苏北海域表层沉积物中PH3的分布

为研究海洋生态系统中PH3的迁移转化规律及其产生机制,2006年12月对苏北海域表层沉积物中磷化氢(PH3)、总磷(TP)、无机磷(IP)、有机磷(OP)及有机质(OM)的分布进行了系统分析和讨论。结果表明,PH3在苏北海域表层沉积物中普遍存在,含量在[(2.63±0.38)~(39.35±5.49)]×10-12之间,最大值出现在长江口,最小值出现在辐射沙洲海域。辐射沙洲海域TP和IP的含量较低,长江口及吕四一带含量相对较高,且沿着长江入海方向逐渐减少。OP和OM分布的总体趋势是由南至北,由西到东含量逐渐减小,长江口及吕四港一带含量较高。区与区间PH3与TP、IP及OP的相关性分析表明,IP作为PH3的生成前体物可能性比OP高。     

Carbon sequestration via afforestation as a sustainable action to mitigate climate change in Western Iran

Climate change involves increasing atmospheric carbon dioxide concentration which is driven by anthropogenic emissions. Afforestation, which is the establishment of forests on previously non‐forested lands, could be a suitable climate change mitigation strategy. The aim of this research is to evaluate the carbon sequestration capability of the Eucalyptus and Prosopis species in the Reza‐Abad afforestation park in western Iran. For this aim, three stands of any species were selected. For quantitative assessment, a transect was implemented at the length of 100 m. In trees located of transects, the general characteristics of species were measured. Also, for estimating the amount of litter, a sample plot has been measured at the center of the quadrate. These samples were taken from the afforested area, the control area inside the afforested area and another control area outside. In each stand, species were selected randomly and one‐eighth of the whole stand was taken for calculating the percentage of carbon and aerial biomass. Then the aboveground organs were weighted and after the transfer of different plant organs to the laboratory, the conversion factor of carbon sequestration of the plant organs was determined individually by combustion method. Also, soil samples were also collected from two depths of 0–15 and 15–30 cm in each of the cultivated and control parts. The results showed that there is a significant difference between the species and Prosopis has higher carbon sequestration than Eucalyptus. The carbon sequestration among different organs showed a significant difference, carbon sequestration was 19.24 t/ha for Eucalyptus and 18.43 t/ha for Prosopis. After an economic calculation, it was concluded that afforestation has a positive effect on the reduction of atmospheric carbon dioxide. Hence, these results allow decision makers to change land use from desert area to forest, and planting the Prosopis species is more recommendable than Eucalyptus for afforestation in such areas which are economically profitable.     

Influence of different weather events on concentrations of particulate matter with different sizes in Lanzhou, China

The formation and development of weather events has a great impact on the diffusion, accumulation and transport of air pollutants, and causes great changes in the particulate pollution level. It is very important to study their influence on particulate pollution. Lanzhou is one of the most particulate-polluted cities in China and even in the world. Particulate matter (PM) including TSP, PM_>10, PM_2.5-10, PM_2.5 and PM_1.0 concentrations were simultaneously measured during 2005-2007 in Lanzhou to evaluate the influence of three kinds of weather events - dust, precipitation and cold front - on the concentrations of PM with different sizes and detect the temporal evolution. The main results are as follows: (1) the PM pollution in Lanzhou during dust events was very heavy and the rate of increase in the concentration of PM_2.5-10 was the highest of the five kinds of particles. During dust-storm events, the highest peaks of the concentrations of fine particles (PM_2.5 and PM_1.0) occurred 3 hr later than those of coarse particles (PM_>10 and PM_2.5-10). (2) The major effect of precipitation events on PM is wet scavenging. The scavenging rates of particles were closely associated with the kinds of precipitation events. The scavenging rates of TSP, PM_>10 and PM_2.5-10 by convective precipitation were several times as high as those caused by frontal precipitation for the same precipitation amount, the reason being the different formation mechanism and precipitation characteristics of the two kinds of precipitation. Moreover, there exists a limiting value for the scavenging rates of particles by precipitation. (3) The major effect of cold-front events on particles is clearance. However, during cold-front passages, the PM concentrations could sometimes rise first and decrease afterwards, which is the critical difference in the influence of cold fronts on the concentrations of particulate pollutants vs. gaseous pollutants.     

