First, as they grow, they produce much of the oxygen that other marine organisms need to breathe.
(they; grow; ) (they; produce; much of the oxygen; T:First; T:as they grow) (other marine organisms; need; to breathe) Context(other marine organisms need,List([58, 85))):(the oxygen; to breathe; other marine organisms)
other marine organisms need,List([58, 85))
they they other marine organisms the oxygen
grow produce need to breathe
much of the oxygen T:First T:as they grow
to breathe
other marine organisms