bluuebunny/crossref_metadata_2025_split huggingface dataset:
Les Diatomées Holocènes du Bassin Inferieur de l'Aouache (Dépression des Danakil, Ethiopie). Leur Signification Paléoécologique
Authors: Gasse Françoise 
Published: February 2007

Holocene Diatoms of Lower Awash Basin (Danakil Depression, Ethiopia). Their Paleoecological MeaningSome residual lakes can be observed in the lower Awash Basin (Danakil Depression, Ethiopia). During the Lower Holocene period, a big lacustrine episode, already known in the South‐Saharian area, has been evidenced here. The deposits are rich in diatoms. Their systematic and quantitative study give valuable information on the ecological and climatic conditions of their sedimentation. During the optimal lacustrine period, the diatoms were the most abundant and the most varied. This period was preceded by several short oscillations of the water level. The shores of the paleolake were marshy, but its central area was deep enough for planktonic flora to prevail. Lacustrine, alkaline waters, rich in nutritive elements of organic origin, were not very saline. However, the salinity reached high enough values to allow the growth of brackish species. The quantitative importance of tropical diatoms shows that a hot climate occured in the Danakil Depression at the beginning of the lacustrine episode. During the lacustrine optimum the temperature was probably lower.
The Effects of Hydrostatic Pressure on Living Aquatic Organisms I. The Problem and General Behavioral Responses
Authors: Menzies Robert J. 
Published: February 2007

AbstractBehavioral responses of marine and aquatic animals are characterized as R1 (a first response of prolonged excitation), T (tetany or paralysis), I (inactivity and relaxation) and death as measured by the LD50. R1, T, and I are reversible responses and temperature dependent with each response occurring at high pressures as temperature increases. The lethal response is also temperature dependent but the tolerance to pressure increases with decreasing temperature. The responses are examined with reference to the ability of animals to successfully cope with the high pressure and low temperature of the abyssal environment.
The Effects of Hydrostatic Pressure on Living Aquatic Organisms IV. Recovery and Pressure Experimentation on Deep‐sea Animals
Authors: Menzies Robert J. , George Robert Y. , Paul Allen Z. 
Published: February 2007

AbstractCapture of living deep‐sea animals is reviewed. The conditions for the successful recovery of living animals from the deep‐sea are elaborated with examples. Control of pressure, temperature, or both, appears to be a prerequisite for the capture of living deep‐sea animals. Deep‐sea animals (archibenthal) show a loss of the R1 response in comparison with their shallow‐water counterparts. Genuine deep‐sea animals have now been recovered in a living state suitable for experimentation from the High Arctic.
The Effects of Hydrostatic Pressure on Living Aquatic Organisms V. Eurybiotic Environmental Capacity as a Factor in High Pressure Tolerance
Authors: Menzies Robert J. , Selvakumaran M. 
Published: February 2007

AbstractStudy on the total spectrum of organisms (72 species) subjected to hydrostatic pressure as of this date allows one to established categories of pressure tolerance (resistance): Extremely high – eurybiotic forms (1000–1200 atm), High – marine littoral, planktonic, freshwater (600–1000 atm), Moderate – marine littoral, planktonic, freshwater (400–600 atm), Low – planktonic, freshwater (100–300 atm), Extremely low – planktonic, freshwater (0–100 atm). The average pressure tolerance of marine littoral species is higher than that of planktonic species but not significantly different from freshwater species. Eurybiotic species which are not marine seem to show the highest pressure tolerance.
Seltene „‐Algen”︁ und Nannoplankter aus Teichen des Waldviertels (Nieder‐Österreich)
Authors: Wawrik Friederike 
Published: February 2007

Rare „μ‐Algae”︁ and Nannoplankton from Ponds of the Waldviertel (Nieder‐Österreich)The following rare μ‐ and nannoalgae, found in small ponds in the Waldviertel in Lower Austria are discussed: Microcystis ferruginea, Pedinomonas minutissima, Chlamydomonas dactylococcioides, Sphaerellopsis lefevrei, Scenedesmus denticulatus var. fenestratus, Siderocelis kolkwitzii, Nephrochlamys allanthoidea, Kirchneriella irregularis, Coccomyxa minor, Catena viridis.
The Distribution of Isopoda in the Delaware Bay Region
Authors: Watling Les , Lindsay John , Smith Ron , Maurer Don 
Published: February 2007

