Showing papers in "Phycologia in 1982"
TL;DR: Populations of Sargassum cymosum from Ubatuba (S.P., Brazil), exposed to various degrees of wave intensity, are compared and the differences found between the populations from the extreme exposure are significant.
Abstract: Populations of Sargassum cymosum from Ubatuba (S.P., Brazil), exposed to various degrees of wave intensity, are compared. The differences found between the populations from the extreme exposure ind...
72 citations
68 citations
TL;DR: Growth of various species of macro-algae and diatoms was measured in culture in a range of concentrations of germanium dioxide to inhibit growth of Laminaria saccharina.
Abstract: Growth of various species of macro-algae and diatoms was measured in culture in a range of concentrations of germanium dioxide. Growth of Laminaria saccharina was inhibited measurably at concentrations above 0.22 mg GeO2 l−1 and very markedly inhibited above 1.1 mg GeO2 l−1. Fucus spiralis was measurably inhibited at concentrations above 0.22 mg GeO2 l−1, as was Ulva lactuca at concentrations above 2.2 mg GeO2 l−1. The Rhodophyta tested (Polysiphonia urceolata, Porphyra umbilicalis, Chondrus crispus) showed no inhibition by GeO2. Most diatoms tested were strongly inhibited by concentrations of 0.134 mg GeO2 l−1. It is suggested that the majority of diatoms can be controlled without inhibiting the growth of most cultures of species of Phaeophyta or Chlorophyta by short-term application of GeO2 in concentrations of 0.045–0.179 mg GeO2 l−1 (0.01–0.04 ml sat. GeO2 soln. l−1) instead of the much higher concentrations previously suggested.
67 citations
TL;DR: Bostrychia radicans Mont., Caloglossa leprieurii (Mont.) J. Ag.
Abstract: Bostrychia radicans Mont., Caloglossa leprieurii (Mont.) J. Ag. and Polysiphonia subtilissima Mont., were widely distributed in the Mullica River estuary, with Bostrychia more abundant near the mouth, and Caloglossa and Polysiphonia towards the head of the estuary. All three species grew during the warmer months of the year and were apparently absent in winter. Bostrychia and Caloglossa had ‘Polysiphonia’ -type life histories in culture, despite the infrequent occurrence of male plants in the field. Polysiphonia could not be induced to undergo sexual reproduction in culture, which corresponded with the rare occurrence of sexual reproductive organs in nature. The growth of sporelings and adults in culture in the laboratory in crossed gradients of salinity and temperature was correlated with their distribution in the field. The salinity optimum of Bostrychia was higher than that of Caloglossa and Polysiphonia, although all three species were euryhaline. The seasonal occurrence of the three species ...
60 citations
TL;DR: The morphology and fine structure of six species of the monoraphid diatom genus Cocconeis Ehr have been investigated and all taxa show a tendency towards irregu...
Abstract: The morphology and fine structure of six species of the monoraphid diatom genus Cocconeis Ehr. have been investigated. The raphid valve is concave and thinner than the convex araphid valve. The vel...
48 citations
TL;DR: Cell size and shape, nucleus shape and position, cingulum arrangement, the pellicular layer, chain formation, apical markings, toxicity and possibly cyst morphology indicate close affinities with members of the thecate genus Protogonyaulax Taylor.
Abstract: Samples of the unarmoured dinoflagellate Gymnodinium catenatum Graham, collected from the plankton during an outbreak of paralytic shellfish-poisoning, were examined with light and electron microscopy. No thecal plates were seen. Instead, a pellicular layer surrounded the cells. Cell size and shape, nucleus shape and position, cingulum arrangement, the pellicular layer, chain formation, apical markings, toxicity and possibly cyst morphology indicate close affinities with members of the thecate genus Protogonyaulax Taylor.
47 citations
TL;DR: Details of the scales, including a new type not previously seen in the genus, a ring of lipid bodies in the collar surrounding the pit, cell size and shape are described.
Abstract: A prasinophycean flagellate blooming in Antarctic sea ice is reported for the first time. Pyramimonas gelidicola sp. nov., isolated from Prydz Bay, East Antarctica, is described from the light and ...
41 citations
TL;DR: The atypical free-living form of Pilayella appears to result from ball fragmentation and subsequent regeneration solely by vegetative cell division, and has a peak summer-time abundance of hundreds of tonnes (live weight).
