Involving Nitrogen Fixing Organisms

Citrulline, one of the forms in which fixed nitrogen is assimilated in free-living blue-green algae and additionally in the blue-green algae/cycad symbiosis in Macrozamia, is similarly assimilated in the nitrogen fixing root nodules of Alnus glutinosa. By investigating the localisation of ornithine carbamoyl transferase in both cases it has been shown that in these symbiotic systems the ornithine carbamoyl transferase is only active in host tissue. This suggests that the host exerts an influence on the assimilation of fixed nitrogen in the microsymbiont resulting in the blocking of the enzyme trans-carbamylase with the subsequent excretion of the fixed nitrogen as ammonia to the host for further assimilation. This is discussed in the light of work on nitrogen metabolism in other symbiotic relationships involving nitrogen fixing organisms, where the effect of altering the habitat of the micro-organism has in fact resulted in a change in its metabolism.     

上海市蔬菜地土壤硝态氮状况研究

以上海市郊不同管理方式下菜地表层土壤采样测定土壤硝态氮含量为基础,并以水稻土等土壤作为对照,以期了解上海蔬菜地土壤硝态氮的现状,为菜地的合理施肥提出科学依据。结果表明,由于管理方式不同,土壤的硝态氮的NO3--N质量分数差异明显。大棚蔬菜地土壤中NO3--N明显高于其它其他用地管理方式下的土壤,依次为:w(大棚蔬菜地)>w(露天蔬菜地)>w(传统自留地),而且土壤硝态氮的积累是全剖面性的,而非仅在表层,如在80~100cm土层,大棚土壤硝态氮也为农田的好几倍。而且,大棚蔬菜地土壤盐渍化明显,主要特点之一是硝态氮积累,盐分高的土壤一般硝态氮也高。此外,长期大量的N肥投入引起了土壤酸化。土壤pH与土壤NO3--N质量分数呈线性负相关,经统计检验相关性达极显著水平。     

重庆金佛山岩溶区不同植被条件下土壤-植被系统CO2浓度日变化

对重庆金佛山典型岩溶区林地、裸地表层岩溶生态系统CO2浓度进行短时间尺度变化的野外观测结果表明,林地与裸地不同深处土温变化幅度由地表向土壤深部逐步降低,裸地地表温度和不同深度土温波动幅度均较林地大.林地与裸地各层次土壤CO2浓度变化与土温呈较好的相关关系.林地各层土壤CO2浓度波动微弱,变幅小于裸地.林地与裸地土层中CO2浓度随土层深度增加而增高.植被各层的温度和温度变化幅度从大到小依次为林层、灌层和草层.林层温度最大值滞后于气温约3 h.     

Concentration of ascorbic acid and innate immune effectors in <Emphasis Type="Italic">Engraulis ringens</Emphasis> and <Emphasis Type="Italic">Strangomera bentincki</Emphasis> during their main spawning period (2007–2008) in the Humboldt current system off Chile

In this study, we determined variations in ascorbic acid (AA) concentrations in the gonads and liver, and of the innate immune response (lysozyme activity and antiprotease) in the plasma of Engraulis ringens (anchoveta) and Strangomera bentincki (common sardine) during their reproductive seasons of 2007 and 2008 in the central area of the Humboldt Current. During the main spawning season in 2007, colder environmental conditions, higher phytoplankton biomasses, low dinoflagellate abundance and the dominance of large copepods in winter-early spring and of small copepods in late spring contributed to explain higher AA concentrations in anchoveta tissues. During the warmer year of 2008, lower phytoplankton biomasses, a notable increase of dinoflagellate abundance and the dominance of small-size copepods in winter and of larger copepods in spring occurred along with a drastic drop in AA concentrations in anchoveta tissues. These results contrasted with those in common sardine, a species in which AA did not vary as much as in anchoveta. An inverse trend between AA concentration in the liver and the gonadosomatic index suggested the AA utilization during gonadic maturation. Innate immune parameters were determined for the first time in small pelagic fish and constitute a new baseline data to evaluate their natural response to environmental changes. Changes in the distribution and abundance of edible taxa containing AA and edible for fish along with variations in AA in fish tissues during their reproductive season could become good indicators of the overall fish physiological condition resulting from variations in the trophic web structure.     

