bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Study 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

The 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 Diatoms

Blooms 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

The 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

A 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 Waters

Nutrients, 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 Conditions

The 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

The 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 Flora

The 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

Phytoplankton 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

The 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

Seasonal 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

During 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

During 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

The 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

Weight 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

Data 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

Approximately 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

In 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

The 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.
Pleuston and neuston: On the categories of organisms in the uppermost pelagial
Authors: Banse Karl
Published: February 2007

The development of the connotations attached to the terms pleuston, neuston, and some of their derivatives is outlined. In the marine literature, the term hyponeuston has presently two principal. quite different meanings: organisms attached from below to the surface film and largely supported by it, and organisms frequenting the upper decimeter of the sea. To reduce the ensuing confusion in the marine realm and to maintain uniformity of aquatic terminology, the term endopleuston is proposed as a replacement for the second, recently acquired meaning of hyponeuston. Another new term, exopleuston, refers to positively buoyant organisms with dry upper surfaces which, however, live principally underwater, in the habitat of the endopleuston. The pleustal is recognized as the habitat of these organisms. It may be useful to regard it as a category. of equal rank the epipelagial or bathypelagial.
Analyses of temporal variation in the structure of a shallow‐water benthic community in nova scotia
Authors: Levings Coli N. D.
Published: February 2007

The dominance structure of a shallow water (17 m), soft‐bottom community at St. Margaret's Bay, Nova Scotia was studied using multivariate statistical methods over the period January 1970 to January 1971. Seventy‐four species were encountered in the samples, and the majority were crustaceans and polychaetes. Ordination was the best method, compared to classification and measures of species diversity, for determining the changes in dominance from the mass of complex data. An ostracod (Normanicythere leioderma), two polychaetes (Micronephytis minuta and Prionospio steenstrupi), and an amphipod (Photis reinhardi) were identified as the species that determined change in the assemblages resulting from the multivariate analyses. The changes in these species' population structure were related to seasonal fluctuations in temperature.
Characterization of the coral reefs off veracruz/mexico characterización de los arrecifes de corales de Veracruz/Mexico
Authors: H. H. Kühlmann Dietrich
Published: February 2007

In May 1965 and June 1966 an ecological study of the Arrecife Blanquilla, Arrecife Pajaros, Bajo Verde and Anegada de Adentro coral reefs off Veracruz, Mexico was made using aqualungs. The present work summarizes and discusses the existing knowledge about these reefs which is still incomplete. Similarly structured reef portions and similar features found in a number of reefs in ecologically comparable locations led the author to conclude that the reefs as a whole are similar to each other. In their position on the shelf, their round‐oval shape, their elevated ridges, their shallow lagoon‐type centres and their tendency to form islands they are basically comparable to the platform reefs of the Australian Great Barrier Reef. The coral associations have been produced by the environmental factors prevailing in the three recognizable habitats, the surf zone, the shallow body of calm water, and the steep slopes with moderate water movement. The coral fauna was found to be poorer than that of other reef areas in the West Indies.
Untersuchungen über Individuendichte, Biomasse und kalorische Äquivalente des Makrobenthos eines Waldbaches
Authors: Caspers Norbert
Published: February 2007

From 1972 to 1974 the invertebrates of a woodland‐brooklet of the “Naturpark Kottenforst‐Ville” (Rhineland) were investigated concerning abundance and standing crop at selected sampling stations of the “epirhithron”. In the shaded brooklet the allochthonous autumn‐shed leaves proved to be the most important food for the aquatic invertebrates. Carbon‐14 radioisotope tags were used to get data on the primary productivity of the periphyton community, which is less important for the energy balance of the macrobenthic organisms. The most frequent macroconsumers are Gammarus fossarum KOCH, Leptophlebia marginata L. and some caddis larvae which feed directly on detritus and decomposing leaves.
Prognose der Phytoplanktonentwicklung in geplanten Talsperren durch Kombination von wachstumskinetischen Modellvorstellungen und Analogiebetrachtungen zu bestehenden Talsperren
Authors: Benndorf Jürgen , Zesch Martina , Wiesner Eva‐Maria
Published: February 2007

By deriving the most significant physical characteristics (mixing depth. temperature of the mixed layer, length of the winter stagnation period) from existing reservoirs in connection with a simple mathematical model it was possible to predict the phytoplankton growth and biomass in designed reservoirs. The method described is applied to a designed reservoir. The reliability of the prediction method is tested by comparing the calculated results for the existing Saidenbach reservoir with the data measured in this water body by HÖHNE (1970) and HOFMANN (1972).
Monograph of the solenofilomorphidae (Turbellaria: Acoela)
Authors: Crezée Michael
Published: February 2007

Morphological studies of eleven new species in the family permitted reconstruction of progressive evolutionary lines, and this strongly implies progressive evolutionary lines for other acoela.

