Photosynthetic rates of benthic marine algae in relation to light intensity and seasonal variations

1976 ◽  
Vol 37 (3) ◽  
pp. 215-222 ◽  
Author(s):  
R. J. King ◽  
W. Schramm
Keyword(s):  
Light Intensity ◽  
Seasonal Variations ◽  
Marine Algae ◽  
Photosynthetic Rates

Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms

1976 ◽  
Vol 6 (1) ◽  
pp. 40-48 ◽  
Author(s):  
R. A. Keller ◽  
E. B. Tregunna
Keyword(s):  
Light Intensity ◽  
Water Content ◽  
Water Vapour ◽  
Western Hemlock ◽  
Diffusion Resistance ◽  
The Sun ◽  
Evaporative Demand ◽  
Photosynthetic Rates ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.

Experimental observations on variability of leaf and air vesicle shape of Sargassum muticum

1983 ◽  
Vol 63 (4) ◽  
pp. 825-831 ◽  
Author(s):  
Alan T. Critchley
Keyword(s):  
Light Intensity ◽  
Plant Growth ◽  
Seasonal Variations ◽  
Leaf Shape ◽  
Taxonomic Status ◽  
Culture Conditions ◽  
Sargassum Muticum ◽  
Vesicle Shape ◽  
Large Genus ◽  
Laboratory Investigations

Seasonal variations in the range of air vesicle and leaf shape upon the brown alga Sargassum muticum (Yendo) Fensholt provide some discrepancies with descriptions of material from the alga's indigenous Japanese and introduced British Columbian habitats.Experimental observations indicate that mucronate air vesicles are most common at low (i.e. 10 °C) and high (i.e. 25 °C) temperatures, with those of 30 °C being injurious to plant growth. Air vesicles with spiked proliferations are also seen to increase in occurrence with an increasing light intensity at 20 °C. Excised ‘winter’ form leaves collected in February were able to regenerate ‘summer’ form leaves from their damaged bases, under culture conditions.Field and laboratory investigations show that leaf and air vesicle shape tend to vary seasonally and may be experimentally changed by both temperature and light intensity. Such plasticity observed in the morphology of these characters in S. muticum raises doubts as to the taxonomic status of many species ascribed to the large genus Sargassum.

Photosynthetic apparatus in Selaginella. I. Morphology and photosynthesis under different light and temperature regimes

1970 ◽  
Vol 48 (10) ◽  
pp. 1843-1852 ◽  
Author(s):  
Richard Jagels
Keyword(s):  
Light Intensity ◽  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Photosynthetic Rates ◽  
Sterile Culture ◽  
Light Levels ◽  
Light Intensities ◽  
Temperature Regimes ◽  
Normal Green ◽  
Branching Patterns

Several hydrophytic and umbrophilic species of Selaginella were grown in sterile culture and scrutinized for morphological and photosynthetic variability under light intensities between 0 and 500 ft-c and temperatures of 9° and 22 °C. Bleaching was induced by raising light intensity; and for a particular light intensity was enhanced by lowering temperature. Regreening could be achieved by reversing conditions. Branching patterns, leaf symmetry, and orientation of leaves to axis were also light dependent. Light levels which produced normal green plants for S. uncinata initiated only half-saturation photosynthetic rates. Photosaturating light intensities, if applied for several weeks, induced bleaching. Based on fresh or dry weight bleaching plants had lower photosynthetic rates than green plant's; but based on chlorophyll content the photosynthetic rates of green and bleaching plants were the same.

Light intensity, photoperiod duration, daily light flux and coral growth of Galaxea fascicularis in an aquarium setting: a matter of photons?

2011 ◽  
Vol 92 (4) ◽  
pp. 703-712 ◽  
Author(s):  
Miriam Schutter ◽  
Rosa M. van der Ven ◽  
Max Janse ◽  
Johan A.J. Verreth ◽  
René H. Wijffels ◽  
...  
Keyword(s):  
Light Intensity ◽  
Growth Rates ◽  
Abiotic Factors ◽  
Light Flux ◽  
Light Treatment ◽  
Coral Growth ◽  
Dark Cycle ◽  
Photosynthetic Rates ◽  
Galaxea Fascicularis ◽  
Light Duration

Light is one of the most important abiotic factors influencing the (skeletal) growth of scleractinian corals. Light stimulates coral growth by the process of light-enhanced calcification, which is mediated by zooxanthellar photosynthesis. However, the quantity of light that is available for daily coral growth is not only determined by light intensity (i.e. irradiance), but also by photoperiod (i.e. the light duration time). Understanding and optimizing conditions for coral growth is essential for sustainable coral aquaculture. Therefore, in this study, the question was explored whether more light (i.e. more photons), presented either as irradiance or as light duration, would result in more growth. A series of nine genetically identical coral colonies of Galaxea fascicularis L. were cultured for a period of 18 weeks at different light duration times (8 hours 150 μE m−2 s−1:16 hours dark, 12 hours 150 μE m−2 s−1:12 hours dark, 16 hours 150 μE m−2 s−1:8 hours dark, 24 hours 150 μE m−2 s−1:0 hours dark) and different irradiance levels (8 hours 150 μE m−2 s−1:16 hours dark, 8 hours 225 μE m−2 s−1:16 hours dark and 8 hours 300 μE m−2 s−1:16 hours dark). Growth was determined every two weeks by measuring buoyant weight. Temperature, salinity and feeding levels were kept constant during the experiment. To detect possible acclimation of the corals to an increased light duration, rates of net photosynthesis and dark respiration were measured, hereby comparing coral colonies grown under an 8:16 hours light (150 μE m−2 s−1):dark cycle with corals grown under a 16:8 hours light (150 μE m−2 s−1):dark cycle. No increase in growth was detected with either increasing photoperiod or irradiance. Continuous lighting (24 hours 150 μE m−2 s−1:0 hours dark) resulted in immediate bleaching and the corals died after 14 weeks. Hourly photosynthetic rates were significantly reduced in the 16 hour light treatment compared to the 8 hour light treatment. As a result, daily net photosynthetic rates were not significantly different, which may explain the observed specific growth rates. Acclimation to photoperiod duration appeared neither to be mediated by changes in chlorophyll-a concentration nor zooxanthellae density. Based on the results of this study, we can conclude that the enhancing effect of light on coral growth is not only a matter of photons. Obviously, the availability of light was not limiting growth in these experiments and was probably in excess (i.e. stressful amounts). Other factors are discussed that play a role in determining growth rates and might explain our results.