AbstractThe distributions of 24 marine and estuarine isopods have been reviewed. Lironeca ovalis, Aegathoa medialis, Olencira praegustator, and Probopyrus pandalicola were the only parasitic species found. Of the 20 free‐living isopods, Asellus communis and Chiridotea almyra were the only fresh to brackish water species, and Chiridotea arenicola, C. stenops, Cirolana impressa, C. polita and Edotea montosa were the true marine species. The salinity range of Cyathura burbancki was extended and the range of Chiridotea stenops was extended northward while the ranges of Chiridotea nigrescens and C. arenicola were extended southward. The contribution of isopod distributions to the concept of a shallow water Transatlantic zoogeographic province is discussed.
Ein mathematisches Modell der Massenentwicklung planktischer Diatomeen
Authors: Kozerski Hans‐Peter 
Published: February 2007

A Mathematical Model of Blooms of Plankton DiatomsBlooms of plankton diatoms are of great importance for the management of drinking water reservoirs in the southern regions of the German Democratic Republic. A mathematical model has been developed by the author in order to find out optimal management alternatives. The model consists of coupled differential equations.The first step is a very simple model which is compared with a mass development of Asterionella formosa in the Saidenbach reservoir in the Erzgebirge. The dynamic properties of the improved model are examined with respect to the influence of various ecological parameters and that of initial values. It could be shown that loss rate and initial biomass of phytoplankton exert the greatest influence of bloom dynamics. In the last step, the results of the model are compared with a bloom ef Asterionella in laboratory cultures and with recent data obtained from the reservoir. A qualitative comparison between model behaviour and observations in the lake gives information about the validity range of the model parameters and provides ideas for further development. The applicability to water quality management of the model is considered.
The Limnology of a New Zealand Reservoir, with Particular Reference to the Life Histories of the Copepods Boeckella propinqua SARS and Mesocylops leuckarti CLAUS
Authors: Green John D. 
Published: February 2007

AbstractThe Auxiliary Nihotupu Reservoir, near Auckland, New Zealand, was studied during 1967‐68. The reservoir was emptied for a short time during the study. Changes in physico‐chemical factors, phytoplankton and zooplankton were followed throughout the year. Thermal stratification was evident over the summer and the partitioning of oxygen and pH at this time is discussed. An acid heterograde pH curve is reported. From an analysis of oxygen deficits it is suggested that the reservoir may be oligotrophic.An analysis of egg production, length distributions and changes in developmental stages was used in interpreting the life cycle of Boeckella propinqua. Development times from egg to adult, and approximate survival rates are briefly considered. Mesocyclops leuckarti is also discussed and the annual cycles of both copepods are compared with those in other New Zealand lakes.
The Seasonal Succession of Species in a Rice Paddy in Vientiane, Laos
Authors: Heckman Charles W. 
Published: February 2007

AbstractA study was made of the community of organisms present in a rice paddy in Vientiane, Laos. The paddy was visited regularly for eighteen months, and the pattern of seasonal succession was studied. The major biological characteristics were noted including relative abundance of the 205 species observed. A few species were consistantly common whenever there was sufficient water in the paddy, but most had well defined seasonal periods during which they were abundant and actively propagating. In time the number of individuals of these dominant species declined and other species replaced them. During the part of the year that the field was flooded, four distinct aggregations of species succeeded each other. Thus, in the biological year of the rice paddy, two primary phases, dry and wet, were easily discernible, and within the wet phase, four periods could be defined by the successive aggregations of species. The species identified were similar to those reported to occur in the rice paddies of Northeast Thailand, but biological studies of Laos have been so infrequent that most species are reported for the first time from Laos, hence extending their geographical ranges.
Distribution, Circulation et Evolution des Eléments Nutritifs, en Particulier du Phosphore Minéral, dans l'Etang de Berre. Influence des Eaux Duranciennes.
Authors: Minas Monique 
Published: February 2007

