《禹贡》九河分流地域范围新证——兼论古白洋淀的消亡过程

先秦时期黄河下游存在的两大分流，各在其下游段形成九河分流系统，即冀州九河与兖州九河o《尔雅》释九河，实属兖州九河即《汉志》河下游分流水系，在今高唐、黄骅、利津之间。《禹贡》河所播冀州九河，在今深县、黄骅、天津、容城之间。古白洋淀消亡的关键因素是《禹贡》河泥沙的长期堆积，其消亡过程即为《禹贡》河九河的发育过程。     

海洋弧菌鉴定与分类相关功能基因研究进展

【目的】探究功能基因在海洋弧菌物种鉴定中的作用,为海洋弧菌多样性研究以及致病性弧菌的监测和防控提供参考。【方法】根据已有的弧菌分类学研究成果,阐述16S rRNA基因、管家基因和毒力基因等相关功能基因在海洋弧菌鉴定与分类研究中的应用进展。【结果】16S rRNA基因和功能基因可用于海洋弧菌的分类学及其快速检测鉴定的研究,对致病性弧菌的诊治具有重要的意义。【结论】功能基因和16S rRNA基因在海洋弧菌菌种鉴定中的广泛应用,提高了海洋弧菌种间分类的准确性,对海洋弧菌的多样性研究以及水产养殖和人类健康的风险评估有重要价值。探索新型功能基因在海洋弧菌分类学研究和快速鉴定中的应用有现实意义。     

Tidal flow near Mana Island,Cook Strait,New Zealand

Numerical calculations carried out for tidal flow on a small region of the New Zealand coast near Mana Island (41° 5 S, 174° 47 E) solved a finite difference form of the tidal equations, and assumed that the velocity boundary conditions could be approximated by a modified Kelvin wave formula. The results were exponentially smoothed in time at each step in the calculation to remove spurious modes.

The main results are shown as plots of tidal velocity vectors around Mana Island at equally spaced time intervals over a tidal cycle for one run commencing at low tide. The flow becomes very complex, with eddy shedding occurring in the wake of Mana Island, and a tidal rip developing across the shallow connection between Mana Island and the mainland.     

Biological features of Pupu Springs

The flora and fauna of Pupu Springs (40°51'S, 172° 46'E) and five other New Zealand cold springs are described. In Pupu Springs there are 16 species of algae, 10 species of bryophytes (including three species of liverworts), and 5 species of angiosperms. The fauna includes a phreatic form (an eyeless planarian, Dugesia sp.), a possible glacial relict (the caddis fly Rakiura vernale), and cold stenotherms (e.g., the caddis fly Psilochorema tautoru). The most abundant animals in the New Zealand springs are Mollusea, Crustacea, and’ larvae of Plecoptera, Diptera, and Trichoptera.

Pupu Springs consist of five biotopes and associated biocoenoses.     

The use of high temperature gas chromatography to study the biodegradation of high molecular weight hydrocarbons

A consequence of the biodegradation of petroleum is that lower molecular weight compounds are removed preferentially to higher molecular weight (HMW) compounds greater than triacontane (n-C₃₀). The extent to which the latter compounds are biodegraded has rarely been studied. Reasons for this include the technical difficulties associated with carrying out biodegradability tests with solid, water-insoluble substances and the limits of the analytical techniques, such as gas chromatography (GC).A quantitative high temperature GC (HTGC) method was developed to monitor the biodegradation of the aliphatic fraction of a waxy Indonesian oil by Pseudomonas fluorescens. Recoveries of over 90% were obtained for n-alkanes up to hexacontane (C₆₀) using liquid-liquid continuous extraction. After only 14 days, 80% of the aliphatic hydrocarbons had been degraded. At the end of the 136-day study, 14% of the original fraction remained. This comprised mainly C₄₀₊ compounds. No decrease in the concentrations of compounds above C₄₅ was observed. However, the use of a rapid screening biodegradation method provided tentative proof that Pseudomonas fluorescens was capable of utilising n-alkanes up to C₆₀ once the bacteria had acclimated to HMW alkanes.     

