Coral Reefs in Belize

What are coral reefs?

The mention of coral reefs generally brings to mind warm climates, colorful fish and clear waters. However, the reef itself is actually a component of a larger ecosystem. The coral community is really a system that includes a collection of biological communities, representing one of the most diverse ecosystems in the world. For this reason, coral reefs often are referred to as the "rainforests of the oceans." Corals themselves are tiny animals, which belong to the group cnidaria (the "c" is silent). Other cnidarians include hydras, jellyfish and sea anemones. Corals are sessile animals, meaning they are not mobile but stay fixed in one place. They feed by reaching out with tentacles to catch prey such as small fish and planktonic animals. Corals live in colonies consisting of many individuals, each of which is called a polyp. They secrete a hard calcium carbonate skeleton, which serves as a uniform base or substrate for the colony. The skeleton also provides protection, as the polyps can contract into the structure if predators approach. It is these hard skeletal structures that build up coral reefs over time. The calcium carbonate is secreted at the base of the polyps, so the living coral colony occurs at the surface of the skeletal structure, completely covering it. Calcium carbonate is continuously deposited by the living colony, adding to the size of the structure. Growth of these structures varies greatly, depending on the species of coral and environmental conditions-- ranging from 0.3 to 10 centimeters per year. Different species of coral build structures of various sizes and shapes ("brain corals," "fan corals," etc.), creating amazing diversity and complexity in the coral reef ecosystem. Various coral species tend to be segregated into characteristic zones on a reef, separated out by competition with other species and by environmental conditions.

Virtually all reef-dwelling corals have a symbiotic (mutually beneficial) relationship with algae called zooxanthellae. The plant-like algae live inside the coral polyps and perform photosynthesis, producing food, which is shared with the coral. In exchange the coral provides the algae with protection and access to light, which is necessary for photosynthesis. The zooxanthellae also lend their color to their coral symbionts. Coral bleaching occurs when corals lose their zooxanthellae, exposing the white calcium carbonate skeletons of the coral colony. There are a number of stresses or environmental changes that may cause bleaching including disease, excess shade, increased levels of ultraviolet radiation, sedimentation, pollution, salinity changes, and increased temperatures.

Because the zooxanthellae depend on light for photosynthesis, reef building corals are found in shallow, clear water where light can penetrate down to the coral polyps. Reef building coral communities also require tropical or sub-tropical temperatures, and exist globally in a band 30 degrees north to 30 degrees south of the equator. Reefs are generally classified in three types. Fringing reefs, the most common type, project seaward directly from the shores of islands or continents. Barrier reefs are platforms separated from the adjacent land by a bay or lagoon. The longest barrier reefs occur off the coasts of Belize and Australia. Atolls rest on the tops of submerged volcanoes. They are usually circular or oval with a central lagoon. Parts of the atoll may emerge as islands.

Coral reefs provide habitats for a large variety of organisms. These organisms rely on corals as a source of food and shelter. Besides the corals themselves and their symbiotic algae, other creatures that call coral reefs home include various sponges; molluscs such as sea slugs, nudibranchs, oysters, and clams; crustaceans like crabs and shrimp; many kinds of sea worms; echinoderms like star fish and sea urchins; other cnidarians such as jellyfish and sea anemones; various types of fungi; sea turtles; and many species of fish.

Why are coral communities important?
Coral reefs and their associated communities of seagrasses, mangroves and mudflats are sensitive indicators of water quality and the ecological integrity of the ecosystem. They tolerate relatively narrow ranges of temperature, salinity, water clarity, and other chemical and water quality characteristics. Reefs thus are excellent sentinels of the quality of their environment. Proper monitoring of reefs can identify changes in water quality or impacts from land-based activities.

Monitoring changes in water quality can help local resource managers understand the implications of actions occurring in watersheds that are associated with particular coral communities. These connections will help in development of sound management plans for coral reefs and other coastal and marine resources.

Man has had a long association with reefs. They are important fishery and nursery areas, and more recently have proved to be very important economically as tourist attractions. Reefs provide protection from erosion to coastlines and sand for beaches. However, reefs located near coastal populations are showing increasing signs of stress and are not faring as well as reefs, which are more distant from centers of human population.

What problems exist?
There are two types of stresses associated with reef systems: natural and human-induced. The effects of these stresses can range from negligible to catastrophic. Reefs display a surprising adaptation to short-term natural catastrophic events, such as hurricanes, and usually recover to normal community structure. These natural events can even be considered beneficial in regards to biological diversity. Severe storm events on land can topple large trees. This opens up the forest to re-colonization and results in a greater diversity of plants. This same process occurs with storm impacts to reefs. The damaged area of the reef is often re-colonized by a greater diversity of organisms than existed before the storm. In the long term this event benefits the ecological integrity of the reef.