Distribution, Circulation and Evolution of Nutrients, Inorganic Phosphorus Particularly, in Lake Etang de Berre. Influence of River Durance WatersNutrients, phosphorus in particular, were studied at five locations in the brackish lake Etang de Berre's waters in order to examine vertical and horizontal distributions, seasonal and annual evolutions, and circulation.The phosphorus cycle was surveyed taking into account the extensive freshwater input from the river Durance which was recently deviated into the Etang de Berre.Of primary importance is the phenomenon of trapped nutrients in the deepest layer of the lake, corresponding to the occurrence of a pycnocline (halocline). This layer is in a steady state characterized by anoxic conditions and shows denitrification processes.
Ökologische Untersuchungen an Ciliaten in einer Modellselbstreinigungsstrecke
Authors: Greiser Dagmar 
Published: February 2007

Ecological Investigations on the Ciliated Protozoa Associated with the Self‐purification Process under Laboratory ConditionsThe environmental conditions and the associations of ciliates occurring within the process of self‐purification were investigated using a series of 7 laboratory ecosystems connected mutually by means of tubes. The first ecosystem of the series received periodically a certain amount of artificial sewage which required about a fortnight to pass through the whole system. The individual ecosystems, therefore, reflect different stages of increasing self‐purification.
Reproduction in Laboratory Stocks of Pleuroxus (Chydoridae, Cladocera) Under the Influence of Photoperiod and Light Intensity
Authors: Kuo‐Cheng Shan R. 
Published: February 2007

AbstractThe effects of photoperiod and light intensity on the reproduction of laboratory populations of three species in Pleuroxus from different geographic origins were determined statistically. There were highly significant differences in the numbers of gamogenetic individuals produced between the populations at different photoperiods but not at different light intensities. More males than ephippial females appeared at long‐day photoperiods. Pleuroxus denticulatus stocks showed greater variation of gamogenetic response to photoperiod and geographic origin suggesting that local populations have evolved different reproductive patterns to meet the major environmental stresses of the region.
Das Sediment des Kummerower Sees. Untersuchungen des Chemismus und der Diatomeenflora
Authors: Kalbe Lothar , Werner Heinz 
Published: February 2007

The Sediment of Lake Kummerow. Investigations on the Chemism and the Diatom FloraThe paper deals with the distribution of chemical parameters and of diatoms in the deposits of the eutrophic Lake Kummerow (GDR), produced during about the last 3500 years. The sediment consists of a calcareous gyttja with a very low content of sand and clay. The results indicate a relatively constant trophic state of the lake in former times and an increased production within the last five centuries. Stephanodiscus astraea and its variety minutula is by far the most constant diatom species; in the uppermost parts of the sediment small sized planctonic taxa are increasing, in the main Stephanodiscus hantzschii var. pusillus, Melosira granulata var. angustissima, Asterionella formosa and Synedra acus var. angustissima and var. radians.
An Analysis of the Nutrient Contribution by Phytoplankton Primary Production to the Food Web of a Small Lake
Authors: Waite Don T. , Duthie H. C. 
Published: February 2007

AbstractPhytoplankton primary production was measured for 148 days, from May 31 to October 25, 1971, in Sunfish Lake, Ontario, using the 14C light and dark bottle technique. The purpose of the experiment was not only to measure the rate of production but also to give some indication of the fates of the material produced by the algae.The following data were calculated for the sampling season: total gross production 57,770.6 mg C m −2; algal respiration 31.74% of gross production; total net production 39,895.4 mg C m −2; extracellular production 9.2% of total net production. The efficiencies of both gross and net total production were inversely correlated with light intensity. The rate of extracellular production was directly correlated with the rate of total production. The rate of respiration was not significantly correlated with either the rate of gross production or with the algal biomass as calculated from differential cell counts. The weekly rate of phytoplankton turnover was calculated by combining measurements of algal biomass with net particulate production measurements. The turnover rates for the phototrophic zone ranged from plus 6,788.5 mg C m −2 to minus 1,104.4 mg C m −2 The negative figure indicates an increase in algal biomass which can not be accounted for by primary production. The rate of phytoplankton turnover was compared with fluctuations in the standing crop of zooplankton but the correlation was not significant. Gross and net rates of extracellular production were estimated and compared. There was no significant difference between the two measurements and the implications of this are discussed with respect to other work in the field.
Equilibrium and stability in laboratory model of sewage ponds and polluted rivers
Authors: Uhlmann Dietrich , Cramer Franz 
Published: February 2007