Abstract: A previously unreported free-living form of Pilayella is described. During all months of the year, drifting clouds of this plant may carpet up to half of the sandy bottom and beaches of Nahant Bay, a 15 km2 rectangular embayment on the north coast of Massachusetts. Four features distinguish the atypical free-living form from the typical attached form of this species: (1) a ball shape and a concomitant general lack of polarity in the development of the central axes; (2) a polystichous condition present throughout much of the central axes; (3) a dearth of reproductive organs; and (4) a peak summer-time abundance of hundreds of tonnes (live weight). Plant reproduction and growth appear to result from ball fragmentation and subsequent regeneration solely by vegetative cell division. Fragmentation results from seasonal senescence of the filamentous axes and from infection by the marine fungus Eurychasma dicksonii. The Pilayella drift community is characterized by its virtual monospecificity by weight,...
TL;DR: The ultrastructure of the filamentous blue-green algal endosymbiont Oscillatoria spongeliae studied in detail, suggesting that their metabolism must be simil...
Abstract: A number of collections of the tropical sponge Dysidea herbacea (Dictyoceratida, Dysideidae) have been made on the Great Barrier Reef, Australia and the ultrastructure of the filamentous blue-green algal endosymbiont Oscillatoria spongeliae studied in detail. Oscillatoria spongeliae occurs in the mesohyl ofthe ectosome in close association with sponge archaeocytes. Digestion of the algae occurs only rarely, but algae in various stages of digestion have been observed within archaeocytes. The sheathless filaments of O. spongeliae are from four to twenty cells long. Some of the cells of the filament are specialized as necridia, and breakage of filaments along necridial cell walls has been observed. The thylakoids are usually arranged more or less at right angles to the longitudinal cell wall and are evenly spaced around the cell. The algal cells have a typical blue-green algal cell wall and contain various inclusion bodies characteristic of these algae, suggesting that their metabolism must be simil...
TL;DR: A comparative study of reproduction in the type species of Mastophora and Lithoporella has revealed that differences associated with tetrasporangial conceptacle development and structure provide a reliable basis upon which to delineate the two genera.
Abstract: A comparative study of the type species of Mastophora and Lithoporella (Corallinaceae, Rhodophyta) indicates that the two genera cannot be delineated reliably using attributes of the vegetative tha...
TL;DR: Seasonality, survivorship and individual growth patterns of Pelagophycus porra were studied, as 86% of the cohort disappeared within 12 months and terminal stipe length was highly variable, both within and between year classes.
Abstract: Seasonality, survivorship and individual growth patterns of Pelagophycus porra were studied. Bi-weekly measurements were obtained from a cohort of seventy plants growing at 17–21 m depth off Santa Catalina Island, California, beginning with the undivided lamina stage and continuing until plant death or loss. Comparisons were made with a group of thirty-two co-occurring adults. Most sporophytes first appeared from May to July. Pelagophycus is an annual, as 86% of the cohort disappeared within 12 months. Stipe elongation rates of the cohorts displayed a sigmoid growth pattern with a maximum mean rate of 0.7 cm/d from July through November. Terminal stipe length was highly variable, both within and between year classes. The zone of greatest blade elongation was 10–30 cm from the blade–stipule junction. Blade growth ranged from 5.1–6.5 cm/d during July and August, and 2.7–3.2 cm/d from January through March. Rates of stipe elongation and blade growth in naturally occurring Pelagophycus × Macrocystis ...
TL;DR: The data indicate that carotenoid epoxides are probably more common in the Rhodophyceae than is generally indicated, and phylogenetic schemes based on pigment composition must be modified accordingly to accommodate these compounds.
Abstract: It has been generally accepted that the carotenoids of the rhodophycean algae are α-carotene, β-carotene, lutein, and zeaxanthin. However, one report on a species of Gracilaria indicated that antheraxanthin, an epoxide, was the major carotenoid. We have confirmed this report and have examined twenty-one other samples (mostly unialgal cultures, some field material) representing at least another eight species of Gracilaria. All of these samples contained antheraxanthin, and many also had the diepoxide, violaxanthin. This is the first report of the latter compound for this genus. Our data indicate that carotenoid epoxides are probably more common in the Rhodophyceae than is generally indicated, and phylogenetic schemes based on pigment composition must be modified accordingly to accommodate these compounds in the Rhodophyceae.
TL;DR: It is estimated that Prochloron cells, freshly isolated from colonies of their ascidian host, Lissoclinum patella, can fix CO2 photosynthetically at rates exceeding 120 mM g−1 chlorophyll h−1 in longer fixation periods proportionately more insoluble material was formed.
