Utilization of emergent plants as an aestivation habitat by the Trapa-feeding leaf beetle (Galerucella nipponensis) in Lake Inba,Japan

Limnology - Water chestnuts (Trapa spp.) dominate many shallow eutrophic lakes, and impact aquatic fauna. Use of Trapa beds by animals may vary with the growth stage of Trapa, but little is known...     

黑龙江和图们江流域菱属(Trapa L.)植物分布格局及形态多样性

菱属(Trapa L.)的系统分类一直存在较大分歧,至今还没有一个比较公认的分类系统。黑龙江和图们江流域是菱属物种多样性的重要分布区之一,为了揭示该流域菱属植物的地理分布格局和形态多样性,我们进行了大量实地调查和研究。结果显示,从该地区28个湖中共采集到菱属11个种及8个种内变异类型,表明它们具有丰富的形态多样性;结合查阅菱属354份标本资料,共获得92个分布地点数据;采集到的11个物种的地理分布格局呈不均衡性,其中细果野菱(Trapa maximowiczii Korsch.)分布最广,野菱(Trapa incisa Siebold et Zucc.)、兴凯菱(Trapa khankensis Pshennikova)和科热夫尼科夫菱(Trapa kozhevnikovirum Pshennikova)为狭域分布种;东部乌苏里江和图们江流域是菱属物种多样性的分布中心,可能是第四纪冰期避难所;菱属植物多数种间形态特性相对稳定,东北菱(Trapa manshurica Fler.)、耳菱(Trapa potaninii V.Vassil)、丘角菱(Trapa japonica Fler.)、西伯利亚菱(Trapa sibirica Fler.)和细果野菱共有8个种内形态变异类型;种群内多数分类性状稳定,种群间形态变异较明显;菱属植物分布格局不均衡和种内形态变异的形成可能与基因流的扩散限制有关。本研究结果为进一步澄清菱属分类混乱问题奠定了基础,进一步结合分子标记技术研究系统演化关系将对揭示菱属的进化历史具有重要意义。     

鄂东花马潮水生高等植物研究——Ⅱ.水生植被

花马湖位于湖北省鄂州市境内,面积约27.5km~2。湖中分布有水生高等植物82种2变种。花马湖水生植被可分为15个群丛,其中菱群丛、竹叶眼子菜群丛、金鱼藻+狐尾藻+菹草+苦草群丛较为重要。湖中水生植波呈不规则的环带状分布,并可划分为湿生、挺水、浮叶和沉水4个植被带,各带均有相应的群丛分布。     

菱属野生植物形态学性状的可塑性变异及其分类学价值

长江中下游平原和东北三江平原是我国最大的两个冲积平原,其内河流、浅水湖泊和沼泽众多,菱属植物种类丰富。本研究基于对这两个区域中菱属野生植物的广泛调查,采集其居群42个,分属于9种(细果野菱、四角刻叶菱、四角菱、菱、丘角菱、东北菱、四角大柄菱、八瘤菱、四瘤菱),3变种(四角矮菱、南昌格菱、短四角菱)。进一步对采集的菱属野生植物16个分类性状进行测量和统计,并对其形态学性状的可塑性变异及分类学价值进行分析和评价。结果显示:依据菱角的果体大小、果喙性状可以将采集的菱属野生植物划分成两个类群,其中A类群仅包括细果野菱和四角刻叶菱,而其余的菱属植物7种3变种组成B类群;对有腰角组(5种2变种)的腰角性状进行聚类分析,也可将细果野菱和四角刻叶菱与其他菱属植物区分开来;而瘤突、叶和气囊性状的分类价值有限。说明果体大小、果喙和腰角性状的形态学特征是菱属植物分类和鉴定的主要依据。     

Scaled chrysophytes (Chrysophyceae and Synurophyceae) from national park lakes in southern and central Finland

