不同地下水位灰化薹草分解过程中木质素降解与碳、氮、磷释放的关系

为研究湿地植物分解过程中木质素分解与碳、氮、磷元素释放之间的关系及其对不同地下水位环境梯度的响应,在鄱阳湖典型碟形湖泊-白沙湖设置了200 m×300 m分解试验样地,沿地下水位梯度划分4个试验样带(从湖岸到湖心依次为GT-A, GT-B, GT-C, GT-D),采用分解袋法模拟了典型湿地植物灰化薹草在不同地下水位环境的分解过程。结果表明,分解15 d后,地下水位的升高促进了木质素的分解和碳、氮、磷元素的释放;在分解第60—90天,碳、氮、磷元素的相对归还指数随着木质素分解速率的升高而显著增大,并且相关性程度随着分解时间先增强,后减弱;分解过程中土壤pH、含水量和微生物量碳、氮对木质素的分解和碳、氮、磷元素的归还具有显著的促进作用。研究结果将有助于深化对湿地植物分解和生物地球化学循环过程的认识,为湿地自然保护区的科学有效管理提供理论依据。     

Relationship between plant cover type and soil properties on Syunkunitai coastal sand dune in eastern Hokkaido

A survey of soils and trees was conducted on Syunkunitai coastal sand dune in eastern Hokkaido to clarify the relationships between the soil properties and the plant cover type. A belt transect of 360m in length was established across the dune. Three community types, that is, a Picea glehnii forest, an Abies sachalinensis forest, and a salt marsh were recognized. Soil types at the study area were determined to be sandy immature soil and peat soil. Their horizon sequences were described as A₀–V–C or T–V–C layers (A₀, T, V, and C indicate layers of leaf litter, peat, volcanic deposit, and parent material, respectively). The Abies sachalinensis forest was characterized by a relatively high calcium concentration in the surface soil layer and a tendency for podzolization in the volcanic deposit layer. The Picea glehnii forest was characterized by peat accumulation because of the high ground water table, volcanic deposits in the soil profile, and the strong influence of sea salt on the soil chemistry. The roots in the Picea glehnii forest were distributed more shallowly than those in the Abies sachalinensis forest, thus avoiding the high water table level as well as the influence of seawater in the soil. The salt marsh showed an extremely high sodium concentration and base saturation, indicating that this area was directly affected by seawater. Recently, the periphery of the Picea glehnii forest on Syunkunitai sand dune has been declining because of seawater inundation caused by ground subsidence.     

三峡库区不同阶段蓄水前后江面江岸冬季鸟类动态

2003~2013年的隆冬季节(2011年除外),对三峡库区长江主河道的重庆朝天门港-秭归茅坪港江段(全程约618.30 km)和12条一级支流(合计调查河道长度约619.49 km),以及2个湖泊(长寿湖65.5 km~2,大洪湖30 km~2;调查年份2000~2013年,2003和2011年除外),进行了水禽及傍水栖息鸟类的监测调查。观察统计到鸟类76种,隶属8目14科39属,其中国家Ⅰ级重点保护野生动物1种,Ⅱ级重点保护野生动物3种。鉴于不同类群鸟类对环境变化的反应差别较大,将观察到的与水域生境密切相关的鸟类分为游禽类(32种)、鸥类(6种)、涉禽类(23种)、傍水栖息鸟类(13种)和空中傍水栖息鸟类[2种,以崖沙燕(Riparia riparia)为主体]等5种类型,并对各类群鸟类在三峡水库不同工程阶段蓄水高程前后的数量分布状况进行对比分析。结果显示,长江主河道中的游禽类在蓄水139 m高程前后数量波动幅度不大,蓄水156 m高程后表现出增长趋势,并且趋向于尾水点集中分布,直至最终蓄水目标175 m高程后的第5个冬季(2013年1月)数量猛增到最高,与蓄水139 m水位线前后的2个冬季(2003年1月和2004年1月)数量相比,增幅分别达171.83%和179.91%;然而2个湖泊中的游禽数值却表现出下降趋势,蓄水175 m高程后5个冬季(2008~2013年)与2000年冬季数值相比,降幅达52.96%~83.29%;大多数支流河道中的游禽数量呈现波动幅度不大或是明显下降趋势,只有乌江和小江这2条支流河道中的游禽数量呈现出增长趋势,并且小江中的游禽数量一度表现出"爆发式"增长现象后又大幅回落(2012~2013年),可能与水质富营养化程度的变化相关。涉禽类在长江主河道中的分布格局类似于游禽类(偏向于上游),其数量分别在蓄水139 m高程和156 m高程后的第1个冬季出现峰值,蓄水前后的其他年份数量差别不大;多数支流河道中涉禽类分布数量不高,只有嘉陵江、乌江、小江、大宁河与梅溪河的涉禽数量较多且数值波动明显。傍水栖息型鸟类总体数量在蓄水前后出现急剧变动,数量下降明显,个别鸟种甚至消失不见。空中傍水栖息型鸟类蓄水之后在长江主河道数量锐减,在大多数支流河道中几乎绝迹。鸥类主要分布在长江主河道,其数量在不同阶段蓄水初期出现峰值,至最终蓄水目标175 m后的第5个冬季其数量趋于接近蓄水之前。     

