scholarly journals A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated (WATER-PAM) Fluorometry

10.3791/52455 ◽  
2015 ◽  
Author(s):  
Anna R. Bramucci ◽  
Leen Labeeuw ◽  
Teaghan J. Mayers ◽  
Julie A. Saby ◽  
Rebecca J. Case
Keyword(s):  
Small Volume ◽  
Pulse Amplitude ◽  
Pam Fluorometry ◽  
Water Pulse

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
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