Riverbank Stabilization of Lead Contaminated Soils Using Native Plant Vegetative Caps

Hamburg is a small borough located in Berks County, Pennsylvania. During the 1940s and 1950s, crushed automobile battery casings, containing high levels of lead, were used as fill in and around Hamburg. Several of the fill areas were along the eastern bank of the Schuylkill River and the Schuylkill River Canal. To reduce exposure to human and ecological receptors, the United States Environmental Protection Agency (U.S. EPA) initiated actions at several of the fill areas. Remediation actions at three of these fill areas, the Berry Property, the Hamburg Playground City Playground, and the Port Clinton Avenue site, utilized native plants, slope stabilization, and soil caps.

The Berry Property consisted of a flat, wooded area adjacent to the river. The Hamburg Playground consisted of a steep wooded slope between the river and the parking lot for the municipal park. The Port Clinton Avenue site consisted of flat and sloped, wooded, and old-field areas between the canal and Port Clinton Avenue. At each of the three sites, some of the contaminated soils were excavated and the remainder was graded and capped. The clean soil cap was then covered with an erosion control mat, seeded with native grasses, and planted with native shrubs. At the Hamburg Playground and Port Clinton Avenue site, the existing trees and much of the existing vegetation were maintained to preserve the slope stability and the natural environment. Great care was taken to ensure community access to the municipal park. Some of the important considerations included retaining the existing trees, dealing with invasive species, maintaining the plants during a drought, and channeling storm-water runoff. The work was coordinated with the Hamburg Borough Council, the Schuylkill River Greenway Association, and the Pennsylvania Department of Environmental Protection (PADEP).

The actions resulted in a stabillized slope with channelized storm water to control erosion and protect the river, a clean soil and plant cover that eliminates exposure to human and animal receptors, and an aesthetically pleasing and usable area that meets the needs of the community and the local conservation/environmental organization.     

Cross-Scale Patterns in Shrub Thicket Dynamics in the Virginia Barrier Complex

Abstract To interpret broad-scale erosion and accretion patterns and the expansion and contraction of shrub thickets in response to sea level rise for a coastal barrier system, we examined the fine-scale processes of shrub recruitment and mortality within the context of the influence of ocean current and sediment transport processes on variations in island size and location. We focused on Myrica cerifera shrub thickets, the dominant woody community on most barrier islands along the coastline of the southeastern USA. Observations suggest that M. cerifera, a salt-intolerant species, is increasing in cover throughout the Virginia barrier islands, yet rising sea level in response to climate change is increasing erosion and reducing island area. Our objective was to explain this apparent paradox using pattern–process relationships across a range of scales with a focus on ocean currents and sediment transport interacting with island characteristics at intermediate scales. Multi-decadal comparisons across scales showed a complex pattern. At the scale of the entire Virginia barrier complex, modest decreases in upland area were accompanied by large increases in shrub area. Responses were more variable for individual islands, reflecting inter-island variations in erosion and accretion due to differences in sediment transport via ocean currents. Several islands underwent dramatic shrub expansion. Only for within-island responses were there similarities in the pattern of change, with a lag-phase after initial shrub colonization followed by development of linear, closed canopy thickets. Understanding the fine-scale processes of shrub seedling establishment and thicket development, in conjunction with the influence of ocean currents and sediment transport, provides a framework for interpreting island accretion and erosion patterns and subsequent effects on shrub thicket expansion or contraction across scales of time and space.     

A palynological reconstruction of pre-European riparian vegetation at Wollombi, New South Wales and its application to stream bank management and revegetation

Summary A palynological investigation was conducted on sediments from three small floodplain swamps on upper Wollombi Brook in the Hunter Valley NSW in order to reconstruct pre-European riparian vegetation composition and community structure. Pre-European riparian plant communities on upper Wollombi Brook were characterized by wet sclerophyll forest associations with rainforest elements (most likely close to the channel). Major changes in both the nature and extent of riparian vegetation have been associated with European settlement. The pre-European pollen spectra assists the identification of a suite of native taxa potentially suitable for use in riparian revegetation operations, particularly in highly cleared streambank sites where protection of water quality and aquatic habitat is an important goal but where insufficient local remnants are available to indicate pre-existing plant species. The research emphasizes the use of palaeoenvironmental evidence as a tool for contemporary environmental management.     