Abstract: It is estimated that Prochloron cells, freshly isolated from colonies of their ascidian host, Lissoclinum patella, can fix CO2 photosynthetically at rates exceeding 120 mM g−1 chlorophyll h−1 In longer fixation periods (up to 1 h) proportionately more insoluble material was formed. Of the products soluble in aqueous alcohol, more than 50% consisted of amino acids and about 20% of acids in the TCA cycle, additionally including glycolate. Free monosaccharides or disaccharides are lacking. The lipid products included non-polar lipids (24%), diglycerides (37% monogalactosyl) and phosphatidyl glycerol (11%). Oligoglucans composed more than 95% of the residual insoluble fraction. The results are discussed from a chemotaxonomic point of view.
TL;DR: Some non-heterotrophic phytoplankters appear to be capable of photoassimilating exogenous dissolved organic carbon and it has been suggested that they may utilize such material as a raw material for photosynthesis.
Abstract: Some non-heterotrophic phytoplankters appear to be capable of photoassimilating exogenous dissolved organic carbon and it has been suggested that these phytoplankters may utilize such material as a...
TL;DR: Algae living in snow banks that persist into the summer in the Snowy Mountains of Australia have been investigated and those identified as Chlamydomonas nivalis (Bau.) Wille and Chlamies bolyaiana Kol colour the snow bright-red.
Abstract: Algae living in snow banks that persist into the summer in the Snowy Mountains of Australia have been investigated. Those identified as Chlamydomonas nivalis (Bau.) Wille and Chlamydomonas bolyaian...
TL;DR: Re-investigation of R. elegans from California in culture indicates that structures on tetrasporangial crusts previously interpreted as ‘hair cells’ are carpogonia, and this life history is the most reduced of all those known in sexually reproducing red algae.
Abstract: Previous studies of field collected and cultured plants of Rhodophysema from different localities have demonstrated the existence of tetrasporangial and male plants, whereas female plants were apparently absent. Re-investigation of R. elegans from California in culture indicates that structures on tetrasporangial crusts previously interpreted as ‘hair cells’ are carpogonia. The fertilized carpogonium (zygote) divides into a stalk cell (tetrasporangial mother cell) and a tetrasporangium. The contents of the sporangium divides to produce four tetraspores, whereas the stalk cell produces successive tetrasporangia. A carposporophyte is lacking. The vegetative tissue of the crust is not sporophytic, as previously supposed, but is gametophytic, with spermatia and carpogonia produced on the same crust. This life history is the most reduced of all those known in sexually reproducing red algae. The position of the carpogonium—terminal on a vegetative filament rather than on a specialized branch—and the pr...
TL;DR: The life cycle of Ascoseira is interpreted according to a fucalean scheme in which a free-living sporophyte bears a cytological gametophyte and gives rise to plants morphologically similar to young plants collected in the field.
Abstract: Ascoseira mirabilis, a large brown alga endemic to the Antarctic Peninsula and the Scotia Arc, has been assigned with uncertainty to the Fucales or to the monotypic order Ascoseirales. Its reproductive cells, described herein from living material, are biflagellate swarmers which in culture germinate without fusion. Chains of sporangia are produced in conceptacles. The original nucleus of each sporangium initiates a series of three divisions, and the resulting eight nuclei are walled off simultaneously. The nucleus in each compartment divides once. One daughter nucleus is segregated by a wall and does not develop further; the other is incorporated into a swarmer which is released after the sporangium is discharged from the conceptacle. Settled swarmers give rise to plants morphologically similar to young plants collected in the field. We interpret the life cycle of Ascoseira according to a fucalean scheme in which a free-living sporophyte bears a cytological gametophyte. The last nuclear division ...
TL;DR: The biomass yield of Peridinium was found to be more sensitive to a decrease in levels in intracellular acid insoluble P than were those of Pediastrum and Cosmarium.
Abstract: In a comparative study in batch cultures, the biomass yield of Peridinium cinctum fa. westii was found to decrease gradually as a result of gradual phosphate depletion, whereas a significant effect on the biomass yield of Pediastrum and Cosmarium grown in identical conditions was observed only at lower P0 (0.6 μM and 0.2 μM). In conditions of high phosphate availability, all three species accumulated phosphorus in an intracellular storage pool. Orthophosphate in the hot water extract fraction was shown to be a poor measure of the intracellular phosphorus storage. The 6% cold trichloracetic acid (TCA) insoluble phosphorus fraction contained the major storage pool of phosphorus in these algae. The level of this pool was found to be very sensitive to changes in ambient orthophosphate. The biomass yield of Peridinium was found to be more sensitive to a decrease in levels in intracellular acid insoluble P than were those of Pediastrum and Cosmarium. Results indicated that the alkaline phosphatase acti...
