Hydrodynamic Modeling Improves Green River Reconnection with Floodplain Wetlands for Endangered Fish Species Recovery

We performed two‐dimensional (2D) hydrodynamic modeling to aid recovery of the endangered razorback sucker (Xyrauchen texanus) by reconnecting the Green River with its historic bottomland floodplain wetlands at Ouray National Wildlife Refuge, Utah. Reconnection allows spring flood flows to overtop the river levee every two to three years, and passively transport razorback sucker larvae to the wetlands to grow in critical habitat. This study includes (1) river hydrologic analysis, (2) simulation of a levee breach/weir, overtopping of river flood flows, and 2D flow through the wetlands using Hydrologic Engineering Center River Analysis System 2D, and (3) modeling flow and restoration scenarios. Indicators of hydrologic alteration were used to evaluate river flow metrics, in particular flood magnitudes, frequency, and duration. Results showed a target spring flow of 16,000 cfs (453 m³/s) and a levee breach elevation of 4,663 ft (1,421 m) amsl would result in a median flow >6,000 acre‐feet (7.4 million m³) over five days into the wetlands, which is adequate for razorback sucker larvae transport and rearing. Modeling of flow/restoration scenarios showed using gated water control structures and passive low‐water crossings between wetland units can provide adequate control of flow movement into and storage in multiple units. Levee breaching can be a relatively simple, cost‐effective method to reconnect rivers and historic floodplains, and hydrodynamic modeling is an important tool for analyzing and designing wetland reconnection.     

不同替代修复年限对飞机草种群和本土植物群落结构的影响

为研究替代修复对飞机草的治理效果以及对本地植物群落结构的修复效应,选择修复3、5、10 a和未修复（CK）的飞机草入侵生境为研究对象,调查飞机草密度、盖度、生物量、基径和本土植物群落的物种多样性、盖度等指标,采用“空间代替时间”的方法,分析不同修复年限飞机草种群特征和本地植物群落结构的变化.结果表明:①随着修复年限的增加,飞机草密度、盖度、基径、生物量等指标均呈显著降低趋势;修复10 a后,飞机草的盖度、密度、生物量、基径相比对照分别降低了97.3%、96.5%、98.6%、85.7%,飞机草入侵得到明显控制.②在植被替代修复过程中,飞机草入侵生境的群落结构得到明显改善,草本层物种多样性呈先升后降再升的趋势,草本层盖度在修复3 a后显著升高随后又显著降低,灌木层和乔木层物种多样性和盖度均呈显著增加趋势.研究显示,替代修复能有效治理飞机草入侵,促进植物群落的正向演替,提高本地植物群落结构的稳定性,增强生态系统对外来物种入侵的抵抗力.      

典型胶合板制造企业VOCs排放特征

通过苏玛罐采样和GC-MS/FID分析系统,测定了山东地区典型胶合板制造企业的VOCs排放特征.结果表明,烷烃（13.81%~39.16%）、含氧VOCs（5.68%~36.06%）和芳香烃（3.58%~48.12%）是热压和涂胶工艺主要排放成分,废气排口以含氧VOCs（6.49%~83.88%）排放为主,不同工艺环节的特征VOCs组分各有不同;烯炔烃（27.12%~39.38%）和芳香烃（32.47%~45.63%）是热压工艺和涂胶工艺的高OFP组分,废气排口则以含氧VOCs（52.82%）对O₃生成贡献最大;基于SOAP评估,各环节均以芳香烃类化合物（97.08%~98.03%）为主要活性组分;测得山东地区胶合板制造行业VOCs排放因子为0.89g VOCs/m³胶合板.     

叶菜类蔬菜产地镉环境质量类别划分技术研究

以农业农村部环境监测总站对我国主要叶菜类蔬菜产地的例行监测数据为基础,综合考虑种类和土壤理化性质的影响,深入探讨了应用物种敏感性分布法（SSD）基于不同累积概率建立我国叶菜类蔬菜产地“优先保护类、安全利用类和严格管控类”的土壤镉环境质量类别划分阈值,并对其合理性验证.结果表明：pH值、阳离子交换量（CEC）和土壤有机质（SOM）对叶菜类蔬菜富集镉的影响均达到了极显著水平（P<0.01）,并由其构建的三因子生物有效性模型为lgBCF=-0.122pH+0.025lgSOM-0.048lgCEC+1.252（R²=0.746,P<0.01,n=134）,可解释叶菜类蔬菜富集系数74.6%的变异;利用上述模型将不同土壤理化性质条件下叶菜类蔬菜镉的生物富集系数（BCF）归一化处理可最大程度降低土壤理化性质对其富集镉的影响,凸出叶菜类蔬菜的内在敏感性;利用归一化后的BCF通过log-logistic拟合函数构建SSD曲线得到,不同叶菜类蔬菜种类对镉的敏感性差异明显;依据SSD曲线基于保护80%、50%和5%的叶菜类蔬菜种类分别推导出pH≤6.5、6.5相似文献   