天津市区域土壤Cd污染及其对农产品影响

研究了天津市土壤Cd元素区域分布特征,依据本次土壤调查背景参数特征和国家环境质量标准对农田土壤Cd污染进行了分级评价,天津市农田土壤存在不同级别的Cd污染。其中中-重度污染区面积约116km2,占调查面积的1.07%,主要集中在东丽区大毕庄、荒草坨,津南区双港,西青区邓店、楼家院等。在不同污染程度区农产品的调查结果表明,Cd在中-重度污染地区蔬菜中有富集和超标现象,应加强污染区土壤监测和治理工作。     

近35a西藏那曲地区湖泊动态遥感与气候因素关联度分析

利用1976、1990、2000和2010年4期遥感影像对西藏那曲地区面积大于1 km2湖泊的动态变化进行信息提取,并结合1966—2010年研究区9个站点的气象数据,探讨其对气候变化的响应。结果表明,2010年那曲地区大于1 km2湖泊的总面积为16 841.93 km2,湖泊总数为469。近35 a那曲地区大于1 km2湖泊面积共增加3 505.12km2,增幅为26.28%,其中以2000—2010年增长速度最快,达18.18%;近35 a湖泊数量增加96,增幅为25.73%,其中以1990—2000年增幅最大,达13.38%。色林错面积从1976年的1 648.61 km2增加到2010年的2 332.55km2,超过纳木错成为西藏第一大咸水湖。1966年以来,那曲地区年平均温度、年平均最高温度、年平均最低温度、年平均相对湿度和年平均降水量总体呈上升趋势,年平均蒸发量呈下降趋势,气候朝暖湿方向发展,其中温度变化最明显,线性气温倾向率为0.51℃.(10 a)-1。湖泊动态变化与气象因子的灰度关联分析表明,气温升高引起冰雪融水增加、降水量增加、相对湿度增加和蒸发量减少,是近35 a来那曲地区湖泊面积和数量不断增加的主要原因。气象要素与湖泊面积间的回归方程表明,两者具有显著线性相关关系。     

中国华南地区持续干期日数时空变化特征

利用华南地区46个地面气象站1960-2012年逐日降水数据,分析该地区各季节持续干期日数的时空分布特征。结果表明：1）近53年来,华南地区春季和夏季的持续干期日数呈波动下降趋势,下降速率分别为0.042和0.108 d·（10 a）-1;秋季和冬季的持续干期日数呈波动上升趋势,上升速率分别为1.911和0.118 d·（10 a）-1。广东省春季和夏季持续干期日数呈下降趋势,下降速率分别为0.171和0.243 d·（10 a）-1;秋季和冬季持续干期日数呈增加趋势,增加速率分别为1.737和0.32 d·（10 a）-1。广西省春、夏和秋季持续干期日数呈增加趋势,增加速率分别为0.109、0.046和2.117 d·（10 a）-1;冬季为减小趋势,减少速率为0.106 d·（10 a）-1。2）华南地区持续干期日数在春季呈从北向南逐渐增多的趋势,夏季呈自西南向东北逐渐增加的趋势,秋季呈自西向东逐渐增加的趋势,冬季呈从北向南逐渐增多的趋势。冬季的持续干期日数是4个季节中最长的,大致在20~44 d。3）华南地区春季持续干期日数变化倾向率在-1.20~1.00 d·（10 a）-1之间,增加趋势最明显的区域是广西省的南部地区,减少趋势最明显的区域是广东省的沿海地区;夏季在-1.00~0.60 d·（10 a）-1之间,呈增加趋势的区域主要位于广西省的中部和南部,呈减少趋势的区域位于广东省大部分地区和广西省的东部;秋季在0~3.50 d·（10 a）-1之间,整体呈现增加趋势,变化倾向率较大的区域主要位于广西省的中部和广东省的东北部沿海地区;冬季在-1.50~2.00 d·（10 a）-1之间,呈增加趋势的区域主要集中在广东省的中南部和东部地区,以及广西的东部边缘,呈减少趋势的区域主要集中在广东省的北部以及广西的中部和西北部地区。持续干期日数增加趋势最明显的季节是秋季。4）持续干期日数与降水量表现出负相关性,与气温和无降水日数表现为正相关性。降水量和无降水日数的变化对持续干期日数的变化起着重要的作用,而温度对持续干期日数的影响比较小。     

