bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field and Laboratory Studies on Nile Phytoplankton in Egypt. I. Some Physical and Chemical Characteristics
Authors: Ahmed Ahmed M. , Haikal Medhat M. , Mohammed Ahmed A. , Zidan Mohammed A. 
Published: February 2007

AbstractMonthly variations of some physical and chemical characteristics of Nile waters at Assiut (375 km south from Cairo, Egypt) during the period from September 1980 to September 1982 were followed and discussed. As expected, the maximum temperature was recorded in summer and the minimum in winter. The pH values of Nile waters were recorded to be in the vicinity of 8.0. The highest oxygen concentrations were recorded in the summer months, mainly due to the relatively high photosynthetic activity. The total soluble salts and the total alkalinity exhibited almost identical trends. Nitrate, phosphate, silicate and chloride concentrations showed no major regular trends. The cation abundances by weight were as follows: Ca2+ > Na+ > Mg2+ > K+.
Vertical Distribution of Tintinnopsis lacustris (ENTZ) and Tintinnidium fluviatile STEIN (Ciliata) in Lake Kozjak (Plitvice Lakes), Yugoslavia
Authors: Primc Biserka 
Published: February 2007

AbstractThe seasonal changes in the vertical distribution of Tintinnopsis lacustris and Tintinnidium fluviatile was studied in the Karst Lake Kozjak, one of the group of Plitvice lakes. The question asked was to what extent does the development of these two species‐populations follow the seasonal fluctuations and spatial distributions of the planktonic community or the seasonal changes in environmental conditions.
Effect of Non‐removal of the Macrophytic Biomass on the Characteristics of Water and Plant Community in Lake Naini Tal, U.P., India
Authors: Purohit Rekha , Singh S. P. , Upreti Neeraj 
Published: February 2007

AbstractIn the most productive macrophytes stand lying within the littoral zone of Lake Naini Tal (a Kumaun Himalayan Lake, located 1937 m above sea level) the macrophytic biomass was removed at the time of peak biomass one year, but not during the next. The effect of non‐removal of the macrophytes was apparent in the physical and chemical parameters of the water, viz: thermal stratification, pH, dissolved oxygen, calcium and nitrogen content. The removal of macrophytes increased the plant diversity. Seasonal patterns of ash, calcium and nitrogen content in plant tissues were different for the two years of study.
Structure of Periphytic Communities in Cooling Pond of Nuclear Power Plant
Authors: Protasov Alexander A. , Afanasyev Sergey A. 
Published: February 2007

AbstractPeriphyton was studied in the cooling pond of a nuclear power plant in the Ukraine. Fourteen periphytic communities called by the dominants were distinguished on the basis of an analysis of visually detected homogeneity distribution and with reference to results obtained from treatment of samples. Relationships among communities were determined by a method similar to taxonomic analysis according to E. S. SMIRNOV. The periphytic communities were shown to be integrated in two “large” communities gravitating towards the thermogradient poles. Temperature was the important factor that determined the macrostructure of periphyton in the cooling pond.
Antarctic Stream Ecosystems: Variability in Environmental Properties and Algal Community Structure
Authors: Howard‐Williams Clive , Vincent Connie L. , Broady Paul A. , Vincent Warwick F. 
Published: February 2007

AbstractThe variability in physical, chemical and biological properties was examined for a number of glacier melt streams in south Victoria Land, Antarctica. Streams flowed for between one and two months. Stream water temperatures (range = 0–11°C) varied over short (hr) time scales whilst discharges varied considerably between streams (range 0.001–15 m3s−1) and over diel cycles. Solar radiation and air temperature were major determinants of stream discharge. Variability in discharge was reflected in variability in nutrient chemistry and sediment load. Nitrogen and phosphorus varied considerably between streams; the meltwaters early in summer contained 10–20 times higher levels of dissolved N and P than later in the season. Within stream nutrient levels were modified by dense algal growths and penguin rookeries. Epilithic algal communities were made up predominantly of cyanophyceae which formed mats and crusts. Longitudinal and horizontal variability of species in the communities in selected streams is described. Analyses of algal cover and biomass (chlorophyll a) show that substrate type and flow rates are of greater importance than nutrients in influencing algal abundance and biomass. In some streams biomass values of over 20 μg Ch. a cm−2 were recorded, much of which remains viable but inactive over the antarctic winter.
Investigations of the Benthos of Mangrove Coastal Lagoons in Southern Cuba
Authors: Lalana‐Rueda Rogelio , Gosselck Fritz 
Published: February 2007

