Coral reefs constitute an essential and vitally important part of the nature of Earth. They are the second richest ecosystem on the planet and their role for the environment and normal life on the planet can hardly be underestimated. Coral reefs play a very important role not only for the environment, but they can be also very beneficial for humans contributing to the socioeconomic development of human societies. Nevertheless, in spite of numerous benefits of coral reefs, their survival is under a threat. Paradoxically, but it is human activities which represent the major threat to the survival of coral reefs, while it is humans who can benefit the most from the preservation of this unique ecosystem. In such a situation, it is extremely important to understand the significance of coral reefs, the existing threats to their survival and possible ways of the restoration and preservation of coral reefs for the well-being of the entire planet.
First of all, it should be said that coral reefs represent a unique ecosystem, which is quite different from any other ecosystem. Traditionally, scientists distinguish several categories of natural objects and living things, including animals, plants, fungi, bacteria, and protists. As for coral reefs they represent a combination of some of these categories. To put it more precisely, coral colonies are composed of many tiny cup-shaped animals called polyps.
Millions of polyps working together in a cooperative colony generation after generation create the limestone skeletons that form the framework of the beautiful reef. Remarkable coral reefs are formed in areas which are nutrient poor and basically coral reefs are located in tropical and partially temperate regions of the ocean. As a rule, coral reefs are formed in a zone extending at most from 30 degrees North to 30 degrees South of the equator. In fact, such a location of coral reef is not occasional since they cannot survive under the temperature below +18C and, what is more, they cannot grow at the depth of over 30 meters. In fact, it is not only low but excessively high temperature can prevent coral reefs from growing since the abnormally high temperature leads to the loss of zooxanthellae, which provides 95% of the energy to the coral host. The characteristic feature of coral reefs is the huge biodiversity, but all this biodiversity can exist only in the specific environment, with a defined range of temperature which allows coral reefs survive and develop.
At the same time, it is not only species living in the coral reefs’ ecosystem that vary, but there are also different types of coral reefs. In this respect, it should be said that types of coral reefs depend on the way of their formation. For instance, fringing reef is a reef that is directly attached to the shore or borders it with an intervening shallow channel or lagoon. Barrier reef is a reef separated from the mainland or an island shore by a deep lagoon. Also there may be patch reefs, which are isolated, often circular reefs, within a lagoon or embayment. Apron reefs are short and they resemble fringing reefs but more exploded. Bank reefs are linear or semi-circular in outline and larger than patch reefs. Ribbon reefs are long, narrow, somewhat winding reefs, which are often associated with atoll lagoons. Also there are atoll reefs, which are more or less circular barrier reefs extending all the way round the lagoon without a central island. Finally, table reefs are isolated reefs, approaching an atoll type but without a lagoon.
Coral reefs are characterized by huge biodiversity. For instance, over 4,000 species of fish can inhabit coral reefs, while along with fish, there are other species. It is possible to name various reef fish, such as parrotfish, angelfish, butterflyfish, grunts, snappers, and others. Along with fishes, coral reefs are homes for a variety of other organisms, such as sponges worms, mollusks, sea squirts, sea turtles and sea snakes.
It proves beyond a doubt that biodiversity is one of the major benefits coral reefs can bring to human since the preservation of biodiversity is vitally important for the survival of the entire planet. In addition, coral reefs provide people with food, since coral reef fisheries provide 10 to 25% of protein for people living along the coast. Moreover, coral reefs have a significant economic value. For instance, coral reefs with their biodiversity can be a great attraction for tourists, while the development of tourism can accelerate the development of local economy. Furthermore, many islands, in which people actually live, are built exclusively of reef material. What is more, coral reefs have a great resources for the pharmaceutical industry.
However, today, coral reefs face serious threats, mainly in the result of human activities. Among the most dangerous and destructive factors can be named the global warming and the pollution of the ocean which destructs coral reefs’ ecosystem. Uncontrollable fishing is another serious threat which undermines biodiversity of coral reefs.
In such a situation, it is important to preserve coral reefs from total extinction that may be done through the restriction of fishing. In addition, it is important to solve such global problems as pollution and global warming.
Recently, the coral reefs restoration technology has been introduced which is based on the use of low voltage electrical currents which are used to crystallize minerals dissolved in seawater onto steel structures on which coral reefs are naturally built.