TL;DR: The morphology of three British species of the red algal genus Laurencia (Ceramiales, Rhodophyta) has been studied and shows many similar characters, and both are intermediate between the western Pacific species and Chondrophycus and the eastern Pacific species.
Abstract: The morphology of three British species of the red algal genus Laurencia (Ceramiales, Rhodophyta) has been studied. Laurencia obtusa (Hudson) Lamouroux, the type species of the genus, fits well into the traditional circumscription of subgenus Laurencia. Laurencia hybrida (De Candolle) Lenormand ex Duby and L. pinnatifida (Hudson) Lamouroux show many similar characters, and both are intermediate between the western Pacific species (subgenera Laurencia and Chondrophycus) and the eastern Pacific species (Spectabilis group) of the genus.
TL;DR: Spermatozoids in Laminaria digitata exhibit fine-structural details typical for male brown algal gametes, except for the presence of well-developed chloroplasts and lack of an eye-spot, which are involved in the explosive bursting of the antheridia.
Abstract: Spermatozoids in Laminaria digitata exhibit fine-structural details typical for male brown algal gametes, except for the presence of well-developed chloroplasts and lack of an eye-spot. The most conspicuous features of mature antheridia are a specialized swelling of the cell wall (cap) and large amounts of mucilage surrounding the spermatozoid. Both components are involved in the explosive bursting of the antheridia, which is triggered by a hormonal factor.
TL;DR: Okamura et al. as discussed by the authors performed an ultrastructural examination of the trichothallic meristem in Cutleria cylindrica and revealed that centrioles and rudimentary asters appear to be present throughout the cell cycle.
Abstract: Abstract Ultrastructural examination of the trichothallic meristem in Cutleria cylindrica Okamura reveals that centrioles and rudimentary asters appear to be present throughout the cell cycle. Centriole duplication and migration to opposite nuclear po es are the first visible signs of prophase. Numerous extranuclear microtubules are found at the nuclear poles and around the nuclear envelope at prophase. The nucleolus is not visible at late prophase, and the chromatin appears more condensed. The nuclear envelope remains intact until meta-phase when prominent polar fenestrations become evident. The envelope consists of vesicles and cisternae by the end of metaphase, but the nuclear outline remains evident. Few extranuclear microtubules are visible during metaphase. The spindle develops within the remnants of the nuclear envelope. Well-defined kinetochores were never observed. The chromosome-to-pole distance seems to decrease during anaphase, but further confirmation of this is necessary. The pole-to-pole di...
TL;DR: Chaetomorpha linum and C. atrovirens appear to be distinct species based upon their morphological discontinuity and low degree of electrophoretic similarity.
Abstract: The taxonomic separation of Chaetomorpha linum and Chaetomorpha atrovirens was evaluated by morphological analyses of field and herbarium specimens, and through starch gel electrophoretic analysis of genetic similarities. Chaetomorpha aerea and Chaetomorpha melagonium were also assessed electrophoretically and compared with the above species. C. linum and C. atrovirens appear to be distinct species based upon their morphological discontinuity and low degree of electrophoretic similarity. The two species are separable by their mean length/width ratios (LWR). C. linum has a mean LWR of less than 1.5 and filament widths of 150–450 μm, while C. atrovirens has a LWR in excess of 2.0 and filament widths of 200–400 μm. Electrophoretic information regarding the separation of C. linum and C. aerea is presented and possible phylogenetic relationships between C. linum, C. atrovirens, C. melagonium and C. aerea are discussed.
TL;DR: Sarcodiotheca furcata and S. dichotoma grow multiaxially with a single periaxial cell cut off from each succeeding axial cell in an orthostichous file, and the auxiliary cell complex is recognizable prior to diploidization.
Abstract: Sarcodiotheca furcata and S. dichotoma grow multiaxially with a single periaxial cell cut off from each succeeding axial cell in an orthostichous file. Branching of primary apices is dichotomous, apparently resulting from division of the apical cells into two equal initials, whereas lateral branches are formed adventitiously from surface cortical cells. The auxiliary cell complex, consisting of the auxiliary cell and surrounding darkly-staining inner cortical cells, is recognizable prior to diploidization. Typically, two unbranched and non-septate connecting filaments are formed from each fertilized carpogonium. Fusion of a connecting filament with an auxiliary cell stimulates development of the involucre. A gonimoblast initial is cut off from the auxiliary cell and divides forming a compact cluster of gonimoblast cells. In the first phase of carposporophyte development the gonimoblast radiates out and fusions occur between gonimoblast and vegetative cells producing a central placenta. In the sec...