城市污水二级处理出水中不同种类PPCPs的臭氧氧化效果与机制研究

研究了臭氧氧化对城市污水二级处理出水中15种典型药品和个人护理品（PPCPs）的去除效果及O₃分子氧化和·OH自由基氧化的贡献.结果表明,PPCPs的臭氧氧化去除效果与其亲核官能结构特性相关,芳香胺结构为主的PPCPs易降解,烷基胺结构为主的PPCPs可部分降解,亲核特性较弱的双键为主的PPCPs难降解;在臭氧投加量为5.5 mg·L^-1条件下,这3类PPCPs的去除率为分别为大于95%、57%~68%和39%~57%.臭氧氧化过程中,O₃分子氧化和·OH自由基氧化均起重要作用.易降解PPCPs的氧化机制以O₃分子氧化为主,贡献率为82%~91%;可降解和难降解PPCPs的氧化机制以·OH自由基氧化为主,贡献率分别为48%~71%和66%~94%.二级出水中臭氧氧化过程中,UVA₂₅₄去除率可呈单线性或分段线性指示PPCPs的去除效率.     

微量元素锰对威氏海链藻生长及叶绿素荧光的影响

微藻和高等植物的光系统Ⅱ中的放氧复合体(oxygen-evolving complex,OEC)是裂解水与释放氧气、质子和电子的部位,其中水裂解的反应中心由4个锰原子组成的锰族构成.叶绿素荧光诱导动力学分析技术是研究光合作用特征的有效方法,可以指示不同环境压力下光系统各构件的变化.利用该技术研究了锰添加(0~9 000 nmol·L~(-1)Mn)对威氏海链藻(Conticribra weissflogii)生长及叶绿素荧光特性的影响.结果表明,除最高浓度锰(9 000 nmol·L~(-1)Mn)外,其余浓度锰对威氏海链藻生长的影响均不显著;锰对威氏海链藻叶绿素荧光参数的影响与锰添加的浓度范围有关,且随培养时间的增加而增强:其中,较低浓度锰(90 nmol·L~(-1)Mn)对各叶绿素荧光参数都呈现了强影响效果.尽管锰可能不是威氏海链藻生长的限制因子,但是锰从两方面促进了其光合作用:(1)促进光系统Ⅱ供体侧OEC结构的完整性和从OEC到电子传递中间体Tyr之间的电子传递;(2)促进光系统Ⅱ受体侧的能量转化和QA之后的电子传递.研究还发现,光合作用中与能量转化相关的荧光参数和活性氧(reactive oxygen species,ROS)之间呈显著相关(P 0. 01),表明锰在威氏海链藻光合作用过程及ROS的产生中都扮演着重要角色.     

铈钴复合氧化物催化剂催化CO-SCR反应机理研究

利用共沉淀法制备了一系列Ce-Co-O_x复合氧化物催化剂,并对其CO-SCR反应性能进行了研究.考察了Co和Ce比例对CO-SCR反应活性的影响,确定最佳的Ce和Co复合比例为3：7,最高转化率为84%（250℃）.经表征分析发现,Ce（0.3）-Co（0.7）-O_x上发生CO-SCR的主活性位点是Co.掺杂Ce提升催化性能主要有两方面原因：一是催化剂比表面积增大,提高了表面的吸附位数量;二是Ce-Co-O_x催化剂形成的固溶体提升了氧迁移率.反应机理可能是气态或者弱吸附状态的CO与NO的吸附物种（主要是桥接二齿亚硝酸盐物种和螯合式双齿硝酸盐物种）反应.     

Past and Present Effectiveness of Protected Areas for Conservation of Naturally and Anthropogenically Rare Plant Species

Abstract:  The Global Strategy of Plant Conservation states that at least 60% of threatened plant species should be within protected areas. This goal has been met in some regions with long traditions of plant protection. We used gap analysis to explore how particular groups of species of conservation interest, representing different types of natural or anthropogenic rarity, have been covered by protected areas on a national scale in Estonia during the last 100 years. Species-accumulation curves indicated that plant species that are naturally rare (restricted global or local distribution, always small populations, or very rare habitat requirements) needed almost twice as many protected areas to reach the 60% target as plant species that are rare owing to lack of suitable management (species depending on grassland management, moderate forest disturbances, extensive traditional agriculture, or species potentially threatened by collecting). Temporal analysis of the establishment of protected areas suggested that grouping plant species according to the predominant cause of rarity accurately reflected the history of conservation decision making. Species found in very rare habitats have previously received special conservation attention; species dependent on traditional extensive agriculture have been largely ignored until recently. Legislative initiative and new nature-protection schemes (e.g., Natura 2000, network of protected areas in the European Union) have had a positive influence on all species groups. Consequently, the species groups needing similar action for their conservation are sensitive indicators of the effectiveness of protected-area networks. Different species groups, however, may not be uniformly conserved within protected areas, and all species groups should fulfill the target of 60% coverage within protected areas.