AbstractBenthic studies were undertaken in two mangrove‐lagoons on the south coast of Cuba. Both lagoons are approximately 30–50 cm deep and the tidal range is 15–20 cm. There is little influx of fresh water, and the lagoons are normally euhaline. Most of the lagoon bottom is not colonized by plants, although filamentous algae (Cladophora and Enteromorpha spp.) and Thalassia testudium grow in a few places. Meiobenthic organisms account for 92% of the invertebrates in the benthic zone of the lagoon. The five most common taxa (Nematoda, Copepoda, Tanaidacea, Oligochaeta, Polychaeta) account for 88–94% of the total number of individuals in Tolete Lagoon and in Basto Lagoon the five most common taxa (Nematoda, Copepoda, Ostracoda, Amphipoda, Polychaeta) account for 97–98%. Biomasses were 26.6 g/m2 in Tolete and 20.2 g/m2 in Basto Lagoon. The dominant taxon on the roots of Rhizophora mangle is Crustacea (Balanus eburneus, B. recurvus and Corophium insidiosum), accounting for over 60% of the total number of individuals. They are followed by molluscs (Crassostrea rhizophora) and the polychaetes (serpulids).
A Phytoplankton Bloom in Shallow Divor Reservoir (Portugal)—The Importance of Internal Nutrient Loading
Authors: Cabeçadas Graça , Brogueira Maria J. , Windolf Jörgen 
Published: February 2007

AbstractThe development of a heavy phytoplankton bloom (chl. a = 360 mg/m3), which occurred in the summer 1983 in a shallow reservoir, Divor, is described. The study shows that remobilization of phosphate from the sediment was initiating the phytoplankton bloom. This was confirmed not only by calculations of the change in iron‐phosphate pool, but also supported by sorption experiments carried out with the sediment. It is discussed that turbidity of the water due to suspended matter caused the reduction in standing stock of phytoplankton to approx. 50 mg chl. a/m3 in late summer.
Distribution of Macrophytes in Relation to Environmental Factors in the Ter River, N. E. Spain
Authors: Peñuelas Josep , Sabater Francesc 
Published: February 2007

AbstractMost of the tested water quality factors increase downstream coinciding with changes in the aquatic vegetation, from typical species of fast‐flowing oligotrophic waters to those of slower‐flowing eutrophic waters. Several statistic analyses were carried out to relate physical and chemical parameters with plant distribution. Five vegetation types are found in a longitudinal distribution along the river system. They are dominated by bryophytes in the initial parts before the reservoirs and by higher plants in the final parts after the reservoirs.
Stratigraphy of Cladocera (Crustacea) and Chironomidae (Insecta: Diptera) in Three Sediment Cores from the Central Baltic Sea as Related to Paleo‐salinity
Authors: Hofmann Wolfgang 
Published: February 2007

AbstractIn three sediment cores from the Central Baltic Sea (Bornholm Basin, Gdansk Bay) corresponding horizons with maximum abundance of remains of a limnetic fauna (Cladocera, Chironomidae) were found. These associations indicate the existence of an oligotrophic freshwater lake. However, this horizon does not coincide with the Ancylus stage but is located in sediment layers from the very end of that period, or from the Mastogloia stage, which was a transitional brackish water phase.
Effects of Sewage Dumping on Macrobenthic Invertebrates in the Jordan Gulf of Aqaba, Red Sea
Authors: Ismail Naim S. , Awad Jamal 
Published: February 2007

AbstractThere are two sewage outfalls along the Jordanian coastline in the Gulf of Aqaba. During 1982 and 1983 a total of 328 core samples (0.01 m2 to a depth of 15 cm) were collected from the two outfalls, two control stations which resemble the outfalls in depth and sediment texture, and from two stations 100 m on both sides of each outfall. Faunal analysis revealed that the total number of individuals, number of species, species richness, and faunal similarities of macrobenthic invertebrates were lower at the sewage outfall near the phosphate loading port than the control station during both collections. At the 100 m stations, the numbers of individuals were generally higher than the sewage and control stations. The number of species, however, was highest at the control station and lowest at the sewage outfall.At the other sewage outfall, where the sewage effluent is discharged sporadically, no measurable effects on macrobenthic invertebrates were found.
Computer Aided Interactive Classification and Mapping of Aquatic Areas
Authors: Forsgren Per‐Ola , Wallsten Maud 
Published: February 2007