Solenofilomorpha funilis n. sp., Myopea crassula n. g. n. sp., M. latafaucium n. sp., Fusantrum rhammiphorum n. g. n. sp. and Endocincta punctata n. g. n. sp. are described from the coast of South Carolina, U.S.A., and S. guaymensis n. sp. is described from the Gulf of California. Five additional unnamed species from the U. S. Pacific Coast, Sweden and Tunisia are briefly described.

Two species groupings were based on correlation between two different arrangements of pharynx muscles and trio arrangements of antrum muscles and further correlations with lesser characters. The membership of the two groupings in a single family make it clear that evolution proceeded by addition of structures to a less complex common ancestor. Functional and behavioral considerations support the evolutionary path drawn from morphology. Distinctive statocyst structure, ciliary interconnections and sperm morphology shared by acoels show them to have a common ancestry, but clearly different pharynges and male structures cannot be consistent with evolution by reductions. A common ancestor of low complexity has probably given rise to several partly parallel evolutionary lines which together form the structurally diverse Acoela. The history of acoel systematics is also briefly summarized.
The algal flora in the Thermal Baths of Montegrotto Terme (Padua). Its distribution over one‐year period
Authors: Andreoli Carlo , Rascio N.
Published: February 2007

The results of a one year period study on the algal flora in the muds and in the spring water of Montegrotto Terme (Padua) are reported. Temperature and pH do not seem to have any direct influence on phytoplankton population, but their variation must depend from other not yet identified factors.
The Ecological and Morphological Characteristics of Microorganisms in Lesnaya Lamba (Karelia)
Authors: Dubinina Galina A. , Kuznetsov Sergei I.
Published: February 2007

This paper contains the results obtained in the investigations of morphology, ultrastructure and vertical distribution of microorganisms in a stratified lake, Lesnaya Lamba, Karelia. The culture of Ochrobium tectum (PERF.) was produced for the first time, and the bacterial nature of this organism was shown by investigating its ultrathin structure. The presence of gaseous vacuoles was also revealed, which explains the migrational ability of ferritized cells. Several new microorganisms were detected, including the filamentous photosynthetic green bacterium Chloronema giganteum (nov. gen. nov. sp.), a consortium of a new symbiotic form of green bacteria named Chloroplana vacuolata, formerly unknown tiny purple bacteria and blue‐green algae Gloeocapsa, oxidizing iron. It was revealed that more than half of the bacterio‐plankton in the bottom layer possess gaseous vacuoles; they are represented by various morphological forms. The vertical distribution of iron bacteria — Siderocapsa (Arthrobacter), Ochrobium, Siderococcus and other species is regulated according to ecological niches by the concentration of oxygen and iron, and, in phototrophs, by the amount of light and the presence of a certain type of bacteriochlorophyll. All in all, the distribution of nine species of phototrophic bacteria in the lake is described.
Relationships Between Sediment Chemistry and Postglacial Production Rates in a Small Canadian Lake
Authors: Adams R. W. , Duthie H. C.
Published: February 2007

In a chemical investigation of the sediments of a small meromictic lake in southwestern Ontario, Canada, the hypolimnion had evidently become increasingly reductive over most of the postglacial as the lake gradually filled in. The ratio of phosphorus to organic matter tended to fall, suggesting that an increasing proportion of precipitated phosphorus had become mobile and re‐available to the lake's ecosystem. Productivity, as inferred from fossil pigment analysis, tended to increase over the postglacial, and there is no evidence for a prolonged period of trophic equilibrium. Maximum production rates were correlated with efficient phosphorus diagenesis. The lake evidently became meromictic around 900 BP (before present) and this was associated with a sulphide producing monimolimnion and decreased productivity. Cultural practices in the watershed around 140 BP increased inorganic sedimentation and further reduced productivity.
Physical and Chemical Conditions in Long Pond, St. John's, Newfoundland: A Pond Receiving Both Rural and Urban Runoff
Authors: Andrews C. W. , O'Connell M. F.
Published: February 2007