淀山湖上覆水与沉积物孔隙水中重金属的分布特征

研究了淀山湖上覆水和沉积物孔隙水中Pb ,Cd,Cr,Cu ,Fe和Mn的浓度及Eh 分布 ,分析了孔隙水中重金属的扩散通量 .结果表明 ,淀山湖中重金属的浓度由高到低依次为 :Mn >Fe >Cr,Cu ,Pb >Cd ;Fe和Mn在孔隙水中的浓度远远大于它们在上覆水中的浓度 ,表层沉积物孔隙水中Pb ,Cd ,Cr,Cu的浓度稍大于它们在上覆水中的浓度 ;沉积物中的重金属可能按照浓度梯度经孔隙水从沉积物向上覆水中扩散而最终影响上覆水的水质     

pH、温度和水土比对酸性土壤溶液中铝离子形态分布的影响

溶液中Al3 、Al-F和有机络合态铝（Al-OM的浓度随pH降低而增加，Al3 在总单核铝中所占比例随pH的降低而增加，而Al-F络合物呈相反的变化趋势.土壤中铝的溶解度与土壤中铝氧化物的结晶形态有关，处于较高纬度地区的土壤，由于铝氧化物的结晶形态较差，在相同pH下，其铝的溶解度较大.土壤溶液中有机络合态铝的浓度随温度升高而增加，在pH不变的情况下，土壤中无机铝的溶解量随温度降低而增加.随水土比增加，土壤溶液中Al3 、Al-F络合物和Al-OM浓度减小，但按每kg土计算的铝溶解量随水土比的增加而增加.     

Environmental geochemistry studies in the area of Idrija mercury mine,Slovenia

Five centuries of mining and processing of mercury ore in the Idrija area have resulted in widespread contamination of different environmental compartments. Environmental impacts on a regional and local scale, caused by atmospheric emissions from the Idrija ore roasting plant, were established in the investigations of mercury spatial distribution in soil and attic dust in 160 km² area. Very high values were determined in the Idrijca River valley, and they decrease exponentially with the distance from Idrija. Mercury concentrations in attic dust are higher than in surrounding soils and the attic dust/soil ratio changes with distance. Measurements of mercury in the air confirmed widespread dispersion of mercury and showed highly elevated mercury concentrations around roasting plant and mine ventilation shaft. Beside, systematic monitoring of mercury contents in the stream sediments has demonstrated that huge amounts of mercury are stored in areas where ancient overbank sediments were deposited, and there was no decrease in mercury concentration in active sediments during the last 15 years. Recently, interesting and extremely polluted locations of historical small-scale roasting sites in the Idrija surroundings were discovered. Ongoing geochemical study aims to determine the extreme pollution and significance of these sites for wider contamination of soils and aquatic systems. Presented studies have shown that Hg mining in Idrija caused intense pollution of local and regional environment including the aquatic systems in the Gulf of Trieste, which is seen as the final sink of a major part of the Hg stored in soils and river sediments in the Idrija area.

     

广州市菜园土和蔬菜中镉含量水平及污染评价

探讨了广州市各区、市菜园土和蔬菜中的重金属Cd污染状况,测定了95份土壤样品以及292份蔬菜样品中的镉含量,并对广州市各区市菜园土中Cd污染程度进行了评价。研究结果表明,不同种类的蔬菜中,叶菜类对重金属Cd的吸收和富集较高,瓜豆类较低。蔬菜中重金属Cd的含量受土壤中Cd含量的影响。与国内其它城市相比,广州市蔬菜地土壤中的Cd平均含量处于较高水平;蔬菜则以海珠、番禺两区Cd含量相对较高,高于其它城市的含量水平。     

广东柘林湾养殖海域沉积物中汞的分布、累积及其生态风险

柘林湾是广东省养殖规模最大的海湾之一,为了解养殖海域沉积物中汞的分布、累积及其可能产生的生态风险,于2008年1月在柘林湾海域采集了5个站位的柱状沉积物和3个站位的表层沉积物,对其中的总汞含量进行了测定,并对其含量分布、累积特征进行了分析.结果表明,柘林湾海域表层沉积物中总汞平均含量为0.0645μg·g-1,径流输入是其空间分布特征的主要影响因素;柱状沉积物表层部分总汞含量相对较低,但不同采样区域柱样中总汞含量的垂直分布却有着显著的差异,网箱养殖区主要是由于汞近40年来来源变小导致沉积物表层部分中的总汞含量较底层低,而贝类养殖区则由于沉积后的再迁移作用使汞在氧化还原边界层富集累积;利用潜在生态危害指数法和沉积物质量基准法对此次调查的沉积物中汞的潜在生态风险进行的评价表明,汞虽对底栖生物基本无负面效应,但其潜在生态风险程度达到了中等水平,尤其是养殖区2号站位28～36cm、4号站位20～32cm和48～56cm以及6号站位36～56cm柱样中的汞甚至达到了高的潜在生态风险程度.因此,养殖区次表层沉积物中较高含量的汞应当引起足够重视.     

