bluuebunny/crossref_metadata_2025 huggingface dataset:
LIGHT AND NUTRIENT LIMITATION OF SEA‐ICE MICROALGAE (HUDSON BAY, CANADIAN ARCTIC)1
Authors: Gosselin Michel , Legendre Louis , Therriault Jean‐Claude , Demers Serge
Published: October 2004

Changes in the biochemical composition of sea‐ice microalgae (southeastern Hudson Bay, Canadian Arctic) were used to assess the light and nutrient status of cells growing at the ire‐water interface. These changes allowed us to test the hypothesis that ire algae are limited by light at the beginning of their growth season and become periodically limited by nutrients as the season progresses. During the vernal growth season, three patterns of variation in cellular components were found in response to changes in environmental conditions. 1) Chlorophyllsaandc,ATP, carbohydrate, and carbon followed the seasonal increase in under‐ice irradiance, which was mainly mused by melting of the snow cover. 2) Dissolved and biogenic silicon underwent periodic variations, which were coupled to the fortnightly neap‐spring cycle of tidal mixing. 3) Cellular contents of free amino acids, protein, and total nitrogen remained relatively constant during the season. An early decrease in intracellular chlorophyllsaandcsuggests that ire algae did respond to small changes in solar irradiance by changing the pigment composition of their photosynthetic units. Seasonal increases in ATP, carbohydrate, and total carbon indicate light limitation in April, followed in May by a period of excess irradiance and/or nutrients in short supply. The seasonal increase in ATP and the high values of the ratio free amino acids: protein show that neither phosphorus nor nitrogen limited algal growth at the ire‐water interface. In May, higher values of carbohydrate: protein, carbon: nitrogen, carbon: chlorophylla,and also carbon: silicon and ATP: silicon indicate that the ice algae became silicon‐deficient in their natural environment. Following a period of light limitation, at the beginning of the season, ice‐algal growth became silicon‐limited, when in situ irradiance and the accumulated algal biomass were high and the tidally‐driven nutrient supply was not strong enough to satisfy algal nutrient requirements.
PHOTOSYNTHETIC RESPONSES TO LIGHT AND TEMPERATURE OF THE HETEROMORPHIC MARINE ALGAMASTOCARPUS PAPILLATUS(RHODOPHYTA)1
Authors: Zupan John R. , West John A.
Published: October 2004

Physiological differentiation of the heteromorphic life‐history phases of the red algaMastocarpus papillatus(C. Agardh) Kützing was assessed. Photosynthetic responses to light and temperature of the erect, foliose gametophyte were compared to those of the crustose tetrasporophyte. Plants of both phases were collected from four locations on the Pacific coast of Baja California, Mexico, and California, USA, between 32–4l° N latitude. Within each location, the chlorophyll‐specific, light‐saturated photosynthetic rates of gametophytes were generally five times greater than those of tetrasporophytes. Initial slopes of photosynthesis: irradiance curves were greater for gametophytes than for tetrasporophytes. The crust and the blade from each location were similar with respect to dark respiration rates. For tetrasporophytes from all locations, the photosynthetic temperature optima were between 12–15° C. The photosynthetic temperature optima for gametophytes ranged from 15–17° C for plants from Trinidad Head (41° N) to 22–25° C for plants from Punta Descanso (32° N). Both gametophytes and tetrasporophytes from the northernmost location had significantly higher photosynthetic rates than the same phase from the other three locations. The photosynthetic responses to light support models for the life history in which life history phases have different ecological roles. The gametophyte, thought to be specialized for rapid growth and competition, may allocate more resources to photosynthetic machinery, hence the higher maximum photosynthetic rates. The tetrasporophyte, thought to be specialized for resistance to herbivores, may allocate more resources to structural or chemical defenses in preference to photosynthetic machinery. Consequently, the tetrasporophyte has lower photosynthetic capacity.
INFLUENCE OF VARIOUS EXPOSURE PERIODS ON THE BIOMASS AND CHLOROPHYLL A OF CLADOPHORA GLOMERATA (CHLOROPHYTA)1
Authors: Usher Howell D. , Blinn Dean W.
Published: October 2004

The biomass of Cladophora glomerata (L.) Kütz. was estimated at selected sites in the Colorado River between Glen Canyon Dam, Arizona, and River Kilometer 354. C. glomerata biomass was significantly higher at sites above Lees Ferry (25 km downstream from the Dam) than sites below the Ferry. Biomass and chlorophyll a were significantly reduced when C. glomerata was subjected to one‐time exposures to the atmosphere for 12 daylight h in more. Repeated 12/12 h and 24/24 h (exposure/submergence) cycles over a two‐week period also showed a significant reduction in biomass. The adaptations of C. glomerata to “stranding” during regulated flows are discussed.
CHANGES IN CELL CHEMICAL COMPOSITION DURING THE LIFE CYCLE OF SCRIPPSIELLA TROCHOIDEA (DINOPHYCEAE)1
Authors: Lirdwitayaprasit Thaithaworn , Okaichi Tomotoshi , Montani Shigeru , Ochi Tadashi , Anderson Donald M.
Published: October 2004

