Measurement and Interpretation of Photosynthetic Light‐response Curves in Algae in the Context of Photoinhibition and Diel Changes

This study investigated the influence of light on the distributional limits of Bostrychia scorpioides and Catenella caespitosa within a low amplitude intertidal zonation in the Palmones estuary, Spain. Changes in photosynthesis-and growth-irradiance curves and pigment content were examined ex situ at irradiances found in their natural habitat (10-230 µmol photons m −2 s −1). The highest maximum photosynthesis rate (P m ) and photosynthetic efficiency (α) were found between 20-40 µmol photons m −2 s −1 in both species. Bostrychia scorpioides, the uppermost intertidal species, had a higher P m , α, dark respiration rate and light compensation point (E c ) than C. caespitosa at all acclimation irradiances. Net photosynthetic rates measured at their respective acclimation irradiances showed photosynthetic responses of B. scorpioides to be maximized at high irradiances, while in C. caespitosa they did not change. Higher growth rates were obtained in C. caespitosa than in B. scorpioides, which may be related to its lower thallus specific carbon content. When irradiance decreased, the chlorophyll a content of B. scorpioides increased whereas in C. caespitosa R-phycoerythrin increased. E c for growth of B. scorpioides coincided with the irradiance at its lower distributional limit in the estuary, below which this species showed losses in biomass. However, in C. caespitosa the sustained growth ex situ at saturating irradiances contrasts with its absence from the upper intertidal zone, where similar light regimes occur. We demonstrated that while light clearly restricts the growth of B. scorpioides to the uppermost intertidal zone, this environmental factor would not prevent C. caespitosa from growing at higher levels.

show abstract

“…Light saturation point (E k ) was estimated as the ratio P m /α (Henley 1993). Oxygen evolution was expressed on a FW basis.…”

Section: Photosynthetic Measurementsmentioning

confidence: 99%

Understanding the intertidal zonation of two estuarine red macroalgae fromex situphotoacclimative responses

Pedro

Niell

Carmona

2014

European Journal of Phycology

View full text Add to dashboard Cite

show abstract

“…Growth rate is the outcome of many complex processes and although its relationship to irradiance and temperature can be modelled by mathematical equations this does not imply that growth is regulated by a single rate-determining reaction (Monod, 1949 ;Dawes, 1965). We chose the mathematical expression of Smith (1936) for its close correspondence with measured growth rates rather than for theoretical reasons (Jassby & Platt, 1976 ;Henley, 1993). For temperature effects we have insufficient information and have used a model (Q "! )…”

Section: mentioning

confidence: 99%

The daily integral of growth by Planktothrix rubescens calculated from growth rate in culture and irradiance in Lake Zürich

2000

View full text Add to dashboard Cite

In Lake Zu$ rich, populations of the cyanobacterium Planktothrix rubescens develop in the metalimnion during the summer and become gradually entrained in the deepening surface mixed layer during the autumn. It had previously been demonstrated that the daily integrals of photosynthetic production accounted for the growth observed in the metalimnion and greatly exceeded the smaller increase during the autumn. We have now determined the relationship between growth rate (µ) and irradiance (I ) in cultures of P. rubescens strain Pla 9316 maintained at 20mC on a 12 : 12 h light : dark cycle : the highest net growth rate averaged over the 24 h (µ h ) was 0.123 d −" , the dark rate (µ D ) was k0.020 d −" , the gross rate (φ m l µ h kµ D ) was 0.144 d −" , the affinity coefficient (α) was 0.0273 (d µmol m −# s −" ) −" and the compensation point (I C ) was 1.76 µmol m −# s −" . Using the corresponding coefficients calculated for the light period (µ Lh l 0.267 d −" , φ Lm l 0.287 d −" and α L l 0.0547 (d µmol m −# s −" ) −" ), instantaneous growth rates could be calculated from the irradiance. Comparison with growth rates at 10mC indicated a Q "! of 1.48. These coefficients were used in a modification of the Smith equation to calculate potential growth rates of Planktothrix from the irradiance and temperature at each time and depth in Lake Zu$ rich. Data on irradiance, vertical light attenuation and temperature were used to calculate the daily integrals of biomass increase over a period of 136 d. These growth integrals gave a closer correspondence to the observed population increase than the photosynthetic integrals calculated previously from measurements made with lakewater samples dominated by Planktothrix. Photosynthetic measurements made with the Planktothrix culture indicated a maximum rate of carbon increase (0.467 d −" ) that exceeds the maximum growth rate, which suggests that other factors limit growth over long periods.

show abstract

“…Each PPFR was supplied for 3 min and the rates of O # exchange were calculated from the linear increase or decrease in O # concentration. In order to minimize effects of photo inhibition (Henley, 1993), measurements were completed within 45 min.…”

Section: Photosynthesis\irradiance Responsementioning

confidence: 99%

“…the apparent quantum yield of O # production per unit of incident irradiance. In general, photosynthetic organisms respond to a decrease in the incident irradiance by increasing α (Henley, 1993). However, the physiological acclimation of the underlying photosynthetic machinery can vary, and organisms have been grouped according to characteristic changes in their P\I curves (Richardson, Beardall & Raven, 1983).…”

Section: Light-limited Growth Of Diazotrophsmentioning

confidence: 99%

Comparison of the light‐limited growth of the nitrogen‐fixing cyanobacteria Anabaena and Aphanizomenon

et al. 1998

View full text Add to dashboard Cite

The effect of simultaneous N # fixation and light limitation on the growth of two strains of Anabaena sp. Bory de St. Vincent and Aphanizomenon flos-aquae (L.) Ralfs was investigated using continuous cultures. Under severely light-limited conditions, Aphanizomenon showed a broader absorption spectrum (due to the presence of phycoerythrin), a higher maximum efficiency of photosynthesis, a higher steady-state N # fixation activity and a higher growth affinity for light than did Anabaena. On the other hand, under light saturation, Anabaena showed a higher maximum rate of O # production and a higher maximum specific growth rate than Aphanizomenon. These monoculture results characterize Anabaena and Aphanizomenon, in relative terms, as a ' sun ' and a ' shade ' species respectively, and are in accordance with field observations. The difference between the two species in their acclimatory response is discussed in terms of a species-specific alteration of the PSI : PSII stoichiometry. Besides the species-specific modulation of the accessory pigments, such an acclimation would provide a biochemical basis for the observed physiological differences. The monoculture results were used to differentiate the niches of the two species and suggested that Aphanizomenon would competitively displace Anabaena under N # -fixing, light-limited conditions. However, when both species were grown together, Anabaena became dominant and seemed to be the superior competitor for light. In order to explain this finding, the possible effects of release of allelopathic compounds, or dynamic aspects of light supply, are discussed.

show abstract

Measurement and Interpretation of Photosynthetic Light‐response Curves in Algae in the Context of Photoinhibition and Diel Changes

Cited by 567 publications

References 99 publications

Understanding the intertidal zonation of two estuarine red macroalgae fromex situphotoacclimative responses

Understanding the intertidal zonation of two estuarine red macroalgae fromex situphotoacclimative responses

The daily integral of growth by Planktothrix rubescens calculated from growth rate in culture and irradiance in Lake Zürich

Comparison of the light‐limited growth of the nitrogen‐fixing cyanobacteria Anabaena and Aphanizomenon

Contact Info

Product

Resources

About