Photoperiod and light intensity effects on growth and utilization of nutrients by the aquaculture feed microalga, Tetraselmis chui (PLY429 (original) (raw)
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Aquaculture, 2005
Light intensity, day length, and nutrient concentrations are important factors regulating the growth of phytoplankton. To reduce culturing costs, natural sunlight and greenhouses can be used to minimize the amount of artificial light needed for algal growth. However, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment. This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (strain PLY429)-an algal strain used widely as an aquaculture feed. PLY429 was grown aseptically for 28 days under three different light intensities (220, 110, and 73 AEinst. m À2 s À1 ) and four different light:dark cycles (24:0, 16:8; 12:12; 8:16). Growth and net nutrient-uptake rates for PLY429 were calculated for each treatment. Longer day length and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities. PLY429 cultures that were exposed to only 8 h of light had the slowest growth and utilization of nutrients. These findings suggest that day length is important in determining growth and nutrient uptake in PLY429; at a latitude of 418N, artificial light will need to be added to algal cultures in a greenhouse to increase both day length and total daily light input. D
Phytoplankton growth and light absorption as regulated by light, temperature, and nutrients
Polar Research, 1991
Numerous studies of the growth of phytoplankton in the laboratory have demonstrated the dependence of cellular pigment concentration and growth rate upon light intensity. photoperiod, temperature, and nutrient supply. These same environmental parameters vary with season in the polar seas and presumably affect the growth rate and cellular pigment concentration of the phytoplankton crop. Unfortunately, there has not been a complete mathematical description of the interaction of all four environmental parameters. This study presents an approach to describing these interactions. It can reasonably be assumed that the gross specific growth rate. g. is a function of the specific rate of light absorption: g = n r (1-exp(-a, m., Eo/n 8)). The dependent variables in this equation arc g, the gross specific growth rate, n. the maximum carbonspecific photosynthetic rate, and, 8, the ratio of carbon to chlorophyll. The value of all three dependent variables is constrained. The independent variables are E 0 • the light intensity (assumed constant during the photoperiod), and r. the photoperiod (as a fraction of 24 hours) that the cells arc illuminated. n is the instantaneous capacity of the dark reactions to assimilate electrons. while the product ar m,, E 11 / 8 is the instantaneous capacity of the light reactions to supply electrons. If the capacity for photochemistry exceeds the capacity for assimilation. dissipative processes occur. and the quantum yield is low. We have applied this equation to the analysis of the growth and light absorption by Skeletonema costatwn cultured under light, temperature. and nutrient limitation. Decreases in nutrient supply and temperature cause decreases in n and increases in 6; thus both the capacity for electron supply and utilisation decrease. However, decreases in temperature decrease the capacity for electron assimilation more rapidly than the capacity for supply; quantum yield drops. Decreases in nutrient supply cause the capacity for supply and assimilation to drop in parallel; quantum yeicld is maintained. Decreases in day length cause decreases in 8 and increases in n. The capacity to assimilate electrons and the capacity to supply electrons increase in parallel; quantum yield is maintained. Decreases in light intensity cause decreases in both 8 and the capacity to supply electrons. Although the changes in n with light intensity arc difficult to assess. the capacity to assimilate electrons appears to be little changed by light limitation. Quantum yields increase with decreasing light levels.
Continuous culture of the marine microalga Tetraselmis sp. — productivity analysis
Aquaculture, 1990
An outdoor experimental system for continuous culture of the marine microalga Tetraselmis sp. is described. The influence of dilution rate, initial biomass concentration and the intensity of solar radiation on the amount of biomass obtained was examined. The average rate of production of cells, G,. is a parabolic function of the dilution rate and reached a maximum value at D=O.O9 h-'. The intensity of light, I,, influences productivity up to approximately 100 W/m*, above which saturation was observed. The experimental results G,-I, were adjusted to an exponential model for light-restricted growth. The average rate of production of cells, versus the initial biomass concentration, C,, reached a maximum value. G,,, decreased as C,, increased to high cell density values due to light limitation and when C, decreased to low cell density values due to decreased efficiency in the use of incident solar radiation.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2009
Effects of Light intensity of 100 and 150 Jlmol.photon.m• 2 .s• 1 in dark: light periods of8:16, 12:12, and 16:8 hours on growth rate and lipid synthesis in a green algae Dunaliella salina were studied. Algae was cultured and required treatments were applied. Algae cells were counted regularly daily bases using Thoma counting chamber and specific growth rate was calculated. Lipid synthesis also was measured in all treatments. Specific growth rate and lipid synthesis showed significant differences in various light treatments (P<0.05). The maximum specific growth rate was 4.1 d-1 in 12:12 hours light: dark treatment under 150 Jlmol.photon.m• 2 _s• 1 and the minimum growth was 0.8 d-1 in 8:16 light: dark condition under 100 Jlmol.photon.m• 2 .s• 1 light intensity. The maximum lipid synthesis was 14.1% in 16: 8 hours light: dark treatment under 100 Jlmol. photon. m• 2 .s• 1 and the minimum was 2.2% in 12:12 hours of light: dark condition under 150 Jlmol.photon.m• 2 .s• 1 light intensity. The obtained results shows that environmental factors such as light intensity, photoperiod influence the growth and lipid synthesis in green algae Dunaliella salina. Under stress condition lipid synthesis is increased. Increase in growth rate does not necessarily reflects increase in biochemical components of algae.
