新兴绿色技术——水生植物修复技术

水体富营养化治理已成为当今世界性难题,解决水体富营养化问题的关键是调控水生生态系统结构,使其恢复自然、健康和稳定的水生生态系统功能,提高水生生态系统的生物净化能力.水生植物是水生生态系统中最重要的初级生产者,在水生生态系统物质和能量循环中处于十分重要的地位.水生植物修复技术具有投资、维护和运行费用低,管理简便,处理效果好,可改善和恢复生态环境,回收资源和能源以及收获经济植物等优点,浮岛技术、人工湿地等技术也取得了显著的成就.植物修复技术作为一种绿色技术,将会有更加广阔的发展天地.     

Competitive traits of the invasive grass Arundo donax are enhanced by carbon dioxide and nitrogen enrichment

Increased atmospheric carbon dioxide (CO₂) and soil nitrogen (N) may confer competitive advantages to invasive species over native plant species. We conducted a two‐way factorial experiment, growing the model invasive plant Arundo donax in CO₂ growth chambers to test how CO₂ and N availability interact to affect plant growth and biomass allocation. CO₂ was supplied at c. 400 mg L^?1 and c. 750 mg L^?1. N was supplied as ammonium nitrate at 640, 320 and 80 mg L^?1. We hypothesised that the fertilisation effect of CO₂ enrichment would offset limitations from N deficiency. The results indicated that A. donax plants grown with enriched CO₂ and abundant N accumulated approximately 50–100% more biomass and allocated approximately 50% more biomass to rhizomes than plants grown under ambient CO₂ conditions. Neither treatment affected the leaf area per unit mass (specific leaf area; SLA). Greater growth will likely increase A. donax's competitive potential, because increased rhizome biomass has been associated with increased stress tolerance and post‐disturbance resprouting capacity. The consistent SLA under all treatments suggests that A. donax has a morphological strategy that prioritises increasing leaf quantity over increasing individual leaves' photosynthetic potential. These results reveal the ecological strategies that contribute to the successful establishment, dominance and persistence of this invasive plant species.     

若尔盖高原退化湿地土壤有机碳储量

为了定量评价若尔盖高原泥炭沼泽湿地退化的碳储存潜力,研究通过土壤剖面法,收集了3个样点的泥炭沼泽湿地土壤样品(原始泥炭地0—200cm、中度退化沼泽湿地0—100cm和重度退化泥炭地0—100cm)。研究表明:(1)中度退化沼泽湿地(1.11±0.18g/cm~3)和重度退化泥炭地(0.72±0.04g/cm~3)土壤容重平均值较原始泥炭地增加了251.8%和129.7%;中度退化沼泽湿地(46.18±6.61g/kg)和重度退化泥炭地(87.37±6.36g/kg)土壤有机碳含量平均值较原始泥炭地降低了74.2%和51.1%。(2)土层深度为0—100cm时,原始泥炭地土壤有机碳储量较中度退化沼泽湿地(384.73±95.57t/hm~2)显著高了47.0%,而与重度退化泥炭地(518.39±33.07t/hm~2)土壤有机碳储量无显著差异;当原始泥炭地有机层增加到0—200cm后,中度退化沼泽湿地和重度退化泥炭地土壤有机碳储量较原始泥炭地(1 088.17±172.84t/hm~2)降低了64.6%和52.4%,退化湿地土壤有机碳储量的降低可能主要是土壤有机碳含量降低的原因。尽管退化湿地土壤有机碳储量下降,但仍是中国(102.89t/hm~2)和全球(116.56t/hm~2)陆地土壤有机碳储量的3~5倍,该研究可为保护与恢复若尔盖高原湿地提供科学依据。     

负载型纳米零价铁(nZVI)强化垂直流人工湿地反硝化作用研究

通过在垂直流人工湿地缺氧反硝化区添加负载型纳米零价铁(n ZVI),分析不同负载型n ZVI投加量对反硝化的影响,研究不同进水C/N条件下负载型nZVI参与反硝化的效果。结果表明:投加负载型nZVI 4 g的人工湿地装置对硝氮去除效果最佳,当C/N为6、HRT=1 d、进水NO_3~--N为50 mg·L~(-1)时,其NO_3~--N去除率比未添加负载型n ZVI的人工湿地装置提高15%;随负载型n ZVI投加量的增加,人工湿地装置出水pH值和NH_4~+-N、NO_2~--N的浓度增加;在进水C/N为0、2、4、6的人工湿地装置中,其对NO_3~--N的去除率随C/N升高而升高;统计分析表明,进水C/N与负载型n ZVI投加量对人工湿地反硝化都具有显著影响,且两者具有协同作用,碳源的存在可以促进负载型nZVI参与人工湿地反硝化。     

