Coral reefs are one of nature's most magnificent creations, filled with thousands of unique and valuable plants and animals. More than one quarter of all marine animals is dependent on coral reefs. Coral reefs are also a source of food and income for millions of people too. The coral reef ecosystems benefit humans commercially, recreation ally and environmentally.
Because of the complex interconnections between coral reefs, mangrove forests, sea grass beds, and many other different plants and animals, coral is very susceptible to destruction. One small change in any of these things can affect mass quantities of coral. That is why it is important to educate people about coral and how complex of a species they really are. That is the purpose of this report, to educate you and make you aware of that complexity. Coral is often mistakenly identified as a rock, but in all actuality, it is an animal. The actual coral is composed of small animals called coral polyps.
Most polyps are very small, although rare species can grow quite large. One coral branch or mound is composed of thousands of polyps. These thousands of polyps are called a coral colony. Polyps are nocturnal and stay inside their skeletons during the day. However, at night they can be seen when they stick their tentacles out to feed. Corals reproduce in many different ways.
Some species are hermaphrodites, and produce both sperm and eggs, and some are single sexed organisms. They can reproduce both sexually or asexually. In most species, the egg and sperm are released into the water and random fertilization occurs. This is called coral spawning. The larva is attracted to the light and swims to the surface of the water where it remains for weeks. If the larva can survive without being eaten by predators, it will sink back to the bottom of the ocean floor.
Hear it will attach itself to a hard substrate and will grow into a coral polyp. At this point, the coral polyp begins to reproduce asexually. As new polyps are built and added a colony develops. Eventually the coral colony matures and begins to reproduce sexually again, adding to the ever-continual cycle of life. One of the most amazing aspects of coral reproduction is that of mass coral spawning. In many parts of the world, on the same night of the year, every coral will spawn at the same time.
Millions of eggs and sperm are released into the water on the same evening in one of the most beautiful events that occurs in nature. Coral reefs are massive limestone structures that are home for more than a quarter of all marine life. As one of the most complex ecosystems on the planet, coral reefs are home to over four thousand different species of fish, more than seven hundred species of coral, and thousands of other plants and animals. The reef is actually built by the coral, but not all coral species build reefs. The most active builders on the coral reefs are hard corals.
As the polyps of stony corals grow, limestone for their skeletons is produced. When these polyps die, their skeletons are left and are used as a solid substrate for new polyps, which then build more skeletons over the old ones. The actual coral mound or coral tree is made up of thousands of layers of dead coral polyps covered by a very thin layer of living polyps. Coral reefs are divided into four different classes: fringing reefs, barrier reefs, atolls and patch reefs. Fringing reefs are the most common type of reef. They grow near the coastline around islands and continents.
They are separated from the shore by narrow, shallow lagoons. Barrier reefs grow parallel to the coastline. At their shallowest point they can reach the water's surface forming a barrier to ships trying to sail through them. The most famous example of a barrier reef is the Great Barrier Reef in Australia. It is the largest barrier reef in the world. Atolls are rings of coral that create a protective circle around a lagoon.
Atolls are formed around active volcanoes. Over time the volcano sinks into the sea leaving the coral reef. The reef continues to grow after the volcano is gone. This leaves a reef out in the middle of the ocean with a lagoon in the middle of it but no other land surrounding it. Patch reefs are small, reefs that grow up from the bottom of the ocean on an island or a continental shelf. They most commonly can be found between fringing reefs and barrier reefs.
They vary greatly in size, and will hardly ever reach the surface. Coral reefs have partnerships with other species that are often nearby reefs. Mangrove forests, sea grass beds, and nearby beaches all affect the growth of the reefs. Human interaction with any of these partners can have a drastic affect on the reefs. Mangrove forests can be found along muddy beaches and have several very important functions for coral reefs.
They act as nurseries for young fish and other coral animals. Leaves that have fallen from the trees provide food for fish and help enrich the water with needed nutrients. Lately there has been a problem with mankind cutting down many of the mangrove forests. This allows mud and silt to erode into the ocean covering the reef. Sea Grass Beds grow on shallow ocean floors and are also an integral part of the coral ecosystem. They act as nurseries for the young of many coral fish.
Sea Grass also acts as a filter, filtering out sand and silt from the water, preventing cloudy water from settling on nearby coral reefs. Sandy beaches also play an important part in the survival of the coral reefs. Like the mangroves and sea grass, the sand acts to filter sediment from the beach and land, keeping it from covering the reef. Human Interaction has a dramatic affect on the survival of the coral reefs. In the last half century, mankind has destroyed over 35 million acres of coral reefs. If this rate of destruction continues, 70% of the world's coral will be killed within our lifetimes.
Because so many people depend on the reefs for survival, trying to prevent the destruction of the reefs is a great priority. This is completed by the great number of elements that need to be in perfect harmony in order for the reef to thrive. There are many threats that humans pose to the coral, the increase of sedimentation, fishing, collection of coral, water pollution, and careless recreation all destroy coral reefs. Construction along the coasts, inshore construction, mining and farming upstream, and logging causes soil to erode and this soil flows downstream and eventually into the ocean, covering coral reefs. This eroded dirt can cloud the water, killing the coral by reducing the amount of oxygen produced by photosynthesis. Mangrove trees and sea grass beds act as filters for this dirt and sand, however, these trees and beds are also being destroyed removing the filtration.
This has led to an increase in the amount of sediment that reaches coral reefs. Fishing is also a major destroyer of the coral. Fishermen who are having trouble finding enough fish now use dynamite as a fishing tool. The fishermen bomb the area killing the fish, they then gather the fish and sell them. However, this dynamite also kills the coral in the area. Private divers trying to capture tropical fish for home fish tanks use cyanide and other chemical poisons.
This technique not only poisons the fish, but also the coral polyps in the area as well. The polyps will die and leave the coral a bleached white color. Water pollution is also been an increasing problem. Gas products and other chemicals spilled or dumped near the ocean will eventually find their way to the coral reefs.
Oil and gas leaked or spilled near a reef by recreational boaters or oil rigs also poison coral polyps and other marine life. Recently, trash has also become a big problem. Plastic bags can be swallowed by fish and turtles either suffocating them or causing them to starve. One of the biggest problems to the reefs is careless recreation. When people are uneducated about recreation near reefs can be careless and step on coral or run over it with boats. Careless divers who break off coral as souvenirs are steadily killing off much of the coral population.
The declining state of coral reef ecosystems has created concern by many scientists, managers, and government officials. There have been many government workshops and meetings since the problem has been recognized. There have been many organizations that have been created for the purpose of saving the coral reefs. But there are many things that need to be reconciled before the reefs can be saved. Hopefully, with instructions to businesses, and education of the people who are around the reefs, we can stop the destruction and start the rebuilding process..