The Stellwagen Bank National Marine Sanctuary is best described as a complex system of plants and animals whose lives are interdependent, delicately balanced, and sensitive to a myriad of constantly changing physical and chemical processes. As you look at the sea, this complexity will not be apparent, since the processes of wind and wave and the interaction of the plants and animals are largely hidden. The vitality and richness of the Stellwagen bank system can be known only if the connections and balances among its many components are understood.
The foundation for all marine and fresh water food webs consists of tiny organisms called plankton. Plankton is a general term describing the rich array of plants and animals that are usually too small to be seen with the naked eye that float or drift in great numbers near the surface. Plankton can be categorized into two basic types: phytoplankton and zooplankton. Phytoplankton refers to organism that can produce energy through the process of photosynthesis such as algae. Zooplankton refers to tiny animals which include fish and shellfish in the larval stage.
“Other invertebrates” is the term we use to distinguish a whole host of spineless animals that do not drift with the tides like plankton. Many of the species listed in the following sections are recognizable as attached creatures in their adult stages, yet most, marine invertebrates spend at least part of their life drifting on currents as zooplankton.