# Pearling more noticeable when co2 goes off?



## Soilwork (8 Feb 2017)

Is it just me or does pearling really start to become more pronounced after the co2 has switched off or is it just harder to notice the pearling amidst the tiny co2 bubbles and the pearling is just the same?

Much like when we do a water change and the plants pearl intensely.  Is it because there is more oxygen in the water after a water change or is it because there is less co2?

I'm wondering if my plants truly are pearling more after the co2 has gone off whether i need as much in the first place.


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## dw1305 (8 Feb 2017)

Hi all, 





Soilwork said:


> Is it just me or does pearling really start to become more pronounced after the co2 has switched off


I don't know the answer, but plants <"can store CO2 in their tissue"> to some degree, and at the end of the CO2 period the water will be fully saturated with oxygen. 

I think this means that there should be a period after the CO2 is turned off when pearling will occur at the same rate as when the CO2 was on, until the tissue held CO2 levels fall.





Soilwork said:


> or is it just harder to notice the pearling amidst the tiny co2 bubbles and the pearling is just the same?


Same would be my guess. 





Soilwork said:


> Much like when we do a water change and the plants pearl intensely. Is it because there is more oxygen in the water after a water change or is it because there is less co2?


I think it is a temperature and pressure effect, the tap water is cold and under pressure, meaning that it will hold more of all dissolved gases. When the water warms these gases come out of solution as bubbles. The bubble nuclei form on plants etc and you get pseudo-pearling. The bubbles won't be oxygen, but a mixture of nitrogen and oxygen (about 80:20 N2:O2).  

It is the same effect as when you throw a salted peanut into a pint of lager, the bubble nuclei form on the peanut, and you get the bubbles forming because the lager has added CO2 and is held under pressure. 

cheers Darrel


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## Soilwork (8 Feb 2017)

Thanks Darrel.  That makes sense.  However if the plants are storing the co2 in their tissue that will result in crossover rate of pearling, this must mean that the plant does not require as much co2 addition.


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## dw1305 (8 Feb 2017)

Hi all, 





Soilwork said:


> Thanks Darrel.  That makes sense.  However if the plants are storing the co2 in their tissue that will result in crossover rate of pearling, this must mean that the plant does not require as much co2 addition.


I'm not a CO2 user, but I assume that is why you turn the CO2 off before you turn the lights off. 

There is quite a lot of work on oxygen storage by aquatic plants, and emergent plants which grow rooted in anaerobic substrates can store and transport large volumes of oxygen in their aerenchyma.  

This is the oxygen generated during photosynthesis, I don't know whether they can store the CO2 generated by respiration  when they aren't photosynthesising, but my suspicion would be that they can.

cheers Darrel


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