碳达峰碳中和目标下自然资源管理领域的关键问题

基于低碳目标创新自然资源管理体制,对于提升生态系统碳汇水平和自然资源支撑能力,推动经济社会中长期低碳转型具有重要意义。围绕“双碳”目标下的自然资源管理,九位专家分别从不同视角提出了创新自然资源管理的策略,为基于“资源要素—国土空间—生态系统”多层次视角构建低碳导向的自然资源管理体制提供参考借鉴。专家认为：未来应构建“双碳”目标下自然资源管理领域的系统性应对框架,建立健全自然资源“要素—空间—系统”多层次协同管理的体制机制;构建全域自然资源及国土空间碳循环监测网络和符合中国国情的碳核算标准体系,探索差别化国土空间管控方案;加强“自然—经济—社会”复合系统的资源流通管理,探寻基于资源优化管理的区域协同碳减排路径;将碳汇价值纳入碳交易和生态补偿体系,构建基于国土空间碳中和评价的区域横向碳补偿制度,推动区域协同减排和公平协调发展。     

Fine particulate matter (PM2.5/PM1.0) in Beijing, China: Variations and chemical compositions as well as sources

Particulate matter (i.e., PM_1.0 and PM_2.5), considered as the key atmospheric pollutants, exerts negative effects on visibility, global climate, and human health by associated chemical compositions. However, our understanding of PM and its chemical compositions in Beijing under the current atmospheric environment is still not complete after witnessing marked alleviation during 2013–2017. Continuous measurements can be crucial for further air quality improvement by better characterizing PM pollution and chemical compositions in Beijing. Here, we conducted simultaneous measurements on PM in Beijing during 2018–2019. Results indicate that annual mean PM_1.0 and PM_2.5 concentrations were 35.49 ± 18.61 µg/m³ and 66.58 ± 60.17 µg/m³, showing a positive response to emission controls. The contribution of sulfate, nitrate, and ammonium (SNA) played an enhanced role with elevated PM loading and acted as the main contributors to pollution episodes. Discrepancies observed among chemical species between PM_1.0 and PM_2.5 in spring suggest that sand particles trend to accumulate in the range of 1–2.5 µm. Pollution episodes occurred accompanied with southerly clusters and high formation of SNA by heterogeneous reactions in summer and winter, respectively. Results from positive matrix factorization (PMF) combined with potential source contribution function (PSCF) models showed that potential areas were seasonal dependent, secondary and vehicular sources became much more important compared with previous studies in Beijing. Our study presented a continuous investigation on PM and sources origins in Beijing, which provides a better understanding for further emission control as well as a reference for other cities in developing countries.     

草原生态补奖政策对农牧民牲畜养殖规模的影响——基于生计分化的调节效应分析

实现对牲畜养殖规模的有效管控是草原生态补奖政策成败的关键。在农牧民生计分化日益加深的背景下,探讨草原生态补奖政策与生计分化对农牧民牲畜养殖规模的影响,对于完善草原生态补奖政策,实现草原生态保护与农牧民生计转换的有机结合具有重要的现实意义。本文阐释了草原生态补奖政策影响农牧民牲畜养殖规模的机理,并引入生计分化变量,基于实地调研获取的317份农牧交错区农牧民微观数据,运用最小二乘回归和分位数回归实证分析了草原生态补奖政策对农牧民牲畜养殖规模的影响以及生计分化在草原生态补奖政策影响农牧民牲畜养殖规模中的调节效应。研究结果表明:①补奖金额与牲畜养殖规模之间存在稳健的“倒U型”关系,表明补奖政策在短期内对牲畜数量的增加具有积极的促进作用,但随着补奖金额的增加,促进作用将逐渐减弱,最终趋于抑制。②根据非农牧收入占比和生计对牧业生产依赖程度的差异可将农牧民分为牧业为主型、农业为主型、均衡型、高兼型和深兼型五种类型农牧民。③农牧民生计分化对牲畜养殖规模的扩大具有抑制作用,且在草原生态补奖政策与牲畜养殖规模二者关系中具有调节作用。即在“倒U型”曲线的左侧,生计分化能够弱化草原生态补奖政策对牲畜养殖规模扩大的促进作用;在“倒U型”曲线的右侧,生计分化能够促使补奖金额对牲畜养殖规模的负向影响趋于放缓,有助于避免因补奖金额的增加引致牲畜养殖数量的锐减。根据以上结论,建议政府应进一步提高补奖标准以增强补奖弥补损失的有效性,重视发挥农牧民生计分化在牲畜养殖规模调控中的作用。     

Coupling loss characteristics of N-P-C through runoff and sediment in the hilly region of SE China under simulated rainfall

Environmental Science and Pollution Research - Soil total carbon (TC), phosphorus (P), and nitrogen (N) exports from the weathered granite slopes are greatly influenced by the complex hydrological...     

腐殖酸对As(V)在覆铁砂介质中吸附行为的影响

对腐殖酸(HA)进行了成分分析及红外表征,并从HA浓度、pH值、As(Ⅴ)初始浓度等方面,研究了HA对As(Ⅴ)在覆铁砂介质中吸附行为的影响.结果表明,随着HA浓度的升高,总砷去除率逐渐降低.当HA浓度增加到25mg.l-1时,与不存在HA条件下相比,总砷去除率降低了12%左右.溶液pH值影响As(Ⅴ)的去除,pH值从6升高到8时,总砷去除率从52.1%降到了39%.其中的作用机理主要是HA与As(Ⅴ)在覆铁砂表面形成竞争吸附,HA争夺了As(Ⅴ)的吸附点位.此外,HA与Fe(Ⅲ)的络合作用也是导致覆铁砂对砷的去除率降低的一个重要原因.     

