bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of Arsenite by Lake Sediments
Authors: Huang Pan M. , Liaw Wen K. 
Published: February 2007

AbstractThe sediments in Blackstrap Lake, a prairie lake, contain over 90% of the non‐clay fractions and its pH is near neutrality. Calcium and Mg carbonates, sesquioxidic components and their complexes with silica are present in a series of particle size fractions. The major clay minerals of the sediments are mica, montmorillonite, chlorite, vermiculite, kaolinite, and quartz.Organic matter of the lake sediments is relatively less important in the adsorption of arsenite. Calcium and Mg carbonates, micas, vermiculite, montmorillonite, kaolinite and chlorite are the active components but not the dominant components of the lake sediments in adsorbing arsenite. The porous sesquioxides and silico‐sesquioxidic complexes present in a series of particle size fractions (clay, silt and sand). are the primary components in adsorbing arsenite. The retention of arsenite by these active components present in sediments would suppress the level of arsenite in fresh water and may thus restrain its movement to the food chain.
Seasonal Changes of Bacterioplankton in a Reservoir Related to Algae. I. Numbers and Biomass
Authors: Straškrabová Vêra , Komárková Jaroslava 
Published: February 2007

AbstractA reservoir for drinking water supply was studied at 10 day intervals for one season. Changes in bacterial microscopic counts and chlorophyll and algal biomass showed a similar pattern. Bacterial peaks usually lagged slightly behind the algal maxima. Average volumes of bacterial cells, corrected for shrinkage, were mostly lower than 0.2 μm3. The average concentration of bacterial C in water was estimated to be 18 μg μg 1 −1 (from a volume biomass of 0.09 mm3 per litre). Several years' fluctuations in bacterial numbers were compared with hydrological data and phyto‐ and zooplankton changes.
Caracteristiques du microphytobenthos d'un lac volcanique meromictique (Lac Pavin, France). I. Biomasse chlorophyllienne et déterminisme du cycle annuel
Authors: Romagoux Jean‐Claude 
Published: February 2007

AbstractCharacterization of the Microphytobenthos in a Volcanic Meromictic Lake (Lake Pavin, France). I. Chorophyll Biomass and Determination of the Annual CycleThe sediments in Lake Pavin are almost exclusively biogen. The fine fraction (≤ 40 μm). comprises 99% of these sediments, making them appear as very fine and fluid silt. Up to 85% of the microphytobenthos is composed of epipelic Bacillariophyceae. The benthos at the different depths studied (10 m, 20 m, 30 m, 40 m, 50 m, and 60 m). are colonized by characteristic populations of diatoms. Analyses of the sediments revealed high concentrations of pigments ( ≥ 1 mg/g dried sediment). Such high concentrations usually result from phytoplankton sedimentation. The deepest area of the lake, as expected, contains the highest concentation of accumulated pigment, while shallower locations are richer in active pigments.
The Availability of Condensed Phosphates for the Algal Strain Scenedesmus obtusiusculus Chodat, with Special Regard to Conditions Characteristic in Lake Balaton
Authors: Dobolyi Elemér , Ördög Vince 
Published: February 2007

AbstractThe limiting factor in the water of Lake Balaton was calculated by means of Verduin's equation. If only the orthophosphate‐phosphorus concentration is inserted into the equation, phosphorus is the primary limiting factor. If, however, total phosphorus is considered, the factor intensity of nitrogen will be the least, i. e. nitrogen will be the primary limiting‐factor of plant growth. According to measurements during 1976, average values for the total dissolved phosphorus and orthophosphate‐phosphorus content of Balaton Lake water were 15,66 mg/m3 and 7.66 mg/m3, respectively. Experiments with the algal strain Scenedesmus obtusiusculus Chod. (Chlorophyceae, Chlorococcales). were designed to test the availability of the condensed phosphorus form for the algae. The experiments were performed partly with synthetic polyphosphates, partly, with polyphosphates isolated from Balaton Lake water. The results showed, contrary to our expectations, that phosphates present in the condensed form (irrespective of their structure and degree of condensation). were not utilized by the algae under sterile conditions, i. e. in the absence of bacterial activity. In the light of the above it is recommended to consider only orthophosphate‐phosphorus when calculating the limiting factor.
Effect of Nutrient Inflow on the Bacterial Flora in the River Sakuragawa, Japan
Authors: Seki H. , Takahara Y. 
Published: February 2007