AbstractClassification and mapping of aquatic vegetation is an important task in limnology. In this paper we will present a new computer aided and interactive method for this purpose. It is similar to older techniques in that the classification relies on the judgement of the human eye. The precision is increased by using a linear diode array scanner and the evaluation times are reduced by introducing computer vision techniques. Combining these in an interactive environment gives the operator a powerful tool for the classification. The results from a mapping of aerial infrared colour photographs will be presented.
Factors Affecting the Benthic Community Structure of a Discontinuous Stream in Guadelupe Mountains National Park, Texas
Authors: Meyerhoff Richard D. , Lind Owen T. 
Published: February 2007

AbstractMcKittrick Creek, a discontinuous mountain‐desert stream in Guadelupe Mountains National Park, Texas, was sampled at discrete locations (pools) to test for differences in biomass, density, species diversity, equitability, and species richness in the benthic macroinvertebrate community. Significant differences occurred among pools for these biotic characteristics of the benthic community along the downstream gradient. Pools connected by flow were more similar to each other than pools separated by dry reaches. Variation in the quantity of coarse detritus and periphyton best explained differences among pools.
Field Studies Concerning the Fecundity of Daphnia galeata, its Causes and Consequences
Authors: Horn Wolfgang , Horn Heidemarie 
Published: February 2007

AbstractField studies on a Daphnia galeata population in the mesotrophic man‐made lake Saidenbach show that the fecundity of the animals depends on individual size, water temperature and the food supply (absolute quantity, specific food supply, food quality). These different factors are subsumed in the ingestion rate (rate of individual food intake per unit time), which is of an integrative character. The fecundity plotted versus ingestion rate yields a graph with the shape of a saturation curve. Attention is drawn to the consequences in terms of variation in population size.
Photosynthesis of Natural Populations of Aphanizomenon flos‐aquae: Some Ecological Implications
Authors: Pechar Libor 
Published: February 2007

AbstractThe photosynthetic characteristics of different natural populations of Aphanizomenon flos‐aquae RALFS ex BORN. et FLAH. were measured in laboratory. Two types of A. flos‐aquae, partly var. klebahnii (small needle‐like colonies, 0.1–0.3 mm long on the average, growing at transparency reduced by high density of nanoplankton to about 0.5 m) and partly var. flos‐aquae (colonies flake‐like up to 20 mm long, which grow when transparency is about 1.5 m or higher) were investigated. The photosynthesis‐irradiance (P–I) curves of var. klebahnii were characterized by a high value of the initial slope and photoinhibition at relatively low light intensities (250–400 μE. m−2. s−1). In var. flos‐aquae the P–I curves had a lower initial slope and no photo‐inhibition was observed in the range of irradiance to 450 μE. m−2. s−1. The effect of different sizes of colonies on photosynthesis and possible impact of strong light (induced by Daphnia feeding activity) to promoting the large‐flakes Aphanizomenon in the presence of large Daphnia are discussed.
Biology of Latia neritoides Gray 1850 (Gastropoda, Pulmonata, Basommatophora): the Only Light‐producing Freshwater Snail in the World
Authors: Meyer‐Rochow V. B. , Moore S. 
Published: February 2007

AbstractThis report on the freshwater pulmonate basommatophoran Latia neritoides of the North Island of New Zealand is based on field and laboratory studies. It deals with aspects of the habitat, describes biological adaptations of organs and organ systems in Latia, reviews the chemical basis of bioluminescence in this species, discusses the possible roles of light production in Latia, and addresses zoogeographic and phylogenetic questions.
Polychaetous Annelids from the Gulf of Nicoya, Costa Rica
Authors: Maurer Don , Vargas Jose , Dean Harlan 
Published: February 2007

AbstractPolychaetous annelids from a soft bottom community (1–46 m) were sampled from the Gulf of Nicoya, Costa Rica. A total of 125 species was identified, 120 from a faunistic study throughout the gulf and 78 species from a time study at four stations. The number of species from the Gulf was not as high as in some temperate areas. Temporal differences were slight compared to station differences. Twenty dominant species indicated three descriptive patterns: 1) Species with a marked seasonal peak and stable densities thereafter; 2) Species with a moderate seasonal peak and stable densities thereafter; and 3) Species with no discernible seasonal peak. Although 10 polychaete feeding guilds were identified, species from six feeding guilds were the dominant groups. The effect of the rainy season on polychaete opportunism and feeding guilds was discussed.
A Three Years' Study of Life Cycle, Population Dynamics and Production of Asellus aquaticus L. in a Macrophyte Rich Stream
Authors: Iversen Torben Moth , Thorup Jens 
Published: February 2007

