bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE ATLANTIC SPECIES OF SOLIERIA (GIGARTINALES, RHODOPHYTA): THEIR MORPHOLOGY, DISTRIBUTION AND AFFINITIES1
Authors: Gabrielson Paul W. , Hommersand Max H. 
Published: August 2007

ABSTRACT Solieria chordalis (C. Agardh) J. Agardh and S. tenera (J. Agardh) Wynne et Taylor exhibit multiaxial growth from a cluster of four to eight obconical apical cells. A single periaxial cell is cut off from each axial cell and successive periaxial cells are rotated 120° in a zig‐zag pattern along each axial filament. Periaxial cells produce branched, laterally diverging filaments which form the cortex. The medulla is composed of axial cells, elongate cells of lateral filaments, stretched interconnecting cells, and secondary rhizoids. The two species are nonprocarpic. Carpogonial branches are 3‐celled, inwardly directed, with a reflexed trichogyne. The auxiliary cell together with associated darkly‐staining inner cortical cells form an association, the auxiliary cell complex, that is recognizable prior to diploidization. A single, unbranched, non‐septate connecting filament issues from the fertilized carpogonium and fuses with the inner, lateral side of an auxiliary cell. Production of an involucre from surrounding vegetative cells is stimulated and a gonimoblast initial is cut off toward the interior of the thallus which divides to form a compact cluster of gonimoblast cells. A fusion cell is produced through fusion of inner gonimoblast cells with the auxiliary cell that, in turn, fuses progressively with cells of the lateral file bearing the auxiliary cell. Mature cystocarps have terminal carposporangia cut off from gonimoblast cells at the periphery of the fusion cell and are surrounded by an involucre with a distinct ostiole. Tetrasporangia are cut off laterally from surface cortical cells which then cut off one or two additional derivatives toward the outside.A lectotype is designated for Solieria chordalis, but the lectotypification of S. tenera is questioned. We conclude that Solieria is closely related to Rhabdonia and place the Rhabdoniaceae in synonomy with the Solieriaceae.
THE MORPHOLOGY OF AGARDHIELLA SUBULATA REPRESENTING THE AGARDHIELLEAE, A NEW TRIBE IN THE SOLIERIACEAE (GIGARTINALES, RHODOPHYTA)1
Authors: Gabrielson Paul W. , Hommersand Max H. 
Published: August 2007

ABSTRACT Agardhiella subulata (C. Agardh) Kraft et Wynne is a commonly collected erect, terete, alternately branched, fleshy red alga that is found both intertidally and subtidally in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico. A single periaxial cell is cut off from each succeeding axial cell in an orthostichous file. The supporting cells of carpogonial branches are homologous with auxiliary cells, being transformed from identical inner cortical cells. The auxiliary cell together with the three to four enlarged, darkly‐staining cortical cells pit‐connected to it form the auxiliary cell complex. Following fusion of a connecting filament to an auxiliary cell the diploid nucleus divides with one nucleus remaining near the point of fusion and the other migrating to the beaked portion of the auxiliary cell. Surrounding vegetative cells divide, forming files of cells that grow toward the auxiliary cell to form the involucre. Cells of the gonimoblast fuse with nearby cortical cells producing a placenta of vegetative and gonimoblast tissue. As the cystocarp matures the inner placental cells become vacuolate while at the periphery terminal and short, unbranched files of gonimoblast cells mature into carposporangia. Tetrasporangia are cut off laterally from surface cells and undergo basal elongation followed by lateral expansion before dividing zonately. A. subulata exhibits a combination of distinctive vegetative and reproductive features when compared with Solieria and thus serves as the type of a new tribe, the Agardhielleae, in the family Solieriaceae.
SIZE DEPENDENCE OF GROWTH RATE, RESPIRATORY ELECTRON TRANSPORT SYSTEM ACTIVITY, AND CHEMICAL COMPOSITION IN MARINE DIATOMS IN THE LABORATORY1
Authors: Blasco Dolors , Packard T. T. , Garfield Paula C. 
Published: August 2007

ABSTRACTThe dependence of growth, electron transport system activity and chemical composition on the size of diatoms was examined during the exponential phase of growth. The six different marine centric species compared ranged in volume from 7.7 μm3 to 62 × 105μm3. A size dependence was observed for growth, 14C uptake, respiration and the productivity index (14C/chl a). Although the size dependence of all parameters was similar, the results indicate that on a carbon basis, growth efficiency decreases with increasing size. The C/N and C/chl a ratios were not size dependent. The importance of the surface area to cell volume ratio, and the importance of carbon per unit volume in determining the observed size dependence are discussed.
REMOVAL OF ORGANIC AND INORGANIC MATTER FROM ANTARCTIC LAKES BY AERIAL ESCAPE OF BLUEGREEN ALGAL MATS1
Authors: Parker Bruce C. , Simmons George M. , Wharton Robert A. , Seaburg Kenneth G. , Love F. Gordon 
Published: August 2007