AbstractThe relationship between nutrient level and microorganisms in the waters of the River Sakuragawa, Japan, was studied from 1976 to 1977. Statistical analyses show that the organic nutrients for the bacteria were mainly autochthonous, and that the water system of the River Sakuragawa was never polluted enough to fall into a condition that could be classified as dystrophic.
Sur la taxonomie et l'éthologie de quelques Orbioninés (Isopoda Epicaridea).
Authors: Bourdon Roland 
Published: February 2007

AbstractLa détermination des Orbioninés de Madagascar (Bourdon, 1979). nous a amené à examiner les types de certaines autres espèces ainsi que des spécimens de provenance variée. Nous présenterons ici les observations morphologiques ou faunistiques nouvelles effectuées sur ce matériel. Sur le plan de la systématique, cet article comprend la description de Parapenaeonella lamellata n. sp. et d'Epipenaeon ingens latifrons n. ssp. et, conséquence d'une meilleure connaissance de la variabilité intra‐spécifique dans la sous‐famille, la mise en synonymie d'Orbione halipori var. libera, O. natalensis, Epipenaeon nobilii et E. grande.
The Effect of Natural and Artificial Shade on the Macrophytes of Lowland Streams and the Use of Shade as a Management Technique
Authors: Dawson F. H. , Kern‐Hansen U. 
Published: February 2007

AbstractThe reduction of the biomass of three main problem species of submerged aquatic macrophytes was proportional to the light at the stream surface both under artificially shaded sections of stream and in naturally shaded areas when compared to the biomass in adjacent open and unshaded sections of stream. The effect of marginal vegetation in varying the shading effect given to streams of differing width and orientation are described. It is recommended that light should be reduced to about half that presently available in the open, by shading from marginal vegetation but it is warned that too much shade is detrimental to the fish populations of the stream and leads to accentuated local accumulations of leaves. The long term effects are considered but it is expected that partial shading will increase the diversity of submerged plant species. It is suggested that the practice of stream realignment is discontinued and that the natural tendency of streams to create their own meandering channels is allowed but within some defined and generally acceptable framework.
Relations between Phytoplankton and Light Climate in two Swedish Forest Lakes
Authors: Ramberg Lars 
Published: February 2007

AbstractThe succession, biomass and production of phytoplankton was studied during 7 years in two Swedish forest lakes in relation to nutrients, temperature and light climate. The succession of species and taxonomic groups can be described by their different demands concerning temperature and light climate while the total biomass is correlated to light climate and total phosphorus concentration. Differences in production between the two lakes can be explained by different taxonomic groups having different efficiencies.
Development of the Periphytic Community on Artificial Substrates in Fish Ponds
Authors: Markošová Ružena 
Published: February 2007

AbstractThe development of the periphytic algae and macrofauna was examined in two fish ponds. 43 genera of algae (mainly diatoms) were found on the substrates, and the maximum of algae was reached on the 10th day. The periphytic macrofauna consisted of 37 taxonomical groups (mainly Chironomidae). Larvae of Cricotopus intersectus were the most abundant species. Since the 2nd day of exposure, the number of Cricotopus larvae strongly increased by immigration of 2nd instars until the maximum was reached on the 15th day. No further significant oscillations were found in either the algal or animal component until the 75th day of exposure.The field observations and laboratory experiments confirmed that:

The distribution of frequencies of Cricotopus larvae found on 200 cm2 surfaces could be approximated by the normal distribution.
The density of the algal periphyton is controlled by abiotic factors, not by grazing by chironomid larvae.
The Cricotopus larvae of the 2nd instar colonize the substrate only after the algal film has been formed. Later instars are sedentary and do not colonize new substrate (except under stress conditions).
Food and predation do not seem to be the factors controlling the Cricotopus population density. The main factor is considered to be the territorial behaviour of the larvae.
The Freshwater Zooplankton of Sri Lanka, with a Discussion of Tropical Freshwater Zooplankton Composition
Authors: Fernando C. H. 
Published: February 2007

