bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pleuston and neuston: On the categories of organisms in the uppermost pelagial
Authors: Banse Karl 
Published: February 2007

AbstractThe 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

AbstractThe 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

AbstractIn 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

AbstractFrom 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

AbstractBy 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

AbstractMorphological 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

AbstractThe 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

AbstractThis 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

AbstractIn 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

AbstractThe 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

AbstractSolenofilomorphids 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

AbstractSpectrophotometric 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

AbstractThe 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

AbstractThe 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

AbstractDark 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

AbstractA 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

AbstractThree 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractAn 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

AbstractThe 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

AbstractThere 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

AbstractPeriphytic 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.
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

AbstractThe 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.