bluuebunny/crossref_metadata_2025_split huggingface dataset:
ECOLOGY AND NATURAL HISTORY OF IRIDAEA CORDATA (GIGARTINALES, RHODOPHYTA) GROWTH1
Authors: Hansen Judith E. 
Published: August 2007

ABSTRACTThe in situ growth, maturation and senescence, of central California Iridaea cordata (Turner) Bory was studied. This ontogenetic progression was quantified by measuring development and growth of: i) individually tagged blades, and ii) populations of blades within cumulative (1‐yr duration) and seasonal experimental plots. Greatest growth and longest life span were exhibited by winter‐spring initiated blades, and were correlated with a rapid increase, in irradiance, but not with either seawater temperature or nutrients. Tagging studies showed that reproductive maturation and senescence of blades occurred throughout the year, irrespective of date tagged, growth rate or size. Moreover, the majority of blades continued to elongate following maturation, and some matured within 3 mo of initiation at all seasons but winter. At the population level maturation took place primarily during summer‐autumn when 90 ±2% of the population was mature. The majority of the population senesces or “dies back” during autumn‐winter. It is concluded that in situ, the blades are derived almost totally via vegetative means involving perennation. This indirectly suggests that sexual reproduction or the success of sporeling development are marginal. Additionally, the species is perennial with annually deciduous blades, characterized by both rapid growth and maturation.
COMPARISON OF ATTACHED DIATOM COMMUNITIES ON NATURAL AND ARTIFICIAL SUBSTRATES1
Authors: Siver Peter A. 
Published: August 2007

ABSTRACTA study of attached diatom communities on artificial and natural substrates was conducted in Wheelwright Pond, New Hampshire, during 1975. There were differences in the species composition growing on artificial glass slides and natural substrates. The slides favored the accumulation of Achnanthes minutissima Kütz. and decreased the relative abundance of Eunotia incisa W. Sm. ex. Greg. and Cocconeis placentula v. euglypta (Ehr.) Cleve. Large growths of planktonic species were also noted on the slides. Compositional differences between slides positioned at 15–30 cm (upper) and 1 m (lower) from the surface of the water were minimal. A similar community composition of periphytic diatoms was found on five aquatic macrophytes.
ADAPTATION OF STYROFOAM SUBSTRATE TO BENTHIC ALGAL PRODUCTIVITY STUDIES IN LAKE TAHOE, CALIFORNIA‐NEVADA1
Authors: Flint R. Warren , Richards Robert C. , Goldman Charles R. 
Published: August 2007

ABSTRACTA routine sampling technique has been developed using artificial styrofoam substrate to estimate benthic algal productivity in the littoral zone of lakes. Estimation of maximum carbon fixed in Lake Tahoe ranged from 11.1 mg C·m−2· day−1 at 0.5 m to 17.1 mg C·m−2· day−1 at 1.0 m. Estimates were made for communities composed of both diatom and green algal populations in water between 0.5 and 3.0 m. Maximum productivity occurred between 1–2 m. The technique developed can give comparable estimates of productivity if adequate replication is undertaken to decrease problems associated with periphytic heterogeneity.
TWO NEW SPECIES OF PSEUDOKEPHYRION (CHRYSOPHYCEAE) IN THE PLANKTON OF A LAKE1
Authors: Nicholls Kenneth H. 
Published: August 2007

ABSTRACTTwo new species of Pseudokephyrion are described from Little Aurora Lake, Ontario, Canada. The distribution of both P. taeniatum sp. nov. and P. auroreum sp. nov. is restricted, for reasons which are not clear; neither species was found in samples from lakes adjacent to Little Aurora Lake. All lakes in the vicinity are very dilute, oligotrophic and acidic.
EPIPELIC AND EPILITHIC DIATOM ASSEMBLAGES IN MONTEZUMA WELL NATIONAL MONUMENT, ARIZONA1
Authors: Czarnecki David B. 
Published: August 2007