The physico‐chemical environment was studied from June 1971 to May 1973 at five stations in Long Pond, St. John's, Newfoundland. This pond receives both rural and urban runoff and is characterized by a high flushing rate. Of the parameters studied, concentrations of total suspended matter, biochemical oxygen demand (BOD), total CO2, and free CO2 were significantly greater in a small pool prior to the main body of the pond near the entry of Learys Brook. Current speed is noticeably reduced at this point. No significant differences were found between stations with respect to pH, dissolved O2, total dissolved solids (TDS), total hardness, Ca hardness, Mg hardness, alkalinity, ammonium‐N, nitrite‐N, nitrate‐N, orthophosphate and polyphosphate. Water quality in Long Pond is compared with unpolluted lakes and streams in the area; nutrient levels are indicative of eutrophic conditions.
Solenofilomorphidae (Acoela), Major Component of a New Turbellarian Association in the Sulfide System
Authors: Crezée M.
Published: February 2007

Solenofilomorphids are of world‐wide distribution and live in association with the sulfide system, the anoxic and micro‐oxic layers of marine sediments. The 58 species of turbellarians on an intertidal sand flat in North Carolina, U.S.A., formed three species assemblages. The solenofilomorphids are a major part of a sulfide system assemblage which is centered in the mid‐tide region and which is intermediate in density and diversity between the two separate species assemblages in the surface layers of the upper and lower tide regions. Oxygen avoidance does not explain restriction of species to the sulfide system, and food preferences for and behavioral responses to specific bacterial species are suggested as proximal causes for observed distributions.
Pigment Diversity in Freshwater Phytoplankton. I. A Comparison of Spectrophotometric and Paper Chromatographic Methods
Authors: Hallegraeff Gustaaf M.
Published: February 2007

Spectrophotometric and paper chromatographic analyses of the pigments in the phytoplankton were made from early spring till the end of summer in two small Dutch freshwater lakes. It was found that pigment diversity cannot be adequately estimated by MARGALEF'S pigment ratio nor by polychromatic spectrophotometric methods. The pigments detected with the paper chromatographic method were: chlorophyll‐a, chlorophyll‐b, chlorophyll‐c, phaeophytin‐a (traces), phaeophorbide‐a, Mg‐containing chlorophyll‐derivatives, carotene, lutein, violaxanthin, neoxanthin (traces), fucoxanthin, diadinoxanthin, diatoxanthin (traces), peridinin and keto‐carotenoids (traces). It is suggested to distinguish between a richness‐component and an evenness‐component of pigment diversity.
Studien zur Typologie von baltischen Seen unterschiedlichen Eutrophierungsgrades. Investigations on the Typology of Baltic Lakes with Different States of Eutrophication
Authors: Ventz D.
Published: February 2007

The recycling of phosphorus is considered as a process of internal eutrophication and related to the hypolimnetic oxygen balance. The rate of change in orthophosphate is compared with the temporal change in oxygen content by means of statistical methods. The slope and the shape of the ΔP/ΔO2‐curves may serve as a basis for lake classification.
The Standing Stock of Diatoms and Dinoflagellates in the Oligotrophic Waters of Southern Aegean Sea
Authors: Ignatiades Lydia
Published: February 2007

The hydrography and seasonal changes in the standing stock of diatoms and dinoflagellates were studied in 9 stations located in Southern Aegean Sea. The logarithms of the measurements of each stock in each station were subjected to analysis of variance with the factors “station” and “season”. The results suggested a uniform distribution of phytoplankton at all stations within every season. On the other hand there was a significant effect of season upon phytoplankton growth. The annual temperature range (14.2 d̀C‐25.6 d̀C) and the phytoplankton cycle (maxima in spring and autumn) provided evidence of the temperate character of this area.
Blooms of Surf‐zone Diatoms Along the Coast of the Olympic Peninsula, Washington. VIII. Effect of Temperature and Oxygen Concentration on Respiration of Chaetoceros armatum in the Natural Environment
Authors: Robertson Scott , Lewin Joyce
Published: February 2007

