Estimation of Primary Productivity by Chlorophyll a in vivo Fluorescence in Freshwater Phytoplankton

Gilbert, Matthias; Domin, A.; Becker, Anette; Wilhelm, Christian

doi:10.1023/a:1026708327185

Cited by 80 publications

(56 citation statements)

References 43 publications

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“…To measure the exact amount of chlorophyll a per cell, the following uncertainties have to be considered. Because the absorption at the excitation wavelength (514nm) can vary relative to the chlorophyll a content due to differences in the excitation spectra, the 680‐nm fluorescence signal is quantitatively not simply correlated to the amount of chlorophyll a. Additionally, differences in the efficiency of energy transfer from carotenoids or PB to chlorophyll a, depending on the physiological state, lead to variation in the fluorescence intensity relative to the fluorescence content as well) 36–38). The overlap in the fluorescence emission spectra between APC (present in all Cyanobacteria) and chlorophyll a also influences the 680 nm signal.…”

Section: Discussionmentioning

confidence: 99%

“…Although the ratio of PC/chlorophyll concentration (judging by absorption spectra) must have been much lower in the senescent culture, the ratios of PC/680 nm fluorescence were quite similar when excited at 514 nm. Generally, different physiological states influence the ratio of chlorophyll fluorescence per chlorophyll content) 37, 38). However, in this particular case, the difference in chlorophyll content and 680 nm fluorescence could also be explained by a high contribution of APC to 680 nm fluorescence, assuming PC and APC concentrations are coupled.…”

Section: Discussionmentioning

confidence: 99%

“…We observed changes in phytoplankton mass and composition. Water mixing induced extreme temporal and spatial patchiness in phytoplankton distribution and led to intensive sampling in time and space (7–10). The partial destratification altered phytoplankton composition with an increase in small, flagellated eukaroytes (Chlorophyta, Bacillariophyceae, and Cryptophyta) at the expense of Cyanobacteria and large coccoid forms.…”

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Flow cytometric discrimination of various phycobilin‐containing phytoplankton groups in a hypertrophic reservoir

2002

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Background: Knowledge of phytoplankton structure is important information in water quality control. Lake restoration and sanitation measures in particular must be evaluated on the organismic level to valuate biological effects and assess the risk of potentially toxic Cyanobacteria blooms. We used and comparatively tested three independent methods for phytoplankton analysis in a hypertrophic reservoir under restoration. Methods: Nine unialgal cultures and outdoor samples were examined by high-performance liquid chromatography pigment analysis, microscopical cell counting, and flow cytometric (FCM) light scatter and fluorescence analysis to measure the percentage contribution of the major algal groups to chlorophyll a and biovolume. The FCM instrument settings and identification criteria were developed using a single excitation wavelength at 514 nm to

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Flow cytometric discrimination of various phycobilin‐containing phytoplankton groups in a hypertrophic reservoir

2002

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“…where E (µmol photons m -2 s -1 ) is the actinic irradiance, 0.5 is a multiplication factor because the transport of one electron requires two photons (one per photosystem) (Gilbert et al 2000;Kromkamp and Forster 2003), ā * phy (m² (mg chl a) -1 ) is the spectrally averaged (400-700 nm) chlorophyll a specific absorption coefficient (see below for its measurement). The measuring light peaking at 470 nm was chosen because it was the most appropriate to the English Channel's phytoplankton communities but also because almost all commercially available PAM and FRRF fluorometers are equipped with blue excitation lights.…”

Section: Photosynthetic Activitymentioning

confidence: 99%

Rapid light curves (RLC) or non-sequential steady-state light curves (N-SSLC): which fluorescence-based light response curve methodology robustly characterizes phytoplankton photosynthetic activity and acclimation status?