How to Deal with Resource Productivity

Resource productivity enhancement stands at the center of tackling issues on environmental pollution and resource scarcity. Identifying influential socioeconomic factors should be the first step in establishing and improving resource management policy. This study compares and analyzes data from multiple countries to construct a resource productivity simulation model. The socioeconomic factors and their characteristic patterns are discussed in detail. The results demonstrate that the major factors influencing resource productivity include income level, population density, economic structure, energy structure, and raw material trade. Among these factors, the three most important are income level, population density, and economic structure. The influencing patterns can be summarized as follows: (1) Resource productivity increases with increasing income levels. (2) Countries with high population density are inclined to demonstrate high resource productivity. (3) The economic structure shows a biphase influence on resource productivity, that is, during industrialization, decreased agricultural activity and increased industrial activity lead to higher resource productivity. On the other hand, after industrialization, decreasing industrial activity and an expanding service sector become the major impetus of resource productivity enhancement. (4) Raw material export demonstrates a negative effect on resource productivity. Countries that depend heavily on raw material export show a unique resource productivity evolution pattern. For these countries, relatively high resource productivity in low income phases and relatively low resource productivity in high income phases show only small increases in resource efficiency and economic growth. Finally, insights from the study are transformed into suggestions for sustainable resource management and resource productivity enhancement.     

Low-salinity transitions drive abrupt microbial response to sea-level change

The salinisation of many coastal ecosystems is underway and is expected to continue into the future because of sea-level rise and storm intensification brought about by the changing climate. However, the response of soil microbes to increasing salinity conditions within coastal environments is poorly understood, despite their importance for nutrient cascading, carbon sequestration and wider ecosystem functioning. Here, we demonstrate deterioration in the productivity of a top-tier microbial group (testate amoebae) with increasing coastal salinity, which we show to be consistent across phylogenetic groups, salinity gradients, environment types and latitude. Our results show that microbial changes occur in the very early stages of marine inundation, presaging more radical changes in soil and ecosystem function and providing an early warning of coastal salinisation that could be used to improve coastal planning and adaptation.     

食物水平和初始体重对杂交罗非鱼生长和个体生长分化的影响

将72尾杂交罗非鱼分别养在12个水槽内,每个水槽内养6尾大小不同的鱼(A、B、C、D、E、F),其中鱼A的初始体重为62．69±1．46g,B为56．48±1．30g,C为50．75±1．19g,D为35．56±1．18g,E为31．05±0．88g,F为27。35±0．95g(平均值±标准误)．在4周实验中,实验鱼分别被停食或每天按体重1．5％、3．0％和饱食水平投喂．鱼的特定生长率(SGR)和食物效率(FE)先随食物水平增加而增加,当食物水平超过鱼体重的3．0％后,继续增加投喂量,SGR不再升高而FE明显下降．按体重1．5％投喂的鱼SGR和终体重个体间变异较大．对鱼A而言,食物水平超过体重1．5％后对其SGR无显著影响,但对鱼F而言,食物水平对SGR影响较大．结果表明,杂交罗非鱼的生长和个体生长分化与食物条件和初始体重有关,当食物水平超过体重的3．0％后,鱼的SGR较高,个体生长分化相对较轻．     

