Ecosystem

Ecosystem;

Introduction

Coral reef ecosystems are produced by coral animals that build cup-shaped external skeletons around themselves. Corals protrude from their skeletons to capture food and expose themselves to the sun. Exposure to sunlight is important because corals contain single-celled algae within their bodies. These algae carry on photosynthesis and provide both themselves and the coral animals with the nutrients necessary for growth. This mutuality relationship between algae and coral is the basis for a very productive community of organisms. The skeletons of the corals provide a surface upon which many other kinds of animals live. Some of these animals feed on corals directly, while others feed on small plankton and bits of algae that establish themselves among the coral organisms. Many kinds of fish, crustaceans, sponges, clams, and snails are members of coral reef ecosystems.

Because they require warm water, coral ecosystems are found only near the equator. Coral ecosystems also require shallow, clear water since the algae must have ample sunlight to carry on photosynthesis. Coral reefs are considered one of the most productive ecosystems on Earth.

Coral reefs, just like any other ecosystem on our planet, rely on a variety of biotic and abiotic factors to keep them healthy and functional. Without stable temperature, pH, light/dark cycles, water flow, salinity, and chemical composition of sea water, coral reefs could not exist, but without a stable trophic cascade, coral reefs could not survive. Trophic structure in any environment refers to the different levels of the food chain and illustrates the transfer of energy from one level to the next in the form of a pyramid; energy is always lost as it travels “up” the food chain.

Figure 1: Coral reef trophic pyramid, showing its trophic levels. On each level, several important groups of species are shown (Diagram by Alex Rose).

There are three categories of organisms in every ecosystem:...