Dark respiration rates of the surf diatom species, Chaetoceros armatum, were measured in field experiments throughout a year‐round study. Measurements of dissolved oxygen were made by employing the Winkler oxygen technique. Oxygen concentration in the ambient water had a significant positive effect upon respiration rate at all temperatures encountered during the period of study (4.6d̀ up to 13.8 d̀C). Above 8d̀, respiration rate increased with increasing temperature up to about 12.5d̀. Above 12.5d̀, temperature had a detrimental effect. The relationship between the concentration of dissolved oxygen and respiration rate was confirmed experimentally by artificially lowering or raising the oxygen concentration.
Tenuignathia rikerae nov. gen., nov. spec., a New Gnathostomulid from the West Atlantic
Authors: Sterrer Wolfgang
Published: February 2007

A further paper dealing with West Atlantic Gnathostomulida presents the new monotypic genus Tenuignathia. The presence of a full sensorium and a cuticular bursa place the new genus within the order Bursovaginoidea, sub‐order Scleroperalia; the simple jaws and pharynx, the bipartite ciliary pits as well as epithelial characters clearly suggest inclusion in the family Mesognathariidae. Found in Florida, North Carolina and Bermuda so far, Tenuignathia displays an unusually wide range of jaw length even within a narrow geographic range, which will be the subject of a separate study.
Comparative Life Histories of Three Species of Tropisternus in the Laboratory (Coleoptera: Hydrophilidae)
Authors: Hosseinie Shidokht O.
Published: February 2007

Three species of Tropisternus (T. lateralis nimbatus) [SAY], T. collaris [subspecies] [FABRICIUS], and T. blatchleyi modestus [D'ORCHYMONT] have been reared in the laboratory over a period of several years for determination of the genetics of their color patterns and various physiological studies. Methods of rearing and handling are discussed, and the behavior, duration of life history stages, and general biology of adults and immature stages are summarized.
Boring by Macro‐organisms in the Coral Montastrea annularis on Barbados Reefs
Authors: Macgeachy James K. , Stearn Colin W.
Published: February 2007

The fauna boring into Montastrea annularis includes sponges, bivalves, sipunculid and polychaete worms and barnacles. Sponges are most important in hard tissue destruction and account for more than 90% of the total boring in most heads. Bivalves and barnacles are locally important. Sipunculids and sabellids account for less than 4% of the total boring.

The volume removed from coral samples by boring ranged from 3–60% and samples from a deeper bank reef were more highly bored than fringing reef samples. An average of 20% of the volume of bank reef corals, and 5% of the volume of fringing reef corals, was removed by boring.

The distribution of individual borers is not a function of depth. The density and variety of borers and the extent of boring in coral heads is greater in older heads. The ratio of living coral surface to dead encrusted areas on colonies also influences borer density and the extent of boring.
The Effect of Stable Dissolved‐Oxygen Stress on Marine Benthic Invertebrate Community Diversity
Authors: Nichols Jean Ann
Published: February 2007

The Fosa de Cariaco off the coast of Venezuela is an anoxic basin which is subject to small seasonal fluctuations in the depth of the anoxic water. Samples taken in the interface region (between oxic and anoxic waters) contained from 13 to 37 species represented by 117 to 380 individuals. Species‐diversity, based on H′(s), was greater than that previously reported for samples from oxygen minimum regions. It is suggested that the relatively stable low dissolvedoxygen concentrations allow the development of diverse assemblages.
Effet de l'enrichissement continu en nitrates sur les populations de Diatomées isolées à l'aide d'enceintes expérimentales placées dans un étang oligotrophe
Authors: le Cohu René
Published: February 2007

The influence of nitrates (NH4NO3 KNO3 and Ca(NO3)2) on Diatom populations has been studied. These populations were isolated by enclosures with transparent walls, without bottom or lid, placed in an oligotrophic pond. The addition of NH4NO3 generally resulted in a decrease in the number of Diatoms and the disappearance of some species. The addition of KNO3 and Ca(NO3)2 was followed, during some periods, by a very important increase of Achnanthes minutissima, Fragilaria construens and Gomphonema parvulum.
Decomposition of Urea by the Larger Particulate Fraction and the Free Bacteria Fraction in a Pond Water
Authors: Satoh Yasuhiro , Hanya Takahisa
Published: February 2007