ABSTRACTEpipelic and epilithic diatom assemblages in Montezuma Well National Monument, Arizona, were identified and analyzed by H' (species diversity), species number, J' (evenness), relative abundance, SIMI (similarity index), and DI (dissimilarity index) values. The epipelic assemblage was found to be a tri‐dominant association ofCyclotella pseudostelligera f. parvaCzar. & Blinn,Cocconeis placentulavar.lineata(Ehr.) V.H. andAchnanthes linearis(W. Sm.) Grun. The epilithic assemblage was a tri‐dominant association ofRhoicosphenia curvata(Kütz.) Grun. ex Rabh.,Cy. Pseudostelligera f. parvaandSynedra ulna(Nitz.) Ehr. Both associations persisted throughout the year. Of the 83 taxa observed, 51 were common to both assemblages, 24 were restricted to the epipelon, and 8 were restricted to the epilithon. On a yearly basis, the epipelic assemblage exhibited less diversity (H') than the epilithon, even though the latter exhibited fewer taxa. The use of mean diversity values was also determined to be unacceptable.Cy. Pseudostelligera f. parvaandS. ulnaappeared more abundant under high light intensity and duration,Fragilaria construensvar.venter(Ehr.) Grun. favored low light intensity and duration, whereasA. linearis, R. curvataandCo. placentulavar.lineatawere tolerant of a variety of intensities and durations. On a yearly basis, both assemblages exhibited slight similarity (SIMI, DI). The use of SIMI values for comparing assemblages with few highly abundant taxa was determined to be unacceptable and under these conditions, the use of DI was recommended.
INTERACTION (ALLELOPATHY) BETWEEN MARINE DIATOMS: THALASSIOSIRA PSEUDONANA AND PHAEODACTYLUM TRICORNUTUM1
Authors: Sharp Jonathan H. , Underhill Peter A. , Hughes David J. 
Published: August 2007

ABSTRACTTwo marine diatoms were studied singly and in mixed culture. Thalassiosira pseudonana (Hust.) Hade & Heimdal was capable of a higher growth rate (μmax) than Phaeodactylum tricornutum Bohlin. In two‐species batch cultures P. tricornutum took over in the latter portion of the exponential phase, possibly due to allelopathy. The filtrate from this species caused an initial lag phase and a reduced terminal population density for T. pseudonana. Two‐species continuous cultures showed verification of these interactions. At high dilution rate (i.e., high growth rate) P. tricornutum washed out when added at low density, whereas T. pseudonana maintained constant cell density. However, when sufficient density of P. tricornutum was added as a contaminant, both species washed out. At a lower dilution rate P. tricornutum increased in density when added and eventually reached a stable population; T. pseudonana then washed out.
MITOSIS AND CLEAVAGE DURING ZOOSPOROGENESIS IN SEVERAL COCCOID GREEN ALGAE1
Authors: Deason Temd R. , O'Kelley Joseph C. 
Published: August 2007

ABSTRACTThe fine structure of mitosis and cleavage inAxilosphaera vegetataCox & Deason,Chlorococcum echinozygotumStarr,Chlorosarcinopsis eremiChantanachat&Bold,Nautococcus mammilatusKorshikoff,N. terrestrisArchibald,N. solutaArchibald,Neospongiococcum solitariumDeason, andTetracystis aeriaBrown & Bold was observed. All possess a phycoplast, but differences in basal body position during mitosis were observed.Nautococcus mammilatusdiffers from the others as protoplast rotation occurs in many cells prior to cleavage.
SEASONAL CYCLING OF ALGAL NUTRIENT LIMITATION IN CHAUTAUQUA LAKE, NEW YORK1
Authors: Storch Thomas A. , Dietrich Geoffrey A. 
Published: August 2007