ABSTRACTField studies on three perennially ice‐covered Antarctic oasis lakes with little or no outflow disclosed a unique biological phenomenon. Benthic algal mats dominated by the prokaryotic Phormidium frigidum Fritsch and several pennate diatoms growing in shallower, more brightly illuminated areas beneath 4 to 5.5 m of ice accumulate and entrap bubbles of photosynthetically produced oxygen. Clumps of this gas‐filled mat tear loose from the gravelly substrate, lift off and float to the bottom of the lake ice. Some of these floating mat pieces become frozen into newly forming ice with the onset of winter. Through the combination of ablation of ice from the upper surface and the formation of new ice from below, algal mat pieces reach the upper lake surface in 5–10 years. Here, they are lyophilized by polar winds and dispersed in at least a partially viable state. The process of mat lift‐off and escape is important in removing nutrients and salts from these lakes and helps to perpetuate their oligotrophic state. Neutron activation and X‐ray dispersive analyses of elements in the algal mats along with other analyses, field observations, and calculations suggest that significant quantities of organic matter, select minerals and salts are lost from the lakes annually through this process whose magnitude has not been recognized previously.
HALIMEDA HUMMII SP. NOV., HALIMEDA CRYPTICA V. ACERIFOLIA VAR. NOV. (CAULERPALES, CHLOROPHYTA), AND ADDITIONAL RECORDS OF HALIMEDA SPECIES FROM: PUERTO RICO1
Authors: Ballantine David L. 
Published: August 2007

ABSTRACTA new species, Halimeda hummii, and a new variety of Halimeda cryptica Colinvaux and Graham both originally collected from the edge of the continental shelf on the southwest coast of Puerto Rico are newly described. The new species is irregular in its segment morphology and is the smallest species of Halimeda presently known. Halimeda cryptica var. acerifolia from deep water possesses distinctive segments resembling maple leaves. Halimeda copiosa Goreau and Graham and typical H. cryptica are also collected in deep water and are newly recorded from Puerto Rico.
EFFECTS OF LIGHT AND TEMPERATURE ON NET PHOTOSYNTHESIS AND DARK RESPIRATION OF GAMETOPHYTES AND EMBRYONIC SPOROPHYTES OF MACROCYSTIS PYRIFERA1
Authors: Fain Steven R. , Murray Steven N. 
Published: August 2007

ABSTRACTThe rates of net photosynthesis as a function of irradiance and temperature were determined for gametophytes and embryonic sporophytes of the kelp, Macrocystis pyrifera (L.) C. Ag. Gametophytes exhibited higher net photosynthetic rates based on oxygen and pH measurements than their derived embryonic sporophytes, but reached light saturation at comparable irradiance levels. The net photosynthesis of gametophytes reached a maximum of 66.4 mg O2 g dry wt−1 h−1 (86.5 mg CO2 g dry wt−1 h−1), a value approximately seven times the rate reported previously for the adult sporophyte blades. Gametophytes were light saturated at 70 μE m−2 s−1 and exhibited a significant decline in photosynthetic performance at irradiances 140 μE m−1 s−1. Embryonic sporophytes revealed a maximum photosynthetic capacity of 20.6 mg O2 g dry wt−1 h−1 (25.3 mg CO2 g dry wt−1 h−1), a rate about twice that reported for adult sporophyte blades. Embryonic sporophytes also became light saturated at 70 μE m−2 s−1, but unlike their parental gametophytes, failed to exhibit lesser photosynthetic rates at the highest irradiance levels studied; light compensation occurred at 2.8 μE m−2 s−1. Light‐saturated net photosynthetic rates of gametophytes and embryonic sporophytes varied significantly with temperature. Gametophytes exhibited maximal photosynthesis at 15° to 20° C, whereas embryonic sporophytes maintained comparable rates between 10° and 20° C. Both gametophytes and embryonic sporophytes declined in photosynthetic capacity at 30° C. Dark respiration of gametophytes was uniform from 10° to 25° C, but increased six‐fold at 30° C; the rates for embryonic sporophytes were comparable over the entire range of temperatures examined. The broader light and temperature tolerances of the embryonic sporophytes suggest that this stage in the life history of M. pyrifera is well suited for the subtidal benthic environment and for the conditions in the upper levels of the water column.
PEROXIDASE IN CAULERPA1
Authors: Menzel D. , Grant B. R. 
Published: August 2007

