Post #3144959

I don't supplement CO2 in my aquarium, so it is a limiting factor for the plants in there, as it is in many freshwater aquatic ecosystems. For a long time, the tapegrass Vallisneria spiralis dominated in the tank. Its cheat code is that it can use bicarbonate (HCO3-) as a carbon source for photosynthesis. It uses an enzyme, carbonic anhydrase, to transform the plentiful bicarbonate in my very hard tap water to CO2, which it then uses for photosynthesis. About half of aquatic plants have some ability to do this. This year I had a baby boom of mystery snails that have decided the Vallisneria is a snack, reducing its biomass. So this summer another plant, the dwarf aquarium lily Nymphaea stellata, has exploded. It can engage in a limited amount of bicarbonate use, but even more important are its floating leaves, which allow it to sidestep the aquatic carbon sources entirely and just use atmospheric CO2! I am considering setting up a CO2 bubbler system as I have in the past to give some of the other aquatic plants a leg up. I had taken it down when the snails were babies to help keep pH high to help their tiny shells grow.