黑龙江省七星河湿地硅藻植物的初步研究

报道了2004年对黑龙江省七星河湿地国家级自然保护区的硅藻门植物研究的结果,共发现155个分类单位,包括113种39变种3变型,分别隶属于2纲6目9科26属,其中中国新记录2种2变种1变型共计5个分类单位,初步分析了七星河湿地硅藻植物群落的种类组成及生态类型,大部分的硅藻属于普生种类,同时出现了一些喜酸种类如：Eunotia pectinalis var. ventralis(Ehr.)Hust., Tabellaria flocculosa(Roth) Kütz.,Gomphonema augur Ehr.,Navicula subtilissima Cl.等,还有少量的嗜碱性种类出现。     

PHYSIOLOGICAL MODIFICATIONS RELATED TO DENSITY INCREASE IN PERIPHYTIC ASSEMBLAGES 1

Periphytic communities in running waters were examined as they developed on granite rocks, concrete balls and glass slides. At equivalent cell densities, no differences in pigment concentrations, species diversity or production levels were found among the different substrata examined. Development of the assemblage appeared to result from the elongation of short algal filaments which had initially settled on the surface. As these communities matured, a distinct canopy and understory developed. Cellular metabolisms were comparable among the communities. In the understory of the communities, even though the cellular content of chl a and b did not differ, chl c and carotenoid pigment concentrations were higher than those in the over-story. Bicarbonate assimilation of Tabellaria fenestrata (Lyng.) Külz. and Eunotia pectinalisi var. pectinalis (O. F. Müll?) Rabh. was higher than that of the more abundant Tabellaria flocculosa (Roth.)Kütz. var. flocculosa IV (sensu Koppen) at both high and low cell densities. This probably reflects a seasonal succession of colonizing species. Glucose assimilation appeared to be mainly attributable to bacterial activity, and algal cells of the upper layer were less active than those of the bottom. The small amount of glucose that was incorporated by the algal cells was probably absorbed passively since its amount was in direct proportion to cell volumes.     

PERIPHYTON COLONIZATION OF ROCK SURFACES IN A BOREAL FOREST STREAM STUDIED BY SCANNING ELECTRON MICROSCOPY AND TRACK AUTORADIOGRAPHY1

Periphyton colonization of natural rock surfaces and granite tiles was followed experimentally in the Matamek River, an acidic (pH 5.5) sixth order boreal stream in northeast Quebec, Canada. Accumulation of chlorophyll a and freshweight algal biomass was logarithmic over a 25 day colonization period. The major colonizers were Tabellaria flocculosa (Roth) Kütz., T. fenestrata (Lyngb.) Kütz., Mougeotia sp., and Eunotia pectinalis (Kütz) Rabh., and its varieties. The microcolonization sequence on granite tiles, followed over 27 days with scanning electron microscopy, showed an initial accumulation of algal cells on the upstream and downstream margins and in depressions, followed by a gradual filling-in of the flat surfaces. It is hypothesized that the observed slow rate of colonization was due to the high surface tension of the granite substratum and the absence of preconditioning by an organic film. It is further hypothesized that the increase in cellular carbon fixation rates of T. flocculosa measured over a 23 day period using nuclear track autoradiography parallels the development of an algal-detrital microcosm on the granite tile, and is evidence for the establishment of localized tight nutrient spiralling. It is suggested that the periphyton community may be regarded as a nutrient recycling system at a microenvironmental level which may be especially important in oligotrophic systems.     