ABSTRACTA survey of 17 species of Caulerpa showed peroxidase activity to be widespread in this genus. The intracellular location of the activity varied in different species, but only in C. cliftoni Harvey was it associated with wound plugs. In eight species peroxidase activity was present in the branching points of the trabeculae and in 12 of the 17 species it was found in the cell wall or in the trabeculae adjacent to the cell wall. Peroxidase was isolated from one species, C. simpliciuscula C. Ag., and some of its properties examined. Two isoenzymes were present, both of them different from the peroxidase isolated from Batophora oerstedii J. Agardh and Cymopolia barbata L.
PHOSPHATE UPTAKE BY THE OCEANIC DINOFLAGELLATE PYROCYSTIS NOCTILUCA1
Authors: Rivkin Richard B. , Swift Elijah 
Published: August 2007

ABSTRACTPhosphate uptake by P‐replete and P‐depleted Pyrocystis noctiluca (Murray) Schütt grown at different ambient N:P ratios was multiphasic between 0.1 and 100 μM PO43‐. Within each of the kinetic phases, the saturated uptake rate (Vmax), but not the half saturation constant (Km) was affected by the cellular‐P status and light. Uptake rates in the dark were ca. 50% of that in the light and respiratory activity accounted for the observed basal uptake. The combination of multiphasic uptake, and the uncoupling of short term transient uptake from growth resulting in maximum specific uptake rates of 50 h−1 may help explain the abundance of P. noctiluca in oligotrophic regions.
DISTRIBUTION OF EDAPHIC DIATOMS IN A MISSISSIPPI SALT MARSH: A CANONICAL CORRELATION ANALYSIS1
Authors: Sullivan Michael J. 
Published: August 2007

ABSTRACTA canonical correlation analysis was performed to examine the degree to which edaphic diatom distribution in Graveline Bay Marsh, Mississippi could be related to environmental factors. It was possible to collapse the complex data base into two interpretable, orthogonal dimensions and to identify five distinct diatom communities. Diatom distribution on the marsh was primarily regulated by elevation and height of the overstory spermatophyte canopy. Although redundancy in the species data given the environmental data was relatively low (23% for the first two canonical variables), similar values were obtained for studies of benthic and planktonic diatoms in Yaquina Estuary, Oregon. The present study represents the first application of multivariate statistics to the study of salt marsh diatoms and demonstrates its usefulness in an environment where gradients are difficult to perceive.
STRUCTURE AND DEVELOPMENT OF THE CARPOSPOROPHYTE OF NEMALION HELMINTHOIDES (NEMALIONALES, RHODOPHYTA)1
Authors: Ramm‐Anderson Sue M. , Wetherbee Richard 
Published: August 2007

ABSTRACTFollowing fertilization, the carposporophyte of Nemalion helminthoides (Velley in With.) Batters differentiates into four distinct regions: the fusion cell, the sterile gonimoblast cells, the carposporangial mother cells and the carposporangia. The gonimoblast is formed by apically dividing, monopodial filaments of limited growth which may later become pseudodichotomous. Upon differentiation of a terminal carposporangium, a gonimoblast filament may continue to grow sympodially. A single carposporangial mother cell may produce carposporangia in several different directions as well as proliferate successive carposporangia within the sporangial walls that remain after carpospore liberation. As the carposporophyte matures, the gonimoblast initial, the stalk cell, the hypogynous and subhypogynous cells fuse. Except for the fusion cell, all cells of the carposporophyte show organelle polarity and contain a distally located, lobed chloroplast and proximal nucleus.
ASSESSING PHYSIOLOGICAL STRESS IN THALASSIOSIRA FLUVIATILIS (BACILLARIOPHYTA) AND DUNALIELLA TERTIOLECTA (CHLOROPHYTA) WITH DCMU‐ENHANCED FLUORESCENCE1
Authors: Sellner Kevin G. , Lyons Larry , Perry Elgin S. , Heimark Douglas B. 
Published: August 2007