The cellular content of carbon, nitrogen, amino acids, polysaccharides, phosphorus and adenosine trtphosphate (ATP) was determined at several stages during the life cycle of the dinoflagellate Scrippsiella trochoidea (Stein) Loeblich. Carbon per cell decreased slightly between exponential and stationary phase growth in vegetative cells whereas nitrogen per cell did not change. Both of these cellular components increased markedly on encystment and then decreased to vegetative cell levels during dormancy and germination. C/N ratios increased gradually during cyst dormancy and activation, reflecting a more rapid decrease in N than in C pools, even though both decreased through time. Amino acid composition was relatively constant during the vegetative cell stages; glutamic acid was the dominant component. Arginine was notably higher in cysts than in vegetative cells but decreased significantly during germination, suggesting a role in nitrogen storage. The ratio of neutral ammo acids to total ammo acids (NAA/TAA) decreased as cysts were formed and then gradually increased during storage and germination. The ratio of basic ammo acids to total ammo acids (BAA/TAA) changed in the opposite direction of NAA/TAA, whereas the ratio of acidic acids to total amino adds (AAA/TAA) was generally invariant. Ammo acid pools were not static during the resting slate in the cysts: there was degradation or biosynthesis of certain, but not all, classes of these compounds. The monosacchande composition of cold and hot water extracted polysaccharides was quite different between cells and cysts. A high percentage of glucose in cysts suggests that the storage carbohydrate is probably in the form of glucan. Total cellular phosphorus was higher in all cyst stages than in vegetative cells. However, ATP‐cell−1 decreased as vegetative cells entered stationary phase and encysted, and continued to decrease in cysts during dark cold storage. ATP increased only as the cysts were activated at warm temperatures in the light and began to germinate. The above data demonstrate that dormancy and quiescence are not periods of inactive metabolism but instead are times when numerous biochemical transformations are occurring that permit prolonged survival in a resting state.
FREEZE‐FRACTURE STUDY OF THE SINGLE MEMBRANE BETWEEN HOST CELL AND ENDOCYTOBIONT IN THE DINOFLAGELLATESGLENODINIUM FOLIACEUMANDPERIDINIUM BALTICUM1
Authors: Eschbach Stefan , Speth Volker , Hansmann Paul , Sitte Peter
Published: October 2004

The dinoflagellatesGlenodinium foliaceumStein andPeridinium balticum(Levander) Lemmermann harbor a chrysophytic endocytobiont which is bounded by only a single membrane. This unique membrane is of particular interest because it could correspond to an intermediate stage in the evolution of “complex” plastids found in many Plastids of this type are surrounded by three or membranes instead of the usual two. With freeze‐fracture techniques, we show that the single membrane inP. balticumhas a pronounced polarity with respect to the distribution of intramembrane particles (IMPs) on the two corresponding fracture faces. The inner face exhibited more IMPs than the outer. We suggest that this stdedness identifies the separating membrane as the plasma membrane of the endocytobiont. A symbiontophoric vacuole with a separate membrane apparently is lacking. In the endocytobiosis ofG. foliaccum,the single membrane separating host and endocylobiont exhibits a symmetrical particle partition. Nevertheless, from the size distribution of the IMPs it appears likely that this membrane, too, corresponds to the plasma membrane of the symbiont.
RESTRICTION ENZYME ANALYSIS AND CLONING OF HIGH MOLECULAR WEIGHT GENOMIC DNA ISOLATED FROM CHLORELLA SOROKINIANA (CHLOROPHYTA)1
Authors: Cock J. Mark , Roof Lori L. , Boscomb Newell F. , Gehrke Charles W. , Kuo Kenneth C. , Schmidt Robert R.
Published: October 2004

High molecular weight (50–70 kb) genomic DNA was isolated from the eukaryotic green alga, Chlorella sorokiniana spec. nov, (formerly Chlorella pyrenoidosa Chick, strain 7‐11‐05), for restriction endonuclease digestion studies and for preparation of a genomic DNA library. Twenty restriction endonucleases were examined for their abilities to digest this DNA. Nine of the endonucleases gave nearly complete digestion of the DNA, whereas 11 gave only partial digestion. Additional purification steps to remove possible contamination by proteins, RNAs, or polysaccharides did not improve digestion. Digestion studies with pairs of endonuclease isoschizomers, of which one member was sensitive to base methylation, suggested that 5‐methylcytosine might be responsible Jor inhibition of certain endonucleases. Analysis of the DNA showed it to contain 63% GC and to have a high content (5.1 mol %) of 5‐methylcytostne but no other methylated or unusual bases. Evidence indicates that this high 5‐methylcytosine content, which is a characteristic of higher plant genomic DNA rather than of eukaryotic microorganisms, interfered with the cloning of restriction fragments (or fragments produced by mechanical shearing) of C. sorokiniana genomic DNA in standard bacterial host‐strains. Escherichia coli strain K803, which is a permissive host for cloning highly methylated DNA from higher plants, also permitted the cloning of a complete genomic library of 15–20 kb Mbol restriction fragments inserted into the BamHI site of the γ vector, EMBL 3. This C. sorokiniana genomic library appears to be the first genomic‐library constructed for any species of Chlorella.
OCCURRENCE OF GLYCOLATE OXIDASE AND HYDROXYPYRUVATE REDUCTASE IN EGREGIA MENZIESII (PHAEOPHYTA)1
Authors: Gross Wolfgang
Published: October 2004

Glycolate oxidase and hydroxypyruvate reductase, two key enzymes of glycolate metabolism, are present in the brown alga Egregia menziesii (Turn.) Aresch. The pH optimum and Km for the partially purified glycolate oxidase are similar to the enzyme from higher plants, Charophyta and Xanthophyta, whereas the substrate specificity is different from the higher plant enzyme.
EFFECTS OF WOUNDING BY THE HERBIVOROUS SNAILS LITTORINA SITKANA AND L. SCUTULATA (MOLLUSCA) ON GROWTH AND REPRODUCTION OF THE INTERTIDAL ALGA FUCUS DISTICHUS (PHAEOPHYTA)1
Authors: Van Alstyne Kathryn L.
Published: October 2004