腾格里沙漠东南缘人工植被区降水入渗与再分配规律研究

试验于2001年8月17日至9月30日在中国科学院沙坡头沙漠试验研究站进行,主要利用时域反射仪(TDR)连续测量土壤剖面水分含量的方法,观测受植物根系吸水,蒸散作用影响下的人工植被荒漠灌木柠条(Caragana korshinskii)群落区固定沙丘降水入渗与再分配过程。土壤体积含水率由水平埋设在植物根系剖面内12个深度层次(5～200cm)的时域反射仪探头每小时自动测定1次。天然降水条件下的土壤入渗速率由入渗深度与相应的入渗时间之比值计算得到。结果表明：在7次不连续降水过程中,土壤入渗速率与降水强度呈简单线性相关关系,土壤入渗速率约为降水强度的10倍强。然而当次降水过程中降水强度小于0．46mm／h时,土壤入渗速率约为0cm／h,此时的降水对人工植被固定沙丘区的土壤基本上没有水分补给作用。受荒漠灌木柠条根系吸水作用的影响,其根系密集剖面深度40～140cm内降水水分入渗积累不明显。降水入渗速率及入渗深度受土壤剖面初始含水率多寡而变化,干燥土壤剖面有助于提高入渗速率及入渗深度。降水以后随着时间的推移,区域环境内空气温度、湿度等气象条件适宜,柠条生长进入相对旺盛阶段,其根系密集层140cm深度处土壤含水率在总体上下降的过程中,表现出昼消夜长的趋势,翌日8：00土壤含水率值略高于前一日20：00水分值0．1％～0．3vol．％。     

人工樟子松—差不嗄蒿植被及其固沙作用

植物固沙是整治沙漠和沙漠化土地的一种有效措施。人工植被的建立是植物固沙的必然结果。人工植被的演替、稳定性及其对环境的影响直接关系到流沙的固定程度。因此,本文旨在探讨人工樟子松(Pinus sylvestris var.     

Spatial and temporal variation of community composition and species cover following dune restoration in the Devesa de Albufera (Valencia,Spain).

Plant populations were reintroduced to the coastal dune bar of the Devesa de Albufera from 1988 to 2004; different coastline sections received different species composition and cover. With the aim to detect spatial and temporal variation of floristic diversity, we compared current species composition and cover across the length of the Devesa and across the dune bar with those imposed at the time of restoration. Non-metric multidimensional scaling (NMDS) detected significant differences both across the dune faces and across the coast sections. Differences across the dune faces reflect the sea-inland ecological gradient and resulted from a spatial rearrangement of plant populations: Calystegia soldanella, Achillea maritima and Polygonum maritimum prefer the windward face; Malcolmia littorea and Lagurus ovatus the leeward. Differences across coast sections are related to those at restoration time, with a slow trend towards the homogenization of plant communities. At the current level of anthropic pressure, the plant cover is likely to evolve following the trends pointed out in this research.     

盐胁迫对海岛棉不同基因型幼苗生长及生理生态特征的影响

采用水培试验,分析了不同浓度的NaCl(0、50、100、150、200、250 mmol.L-1)处理对两个海岛棉品种新海28号(XH28,耐盐基因型)和新海21号(XH21,盐敏感基因型)植株生长、生物量分配、蛋白质含量、脯氨酸(Pro)含量以及过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)等生理生态指标的影响。研究发现:(1)盐胁迫对海岛棉幼苗鲜重的影响大于干重,对茎叶的影响大于根系;(2)盐处理引起海岛棉幼苗根叶脯氨酸含量的增加;(3)低浓度NaCl处理(≤50 mmol.L-1)显著增加耐盐品种XH28的根长、株高及单株鲜干重;(4)盐胁迫引起海岛棉幼苗根系中可溶性蛋白质含量下降,相反叶片中可溶性蛋白质含量上升;(5)盐胁迫下耐盐品种XH28幼苗中的POD、CAT、APX酶活性明显高于盐敏感品种XH21,但GR活性显著低于XH21。研究表明,低浓度NaCl处理刺激了棉株生长,增加了生物量;盐胁迫下叶内蛋白质、脯氨酸含量明显增加,POD、CAT、APX酶活力升高是海岛棉耐盐品种XH28的基本特征。     

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.     