A total of 34 scaled chrysophyte taxa (18 Mallomonas spp., 6 Synura spp., 2 Chrysosphaerella spp., 6 Spiniferomonas spp. and 2 Paraphysomonas spp.) were recorded by SEM techniques in 61 samples from 59 lakes locating in 8 national parks of southern and central Finland in July 1987. Most of the lakes were small forest and peat bog lakes with acid (pH 4.6–7.2) and soft-water and with variable water colour (10–350 mg Pt/l). The number of taxa per lake varied from 0 to 15 and it correlated very significantly with the water pH. The species structure was rather typical for the oligotrophic and acid lakes. Besides the eurytypic and common species like Mallomonus caudata (fr. 72.1% of lakes), M. crassisquama (65.6%), M. allorgei (62.3%) and M. akrokomos (52.5%) also M. canina (41.0%) and M. hamata (21.3%) were frequently observed. M. calceolus, M. costata, M. papillosa, M. pugio and M. paludosa were more rare but typical for acid lakes. Synuru splendida which occurred in two lakes was the most rare and a new species for Finland.     

Bacterial composition of sponges,sediment and seawater in enclosed and open marine lakes in Ha Long Bay Vietnam

ABSTRACT

Marine lakes are landlocked bodies of seawater, isolated to varying degrees from the surrounding marine habitat. Isolated lakes generally have lower pH values, salinities and higher temperatures than more open lakes. We used a 16S rRNA gene barcoded pyrosequencing approach to study the bacterial communities of two sponge species, sediment and seawater in one enclosed and two open marine lakes. Bacterial communities of the sponge Spheciospongia solida mainly consisted of Proteobacteria, Cyanobacteria and Bacteroidetes. In contrast, Proteobacteria, Chloroflexi and Acidobacteria dominated the bacterial communities of the sponge Spongia ceylonensis. Although only a limited amount of samples were collected, both water and S. ceylonensis sponge had higher relative abundances of Cyanobacteria in the enclosed lake, which mainly consisted of OTUs assigned to the genus Synechococcus. This is in line with a number of previous studies, which have shown that environmental conditions found within low pH environments such as marine lakes benefit the growth of Synechococcus spp. Future studies should address the mechanism by which Synechococcus spp. may help host sponges and their bacterial communities adapt to low pH conditions in isolated marine lakes and other low-pH environments.     

Communities of metazoan parasites in open water fishes of Cold Lake, Alberta

Communities of metazoan parasites in ten species of fishes from Cold Lake, Alberta are described and compared. Relative abundances in the overall community of parasites in the lake were estimated using data on abundance in each host species, plus estimates of the relative abundances of the species of hosts. Parasites of the numerically dominant salmonid fishes dominated the overall community, with over half of the individual parasites being Metechinorhynchus salmonis . Exchange of parasites between host species was greatest between related and/or abundant host species. Parasite communities in cisco and whitefish, Coregonus spp., were relatively rich in species and diverse (Simpson's index) compared with communities in those species in other lakes in North America; communities in lake trout, Salvelinus spp., and the non-salmonid fishes were poor in species and low in diversity compared with communities in other lakes. Parasite species overlaps (Jaccard index) between related host species in Cold Lake were greater than overlaps within host species between lakes. The same pattern is seen in data from some other lakes. These features support the hypothesis of Wisiewski (1958); that the parasite community within an ecosystem is characterized by parasites of the numerically dominant hosts.     

洞庭湖区三个湖泊水生植物多样性的比较研究

比较研究了洞庭湖区华容县东湖、益阳市大通湖和岳阳市郊南湖水生植物多样性的现状,讨论了30年来3个湖泊水生植物多样性丧失的情况及与其所受人为干扰的关系,探讨了野菱、密齿苦草和菹草对人为干扰的适应机制、大通湖和南湖水生植物多样性及其退化水生态系统恢复的途径。主要结论如下：（1）199－2000年东湖、大通湖与南湖各分布有水生植物61种、56种和32种,其分别隶属于29科43属、26科39属和20科27属;各有水生植物群丛8个、6个和4个;水生植被覆盖率分别为26．17％、10．60％和9．99％。（2）30年来三个湖泊分别有3种、9种和13种水生植物消失,2个、5个和5个水生植物群丛类型消失。（3）水生植物多样性的现状是：东湖＞大通湖＞南湖,多样性下降的程度与其所受干扰强度成正相关。     

