Found mostly near the coastlines of islands and continents, fringing reefs are the most frequently spotted type of coral reef that we can study. Separated from the shoreline through shallow and narrow lagoons, they are also distinguished from atoll and barrier reef formations through their low slope reef flat and their slower growth, as well as their unique development which makes them use up a greater amount of the space between the reef slope and the surface.
What Are Fringing Reefs?
One of the interesting facts about fringing reef formations is that they can often stretch out for hundreds of yards from the shoreline, and the lagoons or backreef zones that they are associated with are extremely shallow and narrow. In fact, if a fringing reef grows very close to the shoreline, it may present no backreef zone whatsoever.
Although fringing and barrier reefs are quite similar, there are a few important differences one has to note, that always set them apart. Unlike barrier reefs, fringing formations are much closer to the shoreline – even the varieties that grow somewhat farther away. Also, they do not present any significantly deeper growth areas, while the development of barrier reef is less consistent, the reefs sometimes having small areas that are far deeper than the rest of the formations.
The Structure and Development of Fringing Reefs
Sea levels determined by plate tectonics or glaciation are among the main factors conducive to the growth and development of fringing coral reefs. These reefs will often grow either at the same rate as sea level growths (keep-up reefs) or slightly slower at the beginning (catch-up reefs). Catch-up fringing reef formations also accelerate their growth over time, however.
Fringing corals are formed from a reef flat that is relatively low sloped, and a portion found farther out at sea known as the reef slope. Fringing reef slopes are extremely steep, and often descend to the farthest depths that still allow for the growth of corals.
Most fringing reef formations are developed either vertically or expanding away from the shoreline. Some also develop sporadically, while others can be found alongside muddy sediments or at a greater distance from the sea shore, forming barriers that are fed by storms, and often end up forming larger lagoons.
Darwin believed that fringing reefs became the first types of reefs to develop around most landmasses, and they are also easily found near or farther off from the shorelines of many islands and continental regions today.
Some of the most well-known fringing reef formations are seen in the Bahamas or certain locations in the Caribbean. These reefs can, however, also be found in places like the Red Sea, and most can easily be spotted in the tropics, near the shoreline, where they are known as the most common varieties of coral reef formations to be found. In fact, many of the reefs found in the Great Barrier Reef (more than 700 of the 3400 reef formations) are actually fringing reef formations.
Fringing reefs are considered to be among the most fascinating types of coral reefs ever studied, and their widespread development places them among the most important coral reef formations in the world.