Pearling Riccia in Non Co2 tank?

[Dominic]

As the title states- my riccia has been pearling in a non co2 tank, usually towards the evening, why is this?

It is a very basic tank, purely playsand as substrate, so co2 sources couldnt be coming from there, and there is hardly any water flow.

Am i missing something here? Why is it pearling?

 

[Andy D]

When the plants 'pearl' they are releasing oxygen.

 

[dw1305]

Hi all,

my riccia has been pearling. It is a very basic tank, purely playsand as substrate and there is hardly any water flow.

It is because you don't have much flow, and Riccia forms a mesh of interlocking thalluses. The water surrounding the Riccia becomes locally saturated with dissolved oxygen, meaning that any additional oxygen evolved from photosynthesis forms oxygen bubbles ("pearling"). These bubbles are retained in the Riccia mat, because of both the mesh morphology (traps them) and the low flow (doesn't replace the 100% saturated water with less fully saturated water).

Additionally you don't have any other plants (or much in the way of bacteria) to use either CO2 or oxygen.

This is actually an adaptation that a lot of algae make use of. It works because in the spring the pond water is relatively clear, meaning that enough PAR reaches the algal mass (that has overwintered on the pond bottom) to start photosynthesis. Oxygen bubbles are evolved, and trapped, in the algal mass, which eventually becomes buoyant and floats to the waters surface as "blanket weed". If it remained on the bottom, as warming occurred "green water" algae would proliferate in the water column and intercept all the available PAR.

cheers Darrel

 

[Dominic]

oh okay thanks, theres loads of other plants in there though, but with the likes of crypts dwarf sag, anubias moss etc.

 

[Henry]

This is actually an adaptation that a lot of algae make use of. It works because in the spring the pond water is relatively clear, meaning that enough PAR reaches the algal mass (that has overwintered on the pond bottom) to start photosynthesis. Oxygen bubbles are evolved, and trapped, in the algal mass, which eventually becomes buoyant and floats to the waters surface as "blanket weed". If it remained on the bottom, as warming occurred "green water" algae would proliferate in the water column and intercept all the available PAR.

cheers Darrel

Dammit plants are cool