Distribution and diversity of diatom assemblages in surficial sediments of shallow lakes in Wapusk National Park (Manitoba,Canada) region of the Hudson Bay Lowlands

The hydrology of shallow lakes (and ponds) located in the western Hudson Bay Lowlands (HBL) is sensitive to climate warming and associated permafrost thaw. However, their biological characteristics are poorly known, which hampers effective aquatic ecosystem monitoring. Located in northern Manitoba along the southwestern coast of Hudson Bay, Wapusk National Park (WNP) encompasses numerous shallow lakes representative of the subarctic zone. We analyzed the distribution and diversity of diatom (microscopic algae; class Bacillariophyceae) assemblages in surficial sediments of 33 lakes located in three different ecozones spanning a vegetation gradient, from NE to SW: the Coastal Fen (CF), the Interior Peat Plateau (IPP), and the Boreal Spruce Forest (BSF). We found significant differences (P < 0.05) in diatom community composition between CF and IPP lakes, and CF and BSF lakes, but not between IPP and BSF lakes. These results are consistent with water chemistry measurements, which indicated distinct limnological conditions for CF lakes. Diatom communities in CF lakes were generally dominated by alkaliphilous taxa typical of waters with medium to high conductivity, such as Nitzschia denticula. In contrast, several IPP and BSF lakes were dominated by acidophilous and circumneutral diatom taxa with preference for low conductivity (e.g., Tabellaria flocculosa, Eunotia mucophila, E. necompacta var. vixcompacta). This exploratory survey provides a first detailed inventory of the diatom assemblages in the WNP region needed for monitoring programs to detect changes in shallow lake ecosystems and ecozonal shifts in response to climate variations.     

Comparing the responses of diatoms and macro- invertebrates to metals in upland streams of Wales and Cornwall

SUMMARY 1. Surprisingly few data compare the apparent responses of diatoms and macroinvertebrates to metals in streams. We examined variation in metals, diatoms and macroinvertebrates between 51 streams in metal‐mining areas of Wales and Cornwall, U.K., using a survey design with multiple reference and polluted sites. 2. To quantify variations in metals between sites, we calculated cumulative criterion unit (CCU) scores, a recently defined measure of total stream metal concentration and toxicity, to account for additive effects of each metal relative to putative toxic thresholds. We compared assemblage responses among epilithic diatoms and macroinvertebrates to CCU scores or individual metal concentrations using correlation and detrended correspondence analysis (DCA). 3. Macroinvertebrate diversity, richness and total abundance declined and evenness increased with increasing copper concentrations. Trends with CCU scores were significant but less pronounced. Some individual macroinvertebrate taxa varied significantly in abundance with CCU scores, copper or zinc, but overall assemblage composition correlated only with manganese, pH and nitrate. 4. Among diatoms, pH and conductivity explained the major variations in assemblage composition, and neither diversity, richness nor evenness varied with metal concentration. Nevertheless, the single strongest predictor of diatom assemblages on ordination axis 2 was the CCU score. The abundances of some macroinvertebrate taxa, particularly grazers, also explained significant variations in diatom assemblages that were linked to both metals and acid–base status. 5. Diatom species apparently tolerant of high metal concentrations included Psammothidium helveticum, Eunotia subarcuatoides, Pinnularia subcapitata and Sellaphora seminulum. Of these, P. helveticum, E. subarcuatoides and P. subcapitata were abundant at lower pH than S.seminulum and might indicate metal enrichment over different pH ranges. Sensitive species included Fragilaria capucina var. rumpens, Achnanthes oblongella and Tabellaria flocculosa. 6. We conclude that macroinvertebrates at these sites reflected metal pollution most strongly through variations in diversity while effects on diatoms were best reflected by changes in assemblage composition. We suggest that, with further refinement, CCU scores might be useful in evaluating the possible effects of metal pollution on benthic organisms in European rivers.     

Phytoplankton successions under ice cover in four lakes located in North-Eastern Sweden: Effects of liming

