Ecosystems around the world support a diverse array of plant and animal life. The biodiversity of these areas is dependent on the climate experienced within the regions which in-turn has a direct impact on the availability of food. The biodiversity found on land is substantially different than the biodiversity encountered within the world's marine ecosystems. In aquatic ecosystems, some sections of the world's oceans have more biodiversity than others. Areas where coral reefs are found support a wide variety of organisms. The location of a coral reef dramatically impacts its relationship with the surrounding plant and animal life. For example, due to their proximity to the shoreline, the fringing reefs have a significant association with both sea grass and mangrove depending on the position of the tide. The biodiversity around a coral reef also significantly relies on the time of day as some species rely on the reefs during the day while others rely on the reef at night.
The relationship between fish and coral reefs is a complex one. Coral reefs provide habitat to a vast number of fish species while several types of fish such as the parrotfish protect and clean the coral reefs. Research indicates that nearly a third of every single species of saltwater fish spends a portion of their lives within coral reefs. In their book "Coral Reed Fishes", Ewald Lieske and Robert Myers estimated that there were at least 6,000 species of fish within the world's coral reefs. Scientists are still perplexed over why so many types of fish live within coral reefs. Several theories such as the availability of food have been put forward to try and explain the phenomenon.
The species of fish found in coral reefs occupy various levels of the food chain with some such as sharks being predators while others such as parrotfish feed on algae. The fish species living in the coral reefs have developed a wide range of adaptations to ensure they thrive within their habitats. Unlike fish found within the open ocean that have evolved to prioritize speed, coral fish have adapted to dodge within the coral reefs. To optimize the movement of coral fish, their fins are developed differently from other fish. The coral fish have also established a wide range of colors and patterns primarily to provide camouflage. Coral fish differ from fish in the open sea in the way they feed. Due to the variation in food sources, some coral fish species change their food sources as they advance in age. Some of the most notable fish within the coral ecosystems include butterflyfish and goatfish.
Besides fish, several types of plants are found within coral reefs. Algae are one of the most important plant species found within coral reefs. They provide food for many organisms within the ecosystem. The type of algae within a coral reef varies with some being unicellular while others are more complex and multicellular. In some cases, algae may have a negative impact on the coral reefs. Pollution by farm chemicals may lead to the proliferation of algae which will reduce the oxygen available for the rest of the organisms within the ecosystem. Lower levels of oxygen inhibit the calcification of coral. To prevent the algae from overcoming the coral reef, several sea urchins feed on the algae.
Another plant species that significantly benefits from the coral reefs is the seagrass. Several types of seagrass inhabit the areas around and within the coral reefs. One of the most significant benefits of coral reefs to seagrass is that they shield them from waves which pose a significant risk as they could erode the sediment where the seagrass has taken root. The seagrass also benefits the coral reefs in a couple of ways primarily being as they shield the reefs from pollution and fresh water. In addition to this, the seagrass also provides shelter to organisms such as lobsters. Mangroves also have a significant role in the marine ecosystem. Mangroves are highly dependent on sediment for their nutrients, and coral reefs usually protect from strong currents which would reduce the amount of sediment available. The mangroves safeguard the reefs from the flood of silt.
Mammals within the coral reef ecosystem are rare sights. When mammals are spotted in coral reefs, they are usually visiting to feed. Some of the most common mammals in coral reefs include dolphins with species such as the spinner dolphin and bottlenose being common in the Great Barrier Reef. Within the Great Barrier Reef, a few species of whales are also found such as the humpback and Dwarf Minke whales.
Invertebrates are some of the organisms that make their habitat in the coral reefs. Invertebrates play a significant role in coral reef ecosystems with some such as sea urchins and sea slugs feeding on algae and seaweed preventing them from smothering the coral reefs. Some invertebrates such as bivalve live within the skeleton of the coral reef.
Some bird species are heavily dependent on the coral system. An atoll called the Midway Atoll which is located in Hawaii is home to nearly 3,000,000 birds. Among the birds that make their home on the atoll is the Laysan albatross, a species of albatross which is considered nearly threatened. The vulnerable short-tailed albatross also makes its home on the atoll.
Threats to Coral Ecosystems
The coral reefs found around the world face many threats such as mining and pollution. The risks significantly reduce the amount of coral available all over the world and thereby significantly affect the organisms that have adapted to rely on coral reefs. The threats are diverse and although some activities have an indirect impact they still affect the coral reefs. Coral mining is one of the most substantial challenges facing the reefs as massive amounts of coral are extracted to satisfy ever-growing demand. The extracted coral may be used in construction or the making of jewelry. Some fishing methods such as blast fishing also pose a high risk to the coral reefs. Pollution from farms raises the nutrient content of the sea which increases the number of algae in the sea reducing the oxygen available for the rest of the organisms.