ABSTRACTAlgal nutrient enrichment bioassays were conducted between May 1975 and August 1978 using water samples collected from Chautauqua Lake, New York. Photosynthetic fixation rates of natural phytoplankton assemblages were enhanced by additions of phosphorus and nitrogen, although enrichment with other nutrients had no significant stimulatory effect on algal photosynthesis. Whereas phosphorus stimulated in spring and early summer, both nitrogen and phosphorus enhanced photosynthesis in midsummer and fall. Relative to the effect of phosphorus enrichment, enhancement of photosynthesis by nitrogen during the summer and fall was highest in the northern part of the lake. During the period of ice cover, photosynthesis did not appear to be limited by nutrients in that nutrient additions (P, N, Si, C, Fe, trace metals) did not enhance fixation rates. Observed temporal fluctuations in the response of the algae to P and N correlated with changes in the lake water N:P ratio as well as with temporal changes in dissolved orthophosphate and nitrate‐nitrite nitrogen. The N:P ratio decreased drastically in the summer and remained at ca. 10 or less through mid‐fall, suggesting that N concentrations were inadequate for the non‐N‐fixing phytoplankton. Studies over 3 yr indicate that states of P and N limitation undergo time‐space fluctuations that occur in a cyclic pattern in the surface waters of Chautauqua Lake.
RECYCLING OF METABOLIZED IRON BY THE MARINE DINOFLAGELLATE AMPHIDINIUM CARTERAE1
Authors: Frey Bruce E. , Small Lawrence F. 
Published: August 2007

ABSTRACTSenescent, iron‐limited cultures of Amphidinium carterae Hulburt were used to detect the presence of iron made available for phytoplankton growth by recycling of metabolized iron from disrupted cells. Both physical disruption of cells and physical disruption plus exposure to a low pH were tested. The test cultures remained viable over long periods of time, and were stimulated to full growth by the addition of Fe, but not by the addition of any other nutrients. Simple physical disruption of cells caused only a very slow release of available Fe, while disruption of cells plus exposure to a low pH resulted in a rapid release of available Fe. It is suggested that the digestive processes of herbivores are instrumental in the rapid regeneration of Fe as a nutrient available for phytoplankton growth.
ULTRASTRUCTURE OF TETRASPOROGENESIS INPALMARIA PALMATA(RHODOPHYTA)1
Authors: Pueschel Curt M. 
Published: August 2007

ABSTRACTThe tetrasporangial initial inPalmaria palmata(L.) O. Kuntze (formerlyRhodymenia palmata(L.) Greville) arises from a cortex cell which enlarges and deposits a protein‐rich wall layer. This cell undergoes mitosis to form a tetrasporocyte and a stalk cell. Synaptonemal complexes are formed in the sporocyte nucleus while in the cytoplasm floridean starch is deposited in association with ER or with particles presumed to be ribosomes. Microbody‐like structures become numerous between the nuclear envelope and perinuclear ER, and clusters of non‐membranous, spherical structures also are associated with the nucleus. Chromatin condensation is reversed following pachytene and a prolonged diffuse stage ensues, when dictyosomes and ER produce vesicles which deposit mucilage rich in sulfated and acidic polysaccharides around the tetrasporocyte. A conspicuous lenticular thickening of the mucilage sheath develops at the apical end of the sporangium. Dictyosomes are frequently associated with mitochondria which may be associated with chloroplasts. Following nuclear divisions the tetrasporocyte is cleaved into four spores by sequentially initiated, but simultaneously completed periclinal and anticlinal furrows. When mucilage deposition ceases, the dictyosomes begin to produce vesicles with glycoprotein‐rich contents. These vesicles are abundant in released tetraspores, and they probably contain adhesive material aiding in the attachment of the liberated spores.
MORPHOLOGY OF THE SUBANTARCTIC RED ALGA CENACRUM SUBSUTUM GEN. ET SP. NOV. (RHODYMENIALES) FROM MACQUARIE ISLAND1
Authors: Richer Robert W. , Kraft Gerald T. 
Published: August 2007