淮河流域安徽段水系沉积物中多环芳烃的污染性状研究

应用气相色谱质谱联用仪测定淮河流域安徽段水系沉积物样品中萘、二氢苊、苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、、苯并[a]芘和二苯并[a,h]蒽等12种多环芳烃的质量分数,并在此基础上分析沉积物中多环芳烃的区域分布、污染特征和来源。结果表明：研究区水系沉积物中多环芳烃有一定程度的富集,但与国内其他河流相比,样品中多环芳烃的质量分数不高;淮河南北岸支流沉积物中多环芳烃的含量差异比较明显,尤其是东淝河,含量明显低于淮北平原上的其它河流;淮河主干道和北岸支流沉积物中4环以上的多环芳烃含量较高,而南岸支流的淠河和东淝河沉积物中2～3环的多环芳烃平均含量明显高于其他环数;通过污染来源分析,沉积物中多环芳烃除与天然成岩过程有关外,大都是由有机物质的燃烧与热解引起的。     

浅谈高职院校中长跑教学方法

高职院校大学生体质健康水平总体是呈下降的趋势,尤其表现在耐力素质的下降.提高耐力素质的简单有效地途径就是中长跑,但中长跑动作单一,体力消耗大,枯燥乏味,是最不受大学生亲睐的体育项目.为此,我院在体育教学当中,把提高大学生对中长跑锻炼的认识及适应的能力,改进教学方法等措施放在工作的重点.参3.     

戊吡虫胍对几种非靶标生物的急性毒性

戊吡虫胍是一种从烟碱类和缩胺脲类杀虫剂活性结构拼接而成的系列化合物中筛选出来的新型杀虫剂,目前戊吡虫胍对非靶标生物的毒性研究报道较少。为探究戊吡虫胍的环境安全性,采用生物毒性试验方法测定了其对斜生栅藻(Scenedesmus obliquus)、大型溞(Daphnia magna)、家蚕(Bombyx mori)、斑马鱼(Brachydanio rerio)、赤子爱胜蚯蚓(Eisenia fetide)、非洲爪蟾(Xenopus laevis)、赤眼蜂(Trichogramma nubilale)、意大利蜜蜂(Apis mellifera)、日本鹌鹑(Coturnix coturnix japonica)共9种非靶标生物的急性毒性。结果显示戊吡虫胍对斜生栅藻和大型溞的半数有效浓度(EC50)分别为8.79 mg·L~(-1)和10.97 mg·L~(-1),对家蚕、斑马鱼、赤子爱胜蚯蚓和非洲爪蟾的半数致死浓度(LC50)分别为2.32 mg·L~(-1)、13.74 mg·L~(-1)、100 mg·kg~(-1)和19.30mg·L~(-1),对赤眼蜂的安全系数为0.16~0.031,对蜜蜂急性触杀和急性摄入毒性分别为51.82μg·bee~(-1)和10.8×10~3mg·L~(-1),对鹌鹑的急性经口和急性饲喂毒性LC50分别为1 000 mg·kg~(-1)和2×103mg·kg~(-1)。按照最新国标(GB/T31270—2014)化学农药环境安全评价准则的毒性等级划分,戊吡虫胍除了对家蚕和赤眼蜂为高毒和极高风险外,对其余非靶生物均为低毒。     

搅拌方式对絮凝除藻效果的影响

以铜绿微囊藻为研究对象,测试了不同振荡方式(回旋式与往复式),不同振荡强度及不同藻细胞密度对絮凝剂絮凝沉降效果的影响,同时还研究了絮凝沉降发生后,藻细胞再悬浮的主要影响因素.结果表明,回旋式搅拌处理下产生的絮凝效果要明显优于往复式振荡,60r/min回旋式搅拌1min可以得到100%的去除率,而往复式搅拌可得到的最佳去除率仅为30.7%;且絮凝效果随搅拌强度的增加有明显提高;藻细胞密度越高,需要的搅拌强度也越大;絮凝沉降后的静置时间越长,则越不容易发生再悬浮.     

Mechanistic origins of variability in phytoplankton dynamics. Part II: analysis of mesocosm blooms under climate change scenarios

Driving factors of phytoplankton spring blooms have been discussed since long, but rarely analyzed quantitatively. Here, we use a mechanistic size-based ecosystem model to reconstruct observations made during the Kiel mesocosm experiments (2005–2006). The model accurately hindcasts highly variable bloom developments including community shifts in cell size. Under low light, phytoplankton dynamics was mostly controlled by selective mesozooplankton grazing. Selective grazing also explains initial dominance of large diatoms under high light conditions. All blooms were mainly terminated by aggregation and sedimentation. Allometries in nutrient uptake capabilities led to a delayed, post-bloom dominance of small species. In general, biomass and trait dynamics revealed many mutual dependencies, while growth factors decoupled from the respective selective forces. A size shift induced by one factor often changed the growth dependency on other factors. Within climate change scenarios, these indirect effects produced large sensitivities of ecosystem fluxes to the size distribution of winter phytoplankton. These sensitivities exceeded those found for changes in vertical mixing, whereas temperature changes only had minimal impacts.