Distribution of White Whales (Delphinapterus leucas) in the White Sea and the Southeastern Region of the Barents Sea during the Ice Season

The habitats, relative occurrence, and distribution of the white whale in the White Sea and the southeastern Barents sea in every month of the ice season have been studied using the results of an aerial ice survey along standard routes from 1970–1991. In these seas, white whales have been found in each month of the ice season, with single animals, groups, schools or gams, herds, and large congregations of several hundred animals accounting for 10, 22.8, 47.2, 12.9, and 7% of all aggregations of white whales observed, respectively. The relative occurrence of white whales in the White Sea is higher in March and May (32.5 and 30%, respectively) and lower in February, January, and November (15, 10, and 7.5%, respectively); in December and April, the whales are observed very seldom (2.5% in both months). In the southeastern Barents Sea, the relative occurrence of white whales is highest in May (53.3%) and considerably lower in December and February (16.7 and 10%); only a few animals are found during the remaining ice season. Regarding different habitats, the relative occurrences of white whales in open water, in water openings in the ice, near the edge of pack ice, and in ice packs with different degrees of closeness are 21.5, 11.4, 45.7, and 21.4%, respectively.     

“白色污染”及废旧塑料的回收利用

阐述了“白色污染”对环境的影响,介绍了废旧塑料的回收再利用技术和处理方法。     

南充市“白色污染”现状及对策措施和建议

本文通过实地调查,分析了南充市“白色污染”现状、危害和治理工作存在的主要问题,提出了治理“白色污染”的对策措施和建议。     

碱法麦草浆漂白废水脱色白腐菌的筛选及脱色研究

从腐木上采集,经多次分离纯化筛选出2株具有较高漂白废水脱色能力的菌株F7、F9,与Phanerochaete Chrysosporium在相同的条件下处理碱法麦草浆CE段混合漂白废水,培养4d脱色率分别为74．44％,46．67％和62．22％。延长培养时间至第8d,F7菌脱色效果不明显,而F9菌脱色可增至67．58％。     

染料脱色菌的筛选及对活性艳红X-3B的脱色研究

从广州某印染厂生化处理池的活性污泥中筛选到三株对活性艳红X-3B具有高效脱色作用的真菌,其中菌株HMX-3的脱色能力最强。考察了培养时间、温度、培养方式、pH值以及染料浓度对HMX-3脱色能力的影响。结果表明,菌株HMX-3对150mg/L X-3B的24h脱色率达65.8%,经60h可使其完全脱色;HMX-3对活性艳红X-3B脱色的最适温度为25℃~35℃,最佳pH值为6~8,且振荡培养较静置培养条件下的脱色率高;随染料浓度的增加,脱色率降低,但对于400mg/L的X-3B在72h时的脱色率可达86.7%。     

Does the preferential microbial colonisation of ferromagnesian minerals affect mineral weathering in soil?

Fungal activity is thought to play a direct and effective role in the breakdown and dissolution of primary minerals and in the synthesis of clay minerals in soil environments, with important consequences for plant growth and ecosystem functioning. We have studied primary mineral weathering in volcanic soils developed on trachydacite in southern Tuscany using a combination of qualitative and quantitative mineralogical and microbiological techniques. Specifically, we characterized the weathering and microbiological colonization of the magnetically separated ferromagnesian minerals (biotite and orthopyroxene) and non-ferromagnesian constituents (K-feldspar and volcanic glass) of the coarse sand fraction (250-1,000 microm). Our results show that in the basal horizons of the soils, the ferromagnesian minerals are much more intensively colonized by microorganisms than K-feldspar and glass, but that the composition of the microbial communities living on the two mineral fractions is similar. Moreover, X-ray diffraction, optical and scanning electron microscope observations show that although the ferromagnesian minerals are preferentially associated with an embryonic form of the clay mineral halloysite, they are still relatively fresh. We interpret our results as indicating that in this instance microbial activity, and particularly fungal activity, has not been an effective agent of mineral weathering, that the association with clay minerals is indirect, and that fungal weathering of primary minerals may not be as important a source of plant nutrients as previously claimed.     

