Airweed was a kelp-like plant that grew in the undersea Fields of Air near Mahri Nui. Airweed produced bubbles of breathable air which could by harvested by Hydruka. The Matoran living in Mahri Nui depended on air harvested from airweed for survival.
Notes
The Fields of Air teemed with these plants, which the Matoran called "airweed." Each plant produced bubbles of air which could be merged together to form larger bubbles. The Matoran used hydruka to harvest the air. The Matoran used this air to create large bubbles around the buildings of Mahri Nui as well as smaller, personal air bubbles for Matoran who ventured outside of the city.1
Airweed was a plant that grew in the undersea Fields of Air near Mahri Nui. These plants produced pure air, which could be harvested from inside them by Hydruka or released due to significant impact tremors. The air produced by these plants made it possible for the Matoran to survive underwater.2
Airweed plants were precious to Mahri Nui. They produced air bubbles naturally, which could be harvested using creatures called hydruka. The air bubbles allowed the Matoran of Mahri Nui to survive in the Pit and protected them from being mutated by the waters. Airweed grew in the Fields of Air adjacent to Mahri Nui.3
The Matoran of Mahri Nui used air bubbles harvested from airweed to breathe.4