bluuebunny/crossref_metadata_2025_split huggingface dataset:
DIFFERENT CHEMICAL TYPES OF PLOCAMIUM VIOLACEUM (RHODOPHYTA) FROM THE MONTEREY BAY REGION, CALIFORNIA1
Authors: Crews Phillip , Campbell Lisa , Heron Elaine 
Published: August 2007

ABSTRACTDifferences in the halogenated natural products of Plocamium violaceum Farlow can be noted from different sites in the Monterey Bay region, California. Specimens from the northern region produce a set of alicyclic halogenated monoterpenes which are not synthesized by those from the southern region. Instead, the latter elaborates a set of acyclic halogenated monoterpenes not observed from the former. This situation is invariant regardless of life history forms or different seasons. Similarly, the composition of halogenated monoterpene structures from P. cartilagineum (L.) Dixon varies at different locations. From the data presented herein we conclude that at least two chemical types can be identified for P. violaceum based upon differences in their halogenated products. Thus we suggest that the north Monterey form can be designated as chemotype α and the southern one as chemotype β.
DISTRIBUTION OF DIATOMS IN THE PLANKTON OF YAQUINA ESTUARY, OREGON1
Authors: Karentz Deneb , McIntire C. David 
Published: August 2007

ABSTRACTThe distributional patterns of diatoms in the plankton of the Yaqnina Estuary, Oregon, were, investigated and related to selected climatic and hydrographic factors. Distribution was strongly influenced by seasonal patterns of rainfall resulting in the introduction of a large volume of fresh water into the estuary during fall and winter. Plankton assemblages in spring, summer and fall had fewer diatom species and exhibited a more rapid rate of change in species composition than in winter. Winter assemblages were further characterized by many pennate diatoms, apparently dislodged from the benthos during periods of high freshwater discharge and silt loads. A statistical measure of community difference indicated an increase in taxonomic homogeneity among assemblages throughout the estuary with the onset of the rainy season in late fall and a gradual transition to a more heterogeneous system again during late spring. Canonical correlation ordered 20 prominent diatom taxa along the salinity gradient and identified possible relationships among certain taxa and selected environmental variables, namely visible light energy and temperature. Redundancy in the species data given the environmental data was only 40%, emphasizing the difficulty in demonstrating a quantitive relationship between plankton dynamics in the field and concurrent measurements of chemical and physical variables.
EFFECTS OF LIGHT INTENSITY AND TEMPERATURE ONCRYPTOMONAS OVATA(CRYPTOPHYCEAE) GROWTH AND NUTRIENT UPTAKE RATES1
Authors: Cloern James E. 
Published: August 2007

ABSTRACTSpecific growth rate ofCryptomonas ovatavar.palustrisPringsheim was measured in batch culture at 14 light‐temperature combinations. Both the maximum growth rate (μm) and optimum light intensity(Iopt)fit an empirical function that increases exponentially with temperature up to an optimum(Topt),then declines rapidly as temperature exceedsTopt.Incorporation of these functions into Steele's growth equation gives a good estimate of specific growth rate over a wide range of temperature and light intensity. Rates of phosphate, ammonium and nitrate uptake were measured separately at 16 combinations of irradiance and temperature and following a spike addition of all starved cells initially took up nutrient at a rapid rate. This transitory surge was followed by a period of steady, substrate‐saturated uptake that persisted until external nutrient concentration fell. Substrate‐saturated NO3−‐uptake proceeded at very slow rates in the dark and was stimulated by both increased temperature and irradiance; NH4+‐uptake apparently proceeded at a basal rate at 8 and l4 C and was also stimulated by increased temperature and irradiance. Rates of NH4−‐uptake were much higher than NO3−‐uptake at all light‐temperature combinations. Below 20 C, PO4−3‐uptake was more rapid in dark than in light, but was light enhanced at 26 C.
EFFECT OF TEMPERATURE ON LIGHT‐LIMITED GROWTH AND CHEMICAL COMPOSITION OF SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)1
Authors: Yoder James A. 
Published: August 2007

