scholarly journals Studies on Ectocarpus in Culture II. Growth and Nutrition of a Bacteria-Free Culture

1961 ◽  
Vol 41 (2) ◽  
pp. 287-304 ◽  
Author(s):  
G. T. Boalch
Keyword(s):  
Growth Rate ◽  
Sea Water ◽  
Culture Media ◽  
Potassium Phosphate ◽  
Dry Weight ◽  
Maximum Growth ◽  
Potassium Nitrate ◽  
Natural Seawater ◽  
Growth And Nutrition ◽  
Water Media

The growth and nutrition of Ectocarpus confervoides has been studied in bacteria-free cultures. Growth was estimated by dry weights determined under controlled conditions. A method for inoculation of cultures of filamentous algae is described and a table of culture media is given. Following a lag of 5–7 days there was a period of growth, which was not truly exponential, extending over a period of 35 days. Calculation of the relative growth constant for the early stages of growth indicated that the alga doubled its dry weight every 6–7 days. Cultures of Ectocarpus remained viable for over 1 year in the light and for over 100 days in the dark. In natural sea-water media the maximum growth was brought about by the addition of 0·5 mM potassium nitrate and 0·1 mM potassium phosphate. Ferric chloride had no effect on growth but additions of manganese chloride did cause some stimulation. Additions of some complex organic mixtures slightly increased growth but Ectocarpus was unable to grow on a range of organic carbon source in the dark. The optimum salinity at 20° C was somewhat higher than that of natural sea water but was apparently lower at 15° C. The optimum pH was 8·0. Light intensities between 1350 and 16,000 lux had no marked effects on the growth rate but did effect the lag, the optimum for this being 7000 lux. Temperature also had no effect on the growth rate but did effect the lag. The optimum was 15–20° C but there was growth between 10 and 25° C. A considerable range of artificial sea waters, with and without organic additions was investigated, in no case did they give a yield greater than two-thirds that in natural seawater media. These results are discussed in relation to other workers findings.

The response to salinity of a population of Dactyloctenium aegyptium from a saline habitat in southern Nigeria

1994 ◽  
Vol 10 (2) ◽  
pp. 219-228 ◽  
Author(s):  
A. A. Adu ◽  
A. R. Yeo ◽  
O. T. Okusanya
Keyword(s):  
Sea Water ◽  
Nutrient Deficiency ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Potassium Nitrate ◽  
Inhibitory Effect ◽  
Ion Concentration ◽  
Dactyloctenium Aegyptium ◽  
Sodium And Potassium ◽  
Water Contents

ABSTRACTThe effects of salinity upon the growth, photosynthesis, ion and water contents of a population of Dactyloctenium aegyptium originating from a saline site in Nigeria were investigated. Growth was unaffected by a salinity of 10% artificial sea water, but was reduced by one third in 20% and by two thirds in 30% artificial sea water respectively. Initial adjustment to salinity was due both to increases in the concentrations of sodium and potassium per unit dry weight and to reduced hydration, the latter being the more important at higher salinities. The increase in ion concentration in the cell sap balanced the salinity of the medium at 10% artificial sea water, but was excessive at higher concentrations of sea water. Net photosynthesis was unaffected by 10% artificial sea water but declined at higher salinities. The potassium content of the plants did not fall below 200–250 mM, and the sodium to potassium ratio did not exceed three, even at the highest salinities. Variation in the concentration of nutrients (potassium, nitrate and sulphate) in the medium in the presence of 25% artificial sea water had significant effects upon growth, but these were small in relation to the inhibitory effect of the salinity.The reduction in growth could not be attributed to lack of osmotic adjustment or to nutrient deficiency, and was probably due to ion toxicity within the leaves. The tolerance to reduced hydration, combined with the ability to germinate in saline conditions previously observed, could enable D. aegyptium to establish in a saline soil. The population did not exhibit any halophytic characteristics but did survive with a low growth rate at salinities up to 50% artificial sea water. It is concluded that the species was able to colonize the saline site because of its inherent adaptability, rather than the possession of an ecotype adapted to saline conditions.

scholarly journals TEMPERATURE AND NITRATE CONCENTRATION EFFECT ON THE ABUNDANCE AND GROWTH RATE OF MELOSIRA SP.