Phytoplankton successions under ice cover (January–March) were determined in four oligotrophic lakes (Burtjärn, Aspen, Vialamptjärn and Storkorstjärn) located in North-Eastern Sweden. The total phosphorus concentration in the lakes was less than 10 µg/L. Lake Burtjärn (reference lake) had a similar hydrology as Lake Aspen. Storkorstjärn and Vialamptjärn were of similar hydrology and had heavily colored water (>100 mg_Pt/L). Aspen as well as Vialamptjärn became continuously limed with calcium carbonate annually during the last decades. Biodiversity was considerably higher in the limed lakes (Aspen and Vialamptjärn) than in the untreated lakes (Burtjärn and Storkorstjärn). In Lake Burtjärn the most frequent species wereRhodomonas lacustris, Tabellaria flocculosa andBotryococcus braunii. Cryptophyceae (R. lacustris andCryptomonas marssonii) andDinophyceae (especiallyGymnodinium lantzschii) were common phytoplankton groups in Lake Aspen.Tabellaria flocculosa was also the most common organism in both humic lakes Storkorstjärn and Vialamptjärn, other phytoplankton groups were in the humic lakes scarce. Liming was found to have profound effects on phytoplankton communities studied.     

Bewegungs- und Teilungsverhalten der Chromatophoren vonEunotia pectinalis var.polyplastidica und andererEunotia-Arten bei der Zellteilung

Summary The correlation between the start of chromatophore division and cell division is very different in various species ofEunotia. In some species the chromatophore division occurs before, in others after cell division. Eunotia pectinalis var.polyplastidica, with eight chromatophores per cell, represents an extreme type of behaviour in so far as two of the four plastids in each daughter cell prior to their division are shifted to the new hypovalve while the other two rest in situ. There occur two patterns of distribution of the four plastids, and that in the ratio 11, whereas the theoretically possible third pattern is never realized. The cause of that phenomenon is discussed. The division of the four plastids, in the meantime grown to full size, is performed not before they have reached their definitive equilibrium position at the epivalve or, respectively, at the hypovalve in twos. InEunotia pectinalis var.polyplastidica, by its mode of chromatophore division, the constant dissymmetric (right-left-handed) arrangement of the growing chromatophores, established inEunotia arcus, is not to be expected and is in fact not realized. InEunotia lunaris, however, the shift of the daughter chromatophores, in relation to the dorsiventrality of the cell, shows not only the same kind of dissymmetry as inEunotia arcus but also the same direction of shifting.The four and four chromatophores inEunotia pectinalis var.polyplastidica correspond to the two chromatophore plates in other species but the are not comparable with the numerous little chromatophore discs of Diatomaceae and other species the number of which decreases with the reduction of cell size.Cells ofEunotia pectinalis var.polyplastidica are capable to move by raphe action.

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Herrn Dr.Franz Berger zum 70. Geburtstag gewidmet.     

The Effect of Fish Introductions on the Diatom and Cladoceran Communities of Lake Opeongo,Ontario, Canada

Fish introductions are one of the most widespread anthropogenic perturbations to aquatic ecosystems. Paradoxically, the effects of these introductions on aquatic ecosystems are typically poorly documented. This project studied the effect of fish introductions on Lake Opeongo, an oligotrophic lake in Algonquin Provincial Park, Ontario, Canada (45° 42′ N, 78° 22′ W), using the remains of algae (diatoms) and zooplankton (cladocerans) preserved in the sediments. It was hypothesized that the introduction of cisco or lake herring (Coregonus artedii Lesueur) in 1948, which filled the underutilized pelagic forage fish niche, should have altered nutrient availability for phytoplankton. Prior to cisco introduction, the diatom community of Lake Opeongo reflected a relatively stable oligotrophic state established before European settlement, and consisted of the Cyclotella stelligera complex with subdominants Tabellaria flocculosa IIIp and the Aulacoseira distans complex. No marked changes occurred until ca. 1962 when the diatom community shifted to an assemblage with increased total phosphorus preferences, consisting of Asterionella formosa and lesser amounts of Cyclotella bodanica var lemanica, the C. stelligera complex, Fragilaria crotonensis and T. flocculosa IIIp. The dominant cladoceran Bosmina longirostris increased significantly in relative abundance since the introduction of cisco. The most likely cause of this shift was increased nutrient recycling and/or trophic level changes caused by human manipulation of the fish community of the lake.     