ABSTRACTPhytoplankton growth rate in response to irradiance can be approximated by a hyperbola defined by three coefficients: i) initial slope (α); ii) asymptote (μm); and, iii) X‐axis intercept or compensation irradiance (Ic). To mathematically represent the interaction of temperature and irradiance on growth rate, one must describe the relationship between these constants and temperature. The marine diatom, Skeletonema costatum (Greville) Cleve, was grown in unialgal culture at different levels of irradiance and 2‐3 photoperiods at 0, 5, 10, 16 and 22 C. The value of Ic is ca. 1.0 ly·day−1 or less at all temperatures. The initial slope (div·ly−1) is a “u‐shaped” function of temperature described by the second degree polynomial, α= 0.25–0.02T+0.001T2. Within the range 0–10 C, μm (div·day−1) is an exponential function of temperature described by the equation, μm= 0.48 exp (0.126T). At each temperature and selected levels of irradiance, cell size and cellular content of C, N and chl a were determined. The C:chl a and N:chl a ratios increased with irradiance because of increases in C and decreases in chl a. At lower temperatures (0, 5, 10 C), the rate of increase of both ratios with irradiance was greater than at the higher temperatures (16, 22 C). Cellular content of N was independent of irradiance and temperature, and the C:N ratio ranged from 5 to 8 with a slight tendency to lower values at low irradiance. Cell volume was not influenced by either temperature or irradiance.
MECHANISMS OF RAPID PHOTOSYNTHETIC ADAPTATION IN NATURAL PHYTOPLANKTON COMMUNITIES. I. REDISTRIBUTION OF EXCITATION ENERGY BETWEEN PHOTOSYSTEMS I AND II1
Authors: Vincent Warwick F. 
Published: August 2007

ABSTRACTAn inverse linear relationship between chlorophyll fluorescence yield (R) and light intensity was recorded in the near‐surface waters of six lakes (New Zealand, England) of greatly different trophic status and phytoplankton species composition. This surface depression of R values could be removed by incubation of samples in dim light or darkness and was not observed in situ below a threshold irradiance (146 μEin ·m−2·s−1 for Lake Taupo, New Zealand). The time course of chlorophyll fluorescence depression and recovery in response to light treatment was measured in samples from Lake Windermere (England). Fluorescence exponentially decreased upon exposure to bright light and the response was 100% (5 m samples) or 83% (dim light‐adapted 0 m samples) complete within 2 min. An increase in R values in the dim light occurred after a lag of 60 s and the rate of increase decreased exponentially with time. Full recovery took 15 min or more. Deep (6.5 m) populations from Lake Windermere exhibited large, time‐dependent variations in chlorophyll fluorescence over the first 25 s of exposure to 450 nm light, whereas surface populations did not. These data were interpreted in terms of decreased spillover from PSII to PSI with increasing depth, to a minimum at the threshold light intensity below which cells are in light state 1.
PIGMENTATION AND MORPHOLOGY OF A MARINE GYRODINIUM (DINOPHYCEAE) WITH A MAJOR CAROTENOID DIFFERENT FROM PERIDININ AND FUCOXANTHIN1
Authors: Bjørnland T. , Tangen Karl 
Published: August 2007

ABSTRACTChlorophylls and carotenoids of a small unarmoured dinoftagellate (Gyrodinium sp.‐A) isolated from the Oslofjord, Norway, were investigated by thin‐layer chromatography, visible light spectrophotometry, proton magnetic resonance and mass spectrometry and simple chemical reactions. Besides chlorophyll a, chlorophyll c, β,β‐carotene, diatoxanthin and diadinoxanthin, the species possessed three xanthophylls that could not be correlated with carotenoids previously reported from dinoflagellates. The main carotenoid was different from peridinin and fucoxanthin, both of which are reported as the main characteristic carotenoids in photoautotrophic dinoflagellates. No trace of peridinin could be detected in the pigment extract. A morphological description of the organism based on light microscopy is presented, and the relationship with other small gymnodinioid (Gymnodinium spp.) species is discussed. The preliminary results indicate that this Gyrodinium may be a previously undescribed species.
POTASSIUM IN POLYPHOSPHATE BODIES OF CHLORELLA PYRENOIDOSA (CHLOROPHYCEAE) AS DETERMINED BY X‐RAY MICROANALYSIS1
Authors: Adamec Jan , Peverly John H. , Parthasarathy Mandayam V. 
Published: August 2007

ABSTRACTPotassium is an important component information of polyphosphate bodies (PB) by Chlorella pyrenoidosa Chick. However, it was not detected in PB by X‐ray energy dispersive microanalyses when the specimens were subjected to a standard preparation procedure for transmission electron microscopy. Intact cells were incinerated at 350 C on stainless steel grids coated with silicon monoxide. X‐ray spectra from PB showed conspicuous peaks of energy counts in the Kα lines for phosphorus and potassium. It is proposed that potassium is a major cationic component of PB in C. pyrenoidosa grown in potassium sufficient medium.
CRITICAL LEVELS OF LIGHT AND TEMPERATURE REGULATING THE GAMETOGENESIS OF THREELAMINARIASPECIES (PHAEOPHYCEAE)1
Authors: Lüning Klaus 
Published: August 2007

