Artificial reefs

The popular conception of a “reef,” generally refers to a coral barrier found in a tropical marine environment. Here people imagine a wide variety of tropical species swimming within a labyrinth of hard corals, gorgonians, and sponges in search of shelter, prey or a place to graze.
Such a habitat is typical in tropical regions located near the equator, between the Tropic of Cancer and the Tropic of Capricorn. Here temperatures consistently range between 21° and 22° C and climatic conditions prove uniform throughout the year.
In contrast, areas with more temperate climates, such as the Mediterranean Sea, are unsuitable for most reef organisms. In such areas, “reefs” are replaced by “rocky bottom areas” characterized by a wide variety of benthic organisms, such as calcareous and encrusting algae, corals, vermetids, bryozoans, sponges, bivalves and polychaetes.
Both sets of conditions, tropical or temperate, produce fragile and complex ecosystems whose extent and distribution proves to be quite limited when compared to the total length of available coastline. This fact makes particularly disturbing the realization that, as attractive environments, they are subject to heavy, sometimes destructive, stress loads from the tourist and scuba diving industries. This results in the need for human intervention, in the need to find ways to protect these delicate ecosystems. One solution to this problem is to create new reef habitats, or “artificial reefs.”
However, sometimes (even often), these barriers are unplanned, the result of a vessel going down at sea. In such cases, the environmental damage caused by the sinking greatly outweighs any short-term benefit it offers.
In contrast, when an artificial reef is not accidental, but planned, materials suitable for extended submersion in a marine environment are normally used. Such materials are stable and environmentally sound, like, for example, cement or steel.
Once the material is introduced into the marine environment, it acts as a natural rocky bottom, providing potential living space for a new reef community. Furnishing this “suitable space” is the only human intervention needed, once in place, nature quickly takes over and, soon thereafter, the structure begins to lose its artificial character.
With each passing day, as numerous new living organisms begin to colonize the structure, what was once “artificial” now becomes a progressively intensifying reef ecosystem. In time, the steel and cement will disappear beneath a colorful blanket of undersea life.