Small (3–7 cm long) Fucus distichus ssp. edentatus (de la Pyl.) Pow. Plants were tagged at three sites in which densities of the herbivorous snails Littorina sitkana and L. scutulata ranged from 367–4690 animals · M‐2. From April–August 1986, the growth rate, degree of wounding, and reproductive status of individual thalli were monitored at 2–4 week intervals. Grazer‐inflicted damage to the thalli varied within and among sites. Mean growth rates at the site with low densities of littorines were about twice those at the site with intermediate densities and about four times those at the high density site. At the site with high densities of littorines, F. distichus growth rates were negatively correlated with the degree to which the plants were wounded. There appeared to be no correlation of grazer density with F. distichus survivorship. Thalli at the site with few herbivores tended to reproduce earlier and at a larger size than did those at the other two sites. In all three areas, only thalli that had received little damage from herbivores became reproductive. By lowering growth rates and delaying reproduction in F. distichus, grazing by littorine snails can potentially cause variation in reproductive output among individual thalli.
INTERTIDAL AMPHIPODS AS POTENTIAL DISPERSAL AGENTS OF CARPOSPORES OF IRIDAEA LAMINARIOIDES (GIGARTINALES, RHODOPHYTA)1
Authors: Buschmann Alejandro H. , Bravo Andrés
Published: October 2004

Mid and late successional benthic algae have poor dispersal capacities. Mobile herbivores may increase dispersal of some algae because spores can survive digestion by grazers and stick to external body appendages. We show that carpospores are the only type of reproductive unit of the rhodophyte Iridaea laminarioides Bory that survive passage through the digestive tract of the amphipod Hyale sp. The spores also stick to the amphipods' legs and are thus carried by the amphipods in the field. Amphipods significantly increased (P < 0.01) the number of spores settling on artificial substrata in places where barriers prevented the normal ingress of algal propagules. The presence of artificial substrata that act as a refuge for the grazers also caused an increase (P < 0.01) in the number of settled spores. Amphipods also significantly increased (P < 0.01) the number of spores under an Ulva sp. canopy in laboratory experiments.
EXOGENOUS SOURCES OF INORGANIC CARBON FOR PHOTOSYNTHESIS BY MARINE MACROALGAE1
Authors: Maberly Stephen C.
Published: October 2004

Thirty‐five species of marine macroalgae were tested for their ability to remove inorganic carbon from seawater using the pH‐drift technique. Six of these species, all Rhodophyta, were unable to use HCO3–. The remaining species exhibited a range in ability to use HCO3– and deplete inorganic carbon (Cτ); the three most effective species, all Chlorophyta, raised the pH to over 10.50, depleted the concentration of CO2 effectively to zero, and depleted the concentration of Cτ to less than 50% of that at air‐equilibrium. In contrast, the six species restricted to CO2 did not raise the pH above 9.0 at a CO2 concentration of about 1.5 μmol · L‐1 and depleted the concentration of Cτ to about 80% of that at air‐equilibrium.

Ability to raise pH and deplete Cτ was linked to the habitat in which the species grew. Five of the six species which lack the ability to use HCO3– grow subtidally in relatively low light beneath a canopy of larger Phaeophyta. None of these species grow in rockpools where carbon‐depletion may occur. Species from rockpools were all effective at removing inorganic carbon. Competition for Cτ may be one of the factors that determines species composition in rockpools.

There was a species‐specific difference between the calculated concentration of Cτ at the end of a pH‐drift experiment and that measured directly. Most, but not all, species with the ability to generate high pH‐values showed a lower than calculated final concentration of Cτ consistent with precipitation of CaCO3. A number of Rhodophyta with no, or a limited, ability to use HCO3– showed the opposite response, with final concentrations of Cτ exceeding that calculated from the pH.

Calculations based on the maximum gross rate of production of CO2 from HCO3– in the absence of external carbonic anhydrase confirmed the results of the pH‐drift experiments by demonstrating HCO3– ‐use in Monostroma fuscum (Post et Rupr.) Wittr. And Ulva lactuca L. and the lack of this ability in Lomentaria articulate (Huds.) Lyngb. Rates of net photosynthesis at air‐equilibrium were greater than 95% of those at 2.3 mmol Cτ· L‐1 for many of the species which were able to use HCO3–, but on average only 72% for the six species restricted to CO2.
EFFECTS OF LIGHT AND WAVE DISTURBANCE ON VERTICAL ZONATION OF ATTACHED MICROALGAGE IN A LARGE RESERVOIR1
Authors: Hoagland Kyle D. , Peterson Christopher G.
Published: October 2004

Experimental field manipulations of artificial substrata were used to examine the mechanisms controlling attached algal zonation down the face of the dam in Lake McConaughy, a large reservoir in western Nabraska. Sets of clay tiles were incubated in the upper (2.5 m depth) and lower (8 m depth) growth zones for two weeks. Five sets tiles were then switched from the upper to the lower growth zone and vice versa. Five additional sets of tiles were switched to the lower zone and artificially disturbed. Diatom cell densities increased rapidly in both the zones; however, wind‐induced turbulence caused dramatic declines (up to 61%) in densities in the upper zone. Consequently, cell densities in the upper and lower growth zones were not significantly different after four weeks, despite the 17–30% higher light levels in the upper zone. Based on cell densities and relative abundances on clay tiles and naturally occurring rocks, 26 of the 32 most common diatom taxa had a significant upper (10) or lower (16) zone preference. Of these, 15 taxa exhibited a consistent response to one or both switching manipulations, confirming a growth zone preference, and two showed a clear preference for disturbed substrata. Diatom growth form appeared to play a major role in determining the vertical zonation of attached communities, since actively motile taxa exhibited a lower zone preference and stalked forms occurred primarily in the upper zone. The present study indicates that light attenuation and wave disturbance are primary mechanisms that control the vertical zonation of freshwater epilithic algae.
DISTRIBUTION AND ALGAL‐LYSING ACTIVITY OF FRUITING MYXOBACTERIA IN LAKE SUWA1
Authors: Yamamoto Yoko , Suzuki Kenji
Published: October 2004

