MESO-α-SCALE CONVECTIVE SYSTEMS OVER CHINA DURING 1995

There were 102 meso-α-scale convective systems(MαCSs)generated over China and theneighboring sea during June—August 1995.Those MαCSs were concentrated in three major areas:the west of South China,Sichuan Basin,and the middle and lower reaches of the Changjiang andthe Huanghe River Basin.Six cases of MαCS in different regions are given to show the variety ofthe MαCS genesis and development by the distributions of their cold-cloud-shield black bodytemperature.     

Analysis of genetic diversity and differentiation of seven stocks of Litopenaeus vannamei using microsatellite markers

Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.     

Evaluating river morphology change with a geomorphic form variation approach

Geomorphic river design strives for natural resilience by encouraging geomorphic form complexity and morphological processes linked to greater habitat diversity. Increasing availability of high-resolution topographic data and spatial feature mapping methods provide advantages for morphological analysis and river restoration planning. We propose and evaluate an approach to quantifying topographic variability of geomorphic form and pixel-level surface roughness resulting from channel planform geometry differences using spatially continuous variety computation applied to component metrics including flow direction, aspect and planform curvature. We define this as the geomorphic form variation (GFV) approach and found it scalable, repeatable and a multi-stage analytical metric for quantifying physical aspects of river-bed topographic variability. GFV may complement process-based morphological feature mapping applications, hydraulic assessment indices and spatial habitat heterogeneity metrics commonly used for ecological quality evaluation and river restoration. The GFV was tested on controlled synthetic channels derived from River Builder software and quasi-controlled sinuous planform flume experiment channels. Component variety metrics respond independently to specific geometric surface changes and are sensitive to multi-scaled morphology change, including coarser-grained sediment distributions of pixel-level surface roughness. GFV showed systematic patterns of change related to the effects of channel geometry, vertical bed feature (pool-bar) frequency and amplitude, and bar size, shape and orientation. Hotspot analysis found that bar margins were major components of topographic complexity, whereas grain-scale variety class maps further supported the multi-stage analytical capability and scalability of the GFV approach. The GFV can provide an overall variety value that may support river restoration decision-making and planning, particularly when geomorphic complexity enhancement is a design objective. Analysing metric variety values with statistically significant hotspot cluster maps and complementary process-based software and mapping applications allows variety correspondence to systematic feature changes to be assessed, providing an analytical approach for river morphology change comparison, channel design and geomorphic process restoration.     

论高岭石粘土和铝土矿研究的新进展

过去我国地质界向前苏联学习,把球粘土(Ballclay)作为高岭土或耐火粘土的一个变种,使我们找矿走入误区,以致后来从美国进口球粘土。其实球粘土的结晶性质这个内在因素与高岭土或耐火粘土常不相同,则派生的性能更不一样,应成为独立的矿种,还可与国际接轨。又过去国内外学者认为高岭石高度有序为热液型的,而沉积型的为无序高岭石。但笔者等的研究,我国高岭石高度有序而规模大且均匀稳定的,应算沉积型的紫矸(古生代高岭石软质粘土),可以作流动性好的造纸涂料。又我国硬水铝石岩溶铝土矿,应属于生物有机质成矿作用的沉积型铝土矿。     

三峡大坝下游溶解氧变化特性及影响因素分析

根据三峡工程坝区水域实测数据,分析了水库蓄水以后大坝上、下游断面溶解氧浓度和溶解氧饱和度的变化特性,探讨了水位、流量因素对大坝下游水体溶解氧量的影响。结果表明,坝身孔口过流水体大量掺气后进入下游河道导致下游水体溶解氧浓度和饱和度显著增加,甚至达到超饱和状态。由于电站过流基本不改变水体溶解氧量,在电站和坝身孔口同时过流时,两种水体掺混后,下游溶解氧量主要受流量比的影响。此外,下游溶解氧量随流量的增加和下游水位的升高而增大。过坝总流量超过35 000 m3/s,下游水位超过68 m以及坝身孔口过流流量占总流量的绝大部分时,需特别重视溶解氧超饱和现象对水生生物可能造成的影响。     

Myosotella myosotis (Mollusca: Ellobiidae) — an overlooked,but well-established introduced species in South Africa

Myosotella myosotis is shown to be a well-established alien species in South Africa. Discovered in Port Elizabeth more than 100 years ago, it was initially thought to be indigenous and was described under two different names, but subsequent taxonomic work has demonstrated that these are synonyms of the variable and widely introduced European M. myosotis. This information, published in a revision of western Atlantic Ellobiidae, has escaped the attention of the South African marine science community. There has been no recent mention of M. myosotis or its two pseudoindigenous synonyms in the literature pertaining to either the estuaries or the malacofauna of South Africa, or to marine bioinvasions in the region. This example serves to demonstrate that invasion biology has a global context and that taxonomic literature is an important source of pertinent data. The fact that a species, which evidently occurs in abundance, can be overlooked for so long is both surprising and sobering.     

