Kowbucha, seaweed, algae, vaccines, etc. could reduce cow methane emissions
Algae could become biofertilizer, bioplastic, pollution control (sewage and fertilizers), food / vitamins, fuel, fish and mushroom feed, and dyes/stabilizers
Bricks could be made from invasive algae
Solar panels could be on water
Algae could power buildings
Algae could be made into shoes
Water could be available in an edible blob
Electricity free algae street lamps could suck up CO2