Growth Rates of Marine Phytoplankton: Correlation with Light Absorption by Cell Chlorophyll a
Physiologia Plantarum, 1966
To better predict plant production in the sea, it would be desirable to be able to calculate, from easily obtainable measurements at one sampling, the growth rate of the prevailing stock of phytoplankton. To this end growth rates, pigment composition, cell volume and cell surface area data were collected for several species of marine phytoplankton in logarithmic growth at 20–21°C and 0.07 cal/cm2. min light intensity. Similar data for one species, Dunaliella tertiolecta, are given for several combinations of light intensity and temperature, and for another species, Ditylum brightwellii, grown in nitrogen deficiency.The problem of estimating growth rates of phytoplankton was divided into three parts: 1) variation of growth rate among diverse species and its relationship to light absorption by cell chlorophyll a: 2) variation in growth rate with light intensity; 3) variation in growth rate with temperature. An equation has been formulated for calculating growth rate which provides a m...
Latin American Journal of Aquatic Research, 2021
Tetraselmis suecica is a green microalga that thrives under a wide range of conditions, used in the commercial culture of fish, mollusk, and crustacean larvae for supplementing the demand for fertilizers. Its pigments have applications in human health care as drug products, vitamins, and cosmetics. Growth and pigment concentration of T. suecica were evaluated in experimental cultures with different nutrient concentrations and light intensities to determine the most appropriate culture conditions to optimize the production of biomass and pigments. Chlorophyll-a, chlorophyll-b, lutein, violaxanthin, α, β-carotene, and neoxanthin concentrations were evaluated under three different nutrient conditions (441.5/18.1, 883/36.3, and 1766/76.2 μM of NaNO3/NaH2PO4) and four light intensities (50, 150, 300, and 750 μmol quanta m-2 s-1). Increases in either or both of these factors lead to increases in the concentration of all pigments. Chlorophyll-a reached up to 5×103 mg m-3, chlorophyll-b up ...
Influence of photoperiods on the growth rate and biomass productivity of green microalgae
Bioprocess and Biosystems Engineering, 2014
The effect of different photoperiods: 24 h illumination and a 12:12-h light/dark (12L:12D) cycle on the growth rate and biomass productivity was studied in five algal species: Neochloris conjuncta, Neochloris terrestris, Neochloris texensis, Botryococcus braunii and Scenedesmus obliquus. The green microalgae examined differ in the reproduction mode. Continuous illumination stimulated the growth of B. braunii and S. obliquus more effectively than the growth of the microalgal species from the genus Neochloris. However, under shorter duration of light of the same intensity (12L:12D cycle), the growth of all the three species of Neochloris was stimulated. Under continuous illumination, the specific growth rate in the first phase of B. braunii and S. obliquus cultures was higher than the growth rate of Neochloris, whereas under the 12L:12D cycle, the specific growth rate of all the three Neochloris species was generally higher than that in B. braunii and S. obliquus. As a result, the light regime influenced algal biomass productivity differently. The maximum biomass productivity was obtained in B. braunii and S. obliquus cultures carried out at continuous illumination. All the Neochloris species produced biomass more efficiently at the 12L:12D cycle, which was two-threefold higher than that of B. braunii and S. obliquus. The unicellular species of the green microalgae from the genus Neochloris, examined for the first time in this study, are promising prospective objects for algal biotechnology.
Effects of nutrient and light limitation on the biochemical composition of phytoplankton
Journal of Applied Phycology, 1990
Three marine phytoplankters (Isochrysis galbana, Chaetoceros calcitrans and Thalassiosira pseudonana), commonly used in the culture of bivalve larvae, were grown in batch or semi-continuous cultures. Changes in protein, carbohydrate, lipid and some fatty acids were measured as growth became limited by nitrogen, silicon, phosphorus or light. Under N starvation (2 d) the % lipid remained relatively constant, while% carbohydrate increased and% protein decreased in all 3 species compared to cells growing under no nutrient limitation. Under Si starvation (6 h) there was no change in lipid, protein or carbohydrates. The amount of two fatty acids, 20: 5o3 and 22: 6co3 remained relatively constant under N, P and Si starvation, exept for a sharp drop in the cells of P-starved T. pseudonana. However, there were pronounced species differences with I. galbana containing significantly less 20: 5 co3 than C. calcitrans or T. pseudonana. Under light limitation the amount of lipid per cell showed no consistent trend over a range of irradiances for all 3 species. The amount of N per cell (an index of protein content) as a function of irradiance, was relatively constant for I. galbana and T. pseudonana, while the amount of N per cell was lower under low irradiances for C. calcitrans. These examples of changes in protein, carbohydrate, lipid and certain fatty acids under nutrient (N, Si or P) or light limitation, emphasize the importance of knowing the phase (e.g. logarithmic vs stationary) of the growth curve in batch cultures, since the nutritional value of the phytoplankters could change as cultures become dense and growth is terminated due to nutrient or light limitation.