近30年根河流域湿地景观格局变化及驱动因素分析

[目的]为了解根河流域湿地时空变化情况,明晰气候变化和土地利用变化对湿地景观格局的影响。[方法]过分析根河流域1990—2019年间的湿地范围变化,再结合期间的气候变化状况来探究流域内湿地景观格局变化的驱动因素。[结果] 30年,根河流域湿地面积减少31.89%,斑块数量增加3.74%,景观破碎度指数增加4.48,流域湿地面积总体退化显著,流域湿地斑块数量总体有所增多。1990—2004年流域湿地呈现出显著退化趋势(p<0.05),湿地面积与年降水量存在显著正相关关系,景观破碎度指数与年降水量存在显著负相关,推断年降水量是导致根河流域湿地景观格局发生显著变化的主要因素;2004—2019年流域湿地退化趋势不显著(p>0.05),年平均气温呈现出不显著上升趋势(p>0.05),景观破碎度指数与年平均气温存在显著负相关,可能是气温升高导致流域内浅层多年冻土融化而将湿地连片,降低期间湿地破碎程度。[结论]究结果对维护根河流域湿地生态系统的多样性与稳定性、促进湿地与非湿地间的协调互融性、保障湿地资源的可持续发展等具有重要的意义。     

丽江拉市海国际重要湿地生态修复方案探究

拉市海国际重要湿地是我国重要的候鸟越冬栖息地之一,针对其整体环境整治问题,地方政府和管理部门做了大量工作,取得了较好成效,但还存在退化沼泽湿地急需修复、退养鱼塘急需生态修复、入湖河道急需治理等问题,基于此,提出退化沼泽湿地、退塘还湿、入湖河段生态修复以及破碎化湖滨带治理、外来物种防控等生态修复方案。通过湿地生态修复,湿地整体生态环境得到改善,候鸟栖息地、食源地得到修复,湿地植被和生物多样性明显增加,湿地景观得到优化,湿地生态服务功能有所提高。     

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km² Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km² of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y¹. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y¹ in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y¹. The potential retention by wetlands was estimated to 57,000–145,000 ton y¹ when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y¹. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.     

湿地类型与格局对城市发展取向的制约作用

湿地是地球上独特的地理综合体和水陆复合生态系统,为城市提供了发展空间,并成为城市生态环境最重要的组成部分。城市湿地蕴涵强大的综合功能,不仅为城市发展提供重要的水资源和生态环境保障,而且城市湿地类型和格局对城市发展的取向具有重要的制约作用。湿地类型制约城市性质的形成,湿地格局制约城市景观生态结构及城市发展的取向;在对城市资源与环境的支持上,不同湿地类型的城市表现出不同特征,河流-海洋湿地融汇格局有利于城市向顶极形态发展。     

湿地与我国内陆城市的可持续发展

在我国,内陆城市的城市发展水平和经济发展水平都相对落后,因此我国内陆城市的可持续发展是关系到整个国家能否高速、健康发展的决定性因素。湿地是城市生态环境和城市生态支持系统的重要组成部分,城市中以自然景观为主的公共开放空间。本文通过对城市湿地和城市周边湿地功能作用的分析,指出湿地可以为解决我国内陆城市的生态环境问题,实现城市可持续发展,提供基础条件和生态保障。对我国生态城市的发展和建设具有借鉴意义。     

人工湿地植物应用现状与问题分析

为了在人工湿地设计与施工时更好地确定植物类型,在分析中国目前人工湿地植物的主要应用类型的基础上,提出了水生类型、湿生类型、陆生类型的人工湿地植物分类新方法。同时,对人工湿地不同植物品种和不同季节的去污效果研究进行综述,最后分析出人工湿地植物研究存在着应用的植物种类少、景观价值低、受环境影响大、二次污染、植物净化机制有待进一步加强了解的5个主要问题,并提出研究发展的3个方向。