不同价态铁处理腈纶废水过程中菌群结构分析

利用不同反应器条件（SBBR、Fe （0）-SBBR、Fe （Ⅱ）-SBBR、Fe （Ⅲ）-SBBR）对腈纶废水进行处理,探究不同价态铁对腈纶废水处理过程及此过程中微生物群落结构变化.结果表明,Fe （0）/Fe （Ⅱ）/Fe （Ⅲ）-SBBR对腈纶废水有良好的处理效果,特别是NH₄⁺-N,去除率均在90%以上;整个运行周期内Fe （0）-SBBR处理效果最好.利用Illumina MiSeq高通量测序技术分析处理过程中微生物群落结构,结果表明,Fe （0）/Fe （Ⅱ）/Fe （Ⅲ）-SBBR优势菌在属水平上差异显著,Fe （0）-SBBR主要以Gemmata、Planctomyces、Aridibacter、Fluviicola等属为主;Fe （Ⅱ）-SBBR主要以Thermomonas、Aridibacter、Bacillus、Paracoccus等属为主;Fe （Ⅲ）-SBBR主要以Planctomyces、Bacillus、Nostocoida、Aridibacter等属为主;与对照组SBBR相比,Fe （0）-SBBR对其处于相对劣势的菌有很好的刺激生长作用;Fe （0）和Fe （Ⅲ）对微生物群落的改变大于Fe （Ⅱ）.     

不同干扰强度下三江平原湿地土壤温室气体排放对冻融作用的响应

为评估季节性冻融作用对不同干扰强度湿地温室气体产生机制的影响,采用静态箱/气相色谱法,原位观测三江平原洪河国家自然保护区内未受干扰的常年积水的小叶章湿地(undisturbed Deyeuxia angustifolia wetland,UDAW)、保护区外受人类活动干扰导致湿地含水量减少的季节性积水的小叶章湿地(disturbed Deyeuxia angustifolia wetland,DDAW)以及由小叶章湿地开垦10年以上的水稻田(rice paddy,RP)的温室气体排放通量,分析季节性冻融作用对3种湿地温室气体排放的影响特征.结果表明:3种湿地在冻融期均有CO₂和CH₄排放,且在春季冻融初期CO₂和CH₄均出现短期的高排放现象,随着冻融温度升高,温室气体排放通量均逐渐增加.其中,CO₂排放通量表现为UDAW > DDAW > RP,CH₄排放通量却表现为DDAW > RP > UDAW;DDAW的CH₄排放速率与冻融温度的相关性最高(P < 0.01,R2=0.647 5),UDAW中二者的相关性最低(P < 0.01,R2=0.424 7).相关性分析显示,DDAW和RP土壤中CO₂与CH₄的排放通量均呈正相关(P均小于0.01,R2分别为0.749 1、0.574 4),而UDAW土壤中CO₂与CH₄的排放通量表现为弱相关(P < 0.05,R2=0.303 8),可见冻融温度会影响CO₂和CH₄的排放通量.季节性冻融作用影响了3种湿地土壤N₂O的排放通量,秋季冻融期UDAW和DDAW表现为N₂O的汇,而在春季冻融期3种湿地均表现为N₂O的源,表明不同干扰湿地N₂O的排放通量对冻融作用的响应不同,但均随土壤温度的升高其排放通量不断增加.研究显示,三江平原的冻融作用降低了湿地温室气体排放,干扰强度越大,冻融作用影响越小,且秋季冻融作用大于春季.      

利用电石渣制备多种晶形碳酸钙的研究

为了有效地利用电石渣资源,研究用电石渣为原料制备球形、板状形、针叶形碳酸钙.利用DTA-TG、SEM等研究了电石渣的预处理方式对碳酸钙纯度的影响和碳化反应温度、CO₂流量等对多晶型碳酸钙形成的影响.结果表明:电石渣可直接与氯化铵反应,当pH>7时,合成的碳酸钙的纯度大于97%,白度大于98.电石渣经过处理后,在不同的碳化反应温度及合适的CO₂流量的条件下分别可以得到球形、板状形、针叶形的碳酸钙.     

