Phytoplankton often feed on zooplankton.
Most corals are colonial organisms.
The carrying capacity of an environment for a species is determined by both number of predators and amount of food present. The euphotic zone in the ocean determines where calcareous corals can grow. Wetlands have both ecological and economic importance for humans. The largest number of coral species occur on the reef flat. The doubling time of a population is shortest during the exponential growth phase.