Response of cucumber plants to increased UV-B radiation under water stress

ＩｎｔｒｏｄｕｃｔｉｏｎＤｕｒｉｎｇｔｈｅｐａｓｔｓｅｖｅｒａｌｄｅｃａｄｅｓｎｕｍｅｒｏｕｓｉｎｖｅｓｔｉｇａｔｉｏｎｓｏｎｐｒｏｄｕｃｔｉｖｉｔｙ,ｐｈｙｓｉｏｌｏｇｙａｎｄｅｃｏｌｏｇｙｏｆｐｌａｎｔｓｓｕｂｊｅｃｔｅｄｔｏｔｈｅｉｎｃｒｅａｓ?..     

大亚湾海洋生物体中的砷

为也了解大亚湾海洋生物体Ａｓ含量的背景水平，１９９３年大亚湾１５个测站采集了海洋样品，对其Ａｓ含量进行了测定和评价。鱼类，甲索类，头足类和贝类Ａｓ含量的平均值分别为０．４５×１０＾－６，４．７０×１０＾－６，２．２８×１０＾－６和５．５７×１０＾－６，表现出明显的种类间差异。     

辽东湾海冰中微生物的分离

本文报道了辽东湾４个采样点海冰样品中异差细菌异养真菌、粪大菌群等微生物的分离，并用海水和淡水培养基分别对其进行了菌数分离比较，同时还对其中两个采样的冰下水与沉积物样品做了分离对照。结果表明，海冰（化冰水）样品中异养细菌的丰度为：１０＾３－１０＾５ＣＦＵ／ｄｍ＾３，异养真菌为：１０＾１－１０＾２ＣＦＵ／ｄｍ＾３；弧菌为；〈１０＾２－１０＾３ＣＦＵ／ｄｍ＾３；石油烃降解菌为：１０＾２－１０＾４ＣＦＵ／     

Influence of Llamas, Horses, and Hikers on Soil Erosion from Established Recreation Trails in Western Montana, USA

/ Various types of recreational traffic impact hiking trails uniquely and cause different levels of trail degradation; however, trail head restrictions are applied similarly across all types of packstock. The purpose of this study was to assess the relative physical impact of hikers, llamas, and horses on recreational trails. Horse, llama, and hiker traffic were applied to 56 separate plots on an existing trail at Lubrecht Experimental Forest in western Montana. The traffic was applied to plots at intensities of 250 and 1000 passes along with a no-traffic control under both prewetted and dry trail conditions. Soil erosion potential was assessed by sediment yield and runoff (using a Meeuwig type rainfall simulator), changes in soil bulk density, and changes in soil surface roughness. Soil moisture, slope, and rainfall intensity were recorded as independent variables in order to evaluate the extent that they were held constant by the experimental design. Horse traffic consistently made more sediment available for erosion from trails than llama, hiker, or no traffic when analyzed across wet and dry trail plots and high and low intensity traffic plots. Although total runoff was not significantly affected by trail user, wet trail traffic caused significantly greater runoff than dry trail traffic. Llama traffic caused a significant increase in sediment yield compared to the control, but caused erosion yields not significantly different than hiker traffic. Trail traffic did not increase soil compaction on wet trails. Traffic applied to dry trail plots generally resulted in a significant decrease in soil bulk density compared to the control. Decreased soil bulk density was negatively correlated with increased sediment yield and appeared to result in increased trail roughness for horse traffic compared to hiker or llama traffic. Differences described here between llama and horse traffic indicate that trail managers may want to consider managing packstock llamas independent of horses.KEY WORDS: Recreational impacts; Sediment yield; Trail degradation     

Sources and Distribution of Polychlorinated Terphenyls at a Major US Aeronautics Research Facility

O -deethylase (EROD) activity to a similar degree as PCB Aroclor 1254 and to a greater extent than PCT Aroclor 5460. The presence of high concentrations of PCTs contributed to the facility being included on the National Priorities List. It subsequently became the first US federal facility to sign a Federal Facility Agreement, identifying cleanup responsibilities, prior to formal listing.     

Effects of Grazing Pressure on Succession Process and Productivity of Old Fields on Mediterranean Islands

Poterium spinosum, competitive under conditions of overgrazing and fire, accounted for 70%–85% of the total plant cover in all sites, except Santorini, where participation of spiny species was very low. In the recently abandoned sites, annuals accounted for 50%–60% of the standing biomass, but constituted only a tiny fraction in those abandoned for 30 years or more. This was not paralleled by any remarkable increase of the total plant cover. In fact, the yearly produced green biomass decreased with the years after abandonment. The productivity of old fields abandoned for a long time is insufficient to support the grazing animals present. This shortfall, given the animals' requirements, is most dramatic in Symi. The nonrecovering vegetation in the old fields of these mountainous islands constitutes a severe environmental threat; remedial measures appear imperative.     

Prediction Intervals for Estimates of Site Index Based on Ecosystem Type

/ British Columbia has an ecosystem classification system that classifies sites into site series. Foresters commonly measure the productivity of these sites by their site index. In British Columbia, site index is defined as the height of a stand at breast height age 50 and is usually estimated from height-age models. Biogeoclimatic site series/site index relationships are an increasingly popular method of estimating site index in British Columbia for stands where site index cannot be reliably estimated with height-age models. The precision of the predicted site index from these relationships can be evaluated with prediction intervals. This is done for the predicted site index of a single site, a group of sites, or the areally weighted site index of a group of sites. The methodology is also useful in determining the number of sites required to meet a specified precision. These prediction intervals will assist foresters in making sound forest management decisions.KEY WORDS: Biogeoclimatic Ecosystem Classification; Precision; Prediction interval; Site index; Site series     

晋江河口水域中COD的自净特征及其成因分析

利用连续１１ａ的水质监测资料和其它有关的监测，调查资料，研究晋江河口水域中ＣＯＤ的短期和长期自净特征。发现盐度梯度是该特征的主要因素。河口水域的这一特征在区域水环境研究方面具有十分重要的意义。     

对我国城市污水海洋处置的思索

本文结合国内外污水海洋处置趋势分析，针对甸沿海社会经济和环境特征，阐述排海工程在保护近海环境方面的作用和意义。并就海洋自净能力，城市污水处理设施和排海工程的效益等问题进行了讨论，提出了完善近岸海域环境功能区划，开展海洋生态效应和污水海洋处置规划研究以及开拓资金渠道建议。     

大亚湾核电站运转前后附近地区动物体肝组织、红细胞中超氧物歧化酶活性

本文采用邻苯三酚自氧化法，测定了大亚湾核电站Ⅰ、Ⅱ号机组运转前与后第１年、第２年附近地区动物体肝组织及红细胞中超氧物歧化酶（ＥＣ１．１５．１．１Ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕｔａｓｅ，ＳＯＤ）活性变化，结果发现Ⅰ、Ⅱ号机组运转后第１年与第２年，鱼类，细鳞（ＴｈｅｒａｐｏｎＪａｒｂｕａ）红细胞与肝组织中ＳＯＤ活性较运转前明显升高（Ｐ＜０．０５），血红蛋白略有下降，肝组织蛋白无明显变化，两栖类动物蟾蜍（Ｂｕｆｏｍｅｌａｎｏｓｔｉｃｔｕｓ）红细胞ＳＯＤ活性运转后亦明显升高（Ｐ＜０．０１），但肝组织中ＳＯＤ活性呈现下降（Ｐ＜０．０５），血红蛋白及肝组织蛋白无明显性变化，本文对其变化可能原因进行了讨论。