2021 ◽  
Vol 7 (2) ◽  
pp. 185-194
Author(s):  
Nita Rukminasari ◽  
Sharifuddin Andy Omar ◽  
Muhammad Lukman
Keyword(s):  
Fatty Acids ◽  
Growth Rate ◽  
Free Fatty Acids ◽  
Culture Media ◽  
Nitrate Concentration ◽  
Dry Weight ◽  
Organic C ◽  
Randomized Design ◽  
Significant Difference ◽  
Nitrate Concentrations

Microalgae are one of the natural resources that have high potential as a source of biofuels, one of them is the marine microalgae Melosira sp.. The objective of this study was to determine the effect of increasing temperature and nitrate concentration on the abundance, growth rate, biomass, organic C-content and free fatty acids of Melosira sp.. A Completely Randomized Design was used for this experiment with four temperature treatments and three nitrate concentrations treatments  in microalgae test planting media. The test microalgae were cultured for 21 days, while the abundance of Melosira sp..was carried out every 3rd day, while for other parameters measurements were made at the end of the experiment. The results showed that the increasing in temperature and nitrate concentration in culture media significantly affected the abundance of Melosira sp.. Meanwhile, the results of statistical analysis showed that the increase in temperature and concentration of culture media did not have a significant effect on biomass except at 30°C treatment, the dry weight of Melosira sp. was only significantly different between the nitrate concentrations of 0.0 g/L and 0.4 g/L. For the content of C-organic and free fatty acids generally showed a significant difference between treating temperature and nitrate concentration in the culture media.

Growth and reproduction of Macoma balthica (L.) on a mud flat in the Fraser River estuary, British Columbia

1983 ◽  
Vol 61 (4) ◽  
pp. 887-894 ◽  
Author(s):  
E. R. McGreer
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Shell Height ◽  
Macoma Balthica ◽  
River Estuary ◽  
Dry Weight ◽  
Maximum Growth ◽  
Fraser River ◽  
Mud Flat ◽  
Growth And Reproduction

Growth and reproduction of the bivalve, Macoma balthica (Linnaeus, 1758) was studied for one year (April 1977 – March 1978) on an intertidal mud flat in the Fraser River estuary, British Columbia. The maximum number of individuals (1830/m2) occurred in April, then steadily declined throughout the year. Spawning occurred between mid-June and late July but recruitment was slow and prolonged. Peak spatfall (age 0+ individuals) did not occur until the following March when a maximum density of only 410/m2 for newly settled spat was observed. The oldest animals found were 5+ years of age. Maximum growth took place from April through July. The growth rate measured was one of the highest recorded for any M. balthica population. A direct relationship between high water temperatures, a fast growth rate, and reduced longevity was apparent. A regression of body weight on shell height was used to calculate a condition factor (CF), which reached its highest value during growth and its lowest value immediately after spawning. The mean annual biomass measured was 2.96 g dry weight per square metre.

scholarly journals The Utilization of Rum Slops by Marine Bacteria. I. Isolation of Efficient Strains.

1969 ◽  
Vol 63 (2) ◽  
pp. 180-188
Author(s):  
T. R. Tosteson ◽  
D. R. Hale
Keyword(s):  
Liquid Culture ◽  
Sea Water ◽  
Culture Media ◽  
Growth Inhibitors ◽  
Bacterial Strains ◽  
Marine Communities ◽  
Sea Grass ◽  
Water Media ◽  
Marine Mud ◽  
Colony Shape

