| toxic alga | 1.32 | Nitrogen can also stimulate the growth of toxic algae that kill fish. | ||
| microscopic alga | 0.59 | The microscopic algae turns red in the sun, and where the algae form large colonies, the sea looks red. | ||
| symbiotic alga | 0.39 | Bleaching occurs when hot water prompts corals to expel their symbiotic algae. | ||
| harmful alga | 0.33 | The work was ordered because submerged, decaying trees could reduce oxygen levels in the reservoir and promote the growth of harmful algae. | ||
| harmless alga | 0.33 | Deadly parasite or harmless algae in Sydney water? | ||
| poisonous alga | 0.26 | The fish contained ciguatoxin from poisonous algae they had consumed. |