ABSTRACTGametophytes of threeLaminariaspecies occurring near Helgoland, North Sea, were cultivated 4 wk in a 12:12 LD regime at different temperatures in artificial light fields, and in the sea at different water depths. In the artificial light fields underwater spectral distribution was simulated according to Jerlov water Types 5, 7, 9. Blue light in the simulated light fields amounted to 17, 12 or 4% of total quanta. The rate of vegetative growth did not depend on spectral distribution, was light‐saturated at 4–6 W · m−2, and increased with temperature up to 15 C.L. saccharina(L.) Lamour. exhibited the highest tolerance towards temperature, light and UV. Gametophytes survived 1 wk at 21 C ± 0.1, but not 22 C ± 0.1. Gametophytes ofL. hyperborea(Gunn.) Fosl. andL. digitata(Huds.) Lamour. survived 1 wk at 20 C ± 0.1, but not at 21 C ± 0.1. In sunlight, and in the light field of a xenon lamp, 50% ofL. saccharinagametophytes were killed by a quantum dose of 50 μEin · cm−2, and 100% of the plants by 90 μEin · cm−2. Approximately half of these quantum doses killed the corresponding percent of the other species gametophytes. Appreciably higher quantum doses were survived in visible light, with red being the most detrimental. Fertility depended on a critical quantum dose of blue light which decreased almost exponentially with decreasing temperature. The quantum dose (400–512 nm) required for induction of fertilization of 50% of the female gametophytes (males react similarly) was 90 μEin · cm−2at 5 C, 110 μEin · cm−2at 10 C, 230 (560 inL. digitata)μEin · cm−2at 15 C, and 560 (L. hyperborea)or about 850 (other 2 species) μEin · cm−2at 18 C. In the sea the gametophytes survived the dark winter months in the unicellular stage, with almost no vegetative growth of the primary cell, due to lack of light. In early spring the female gametophytes matured in the unicellular, and the males in a few‐celled stage at the depth of 2 m, as did the laboratory cultures under conditions inducing maximal fertility.
RELATIONSHIP BETWEEN NUCLEO‐CYTOPLASMIC RATIO AND FINAL CELL VOLUME IN MICRASTERIAS CRUX‐MELITENSIS (DESMIDIACEAE, CHLOROPHYTA)1
Authors: Sana Momoyo , Ueda Katsumi 
Published: August 2007

ABSTRACTIn Micrasterias crux‐melitensis (Ehrbg.) Hass., small parental half‐cells produced daughter half‐cells larger than themselves. As the volume of the parental half‐cells decreased, the volume ratio of daughter to parental half‐cells increased; the larger the nucleo‐cytoplasmic ratio of parental half‐cells, the larger the volume of the daughter half‐cells. Small daughter half‐cells grew larger than expected when cytoplasm of other cells was incorporated. The number of dictyosomes was almost the same for cells of different volumes. Results obtained seem to suggest that the volume of daughter cells is determined by the balance between the gradient of mRNA and the quantity of cytoplasm.
FINE STRUCTURE OF CALONEIS AMPHISBAENA (BACILLARIOPHYCEAE)1
Authors: Edgar Lesley A. 
Published: August 2007

ABSTRACTThe structure of the motile pennate diatom Caloneis amphisbaena Cleve is described, with emphasis on the lateral, lobed pyrenoid with neither a limiting membrane nor penetration by thylakoids, an interphase nucleus with centers of condensed chromatin, paired dictyosomes, and mitochondria cradled within the chambers of the valve. Microfilaments forming two bundles which lie beneath each raphe slit are of the same size and appearance as actin microfilaments associated with other motile systems.
A GRADIENT IN BENTHIC INTERTIDAL ALGAL ASSEMBLAGES ALONG THE SOUTHERN CALIFORNIA COAST1
Authors: Thom Ronald M. 
Published: August 2007

ABSTRACTBased on an analysis floristic data, a gradient appears to exist in the composition of intertidal algae along the 450 km of southern California coastline immediately south of Point Conception. Reciprocal averaging ordination of the algal flora at 51 sites in this area suggests that the gradient is not strictly latitudinal. Variation from a latitudinal gradient occurs ca. 60‐80 km south of Point Conception. An ordination of frequently occurring species indicated that compositional changes are substantial when sites at the extreme north and south are compared, but that the changes are gradual and continuous. Possible explanations for the gradient are discussed, and these include: sea temperature, upwelling, sand movement, human disturbance (i.e., pollution, trampling), and wave action.
ELECTROPHORETIC ANALYSIS OF GENETIC VARIATION IN THE CHAROPHYTA. I. GENE DUPLICATION VIA POLYPLOIDY1
Authors: Grant Michael C. , Proctor Vernon W. 
Published: August 2007