ABSTRACTThe red alga Cenacrum subsutum gen. et sp. nov. is described from material collected at Macquarie Island in the subantarctic between November 1977 and February 1978. The habit and carposporophyte development are similar to members of the family Rhodymeniaceae (Rhodymeniales), but certain vegetative features are unique. The frond is a variously incised or lobed foliose blade with hollow apices above and a medulla which becomes progressively filled basipetally with ingrowing rhizoidal filaments. Details of carpogonial branch, auxiliary cell, connecting cell and gonimoblast anatomy are given, as well as observations on the habitats and distribution of the species.
SEASONAL CHANGES IN STRUCTURE OF A SUBMERGED BLUEGREEN ALGAL/BACTERIAL COMMUNITY FROM A GEOTHERMAL HOTSPRING1
Authors: Fagerberg Wayne R. , Arnott Howard J. 
Published: August 2007

ABSTRACTThe species (cytospecies) structure and seasonal dynamics of a thermophilic bluegreen algal/bacterial community from Mimbres, New Mexico are described. Using stereological techniques, several common quantitative ecological parameters (biomass, density, distribution measurements, Species Diversity Indices, importance values) were described for the community growing ca. 1 m beneath the water surface on the inner walls of a concrete cistern. Temperature and pH were relatively constant while water flow rates, duration and intensity of light showed seasonal variation. The total volume of the mat occupied by living organisms did not exceed 2% during the entire year. The remaining volume was occupied by gas and water bubble chambers, gelatinous matrix, empty tubes, mineral deposits, and water. The total biomass remained constant except during a period of severe, seasonal light reduction (November). Species Diversity Indices, density and importance values for the bluegreen algal and bacterial populations showed seasonal changes. The three dominant bluegreen algal cytospecies which represented the greatest amount of biomass alternated in their abundance on a seasonal basis while the three dominant bacterial cytospecies remained the same throughout the period of study. Although considerable season change occurred in the species structure of this community, the total living volume remained relatively constant with the major changes in the bluegreen algal populations. Many of the seasonal changes observed appear to correlate with seasonal changes in light intensity and duration.
FINE STRUCTURE OF MITOSIS AND CLEAVAGE IN FRIEDMANNIA ISRAELENSIS (CHLOROPHYCEAE: CHLOROSARCINACEAE)1
Authors: Deason Temd R. , Ryals Phillip E. , O'Kelley Joseph C. , Bullock Kenneth W. 
Published: August 2007

ABSTRACTObservations on the ultrastructure of Friedmannia israelensis Chantanachat & Bold revealed the presence of a phycoplast and zoospores with cruciate rootlets. During mitosis, the nuclear envelope partially disintegrates and the basal bodies remain at the cell surface on either side of the developing cleavage furrow. The events during mitosis and cleavage in Friedmannia resemble those reported in the other green algae, Platymonas and Pleurastrum.
MICROFLUOROMETRIC MEASUREMENT OF DNA IN EUDORINA ELEGANS AND E. CALIFORNICA (CHOROPHYCEAE)1
Authors: Lindley Kemp C. , Doyle Gordon , Anderson Ron 
Published: August 2007

ABSTRACTThe fluorescent dye 2,5‐bis (4′‐aminophenyl (1′))‐1,3,4‐oxidiwle (BAO) was compared to the Feulgen procedure as a method for quantitative comparison of DNA levels in two species of Eudorina. The BAO procedure proved to be specific and as quantitative as the Feulgen procedure, and was more convenient and rapid. The DNA level of the nuclei of gonidial cells of Eudorina elegans Ehrenberg and E. californica (Shaw) Goldstein doubled prior to each division. The DNA level of the somatic, usually non‐dividing nuclei of E. californica did not vary from the IC (haploid) level.
NORTH CAROLINA MARINE ALGAE. IX. ONSLOWIA ENDOPHYTICA GEN. ET SP. NOV. (PHAEOPHYTA, SPHACELARIALES) AND NOTES ON OTHER NEW RECORDS FOR NORTH CAROLINA1
Authors: Searles Richard B. , Leister Geoffrey L. 
Published: August 2007