Lake acidity,fish predation,and the distribution and abundance of some littoral insects

Densities of Corixidae (Hemiptera), larval Odonata, and large larval Trichoptera were estimated in the littoral zone of small lakes in an acid-stressed area near Sudbury, Ontario. Fish were present in some lakes and absent in others, and fishless lakes occurred across a wide range of pH. Corixidae were significantly more abundant in lakes without fish than in lakes with fish, and their numbers were not related to the pH of fishless lakes. Anisoptera (Odonata) larvae tended to be more numerous in benthic samples from fishless lakes than from lakes with fish, and their exuviae were significantly more abundant around fishless lakes. In most lakes, the assemblage was dominated by three species; Leucorrhinia glacialis, Libellula julia, and Cordulia shurtleffi. In lakes containing white sucker, Catostomus commersoni, Gomphus spp. were most numerous. In the most acid fishless lakes, L. julia was uncommon, and L. glacialis was extremely abundant. In fishless lakes, numbers of Anisoptera larvae and exuviae were negatively correlated with pH, though species richness was positively correlated with pH. Exuviae of Zygoptera (Odonata) were more abundant around fishless lakes, irrespective of pH. Larvae of Limnephilus (Trichoptera) were most abundant in non-acid fishless lakes, and absent at pH<5.2. Abundances of Banksiola (Trichoptera) were negatively correlated with the pH of fishless lakes.     

Saline lakes of the Paroo,inland New South Wales,Australia

Twenty-five lakes from fresh to crystallizing brine in the semi-desert of northwestern New South Wales, Australia, were studied regularly for 27 months. The lakes are small, shallow and ephemeral. Chemically waters are mainly of the NaCl type. Seventy-four species of invertebrate occur in saline waters (>3 g l^–1) with crustaceans such as Parartemia minuta, Apocyclops dengizicus, Daphniopsis queenslandensis, Diacypris spp. and Reticypris spp. dominant, particularly at higher salinities. The insects Tanytarsus barbitarsis and Berosus munitipennis are also important in meso- and hypersaline lakes. They are joined in hypo- and mesosaline waters by many others, including more beetles, odonatans, trichopterans, pyralids, notonectids, and corixids. Species richness declines with increasing salinity. There is a prominent inland faunal component mainly of crustaceans, including P. minuta, D. queenslandensis, R. walbu, Trigonocypris globulosa and Moina baylyi.     

鄱阳湖水生植被

本文列出了鄱阳湖98种水生维管束植物的名录,叙述了水生植被的分布。鄱阳湖水生植被面积为2262平方公里,占全湖总面积的80．8％。湖中植被呈不规则环带状分布,并可划分为湿生、挺水、浮叶和沉水4个植物带,9个主要植物群丛。并研究了鄱阳湖水生植被的演变及发展趋势和湖水位的季节性变化对植被的影响。     

Campylobacter spp., Giardia spp., Cryptosporidium spp., noroviruses, and indicator organisms in surface water in southwestern Finland, 2000-2001

