寒旱区湖泊冰封期有机碳氮同位素研究

为了探究寒旱区湖泊悬浮物和沉积物中颗粒有机碳氮稳定同位素来源与环境相关性,于2019年1月对南海湖冰封期悬浮物和表层沉积物有机δ¹³C、δ¹⁵N及C/N值进行了测定.结果表明：南海湖冰封期悬浮有机质δ¹³C的变化范围为-31.94‰~-27.87‰,δ¹⁵N变化范围为15.16‰~18.66‰,C/N变化范围为3.90~5.13.沉积物δ¹³C值变化范围为-25.39‰~-18.83‰,δ¹⁵N值变化范围为7.04‰~13.66‰,C/N值变化范围为7.66~12.23.悬浮有机质δ¹³C和δ¹⁵N最高值分别出现在进水口区和湖心岛区,沉积物则都为湖心岛区表层沉积物.端元混合模型分析表明,冰封期悬浮有机质主要由内源水生藻类主导,水质保护区藻类贡献率达到82.33%,与该区域浮游植物丰度最高相符.表层沉积物有机质的主要来源为内源水生植物,在水质保护区贡献率高达89.7%.相关性分析表明,在冰封期内悬浮有机质与表层沉积物δ¹³C、δ¹⁵N并没有明显的相关性,在低温情况下悬浮物δ¹⁵N与温度（P<0.025）、硝态氮（P<0.019）呈显著负相关,与亚硝态氮呈显著正相关（P<0.034）.原因主要与外源贡献率和生物作用的同位素效应有关.悬浮物δ¹³C和COD呈极显著正相关（P<0.008）,与盐度呈显著正相关（P<0.046）,COD和悬浮物δ¹³C很可能具有同源性,在湖泊冰封期具有一定的环境指示意义.     

嘉陵江出口段水体碱性磷酸酶活性特征

于2011~2016年间,从嘉陵江重庆主城段水域的"磷营养状态-总碱性磷酸酶活性变化-藻华"之间的相关关系入手,通过原位实验总结TAPA与ALGAE及SRP变化规律,结合碱性磷酸酶反应动力学实验确定酶活参数,探讨酶活变化在"藻华"中的生态学意义.结果表明：消落期时,SRP为藻类生长活动主要的磷源."藻华"敏感期SRP含量全年最低,为0.012~0.021mg/L;TAPA全年最高,为10.503~11.587nmol/（L·min）.特征参数V_m和米氏常数K_m值的变化规律验证了"藻华"敏感期各样点碱性磷酸酶对底物的亲合力增高,酶的水解速率有了显著提升;碱性磷酸酶在其他形态的磷转化为SRP的过程中有很大的促进作用,为藻类等微生物生长提供充足的SRP,以利于其在适宜的生境中迅速增殖.     

农业文化遗产地有机生产转换期农产品价格补偿测算——以云南省红河县哈尼梯田稻作系统为例

高效农业技术广泛使用提高了农业生产效率,促进了粮食产量增长,但同时也带来环境问题、食品安全问题和传统农业文化逐渐消失等负面效应。哈尼梯田作为全球重要农业文化遗产(GIAHS),具有生态价值、农业生产价值和景观价值等多重价值,保护哈尼梯田农业系统意义重大。通过有机生产提高稻谷价格的方式,推动农民继续种植水稻,可以达到保护哈尼梯田农业系统的目的。然而,从非有机到有机生产有一个转换期,这期间稻谷无法以有机产品的价格出售,所以,政府须给予一定的价格补偿才可保证农民利益和生产的持续性。论文采用问卷和访谈等调查方法,获取哈尼梯田地区农户有机转换期种植投入产出状况和劳动力外出务工收入状况,以及现代规模生产方式下的投入产出状况,通过分析对比和核算,得到结果如下:1哈尼梯田地区有机转换期水稻种植直接投入高于现代水稻种植方式,总投入成本中劳动力成本占比最大,而单产低于现代水稻种植方式;2哈尼梯田地区的青壮年劳动力偏向于在城市生活和务工,外出务工收入明显高于常规农业收入,使农业机会成本较高;3有机转换期的稻谷价格补偿至少2.84元/kg才可保证有机转换期农民收入稳定,从而达到保护哈尼梯田景观的目的。     

季节性温度升高对落干期消落带土壤氮矿化影响

为揭示季节性温度升高对消落带落干期土壤氮矿化的影响,分别采集三峡支流澎溪河消落带上游和下游两个水文断面,155 m(低)、165 m(中)和175 m(高)这3个水位高程表层土壤,结合落干期气温变化特点,在25℃和35℃两个温度下进行恒温培养.结果表明,消落带土壤总氮和硝态氮在上游断面和高水位高程含量更高,而下游和低水位高程含量更低,铵态氮分布与其相反.硝态氮是无机氮的主要存在形式,占无机氮的57.4%~84.7%.相同培养温度下,氨化、硝化、净氮矿化速率均表现为随水位高程增加,随流域断面由下至上而显著增加(P0.05);总体上,在水位高程和流域断面上均表现为:温度升高使硝化速率和净氮矿化速率显著增加(P0.05),而对土壤氨化速率无显著影响(P0.05).     