AbstractBased on the study of over 500 zooplankton samples collected in Sri Lanka (Ceylon) during 1965–1974, the species composition from different habitats is analysed. The zooplankton assemblage is typically tropical with relatively few species of Cladocera and Copepoda. The Rotifera include a large number of species of the genus Brachionus. The limnetic zooplankton resembles the pond zooplankton closely in that all the eurytopic species found in the different types of habitats, including ponds, also occur in the limnetic zooplankton. The large Cladocera belonging to the genus Daphnia are very rare. In general, large zooplankters are absent. The size composition of the zooplankton has a smaller range than in temperate regions. This is due to the absence of large‐sized zooplankton species.The reasons for the differences in species variety and size composition between zooplankton of temperate and tropical regions is perhaps due to a number of factors. These include the effects of high and uniform temperatures, food availability and predation by fish and invertebrates.
The Rotifera of Hummock‐Hollow Formations in a Poor (Mesotrophic) Fen in Newfoundland
Authors: Bateman Lois E. , Davis Charles C. 
Published: February 2007

AbstractRotifers encountered from a poor (mesotrophic) fen, Avalon Peninsula of Newfoundland, are listed. Sixty‐four species and varieties, including 25 Bdelloidea and 39 Monogononta, were recorded. All but 4 of the reported species and varieties are new records for the Province of Newfoundland, while 27 are new records for Canada; of these, 13 are new for North America.A seasonal quantitative study of rotifer communities in the hummock‐hollow formations on the fen was carried out from August 1973 to October 1974. An average of 354 rotifers/cm2 (17 species) was found per formation. Monogononta almost totally disappeared during winter, while the Bdelloidea decreased somewhat in numbers. The tops of hummocks contained mainly bdelloid species. The number of monogononts increased both in species and individuals on the slopes of hummocks and was greatest in the hollows, although the total number of rotifers was less in these areas than in the hummock tops.Some physical and biological factors affecting the rotifer communities were examined. Rotifers in these sites are not subjected to dessication. Predation was not an important factor.A quantitative sampling method was devised for procuring relatively accurate samples from living Sphagnum, and for extracting rotifers from these samples.
Acidification of a Small Watershed in Southern Norway and Some Characteristics of Acidic Aquatic Environments
Authors: Nilssen Jens Petter 
Published: February 2007

AbstractContinuous monitoring of a small watershed in southern Norway shows that pH has decreased significantly by almost half a unit (from 5.9 to 5.4), conductivity increased from 23 to 29 μS/cm within the period from 1965–1975. Changes are also detected in sediment analyses where Daphnia and Chaoborus are only found deeper than 3–4 cm. Forest clear‐cutting activities have probably accelerated the acidification processes of the already highly vulnerable freshwater localities. The acidic lakes show a solute content below 0.4 meq/1, and the bicarbonate buffer system may no longer work efficiently. Spring thaw and autumn rain episodes are accompanied by strong alternations in the chemical environment of the lakes; by considerable drop in pH and increasing conductivity and sulphate content. With increasing acidification the planktonic community changes from a fish predation governed system (brown trout and Eurasian perch as dominant species) to an invertebrate predation governed one with dominant predators Heterocope and pelagic corixids. Pelagic zooplankton are primarily composed of littoral species: Bosmina longispina, Diaphanosoma brachyurum, Eudiaptomus gracilis and Heterocope saliens. The littoral plant and invertebrate communities are described and discussed.
Seasonal Distribution of Phytoplankton in Yellowknife Bay, Great Slave Lake
Authors: Moore James W. 
Published: February 2007

