Marine Phytoplankton Photosynthesis as a Function of Light Intensity: A Comparison of Methods

1964 ◽  
Vol 21 (1) ◽  
pp. 159-181 ◽  
Author(s):  
C. D. McAllister ◽  
N. Shah ◽  
J. D. H. Strickland
Keyword(s):  
Cell Division ◽  
Skeletonema Costatum ◽  
Algal Growth ◽  
Net Photosynthesis ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Fluorescent Light ◽  
Particulate Carbon ◽  
Gross Photosynthesis ◽  
Light Intensities

An apparatus is described in which the constant for exponential algal growth has been determined as a function of light at controlled temperature. Studies were made of bacteria-free cultures of Skeletonema costatum and Dunaliella tertiolecta grown at the optimum temperature for cell division in media with and without adequate nitrate and phosphate. Less complete studies were made of the behaviour of Monochrysis lutheri and Amphidinium carteri. In all experiments the growth constants were determined at known light intensities, expressed in the energy units, langlies/minute, using light of a known spectral distribution similar to sunlight shining through a few metres of coastal sea water.Growth constants were determined for the following processes: increase of cellular carbon, chlorophylls a, b or c, carotenoids, cell numbers and photosynthesis measured both by oxygen evolution (net and gross) and by the uptake of C-14 labelled carbonate.The rate of maximum photosynthesis occurred when the illumination reached about 0.1 ly/min and little or no light inhibition occurred when the intensity was increased to as high as 0.4 ly/min. Respiration was about 10% of maximum gross photosynthesis. This fraction increased when cells were nitrogen deficient but decreased in phosphate deficient cultures because a phosphate shortage inhibited respiration more severely than photosynthesis.Gross photosynthesis at low light intensities was proportional to the total number of molecules of all plant pigments added together, irrespective of species or of culturing conditions. By contrast, the rate of maximum gross photosynthesis was poorly related to pigment composition, the best correspondence being with the amount of chlorophyll a in the cultures.The uptake rate of C-14 varied with time. There was an apparent "leakage" of labelled organic matter which eventually reached a near-equilibrium with 14CO2 uptake, after which the C-14 method measured the production of particulate carbon but not necessarily net or gross photosynthesis. The rate of particulate carbon production was the same as that of cell division but about 40% less than net photosynthesis in cultures of Skeletonema. Agreement between C-14 rates and net photosynthesis was better in cool-white fluorescent light than in the imitation submarine sunlight used in this work. At high light intensities there was apparently no excretion from Dunaliella "shade" cells but when these became changed to "sun" cells they behaved more like Skeletonema.Various observations are recorded of the effect of growth conditions on cell composition, especially with regard to pigments.The relatively low C-14 rates found with Skeletonema costatum may be explicable in part by an abnormally low counting efficiency for this species even when present as a "weightless" source but the problem requires further study.

Studies on the Factors Affecting the Release of Organic Matter By Skeletonema Costatum (Greville) Cleve in Culture

1973 ◽  
Vol 53 (4) ◽  
pp. 937-956 ◽  
Author(s):  
L. Ignatiades ◽  
G. E. Fogg
Keyword(s):  
Organic Matter ◽  
Skeletonema Costatum ◽  
Physiological Activity ◽  
Marine Phytoplankton ◽  
Low Light ◽  
Factors Affecting ◽  
Light Intensities

A few studies on the excretion of organic matter by marine phytoplankton in culture have been reported (Guillard & Wangersky, 1958; Wangersky & Guillard, 1960; Stewart, 1963; Hellebust, 1965). Eppley & Sloan (1965) reported extensive excretion in Skeletonema costatum (Greville) Cleve cultures as they approached senescence and emphasized that excretion is inversely proportional to the physiological activity of cells. Hellebust (1965) demonstrated the release of high amounts (up to 38% of the carbon assimilated) of organic matter by Sk. costatum cells exposed to low light intensities. It is apparent that more knowledge is needed in order to define the intra- and extracellular factors affecting the excretion.

Theoretical and Experimental Analysis of the 14C Technique and Its Use in Studies of Primary Production

1976 ◽  
Vol 33 (8) ◽  
pp. 1715-1721 ◽  
Author(s):  
Louis A. Hobson ◽  
W. James Morris ◽  
Kathleen T. Pirquet
Keyword(s):  
Environmental Conditions ◽  
Experimental Analysis ◽  
Rate Constants ◽  
Net Photosynthesis ◽  
Field Studies ◽  
Marine Phytoplankton ◽  
Theoretical Studies ◽  
Continuous Irradiation ◽  
Gross Photosynthesis ◽  
Photosynthesis And Respiration

Theoretical and experimental field studies of 14C uptake by marine phytoplankton were carried out to determine environmental conditions required for the technique to measure net photosynthesis. Results of theoretical studies indicate that rapidly metabolizing populations (rate constants for gross photosynthesis and respiration of 0.1 h−1 and 0.007 h−1 respectively) may saturate with 14C after about 30 h of continuous irradiation. Results of field studies indicate that a minimum of 24 h are required for net photosynthesis to be measured when daily irradiations exceed 20 cal cm−2 and nutrient limitation of photosynthesis does not occur. Additional measurements that may be made to aid in interpreting results obtained by the 14C technique are briefly discussed.