An aliquot of a water sample taken from an artificial pond on the campus of the Faculty of Science, Tokyo Metropolitan University, was filtered with Whatman GF/C glass fiber filters. Urea was added to the filtered and unfiltered waters, respectively to a final concentration of around 10 μg‐at‐N/l. These samples were kept in 10 liter glass bottles, which were kept on the surface of the pond with rope. Changes in the concentrations of urea, ammonium, nitrate, nitrite, and the number of bacteria were traced from 15 June through 13 July, 1973.

The urea added to the unfiltered water decreased to about 1 μg‐at‐N/l within first three days. The decrement of the urea seemed to proceed as a first‐order reaction with rate constant of 0.73 day−1. On the other hand, the urea added in the filtered water kept nearly the initial concentration for 18 days. As the number of bacteria in the filtered and unfiltered water were not significantly different, decrease of the urea in the unfiltered water may be ascribable to the participate fraction removed by the filtration. The urea was not decomposed by free bacteria.
Simultaneous Quantitative Comparison of Planktic Crustacea in Two Newfoundland Boreal Lakes
Authors: Davis Charles C.
Published: February 2007

The number, size and reproductive potential of the planktic Crustacea were compared from March to December 1973 in two Newfoundland lakes, namely Hogans Pond and Bauline Long Pond. In the first period of the study the total number of microcrustaceans was greater in the more fertile Hogans Pond, but after October all species in Hogans Pond declined catastrophically. The relative numbers of individual species are detailed, some being more abundant in one lake and some in the other. Body lengths of most copepods were the same or greater in Hogans Pond than in Bauline Long Pond, but the cladoceranDaphnia catawbawas larger in Bauline Long Pond. The number of eggs carried per female was usually the same or greater in Hogans Pond, except forDiaptomus minutusandDaphnia catawbain the spring.
An Evaluation of Phosphorus‐Chlorophyll‐Phytoplankton Relationships for Lakes
Authors: Nicholls K. H. , Dillon P. J.
Published: February 2007

There is considerable variation in published phosphorus‐chlorophyll relationships, some of which can be accounted for by variation in sampling and analytical techniques. As well, there can be significant inherent variability in a single phosphorus‐chlorophyll relationship under even ideal sampling and analytical conditions. A survey of the literature shows that the cellular chlorophyll content of algae ranges over two orders of magnitude (0.1—9.7% of fresh weight). Average daily radiation intensity and nutrient availability (especially N) appear to be the major factors controlling chlorophyll content of algal cells. The relationship between total phosphorus and phytoplankton biomass for a group of Ontario lakes is better defined if summer average cell volume is used instead of average chlorophyll a concentration.
Assessing Changes in Biomass of Riverbed Periphyton
Authors: Liaw Wen K. , Maccrimmon Hugh R.
Published: February 2007

Periphytic biomass in a downriver riffle of the Grand River in Southern Ontario, Canada was measured with concrete‐block glass slide samplers from May to December 1971. Average rate of accumulation of periphyton on glass slides was 266.2 mg/m2/day ash‐free weight, 120.9 mg/m2/day carbon, 20.4 mg/m2/day nitrogen, or 1.11 mg/m2/day chlorophyll a and on concrete blocks was 590.0 mg/m2/day ash‐free weight, 202.9 mg/m2/day carbon, 22.8 mg/m2/day nitrogen, or 2.95 mg/m2/day chlorophyll a. The standing biomass of periphyton on glass slides varied from a maximum of 21.6 g/m2 between May 28 and July 15 to a minimum of 0.7 g/m2 in December with an average of 8.6 g/m2. The biomass on concrete blocks ranged from a high of 132.5 g/m2 in August to a low of 29.9 g/m2 in October with a mean of 66.1 g/m2. The well established periphyton on concrete blocks towards the end of the study period was similar to that from native rocks with respect to biomass, carbon and nitrogen contents, and ratios of biomass to chlorophyll a. This suggests that concrete blocks are a better substrate than glass slides for measuring riverbed periphyton. By comparing biomass of periphyton on slides and on concrete blocks, the average rate of loss of periphyton from concrete blocks was estimated to be 2.9 g/m2/day, representing 63% of the mean total accumulation rate of the periphyton. The magnitude of the estimated total loss and the high standing biomass of the periphyton on concrete blocks manifest the importance of the periphyton as a source of organic matter in the river.
The Saline Lakes of Saskatchewan I. Background and Rationale for Saline Lakes Research
Authors: Hammer U. Theodore
Published: February 2007