AbstractThe persistence under controlled chemical and physical conditions and the ability to respond to defined environmental changes was follow d in extremely simple (homogenous or 2‐phase) ecosystems with continuous or semicontinuous flow. In the homogenous case the Aufwuchs was removed. Primary productivity and community respiration were computed by means of continuous recording of dissolved oxygen. Under constant environmental conditions the systems usually exhibited slow oscillations of the ecosystem parameters around an equilibrium state. The temporal variations of functional criteria such as elimination rate of easily degradable organic substances or daily oxygen amplitude were slight in comparison to the significant random oscillations in individual numbers of the predominating species of phytoplankton and zooplankton. One of the mechanisms responsible for this functional stability may be the inverse relationship between biomass and activity per unit biomass as observed also in the laboratory models. If the sewage pond microecosystems after a shut down in the inflow were operated without any exchange of nutrients and gases they nevertheless maintained a very high level both of autotrophic and heterotrophic metabolism. Step forcing of nutrient (sewage) concentration, dilution rate or day length produced a new equilibrium state within 1 or 2 days, if the functional criteria mentioned above were taken as output signals. Also in the case of pulse forcing such a rapid adaptation was to be observed. This may contribute to the fact, that the turnover rate of the population was in the same range as the renewal rate of the water. The results are discussed with respect to short and long term effects of abatement of pollution from flowing and standing waters.
Seasonal variation of the planktonic population in lake yunoko, as followed by the assay of chlorophyll, protein, RNA and DNA in the total harvested planktonic samples
Authors: Iwamura Tatsuichi , Nagai Hiroko , Yamaguchi Yukuya 
Published: February 2007

AbstractSeasonal variation of the biomass of plankton in Lake Yunoko, a eutrophic lake in Japan at an altitude of 1478 in, was followed by measuring simultaneously the quantities of chlorophyll, protein, RNA and DNA in water samples harvested from different depths at a definite site in different seasons of a year. The contents of the four cellular constituents and the sum of them in a given water column showed characteristic seasonal changes during the year. Various ratios derived from the four contents were grouped into two distinct types; one is the winter‐spring type and the other the summer‐autumn type. It was found that the sum of the four contents and the ratio of the protein‐content to the RNA‐content were quantitatively related to the chlorophyll‐content of the water. Based on the assumption that a certain water sample contained only photosynthetic plankton, analyses were made to estimate the proportions of photosynthetic and non‐photosynthetic plankton to the total planktonic mass, the growth rates of these plankton, and the net productivity of the lake.
Nutrient loading to cook bay of lake Simcoe from the Holland river watershed
Authors: Nicholls Kenneth H. , Maccrimmon Hugh R. 
Published: February 2007

AbstractDuring a limnological investigation of the Holland River, Holland Marsh and Cook Bay of Lake Simcoe (Ontario, Canada), an evaluation was made of the magnitude and significance of nutrient contributions to the West Branch of the Holland River and to Cook Bay from mixed agricultural‐woodland, mixed agricultural‐urban, intensively cultivated marsh and uncultivated marsh subcatchment areas within the watershed. The importance of the “net input” concept is discussed in an attempt to assess the relative importance of contributions of nutrients from areas of different land use practices on the watershed. Recognizing the relatively high contribution of total phosphorus (2.1 kg P/ha yr) in drainage water pumped from the intensively cultivated marsh, changes in the management of the cultivated marsh are suggested which would conceivably reduce the phosphorus loss in drainage waters from these areas.
The distribution of Branchiostoma senegalense (Acrania, Branchiostomidae) in the off‐shore shelf region off North West Africa
Authors: Gosselck Fritz 
Published: February 2007