The Clogging of Sewage Lagoon Aerators

1989 ◽  
Vol 21 (6-7) ◽  
pp. 669-676
Author(s):  
E. Davis
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Algal Growth ◽  
Growth Conditions ◽  
Field Investigation ◽  
Large Bubble ◽  
Physical Factors ◽  
Pull System ◽  
Fine Bubble

The Lagoon method of waste water treatment was introduced into Canada in the mid 1950's. At present, of the 2019 waste water treatment systems in Canada, 1163 are Lagoon systems and 265 of these include aeration equipment. Continuing difficulties associated with the plugging of the aerators have led to a study of this maintenance problem. Physical factors have been identified as the major cause of the plugging of large bubble aerators; whereas chemical solution and deposition under high algal growth conditions have been set forward as the causes of fine bubble aerator plugging. Selected field investigation data collected indicate that the proposed push-pull system of precipitation of calcium carbonate and silica dioxide may in fact be responsible for the plugging of fine bubble aerators with these materials.

Airborne Algal growth on roofs of membrane-structured residences in cold area of Japan

2020 ◽  
pp. 174425912098003
Author(s):  
Makiko Nakajima ◽  
Daisuke Masueda ◽  
Shuichi Hokoi ◽  
Takayuki Matsushita
Keyword(s):  
Algal Growth ◽  
Residential Building ◽  
Growth Conditions ◽  
Building Structure ◽  
Transparent Film ◽  
Cold Region ◽  
Algal Population ◽  
Building Facades ◽  
Cold Area ◽  
Survey Results

The discoloration of building facades due to airborne algae is observed in our surroundings. The growth conditions of these algae are not yet fully understood, and efficient measures for preventing the growth of the algae are not presently available. The objective of this study was to investigate the effects of the ambient environment and building structure on algal growth. A residential building in a cold region of Japan was surveyed. The roof was a multi-layered structure comprising a semi-transparent film, an air layer, and a layer of insulation from the outside, supported by rafters. The soiled state was visually observed by taking photographs. On the northeast (NE) and northwest (NW) roofs, several black stripes appeared 4 months after cleaning. The soiling increased in the spring and autumn. The soiling first appeared on the film backed by the rafter and then extended to the film backed by the air layer. The condensation time during the day in the rafter part was longer than that in the air-layer part. Condensation occurred during the night, but its frequency exhibited no dependence on the orientation of the roof. Algae tend to die when exposed to an environment with a temperature higher than 45°C. The NE roof had the shortest period with a surface temperature of >45°C. These measurements agreed well with the survey results, which indicated that the soiling mainly occurred on the NE and NW sides of the roofs. The time for algal growth was estimated under the assumption that algae can grow at surface temperatures ranging from 0 to 45°C, in agreement with the observed soiling. The observed soiling changes were well explained by the algal population calculated via a growth predictive model according to the algal temperature and relative humidity.

Carbon dioxide transfer resistance as a factor in shade tolerance of tree seedlings

1970 ◽  
Vol 48 (3) ◽  
pp. 453-456 ◽  
Author(s):  
J. E. Wuenscher ◽  
T. T. Kozlowski
Keyword(s):  
Carbon Dioxide ◽  
Acer Saccharum ◽  
Net Photosynthesis ◽  
Tree Seedlings ◽  
Transfer Resistance ◽  
Quercus Velutina ◽  
Light Intensities ◽  
Quercus Species ◽  
Highly Correlated ◽  
Resistance Rates

Net photosynthesis and transpiration rates of single leaves of Quercus velutina Lam., Q. macrocarpa Michx. var. olivaeformis, and Acer saccharum Marsh. were measured at light intensities of 0.03 to 0.24 cal cm−2 min−1 (400–700 mμ). Resistance to water vapor and carbon dioxide transfer were calculated. Net photosynthesis of the Quercus species was not light saturated until light intensity was increased sufficiently to induce complete stomatal opening, indicating possible limitation of CO2 uptake at low light intensities by high CO2 transfer resistance. Rates of light-saturated net photosynthesis of all three species were highly correlated with CO2 transfer resistance.

