An algal cyclostat with computer-controlled dynamic light regime

Kroon, Bernd M. A.; Hes, Udo M. van; Mur, Luuc R.

doi:10.1007/978-94-011-2805-6_4

Cited by 11 publications

(12 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The green microalga Chlorella pyrenoidosa was used as test organism and was cultured in 2.2 1 continuous cultures (Kroon et al, 1992a). Three cultures were used, each which received a different diurnal light regime, but the same dilution rate of 0.7 day-1.…”

Section: Methodsmentioning

confidence: 99%

“…Culture 2 had a block light curve, where the lights were switched on at the beginning of the light period and switched off at the end of it. Culture 3 received an overall sinusoidal light pattern during the light period with hourly oscillations superimposed on it (Kroon et al, 1992a). The total light doses (PAR) for the block, sinusoidal and oscillating patterns were 8.20, 10.73 and 11.83 mol m-2 d-1, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Light/dark cycles of equal duration are common in nature, especially in waters with wave action. Additional informa-tion on the cultures used and photosynthesisirradiance parameters are given in Kroon et al (1992a, b).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of medium frequency light/dark cycles of equal duration on the photosynthesis and respiration of Chlorella pyrenoidosa

et al. 1992

Self Cite

View full text Add to dashboard Cite

Chlorellapyrenoidosa was grown in three continuous cultures each receiving a different light regime during the light period of a diurnal cycle. Hourly samples taken during the light period were subjected to medium frequency light/dark oscillations of equal duration, ranging from 3 to 240 seconds. The oxygen consumption and production of each sample were measured with an oxygen electrode in a small oxygen chamber. Although the light/dark cycles had little overall influence on photosynthetic activity, the microalgae appeared to adapt to the light regime to which they were subjected. Large differences were found between the maximum chlorophyll-specific production rates (POax), the chlorophyll-specific production rates (pB) and the respiration rates between the cultures and treated subsamples. Respiration rates increased during the light period, whilst pB either increased, or had a mid light period minimum or maximum. The culture which received an hourly light oscillation during the light period had the highest Pmax and lowest respiration rates, and it is suggested that these algae react as in nature, whereas either a sinusoidal or a block light pattern is 'unnatural'. The latter light regime is commonly used in laboratory studies.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of medium frequency light/dark cycles of equal duration on the photosynthesis and respiration of Chlorella pyrenoidosa

et al. 1992

Self Cite

View full text Add to dashboard Cite

show abstract

“…The vessels were temperature controlled and gently aerated to keep Microcystis in suspension. Changes in light intensity were computer controlled by a venetian blind (Kroon et al 1992). We assume that the growth rate of Microcystis is proportional to its carbon assimilation rate.…”

Section: Impact Of Light and Temperature On Growth Ratementioning

confidence: 99%

Water Management Strategies Against Toxic Microcystis Blooms In The Dutch Delta

Verspagen

Passarge

Joehnk

et al. 2006

Ecological Applications

112

100

View full text Add to dashboard Cite

Abstract. To prevent flooding of the Dutch delta, former estuaries have been impounded by the building of dams and sluices. Some of these water bodies, however, experience major ecological problems. One of the problem areas is the former Volkerak estuary that was turned into a freshwater lake in 1987. From the early 1990s onward, toxic Microcystis blooms dominate the phytoplankton of the lake every summer. Two management strategies have been suggested to suppress these harmful algal blooms: flushing the lake with fresh water or reintroducing saline water into the lake. This study aims at an advance assessment of these strategies through the development of a mechanistic model of the population dynamics of Microcystis. To calibrate the model, we monitored the benthic and pelagic Microcystis populations in the lake during two years. Field samples of Microcystis were incubated in the laboratory to estimate growth and mortality rates as functions of light, temperature, and salinity. Recruitment and sedimentation rates were measured in the lake, using traps, to quantify benthic-pelagic coupling of the Microcystis populations. The model predicts that flushing with fresh water will suppress Microcystis blooms when the current flushing rate is sufficiently increased. Furthermore, the inlet of saline water will suppress Microcystis blooms for salinities exceeding 14 g/L. Both management options are technically feasible. Our study illustrates that quantitative ecological knowledge can be a helpful tool guiding large-scale water management.

show abstract

“…Figure 1 shows the variation in PPFD for the three regimes. The 10 h light period started at 08.00 h local time, and lasted till 18.00 h. Values of the total daily light dose (TDLD) were calculated as described in Kroon et al (1992a), and can be found in Table 1 of significant differences was based on the 95 % confidence levels; the number of degrees of freedom was six for Z^ = 0, and 12 for Z^j = 0-7 Z^,,, and Z,,, = 2 Z»,,.…”

Section: Light Regimesmentioning

confidence: 99%

Acclimation of photosystem II in a cyanobacterium and a eukaryotic green alga to high and fluctuating photosynthetic photon flux densities, simulating light regimes induced by mixing in lakes

1994

Self Cite

View full text Add to dashboard Cite

SUMMARYPhotoacclimation of Scenedesmus protuberans F'ritsch and Microcystis aeruginosa Kutzing emend. Elenkin to high and fluctuating PPFD was studied in continuous cultures with computer-controlled variable light regimes. The aim of the work was to provide a better understanding of species-specific acclimation to high PPFD (as encountered by cyanobacteria in surface waterblooms), and of suppression of the growth of colony-forming cyanobacteria during periods of prolonged mixing in lakes. The dynamics of a set of variables was followed during the light period, including pigment composition, maximum rate, efficiency and minimum quantum requirement of photosynthesis, PS 11 cross-sections, and fluorescence variables. Both the green alga and the cyanobacterium displayed strong photo-inhibition of photosynthesis in the sinusoidal light regime, which simulated a natural light regime in the absence of mixing. P,,,,,^, a, QR and the ratio of variable to maximum fluorescence declined, and the number of inactive PS II centres and PS II,, centres increased towards midday. Introduction of oscillations in the diurnal light regime, simulating different intensities of wind-induced mixing in lakes, mitigated photo-inhibition. Microcystis showed a prompt non-photochemical quenching of fluorescence in all light regimes, even at low to moderate PPFD. The sustained presence of zeaxanthin in Microcystis possibly induced instant, thermal dissipation of excitation energy from the antenna. Microcyslis also exhibited a more reluctant acclimation to fluctuating PPFD. Growth rate of Scenedesmus was higher in all light regimes. This implied that if (known) differences in loss processes were ignored, Scenedesmus would outcompete Microcystis in lakes. Tbe results underlined the importance of buoyancy regulation in increasing the daily light dose of cyanobacteria (but at the same time preventing over-excitation), and ultimately in tbe success in Microcystis in stable lakes.

show abstract

An algal cyclostat with computer-controlled dynamic light regime

Cited by 11 publications

References 10 publications

Influence of medium frequency light/dark cycles of equal duration on the photosynthesis and respiration of Chlorella pyrenoidosa

Influence of medium frequency light/dark cycles of equal duration on the photosynthesis and respiration of Chlorella pyrenoidosa

Water Management Strategies Against Toxic Microcystis Blooms In The Dutch Delta

Acclimation of photosystem II in a cyanobacterium and a eukaryotic green alga to high and fluctuating photosynthetic photon flux densities, simulating light regimes induced by mixing in lakes

Contact Info

Product

Resources

About