AbstractDuring investigations on the macrobenthos between 17° N and 26° N on the North West African continental shelf, abundant stocks of Branchiostoma were found off Spanish Sahara (23° N‐25° N), on the d'Arguin Bank (21° N‐20° N) and off Gambia (12° N‐13° N). The lancelets were identified as Branchiostoma senegalense (WEBB, 1955) by means of statistical analyses. The lancelet populations occur at dephts down to about 40 m. Deeper regions are probably avoided because of the excessively high detritus content. Favourable environmental factors such as temperature, composition of the sediment and food supply permit high lancelet abundancies. Up to 9000 animals'm2 were found in the population off Spanish Sahara. Rough calculations showed that the lancelet population comprises about 6 × 1012 individuals with a biomass of 1.5 million tons. The potential natality amounts to about 45 × 1015 larvae a year.
Littoral Benthos of the Northern Baltic Sea. I. Introduction
Authors: Luther Hans , Hällfors Guy , Lappalainen Annikki , Kangas Pentti 
Published: February 2007

AbstractThe background and the aims of the Finnish IBP‐PM programme are discussed. The research programme is outlined, with special reference to the study of the littoral communities. The research areas (Tvärminne, 59°50′N, 23°15′N and Krunnit, 65°25′N, 24°50′E) are briefly described. The sampling programme, the sampling methods, the treatment of the samples and the gross structure of the collected material are presented.
Littoral Benthos of the Northern Baltic Sea II. Interrelationships of wet, dry and ash‐free dry weights of macrofauna in the Tvärminne Area
Authors: Lappalainen Annikki , Kangas Pentti 
Published: February 2007

AbstractWeight determinations have been made by standard methods, for the species of the common, littoral macrofauna of the Tvärminne area, S Finland. Equations are provided, for species or higher taxa, for the prediction of dry weight from wet weight, and of ash‐free dry weight from dry weight, applying the ratio model, the linear model and the curvilinear model. Factors affecting the weight estimates, including preservation in formalin, and some factors affecting the interrelationships of the weights have been discussed.
Observations on particulate and dissolved organic matter in coral reef areas
Authors: Marshall Nelson , Durbin Ann G. , Gerber Ray , Telek Gregory 
Published: February 2007

AbstractData are presented on the particulate and dissolved organic carbon at Eniwetok Atoll in the Pacific and of particulate organic carbon at South Caicos in the Caribbean. Some data from other locales are included for comparison. Proportionate increases are greater for the particulate matter released from off reefs than for the dissolved; in fact, the net flux of dissolved matter is sometimes negative.Particulate matter, in this case of the size and kinds retained on micro‐filters, is dominated by fragments and amorphous material of mixed origins. Phytoplankton is sparse in such environments.
Seston composition in the point pelee area of lake erie
Authors: Leach Joseph H. 
Published: February 2007

AbstractApproximately one‐third of organic seston in western Lake Erie was estimated to be living algae; the remainder was mainly detritus. The amount of detrital carbon was least in summer and maximal in autumn. Allochthonous organic matter, particularly municipal and industrial wastes, and resuspended sediments were considered to be major sources of detritus.
Planktonic ecosystems. The effects of dystrophic conditions on structure and function in the gulf of fos
Authors: Blanc FrançOis , Leveau Michel , Bonin Marie‐claude 
Published: February 2007

AbstractIn the areas studied, an unusual structure and dynamic behavior was exhibited by the plankton ecosystems, due for the most part to industrial and natural effluents from the Rhǒne and Durance. The ecosystem was kept at a low state of maturity, which is characterized by frequent periods of intense multiplication by small species with high metabolic rates, such as the diatom, Skeletonema costatum, and the dinoflagellates, Exuviaella and Prorocentrum. Brackish water seems congenial to that type of proliferation.The turnover rate of these populations decreases as they become older and cell size increases. A lack of competition by species of the same genus is a characteristic of the photo‐autotrophic organisms in these environments. Secondary production follows the same cycle as the primary production by the dinoflagellate population. Zooplankton species of the genus Acartia have periods of intensive development in these areas.
Einwanderung mariner Nematoden in das Süßwasser. Untersuchungen in Kolumbien im Vergleich mit außertropischen Regionen
Authors: Riemann Franz 
Published: February 2007

AbstractThe available information on the distribution of nematodes does not demonstrate a significant latitudinal difference in the numbers of marine species colonizing freshwaters. This result contrasts with the often‐stated comparative richness of marine elements in tropical freshwaters, as established by macrofauna observations. Because of this discrepancy the arguments explaining the abundance of marine elements in tropical freshwaters are reconsidered in physiological, statistical and historical perspective.