scholarly journals Effect of light on photosynthetic efficiency of sequestered chloroplasts in intertidal benthic foraminifera (<i>Haynesina germanica</i> and <i>Ammonia tepida</i>)

2016 ◽  
Author(s):  
Thierry Jauffrais ◽  
Bruno Jesus ◽  
Edouard Metzger ◽  
Jean-Luc Mouget ◽  
Frans Jorissen ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Spectral Reflectance ◽  
Photosynthetic Efficiency ◽  
Pulse Amplitude ◽  
High Light ◽  
Feeding Strategies ◽  
Oxygen Production ◽  
Pam Fluorometry ◽  
Light History ◽  
Effect Of Light

Abstract. Some benthic foraminifera have the ability to incorporate functional chloroplasts from diatoms (kleptoplasty). Our objective was to investigate chloroplast functionality of two benthic foraminifera (Haynesina germanica and Ammonia tepida) exposed to different irradiance levels (0, 25, 70 μmol photon m-2 s-1) using spectral reflectance, epifluorescence observations, oxygen evolution and pulse amplitude modulated (PAM) fluorometry. Our results clearly showed that H. germanica was capable of using its kleptoplasts for more than one week while A. tepida showed very limited kleptoplastic ability with maximum photosystem II quantum efficiency (Fv/Fm = 0.4), much lower than H. germanica and decreasing to zero in only one day. Only H. germanica showed net oxygen production with a compensation point at 24 μmol photon m-2 s-1 and a production up to 1000 pmol O2 cell-1 day-1 at 300 μmol photon m-2 s-1. Haynesina germanica Fv/Fm slowly decreased from 0.65 to 0.55 in 7 days when kept in darkness; however, it quickly decreased to 0.2 under high light. Kleptoplast functional time was thus estimated between 11 and 21 days in darkness and between 7 and 8 days at high light. These results emphasize that studies about foraminifera kleptoplasty must take into account light history. Additionally, this study showed that the kleptoplasts are unlikely to be completely functional, thus requiring continuous chloroplast resupply from foraminifera food source. The advantages of keeping functional chloroplasts are discussed but more information is needed to better understand foraminifera feeding strategies.

scholarly journals Effect of light on photosynthetic efficiency of sequestered chloroplasts in intertidal benthic foraminifera (<i>Haynesina germanica</i> and <i>Ammonia tepida</i>)

2016 ◽  
Vol 13 (9) ◽  
pp. 2715-2726 ◽  
Author(s):  
Thierry Jauffrais ◽  
Bruno Jesus ◽  
Edouard Metzger ◽  
Jean-Luc Mouget ◽  
Frans Jorissen ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Quantum Efficiency ◽  
Benthic Foraminifera ◽  
Pulse Amplitude ◽  
High Light ◽  
Light Curves ◽  
Feeding Strategies ◽  
Pam Fluorometry ◽  
Light History ◽  
Effect Of Light

Abstract. Some benthic foraminifera have the ability to incorporate functional chloroplasts from diatoms (kleptoplasty). Our objective was to investigate chloroplast functionality of two benthic foraminifera (Haynesina germanica and Ammonia tepida) exposed to different irradiance levels (0, 25, 70 µmol photon m−2 s−1) using spectral reflectance, epifluorescence observations, oxygen evolution and pulse amplitude modulated (PAM) fluorometry (maximum photosystem II quantum efficiency (Fv/Fm) and rapid light curves (RLC)). Our results clearly showed that H. germanica was capable of using its kleptoplasts for more than 1 week while A. tepida showed very limited kleptoplastic ability with maximum photosystem II quantum efficiency (Fv/Fm  =  0.4), much lower than H. germanica and decreasing to zero in only 1 day. Only H. germanica showed net oxygen production with a compensation point at 24 µmol photon m−2 s−1 and a production up to 1000 pmol O2 cell−1 day−1 at 300 µmol photon m−2 s−1. Haynesina germanica Fv/Fm slowly decreased from 0.65 to 0.55 in 7 days when kept in darkness; however, it quickly decreased to 0.2 under high light. Kleptoplast functional time was thus estimated between 11 and 21 days in darkness and between 7 and 8 days at high light. These results emphasize that studies about foraminifera kleptoplasty must take into account light history. Additionally, this study showed that the kleptoplasts are unlikely to be completely functional, thus requiring continuous chloroplast resupply from foraminifera food source. The advantages of keeping functional chloroplasts are discussed but more information is needed to better understand foraminifera feeding strategies.