The seasonal distribution of fruiting myxobacteria, which are able to lyse cyanobacteria in the water and sediments of eutrophic lakes, was determined periodically in 1985 and 1986. Fruiting myxobacteria isolated from sediments of these sites were found to have a lytic effect on a wide variety of cyanobacteria. The myxobacterium isolate designated as S‐1‐8 was identified as Myxococcus fulvus Cohn. Lytic activity for cyanobacteria was produced during growth of the organism in a number of complex media. The maximal amount of activity was produced in casitone‐yeast media and at the end of the log phase of growth.
EFFECTS OF LONG TERM EXPOSURE TO LOW TEMPERATURE ON THE PHOTOSYNTHETIC APPARATUS OFDUNALIELLA TERTIOLECTA(CHLOROPHYCEAE)1
Authors: Levasseur Maurice E. , Morissette Jean‐Claude , Popovic Radovan , Harrison Paul J.
Published: October 2004

The effects of long term exposure to suboptimal growth temperature on the photosynthetic apparatus ofDunaliella tertiolectaButcher were investigated using carbon fixation rate versus irradiance curves and the variable fluorescence induction method. Carbon fixation rates per unite chlorophyll a at saturating (pBm) and subsaturating (αB) irradiances were 55% and 39% lower, respectively, at 12° C than at 20° C. Chlorophyll a quotas and the spectrally averaged in vivo absorption cross section normalized to chlorophyll a (a*) were not significantly different at these two temperatures. Analysis of the fluorescence kinetics revealed 1) no significant variations of the amount of PSII photoactive reaction centers per unit chlorophyll a, 2) a 14% decrease of the PSII quantum yield(+) and 3) a 29% decrease of the energy transfer efficiency between the light harvesting chlorophyll a pigment bed and the PSII reaction centers. The decrease in energy transfer efficiency between the antennae and the PSII reaction centers at 12° C was interpreted as a mechanism to avoid photoinhibition.
STEROLS OF DICTYOCHA FIBULA (CHRYSOPHYCEAE) AND OLISTHODISCUS LUTEUS (RAPHIDOPHYCEAE)1
Authors: Patterson Glenn W. , Van Valkenburg Shirley D.
Published: October 2004

Sterols from cultured Dictyocha fibula Ehrenberg and Olisthodiscus luteus Carter were extracted and identified for comparison with sterols from other Chromophycota species. Although orientation at C‐24 was not absolutely determined, the sterols of Dictyocha, a silicoflagellale, appeared to consist of only 24‐methyl‐22‐dehydrocholesterol and 24‐methylenecholesterol, a sterol composition not known in any other alga. This is in keeping with the taxonomic isolation Dictyocha has among algae. On the other hand, Olisthodiscus luteus contained 24‐ethylcholesterol, 24‐ethylcholestanol, 24‐methylcholesterol, and cholesterol. This composition is in accord with sterols of members of the Xanthophyceae and Raphidophyceae.
UNIQUE CHLOROPLAST GENOME IN SPIROGYRA MAXIMA (CHLOROPHYTA) REVEALED BY PHYSICAL AND GENE MAPPING1
Authors: Manhart James R. , Hoshaw Robert W. , Palmer Jeffrey D.
Published: October 2004

The choroplast genome in Spirogyra maxima (Hassall) Kützing is 130 kb in size and locks large repeat units. The 16S and 23S rRNA genes are separated by approximately 44 kb, which makes co‐transcription of these genes unlikely. Spirogyra maxima is unusual among green algae in that its chloroplast genome apparently does not contain the tufA gene, the absence of which is characteristic of land plant chloroplast DNAs. Apart from three groups of genes, pasA‐psaB, psbC‐psbD, and atpA‐atpF/H, which are co‐transcribed in land plants and also map together in S. maxima chloroplast DNA, the S. maxima gene order overall is unlike that of any other chloroplast genome.
PLASTID DNA RESTRICTION ANALYSIS LINKS THE HETEROMORPHIC PHASES OF AN APOMICTIC RED ALGAL LIFE HISTORY1
Authors: Parsons Thomas J. , Maggs Christine A. , Douglas Susan E.
Published: October 2004

Gymnogongrus sp. (Phyllophoraceae) from Nova Scotia, Canada, identified tentatively as G. devoniensis (Greville) Schotter, grows in association with an Erythrodermis‐like that forms chains of tetrasporangia or bisporangia. The crust resembles tetrasporophytic phases of other Gymnogongrus species, but in culture both it and the G. devoniensis gametophytes cycle independently by apomictic reproduction.

A method was developed for extracting organelle DNA from this carrageenophyte genus involving purification of nucleic acids by binding to hydroxylapatite. Plastid DNA from G. devoniensis and bisporangial Erythrodermis‐like crusts was compared with that of G. devoniensis and G. crenulatus (Turner) J. Agardh from France and of G. furcellatus (C. Agardh) J. Agardh from Chile. Plastid genomes of all Gymnogongrus species and the Erythrodermis‐like crust were approximately 175 kb long. A single 3.5‐kb plasmid DNA species was found in G. devoniensis and the Erythrodermis‐like bisporophyte but not in other samples. Digestion of plasted DNA with several restriction endonucleases produced identical patterns in G. devoniensis and the Erythrodermis‐like bisporophyte from the same location, indicating clearly that these entities represent two phases of an uncoupled life history. These results were confirmed with heteologous probes. A restriction fragment length polymorphism was identified between two Nova Scotian G. devoniensis populations. There was no similarity in restriction patterns between G. devoniensis from Nova Scotia, G. devoniensis from France. G. crenulatus or G. furcellatus, suggesting that molecular taxonomic methods could be important in delineating members of this morphologically variable genus. Further study is necessary to determine whether either Nova Scotian G. devoniensis or French G. devoniensis corresponds to type populations of G. devoniensis from Devon, England.
NUCLEOTIDE SEQUENCE OF THE GENE FOR THE LARGE SUBUNIT OF RIBULOSE‐1.5‐DISPHOSPHATE CARBOXYLASE/OXYGENASE FROM CRYPTOMNASΦ EVIDENCE SUPPORTING THE POLYPHYLETIC ORGIN OF PLASTIDS1
Authors: Douglas Susan E. , Durnford Dion G. , Modern Clifford W.
Published: October 2004