ABSTRACTFour benthic algae are reported here for the first time in the North Carolina flora. The new brown algal genus and species, Onslowia endophytica Searles, is described as an endophyte of Halymenia floridana from the North Carolina continental shelf. New records of Boodleopsis pusilla and Naccaria corymbosa from North Carolina constitute range extensions of these tropical species on the American coast north from Florida. Blastophysa rhizopus, an endophyte and epiphyte known from the North Atlantic coast of Europe and America as well as the Caribbean is reported from North Carolina for the first time and in a new host, Predaea feldmannii.
HOT WATER EXTRACTABLE PHOSPHORUS—AN INDICATOR OF NUTRITIONAL STATUS OF PERIDINIUM CINCTUM (DINOPHYCEAE) FROM LAKE KINNERET (ISRAEL)?1
Authors: Wynne David , Berman Thomas 
Published: August 2007

ABSTRACTThe intracellular levels of hot water extractable and total phosphorus were determined in the dinoflagellate Peridinium cinctum. f. westii (Lemm.) Lef. for natural samples from the bloom in Lake Kinneret and from laboratory cultures. Amounts of phosphorus (P) in the hot water fraction, relative to total cellular phosphorus, were similar in lake Peridinium and in cells grown in high ambient orthophosphate (Pi) media (3–6 mg P · l−1). The absolute amounts of hot water extractable P in natural cell and those cultured at lower Pi concentrations (0.02–0.05 mg P · 1−1) were similar, although average Pi in lake water were 4 μg · l−1. Under most growth conditions the hot water extract contained approximately equal amounts of molybdate reactive phosphorus (MRP) and non‐MRP. Short chain (6–9 units) polyphosphates (mol wt 630–950) probably constituted the bulk of the non‐MRP pool, which was hydrolysable by alkaline phosphatase and may serve as a precursor for a more permanent P store. Intracellular P levels and distribution were not directly dependent on external Pi concentrations but may be determined by the N:P atomic ratio or overall external ionic milieu. Peridinium grown in low ambient Pi released significant amounts of non‐MRP compounds. In Lake Kinneret, for at least most of the bloom period, Peridinium does not appear to be limited by P supply.
COMPARISON OF IN SITU PHOTOSYNTHETIC ACTIVITY OF EPIPHYTIC, EPIPELIC AND PLANKTONIC ALGAL COMMUNITIES IN AN OLIGOTROPHIC LAKE, SOUTHERN FINLAND1
Authors: Kairesalo Timo 
Published: August 2007

ABSTRACTThe photosynthetic activity of different algal communities at the outer edge of an Equisetum fluviatile L. stand in an oligotrophic lake (Pääjärvi, in southern Finland) was investigated. Production by the algal communities was measured simultaneously using a modified 14C‐method, and the results were related to the volume of algae and the available irradiance. The relative production rate (P/B quotient) of phytoplankton was ca. 3 × that of epiphyton and ca. 20 × that of epipelon. Epiphyton productivity remained almost constant although the algal volume varied greatly, suggesting that the surface layer of the algal community was mainly responsible for the photosynthetic activity. In the littoral area (at 1 m depth) primary production/m2 of lake surface by phytoplankton, epiphyton and epipelon was similar but in the littoriprofundal area (2–4 m) phytoplankton production was twice that of epipelon. Primary productivity of epiphyton and epipelon/m2 of substratum was about equal to phytoplankton productivity/m3 of water at the same irradiance. This relation provided a means of estimating the relative contributions of the different algal communities to the total algal production in the lake.
PRESENCE OF A SULFATED POLYSACCHARIDE IN THE EXTRACELLULAR MATRIX OFPLATYDORINA CAUDATA(VOLVOCALES, CHLOROPHYTA)1
Authors: Crayton M. A. 
Published: August 2007