scholarly journals Studies of photo-synthesis in marine algæ.—1. Fixation of carbon and nitrogen from inorganic sources in sea water. 2. Increase of alkalinity of sea water as a measure of photo-synthesis

1921 ◽  
Vol 92 (642) ◽  
pp. 51-60 ◽  
Keyword(s):  
Seasonal Variation ◽  
Cell Division ◽  
Fresh Water ◽  
Seasonal Variations ◽  
Marine Algae ◽  
Sea Water ◽  
Subsequent Paper ◽  
Carbon And Nitrogen ◽  
Applied Physiology ◽  
Series Of Experiments

The series of experiments recorded in this communication were carried out at Port Erin; the subsequent analyses for amounts of nitrogen fixed were made at the temporary laboratory of the Department of Applied Physiology, M. R. C., at the Lister Institute. The results of the series confirm and amplify those obtained with fresh-water algæ, which showed a convincing uptake of nitrogen from the air, but on account of the change of the medium of growth from fresh to sea water, there are several important modifications in the medium itself as well as in the growing algæ, which appear to us to possess considerable importance in the annual life of the sea, and in the inductance at certain definite periods of the year of increased processes of cell-division and reproduction of species, and possibly in guiding the development of variations in species, and the process of evolution. The details of seasonal variation in growth resulting from intensity of illumination will be given in a subsequent paper; here will be considered the changes in the algæ and the sea water due to the action of light apart from seasonal variations.

scholarly journals Biological Hydrogen Production from Amphora sp. Isolated from Eastern Coast of Thailand

2019 ◽  
Vol 93 ◽  
pp. 03004
Author(s):  
W Jangiam ◽  
P Tongtubtim ◽  
M Penjun
Keyword(s):  
Hydrogen Production ◽  
Light Intensity ◽  
Fossil Fuels ◽  
Marine Algae ◽  
Average Rate ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Eastern Coast ◽  
The World ◽  
Many Sources

The world is finding ways of producing fuel from many sources to replace the fossil fuels. Hydrogen is considered one of the most promising fuels for the future. One biological way of producing hydrogen from solar energy is using photosynthetic microorganisms.The objective of this study is to search for marine algae which produce hydrogen and study the appropriate conditions to produce hydrogen from marine algae. Firstly, the 5 strains of algae were studied the total gas production. Amphora sp. was selected and studied the appropriate conditions to produce hydrogen gas. The first condition, we studied the important factors for marine algae which were present and absent sulfur. The second condition was to find the suitable pH for producing hydrogen which were pH 7, pH 8 and pH 9. The last condition, we studied the optimal light intensity which were 481, 1075 and 2085 lux. The result showed that Amphora sp. can produce hydrogen gas in present sulfur media, pH 8 and light intensity 2085 lux in volume 495.3 ml per 1 L of algae or the average rate of produce hydrogen is 0.798 ml per g of algae per hour.

Chlorophyll a and c in Cultures of Marine Algae

1963 ◽  
Vol 14 (2) ◽  
pp. 148 ◽  
Author(s):  
GF Humphrey
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Growth Phase ◽  
Marine Algae ◽  
Skeletonema Costatum ◽  
Natural Populations ◽  
Initial Growth ◽  
Cell Numbers ◽  
Maximum Cell ◽  
Effect Of Light

Gymnodinium, Nitzschia closterium, and Skeletonema costatum were grown in the presence of bacteria, and N. closterium in the absence of bacteria, for 7 weeks. Each week samples were analysed by the Richards-Thompson method for chlorophyll a and c. Maximum cell numbers were reached in 1-3 weeks. Gymnodinium grew better at 680 f.c. than at 420 f.c. but the reverse was true of Nitzschia and Skeletonema. The chlorophyll content of the Gymnodinium cultures was similar at each light intensity but Nitzschia gave more chlorophyll at 420 f.c. With Skeletonema there was no consistent effect of light. During the initial growth phase, Gymnodinium contained 0.33-0.87 �g chlorophyll a and 0.56-1.88 pg chlorophyll c per million cells. The corresponding figures for Skeletonema were 0.03-0.06 and 0.03-0.08, and for Nitzschia 0.13-1.08 and 0.11-0.87. The ratio of c to a varied from 1.30 to 1.84 for Gymnodinium, 0.69 to 1 .61 for Skeletonema, and 0.44 to 2.21 for Nitzschia. These ratios are all less than the maximum (3.3) found for natural populations of phytoplankton from the Coral and Tasman Seas. There was no evidence in the culture experiments that chlorophyll c breaks down more slowly than a and thus accumulates in old populations.

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