Seasonal dynamics of phytoplankton and its relationship with the environmental factors in Dongping Lake, China

Dongping Lake is the final adjusting and storing lake in the east route of the South-to-North Water Diversion Project in China, and there has been serious concern regarding the water quality. Understanding the process of phytoplankton variation can be particularly useful in water quality improvement and management decisions. In this study, the phytoplankton taxonomic composition, abundance, temporal variations, spatial distribution, and diversity were studied based on a monthly sampling campaign from three sampling stations between May 2010 and May 2011. A total of 132 species (8 phyla, 72 genera), including 64 species of Chlorophyta, 26 species of Bacillariophyta, 21 species of Cyanophyta, 12 species of Euglenophyta, 3 species of Cryptophyta, 2 species of Xanthophyta, 1 species of Pyrrophyta, and 3 species of Chrysophyta were identified. Average phytoplankton diversity index and evenness values were 3.83 and 0.77, respectively, revealing a high biodiversity of phytoplankton community. The phytoplankton abundance averaged 5.11?×?10⁶ cells/L, with Bacillariophyta dominant in winter and spring, but Cyanophyta in summer and autumn. There were 14 predominant species including Pseudanabaena limnetica, Chlamydomonas simplex, Cyclotella stelligera, and Chroomonas acuta. Phytoplankton community structure and water quality variables changed substantially over the survey period; redundancy analysis, Pearson correlations, and regression analysis as an integrated approach were applied to analyze the relationships among them. Total phosphorus and ammonium played governing roles in the phytoplankton dynamics of Dongping Lake during all periods investigated.     

Bioavailable phosphorus transport from a hillslope cropland of purple soil under natural and simulated rainfall

To further understand the mechanism of bioavailable total P (BAP) and bioavailable dissolved P (BDP) transport by overland and subsurface flow, we exposed a runoff plot 4.5 m long × 1.5 m wide × 0.6 m deep to simulated and natural rainfall in order to study the effects of rainfall type, rainfall intensity, and vegetation cover on BAP and BDP transport. The results showed that vegetation cover could alleviate the discharge of overland flow and sediment transport and enhance subsurface flow. BAP transport significantly increased with elevated rainfall intensity. Vegetation cover reduced the BAP transport by overland flow and increased it by subsurface flow. BDP transport showed no significant relationship with vegetation cover and rainfall type. The bioavailable particulate P (BPP) transport by overland flow contributed to no less than 90% by weight of total BAP, and the BPP transport by subsurface flow contributed to no less than 60% by weight of total BAP. Short-time heavy rainfall caused more BAP transport and accelerated non-point source pollution.     

经济转型背景下工业污染时空格局演变及其驱动因素研究——以长江三角洲地区为例

合力打好污染防治攻坚战、强化区域生态环境共保是全面贯彻落实绿色发展理念,推动长三角地区更高质量一体化发展的重要内容。在中国区域经济转型发展背景下,利用城市工业污染物排放和经济社会发展统计数据,重点分析了2003～2015年长三角地区主要工业污染物排放相对规模和强度的时空格局演变规律,探讨了经济转型发展等因素对工业污染时空格局的动态影响机制。研究结果表明:(1)长三角地区主要工业污染物排放相对规模和强度总体呈下降趋势,2003～2015年工业废水、SO_2排放总量分别削减约13%和24%,每万亿元工业总产值的废水、SO_2和烟(粉)尘排放量分别削减87%、88%和71%左右。(2)工业污染排放仍主要集聚在沿沪宁、沿长江和沿沪杭甬等工业发达地区以及部分资源型城市,并呈现由核心区向皖江城市带、苏北等外围区转移扩散的态势,但不同污染物之间差异较为显著。(3)外围区工业污染物排放相对强度较高(多为1.0以上),但近年来南京、杭州等核心区的工业污染物(尤其是工业粉尘)排放相对强度有所上升。(4)经济转型是工业污染时空格局演变的重要驱动力,其中产业结构升级、创新与消费驱动转型增长等是抑制工业污染物排放规模扩张的重要因素;而创新投入及技术进步、企业质效提升、外资外贸结构优化等则有利于降低工业污染物排放相对强度;但由于各地经济转型阶段不同,上述因素对工业污染的影响机制存在显著的空间差异。该研究揭示了经济转型背景下工业污染时空格局演变及驱动因素,对于强化新时期长三角地区工业污染协同防治等具有一定政策参考价值。     

表面处理技术在给排水管道防腐中的应用现状探究

给排水管道是市政排水工程当中不可或缺的重要内容,其质量直接影响着我国当前广大群众们的日常生活质量。随着我国当前城镇化进程迅速发展,广大群众们对自身生活质量要求也日渐增大。给排水管道在建筑当中的投入使用,直接影响着当前广大群众们自身的生活水平和生活质量。本文针对给排水管道出现腐蚀问题的成因进行详细分析,其目的是研究出表面处理技术在给排水管道防腐中的应用途径。     

用于风力发电的测风系统对比研究

介绍了机械式测风传感器与超声波测风传感器的工作原理,比较了它们的特点,及对风力发电的影响。分别对装有2类测风传感器的风力发电机组进行了运行分析,得出2类测风传感器对应的机组功率曲线增长率。试验结果表明:超声波测风传感器进行风速、风向测量更有利于提高风力发电机组的利用率与稳定性。     

循环经济的理论依据研究

循环经济的发展是按照一定的客观规律运行的,研究循环经济的理论依据就是研究其客观运行规律。循环经济的理论依据大体分物理学理论、生态学理论、系统科学理论和区域科学理论等4个方面,其对循环经济的发展有一定的实践指导意义。     

基于空间场效应的陕西入境旅游流空间转移特征研究

选取不同时间断面的陕西与中国五大典型旅游区入境旅游流相互转移的有关数据和利用空间场效应理论对陕西入境旅游流空间场进行场能、位势及地域结构分析,研究其空间聚集效应、扩散效应和场效应交互作用影响下的旅游流时空转移规律及空间分布特征。结果表明,陕西入境旅游流空间场集聚效应强于扩散效应,且呈增强趋势;陕西与东部旅游区转移量大,与西部旅游区转移概率大,因此东部地区仍是陕西跨区域旅游合作的重点地域,而西部地区则是陕西加强旅游合作与建设的重要地区。     

2000-2008年青海省居民生活能源消费与碳排放分析

本文根据与青海省城乡居民生活能源消费相关的8个部门的能源消费数据,采用统计分析方法,从最终需求的角度评估了2000-2008年城乡居民生活能源消费及其碳排放。研究发现2000-2008年青海省城镇与农村居民生活用能在总量和人均水平上均相差很大,并且由此产生的碳排放是城镇居民远高于农村居民,其中,城镇居民生活用能主要集中在食品、娱乐教育文化服务、衣着3个部门,占总能源消费的61.02%,而农村居民生活用能主要集中在食品、居住和交通通讯3个部门,占总能源消费的71.77%。如果青海省农村居民能源消费水平达到青海省城镇居民能源消费的最低水平,会引起能源消费量及碳排量的急剧增加。     

基于旅游体验学基本范畴的旅游节庆发展研究

本文运用旅游体验学基本范畴理论揭示了旅游节庆与旅游体验学基本范畴的特征关系,在此基础上构建了旅游节庆可持续发展的基本模型,从重构惯常生活世界、营造旅游世界和旅游活动设计注重社区居民与旅游者互动三个方面提出了旅游节庆发展的新思路与方法。