AbstractPopulations of A. aquaticus were sampled quantitatively in 1979–82 at two localities in the river Suså which has a slope of <1 m km−1 and large variations in macrophyte biomass, discharge and stream velocity. The latter two differed significantly between years. A. aquaticus had (1)−2 life cycles per year and summer and winter cohort production intervals of 85 and 290 days. Populations of A. aquaticus varied between 0 and 28,000 ind. m−2 with an exponential increase in the spring and an exponential decrease in the autumn‐winter. The A. aquaticus rate of decrease varied between 0.62 and 5.61 % d−1 and increased with increasing rate of elimination of the macrophyte biomass Differences between the two localities were due to differences in physical heterogeneity. Production varied between 2.8 and 9.1 g DW m−2 yr−1 and between 12.9 and 55 g DW m−2 yr−1 at the two localities and P/B ratios were 7.4–9.9 yr−1. Physical limitations are thought to be most important for the populations of A. aquaticus in the Suså, and the macrophyte biomass played an important role in modifying the physical environment. Differences between streams and lake populations are discussed.
Meteorological and Hydrographical Features of Vellayani Lake, Kerala, India
Authors: Jayachandran K. V. , Joseph N. I. 
Published: February 2007

AbstractMeteorological, physical and chemical parameters of Vellayani Lake, Kerala, India, have been analysed for twelve months (August 1980 to July 1981), the topography of the lake is described, and correlation coefficients were calculated between meteorological and hydrographical parameters. The results indicate that the lake can be converted into a productive aquafarm by means of slight manuring.
The macrophytes in lake Änketjärn—a lake dominated by Juncus bulbosus L
Authors: Svedäng Maria 
Published: February 2007

AbstractThe distribution of macrophytes and the biomass development during the summer was studied in the slightly acidified Lake Änketjärn in western Sweden. The submerged cyperid Juncus bulbosus, which has been reported to expand in acidifying lakes, covered almost 50% of the lake area. The most dense Juncus vegetation was found at 1.5 m on loose, highly organic sediment. Besides J. bulbosus the vegetation was characterized by Nympheids, Carex rostrata and C. lasiocarpa (approximately equally important in the stands), Equisetum fluviatile and Lobelia dortmanna, species which showed a quite distinct zonation with depth.
Nucléotides adényliques et assimilation photosynthétique du phytoplancton dans deux lacs du Massif Central français
Authors: Amblard Christian 
Published: February 2007

Adenine Nucleotides and Phytoplanktonic Primary Production in Two Lakes in FranceThe adenine nucleotides concentrations and photosynthetic assimilation of phytoplankton were established during two annual sampling seasons for two lakes with different nutrients concentrations (Lakes Pavin and Aydat). Intensive photosynthetic assimilation of phytoplankton led to a limited but real evolution of the pool of adenine nucleotides towards forms less charged with high energy phosphate bond (ADP and AMP). This evolution is seen as a consequence of the ATP hydrolysis in the process of cell biosynthesis.
Die Veränderung populationsdynamischer Parameter bei Gammarus tigrinus Sexton (Crustacea: Amphipoda) als Ausdruck subletaler Effekte durch die Wechselwirkung von Temperatur und cadmiumkontaminiertem Futter
Authors: Hackstein Elisabeth 
Published: February 2007

Changes in the Population Dynamics of Gammarus tigrinus SEXTON (Crustacea: Amphipoda) as Expression of Sublethal Effects by Reciprocal Interactions of Temperature and Cadmium Enriched FoodThe population dynamics of Gammarus tigrinus SEXTON were studied in a flow‐through system under semi‐natural conditions over a period of 9 months. Elevated temperatures and Cadmiumenriched food alter lifespan of generations, growth rate, number of individuals and time to reach maturity, even before elevated Cadmium concentrations can be detected in the animals. Reciprocal interactions of Cadmium intake via food and/or water can be modified by the experimental design, because it depends on the experimental animals, on the Cadmium concentration and on the temperature regime with constant or cyclic conditions.
The Ecology of Baetis muticus and Baetis rhodani (Insecta, Ephemeroptera), with Special Emphasis on Acid Water Backgrounds
Authors: Willoughby L. G. 
Published: February 2007