The Chloroplast‐encoded gene for the large subunit of ribulose‐1, 5‐bisphosphate carboxylase/oxygenase (Rubisco) from the marine chlorophyll c2‐, phycobiliprotein‐containing alga, Cryptomonas φ was cloned, sequenced and compared to representatives from other groups of photosynthetic organisms. The coding sequence was 1464 base pairs(bp) and encoded a polypeptide of 488 amino acids. The small subunit of Rubisco was located 83 bp 3′ to the large subunit and was co‐transcribed. A 5 bp sequence, 5′ of the initiator methionine codons of both the large and small subunits, may represent ribosomal binging sites. The start of transcription was identified by primer extension studies and putative promotor sequences were found. This study is the first report of the sequence for the large subunit of Rubisco from a chromophyte alga, and its potential as phylogenetic indicator for algal plastids sis discussed.
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGAXIPHOPHORA GLADIATASSP. GLADIATA (PHAEOPHYTA). I. PARTITIONING OF MORPHOLOGICAL CARIATION INTO SPATIAL SCALES1
Authors: Rice Ellen L. , Kenchington Trevor J.
Published: October 2004

The geographic expression of morphological variation inxiphophora gladiatassp.gladiatawas examined throughout the range of the taxon. The spatial scales on which this variation occurred were identified using nested analyses of variance (ANOVA) on 14 morphometric characters from 1224 plants collected at 12 sites. These characters were remarkably homogeneous in the scales at which their variation was expressed. The greater part of the morphological variation inX. gladiatassp.gladiata(over 90% for most characters was expressed between adjacent primary clumps; that is, over scales of about 100 mm. Since it was previously shown that the clumps of plants are themselves spatially discrete, the spatial expression of morphology in this taxon forms a true mosaic with abrupt between‐cells boundaries. Much of the remaining variation in most characters was expressed at a scale of about 300 km. At intermediate scales, that is, over a few meters and (in most characters) a few kilometers, there appears to be negative additional variance. In effect, the mixture of clumps at these scales tends to be a uniform rather than a random selection of the available morphological variety of clumps within each region. This observed pattern is compared and contrasted with those previously found in the confamilial speciesFucus distichusandF. evanescens.
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGA XIPHOPHORA GLADIATA SSP. GLADIATA (PHAEOPHYTA). II. MORPHOLOGICAL VARIATION OVER LARGE SPATIAL SCALES1
Authors: Rice Ellen L. , Kenchington Trevor J.
Published: October 2004

The geographic expression of inter‐regional morphological variation in Xiphophora gladiata ssp. gladiata was examined using a combination of discriminant function analyses, canonical correlation analysis and linear regression analysis. The pattern of that expression is an irregularly‐stepped cline over scales of hundreds of kilometers, superimposed on a weak complex of microclines driven by exposure and (perhaps) other locally‐varying environmental factors. The large‐scale irregular cline is probably a response to the physico‐chemical characteristics of regional water masses.
LAGERHEIMIA HINDAKII IS THE UNICELLULAR STAGE OF A SCENEDESMUS1
Authors: Trainor Francis R. , Egan Patrick F.
Published: October 2004

Extensive variability in spine number and position was emphasized in the protologue for the spiny unicell Lagerheimia hindakii Hegew. et A. Schmidt. Using an axenic clone established from culture Hindk 1975/95, which provided the type material of that organism, we initiated a morphogenetic study. While in the unicellular stage, three short spines were usually formed at each cell pole. A colonial morph was first observed during the initial isolation procedure after unicells were dispersed on firm agar and allowed to grow. We propose that L. hindakii is a Scenedesmus, close to S. subspicatus R. Chod. This organism is unlike most representatives of the genus Scenedesmus because colonies do not readily appear in dilute media; they also fail to form in Bristol's liquid medium unless there is an organic supplement, e.g. glucose. Hindk 1975/95 may be more closely related to truly unicellular taxa than to other Scenedesmus.
MORPHOLOGIC DETAILS OF SIX BENTHIC SPECIES OF PROROCENTRUM (PYRROPHYTA) FROM A MANGROVE ISLAND, TWIN CAYS, BELIZE, INCLUDING TWO NEW SPECIES1
Authors: Faust Maria A.
Published: October 2004

Two new dinoflagellate species, Prorocentrum hoffmannianum and Prorocentrum ruetzlerianum, and four known species, Prorocentrum emarginatum Fukuyo 1981, Prorocentrum mesicanum Tafall 1942, Prorocentrum concavum Fukuyo 1981, and Prorocentrum lima (Ehr.) Dodge 1975, from floating detritus and sediments in a subtropical mangrove island, Twin Cays, Belize, Central America are described from scanning electron micrographs. Differences in the following characters of surface micromorphology separated the species: ornamentation of thecal plates (shape, size, and number of valve pores and areolae) and the architecture of the periflagellar area and intercalary band.
LIFE HISTORY AND TAXONOMY OF RHIZOOCHROMONAS ENDOLORICATA GEN. ET SP. NOV., A NEW FRESHWATER CHRYSOPHYTE INHABITING DINOBRYON LORICAE1
Authors: Nicholls Kenneth H.
Published: October 2004

The life cycle of a previously undescribed chrysophyte, assigned to the new genus Rhizoochromonas, is described. It includes a small motile stage with heterokont flagellation which invades a Dinobryon lorica. Reproduction by cell division of the nearly spherical rhizopodial vegetative stage frequently leads to expulsion of the host protoplast through overcrowding of the lorica. Endogenous cysts (stomatocysts) are also formed within the Dinobryon lorica. The new family, Brehmiellaceae, is established to accommodate pseudopodial/rhizopodial chrysophytes with heterokont flagellation in the motile stage. Rhizoochromonas endoloricata gen. et sp. nov. has been found at two widely separated softwater locations in Ontario, and at one it constituted a major component of the planktonic flora during the autumns of six successive years.
BATRACHOSPERMUM HETEROCORTICUM SP. NOV. AND POLYSIPHONIA SUBTILISSIMA (RHODOPHYTA) FROM FLORIDA SPRING‐FED STREAMS1
Authors: Shealth Robert G. , Cole Kathleen M.
Published: October 2004