ABSTRACTElectrophoretic analysis of 12 species ofCharaindicates that functional gene duplication via polyploidy has commonly occurred in the genus. Duplication has been followed by differentiation of the loci encoding phosphoglucose isomerase (PGI). This has led directly to generation of substantial levels of genie variation both within and between taxa. A simple genetic model is proposed to account for the large array of PGI phenotypes encountered in natural populations. Constraints imposed by the reproductive biology of members of the genus, such as selfing, appear to have resulted in selective premiums on intrinsic mechanisms of generating genetic variation. Levels of variation in PGI were higher than would be predicted on the basis of charophyte reproductive characteristics; haploid loci segregate approximately two alleles within each species.
PERIODICITY OF EPIPELIC UNICELLULAR VOLVOCALES (CHLOROPHYCEAE) IN A SHALLOW ACID POOL1
Authors: Happey‐Wood Christine M. 
Published: August 2007

ABSTRACTThe occurrence, periodicity and growth of twenty species of unicellular Volvocales on sediments in an acidic pool are described. Minimum populations were recorded in winter, but during the rest of the year standing crops fluctuated rapidly. The greatest species diversity and primary productivity occurred in late spring‐early summer and in autumn, when maximum numbers of Chlamydomonas spp. and Chloromonas spp. increased exponentially on the sediments. The chlamydomonads were more numerous in the epipelon than other major algal components such as diatoms, euglenoids, bluegreen algae and desmids. Growth of the chlamydomonad population occurred after the period of maximum diatom standing crop. Evidence shows that rates of primary production were greater in late spring and late summer when species diversity and standing crop or apparent growth rates of unicellular Volvocales were high. Thus these algae which are normally neglected may be more important in primary productivity than previously believed since they grow during periods when larger algae are scarce. Analysis of the data using the multivariate technique of Reciprocal Averaging confirmed seasonal periodicity in this community of epipelic flagellates. It also identified species with distinctive ecological requirements. A relationship between the bicarbonate‐alkalinity of the overlying water and the chlamydomonad population was demonstrated by ordination analysis.
OLISTHODISCUS LUTEUS (CHRYSOPHYCEAE). IV. EFFECTS OF LIGHT INTENSITY AND TEMPERATURE ON PHOTOSYNTHESIS, AND CELLULAR COMPOSITION1
Authors: Tomas Carmelo R. 
Published: August 2007

ABSTRACTThe effect of light intensity and temperature on photosynthesis, chlorophyll a, and cellular concentrations of nitrogen and carbon in an axenic clone of Olisthodiscus luteus Carter following incubation in both indoor and outdoor growth chambers was determined. Populations were grown outdoors and photosynthesis determined in a graded series of light intensities yielding 4–524 total ly (per 6 h) and temperatures from 5 to 23 C and indoors at 0.3–40 total ly and 5–30 C. In both series, photosynthesis was saturated at low light (∼10 total ly or 0.028 ly · min −1) and showed only slight inhibition at the higher light intensities. Chlorophyll a·cell−1 had a maximum at 15 C with declining values at extremes of temperature. Carbon and nitrogen were more variable between indoor and outdoor experiments. Populations incubated indoors increased their carbon (130–225 pg·cell−1) and nitrogen (23–35 pg·cell−1) content as a function of light and temperature from 5 to 20 C. The outdoor series had increases in cellular N and C as a function of light and temperature below 14 C but maximum C·cell−1 (175 pg) and N·cell−1 (>27 pg) as well as wide variations in assimilation number occurred between 14–21 C. Assimilation numbers (<1.0–4.7) were similar to those measured in natural populations. Ratios for C and N had a similar relationship in both indoor and outdoor experiments. Growth calculated from photosynthesis results agreed with growth based on cell number for the 24 h period preceding incubations in the indoor series but was consistently overestimated in the outdoor series. The low light saturation indoors, lack of inhibition at high intensities, and variations between 14–21 C in the outdoor series suggest features important to survival of O. luteus in natural waters.
A MORPHOLOGICAL STUDY OF FIMBRIFOLIUM, A NEW GENUS IN THE CYSTOCLONIACEAE (GIGARTINALES, RHODOPHYTA)1
Authors: Hansen Gayle I. 
Published: August 2007

