In a study in which we want to study the rhodophyte Gracilaria vermiculophylla with PAM fluorometry (diving PAM) we are facing the problem that this small tubular algae doesn't cover the complete area of the dark leaf clip. How can we correct the measurements?
- Is it correct to add more algal biomass until the area that is measured is approximately covered up uniformly?
- Should we relativize the output to the area that was surveyed when we take measurements from a single thallus?
Pulse amplitude modulated (PAM) fluorometry is a commonly used method for measuring photosynthetic efficiency in algae. However, when the size of the algal tissue is smaller than the measurement area of the spectrometer, it can lead to inaccurate measurements. To correct for this issue, several methods can be used:
It is important to use the correct correction method to ensure that accurate measurements of photosynthetic efficiency are obtained. It is also important to consider the variability of the algae, as well as any environmental factors that may impact the measurements, such as temperature, light intensity, and nutrient availability.
Hi Hector,
In my understanding, the nature of the problem depends on what information you are trying to gain from the PAM. If you are just trying to measure relative parameters (i.e. rETR, NPQ and others) then assuming your background light is constant you should be able to get measurements. As Bjorn pointed out you may have to optimize the F0. The assumption that the background light is constant my be a poor assumption especially if your clip doesn't sit well on the macro algae. I would recommend doing a some tests to see how constant the red background light is. If the background light is not constant I would consider adding aluminium foil or something else around the clip to blockout background light.
If you are trying to measure absolute ETR, measuring of macroalgae absorption will be tricky. Here you may have to find a way of limiting the area of the clip to a know area that you are sure is completely covering the algae biomass.
Hope this helps and best of luck
-Boomie
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