ABSTRACTExponentially growing cultures of Thalassiosira fluviatilis Hustedt and Dunaliella tertiolecta Butcher were exposed to 4 min temperature shocks of 5° to 20°C above ambient (20°C). Photosynthetic carbon fixation, changes in in vivo fluorescence and fluorescence on the addition of the herbicide DCMU (3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea) were measured over the subsequent 24 h. The fluorescence ratio (R, DCMU‐enhanced fluorescence/in vivo fluorescence) paralleled changes in photosynthesis over this period; both were significantly reduced (P < 0.05) by temperature shocks of +15° and +20° C, but +5° and +10° C treatments had no inhibitory effect on either relative to the control. The instantaneous response obtained with the fluorescence ratio indicates that the technique might be applicable to routine bioassay procedures and thus replace the time consuming methods now used for the estimation of 14C‐incorporation and growth rates.
PHYSIOLOGICAL VARIATION AND ELECTROPHORETIC BANDING PATTERNS OF GENETICALLY DIFFERENT SEASONAL POPULATIONS OF SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)1
Authors: Gallagher Jane C. 
Published: August 2007

ABSTRACTClones of Skeletonema costatum (Grev.) Cl. isolated from Narragansett Bay, R.I., during different seasons were grouped according to their electrophoretic banding patterns. The growth rates, pg chlorophyll · cell−1, carbon uptake · cell−1· h−1, and carbon uptake · pg chl−1· h−1 were measured at 20°C, in a 14:10 h L:D cycle at 180 μE · m−2· s−1. Statistically significant sources of variation were found among groups of clones in growth rate, pg chl · cell−1, and carbon uptake · pg chl−1· h−1. It was concluded that there is a significant relationship between the physiological characteristics of clones isolated from populations in different seasons and patterns of genetic variation inferred from the electrophoretic studies. However, genetic diversity detected by banding patterns tends to underestimate the total genetic diversity in natural populations. The groups of clones most common in summer bloom populations had significantly higher growth rates, lower values of pg chl · cell−1, and higher rates of carbon uptake · pg chl−1· h−1 at 20°C than did the group of clones most common in winter bloom populations. However, differences among groups in these parameters at 20°C alone cannot account for the seasonal cycling of genetically variable populations of Skeletonema in Narragansett Bay. The range of growth rates among clones of this species is 0.1–5.0 divisions · d−1 under a single set of temperature and light conditions. Chlorophyll concentrations range from 0.2–1.7 pg chl · cell−1 and carbon uptake · pg chl−1· h−1 varies by a factor of 7 among clones. The range of physiological variation in this species means that it is difficult to use laboratory studies of single clones to analyze the responses of natural populations of Skeletonema.
STRUCTURE, LIFE HISTORY AND SYSTEMATICS OF RHOICOSPHENIA (BACILLARIOPHYTA). I. THE VEGETATIVE CELL OF RH. CURVATA1
Authors: Mann David G. 
Published: August 2007

ABSTRACT Rhoicosphenia Grun. has been placed by some authors in the monoraphid group with Achnanthes Bory and Cocconeis Ehrenb., and by others near Gomphonema Ehrenb. In order to clarify the systematic position of the genus, the morphology and anatomy of the vegetative cells of Rh. curvata (Kütz.) Grun. were investigated using light and electron microscopy. The structure and formation of the two types of valve are described, and the heterovalvy shown to be of a different type from that of the monoraphids; on the basis of raphe, valve and girdle structure a close relationship between these and Rhoicosphenia is unlikely. Rhoicosphenia shows many resemblances to Gomphonema but the types of pore occlusion present, coupled with apparently slight differences in the mucilage‐secreting structures and the girdle, suggest that classification in the same family is unwise. The cryptic asymmetry of the valves, and in particular of the raphe system, is noted and explained with reference to their formation; with respect to this asymmetry two configurations of the valves can occur (named cis and trans types) and the distribution of these in raphid genera is discussed briefly. In view of the lack of evidence in raphid diatoms supporting a classification of bands into copulae and pleurae, it is recommended that this practice be suspended.
ALGAL DISTRIBUTION IN A SMALL, INTERMITTENT STREAM RECEIVING ACID MINE‐DRAINAGE1
Authors: Lampkin Andrew J. , Sommerfeld Milton R. 
Published: August 2007

ABSTRACTLynx Creek, a small intermittent creek in the Bradshaw Mountains of Arizona, is subjected to drainage from an abandoned copper mine. The mine‐drainage decreases the pH of the Creek about three units and greatly increases sulfate and heavy metal concentrations. Chemical recovery of the Creek occurs downstream through precipitation of metal hydroxides and dilution by tributaries. Changes in Creek chemistry are accompanied by changes in algal flora. Above the mine and downstream after substantial recovery, the flora is dominated by Tribonema affine4, Achnanthes spp., and Synedra ulna and several zygnematacean species. In the mine seep entering the Creek and in the Creek just below the seep the flora is reduced in species richness and dominated in abundance by Microthamnion kuetzingianum and Eunotia tenella.
TEMPERATURE EFFECTS ON SILICON LIMITED GROWTH OF THE LAKE MICHIGAN DIATOM STEPHANODISCUS MINUTUS (BACILLARIOPHYCEAE)1
Authors: Mechling Joyce A. , Kilham Susan Soltau 
Published: August 2007