全英文“环境工程微生物学”的国家线下一流本科课程成长之路

国家一流本科课程的评审认定是教育部全面深化教育教学改革的重要举措,也是提升本科教学质量的重要一环,极大地促进了任课教师对标评价量规进行教研教改。为促进环境工程专业核心基础课的教改,“环境工程微生物学”全英课程组在先进的教育思想、方法和教育心理学的指导下,对教学理念、课程内容、教学组织和实施等多方面进行了大胆的改革和创新,注重课程思政和因材施教,增加课堂教学的师生互动和生生互动;针对工科类学生的培养目标,引入实际工程的应用案例,在课内外补充环境微生物工程领域研究的最新进展和教师的科研成果,注重提升课程的高阶性、创新性和挑战度,从多方面强化知识、能力、素质的有机融合,学生学习效果明显提高。申报并获认定为首批国家线下一流本科课程和广东省一流本科课程。     

Relative sea‐level change regulates organic carbon accumulation in coastal habitats

Because coastal habitats store large amounts of organic carbon (C_org), the conservation and restoration of these habitats are considered to be important measures for mitigating global climate change. Although future sea‐level rise is predicted to change the characteristics of these habitats, its impact on their rate of C_org sequestration is highly uncertain. Here we used historical depositional records to show that relative sea‐level (RSL) changes regulated C_org accumulation rates in boreal contiguous seagrass–saltmarsh habitats. Age–depth modeling and geological and biogeochemical approaches indicated that C_org accumulation rates varied as a function of changes in depositional environments and habitat relocations. In particular, C_org accumulation rates were enhanced in subtidal seagrass meadows during times of RSL rise, which were caused by postseismic land subsidence and climate change. Our findings identify historical analogs for the future impact of RSL rise driven by global climate change on rates of C_org sequestration in coastal habitats.     

Invasion patterns in riparian habitats: The role of anthropogenic pressure in temperate streams

The riparian flora and the level of invasion in the rivers of the Cantabric watershed in Spain were studied in relation to the ecological status and the anthropogenic pressure. The level of invasion was also analyzed in different riparian habitats: forests, river bars and man-made slopes. For this purpose, 18 sites were sampled and a list of native and alien plant species was made along a 100-m strip at each site. The habitat/s where alien species were found and their abundance per habitat and in the total area were also indicated. Out of 112 alien taxa found, 51 were classified as invasive. Exotic plants native to America were the most common (35%). The level of invasion was significantly higher in the sampling sites subject to high levels of hydrological and morphological disturbances, proxies of the anthropogenic pressure. River bars and man-made slopes supported similar number of alien plant species, higher than forests. We suggest that disturbance in river banks should be minimized as much as possible in order to diminish the risk of invasion.     

Global imprint of historical connectivity on freshwater fish biodiversity

The relative importance of contemporary and historical processes is central for understanding biodiversity patterns. While several studies show that past conditions can partly explain the current biodiversity patterns, the role of history remains elusive. We reconstructed palaeo‐drainage basins under lower sea level conditions (Last Glacial Maximum) to test whether the historical connectivity between basins left an imprint on the global patterns of freshwater fish biodiversity. After controlling for contemporary and past environmental conditions, we found that palaeo‐connected basins displayed greater species richness but lower levels of endemism and beta diversity than did palaeo‐disconnected basins. Palaeo‐connected basins exhibited shallower distance decay of compositional similarity, suggesting that palaeo‐river connections favoured the exchange of fish species. Finally, we found that a longer period of palaeo‐connection resulted in lower levels of beta diversity. These findings reveal the first unambiguous results of the role played by history in explaining the global contemporary patterns of biodiversity.