Dynamics of bacterial community of Suillus granulatus mushroom shiro in Pine (Pinus tabuliformis) forests北大核心CSCD

To evaluate bacterial community variation in the mushroom shiro of Suillus granulatus during fruiting, we collected soil samples from the mushroom shiro in the pine (Pinus tabuliformis) forest of mountainous area in Beijing from May to November and evaluated the bacterial community using polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE). Total soil DNA was extracted using a commercial soil DNA isolation kit. PCR amplification and DGGE were performed using bacterial universal primers 338F and 518R. The specific bands were excised from the gel and sequenced. The results revealed that soil bacterial community maintained considerably high level and changed seasonally with the mushroom fruiting. In total, 53 bands of DGGE profiles were sequenced and divided into 5 phyla (Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria and 22 genera (Acidobacterium, Aminobacter, et al). Species from Proteobacteria and Acidobacteria were the dominant bacterial groups sharing considerably high relative abundance, while class a-Proteobacteria was the most abundant group. The variation of the relative abundance of γ-Proteobacteria species was consistent with the mushroom fruiting season. The relative abundance of Acidobacteria species obviously increased before mushroom flush (in July). The fruiting of S. granulatus and the relative abundance of γ-Proteobacteria were correlated with each other. The present study provided a basis for conservation and domestication of mushroom S. granulatus.     

西南技术工程研究所, 重庆 400039

目的建立敦煌地区温度、相对湿度和日温差的年极值拟合模型。方法根据当地气象站台温度和相对湿度日记时值数据,连续统计若干年的三要素年极值,采用极大似然法建立各要素年极值的Gumbel模型,同时讨论值域有界类气象因素极值再现期的定义域。结果给出了敦煌地区温度、相对湿度和日温差年极值的Gumbel模型参数。结论敦煌地区各气象因素Gumbel模型位置参数和尺度参数,温度极大值分别为35.193,1.072℃,温度极小值分别为-20.085,1.945℃,相对湿度极大值为95.254%,2.471%,相对湿度极小值为5.837%,1.505%,日温差极大值为20.676,0.777℃,日温差极小值为1.398,0.593℃;相对湿度极大值、相对湿度极小值和日温差极小值的再现期定义域分别为6.3,47和10年。     

线性拟合法评定水中砷的测量不确定度研究

测量不确定度是评定测量值分散程度的一项指标,对解释测量结果非常重要,对于一个分析方法若未进行不确定度评估,则无法确定测量结果间观测到的差值是否包含试验变异以外的信息,没有不确定度的信息,就存在错误处理结果的风险,甚至导致不必要的损失,不给出不确定度的测量数据是没有意义的数据.线性拟合法利用从方法确认、实验室内质控和实验室间协作定值等数据,注重从整体上、通过数月、数年等一段期间反映样品检测精密度数据直接评估测量不确定度.     

Copula-Based Bivariate Return Period Analysis and Its Implication to Hydrological Design Event

In univariate frequency analysis, the return period of an event has a one-to-one correspondence with its characteristic value, and the response of the hydraulic structure to hydrological load expressed by the hydrological event is monotonic. Thus, the design criteria of the hydraulic structure can be equivalently represented by the return period of the hydrological event, and consequently, design event-based design parameters evaluated have been widely used in practical engineering. However, the monotonic correspondence between the return period of the hydrological event and the response of the hydraulic structure does not exist in the multivariate context, and hydrological load with a larger joint return period does not always produce a more unsafe response. Misunderstandings of concepts of return periods of hydrological event, and estimation of hydrological design events usually take place in multivariate frequency analysis. This study theoretically derives the relations between different types of joint return periods, joint return period and its marginal return periods, the occurrence of bivariate extreme events and their return periods, and then the theoretical framework is tested. Results from the case contribute to the understanding of bivariate return periods of hydrological event, and the results demonstrate that design criteria cannot be equivalently represented by joint return periods of hydrological load, and design parameters of the hydraulic structure should not be determined by multivariate hydrological design events.     

人机操作界面中有或无外部反应对后继作业的干扰作用

实验结果提示：在高速复杂人机系统操作界面的优化设计中,有或无外部反应都不能消除对后继作业的瓶颈干扰。但是,有外部反应比无外部反应,对后继作业的瓶颈干扰更大;无外部反应降低了瓶颈的干扰强度,从而显示出提高了被交叠作业绩效的趋向。另外,降低反应选择复杂度可有效提高被交叠作业的绩效