Pycnidium production by Botryodiplodia theobromae. I. The relation of light to the induction of pycnidia

1969 ◽  
Vol 47 (7) ◽  
pp. 1153-1156 ◽  
Author(s):  
J. A. Ekundayo ◽  
R. H. Haskins
Keyword(s):  
Light Intensity ◽  
Ultraviolet Radiation ◽  
Exposure Period ◽  
Fluorescent Light ◽  
Botryodiplodia Theobromae ◽  
Continuous Irradiation ◽  
Long Wave ◽  
Light Intensities ◽  
Glass Color ◽  
Color Filters

Cultures of Botryodiplodia theobromae Pat. produced pycnidia abundantly on several media under continuous irradiation with fluorescent light. The fungus did not sporulate when grown in darkness. Irradiation of cultures with a light intensity of 15 foot-candles for 4 days was sufficient to stimulate pycnidial production, but for appreciable sporulation to occur over the same exposure period, higher light intensities are required. Irradiation of cultures through glass color filters showed that long-wave ultraviolet radiation stimulated sporulation.

scholarly journals A model for variable phytoplankton stoichiometry based on cell protein regulation

2013 ◽  
Vol 10 (2) ◽  
pp. 3241-3279
Author(s):  
J. A. Bonachela ◽  
S. D. Allison ◽  
A. C. Martiny ◽  
S. A. Levin
Keyword(s):  
Physiological State ◽  
Single Point ◽  
Nutrient Content ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Cell Protein ◽  
Nitrogen And Phosphorus ◽  
Elemental Ratios ◽  
Regulatory Processes ◽  
Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

scholarly journals EslB is required for cell wall biosynthesis and modification in Listeria monocytogenes

2020 ◽  
Author(s):  
Jeanine Rismondo ◽  
Lisa M. Schulz ◽  
Maria Yacoub ◽  
Ashima Wadhawan ◽  
Michael Hoppert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Listeria Monocytogenes ◽  
Abc Transporter ◽  
Cell Lysis ◽  
Growth Conditions ◽  
Cell Wall Integrity ◽  
Growth Defect ◽  
Cell Wall Biosynthesis ◽  
High Concentrations

Lysozyme is an important component of the innate immune system. It functions by hydrolysing the peptidoglycan (PG) layer of bacteria. The human pathogen Listeria monocytogenes is intrinsically lysozyme resistant. The peptidoglycan N-deacetylase PgdA and O-acetyltransferase OatA are two known factors contributing to its lysozyme resistance. Furthermore, it was shown that the absence of components of an ABC transporter, here referred to as EslABC, leads to reduced lysozyme resistance. How its activity is linked to lysozyme resistance is still unknown. To investigate this further, a strain with a deletion in eslB, coding for a membrane component of the ABC transporter, was constructed in L. monocytogenes strain 10403S. The eslB mutant showed a 40-fold reduction in the minimal inhibitory concentration to lysozyme. Analysis of the PG structure revealed that the eslB mutant produced PG with reduced levels of O-acetylation. Using growth and autolysis assays, we show that the absence of EslB manifests in a growth defect in media containing high concentrations of sugars and increased endogenous cell lysis. A thinner PG layer produced by the eslB mutant under these growth conditions might explain these phenotypes. Furthermore, the eslB mutant had a noticeable cell division defect and formed elongated cells. Microscopy analysis revealed that an early cell division protein still localized in the eslB mutant indicating that a downstream process is perturbed. Based on our results, we hypothesize that EslB affects the biosynthesis and modification of the cell wall in L. monocytogenes and is thus important for the maintenance of cell wall integrity. IMPORTANCE The ABC transporter EslABC is associated with the intrinsic lysozyme resistance of Listeria monocytogenes. However, the exact role of the transporter in this process and in the physiology of L. monocytogenes is unknown. Using different assays to characterize an eslB deletion strain, we found that the absence of EslB not only affects lysozyme resistance, but also endogenous cell lysis, cell wall biosynthesis, cell division and the ability of the bacterium to grow in media containing high concentrations of sugars. Our results indicate that EslB is by a yet unknown mechanism an important determinant for cell wall integrity in L. monocytogenes.

scholarly journals Fast growth conditions uncouple the final stages of chromosome segregation and cell division in Escherichia coli

PLoS Genetics ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. e1006702 ◽  
Author(s):  
Elisa Galli ◽  
Caroline Midonet ◽  
Evelyne Paly ◽  
François-Xavier Barre
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Chromosome Segregation ◽  
Growth Conditions ◽  
Fast Growth
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