RELATIONSHIPS OF SEDIMENTED DIATOM SPECIES (BACILLARIOPHYCEAE) TO ENVIRONMENTAL GRADIENTS IN DILUTE NORTHERN NEW ENGLAND LAKES1

Limnological gradients of small, oligotrophic, and low conductance lakes in northern New England were defined by principal components analysis; relationships of sedimented diatom species to the gradients were investigated by correlation analysis. Diatom distributions were most strongly related to the gradient of pH and alkalinity and the covarying variables, conductance, Mg, Ca, total Al, and exchangeable Al. Weaker relationships to lake morphology, dissolved organic carbon and water color, altitude and marine aerosol inputs, and the distinctive water chemistry of some New Hampshire lakes were also present. Results for 16 taxa of importance in our studies of lake acidity are given in detail and are compared to results from other regions of eastern North America. Planktonic taxa were absent below pH 5.5, with the exception of the long form of Asterionella ralfsii var. americana Korn. The two forms of this taxon differed ecologically: the long form (>45μm) had an abundance weighted mean (AWM) pH 4.90 and occurred mostly in lakes that were deep relative to transparency; the short form (<45μm)had an AWM pH and occurred on lakes that were shallow relative to transparency. The ecological advantage of a “splitter” approach to diatom taxonomy was demonstrated by examination of other taxa as well, including Tabellaria flocculosa (Roth) Kütz. These results have important implications for paleolimnological interpretations.     

SEVA 3.1: enabling interoperability of DNA assembly among the SEVA,BioBricks and Type IIS restriction enzyme standards

Robust synthetic biology applications rely heavily on the design and assembly of DNA parts with specific functionalities based on engineering principles. However, the assembly standards adopted by different communities vary considerably, thus limiting the interoperability of parts, vectors and methods. We hereby introduce the SEVA 3.1 platform consisting of the SEVA 3.1 vectors and the Golden Gate-based ‘SevaBrick Assembly’. This platform enables the convergence of standard processes between the SEVA platform, the BioBricks and the Type IIs-mediated DNA assemblies to reduce complexity and optimize compatibility between parts and methods. It features a wide library of cloning vectors along with a core set of standard SevaBrick primers that allow multipart assembly and exchange of short functional genetic elements (promoters, RBSs) with minimal cloning and design effort. As proof of concept, we constructed, among others, multiple sfGFP expression vectors under the control of eight RBSs, eight promoters and four origins of replication as well as an inducible four-gene operon expressing the biosynthetic genes for the black pigment proviolacein. To demonstrate the interoperability of the SEVA 3.1 vectors, all constructs were characterized in both Pseudomonas putida and Escherichia coli. In summary, the SEVA 3.1 platform optimizes compatibility and modularity of inserts and backbones with a cost- and time-friendly DNA assembly method, substantially expanding the toolbox for successful synthetic biology applications in Gram-negative bacteria.     

VALVE AND BAND MORPHOLOGY OF SOME FRESHWATER DIATOMS I. FRAGILARIA CAPUCINA VAR. MESOLEPTA1,2

Acid cleaned cells from clonal cultures of Fragilaria capucina var. mesolepta Rabh. were examined with light and scanning electron microscopy. Recently isolated cells are linear-lanceolate in shape with a median constriction. After several transfers over 25 mo, cells exhibit size diminution resulting in small elliptically shaped valves. Adjacent valves are united to one another by interlocking marginal spines. Every valve has an apical pore field at each apex. A single labiate process is present infrequtently, appearing underdeveloped most often in size-reduced cells. The girdle region consists of two cingula, each composed of a series of underlapping bands. Each pleura in the series is a discontinuous ring with a central ligula. A survey of past ultrastructure studies on the freshwater Fragilariaceae reveals that the occurrence of the apical pore field and labiate process are likely key characteristics for the family. The apical pore field of Diatoma, Asterionella and Tabellaria is positioned on the valve face, whereas the apical pore field of F. capucina var. mesolepta is located on the valve mantle, the girdle region of F. capucina var. mesolepta is basically similar to that of Gomphonema parvulum (Kütz.) Grun.     