AbstractThe factors influencing the seasonal distribution of phytoplankton were determined between July 1975 and December 1977 in Yellowknife Bay, Great Slave Lake. The initiation of the spring bloom occurred during April of each year in response to changing light conditions and despite the 0 °C water temperatures. Although the plankton showed some fluctuations in density (100–400 mg/m3) during the summer, there was no vernal decrease in the size of the populations. The end of the growing season was characterized by a sharp drop in numbers near the end of October. Multiple regression analysis indicated that changes in the standing crop of the plankton during the summer were primarily related to temperature (r = 0.60) and the concentrations of NO3–N (r=–0.74) and SiO2 (r=–0.82). Changing light conditions probably had little effect on the population during the growing season.Chlamydomonas lapponica was dominant during April of each year. While the growth of this species caused a reduction in the concentrations of total phosphorus and NO3–N, the level of SiO2 remained constant and consequently diatoms (Asterionella formosa, Stephanodiscus astraea, Diatoma tenue var. elongatum and Melosira islandica) waxed rapidly during May. By the first of June, nutrient concentrations were low, thereby permitting the development of Dinobryon bavaricum and Dinobryon cylindricum. The extremely rapid decrease in the densities of common species during the fall was probably due to the rapid decline in temperature and light levels and the formation of ice on the bay.
On the Mechanism Reducing the Phosphate Concentration in the Water of Lake Balaton
Authors: Dobolyi Elemér , Herodek Sándor 
Published: February 2007

AbstractThe aim of the investigations was to identify the main process controlling the rather low phosphate concentration in the water of Lake Balaton. Three processes were taken into consideration: a) phosphate uptake by algae, b) coprecipitation with biogenic lime, and c) adsorption on suspended sediment particles. A plexiglass box open at the bottom was placed in the shallow water with its sides extending into the sediment. The water in the box was stirred. When phosphate alone was added to the water in the box, its concentration decreased very rapidly. On the other hand, if NaOCl was also added in order to kill algae and bacteria, the phosphate concentration remained constant. This proves the priority of life processes in phosphate removal. In the next experiment phosphate and EDTA‐Na2 were added simultaneously to the water in the box. The complexing agent prevented biogenic lime formation but did not influence the rapid phosphorus removal. This fact indicates that the main process involved in phosphate control is direct uptake by algae. The same conclusion was obtained in laboratory experiments where labelled phosphate was added to the bottles containing Lake Balaton water. It was demonstrated by the photo‐oxidation technique that the phosphate removed from the water was incorporated into the organic particulate matter.
The Species and Size Composition of Tropical Freshwater Zooplankton with Special Reference to the Oriental Region (South East Asia)
Authors: Fernando C. H. 
Published: February 2007

AbstractA contrast between temperate and tropical Cladocera, Copepoda and Rotifera zooplankton fauna shows a markedly different size composition and species diversity. There are fewer species, and these are generally smaller in the tropics than in either the North or South Temperate Zones. Larger species of the generaDaphniaandSimocephalusare relatively rare in the tropics, while members ofEurycerusandSayciaare absent. Members of the families Holopedidae, Leptodoridae and Polyphemidae increase in abundance toward the temperate regions. Two small cyclopoid copepods are common in tropical zooplankton, while many of the common larger species of other regions are absent or very rare. The chief rotifer components areKeratella tropicaand species ofBrachionus.
Automated Pattern Recognition of Phytoplankton – Procedure and Results
Authors: Schlimpert Olaf , Uhlmann Dietrich , Schüller Martina , Höhne Erhard 
Published: February 2007

AbstractPictures of phytoplankton samples were analyzed as raster images by means of a television camera and a Robotron 4200 computer. A feature vector described the objects irrespective of their angle. Each of the five genera involved were identifiable by a characteristic point cluster in a p‐dimensional feature space. A learning method was used during development of the classification structure, and the quality of identification was increased incrementally to the greatest possible degree.Asterionella formosa was identified in all cases without error despite the relatively coarse scanning grid. Errors in the identification of Fragilaria crotonensis can be reduced by improving the resolution (over 100 picture elements per colony).
Contribution to the Study on Bottom Sediment in Lake Balaton. I. Determination of Phosphorus Minerals in the Sediment
Authors: Dobolyi Elemér , Bidló Gábor 
Published: February 2007

AbstractThe aim of the investigation was to determine the phosphorus containing minerals present in Lake Balaton sediment. Chemical, electron microscope and X‐ray diffraction analysis succeeded in identifyinghydroxylapatite.No proof was found for the presence of other phosphorus minerals.
Salinity Tolerance in Some Selected Aquatic Oligochaetes
Authors: Chapman Peter M. , Brinkhurst Ralph O. 
Published: February 2007