Molecular evidence for three separate cryptic introductions of the red seaweed Asparagopsis (Bonnemaisoniales,Rhodophyta) in South Africa

The red seaweed genus Asparagopsis Montagne (Bonnemaisoniales) contains two widely introduced species that are considered notorious seaweed invaders worldwide, Asparagopsis armata and A. taxiformis, both characterised by heteromorphic, diplo-haplontic life histories. To uncover cryptic introductions of Asparagopsis along the South African coastline and identify ‘Falkenbergia’ isolates (i.e. tetrasporophytic life-history phase morphologically identical between species), the mitochon-drial cox2–3 spacer was sequenced from gametophytes of Asparagopsis taxiformis from Scottburgh, KwaZulu-Natal, on the East Coast, Knysna Lagoon on the South Coast and from tetrasporophytes, otherwise unidentifiable to species level, collected from False Bay near Cape Town on the South-West Coast and Tsitsikamma on the South Coast. Only tetrasporophytes of the temperate Asparagopsis armata were encountered from the Cape Peninsula (Cape Town) probably as far east as to Port St Johns, Eastern Cape province. This is considered an introduced species, and was first collected at Kommetjie (Cape Peninsula) in 1935. Gametophytes of the warm-temperate to tropical A. taxiformis were first collected at Reunion Rocks near Durban in 1984; the KwaZulu-Natal material studied here belongs to an Atlantic Mediterranean cryptic lineage. This taxon is an ecological dominant in some intertidal and shallow subtidal areas in northern KwaZulu-Natal, and is thus considered ‘introduced’ and ‘invasive’. In contrast, A. taxiformis gametophytes, collected in Knysna Lagoon in 2008, clustered with individuals of Indo-Pacific lineage 2. The latter is considered a major invasive lineage in the western Mediterranean, but at present is categorised as introduced in South Africa. This study provides molecular evidence of three independent, cryptic introductions in South Africa, one of them probably very recent, and this is discussed with respect to potential vectors responsible for transport.     

辽宁本溪晶花洞碳酸钙沉积物颜色多样性分析

辽宁本溪晶花洞发育于中奥陶统马家沟组(O2m)中厚层白云质灰岩中,洞内碳酸钙沉积物具有白色、黄色、肉红色、浅蓝色和黑褐色等多种原生色彩。在洞穴考察的基础上,通过对围岩和洞穴碳酸钙沉积物X荧光分析以及显微镜薄片鉴定,认为洞穴中白色的次生化学沉积物主要由质纯的CaCO3形成;浅蓝色、黑褐色的形成则多由沉积物含有铜、锶和锰、锌所致;而黄色、红色则为不同环境下铁、锰等变价元素所产生。      

Differential herbivory of invasive algae by native fish in the Mediterranean Sea

The potential role of generalist herbivores to serve as a source of biotic resistance against algal invasion in marine ecosystems has been poorly examined. The present study investigates the capacity of Mediterranean herbivorous fishes to consume three of the most invasive seaweeds of the Western Mediterranean (Caulerpa racemosa, Lophocladia lallemandii and Womersleyella setacea) and examines vertical and temporal variations of such consumption. Our results show that although fish feed throughout the depth gradient examined (5–35 m), they concentrate in shallow waters, and can consume high amounts of C. racemosa. Such high ingestion of C. racemosa does not appear to be random, since this alga is consistently chosen when offered in pairs with several native species. Conversely, L. lallemandii and W. setacea are barely eaten by fish even though they can be very abundant in the field throughout the year. Our results suggest that fish could be an important controlling agent that has been overlooked in temperate marine invasions, and they may be able to provide certain resistance to C. racemosa invasion. In contrast, they are unlikely to exert any important control effects on L. lallemandii or W. setacea.     

西秦岭铅锌矿床的层控多样性与岩相、Ⅱ级构造单元控矿

通过系统归纳西秦岭铅锌矿床的赋矿地层、Ⅱ级构造单元控矿事实认为,矿床的层控多样性在矿田域表现为时控和岩相控矿,层、相、位控矿模式在矿田具有普遍性;在更大的区域上则主要表现为岩相和Ⅱ级构造单元控矿。板内环境下的拉张和陆内叠覆环境下的具走滑性质的俯冲分别形成了热水沉积型和沉积改造型铅锌矿床;沉积成矿期盆地的裂陷程度及改造成矿期沿深断裂活动的岩浆作用决定了铅锌矿床产出的Ⅱ级构造单元。控矿因素的地球化学表征为铁族元素、亲硫元素与亲石元素三位一体产出。