Interpretation reduces ecological impacts of visitors to world heritage site

Minimal-impact interpretation is widely used to reduce the ecological impacts of visitors to protected areas. We tested whether verbal appeals and/or role-model demonstrations of minimal-impact behavior by a trained guide reduced noise, litter, and trampling impacts on hiking trails in a subtropical rainforest. Interpretation did reduce impacts significantly. Different interpretive techniques were more effective for different impacts. The experimental groups were mature, well-educated professionals; interpretation may differ in effectiveness for different visitors. Interpretation by skilled guides can indeed reduce visitor impacts in protected areas, especially if role modeling is combined with verbal appeals.     

Calibration of the Chemcatcher passive sampler for monitoring selected polar and semi-polar pesticides in surface water

Passive sampling is a powerful method for continuous pollution monitoring, but calibration experiments are still needed to generate sampling rates in order to estimate water concentrations for polar compounds. We calibrated the Chemcatcher device with an uncovered SDB-XC Empore disk as receiving phase for 12 polar and semi-polar pesticides in aquatic environments in flow-through tank experiments at two water flow velocities (0.135 m/s and 0.4 m/s). In the 14-day period of exposure the uptake of test substances in the sampler remained linear, and all derived sampling rates R(s) were in the range of 0.1 to 0.5 L/day. By additionally monitoring the release of two preloaded polar pesticides from the SDB-XC disks over time, very high variation in release kinetics was found, which calls into question the applicability of performance reference compounds. Our study expands the applicability of the Chemcatcher for monitoring trace concentrations of pesticides with frequent occurrence in water.     

Light-induced degradation of perfluorocarboxylic acids in the presence of titanium dioxide

The UV-photon-induced degradation of heptafluorobutanoic acid was investigated in acidic aqueous solutions in the presence of titanium dioxide. Heptafluorobutanoic acid could be degraded with this photocatalyst in a light-induced reaction generating carbon dioxide and fluoride anions. Carbon dioxide evolution in a significant amount occurred only in the presence of molecular oxygen and the photocatalyst. The light-induced degradation of trifluoroacetic acid, pentafluoropropanoic acid, nonafluorobutanoic acid, pentadecafluorooctanoic acid, nonafluorobutanesulfonic acid, and heptadecafluorooctanesulfonic acid in the presence of titanium dioxide was also studied. The perfluorocarboxylic acids under investigation are degraded to generate CO(2) and fluoride anions while both perfluorinated sulfonic acids are persistent under the experimental conditions employed in this study. For all compounds photonic efficiencies of the mineralization reaction were estimated to be smaller than 1x10(-5). To increase the photocatalytic activity mixed systems containing homogeneous phosphotungstic acid and heterogeneous titanium dioxide catalysts were also investigated. In the mixtures of these two photocatalysts, the formation rate of CO(2) increased with illumination time.     

气候变暖期间波罗的海海冰的模拟分布及对环斑海豹冬季栖息地的影响

本文调查研究了在目前和未来气候条件下的波罗的海海冰.采用了罗斯比区域大气-海洋模型进行了一系列为时30年的时间片试验.对于两个驱动全球模型HadAM3H和ECHAM4/OPYC3中每一个,都根据SRESA2和B2辐射情景进行一次对照操作(1961～1990年)和两次情景操作(2071～2100年).波罗的海中未来海冰量将平均减少83%.波的尼亚海,芬兰湾和里加湾的大片海域以及芬兰西南群岛的外部将基本上变成无冰区.本文提出的情景是用来研究气候变化对波罗的海环斑海豹(Phoca hispida botnica)的影响.气候变化看来是对所有南方种群的主要威胁.惟一还算不错的冬季海冰生境只限于波的尼亚湾.     