Polysiphonia subtilissima Mont. Is reported for the first time from a freshwater environment. The presence of four pericentral cells, subdichotomous branching, apical trichoblasts and rhizoids arising from pericentral cells combined with a lack of cortication and reproductive cells is consistent with marine populations of this species. The range of filament length is 1.4–4.7 cm. Branch diameters are 38–76 μm and pericentral cell lengths are 58–125 μm. Batrachospermum heterocorticum sp. nov. is distinguished primarily by a developmental change in cortical filaments from typical cylindrical cells (5.0–7.9 μm diam in initial stages to enlarged, elliptical cells (12.9–24.1 μm diam) in mature axes. Another unique feature of this species is carpogonia with cylindrical, pedicellate trichogynes on stringht carpogonial branches in mid to outer portions of lateral whorls. Other characteristics of B. heterocorticum include the following: olive‐green color, 2–6 cm length, dichotomous to trichotomous fascicles in 4–7 tiers, 385–647 μm whorl diameters, 109–198 μm carpospore diameters and relatively small “chantransia” filaments.
INFLUENCE OF DESICCATION ON THE MECHANICAL PROPERTIES OFIRIDAEA CORDATA(RHODOPHYTA)1
Authors: Kraemer George P.
Published: October 2004

The influence of desiccation on the mechanical properties of the intertidal macroalgaIridaea cordata(Turner) Bory (Rhodophyta) was investigated over a range of water losses (0–83%) that bracketed in situ levels (26–67%). The tissue modulus (stiffness) remained constant for water losses up to about 70%, but increased sharply with losses between 70–83%. Tissue strength of desiccated samples did not fall below the range measured for undesiccated samples. There was a significant increase in breaking strain up to water losses of about 50%, after which breaking strain decreased. The relationship between toughness and desiccation resembled that for breaking strain. Overall, the mechanical properties of Iridaea cordata did not deteriorate when desiccated to levels consistent with those observed in the field.
EFFECT OF SODIUM AND NITRATE ON GROWTH OF ANABAENA FLOS‐AQUAE (CYANOPHYTA)1
Authors: Oleson Diane J. , Makarewicz Joseph C.
Published: October 2004

The growth response of a nitrogen fixing cyanobacterium, Anabaena flos‐aquae (Lyng) Bréb., to sodium and nitrate was examined in batch culture under controlled laboratory conditions. Sodium (range 0‐12 mg Na+· L‐1) enhanced growth of the cyanobacterium under nitrate‐sufficient (5.7 mg NO3‐N · L‐1) but not nitrate‐limited (0.49 mg NO3‐ N · L‐1) conditions. The magnitude of the growth response was related to the nutritional history of the culture. No significant effect of sodium on nitrate utilization was observed. The increase in ambient sodium levels in many lakes may provide a competitive advantage to cyanobacteria.
SETTLEMENT AND SURVIVAL OFPOLYSIPHONIA LANOSA(CERAMIALES) SPORES ONASCOPHYLLUM NODOSUMANDFUCUS VESICULOSUS(FUCALES)1
Authors: Pearson Gareth A. , Evans Len V.
Published: October 2004

The settlement patterns of spores ofPolysiphonia lanosa(L.) Tandy onAscophyllum nodosum(L.) Le Jolis andFucus vesiculosusL. were studied using a flow tank. Settlement sites were defined as ‘sheltered’ or ‘exposed.’ Surface area calculations revealed non‐random settlement onA. nodosum, with higher than expected spore frequencies on the thallus and lateral pits and lower than expected frequencies on the vesicles. Settlement ofF. vesiculosuswas random and significantly lower than onA. nodosum.

On the shore, survival of sporelings from September (post‐sporulation) to May (pre‐sporulation) was highly non‐random on both basiphytes. OnA. nodosum, lateral pits ('sheltered') showed the highest survival frequency. Here the proportion of surviving sporelings increased over the study period, whereas the proportion on open thallus area ('exposed') decreased. OnF. vesiculosusalso preferential survival occurred on ‘sheltered’ sites such as vesicle/thallus interfaces and wounds. Between September and May, allP. lanosasporelings were lost from ‘exposed’ areas (thallus surface and vesicles). Overall, frequencies of surviving sporelings were much greater onA. nodosumthan onF. vesiculosus.These results are discussed with reference to basiphyte morphology, epiphyte removal mechanisms and the survival stratagy ofP. lanosa.
PRODUCTION AND NUTRIENT ACCUMULATION BY PERIPHYTON IN A WASTEWATER TREATMENT FACILITY1
Authors: Davis Laurie S. , Hoffmann James P. , Cook Philip W.
Published: October 2004

Five growth experiments were conducted over a 15‐month period to quantify biomass, seasonal growth rates, and production of a periphyton community in the secondary clarifier of a wastewater treatment plant. A maximum periphyton biomass of 130 g·m−2 (ash‐free dry weight) was achieved during fall. Growth rates of approximately 0.23·d−1 (from chlorophyll a) were observed during spring, summer and fall. Winter values were also high (0.20·d−1). Maximum production was approximately 22 g·m−2·d−1 during spring. Periphyton phosphorus and nitrogen content was variable ranging from 0.4–2.4 and 4.4–15.1%, respectively. Estimated maximum removal rates of both nutrients were high (up to ∼ 160 mg P·m−2·d−1 and ∼ 1900 mg N·m−2·d−1). High productivity and nutrient removal rates in this lotic hypereutrophic ecosystem may warrant further investigation of periphyton as a tertiary biological wastewater treatment in cold climates.
EFFECTS OF SUBSTRATE RELIEF ON THE DISTRIBUTION OF PERIPHYTON IN LABORATORY STREAMS, I. HYDROLOGY1
Authors: DeNicola Dean M. , McIntire C. David
Published: October 2004