Bacterial strains have been isolated from selected marine communities, and their ability to utilize and/or detoxify the crude slops has been assessed. These bacterial strains were isolated from 1) marine mud, 2) decaying sea grass, Thalassia testudinum, 3) the surfaces of the roots of the mangrove Rhizophora mangle and 4) gravel sediment. The isolates were grown on solid modified sea water media containing slops. A total of twenty isolates were obtained from the slops media. Colony shape and color of these strains were determined. The slops isolates were grown in liquid culture media in the presence of slops. Eight of the original isolates grew in this media, showing little tendency to form aggregates. The growth of these strains was examined in the presence of variable concentrations of the slops. The results of this study indicate that the growth inhibitors in the slops can be partially detoxified by these bacterial strains, and the remaining material utilized for population growth.

scholarly journals Growth rate and haploidization of Aspergillus niger on medium containing p-fluorophenylalanine

1968 ◽  
Vol 12 (3) ◽  
pp. 305-315 ◽  
Author(s):  
Pol Lhoas
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Curves ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Complete Medium ◽  
Acid Analogue ◽  
Mean Size ◽  
The Mean

1. The comparison of the dry weight of thin layer haploid and diploid colonies of A. niger on complete medium and complete medium supplemented with p-fluoro-phenylalanine led to the conclusion that there is a difference in growth rates of hyphae under these different conditions.2. The growth curves of the same strains on both media were established. On complete medium, haploids and diploid show a growth rate increasing linearly for about 20 h after germination and reaching a maximum which is then maintained. On p-fluorophenylalanine, the haploids show a similar curve, although the maximum growth rate reached and maintained is about half that on complete medium; for the diploid, however, the maximum is less than the corresponding one in the haploid and, once this maximum has been reached, the growth rate goes down linearly to a very low value which is then maintained.3. The cytological study of the hyphal tip cell showed, in the presence of the amino acid analogue, a reduction of the mean size of the diploid nuclei together with an increase of the number of nuclear fragments. This explains the growth rates observed and is accepted as a confirmation that p-fluorophenylalanine, by its action on the mitosis, favours chromosome losses which lead finally to the production of haploid nuclei.

scholarly journals A note on Stichococcus bacillaris Naeg. and some species of Chlorella as marine algae

1957 ◽  
Vol 36 (1) ◽  
pp. 111-114 ◽  
Author(s):  
E. A. George
Keyword(s):  
Growth Rate ◽  
Marine Algae ◽  
Sea Water ◽  
Culture Collection ◽  
Reference Number ◽  
Water Media ◽  
Clonal Lines ◽  
Stichococcus Bacillaris

Several strains of Stichococcus bacillaris Naeg. and of the marine S. cylindricus Butcher were all found to fit morphologically in Naegeli's species. Both the marine and non-marine strains grow well in either fresh- or sea-water media. S. cylindricus must therefore be regarded as a synonym of S. bacillaris. Three marine Chlorella strains including C. ovalis Butcher and C. stigmatophora Butcher were also found to be quite unexacting about salinity. The significance of small differences, particularly of growth rate, is discussed with regard to non-sexual organisms. In general, widely based species are advocated for such organisms, with the clonal lines, where appropriate, designated by the reference number of a recognized culture collection.

Growth and biomass allocation of Ruppia occidentalis in three lakes, differing in salinity

1985 ◽  
Vol 63 (11) ◽  
pp. 2004-2014 ◽  
Author(s):  
Brian C. Husband ◽  
Michael Hickman
Keyword(s):  
Growth Rate ◽  
Biomass Allocation ◽  
Dry Weight ◽  
Maximum Growth ◽  
Freshwater Lake ◽  
Lake Chemistry ◽  
Shoot Dry Weight ◽  
Wide Range ◽  
Total Dry Weight ◽  
Root:Shoot Ratios

