Ocean plants have adapted to living in the marine environment and can vary from single cell organisms to thick forests of kelp. These plants are an important food source for invertebrates and fish, they provide oxygen to surrounding marine life, and they support many marine creatures by providing refuge and nursery grounds.
The term algae includes many different unicellular organisms capable of producing oxygen through photosynthesis, and are not necessarily closely related to each other.
Phytoplankton are primary producers of the ocean—the organisms that form the base of the food chain. WHOI explores the microscopic, single-celled organisms.