Effect of chemical fertilizers on the transport ofEscherichia coli,Pseudomonas aeruginosa andSalmonella infantis through sand columns

Five commercial fertilizers, Amfos, ammonium sulfate, Kamex, Kieserit and NPK affected the transport ofEscherichia coli, Pseudomonas aeruginosa andSalmonella infantis in sand columns. The percentage of cells transported through sand without fertilizers during a 2-h period was species-dependent (0.56 forS. infantis, 3.1 forE. coli and 12.4 forP. aeruginosa). The cell transport was enhanced by Kamex for all strains tested, whereas Amfos was found to decrease the transport ofE. coli andS. infantis cells. A mathematical model revealed a relationship between the transport of cells and the pH of the sand columns with fertilizers. Columns in which the pH was decreased by the fertilizers exhibited a higher retention of cells. This points to the existence of physico-chemical surface interactions between cells and sand particles.     

Land-use influence on stream water quality and diatom communities in Victoria, Australia: a response to secondary salinization

Diatom communities were analyzed in 39 streams located in drainages with varied land-use practices throughout Victoria, Australia. Thirteen water quality parameters were also measured in each stream. Most streams had low HCO₃ ^1- concentrations (low buffering capacity) with >90% of the waters dominated by Na¹⁺ and Cl^1-. Phosphate concentrations ranged from 0.003 to 2.0 mg/L. Diatom communities (245 taxa) were strongly correlated with land-use practices, i.e. historic clear cutting, and secondary salinization. Streams influenced by heavy irrigation practices and dryland farming had reduced species diversity and richness compared to systems with low to moderate land use. A nonmetric multidimensional ordination of diatom communities in the 39 streams was conducted. An ANOSIM on the ordination showed that diatom communities in upland watersheds with native forest canopies and low salinization, lowland streams in watersheds with cleared forest canopies, moderate agricultural utilization and salinization, and lowland streams in areas with high irrigation and salinization were all significantly different (p<0.001) from one another. Community ordination techniques showed that both specific conductance (salinity) and phosphorus interacted to determine stream diatom community structure in drainages with high secondary salinization. Drainages with low to moderate agricultural activity and low nutrients, but with a wide range of salinities showed strong associations with the diatom taxa Amphora coffeaeformis, Cymbella pusilla and Entomoneis paludosa, whereas, streams in regions with heavy agricultural practices and high phosphorus had Bacillaria paradoxa, Nitzschia hungarica, N. frustulum and Aulacoseira granulata as numerically important diatoms. In contrast, Rhizosolenia eriensis, Frustulia rhomboides, Eunotia pectinatus and Tabellaria flocculosa were strongly associated with upland streams with fast current, relatively low O-PO₄ ^3- concentrations, low pH, low salinity, and low temperature. In general, the diatom communities in saline streams (3 mS) were similar to those previously reported in saline lakes in Victoria.     

Diatoms and water quality in lowland streams in the province of northern Brabant (The Netherlands)

Summary The diatoms of two Dutch lowland streams were studied. The stream Beerze is heavily polluted by the effluent of a sewage treatment plant, causing a change in the pH from less than 4 to more than 6. The acidobiontic diatomEunotia exigua is replaced by more alkaline and eutraphentic species such asGomphonema parvulum, Cyclotelia meneghiniana andFragilaria capucina. The Simpson diversity index rises from 0.2 in the upper course to 0.9 in the middle course and maintains this level in the lower course.From stream Rosep samples of 1919–1930 and recent ones were studied. This stream is polluted now by agriculture. In the earlier samples oligo-mesotraphentic species dominated (Eunotia spp.,Melosira distans). In 1976 the species of organically polluted waters were most abundant. The oligo-mesotraphentic species were hardly recovered.In spite of the severe pollution the number of rare species in both streams is still high, compared with that in stagnant waters. Only in mesotrophic moorland pools and mesotrophic quivering bogs, which are situated in trophic gradients just like both streams, a comparable number of rare species may be found.     