A total of 139 surface water samples from seven lakes and 15 rivers in southwestern Finland were analyzed during five consecutive seasons from autumn 2000 to autumn 2001 for the presence of various enteropathogens (Campylobacter spp., Giardia spp., Cryptosporidium spp., and noroviruses) and fecal indicators (thermotolerant coliforms, Escherichia coli, Clostridium perfringens, and F-RNA bacteriophages) and for physicochemical parameters (turbidity and temperature); this was the first such systematic study. Altogether, 41.0% (57 of 139) of the samples were positive for at least one of the pathogens; 17.3% were positive for Campylobacter spp. (45.8% of the positive samples contained Campylobacter jejuni, 25.0% contained Campylobacter lari, 4.2% contained Campylobacter coli, and 25.0% contained Campylobacter isolates that were not identified), 13.7% were positive for Giardia spp., 10.1% were positive for Cryptosporidium spp., and 9.4% were positive for noroviruses (23.0% of the positive samples contained genogroup I and 77.0% contained genogroup II). The samples were positive for enteropathogens significantly (P < 0.05) less frequently during the winter season than during the other sampling seasons. No significant differences in the prevalence of enteropathogens were found when rivers and lakes were compared. The presence of thermotolerant coliforms, E. coli, and C. perfringens had significant bivariate nonparametric Spearman's rank order correlation coefficients (P < 0.001) with samples that were positive for one or more of the pathogens analyzed. The absence of these indicators in a logistic regression model was found to have significant predictive value (odds ratios, 1.15 x 10(8), 7.57, and 2.74, respectively; P < 0.05) for a sample that was negative for the pathogens analyzed. There were no significant correlations between counts or count levels for thermotolerant coliforms or E. coli or the presence of F-RNA phages and pathogens in the samples analyzed.     

大理西湖流域开发历史与硅藻群落变化的模式识别

有关云南湖泊的研究长期集中于高原九大湖泊和水体富营养化评价,缺少对中小型水体及多重环境压力胁迫的综合研究.本文以大理西湖为例,结合沉积物记录与现代监测资料,甄别了气候变化和人类活动干扰下硅藻群落结构的长期响应模式及其驱动强度.结果表明: 20世纪50年代以前,大理西湖总体处于自然演化阶段;1950年代开始,围湖造田和流域改造的增强导致了水体营养水平增加、水动力条件改变,硅藻优势种由扁圆卵型藻替代为脆杆藻属;而1997年以来营养水平的快速增加和湖泊水动力的改变,促进了浮游藻类大量生长、底栖硅藻持续减少,同时水生植物快速退化、生态系统稳定性明显降低.因此,在长期流域开发的背景下,对云南中小型高山湖泊的有效保护需要评价流域开发类型、强度及全球变暖的长期影响.     

中国东北菱属植物的研究

本文讨论了东北地区菱属的分类学问题,诸如分类等级、性状判定、定种依据和同物异名等。因中国东北是菱属植物的重要分化中心,对此区菱属植物的深入研究无疑会为菱属的分类等方面提供有力的佐证。     

Cyprinid assemblages,and the physical and chemical characteristics of small northern Ontario lakes

Synopsis The cyprinid species, and physical and chemical characteristics were recorded from 58 small lakes in the Algoma district of northern Ontario. A group of typical stream-dwelling lithophilous species, which included common shiner, Notropis cornutus, creek chub, Semotilus atromaculatus, and blacknose dace, Rhinichthys atratulus, tended to occupy lakes of larger than average drainage areas. Phoxinus spp., pearl dace, Semotilus margarita, and fathead minnow, Pimephales promelas, occurred commonly in lakes with small drainage areas, and the average drainage area of lakes they occupied was near or below the overall average. Lakes without stream cyprinids were discriminated from lakes with them on a combination of chemical variables, including pH, alkalinity and calcium, which indicated that they were more susceptible to anthropogenic acidification.     

Benthic communities of exposed littoral sand-flats in eighteen Dutch lakes

Benthic communities of the exposed sandy littoral zone in eighteen Dutch lakes were sampled using a small, hand-held core (surface area 0.8 cm²). A community dominated by chironomid larvae, chydorid cladocerans, nematodes and copepods was found to be characteristic for this habitat, especially in large and/or deep lakes. Bray-Curtis similarities between sites were generally high (>70%). A hierarchical cluster analysis distinguished two clusters at a 75% similarity level only, varying in copepod and chydorid densities. The chironomidsCladotanytarsus andStictochironomus reached high densities in many lakes, whileRhynchotalona falcata, Monospilus dispar, Disparalona rostrata, Alona spp. andChydorus spp. (mainlyChydorus piger) were the most abundant chydorid taxa.     

