Invertebrate Characteristics. Classification of the Phylum Porifera at a glance. I'm Cassandra Brooks. So, as we put more, uh, carbon dioxide into the atmosphere, the ocean is taking up more carbon dioxide, which reduces the pH or increases the acidity of the ocean. Donec aliquet. The segmented worms that live in the sea are referred to as polychaetes. // The Goldbergs Matt Bradley, Jeffrey Donaldson Mother, Articles H