We examined the hypothesis that the heterogeneity of epilithic algal assemblages in streams may be partly a result of hydrologic differences created when water flows over a rough substrate. A 32‐day experiment was conducted in laboratory streams that contained either 22.5 × 22.5 × 4 cm or 7.5 × 22.5 × 4 cm tile blocks. Free water velocities in the streams overaged 28 cm·s−1. Hydrologic parameters and algal assemblages associated with surfaces on top of blocks and with recessed surfaces between blocks were compared to corresponding surfaces in streams with of relief. In streams with blocks, shear velocities averaged 1.7 cm·s−1 on the top of blocks and 0.8 cm·s−1 in the recessed areas. Shear velocity at corresponding surfaces in the control (no relief) streams averaged 1.9 cm·s−1 and exhibited little variation. The hydrologic differences created by the larger blocks significantly affected the distribution of algal biomass, with recessed areas having an average of 2.6 g·m−2 AFDW more biomass than surfaces on the top of blocks. Differences in shear velocities and biomass accumulation between top and recessed areas for the smaller blocks were less than for large blocks. Successional changes on all substrates were similar with the exception that recessed surfaces had a significantly greater abundance of the filamentous chlorophyte Stigeoclonium tenue (Ag.) Kütz after day 16. The results suggest that in cobble riffle areas of natural streams, the interaction between current flow and substrate relief has the potential to create patches of algae which are different in biomass and taxonomic composition.
EFFECTS OF SUBSTRATE RELIEF ON THE DISTRIBUTION OF PERIPHYTON IN LABORATORY STREAMS. II. INTERACTIONS WITH IRRADIANCE1
Authors: DeNicola Dean M. , McIntire David
Published: October 2004

Laboratory streams were used in a 42‐day experiment designed to investigate how the spatial and temporal distribution of lotic periphyton created by current flow over cobble‐size substrates is a affected by irradiance. The streams contained 22.5 × 22.5 × 4 cm substrate blocks and were exposed to either 385, 90 or 20 μE·m−2·s−1. We monitored periphyton succession in fast current regimes on top of blocks and in slower current regimes on surfaces recessed between blocks.

The absolute differences in AFDW algal biomass between top and recessed substrates were significantly affected by irradiance and time. At the end of the experiment, biomass in streams exposed to 385 μE·m−2·s−1. was approximately 2 and 8 times greater than in streams exposed to 90 and 20 μE·m−2·s−1, respectively. Differences in biomass were greater between irradiance levels than between top and recessed substrates within an irradiance level. Irradiance also had a greater effect than current regime on the taxonomic composition of assemblages.Oscillatoria agardhiiGomont andNavicula minimaGrun. characterized assemblages at 20 μE·m−2·s−1, whereasFragilaria vaucheriae(Kütz.),Nitzschia oregonaSov.,Navicula arvensisHust. andStigeoclonium tenue(Ag.) Kütz. were more abundant at the two higher irradiances. Detrended correspondence analysis indicated that the rate of succession was relatively high for assemblages at high irradiance and in the slow current regimes between blocks. The results suggested that in natural streams, periphyton patches produced by large differences in irradiance should have a greater effect on periphyton heterogeneity than substrate‐induced patches. Moreover, the heterogeneity of algal patches produced by hydrologic differences over a substrate is constrained by irradiance level.
PIGMENT COMPOSITION OF THE SCALY GREEN FLAGELLATE MESOSTIGMA VIRIDE (MICROMONADOPHYCEAE) IS SIMILAR TO THAT OF THE SIPHONOUS GREEN ALGA BRYOPIS PLUMOSA (ULVOPHYCEAE)1
Authors: Fawley Marvin W. , Lee Connie M.
Published: October 2004

Pigments were isolated from Mesostigma viride Lauterborn by reversed‐phase high‐performance liquid chromatography and compared to standards from Chlamydomonas reinhardtii Dang. and Bryopsis plumose (Huds.) Ag. M. viride possesses chlorophylls a and b, α and β‐carotenes, and the xanthophylls siphonaxanthis, siphonein, neoxanthin, violaxanthin and echinenone. In addition, three unidentified xanthophylla were detected. Neither lutein nor zeaxanthin were detected. The pigment composition of M. viride was similar to that of B. plumosa which had chlorophylls a and b, ɛ‐ and α‐carotenes, siphonaxanthin, siphonein, neoxanthin, violaxanthin, and two of the unidentified xanthophylls found in M. viride. The similarities in the pigments of Mesostigma and Bryopsis and other characters suggest that Mesostigma may be related to a flagellate ancestor of the Ulvophyceae.
HETEROTROPHIC GROWTH OFULVA LACTUCA(CHLOROPHYCEAE)1
Authors: Markager Stiig , Sand‐Jensen Kaj
Published: October 2004

The effect of external glucose (51 mM) and acetate (13 mM) on growth and photosynthetic capacity ofUlva lactucaL. was tested in laboratory cultures over 41 days in the dark and in dim light (0.9 μmol photons·m−2·s−1) at 7–8° C. Glucose and acetate had a significant positive effect on growth rate, chlorophyll content, and quantum yield for discs grown in the dark and in dim light. The carbon gain from heterotrophic uptake was low and only allowedU. lactucato maintain a specific uptake was low and only allowedU. lactucato maintain a specific growth rate of 0.005 day−1compared to 0.06–0.1 day−1at higher light intensities. However, plants with added organic substrate maintained a normal chlorophyll content and were able to photosynthesize whereas control plants lost pigmentation and photosynthetic capability after 41 days in both dim light and darkness, probably because of disorganization of the photosynthetic apparatus. This suggest that the ecological significance of heterotrophic uptake is to allowU. lactucato survive during prolonged low light conditions with an intact photosynthetic apparatus.
EXTRACTION, ASSAY AND SOME PROPERTIES OF FLORIDOSIDE PHOSPHATE SYNTHASE FROM PORPHYRA PERFORATA (RHODOPHYTA)1
Authors: Meng Jianxin , Srivastava Lalit M.
Published: October 2004