AbstractThe two mayflies (Insecta, Ephemeroptera) Baetis muticus and Baetis rhodani are absent from the acid water (pH 4.8–5.2) streams of the Upper Duddon drainage basin. Field observations and laboratory experiments were used in an attempt to explain this absence. Baetis muticus could not tolerate acid water; in addition it was deduced that available foods in the Upper Duddon streams would not sustain it there, even if the water could be tolerated. Baetis muticus feeds by browsing on decaying, allochthonous leaves, implying an input of micro‐organisms, especially fungi, to the diet. Well‐decayed, allochthonous leaves do not occur in the acid water, Upper Duddon streams. Baetis rhodani proved to be acid water tolerant, but only if the background waters had high ionic loadings. Since Upper Duddon waters have only low ionic loadings, Baetis rhodani is apparently excluded from them on this account. The evidence was that if the Upper Duddon waters were chemically suitable, then Baetis rhodani could survive in them, because a suitable food, the alga Hormidium subtile is present.
Temporal and Spatial Meiofauna Fluctuations in an Inlet of the South West Baltic (Darss‐Zingst Bodden Chain) with Special Reference to the Harpacticoida (Copepoda, Crustacea)
Authors: Arlt Günter 
Published: February 2007

AbstractDiurnal, seasonal and annual fluctuations of the meiofauna population density were recorded during long term investigations carried out in an inlet of the southwestern coast of the Baltic from 1970 to 1980. Field experiments have shown a diurnal vertical migration of harpacticoids, which leave the sediment at night to colonize the pelagic zone 14 times more densely than during day. Besides the seasonal fluctuations considerable differences were observed between the meiofauna densities in two successive years from samples taken twice in a grid consisting of 98 stations: the abundances of all meiofauna taxa decreased by approximately 50 %. These fluctuations are not only caused by the reproductive activities of the meiofauna under different environmental conditions, but they are to a great extent a result of the active and passive movements of the meiofauna.
Valvata piscinalis O. F. MÜLLER (Mollusca, Prosobranchia) and its Epizoic Diatoms from Lake Trichonis, Greece
Authors: Falniowski A. , Economou‐Amilli A. , Anagnostidis K. 
Published: February 2007

AbstractThe ultrastructure of Valvata piscinalis O. F. MÜLLER, a mollusc collected from Lake Trichonis, Greece, is illustrated by SEM and compared with Polish specimens. The specific features observed are leading to the characterization of the specimens as an ecotype. The epizoic algal growths, ascertained by direct examination or scraped from shells of V. piscinalis, are commented.
Calcium and Magnesium in Dal Lake, a High Altitude Marl Lake in Kashmir Himalayas
Authors: Ishaq Mohammed , Kaul V. 
Published: February 2007

AbstractMonthly sampling of calcium and magnesium in the in‐ and outflows of Dal Lake revealed high concentrations of both during summer. The monthly inputs, outputs and retentions of these alkaline earths were estimated. The lake on an overall basis showed the retention of calcium but not of magnesium. This was suspected to be related and affected by variable flushing rates of water. Most of the calcium and magnesium was present in sediments and only a small fraction in the water and in macrophytes. The calcium balance is discussed in relation to the P‐balance.
Sublittoral Macrobenthic Infaunal Assemblages of Two Nearby Embayments from Central Chile
Authors: Carrasco Franklin D. , Gallardo Victor A. , Medrano Sonia 
Published: February 2007

AbstractThe benthic assemblages in two Central Chile nearby embayments were studied from quantitative samples collected from 15 sites at depths of 8–65 m. The macrobenthic infauna (<0.5 mm) of both bays was greatly dominated by polychaetes. Some 93 taxa were identified, of which 51 were polychaetes. The average macrofaunal abundance for all stations (15,021 ind. m−2) is very close to the values reported for the neighboring areas. Numerical classification and ordination (DCA) of sites resulted in three site‐groups mostly reflecting differences in the bottom sediments: the muddy‐bottom stations of Concepción Bay and the shelf‐associated stations, the sandy‐bottom stations of San Vicente Bay and an heavily polluted station at San Vicente port. Classification of species showed that the muddy‐bottom stations and the sandy‐bottom sites had characteristic species assemblages. The macrofaunal assemblages presented high dominance values, which were due to the high numerical abundances of a few species in the collections.