Limnological characteristics of subtropical Lakes Phewa, Begnas, and Rupa in Pokhara Valley, Nepal

Limnological characteristics were studied and analyzed in the subtropical Lakes Phewa, Begnas, and Rupa of Pokhara Valley, Nepal, from 1993 to 1997. The annual water temperature ranged from 12° to 29°C in all lakes. Lake Phewa and Lake Begnas were monomictic and anoxic in the hypolimnion during thermal stratification from April to September. Dissolved oxygen was drastically depleted in April and/or May in shallow Lake Rupa when the macrophyte community began to decompose. NH₄ ⁺-N accumulated below 5 m during March–September when dissolved oxygen was depleted in Lakes Phewa and Begnas. The PC : PP ratio was higher, but the PC : PN and PN : PP ratios were close to the Redfield ratio (106C : 16N : 1P) in Lakes Phewa and Begnas, denoting that P was limited. Annual net primary production showed that the lakes were productive but will tend to become heterotrophic in the future. The seasonal variation of chlorophyll a concentration was high, but its annual variation was low. Ceratium hirundinella and Peridinium spp. in Lake Phewa, Microcystis aeruginosa and Aulacoseira granulata in Lake Begnas, and Tabellaria fenestra in Lake Rupa were the dominant species. The zooplankton population and species varied irregularly. On the basis of chlorophyll a concentration in the euphotic zone and phytoplankton species composition, the lakes seem to be oligoeutrophic and to have some characteristics of temperate lakes rather than tropical lakes. Received: April 26, 1999 / Accepted: September 20, 1999     

The diatom flora and limnology of lakes in the Amery Oasis,East Antarctica

The diatom flora of three lakes in the ice-free Amery Oasis, East Antarctica, was studied. Two of the lakes are meltwater reservoirs, Terrasovoje Lake (31 m depth) and Radok Lake (362 m depth), while Beaver Lake (>435 m depth) is an epishelf lake. The lakes can be characterized as cold, ultra-oligotrophic and alkaline, displaying moderate (Radok and Terrasovoje lakes) to high (Beaver Lake) conductivities. There was no diatom phytoplankton present in any of the three lakes. While 34 benthic diatom taxa were identified from modern and Holocene sediments of Terrasovoje and Radok lakes, a 30-cm long sediment core recovered in Beaver Lake was barren. Five species (Luticola muticopsis, Muelleria peraustralis, Pinnularia cymatopleura, Psammothidium metakryophilum, P. stauroneioides) are endemic to the Antarctic region. All identified taxa are photographically documented and brief notes on their taxonomy, biogeography and ecology are provided. The most abundant diatom taxa are Amphora veneta, Craticula cf. molesta, Diadesmis spp, M. peraustralis and Stauroneis anceps. This is the first report on the diatom flora in lakes of the Amery Oasis.This revised version was published online in May 2004 with corrections to Figure 1.     

Macrophytes from lakes in the eastern Pyrenees: community composition and ordination in relation to environmental factors

1. Thirty-six species of macrophytes (fourteen flowering plants, two quillworts, sixteen mosses and liverworts, and two algae) were collected in an extensive survey of 116 high mountain lakes in the eastern Pyrenees. Seventy per cent of the lakes showed macrophyte development. 2. The isoetids (Isoetes lacusiris, Isoetes setacea and Subularia aquatica) were the dominant growth form, although the natopotamid Sparganium angusifolium was the most widespread species. Potamids (Potamogeton spp., Ranunculus spp.), the alga Nitella gr. opaca and some mosses (Warnstorfia exannulata, Sphagnum denticulatum) were often present. 3. A multivariate ordination analysis (RDA-redundancy analysis) revealed that water chemistry, altitude and vegetation cover of the catchment, and nutrient availability are major environmental factors associated with macrophyte distribution along the eastern Pyrenean lakes. Isoetids prevailed in softwater oligotrophic lakes, potamids in relatively hardwater oligotrophic lakes, and Potamogeton natans and Callitriche palustris in small and eutrophic water bodies affected by the presence of cattle.