应用黄金分割法优选小球藻的培养温度

利用黄金分割(0.618)优选法测定了两株分离自海南近岸海域的小球藻(Chlorella spp.)的最适生长温度。结果表明,黄金分割优选法可以较少的实验次数找到小球藻的最适培养温度。两株小球藻在15～40℃温度范围内均可生长。小球藻HNC11的最适生长温度为34～36.5℃;小球藻HNC2的最适生长温度为28～30.5℃左右。     

Within‐Site Variation in Lichen Growth Rates and Its Implications for Direct Lichenometry

Variation in lichen growth rates poses a significant challenge for the application of direct lichenometry, i.e. the construction of lichen dating curves from direct measurement of growth rates. To examine the magnitude and possible causes of within‐site growth variation, radial growth rates (RaGRs) of thalli of the fast‐growing foliose lichen Melanelia fuliginosa ssp. fuliginosa (Fr. ex Duby) Essl. and the slow‐growing crustose lichen Rhizocarpon geographicum (L.) DC. were studied on two S‐facing slate rock surfaces in north Wales, UK using digital photography and an image analysis system (Image‐J). RaGRs of M. fuliginosa ssp. fuliginosa varied from 0.44 to 2.63 mm yr^–1 and R. geographicum from 0.10 to 1.50 mm yr^–1.5. Analysis of variance suggested no significant variation in RaGRs with vertical or horizontal location on the rock, thallus diameter, aspect, slope, light intensity, rock porosity, rock surface texture, distance to nearest lichen neighbour or distance to vegetation on the rock surface. The frequency distribution of RaGR did not deviate from a normal distribution. It was concluded that despite considerable growth rate variation in both species studied, growth curves could be constructed with sufficient precision to be useful for direct lichenometry.     

SIMULTANEOUS ESTIMATES OF SYNECHOCOCCUS SPP. GROWTH AND GRAZING MORTALITY RATES IN THE ENGLISH CHANNEL

The marine chroococcoid phycoerythrin-containing Synechococcus spp.cyanobacterium has been impli-cated as a subsetantial component of the photosynthetic picoplankton in the ocean. Although its imppr-tance as food source for heterotrophic nanoplankton is now recognized, information about the cycling ofSynechococcus biomass and its diel pattern is limited and study methodology varies among authors. Theselective metabolic inhibitor method was used to simultaneously estimate growth and grazing disappearancerates of Synechococcus in the English Channel where growth rates ranged from 0.25 to 0.72/d (mean±SD=0.51±0.17/d) and grazing mortality rates ranged from 0.19 to 0.64/d (mean ±SD=0.48±0.17/d).Size-fractionated experiments demonstrated that up to 70% of Synechosoccus disappearance could be attri-buted to grazers going through a 2 μm Nuclepore filter. Synechococcus grazing mortality rates (mean=0.74±0.25/d) during the day were alwnys higher than that (mean=0.21±0.20d) during the night, while growthrat     

播种深度和土壤水分对黄花补血草种子萌发的影响

 采集来自腾格里沙漠的黄花补血草种子,分别设置7个水分梯度（3.0%, 5.0%, 8.0%, 10.0%, 15.0%,18.0%,20%) 和6个播种深度（0、0.5、1.0、1.5、2.0、2.5 cm）,进行黑暗（10～15 ℃）和光照(20～25 ℃)处理,研究水分、埋藏深度和温度对黄花补血草种子萌发和出苗的影响。结果表明：黄花补血草种子吸涨速率很快,在6 h种子吸水达到饱和;在土壤水分为3.0%～10.0%时,种子萌发率较高,当土壤水分达到20%时,萌发受到抑制;种子埋藏越深,萌发率越低,土壤水分太低或者太高,都不利于种子萌发。黄花补血草种子萌发和幼苗生长的最佳条件是：白天温度在25 ℃,夜间温度在15 ℃,土壤水分为10.0%,埋藏深度为0.5 cm时种子萌发率和出苗率最高。