et al. 2017

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This study is the first in situ work comparing rapid light curves (RLC) and non-sequential steady-state light curves (N-SSLC) in their efficiency to characterize phytoplankton photosynthetic activity and acclimation status. Measurements were carried out at two time scales (daily and annual) using the Pulse Amplitude Modulated fluorometry on samples taken in the coastal waters of a macrotidal ecosystem (the Strait of Dover, eastern English Channel). RLC and N-SSLC were compared under a wide range of environmental conditions and phytoplankton composition in order to define the best methodology to accurately capture short and long-term adjustments in the functioning of the photosynthetic apparatus. The relationships between the photosynthetic parameters extracted from RLC and N-SSLC were also studied to evaluate the possibility to use RLC to predict N-SSLC photosynthetic parameters and thus obtaining the acclimation status at steady state. At daily scale, the maximum electron transport rate and light saturation coefficient resulting from RLC (respectively, ETRm_RLC and Ek_RLC) were found to follow more closely short-term environmental light variations than ETRm and Ek resulting from N-SSLC (ETRm_N-SSLC and Ek_N-SSLC) did. RLC were thus able to detect rapid changes in photosynthetic activity that would have been overlooked with N-SSLC measurements. At annual scale, few differences were found between RLC and N-SSLC. Variations of ETRm and α derived from RLC and N-SSLC were very similar but absolute values were lower for RLC measurements. Because, at daily scale, RLC better capture the short-term changes in photosynthetic activity than N-SSLC do, using RLC to predict N-SSLC photosynthetic parameters and getting information about steady-state acclimation status is not possible at this time scale. However, this can be done at seasonal scale.

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“…It is unknown whether light quality changes only modulate the amount of light being absorbed by diatoms or if there are other effect, possibly due to differential energy levels and other confounding factors. To differentiate between chromatic differential absorption and other effects we compared intensity with Qphar (Gilbert et al, 2000) which is the photosynthetically absorbed radiation weighing in specific absorption coefficients of the major pigments. Currently, no studies exist on the effect of light quality regarding the two main diatom photo-regulation mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Effect of Light Intensity and Light Quality on Diatom Behavioral and Physiological Photoprotection

et al. 2020

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In this study, we investigated the different photoregulation responses of diatom dominated natural biofilms to different light intensities and wavelengths, over a tidal cycle in the laboratory. We compared the overall effect of light spectral quality from its light absorption (Qphar) dependent effect. Two different conditions were compared to study photoprotective strategies: sediment (migrational) and without sediment (non-migrational). Three different colors (blue, green, and red) and two light intensities (low light, LL at 210 µmol.photons.m −2 .s −1 and high light, HL at 800 µmol.photons.m −2 .s −1) showed strong interactions in inducing behavioral and physiological photoprotection. Non-migrational biofilm non-photochemical quenching (NPQ) was much more reactive to blue HL than red HL while it did not differ in LL. We observed a biphasic NPQ response with a light threshold between 200 and 250 µmol.photons.m −2 .s −1 of Qphar that elicited the onset of physiological photoprotection. Similar HL differences were not observed in migrational biofilms due to active vertical migration movements that compensated light saturating effects. Our results showed that within migrational biofilms there was an interaction between light quality and light intensity on cell accumulation pattern at the sediment surface. This interaction led to inverse diatom accumulation patterns between blue and red light at the same intensity: LL (blue + 200.67%, red + 123.96%), HL (blue + 109.15%, red + 150.34%). These differences were largely related to the differential amount of light absorbed at different wavelengths and highlighted the importance of using wavelength standardized intensities. Different vertical migration patterns significantly affected the total pigment content measured at the surface, suggesting that cell could migrate downward more than 2 mm as a photoregulatory response. Colloidal carbohydrates patterns paralleled the vertical migration movements, highlighting their possible role in diatom motility. Our data strongly suggests a wavelength and Qphar dependent light stress threshold that triggers upward and downward movements to position microphytobenthic diatoms at their optimal depth.

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Estimation of Primary Productivity by Chlorophyll a in vivo Fluorescence in Freshwater Phytoplankton

Cited by 80 publications

References 43 publications

Flow cytometric discrimination of various phycobilin‐containing phytoplankton groups in a hypertrophic reservoir

Flow cytometric discrimination of various phycobilin‐containing phytoplankton groups in a hypertrophic reservoir

Rapid light curves (RLC) or non-sequential steady-state light curves (N-SSLC): which fluorescence-based light response curve methodology robustly characterizes phytoplankton photosynthetic activity and acclimation status?

Effect of Light Intensity and Light Quality on Diatom Behavioral and Physiological Photoprotection

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