Mursaat towers are structures usually created by the mursaat along with the jade constructs and is always sealed by an Ether Seal. It causes the Mursaat Tower environment effect until the Ether Seal is destroyed. The towers sometimes emit a pillar of light from the top and levitate a collection of jade shards into the sky. According to the Ancient Seer in Ring of Fire, Eidolons feast on their energy.
|The Guild Wars 2 Wiki has an article on Ether Tower.