Subsurface hydrology and nutrient export from barrier island marshes at different tidal ranges

The vertical flux of water, ammonium, and phosphatewas measured from two developing barrier islandmarshes; Hog Island, VA (1.3 m tidal range) andPritchards Island, SC (2.5 m tidal range). Verticalflow and nutrient concentrations from the deposit weremeasured using seepage meters placed on the surface ofthe marsh. Measured water flow was not significantlydifferent between the sites (average = 60.1 and 57.4l m^-2h^-1for the VA and SC marsh). Verticalflow, calculated from piezometric head gradients andhydraulic conductivity, only accounted for 15 and 4%of measured flow at the VA and SC marshes,respectively. Horizontal flow, calculated as thedifference between measured total flow and calculatedvertical flow, was larger at the SC marsh. Therefore,tidal range seems to influence the direction(horizontal vs. vertical), but not the magnitude oftotal water flow from these developing marshes.Despite a lower tidal range, phosphate flux wassignificantly higher at the VA marsh (69 mmol m^-2yr^-1) relative to the SC marsh (11 mmol m^-2yr^-1) probably because of higher porewaterphosphate concentrations. Measured ammonium flux wasnot significantly different between the sites (194 and174 mmol m^-2yr^-1for the VA and SC marsh).Nutrient concentration must be considered togetherwith tidal range when assessing nutrient export. Thisstudy represents one of few that quantify nutrient andwater export from naturally-developing marshes.Although young marshes are thought to export smallquantities of nutrients and other materials, rates ofnutrient export from these developing marshes weresimilar to rates measured in older marshes. Therelatively high export rates from these developingmarshes were attributed to high rates of subsurfaceflow and high nutrient input from a buried marsh ormudflat located one meter below the present marshsurface. These results have implications fordevelopment of created or restored marshes especiallywhere the goals of those activities are to maximizewetland functions such as nutrient exchange.     

长春花(Catharanthus roseus)对热带珊瑚岛生理生态适应性研究

长春花(Catharanthus roseus)是夹竹桃科的一种亚灌木植物,具有重要的药用价值和观赏价值,在前期的试验性种植中,发现长春花对热带珊瑚岛环境有很强的适应性。为了探讨长春花对热带珊瑚岛环境的生理生态适应性,该文以移植到热带珊瑚岛的长春花和生长于海南省文昌市苗圃的长春花为研究对象,对其叶片的形态解剖结构、生理学特征、营养元素含量等进行了分析。结果表明:(1)与苗圃生长的长春花和其他耐胁迫的植物相比,移植到热带珊瑚岛上的长春花具有叶片厚、栅栏组织发达、比叶面积小等形态解剖特征,这些特征有利于其光能吸收、水分储存和对环境资源的利用。(2)长春花的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性较高,表现出较强的抗氧化性和抗胁迫能力。(3)长春花的叶绿素a和叶绿素b含量较低,可以减少过多的光能进入叶绿体光合系统,防止过剩的光能对光合系统产生伤害。(4)热带珊瑚岛土壤养分含量低,但生长在岛上的长春花叶片的营养元素含量高,表现出很强的养分吸收和利用能力。因此,长春花对干旱、贫瘠等恶劣生境具有很好的适应能力,可以作为热带珊瑚岛植被恢复工具种。     

海岛棉GbTCP14基因的克隆与表达分析

以海岛棉‘新海21号’为试验材料,根据陆地棉GhTCP14基因序列,设计1对引物,通过RT-PCR技术获得海岛棉GbTCP14核苷酸序列,开放阅读框长1 221bp,编码406个氨基酸,分子式C1892H2950N572O620S16,预测分子量为44.134 6kD,等电点为6.88,氨基酸序列包含1个高度保守的TCP结构域及4个低丰度复杂区。GbTCP14蛋白氨基酸序列与其他物种TCP14氨基酸序列比对表明,海岛棉GbTCP14蛋白与其他植物中的TCP14蛋白共同具有一个高度保守的TCP结构域,序列之间的一致性较高。进化树分析表明,海岛棉GbTCP14基因与木本棉GaTCP14基因分布在同一分支上。实时荧光定量PCR表明,海岛棉GbTCP14基因在开花后第15天时表达量最高,在第5~20天时相对表达量比其他时期较高,第25天时相对表达量最低。在不同组织中花瓣和花萼中表达量较高,根和茎中表达量一般,叶组织中表达量最低。通过酵母系统转录激活分析显示,GbTCP14蛋白不具有转录活性。     

Profiling Landforms: Using a Laser Level

Profiling landforms actively involves students in measuring the topography of landforms such as beaches, hillsides, and stream embankments. In this activity, the author describes how to set up an inquiry situation in which students can ask questions, seek answers, and develop explanations about seasonal or weather-related changes in the landscape.