荔枝叶片与土壤常量元素质量分数年周期变化研究

从１９９７年开始，对荔枝叶片和土壤常量有效养分质量分数、ｐＨ值的年周期变化进行了研究。通过统计学分析，初步探明叶片各元素质量分数季节性变化的模式及其特点，以及土壤有效养分质量分数、ｐＨ值年周期变化的趋势；分析了年周期变化中叶片与土壤分析值之间的相关性。     

Toxicological effects of mouse diet contaminated with tributyltin on the immune and neurological systems of C57BL/6 mice

Organotin compounds, widely used as antifouling agents, are known to bioaccumulate in the food chain. Among organotin compounds, tributyltin (TBT), a toxic and widespread contaminant, has become a serious factor in environmental pollution and is suspected of being immunotoxic in animals. The purpose of this study was to assess the effects of 80 µg of TBT per kilogram of body weight (kg bw), provided in food, on the immune and neurological systems of C57Bl/6 mice. Data showed that TBT increased the proliferation of T and B lymphocytes in both adult and juvenile female and juvenile male mice, but that it decreased the proliferation of both T and B lymphocytes in adult male mice. The macrophages activity in female and male juvenile mice was higher than in adults of both sexes. The natural killer cytotoxic activity was also increased in juvenile and adult males and females compared to the control groups. In the brain, we observed the presence of TBT in the hippocampus, the striatum, the cortex, and the cerebellum in both the male and female groups. The highest levels were observed in the cortex of females and males, while the lowest levels were found in the cerebellum. TBT also induced an increase in the levels of the antioxidant glutathione (GSH) in the striatum, the hippocampus and in cortical structures but not in the cerebellum where the levels of TBT are lower. Our findings indicate that TBT modulated the immune and nervous systems causing endocrine and nervous perturbations.     

污水灌溉区土壤肥力及酶活性特征研究

通过野外调查和采样分析,研究了石家庄栾城县不同污水灌溉时间（0-52a）和不同层位（0-100cm）耕地土壤肥力及酶活性的分布特征。研究结果表明：与清灌对照点相比,污水灌溉区表层（0-20cm）土壤有机质含量、全氮含量、全磷含量、蔗糖酶活性、脲酶活性和磷酸酶活性、亚表层（20-40cm）蔗糖酶活性、磷酸酶活性和下层（40-60cm）蔗糖酶活性均相对较高,而下层有机质含量、全氮含量和底层（60-100cm）全氮含量均相对较低。4层土壤阳离子交换量和过氧化氢酶活性较对照点均无明显的变化规律。表层土壤全氮含量、蔗糖酶活性和磷酸酶活性、亚表层有机质含量、蔗糖酶活性和磷酸酶活性、下层蔗糖酶活性与污灌时间之间均存在显著相关性沪〈0．05）。上述特征反映了土壤肥力及酶活性对污灌的响应具有明显的层位效应和非同步性,而这些响应是由于污水中的营养物质输入土壤后引发微生物活性提高的“激发效应”所致。     

Comparison of Ground Water Bacterial Cell Sizes from the Agricultural, Domestic and Industrial Areas of Mysore District, Karnataka State, India

A two-year study on temporal variations in the ground water heterotrophic bacterial cell sizes of free living bacteria(FLB)and particle bound bacteria(PBB)from the agricultural,domestic and industrial areas was carried out from Februar y2005 to January 2007.The overall mean cell length of FLB and PBB was similar in all the ground water studied.However,the season wise grouped data revealed significant seasonal changes in cell length of FLB and PBB,as smaller bacteria were noticed during rainy season in the ground water in agricultural area in both the years,and only in the second year of study in domestic and industrial areas.Generally,it was noticed that there were summer maximum and rainy minimum values of the cell length of PBB in the ground water in agricultural,domestic and industrial areas in the second year of study.The Pearson's correlations showed the presence of 8(in agricultural area),5(in domestic)and 3(in industrial) significant correlations with environmental(Physico-chemical)parameters,respectively.The regression analysis revealed that as much as 12%of variation in the mean length of FL Bwas due to NO3( )in agricultural area and 9%due to total solids( )indomestic area.However,the 8% variation in bacterial cell size of FLB was due to Mg( )in industrial area.Whereas,13%variation in mean length of PBB was due to S04( )in agncultural area and 10%due to total anions of strong acid(TASA)( )in domestic area.Furthermore,10% of variation Was due to PO4( )in industrial area.Thus,the statistical analysis revealed that several environmental variables were potentially responsible for some of the temporal variations in aquatic heterotrophic bacterial cell size,suggesting probably the stressed environment in these ecosystems.     

