Mangroves are salt-tolerant trees, also called halophytes, and are adapted to life in harsh coastal conditions. They contain a complex salt filtration system and complex root system to cope with salt water immersion and wave action. They are adapted to the low oxygen conditions of waterlogged mud. Specialized root structures allow mangroves to live in oxygen-poor sediments. Mangrove trees are adapted for survival in oxygen-poor or anaerobic sediments through specialized root structures. Plants require oxygen for respiration in all living tissues including the underground roots.