A suitable method for extraction of floridoside phosphate synthase (FPS, UDP‐galactose: sn‐3‐glycerol phosphate: 1→2′α‐D‐galactosyl transferase)from Porphyra perforata J. Ag. was developed. Two assay methods for enzyme activity were utilized, one measuring the amount of floridoside formed by using gas‐liquid chromatography, the other measuring the sn‐3‐glycerol phosphate‐dependent formation of UDP; both assays gave similar results. FPS is a soluble protein, and FPS activity in the extract as determined by the amount of product formed in vitro compared well with the in vivo rate of floridoside synthesis (4–7 μMmol product formed·h−1·g−1 fresh wt). The rate of product formation in vitro was linear up to 45 min and proportional to protein concentration in the assay mixture. The temperature optimum was 30–35° C. FPS was active over a range of pH values from 7.0–8.5. It was stable in concentrated solutions in the presence of 0.3 M ammonium sulfate, but activity was lost in diluted solution (protein concentration below 0.2 mg·mL−1) or below 0.2 M ion strength. The data suggest that FPS may be an oligomeric protein which occurs free in the cytoplasm or loosely bound to a membrane. It may also be a regulatory protein controlling the overall rate of synthesis of floridoside in vivo.
SEPERATION OF MALLOMONAS DUERRSCHMIDTIAE SP. NOV. FROM M. CRASSISQUAMA AND M. PSEUDOCORONATA: IMPLICATIONS FOR PALEOLIMNOLOGICAL RESEARCH1
Authors: Siver Peter A. , Hamer Josephine S. , Kling Hedy
Published: October 2004

A new species, Mallomonas duerrschmidtiae, with characteristics common to both Mallomonas crassisquama (Asmund) Fott and Mallomonas pseudocoronata Prescott, is described from acidic lakes low in specific conductance and total phosphorus concentration. Characteristics of scales, bristles and spines serve to separate the three taxa. The length and area of scales of M. duerrschmidtiae are significantly larger than those of M. crassisquama but smaller than those of M. pseudocoronata. Although the anterior submarginal ribs of scales of M. duerrschmidtiae may become extended to form short wings, the scales lack the large forward projecting anterior wings characteristic of scales of M. pseudocoronata. Features of the dome and junction between the arms of the V‐rib and anterior submarginal ribs also serve to distinguish between the three species. Cells of M. duerrschmidtiae also possess long, smooth and thick spines on their posterior scales and lack helmet bristles. M. duerrschmidtiae has different maxima along pH, temperature, specific conductance, total phosphorus and seasonal gradients than either M. crassisquama or M. pseudocoronata. Discriminant analysis, based on nine morphological characters, was used to successfully classify body scales of the three species. The importance of M. duerrschmidtiae as a bioindicator in future lake monitoring and paleolimnological inference studies is discussed.
LEPIDODINIUM VIRIDE GEN. ET SP. NOV. (GYMNODINAIALES, DINOPHYTA), A GREEN DINOFLAGELLATE WITH A CHLOROPHYLL A‐ AND B‐CONTAINING ENDOSYMBIONT1,2
Authors: Watanabe Makoto M. , Suda Shoichiro , Inouya Isao , Sawaguchi Tomohiro , Chihara Mitsuo
Published: October 2004

A further description of the green dinoflagellate, strain Y‐100, with a chlorophyll a‐ and b‐containing endosymbiont is given with special emphasis on the morphology of the host cell. The host dinoflagellate cell is unarmored and has a gymnodinoid overall appearance. The theca or amphiesma basically consists of the outer membrane and flattened thecal vesicles in which no thecal plates are developed. Unusual hand basket‐shaped scales cover the entire cell surface together with a layer of mucilaginous material. These findings suggest that the organism is a new member of the Gymnodiniaceae (Gymnodiniales). We propose the name Lepidodinium viride gen. et sp. nov. The ultrasturcture of the host cell is typical of the dinoflagellates; however, the organism has 1) an unusual cytoplasmic projection that may be a homologue of the peduncle, 2) a single membrane‐bounded body containing membranous sheets, closely situated next to the endosymbiont, and 3) an electron opaque network‐forming appendage surrounding the transverse flagellum. Name of these features have been found in other dinoflagellates.
SELECTIVE CONDITIONS AND ISOLATION OF MUTANTS IN SALT‐TOLERANT, LIPID‐PRODUCING MICROALGAE1
Authors: Galloway Ruth E.
Published: October 2004

Suitable conditions for the isolation and selection of generic markers were determined by testing the growth of nine axenic strains of lipid‐producing algae (representatives of Bacillariophyceae, Eustigmatophyceae, and Chlorophyceae) under a variety of conditions. Mixotrophic, heterotrophic, or anaerobic growth on twenty different carbon compounds was determined. In addition, ten different carbon compounds was determined. In addition, ten different nitrogen‐containing compounds were supplied as the sole nitrogen source to ascertain which of these could be utilized. Resistances to various antibiotics and herbicides were also assessed.

The algae utilized a variety of compounds as their sole nitrogen source, and some species also grew heterotrophically or mixotrophically on a variety of carbon compounds. This suggests that the algae are not only able to transport these compounds into the cell but that the biochemical pathways necessary for their utilization are present and could be targeted for mutagenesis. Anaerobic growth was not possible on any of the photosystem II inhibitors diuron and atrazine and the 70S ribosome inhibitors erythromycin and streptomycin. However, the diatoms were insensitive to spectinomycin and sulfometuron methyl. Information about drug sensitivities permitted the selection of drug resistant mutants. Mutagenized cultures produced colonies when plated on media containing drug concentrations that were growth‐inhibiting for wild‐type cultures. Mutations were recovered in Monoraphidium, Nannochloropsis and Navicula species.