Diversity and community composition of phosphorus accumulating organisms (PAOs) in the sediments of the Sanshiliujiao Lake reservoir北大核心CSCD

The diversity and community composition of phosphorus accumulating organisms (PAOs) in the sediments of the Sanshiliujiao Lake reservoir in Pingtan island, Fujian Province, were investigated by terminal restriction fragment length polymorphism (T-RFLP) methods combined with the construction of clone libraries. The diversity of PAOs in summer samples was significantly higher than that in winter. The dominant terminal restriction fragments (T-RFs) of PAOs were in the range of 200 to 300 bp in summer, while they were in the range of 150 to 200 bp in winter. Cloning sequencing and phylogenetic analysis showed that the main phyla of PAOs in the sediment of the Sanshiliujiao Lake reservoir were Proteobacteria, Actinobacteria, and Acidobacteria. Anaeromyxobacter, Azospirillum, Microlunatus phosphovorus, and Burkholderia were the dominant genera in the summer samples. Anaeromyxobacter, Methylobacterium, Solibacter, Azospirillum, and Microlunatus phosphovorus were the dominant genera in sediment samples in winter. The results of this study demonstrated that the diversity and community composition of PAOs in the sediments of the Sanshiliujiao Lake reservoir had specific seasonal characteristics. Various forms of phosphorus also showed their influence on the diversity of PAOs, especially Fe/Al-P. Our findings lays a scientific foundation for the future disclosure of microbial mechanisms involved in the phosphorus metabolic cycle in the sediments of reservoirs. © 2018 Science Press. All rights reserved.     

Environmental geochemistry studies in the area of Idrija mercury mine, Slovenia

Five centuries of mining and processing of mercury ore in the Idrija area have resulted in widespread contamination of different environmental compartments. Environmental impacts on a regional and local scale, caused by atmospheric emissions from the Idrija ore roasting plant, were established in the investigations of mercury spatial distribution in soil and attic dust in 160 km(2) area. Very high values were determined in the Idrijca River valley, and they decrease exponentially with the distance from Idrija. Mercury concentrations in attic dust are higher than in surrounding soils and the attic dust/soil ratio changes with distance. Measurements of mercury in the air confirmed widespread dispersion of mercury and showed highly elevated mercury concentrations around roasting plant and mine ventilation shaft. Beside, systematic monitoring of mercury contents in the stream sediments has demonstrated that huge amounts of mercury are stored in areas where ancient overbank sediments were deposited, and there was no decrease in mercury concentration in active sediments during the last 15 years. Recently, interesting and extremely polluted locations of historical small-scale roasting sites in the Idrija surroundings were discovered. Ongoing geochemical study aims to determine the extreme pollution and significance of these sites for wider contamination of soils and aquatic systems. Presented studies have shown that Hg mining in Idrija caused intense pollution of local and regional environment including the aquatic systems in the Gulf of Trieste, which is seen as the final sink of a major part of the Hg stored in soils and river sediments in the Idrija area.     

基于高通量分析方法的长江干流重庆段抗生素种类特征及来源初探

采用高通量分析方法对长江干流重庆段11个流域断面、2个市政污水处理厂进水和6个养殖场废水的潜在抗生素进行筛查,并结合抗生素使用调查探讨其来源。结果表明,(1)共检出83种抗生素,其中流域内检出36种,污水处理厂和养殖场废水中检出70种;磺胺间甲氧嘧啶检出率最高,在流域水体和废水的检出率分别为91%和55%,喹诺酮类是检出抗生素的主要类型;(2)长江干流重庆段下游检出抗生素数量高于上游检出抗生素;(3)有20种抗生素可能由上游携带和重庆市内排放2种方式进入流域,7种抗生素可能由上游携带入境,9种抗生素可能由重庆市内排放引入长江。     

源于大气的氟在水稻不同器官的分布及对糙米含氟量的影响

用开顶式熏气罩熏气的方法,研究了气源氟在水稻不同器官的分布及对糙米含氟量的影响。结果表明:气源氟主要分布于水稻叶片中,根含氟量不受气源氟的影响;籽粒含氟量取决于籽粒器官形成后空气氟浓度,与籽粒器官形成前的空气氟浓度无关;糙米氟含量与水稻抽穗齐穗后所暴露的氟剂量间呈极显著线性相关关系。