Have you ever been to the ocean? Have you ever looked out over the vast and compelling ocean? Have you ever wondered what lies beneath the waves and ripples? Have you ever thought about the possibility of underwater, productive communities? Well, it may not be the community you were thinking of, but coral reefs are considered "the most diverse and productive communities on Earth". Coral reefs are very complex and are "ecologically important ecosystems" that provide food, medicine, and protection of the coast. Coral reefs have a specific anatomy and structure. There are many types of coral reefs and many things threaten coral reefs. Coral reefs also have specific animals that associate with them. There are many important pieces to the coral reef puzzle.
Coral reefs are comprised of "many diverse species of corals". Tiny organisms named polyps are responsible for creating these corals. Polyps are made of two separate cell layers with a non-tissue layer between them. The cell layers are known as the epidermis and the gastrodermis. The non-tissue layer is known as the mesoglea. Polyps also contain mesentery filaments. These filaments contain nematocysts, a pharynx, endothecal dissepiments, and the columella. Nematocysts are commonly used to capture food and endothecal dissepiments are horizontal layers of skeletal material. The columella is "the central axis of the corallites found below the mouth". A skeletal wall surrounds each polyp and is called the theca. Another feature of coral anatomy is the "calcareous plate-like structure known as septa". There are two types of septa, which are called insert septa and exsert septa. Besides septa having more than one type, there is more than one type of coral .
The coral that coral reefs are made of comes in more than one type. One type of coral is known as perforate coral. This type of coral is known to have "porous skeletons with connections between the polyps through the skeleton". Another type of coral is imperforate coral. Imperforate corals have completely solid skeletons. Corals not only have two different types, they also have different "growth forms". Some of the different forms are plocoid, meandroid, cocoid, spherical shaped, and phalecoid. Another important part of coral reefs are the categories and structures of them.
In the Caribbean, there are three basic types of coral reefs. These types are fringing reefs, barrier reefs, and atolls. Fringing reefs grow in shallow water and closely border the coast. Sometimes, fringing reefs are only separated from the coast by a narrow stretch of water. These reefs are characterized by depth, reef structure, and the plant and animal communities that inhabit them. The regions of a fringing reef entail a reef crest, the fore reef, and the "spur and groove" zone. The "spur and groove" zone is also called the buttress zone.
Barrier reefs exist when a lagoon separates a reef from land. Barrier reefs are parallel to the coast. These reefs include all the regions of a fringing reef and more. The extra elements in a barrier reef are patch reefs, back reefs, and bank reefs. Back reefs are the shoreward side of a reef. Bank reefs are reefs that "occur on deep bottom irregularities". Also, bank reefs are larger than patch reefs and either have a linear or semi-circular outline.
Atolls are the third important type of coral reefs. This type is an "annular reef that develops at or near the surface of the sea when islands are surrounded by reefs subside. Reefs of this type often separate a central lagoon. The most common shape for an atoll is circular or "sub-circular". There are two different kinds of atolls. One is known as the "deep sea atoll" and this kind rises from the deep sea. The other kind of atoll is found on the continental shelf.
There are many other types of coral reefs besides the three main ones. There are apron reefs, which resemble fringing reefs, but they have more of a slope to them. This type of reef extends from a "point" or the shore of a peninsula. Another type, as previously mentioned, is the patch reef. These are isolated and are usually circular reefs located within an "embayment". Patch reefs are also "dominated by large star and brain coral colonies". Ribbon reefs are long and narrow and are "usually associated with an atoll lagoon". Table reefs are another type of isolated reefs that do not have a lagoon. Another important aspect of coral reefs is there food source.
Coral reefs have to obtain food in order to provide food for other organisms. Zooxanthellae are responsible for providing coral reefs with food. These are often referred to as "unicellular yellow-brown algae". Their habitat is in the gastrodermis of "reef-building corals". This food source is responsible for allowing the growth and reproduction of corals in order for them to form a coral reef. The food source is provided in the form of "photosynthetic products". The zooxanthellae receive protection and access to light as a reward for providing the coral with food.
