[gpodio]

Pearling occurs when the water is saturated with oxygen and additional oxygen produced by the plants simply forms a bubble and floats to the surface rather than being dissolved into the water. This occurs at different times depending on the rate of growth and oxygen levels during the night, but in general it occurs more towards the end of the light period or at least in the second half.

When you do a water change a similar thing occurs due to the pressure the tap water is held in the pipes. This saturates it with gasses and will therefore appear to make the tank pearl temporarily. If this continues longer than say half a day, I'd say that the plants are also contributing to the extra pearling and the tap water you added may be providing some trace elemenets that the plants were in short supply of prior to the change. This is evident when you do a water change and plants pearl like mad for a couple days then taper off until the next water change.

Hope that helps
Giancarlo Podio

 

[gpodio]

But the different species of plants have their own speed to make bubbles, do you think it depends of the thickness of the cuticle or epidermis cells walls or depends of the entire leaf thickness or depends of their particular use of the O2 produced by their photosynthesis?. Thanks. Maurici.

All plants release oxygen during photosynthesis, you just don't see the bubbles until the water is saturated. While I'm sure each plant has it's own rate and various properties of the plant may govern the rate of oxygen release, I think the growth rate is probably the biggest influence. Fast growing plants like many stems, riccia and glosso pearl a lot more than slow growing plants such as anubias and crypts for example. The more fast growing plants you have, the sooner your tank will reach oxygen saturation and begin to pearl.

Giancarlo Podio