城市空气质量监测网络评估方法

通过研究借鉴多个国家/城市的研究实践,提出了城市空气治理监测网络（UAAMNA）评估管理的方法,包括评估思路与流程,评估关键指标,针对不同污染物的评估方法等.以沈阳市及周边6个城市共46个国控监测站点的监测网络为背景,基于2013~2018年日尺度空气质量数据,考虑监测成本,对沈阳市PM_2.5监测网络进行评估,结果表明,沈河区增加1个最高浓度站点,大东区增加1个高人口密度区站点,皇姑区增加1个跨界传输点;在沈阳-铁岭,沈阳-本溪,沈阳-辽阳方向增设跨区域站点.未来建立空气质量监测网络定期评估制度、加强跨区域边界站点布设、实施区分监测点位类型评估、区分污染物类型评估是UAAMN的发展方向.     

重金属含量对城市土壤真菌群落结构的影响

作为土壤微生物系统的一个重要组成部分,真菌可以明显地对土壤环境的变化起到指示作用;城市中的人为活动很容易影响到土壤状况,因此城市土壤往往有人为重金属富集现象的出现.对城市内部不同功能区土壤中的真菌群落结构进行分析,旨在探明城市内部不同功能区中重金属含量对土壤真菌群落结构的影响,为城市土壤生态系统的修复与保护和城市环境质...     

太湖不同营养水平湖区汞的形态和分布特征

为研究富营养化对太湖汞形态分布特征的影响,于2011年水华暴发期,在太湖不同营养水平湖区(竺山湾、贡湖湾及南太湖)采集水样,测定了水体中THg(总汞)、DHg(溶解态总汞)、RHg(活性汞)、TMeHg(总甲基汞)、DMeHg(溶解态甲基汞)的质量浓度及其分布特征. 结果表明,太湖不同营养水平湖区水体中ρ(THg)和ρ(DHg)无显著差异,ρ(THg)为4.67~12.15 ng/L,ρ(DHg)为2.27~10.36 ng/L. 太湖水体中ρ(RHg)平均值为0.79 ng/L,藻类的生长对水体中ρ(RHg)的分布有显著影响,水体营养水平越高,ρ(RHg)越低. 水体中ρ(TMeHg)和ρ(DMeHg)分别为0.10~0.27和0.09~0.23 ng/L,藻类的吸附及水体中较高的E_h(氧化还原电位)和pH抑制了汞的甲基化,但在富营养化较严重的竺山湾,受藻类生长及水华的影响,水体中ρ(TMeHg)(0.22 ng/L)仍相对较高.      

不同封育年限荒漠草原土壤呼吸日、季动态变化及其影响因子

围封禁牧措施可以改善退化草地生态环境,是我国退化草地植被恢复的主要措施.为探讨干旱区荒漠草原不同围封禁牧年限的土壤呼吸作用特征及影响因子,在生长季连续观测围封禁牧11 a、7 a、放牧不封育(CK)荒漠草原土壤呼吸速率及环境因子,结果表明:1在日、季尺度上,封育11 a、7 a和CK荒漠草原土壤呼吸速率均具有明显的单峰曲线变化规律,在日尺度上,最大、最小值分别出现在12:00~16:00和00:00~06:00;在季节变化尺度上,最大值出现在降水较多温度适宜的8月,土壤呼吸均值表现为11 a[0.143 g·(m2·h)-1]7 a[0.138 g·(m2·h)-1]CK[0.106 g·(m2·h)-1].2封育与未封育荒漠草原的土壤呼吸速率与空气、土壤温度均呈极显著的指数关系(P0.001),相关性大小为:地表温度(R2:0.408~0.413)空气温度(R2:0.355~0.376)5~20 cm土壤温度(R2:0.263~0.394);温度敏感性系数Q10随着土层的加深逐渐变大,不同封育年限Q10表现为11 a(2.728)7 a(2.436)CK(2.086).3封育11 a、7 a和CK荒漠草原土壤呼吸速率与空气湿度、土壤含水量一元二次模型达到显著水平(P0.05),与空气二氧化碳呈极显著线性负相关(P0.01),与风速呈显著线性正相关(P0.05),与光照强度呈极显著线性正相关(P0.01).4干旱区荒漠草原土壤呼吸作用随着围封禁牧年限的增加而增加,温度敏感性系数亦随之增加,0~20 cm土壤温度和水分是其土壤呼吸的主要影响因子.