波罗的海高盐传送带,或波罗的海中的翻转环流及咸、淡水的混合

我们使用三维波罗的海模型模拟的做法进行了一项波罗的海水团环流的研究.来自北大西洋的咸水经丹麦海峡流入波罗的海,在波罗的海上涌并与从各河流流入的淡水混合形成"波罗的海高盐传送带".我们利用翻转流量函数和拉格朗日轨迹线对来自大贝尔特和厄勒海峡的成水与淡水的混合情况进行了调查.该翻转流量函数被作为一种具有4个不同垂直坐标(深度、盐度、温度和密度)的函数进行计算,以便了解水的路径以及它在什么地方上涌并混合.在波罗的海本体内发现了与南大洋中的迪肯环流(Deacon Cell)类似的虚拟深度翻转环流的存在,它与哥特兰岛附近的旋转环流相符,当翻转流量函数投射在密度层上时,这一虚拟深度翻转环流就消失了.我们已经开展了一项拉格朗日轨迹线研究,以便更好地认识该环流以及咸水与淡水的混合情况.对这些水团在波罗的海中的停留时间的计算结果为26～29年,而拉格朗日扩散在5年后达到海盆饱和.     

The phylogeny of archaebacteria,including novel anaerobic thermoacidophiles in the light of RNA polymerase structure

DNA-dependent RNA polymerases of archaebacteria are distinct from those of eubacteria both in structure and in function. They show similarities to those of the eukaryotic cytoplasm. Extremely thermophilic anaerobic sulfur-respiring archaebacteria isolated from solfataric waters represent four different families, the Thermoproteaceae, the “stiff filaments”, the Desulfurococcaceae and the Thermococcaceae, of a novel order, Thermoproteales. Together with the Sulfolobales, they form the second branch of the urkingdom of the archaebacteria besides that of the methanogens and extreme halophiles. Thermoplasma appears isolated.     

Evenly dispersed social groups and intergroup competition for juveniles in a coral-reef fish

Summary A model based on current knowledge of recruitment of settling juveniles of coral-reef fishes suggests that adult social groups far removed from their nearest neighbors can expect to attract larger numbers of juveniles than groups that are close to nearest neighbors. For protogynous fishes in which females change to males when intragroup, female-to-male sex ratios rise above threshold values, selection should favor individuals occupying groups that attract many juveniles. The model predicts that social groups should, in consequence, be regularly dispersed and that, in effect, groups compete with each other to attract juveniles. Dispersion of social groups was measured in two populations of the protogynous fish Anthias squamipinnis. The location of all groups were plotted on maps of the reef. A set of nearest-neighbor analyses applied to the data all showed significant departures of observed nearest-neighbor distances from randomness, in the direction of regularity. At both sites, neighboring groups were separated by much unoccupied space. In one population, the substrate consisted of discrete coral aggregates scattered over open sand bottom, while in the second population groups occupied a relatively continuous vertical reef face. Although regular dispersion could, in theory, result from regular distribution of food patches, current evidence does not favor this explanation. It is more likely that regular dispersion results either from the reproductive advantage of occupying groups that are highly attractive to juveniles, as seen in the model, or from limited perceptual and locomotor abilities of juveniles at the time of settlement.     

The Baltic haline conveyor belt or the overturning circulation and mixing in the Baltic

A study of the water-mass circulation of the Baltic has been undertaken by making use of a three dimensional Baltic Sea model simulation. The saline water from the North Atlantic is traced through the Danish Sounds into the Baltic where it upwells and mixes with the fresh water inflow from the rivers forming a Baltic haline conveyor belt. The mixing of the saline water from the Great Belt and Oresund with the fresh water is investigated making use of overturning stream functions and Lagrangian trajectories. The overturning stream function was calculated as a function of four different vertical coordinates (depth, salinity, temperature and density) in order to understand the path of the water and where it upwells and mixes. Evidence of a fictive depth overturning cell similar to the Deacon Cell in the Southern Ocean was found in the Baltic proper corresponding to the gyre circulation around Gotland, which vanishes when the overturning stream function is projected on density layers. A Lagrangian trajectory study was performed to obtain a better view of the circulation and mixing of the saline and fresh waters. The residence time of the water masses in the Baltic is calculated to be 26-29 years and the Lagrangian dispersion reaches basin saturation after 5 years.