The back reef is among the most important reef zones in any coral reef. Its role is often to provide shelter to a variety of sea creatures that form their habitats close to the protected areas of the lagoon and feed on the plant life growing on the areas of the reef crest that are not exposed to open sea currents and waves.
This side of the coral reef formation also plays an important role in containing lagoon reef zones, as well as maintaining their slow moving, warm currents to secure a safer environment for fragile coral reef marine species to thrive.
What Is a Back Reef?
Back reefs are the area behind the coral reef crest that features an upward slope as seen from the shoreline. They are essentially part of the reef formation – in fact, they are the area that is located closest to the lagoon and shore.
In reef formations that are closer to the shoreline – such as fringing coral reefs – these areas still exist, even though they are smaller, since the reef doesn’t always feature a lagoon.
The shallow water and even depth in this area allows for increased sunlight and gentler currents to facilitate the thriving of plant and animal life, although factors such as higher temperature, occasional exposure due to lower tides and increased sunlight, also inhibit coral growth, so you might not see too many actual corals on the back reef.
Back reefs can range between a few meters to many kilometers, depending on the size of the coral reef formation they are a part of. Stretching out and away from the shoreline, they are still very well-protected from wave stress by the reef crest, making it ripe for the presence of feeding and nursery areas.
Supporting Plant and Animal Life
Dugongs and manatees, as well as sea turtles and a wide variety of herbivore fish thrive in the back reef area, due to its remarkable propensity for growing seagrasses. In most cases, seagrass and other types of underwater plants can grow with ease here, due to the area’s natural ability to maintain a warm, well-lit and quite stable environment.
Moreover, plants are able to grow more easily, since back reefs are not as densely populated with coral colonies as other areas of the reef, such as the fore reef zone and reef crest.
The back reef’s ability to grow plants is especially beneficial for sea turtles. These species, now labeled as endangered by most experts, are often seen as resting on back reefs, especially in areas such as the Caribbean or on Indo-Pacific reefs. Hawskbill turtles and green turtles are most often seen behind the reef crest, spending a great deal of time between it and the shore, and feeding on seagrass while resting on back reefs and swimming through lagoons.
The back reef is one of the most essential areas of any coral reef, and plays an important role not only in the support of a few marine species, but in the continuity and integrity of the coral reef food chain, almost in its entirety.