The taxonomy of some Swartzieae (Leguminosae, subfam. Papilionoideae) from southeastern brazil

Three new species of Swartzieae are described and illustrated:Swartzia alternifoliolata, S. capixabensis, andZollernia cowanii. Swartzia apetala var.blanchetii and var.subcordata are considered to be synonyms ofS. apetala var.apetala, andS. grazielana a synonym ofS. macrostachya var.macrostachya. Keys to southeastern Brazil members ofSwartzia andZollernia are provided.     

Moss diatom communities from Ile de la Possession (Crozet,Subantarctica) and their relationship with moisture

More than 190 taxa, belonging to 33 genera, were observed on mosses collected on Ile de la Possession, Crozet Archipelago, Antarctica. Six assemblages could be identified. Habitat type and moisture content of the samples appeared to be the major factors in separating the communities. It was clear that diatom communities growing on mosses found in rivers and brooks are different from assemblages on rocks and in stagnant pools. The Diadesmis contenta assemblage was bound to dry mosses growing on rocks whereas the Eunotia paludosa var. paludosa community preferred acid stagnant pools, situated in the larger valleys. The other four assemblages are typical for circumneutral waterbodies, with the Fragilaria maillardii and the Fragilaria vaucheriae-Fragilaria germainii assemblages found in running water and the Fragilaria pinnata var. pinnata and the Achnanthes confusa-Achnanthes aueri assemblages in more stagnant water. Weighted averaging and calibration were used to develop a statistical transfer function to infer the moisture content of moss samples from the diatom assemblages. Accepted: 29 March 1999     

Zur Morphologie und Entwicklungsgeschichte vonEunotia-Arten (Bacillariophyceae)

After allogamous pairingEunotia tenella produces in each partner cell one gamete containing the two chromatophores of the mother cell and one abortive protoplast without chromatophores. This distribution results from a differential cytokinesis which exhibits the same constant orientation in regard to the epi- resp. hypotheka as in other species ofEunotia. Moreover inEu. tenella andEu. spec. the significant right hand—left hand dissymmetry during the growth of the daughter chromatophores in vegetative cytokinesis is the same as in other species. Both phenomena are significant for the genus and unique. In connection with the diminution of cell size in vegetative divisions the bending of the valvae increases to a certain degree.

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Zur Morphologie und Entwicklungsgeschichte vonEunotia-Arten (Bacillariophyceae)

     

Soil salinity and pH in Japanese mangrove forests and growth of cultivated mangrove plants in different soil conditions

Soil conditions of mangrove forests in southern Japan were found to correlate largely with zonal distributions of the species.Kandelia candel grew in soils with low salinity and low pH,Avicennia marina, Rhizophora stylosa andSonneratia alba in soils with high salinity and high pH, andBruguiera gymnorrhiza in soil with a wide range of pH but limited range of salinity.Lumnitzera racemosa colonized soil with a wide range of pH and medium salinity. Seedlings ofKandelia candel, Bruguiera gymnorrhiza andRhizophora stylosa were planted in soils with differing salinity and pH. Optimum seedling growth ofKandelia, Bruguiera andRhizophora occurred when plants were cultivated in soils similar to those of their natural habitats, suggesting that growth of mangrove species and their zonal distributions were regulated by salinity and soil pH.     

Effect of the nitrogen source on the biosynthesis, composition, and structure of the exopolysaccharides ofAureobasidium pullulans (de Bary) Arnaud

The effect of the nitrogen source and the C/N ratio of the growth medium on the biosynthesis, composition, and structure of the exopolysaccharides (EPSs) ofAureobasidium pullulans (de Bary) Arnaud var.aubasidani Yurlova var. nov. andA. pullulans var.pullulans was studied.A. pullulans var.pullulans andA. pullulans var.aubasidani strains synthesized the maximum amounts of EPSs in the presence of, respectively, a reduced nitrogen source ((NH₄)₂SO₄) and an oxidized nitrogen source (NaNO₃) in the medium. The data presented confirm the validity of using the chemical composition and structure of the major cetavlon-precipitated fraction ofA. pullulans EPSs for the characterization of intraspecies taxa.