Monitoring of cold and light stress impact on photosynthesis by using the laser induced fluorescence transient (LIFT) approach

2010 ◽  
Vol 37 (5) ◽  
pp. 395 ◽  
Author(s):  
Roland Pieruschka ◽  
Denis Klimov ◽  
Zbigniew S. Kolber ◽  
Joseph A. Berry
Keyword(s):  
Photosynthetic Efficiency ◽  
Light Stress ◽  
Pulse Amplitude ◽  
Laser Induced Fluorescence ◽  
High Light Intensity ◽  
High Light ◽  
Persea Americana ◽  
Effective Quantum Yield ◽  
Fluorescence Transient ◽  
Fluorescence Measurements

Chlorophyll fluorescence measurements have been widely applied to quantify the photosynthetic efficiency of plants non-destructively. The most commonly used pulse amplitude modulated (PAM) technique provides a saturating light pulse, which is not practical at the canopy scale. We report here on a recently developed technique, laser induced fluorescence transient (LIFT), which is capable of remotely measuring the photosynthetic efficiency of selected leaves at a distance of up to 50 m. The LIFT approach correlated well with gas exchange measurements under laboratory conditions and was tested in a field experiment monitoring the combined effect of low temperatures and high light intensity on a variety of plants during the early winter in California. We observed a reduction in maximum and effective quantum yield in electron transport for Capsicum annuum L., Lycopersicon esculentum L. and Persea americana Mill. as the temperatures fell, while a grass community was not affected by combined low temperature and high light stress. The ability to make continuous, automatic and remote measurements of the photosynthetic efficiency of leaves with the LIFT system provides a new approach for studying and monitoring of stress effects on the canopy scale.

Endolithic algae photoacclimate to increased irradiance during coral bleaching

2004 ◽  
Vol 55 (1) ◽  
pp. 115 ◽  
Author(s):  
Maoz Fine ◽  
Laura Steindler ◽  
Yossi Loya
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Efficiency ◽  
Photosynthetic Electron Transport ◽  
Pulse Amplitude ◽  
Coral Tissue ◽  
Pam Fluorometry ◽  
Endolithic Algae ◽  
Symbiotic Dinoflagellates ◽  
Pam Chlorophyll Fluorescence

The photoacclimation of endolithic algae (of the genus Ostreobium) inhabiting the skeleton of the Mediterranean coral Oculina patagonica during a bleaching event was examined. Pulse amplitude modulated (PAM) chlorophyll fluorescence techniques in situ were used to assess the photosynthetic efficiency of endolithic algae in the coral skeleton and the symbiotic dinoflagellates (zooxanthellae) in the coral tissue. Relative photosynthetic electron transport rates (ETRs) of the endolithic algae under bleached areas of the colony were significantly higher than those of endolithic algae from a healthy section of the colony and those of zooxanthellae isolated from the same section. Endolithic algae under healthy parts of the colony demonstrated an ETRmax of 16.5% that of zooxanthellae from tissue in the same section whereas endolithic algae under bleached sections showed ETRmax values that were 39% of those found for healthy zooxanthellae. The study demonstrates that endolithic algae undergo photoacclimation with increased irradiance reaching the skeleton. As PAM fluorometry has become a major tool for assessing levels of stress and bleaching in corals, the importance of considering the contribution of the endolithic algae to the overall chlorophyll fluorescence measured is highlighted.

scholarly journals A Novel Thin-Film Technique to Improve Accuracy of Fluorescence-Based Estimates for Periphytic Biofilms

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1464
Author(s):  
Leon Katona ◽  
Yvonne Vadeboncoeur ◽  
Christopher T. Nietch ◽  
Katie Hossler
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Light Attenuation ◽  
Pulse Amplitude ◽  
Light Signal ◽  
Photosynthetic Parameters ◽  
Pam Fluorometry ◽  
Attenuation Coefficients ◽  
Thin Film Technique ◽  
Relative Errors