Mushroom harvesting ants in the tropical rain forest

Ants belong to the most important groups of arthropods, inhabiting and commonly dominating most terrestrial habitats, especially tropical rainforests. Their highly collective behavior enables exploitation of various resources and is viewed as a key factor for their evolutionary success. Accordingly, a great variety of life strategies evolved in this group of arthropods, including seed harvesters, gardeners, and planters, fungus growers, nomadic hunters, life stock keepers, and slave makers. This study reports the discovery of a new lifestyle in ants. In a Southeast Asian rainforest habitat, Euprenolepis procera is specialized in harvesting a broad spectrum of naturally growing mushrooms, a nutritionally challenging and spatiotemporally unpredictable food source. While unfavorable to the vast majority of animals, E. procera has developed exceptional adaptations such as a shift to a fully nomadic lifestyle and special food processing capabilities, which allow it to rely entirely on mushrooms. As a consequence, E. procera is the most efficient and predominant consumer of epigeic mushrooms in the studied habitat and this has broad implications for the tropical rainforest ecosystem.     

A spatial model of white sturgeon rearing habitat in the lower Columbia River,USA

Concerns over the potential effects of in-water placement of dredged materials prompted us to develop a GIS-based model that characterizes in a spatially explicit manner white sturgeon Acipenser transmontanus rearing habitat in the lower Columbia River, USA. The spatial model was developed using water depth, riverbed slope and roughness, fish positions collected in 2002, and Mahalanobis distance (D²). We created a habitat suitability map by identifying a Mahalanobis distance under which >50% of white sturgeon locations occurred in 2002 (i.e., high-probability habitat). White sturgeon preferred relatively moderate to high water depths, and low to moderate riverbed slope and roughness values. The eigenvectors indicated that riverbed slope and roughness were slightly more important than water depth, but all three variables were important. We estimated the impacts that fill might have on sturgeon habitat by simulating the addition of fill to the thalweg, in 3-m increments, and recomputing Mahalanobis distances. Channel filling simulations revealed that up to 9 m of fill would have little impact on high-probability habitat, but 12 and 15 m of fill resulted in habitat declines of ∼12% and ∼45%, respectively. This is the first spatially explicit predictive model of white sturgeon rearing habitat in the lower Columbia River, and the first to quantitatively predict the impacts of dredging operations on sturgeon habitat. Future research should consider whether water velocity improves the accuracy and specificity of the model, and to assess its applicability to other areas in the Columbia River.     

自由飞行下基于高斯白噪声的碰撞风险模型

飞机的安全性在自由飞行中受到通信导航监视性能、人为因素、防撞系统等因素的影响,其中通信导航监视性能会导致飞机产生定位误差,这种定位误差具有高斯白噪声的特性。主要考虑飞行定位误差的高斯白噪声特性,将此误差用概率表示为以理论位置向外辐射,根据飞机的相对运动,建立基于高斯白噪声的碰撞风险模型,给出模型中各参数的求解方法,从而得到碰撞风险。最后用算例验证了模型的可行性,在现行的安全目标水平之下为相关运行部门提供相应的最小安全间距,为实际运行奠定一定的理论基础。     

Treatment of dynamic mixture of hexane and benzene vapors in a Trickle Bed Air Biofilter integrated with cyclic adsorption/desorption beds

One of the main challenges that face successful biofiltration is the erratic loading pattern and long starvation periods. However, such patterns are common in practical applications. In order to provide long-term stable operation of a biofilter under these conditions, a cyclic adsorption/desorption beds system with flow switching was installed prior to a biofilter. Different square waves of a mixture containing n-hexane and benzene at a 2:1 ratio were applied to the cyclic adsorption/desorption beds and then fed to a biofilter. The performance of this integrated system was compared to a biofilter unit receiving the same feed of both VOCs. The cyclic adsorption/desorption beds unit successfully achieved its goal of stabilizing erratic loading even with very sharp peaks at the influent concentration equalizing influent concentrations ranging from 10-470 ppmv for n-hexane to 30-1410 ppmv for benzene. The study included different peak concentrations with durations ranging from 6 to 20 min. The cyclic beds buffered the fluctuating influent load and the followed biofilter had all the time a continuous stable flow. Another advantage achieved by the cyclic adsorption/desorption beds was the uninterrupted feed to the biofilter even during the starvation where there was no influent in the feed. The results of the integrated system with regard to removal efficiency and kinetics are comparable to published results with continuous feed studies at the same loading rates. The removal efficiency for benzene had a minimum of 85% while for n-hexane ranged from 50% to 77% according to the loading rate. The control unit showed very erratic performance highlighting the benefit of the utilization of the cyclic adsorption/desorption beds. The biofilter was more adaptable to concentration changes in benzene than n-hexane.