The historical background and utilization of southern Saskatchewan is described. The utilization of the saline lakes is discussed and the rationale for studying them is outlined.
Anaérobiose au niveau des sédiments et répartition des bactéries au sein de la colonne d'eau. Anaerobic Conditions at the Mud Level and the Distribution of Bacteria in the Water Column
Authors: Bertrtj Georges
Published: February 2007

The influence of anaerobic conditions on the distribution of bacteria has been studied. At the interface mud — water, bacteria using organic compounds of small molar weights come into sight, showing that the mud releases organic matter into the superficial water column which promotes mixotrophic algae.
Die Zoobenthos‐Gesellschaften des Piburger Baches (Ötztal, Tirol). The Zoobenthos Assemblages of Piburger Bach (Oetztal, Tyrol)
Authors: Kownacka Marta , Margreiter Gerhard
Published: February 2007

Piburger Bach is a short, spring‐fed lake affluent. The macrozoobenthos of this stream has been studied both qualitatively and quantitatively. More than 15,000 specimens of invertebrates, including all developmental stages of insects, were collected; a high proportion of these was identified to the genus or species level. The spatial and temporal distribution of various taxa as well as their quantitative contribution to the total macrobenthos are discussed. Confidence limits of the data are considered.
The Measurement of Groundwater Discharge into a Lake by a Direct Method
Authors: Lock Maurice A. , John Peter H.
Published: February 2007

An apparatus is described which allows groundwater discharge through lake beds to be measured directly. On transects at right angles to‐the shore‐line of Lake Taupo, New Zealand, discharges Mere found to decrease rapidly with distance from the shore. The potential use of this technique in the construction of nutrient budgets for lakes is outlined.
Experiments with Large Enclosures in a Fertile, Shallow, Brackish Lake, Hickling Broad, Norfolk, United Kingdom
Authors: Leah R. T. , Moss Brian , Forrest D. E.
Published: February 2007

Events in the plankton community of a 120 ha, shallow (1.2 m), brackish lake have been studied with the help of two watertight enclosures, each of which isolated about 300 m3 of water and its underlying sediment. Analyses of soluble reactive phosphorus, total phosphorus, ammonia‐N, nitrate‐N, silicate‐Si, chloride, photosynthetic pigments, phytoplankton and zooplankton counts are reported and are related to inputs of nitrogen and phosphorus into the lake from adjoining basins and the catchment, and to the hydrologic regime. The inputs of phosphorus are budgeted and a very large roost of black‐headed gulls appears to provide most of the phosphorus supply. The results are discussed with reference to the eutrophication of the lake and decline of aquatic macrophytes which have occurred in the past ten years.
The Saline Lakes of Saskatchewan III. Chemical Characterization
Authors: Hammer U. T.
Published: February 2007

The salinity of Saskatchewan saline lakes varies up to 342%0. Highly saline lakes are widely distributed. Some reach saturation at high summer temperatures but salt precipitation occurs on cooling. Saline lakes tend to increase in salinity with time but the greatest changes occur in the shallow more saline lakes.

The lakes are dominated by sodium, magnesium and sulphate. The cation sequences are dominated by sodium or magnesium while calcium and potassium are proportionally much smaller. Chloride or bicarbonate‐carbonate are secondary to sulphate among the anions. Ion sequences tend to be characteristic of certain physiographic regions. Lake types were magnesium (sodium) sulphate, sodium sulphate and sodium (magnesium) sulphate in order of abundance of lakes.

Phosphorus and ammonia were high in concentration but nitrate and silica were scarce. The lakes were all alkaline between pH 7.8 and 9.8.

The evolution of closed saline lakes is briefly discussed.