Recent studies suggest that photophysiological parameters for intact substrates with depth (e.g., periphytic biofilms, microphytobenthos) are overestimated by pulse-amplitude modulated (PAM) fluorometry. This overestimation results from depth-integration effects, following the activation of deeper photosynthesizing layers by an attenuated light signal. To mitigate this error, we propose a novel slide-based thin-film technique in which fluorescence is measured on a vertically representative subsample of the biofilm, spread evenly on a microscope slide. We compared bias and precision for photosynthetic parameters estimated through conventional PAM fluorometry on intact biofilms and through our novel slide-based technique, both theoretically and empirically. Numerical simulations confirmed the consistent overestimation of key parameters for intact biofilms, with relative errors up to 145%, compared to, at most, 52% on thin films. Paired empirical observations likewise demonstrated that estimates based on intact biofilms were consistently higher (up to 248%, p<0.001) than estimates from thin films. Numerical simulation suggested greater precision with the slide-based technique for homogeneous biofilms, but potentially less precision for heterogeneous biofilms with improper subsampling. Our empirical comparison, however, demonstrated some improvement in precision with the slide-based technique (e.g., the coefficient of variation for the maximum electron transport rate was reduced 30%, p=0.009). We recommend the use of the slide-based technique, particularly for biofilms that are thick or have small light attenuation coefficients. Care should be taken, however, to obtain vertically representative subsamples of the biofilm for measurement.

Use of pulse amplitude modulated (PAM) fluorometry for in situ measurements of photosynthesis in two Red Sea faviid corals

1998 ◽  
Vol 131 (4) ◽  
pp. 607-612 ◽  
Author(s):  
S. Beer ◽  
M. Ilan ◽  
A. Eshel ◽  
A. Weil ◽  
I. Brickner
Keyword(s):  
Red Sea ◽  
Pulse Amplitude ◽  
In Situ Measurements ◽  
Pam Fluorometry

Photosynthetic rates ofUlva(Chlorophyta) measured by pulse amplitude modulated (PAM) fluorometry

2000 ◽  
Vol 35 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Sven Beer ◽  
Christer Larsson ◽  
Orna Poryan ◽  
Lennart Axelsson
Keyword(s):  
Pulse Amplitude ◽  
Pam Fluorometry ◽  
Photosynthetic Rates

Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

scholarly journals Combined effects of inorganic carbon and light on <i>Phaeocystis globosa</i> Scherffel (Prymnesiophyceae)

2012 ◽  
Vol 9 (5) ◽  
pp. 1885-1896 ◽  
Author(s):  
A. Hoogstraten ◽  
M. Peters ◽  
K. R. Timmermans ◽  
H. J. W. de Baar
Keyword(s):  
Carbon Dioxide ◽  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
Harmful Algal Bloom ◽  
High Light ◽  
Combined Effects ◽  
Low Light ◽  
Phaeocystis Globosa ◽  
High Co2 ◽  
Dissolved Carbon

Abstract. Phaeocystis globosa (Prymnesiophyceae) is an ecologically dominating phytoplankton species in many areas around the world. It plays an important role in both the global sulfur and carbon cycles, by the production of dimethylsulfide (DMS) and the drawdown of inorganic carbon. Phaeocystis globosa has a polymorphic life cycle and is considered to be a harmful algal bloom (HAB) forming species. All these aspects make this an interesting species to study the effects of increasing carbon dioxide (CO2) concentrations, due to anthropogenic carbon emissions. Here, the combined effects of three different dissolved carbon dioxide concentrations (CO2(aq)) (low: 4 μmol kg−1, intermediate: 6–10 μmol kg−1 and high CO2(aq): 21–24 μmol kg−1) and two different light intensities (low light, suboptimal: 80 μmol photons m−2 s−1 and high light, light saturated: 240 μmol photons m−2 s−1) are reported. The experiments demonstrated that the specific growth rate of P. globosa in the high light cultures decreased with increasing CO2(aq) from 1.4 to 1.1 d−1 in the low and high CO2 cultures, respectively. Concurrently, the photosynthetic efficiency (FV/FM) increased with increasing CO2(aq) from 0.56 to 0.66. The different light conditions affected photosynthetic efficiency and cellular chlorophyll a concentrations, both of which were lower in the high light cultures as compared to the low light cultures. These results suggest that in future inorganic carbon enriched oceans, P. globosa will become less competitive and feedback mechanisms to global change may decrease in strength.

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