Seasonal changes in periphyton nitrogen fixation in a protected tropical wetland

Cyanobacteria are important for global nitrogen cycle and often form complex associations referred to as cyanobacterial mats or periphyton that are common in tropical, limestone-based wetlands. The objective of this study was to monitor the nitrogen fixation rate using the acetylene reduction assay of these cyanobacterial mats in a tropical, unfertilized, and protected wetland. To account for temporal and spatial variation of nitrogenase activity, we were interested in seasons in a hydrological cycle (dry, rains, and end of rains), sites with different vascular vegetation, and rates of nitrogenase activity in a 24-h cycle. The annual average of nitrogenase activity was 22 nmol C₂H₄ cm⁻² h⁻¹, with a range of <6 to 35 nmol C₂H₄ cm⁻² h⁻¹, and the annual nitrogen fixation rate of our study site (9.0 g N m⁻² year⁻¹) is higher than similar estimates from other freshwater wetlands. There was a clear temporal pattern in nitrogenase activity with a maximum rate occurring during the rainy season (August) and a maximum nitrogenase activity occurring between 0600 and 1200 hours. We found spatial differences in nitrogenase activity among the four sites that could be attributed to variations in species composition within the periphyton.     

Methane emissions from different vegetation zones in a Qinghai-Tibetan Plateau wetland

We measured methane (CH₄) emissions in the Luanhaizi wetland, a typical alpine wetland on the Qinghai-Tibetan Plateau, China, during the plant growth season (early July to mid-September) in 2002. Our aim was to quantify the spatial and temporal variation of CH₄ flux and to elucidate key factors in this variation. Static chamber measurements of CH₄ flux were made in four vegetation zones along a gradient of water depth. There were three emergent-plant zones (Hippuris-dominated; Scirpus-dominated; and Carex-dominated) and one submerged-plant zone (Potamogeton-dominated). The smallest CH₄ flux (seasonal mean=33.1 mg CH₄ m⁻² d⁻¹) was observed in the Potamogeton-dominated zone, which occupied about 74% of the total area of the wetland. The greatest CH₄ flux (seasonal mean=214 mg CH₄ m⁻² d⁻¹) was observed in the Hippuris-dominated zone, in the second-deepest water area. CH₄ flux from three zones (excluding the Carex-dominated zone) showed a marked diurnal change and decreased dramatically under dark conditions. Light intensity had a major influence on the temporal variation in CH₄ flux, at least in three of the zones. Methane fluxes from all zones increased during the growing season with increasing aboveground biomass. CH₄ flux from the Scirpus-dominated zone was significantly lower than in the other emergent-plant zones despite the large biomass, because the root and rhizome intake ports for CH₄ transport in the dominant species were distributed in shallower and more oxidative soil than occupied in the other zones. Spatial and temporal variation in CH₄ flux from the alpine wetland was determined by the vegetation zone. Among the dominant species in each zone, there were variations in the density and biomass of shoots, gas-transport system, and root-rhizome architecture. The CH₄ flux from a typical alpine wetland on the Qinghai-Tibetan Plateau was as high as those of other boreal and alpine wetlands.     

湿地生态系统对污水中重金属的修复作用

湿地污水处理技术的研究是国内外众多学者关注的热点之一。综合国内外在污水湿地处理技术方面的研究成果,对湿地生态系统及其各组成要素对重金属污染的修复作用及其作用机理进行了讨论,针对目前利用湿地生态系统进行重金属污染废水修复过程中应注意的几个问题进行了探讨,并对今后研究发展方向进行了评述。     

旅游英语教学和实习中的秦皇岛本土文化推介

全国著名旅游城市秦皇岛有着悠久的历史和深厚丰富的本土文化底蕴,地处秦皇岛的高职院校大都开设旅游英语专业。但是在教师的教学中以及指导学生实习和实训过程中发现：学生在向中外游客宣传和推介秦皇岛的本土文化时困难重重,秦皇岛本土文化没能得到有效推介。分析了这种情况产生的原因,并提出了教学和实习改革对策。旨在使学生在涉外旅游中更好地输出秦皇岛本土文化,使高职教育更好地服务地区旅游经济发展。     

城市快速发展下大庆城市湖泊保护与发展对策

改革开放以来,大庆作为著名的石油产地,在我国经济建设中发挥了重要作用,城市建设也得到了快速的发展。然而,快速城市化也为这个有着"百湖之城"之称的城市带来了许多新的问题。针对城市快速发展之下,大庆城市湖泊现状进行分析,提出大庆城市湖泊保护与利用的对策。     

浅谈湖南湿地生态功能及作用

指出了湿地作为一种重要的自然资源,拥有丰富的生物多样性,具有巨大的生态功能和效益。总结了湖南省湿地污染物净化与过滤、调节气候、蓄水、调节径流、均化洪水、提供动植物栖息地以及维持区域生态平衡等生态功能,分析了湿地对湖南建设的作用。     

白洋淀湖心岛分散式鸭养殖污染控制技术研究

白洋淀分散鸭养殖产生的污染物是导致其水体污染的主要来源之一。依据“减量化、就地处置资源化、养分循环”思路,提出湖心岛分散鸭养殖污染控制模式,主要包括：鸭粪收集系统（收集网、径流和冲洗水收集沟）、鸭粪沼气发酵与利用系统、沼液湿地净化和沼渣利用系统。选择安新县安新镇王家寨村占地5 000 m2养殖1 500只鸭的湖心岛建立综合控制示范工程。2010年4~11月,示范工程在典型降雨日和非降雨日排水的COD、总氮、总磷分别为351 mg/L、74.2 mg/L、7.1 mg/L和214 mg/L、42.1 mg/L、5.3 mg/L,水质符合《畜禽养殖业污染物排放标准》（GB 18596-2001）；这是由于源头收集系统收集了陆上活动区40%的鸭粪,同时末端处理系统（沉淀池+人工湿地）对养鸭废水污染物的高效削减。沼气池产生的沼气和剩余的沼液沼渣可以作为能源和肥料加以利用。本文集成湖心岛分散鸭养殖污染控制模式简便、适用,具有推广价值。     

人工湿地法解决五岳河水污染问题的可行性

人工湿地作为一种污水生物处理技术,因其具有独特的优势,已得到广泛的应用。针对五岳河水污染现状,结合人工湿地处理废水的特点,从场地选择、工艺类型选择等方面论述利用人工湿地法解决五岳河水污染问题的可行性。     

生态与景观的理性融合——湖州长田漾湿地公园概念性规划

以湖州长田漾湿地公园概念性规划为例,探讨在规划中运用景观生态学相关理念构建良好的区域生态格局、采用生态技术恢复和营造湿地景观、通过生态手法恢复地方性植被和挖掘乡土素材构建乡土景观等,实现科学保护与合理利用湿地,生态与社会价值并举的规划思路。     

千岛湖国家重要湿地非生物资源及其利用调查

2009年10月～2011年10月,对千岛湖国家重要湿地非生物资源及其利用状况进行了调查.千岛湖湿地非生物资源有水资源、旅游资源、湿地岛屿和土地资源等,湿地蓄水总量178.4×108 m3,整体水质良好,全湖富营养化程度较稳定；旅游资源有8主类23亚类181种基本类型238个旅游资源单体,其中优良级旅游资源单体29个；湿地岛屿总面积5 954.53 hm2,其中林地面积5 913.80 hm2,非林地面积40.73 hm2;库尾和库湾季节性可耕地面积随水位变化在192.1 ～1 013.8 hm2间变化,千岛湖湿地非生物资源利用主要是水资源和旅游资源,湿地旅游已发展成为淳安县的经济支柱产业.