Azolla which at one point maybe caused an iceage is freshwater only and a symbiotic organism with a cyanobacteria, and the bacteria can't tolerate salt, maybe t

Azolla which at one point maybe caused an iceage is freshwater only and a symbiotic organism with a cyanobacteria, and the bacteria can't tolerate salt, maybe there is something cool we could do with nitroplasts to improve sea vegetation to reduce CO2