The hypothesis that the growth and distribution of Ruppia occidentalis S. Wats. increases with increasing salinity in Alberta lakes was investigated by comparing populations of Ruppia from three lakes, spanning a wide range of total dissolved solids (0.3–6.2‰). Growth and biomass allocation of individuals were correlated with lake chemistry. Plants from the freshwater lake exhibited characters associated with moderate chemical deficiency, including decreased growth rate, decreased reproductive output, and high root:shoot ratios. The proportion of total dry weight decreased in roots and increased in shoots with salinity but varied little among depths within the lake. Changes in shoot dry weight were the result of vertical growth in the saline lakes but the result of horizontal growth through tiller production in the freshwater lake. Although salinity did not affect the reproductive effort in flowering individuals, the number of flowering individuals in the population increased with salinity. The frequency of occurrence and percentage cover of Ruppia within each lake reflect its respective growth rate and reproduction. The within-lake distributions are characterized by significant interactions between salinity and both depth distribution and substratum type. Saline conditions are required by Ruppia and not merely tolerated for maximum growth and reproduction. Its absence from many freshwater lakes is due most likely to chemical constraints on survival or on the competitive ability of Ruppia.

The function of a toluene-degrading bacterial community in a waste gas trickling filter

1999 ◽  
Vol 39 (7) ◽  
pp. 131-137 ◽  
Author(s):  
Anne R. Pedersen ◽  
Erik Arvin
Keyword(s):  
Growth Rate ◽  
Volume Fraction ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Trickling Filter ◽  
Biofilm Growth ◽  
Waste Gas ◽  
Degrading Bacteria ◽  
Food Web Model

The function of a community of toluene-degrading bacteria in a biofilm system was investigated with regard to growth and toluene degradation in order to investigate substrate interactions in the community. This was done by the combination of experimental observations using a specific oligonucleotide 16S ribosomal RNA probe targeting the toluene-degrading species Pseudomonas putida, and by computer simulations (AQUASIM) of the biofilm growth based on a food web model. Biofilms were taken from a lab-scale trickling filter for treatment of toluene-polluted air. The biofilm growth and the activity of P. putida, a representative of the toluene-degrading species in the biofilm which have been described previously were simulated. The simulation indicated that the volume fraction of the toluene degraders in the biofilm decreased from 12% to only 2% (11% of dry weight) during two weeks. In spite of the low fraction in the biofilm, the toluene degraders supported growth of the dominating part of non-toluene-degrading heterotrophs in the biofilm, as toluene was the sole carbon source supplied to the system. The maximum intrinsic growth rate of P. putida in the biofilm was only 20% of the maximum growth rate determined in a batch experiment with suspended P. putida cells.

scholarly journals Efecto de coyolillo (Cyperus rotundus) sobre el crecimiento de canavalia (Canavalia ensiformis).

2016 ◽  
Vol 8 (1) ◽  
pp. 115
Author(s):  
Francisco Lara ◽  
Leopoldo Serrano ◽  
Carlos Aguirre ◽  
Raúl Villatoro
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
Maximum Growth ◽  
Cyperus Rotundus ◽  
Maximum Height ◽  
Average Growth ◽  
Absolute Growth ◽  
The University ◽  
Training Station ◽  
And Training

During the summer 1995, at the Experimental and Training Station of the Agronomy School of the University of El Salvador, an experiment was established by alternating sword bean (0.80 m. x 0.50 m) with maize (0.80 m. x 0.30 m.), under zero management. The plot was divided in two areas one with a high infestation of “coyolillo” and other with a predominance of wide-leaf weeds, such as Baltimora recta, Melantera sp., Lantana camara, and Panicum sp. Samples were taken in each area every 10 days, by using 10 sword plants to determine the following variables: plant height, dry weight, absolute growth rate, and relative average growth rate. The infestation with Cyperus initially oscillated between 1200 to 1650 young sprouts/m2. The experiment was analyzed under the concept of paired plots. The results indicated significant differences for the height of Canavalia plants, increasing from 10 dds to 20 and 30 dds, reaching the maximum growth in the plot without Cyperus, reaching 108 cm at 40 dds, in contrast with plants with competence by Cyperus, which attained a maximum height of 82.9 cm. This showed an unfavorable competition to Canavalia, which was also supported by the accumulation of dry matter.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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