Like any other organism, coral reefs are prone to diseases. There are four main types of "coral diseases". The first main disease is known as white band disease. The second disease is black band disease which is commonly referred to as BBD. Both of the first two diseases "kill coral tissue while advancing in a band around the coral and leave the white coral skeleton behind". Coral reefs are also in danger of bacterial infections and shut down reaction.
Besides these four main diseases, there are other possible perils. Coral reefs are "susceptible" to tumors and parasitic worms. Most of these unfortunate infections or diseases are stress related. It is claimed that "anthropogenic stresses can increase a coral's susceptibility to these diseases". The temperature of the water a coral reef inhabits also affects the health of it. Warmer waters can raise the rate of infection.
Coral bleaching is another potential problem for coral reefs. This can occur when many “symbiotic” zooxanthellae are lost from the polyps’ tissue. This “loss exposes the white calcium carbonate skeletons of the coral colony”. Coral bleaching is known as the “whitening of coral colonies”. Coral bleaching can be caused by disease, excess shade, pollution, increased temperature, and many other things. Coral bleaching is mostly a result of “stresses or environmental changes”. However, coral reefs are threatened by more menacing things than just disease and coral bleaching.
Coral reefs are threatened by many natural and human-created problems. Sedimentation “smothers” coral reefs by blocking necessary sunlight from reaching the reef. Many people fish with explosives as a “desperate tactic” and they destroy the reefs. Another fishing method that is threatening to coral reefs is “cyanide fishing”. This is very destructive to fish and coral reefs. Water pollution causes chemicals to reach the reefs and these chemicals are very lethal to coral reefs. Even recreation can cause the destruction of these underwater communities because when people are careless they damage the coral. Other threats to coral reefs are over-fishing, coral mining, climate changes, and global warming.
These threats pose even more danger to the oceanic habitat because they harm the lives of animals associated with coral reefs. Many organisms rely on coral reefs. Coral reefs provide food and shelter for these needy organisms. Sponges are popular inhabitants of coral reefs. These sponges use “chips” of the calcium carbonate for food. Coral reefs are demonstrated as a habitat for many more organisms in the popular movie, Finding Nemo. Coral reefs are a very important part of the oceanic ecosystem and many people don’t even realize it.
Coral reefs are very complex and there is a vast amount of information about them. Without coral reefs, the underwater world would be a very different place. Many organisms would be homeless and starving if coral reefs didn’t exist. Coral reefs are susceptible to diseases and countless other threats. People need to be careful of their actions so that coral reefs continue to be part of our world. Everyone needs to realize that if they aren’t responsible for their actions then we might not have important parts of our ecosystem.
Subscribe to:
Post Comments (Atom)
3 comments:
Linds
Wow you were able to write a lot on this topic. It's such a vast but interesting topic to research. I've never thought of coral reefs as a community, but you really were right when you said they are as specialized and diverse as a community. I never knew there were so many different types of coral. I guess like everyone else I just assumed coral was mainly comprised of the same things. I had no idea that there are polyps, perforate coral, and different types of reefs even. I also had no idea that coral reefs obtained their food in such an intricate manner. These underwater communities and their importance and complexity is often overlooked by us land loving beings. Excellent post I learned a lot from it.
Linds,
I loved your introduction. Wow, who knew that polyps were so extensive in detail. You would think that the smaller, the simplier. But look at the human cell... But it's really interesting how coral can grow in different shapes and forms. It's really cool that they can have different "skin" as well. But it's really interesting about how they can grow in different locations and how they grow into reefs. But it's depressing how they can be killed and how they can be left. There's so many different things that can damage a coral reef, you think that people would have done more things for them. If they were to be completely destroyed, the ocean would be a horrible place. That's something that I would hope would never occur. Great work!!
Billy
Lindsey-
Excellent article! You really hit some of the very important topics on coral reefs. You can see bleaching if you ever visit Puerto Rico. It's reefs are barren of fish and any coral life. The chain-of-life is connected even under water. When the fishermen removed all the fish, the coral died. I was there only a year or two ago, and the underwater scene was not pretty. We can't afford to do that to our underwater life. It is so fragile. I enjoyed reading your article.
Post a Comment