ABSTRACT Fimbrifolium is described as a new genus for the taxon, Rhodophyllis dichotoma (Lepechin) Gobi. Vegetatively, Fimbrifolium dichotomum is similar to some species of Rhodophyllis and Craspedocarpus, but reproductively it differs from these genera in three main features: the carposporophyte develops with the first gonimoblast initial produced in an outward direction away from the axis; at maturity, the carposporophyte consists of a central fusion cell with outwardly radiating chains of carposporangia and inwardly radiating nutritive filaments; and, in the mature tetrasporophyte, tetrasporangia are borne in an intercalary position in cortical rosette‐filaments. The relative importance of these features as generic characteristics in the family is discussed.
SYSTEMATICS OF THE ZYGNEMATACEAE (CHLOROPHYCEAE). II. ZYGOSPORE‐WALL STRUCTURE IN SIROGONIUM AND A TAXONOMIC PROPOSAL1
Authors: Hoshaw Robert W. 
Published: August 2007

ABSTRACTZygospore‐wall structure is described for nine species of Sirogonium using the light microscope and scanning electron microscopy (SEM) on spores from cultures and on glycerin‐preserved spores from field collections. Zygospores possess four distinctive wall layers with the innermost and outermost smooth and composed of cellulose. The two median wall layers are pigmented and the innermost of these may be conspicuously ornamented as in Sirogonium ceylanicum Wittrock, S. hui (Li) Transeau, S. melanosporum (Randhawa) Transeau, S. ventersicum Transeau, S. pseudofloridanum (Prescott) Transeau and S. illinoisense (Transeau) G. M. Smith. Inner median wall layers of S. floridanum (Transeau) G. M. Smith, S. sticticum (J. E. Smith) Kützing and S. tenuis (Nordstedt) Transeau lack distinctive ornamentation, but possess minor depressions or small raised areas on their surfaces. Types of ornamentation revealed by SEM are compared with earlier light microscope observations and the interpretations from SEM are used to construct improved taxonomic keys to Sirogonium.
FORMATION OF RESTING SPORES BY LEPTOCYLINDRUS DANICUS (BACILLARIOPHYCEAE) IN A CONTROLLED EXPERIMENTAL ECOSYSTEM1
Authors: Davis Curtiss O. , Hollibaugh James T. , Seibert Don L. R. , Thomas William H. , Harrison Paul J. 
Published: August 2007

ABSTRACT Leptocylindrus danicus Cleve became the dominant phytoplankton species, comprising 70–80% of the total assemblage, in one of the CEPEX Controlled Experimental Ecosystems (CEE) at Saanich Inlet, British Columbia (Canada). In the first week of June, when nitrate levels were reduced below 0.5 μm, the majority of the L. danicus cells present in the CEE formed resting spores. The spores were heavily armored with spines and appeared to sink unmolested to the bottom of the CEE. Four continuous cultures were started with an inoculum from the CEE and, in a 24 h period when N became depleted, 86% of the L. danicus present (∼80% of the total phytoplankton assemblage) formed resting spores. A daily dilution culture with nutrients kept at saturating levels was started at the same time from the same inoculum and continued for 2 wk beyond the spore formation event in the N‐limited cultures. No spores were observed in the nutrient‐saturated culture, indicating that N limitation was necessary to trigger spore formation. Spores were kept in the dark at 3 and 10 C. After 36 and 97 days, a large percentage of the spores germinated. After 214 days, >1% of the spores were still capable of germination. Laboratory studies with L. danicus isolated from the CEE confirmed that N limitation was the primary factor triggering spore formation. Microscope observations of these cultures indicated that the spores were formed by auxospores following sexual reproduction.
DIATOM MINERALIZATION OF SILICIC ACID. V. ENERGETIC AND MACROMOLECULAR REQUIREMENTS FOR Si(OH)4 MINERALIZATION EVENTS DURING THE CELL CYCLE OF NAVICULA PELLICULOSA1
Authors: Sullivan Cornelius W. 
Published: August 2007

ABSTRACTThe reactions and processes which underlie the silicification mechanism (incorporation of soluble pool Si into insoluble material) in the diatom Navicula pelliculosa (Bréb.) Hilse are quite sensitive to low temperature. Furthermore incorporation is completely blocked in 66Ge‐Si(OH)4 preloaded cells treated with an inhibitor of oxidative phosphorylation (2,4‐dinitrophenol) or a sulfhydryl blocking agent (N ‐ethylmaleimide). De novo protein synthesis is not required for incorporation in cells preloaded 3 h, but cycloheximide added to cells preloaded 1 h inhibits incorporation after 2 h. These results are interpreted to indicate that purely chemical reactions, which are uncoupled from cellular metabolism, cannot completely account for Si(OH)4 polycondensation during silica frustule morphogenesis in the diatom. A temperature sensitive cellular process or reaction, postcytokinesis, is also postulated to be required before silicification can occur.