ABSTRACTThe effect of temperature on the silicon limited growth and nutrient kinetics of Stephanodiscus minutus Grun. was examined using batch and semicontinuous culture methods. Short‐term batch culture methods gave maximum growth rates which were essentially constant over the temperature range of 10° to 20°C (μ3= 0.71–0.80 d−1). The half‐saturation constant for growth (Ks) was significantly lowest at 10°C (Ks= 0.31 μM Si; 0.22–0.41), and higher at both 15°C (Ks= 1.03 μM Si; 0.68–1.47) and 20°C (Ks= 0.88 μM Si; 0.60–1.22). Two methods were used to evaluate the semicontinuous experiments. The Droop relationship showed that the minimum cell quota was about 1.50 × 10−7 nmol Si cell−1, but there was much overlap in the results at all three temperatures. The Monod growth relationship for the semicontinuous experiments gave estimates of Ks which were lowest at 15°C (Ks= 0.12 μM Si), and higher at 10°C (Ks= 0.68 μM Si) and 20°C (Ks= 1.24 μM Si), although 95% confidence intervals overlapped. The maximum growth rate estimates for the semicontinuous experiments were similar at 10° and 15°, and higher at 20°C, but the number of points used in making the calculations makes the results less reliable than those from batch cultures. Generally, there were no consistent significant differences in the silicon limited growth of S. minutus over the temperature range studied. Our values of Ks for S. minutus are the lowest recorded for a freshwater diatom, and are consistent with the distribution of this species in nature. Generally, this species becomes abundant in areas with high phosphorus loading and very low silicon levels (low Si:P loading rates). Stephanodiscus species are also fossil indicators of eutrophication in north temperate lakes.
PHYSIOLOGICAL RESPONSES OF ANABAENA VARIABILIS (CYANOPHYCEAE) TO INSTANTANEOUS EXPOSURE TO VARIOUS COMBINATIONS OF LIGHT INTENSITY AND TEMPERATURE1
Authors: Collins Carol D. , Boylen Charles W. 
Published: August 2007

ABSTRACTLight intensity and temperature interactions have a complex effect on the physiological process rates of the filamentous bluegreen alga Anabaena variabilis Kütz. The optimum temperature for photosynthesis increased with increasing light intensity from 10°C at 42 μE·m−2·s−1 to 35°C at 562 μE·m−2·s−1. The light saturation parameter, IK, increased with increasing temperatures. The maximum photosynthetic rate (2.0 g C·g dry wt.−1·d−1) occurred at 35°C and 564 μE·m−2·s−1. At 15°C, the maximum rate was 1.25 g C·g dry wt.−1·d−1 at 332 μE·m−2·s−1. The dark respiration rate increased exponentially with temperature. Under favorable conditions of light intensity and temperature the percent of extracellular release of dissolved organic carbon was less than 5% of the total C fixed. This release increased to nearly 40% under combinations of low light intensity and high temperature. A mathematical model was developed to simulate the interaction of light intensity and temperature on photosynthetic rate. The interactive effects were represented by making the light‐saturation parameters a function of temperature.
SCANNING ELECTRON MICROSCOPY OF CORALLINA AND HALIPTILON (CORALLINACEAE, RHODOPHYTA): SURFACE FEATURES AND THEIR TAXONOMIC IMPLICATIONS1
Authors: Garbary David J. , Johansen H. W. 
Published: August 2007

ABSTRACTScanning electron microscopy of intergenicula in members of the subfamily Corallinoideae reveals two distinctive surface morphologies: a Corallina‐type (C‐type) with round to irregular cell outlines and round trichocyte bases, and a Jania‐type (J‐type) with elongate, polygonal cell outlines and elongate trichocyte bases with excentric pores. The surface results from the calcified lateral walls of the epithallial cells projecting up from around collapsed protoplasts. Since J‐type surfaces and trichocytes only occur in unequivocal members of the tribe Janieae—especially the genera Jania and Haliptilon, the presence of J‐type surfaces in questionable members of Corallina reveals that they in fact belong to Haliptilon. Thus the two surface types clarify previously difficult taxonomic distinctions between Haliptilon and Corallina and allow identification to genus from purely vegetative material. Seventeen new combinations in Haliptilon are proposed. These results have considerable biogeographic implications with tropical species found to belong to Haliptilon, and Corallina sensu stricto being recognized primarily as a temperate and cold water genus.