Electrosensory basis for individual recognition in a weakly electric, mormyrid fish, Pollimyrus adspersus (Günther, 1866)

Pollimyrus adspersus discriminates the individually variable waveforms of Electric Organ Discharges (EODs) of conspecifics of only 150–250 s duration. We examined: (1) the discrimination threshold for artificially generated EODs of similar waveform, (2) the mechanism of signal analysis (spectral vs temporal) present, by determining the discrimination between different waveforms of identical amplitude spectra, and (3) the threshold field intensity and reach of discrimination. The triphasic P. adspersus EOD waveform was artificially generated by superimposing two Gaussians, one wide, the second narrow, inverted, and of threefold amplitude. The natural variability among individual EOD waveforms was simulated by phase-shifting one Gaussian relative to the other. The symmetrical waveform where the peaks of the two Gaussians coincided was used as a reference (phase shift=0, rewarded stimulus S+). Results were: (1) in food-rewarded conditioning experiments, trained fish (N=7) detected a phase-shift in artificial EOD stimuli as low as 2 s (N=2 fish), 6 s (N=1) and 10 s (N=1). (2) All fish tested (N=3) discriminated between artificial EODs of identical amplitude spectra but different waveforms (hence, different phase spectra), demonstrating a temporal mechanism of signal analysis. (3) The maximum reach of waveform discrimination was 130 cm at 4.9 V_p-p/cm and 100 S/cm water conductivity (test signal generated at natural amplitude), that is, similar to the reach of EOD detection. Therefore, among the three kinds of electroreceptor organ present in mormyrids, we consider Knollenorgane the relevant sensory organs for EOD waveform discrimination.Communicated by J. Krause     

Temporal Trends of Non-sea Salt Sulfate and Nitrate in Wet Deposition in Japan

Temporal trends of non-sea salt (nss-) sulfate and nitrate were analyzed from nationwide precipitation chemistry measurements provided by the Ministry of the Environment (MOE) for the 1988–2002 fiscal years (April–March). The concentrations and deposition of nss-sulfate were found to be decreasing, and those of nitrate were stable or slightly increasing at most sites. These deposition trends were discussed from the viewpoint of emissions of SO₂ and NO_X during the period of interest. Because monitoring techniques have changed in the number of active sites, samplers, and analytical methods during the operation period, the median of all annual depositions measured in Japan in a specific year was selected as the annual representative. The contribution of specific emission sources was also calculated for 1990 on the basis of the nss-sulfate and nitrate deposition in Japan obtained with a model simulation in which the model did not include volcanic emissions from Mt. Oyama, Miyakejima Island, which began to erupt suddenly and violently in 2000. For nss-sulfate, the calculated deposition agrees well with the intensity and trends of the median up to 1999. After 2000, a higher deposition than calculated in the preceding years was evident, which is attributable to the volcanic SO₂ from Mt. Oyama. For nitrate, both the calculated and observed depositions were slightly increasing; however, the calculation was found to exceed the observation.     

基于不同测序技术的生物群落结构及功能菌分析

分别采用克隆文库和高通量测序技术,解析生物去除铁锰氨滤池内微生物的群落结构和功能菌多样性,并探讨不同测序手段的差异.高通量测序获得15057条有效序列、共32个分类纲,克隆文库测序涵盖9个具有明确分类地位的纲(75条序列),前者能揭示更为丰富的细菌群落结构多样性.功能菌(铁锰氧化细菌和硝化细菌)分析过程中,一些功能菌属在克隆文库中出现,而在高通量测序中未检测到,反之亦然.与单一的测序手段相比,二者相结合能更好地揭示功能细菌的分布特点.     

Simulating the temporal pattern of waste production in farmed gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and Atlantic bluefin tuna (Thunnus thynnus)

Most fish farming waste output models provide gross waste rates as a function of stocked or produced biomass for a year or total culture cycle, but without contemplating the temporality of the discharges. This work aims to ascertain the temporal pattern of waste loads by coupling available growth and waste production models and developing simulation under real production rearing conditions, considering the overlapping of batches and management of stocks for three widely cultured species in the Mediterranean Sea: gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and Atlantic bluefin tuna (Thunnus thynnus). For a similar annual biomass production, the simulations showed that waste output and temporal dumping patterns differ between the three species as a result of the disparities in growth velocity, nutrient digestibility, maintenance metabolic budget and husbandry. The simulations allowed the temporal patterns including the periods of maximum discharge and the dissolved and particulate nitrogen and phosphorus content in the wastes released to be determined, both of which were seen to be species-specific.     

Ensuring the environmental effectiveness of linked emissions trading schemes over time

Linking emissions trading schemes allows the combined emissions cap to be achieved at lower cost. Linking is usually environmentally neutral, but some design features can lead to higher aggregate emissions if schemes are linked. Technical solutions to limit the potential emissions increases due to design differences implemented when schemes are linked are not sufficient to ensure the environmental effectiveness of the linked schemes over time. Technological, economic, administrative and other changes that can lead to higher aggregate emissions are inevitable. The administrators of the linked schemes must ensure the stringency of the emissions cap relative to the “business as usual” emissions of affected sources, the accuracy of the emissions reported by affected sources, the integrity of the allowance registry, effective compliance enforcement, and the environmental integrity of the credits issued for emission reduction projects over time. This will require a process for agreeing on revisions to the regulations of the linked schemes, a mechanism to provide assurance of the environmental effectiveness of each of the linked schemes, and a procedure for terminating the linking agreement.

大气汞的时空分布研究进展

大气汞是汞全球循环的组成部分，探索汞在大气中的时空分布对于研究其地球化学循环具有重要意义。本文综述了大气汞时空分布的研究现状，主要包括大气汞的来源，形态分布，空间分布度时间分布。研究表明，大气汞具有扩散范围广，空间变异大，时间变化规律性强的特点，同时还指出扩大时空分布研究范围和建立污染和预测模型是未来的研究重点。     

综合水质标识指数法在浑河水质评价中的应用

综合评价水环境质量,全面把握流域水环境污染特征是水环境污染防治中的重要基础性工作。水质标识指数可以完整标识水质评价指标的类别、水质数据、功能区目标值等重要信息,在单因子水质标识指数法基础上建立的综合水质标识指数法能完整表达河流总体的综合水质信息,既不会因个别水质指标较差就否定综合水质,又能对综合水质做出合理的评价;既可以在Ⅰ到Ⅴ类中比较水质的优劣,亦可以对劣Ⅴ类进行评价。为系统全面地研究浑河流域各不同河段水环境特征,将浑河流域划分为3个控制单元,根据2001—2010年间水质监测数据,采用综合水质标识指数法,识别出各控制单元主要污染因子,并阐明了浑河流域水环境质量时空变化规律,本研究即体现了全流域统筹考虑的系统思想,又体现了分区研究的针对性特点,并首次将综合水质标识指数法应用于浑河流域水质综合评价,其研究结论对水质监测数据的评价有一定的借鉴作用,亦对流域水污染防治对策的提出有一定的指导意义。