A great variety of other organisms – including many types of invertebrate animals – assist the two primary types of reef builders (discussed above) in the reef-building process by depositing lesser amounts of carbonate particles.
These minor contributors include sponges, octocorals (“soft” corals), fire corals, and many other types of invertebrates. Individually, the contribution of each of these groups may be comparatively small, but collectively their contribution can sometimes be substantial.
At the broader spatial scale of the entire reef ecosystem, structure and formation is shaped not only by the dominant animals and plants. Rather, interactions among a host of other abiotic (“physical”) factors AND the underlying geology of the area also come into play. In fact, these physical factors usualy represent THE dominant influences on large-scale reef structure.
WHAT IS AN ECOSYSTEM? – Here, we define “coral reef ecosystems” as large, interactive areas of coral reef development containing many individual reefs and associated habitats (e.g., seagrass meadows). These ecosystem extends from the shorelines of tropical islands and coasts to the deep blue waters of the open sea, and includes all the marine life within the area as well as the non-living parts of their environment.
Most notably, such factors include sea floor depth profile, substrate composition, water movement, light penetration, and other variables that affect hard coral species distribution, growth forms, and abundance.
These varied and complex interactions typically impose a characteristic “zonation” pattern upon the overall reef ecosystem. This is true whether the reef is of the atoll, barrier, or fringing type.