AbstractSalt tolerance of the freshwater tubificid Limnodrilus hoffmeisteri varied from an LD 50 of 10 ppt to 10.5 ppt for mature and immature worms without sediment, 9.4 to 10.5 in sand, and 14.3 for immatures acclimated to 5 ppt. Ilyodrilus templetoni was similarly intolerant to higher salinities. The estuarine Tubificoides gabriellae tolerated salt water, but was susceptible to freshwater, with LD 50's of 2 and 3.5 when acclimated to 5 and 10 ppt sea water. It survived immersion in freshwater for 3 hours. The estuarine naidids Paranais litoralis and frici experienced mortalities at both high and low salinities but showed a wide tolerance range. The coastal tubificid Monopylephorus irroratus showed almost complete tolerance to the salinity range employed. The findings reflected field distributions especially when interstitial salinities were measured, but worms did not occupy the full range of habitats possible in terms of salinity alone.
Notobaetis: A New Genus of Baetidae (Ephemeroptera) from South America
Authors: Morihara D. K. , Edmunds George F. 
Published: February 2007

AbstractA new genus and species, Notobaetis penai, n. gen., n. sp., of Baetidae (Ephemeroptera), is described based upon reared specimens collected from the Cordoba Province of Argentina. This new genus appears to be phenetically intermediate between Baetis Leach and Centroptilum Eaton while possessing a unique combination of characters and one autapomorphic character.
The Non‐swimming Chydorid Cladocera of Wet Forests, with Descriptions of a New Genus and Two New Species
Authors: Frey David G. 
Published: February 2007

AbstractIncluded among the diversified aquatic fauna occurring in the water associated with bryophytic coverings of cloud forests and rain forests and with the bottom litter of such forests are two closely related species of chydorid Cladocera – Bryospilus repens gen. et sp. nov. known from Puerto Rico, Venezuela, and New Zealand, and Bryospilus bifidus gen. et sp. nov. known only from New Zealand. Beyond the certainty that these species belong in the subfamily Aloninae because of the nature of their mandible articulation, the location of the minor headpores in a far lateral position, and the general pattern of setation on the trunk limbs, little more can be said. In several respects, most strikingly the lack of a compound eye and certain peculiarities of the mandible articulation, Bryospilus resembles Monospilus more closely than any other chydorid, although this may have resulted from convergence. The species are quite unique in their reduction of setation on the antennae and trunk limb I. The animals cannot swim. Instead they crawl about slowly but effectively in the wet bryophytes and forest litter. They have been collected from as high as 3–5 m above the forest floor, presumably having got there by their own efforts. This habitat is suspected to be comparable in its continuity over time to the ancient lakes of the World and hence can be expected to harbor other “endemic” species as well.
The Phytoplankton Biomass and Species Composition at Two Stations in Western Lake Erie, 1975/76
Authors: Gladish D. W. , Munawar M. 
Published: February 2007

AbstractIntegrated phytoplankton samples from two stations in the northern waters of western Lake Erie were analyzed by the Utermöhl technique for the period from June, 1975 to September, 1976, with weekly sampling in the summer of 1975. No consistent differences were observed between the two stations. Two annual peaks were found: the first was a vernal pulse (1.4 to 4.8 g/m3) comprised primarily of diatoms (86.0–95.7% of total biomass; principal species were Tabellaria fenestrata (Lyngb.) Kg., Stephanodiscus hantzschii Grun., and Fragilaria capucina Desm.); the second peak (3.1 to 9.9 g/m3) was in late summer – early fall. This latter peak consisted of initially diatoms (Coscinodiscus rothii Ehr. Grun. and Melosira granulata (Ehr.) Ralfs being the chief components), later dominated by bluegreens (Aphanizomenon flos‐aquae (L.) Ralfs and Chroococcus minutus (Keutz.) Naegeli), and finally diatoms (Coscinodiscus rothii, Stephanodiscus spp., Fragilaria crotonensis (Edw.) Kitton, and Melosira granulata). The importance of phytoflagellates (25.5 to 93.4% of total biomass), especially Gymnodinium sp., Cryptomonas erosa Ehrb., and Cryptomonas erosa v. reflexa Marsson., in June – early July samples and the overwhelming dominance of diatoms during the remainder of the year are stressed. No patterns in biomass and composition could be observed in vertical phytoplankton profiles. The present study provides an important connecting link between past and future studies performed with the standard Utermöhl technique.