ABSTRACTEvidence for the presence of a sulfated polysaccharide component within the extracellular matrix ofPlatydorina caudataKofoid is presented. In situ staining with alcian blue and toluidine blue O indicates accumulation of a sulfated polysaccharide in the matrix. The entire matrix was readily solubilized by a hot aqueous extraction and a sulfated proteoglycan complex was isolated. Thin‐layer chromatography of hydrolysates and infrared analysis and chemical desulfation of the intact molecule indicate that the polysaccharide component is principally an arabinogalactan with ester‐linked sulfate groups. Protease treatment of the extract revealed two distinct bands separable on cellulose acetate electrophoresis. The slower moving component was a sulfated glycoprotein while the faster moving component was a sulfated mucopolysaccharide essentially free of protein. This is the first report of specific chemical analyses and electrophoretic separation of a sulfated polysaccharide within the matrix of a member of the Volvocales. The cytochemistry and electrophoretic patterns of theP. caudatapreparation are compared with the same type of extract made fromChlamydomonas reinhardtiiDang. The possible evolutionary significance of the electrophoretic patterns is presented.
VALVE AND BAND MORPHOLOGY OF SOME FRESHWATER DIATOMS. II. INTEGRATION OF VALVES AND BANDS IN NAVICULA CONFERVACEA VAR. CONFERVACEA12
Authors: Rosowski James R. 
Published: August 2007

ABSTRACTChemically cleaned and critical‐point dried cells of a clonal culture were examined with scanning electron microscopy. Cells form filaments by valve‐to‐valve connections maintained by organic material which adheres to the central area of the valve face. Bending of filaments is probably restricted to some extent by the articulation of overlapping spatulate marginal spines with an adjacent underlapping set of much shorter spines (ridges), and with the mantle edge itself. Cell division results in three possible spine patterns for each cell: a set of overlapping and a set of underlapping spines; no overlapping sets of spines (two underlapping); or two sets of overlapping spines (no underlapping). Each filament inherits cells with spine set patterns in the ratio of 2 (with 1 set overlapping): 1 (with no sets overlapping): 1 (with 2 sets overlapping). Valvocopulae are shaped similarly to pleurae except that the partes exteriores of the valvocopulae are wider. The pars interior of both is delimited by an advalvar row of pores continuous around the cell apex. The pars exterior also has a row of pores, but it is median in the valvocopula and first pleura and does not continue around the cell apex. The valvocopulae always underlap the mantle and the pleurae always underlap their preceding band. The ends of both appeared attached, but may become free in acid‐cleaned preparations. Bands alternate with each other so that the ends of the valvocopula attach to the first continuous apical portion of the first pleura; the ends of the first pleura attach in that same fashion to the second pleura but at the opposite apex; and all subsequent pleurae alternate in the same fashion with up to at least 13 pleurae/epicingulum. The continuous apical portion of each band is elevated so that a functional (but not structural) ligula is formed, with the continuous apical portion of alternate bands becoming adjacent and underlapping each other only in this region. The valvocopulae in a single cell, or of adjacent cells, may have their continuous apical ends on the same or on opposite apices. It is recommended that N. confervacea var. peregrina (W. Sm.) Grun. be merged with the nominate variety.
CHLOROPELTA GEN. NOV., AN ULVACEOUS GREEN ALGA WITH A DIFFERENT TYPE.OF DEVELOPMENT1
Authors: Tanner Christopher E. 
Published: August 2007

ABSTRACTA diminutive, distromatic ulvaceous green alga was collected in southern California and studied in culture. The initial stages of development resemble those found in the Ulvaceae sensu Bliding. Germlings pass through a uniseriate filamentous stage, a multiseriate stage and a monostromatic saccate stage. At this stage the development departs from the developmental patterns found in the Ulvaceae. Each cell of the monostromatic upright portion of the germling undergoes a single division in a plane parallel to the surface of the germling to form a distromatic saccate germling. Rupture of the apical end of the germling and continued growth eventually results in a peltate distromatic alga superficially resembling Ulva. Based on the developmental pattern, which is unique to the green algae, the new genus Chloropelta gen. nov. and new species Chloropelta caespitosa sp. nov. are proposed for this alga.