However, reefs are not well adapted to survive exposure to long-term stress. Some examples include agricultural and industrial runoff, increased sedimentation from land clearing, human sewage and toxic discharges. Many land-based activities have important implications for reefs. Agricultural activities can introduce herbicides, pesticides, fertilizers and runoff from animal feed lots. Sewage discharges can introduce nitrogen and phosphate compounds along with pathogens and mixtures of toxins. Uncontrolled land clearing can result in erosion, with the resultant increase in sediment loads to surface waters. Roadways, parking lots and buildings consist of impervious surfaces.

These surfaces increase runoff rates and carry with those waters mixtures of dissolved substances to surface waters. The surface waters in any watershed eventually discharge into coastal or near-coastal waters. These waters can then impact coral communities associated with these discharge points. Thus, activities occurring in distant locations have impacts to reefs, which are far away from these activities.

Sea Environment
Effluent from shrimp farms pollutes and kills mangrove swamps which destroys necessary habitat for maritime shrimp and fish life cycles. Shrimp and fish spawn in the ocean but the shrimp larvas and some species of baby fish then migrate to the mangrove swamps to mature. They then venture out again into the ocean to spawn.

So the mangrove swamps are absolutely essential to the life cycle of shrimp and some fish species. What happens is this. The inland shrimp farms use antibiotics and specific germicides and fungicides in the tank water to keep the shrimp from getting diseases. The fecal waste from the shrimp animal itself is high in nitrogen as could be expected. The water in the shrimp tanks is changed often, allowing the waste water to run out over the land, killing the soil (with the salt water effluent) for any future agricultural use, and polluting the mangrove swamps. Thus, the nutrient and chemical rich effluent from the land based shrimp farms as well as fertilizers, herbicides and insecticides from agricultural run-off provides a more favorable environment in the mangroves for algae to grow, but it kills other flora and fauna and allows the algae to go unchecked, plugging the mangroves with thick pads of smothering algae. This profusion of fiberous algae and a greatly changed mangrove environment disrupts the ecosystem of the mangroves gravely and makes it impossible for young shrimp and fish to deveolp into mature breedable animals. It also kills the mangrove trees which form the mangrove swamps. Thusly, interruption of the lifecycles is caused by shrimp farm effluent and agricultural run-off. The land based shrimp farmers don't care because it puts their maritime competitors out of business, a typically selfish and uncaring , irresponsigle attitude.

Clams dug out of the mud in such localities often are heavily contaminated with agri-chemicals and heavy metals but there is no check of this, they go right to the soup pot or the restaurant table. Clams are called "concha" pronounced "kong'-cha ".

Consequently, less and less maritime shrimp and fish production occur do the interruption of life cycles by pollution and over harvesting or harvesting of undersized fish. This is common especially for sea bass ("corvina") and sword fish. If this keeps up unchecked, soon Eucador will not have mariculutre. If this happens, approximately 1 million Ecuadorians will be put out of work in fishing, cleaning, packing, freezing, metal can making and of course the shipping businesses. The ravenous "I, me, now, get-it-all" attitude prevalent in this "emerging" nation has to stop, they aren't future-oriented enough to see where they are hurting themselves. International boycot by developed countries seems to work but a lot of the products are sold in Ecuador or neighboring Latin American countries, so boycotting doesn't always work. What will work is that eventyally there will be no mariculture and mairproducts will have to be imported, doubling or trippling the prices.

Along the same line, reef destruction is caused by over harvesting of sellable black coral for jewelry and because of extensive effluent pollution in the form of raw sewage and heavy metals. Mercury pollution of streams from sloppy and irresponsible gold mining near Machala on the coastal areas and soil erosion from hundreds of small time open pit or hydrolicly exploited coastal gold mines and unkept areas around streams is common. Unpoliced chemical and expended petro product dumping, oiling of dirt roads, and errant use of agri chemicals contribute to a more contaminated Ecuador coast where contaminants both originate and of course concentrate from inland contamination and erosion.

Are there solutions?
There have been increasing efforts to establish better management and conservation measures to protect the diversity of these biologically rich areas. Management practices have historically focused on the coral reef proper and not considered associated communities, such as seagrasses, mangroves and mudflats or defined watersheds (which transport complex mixtures in their waters), in a meaningful manner. This attempted to manage the reef in isolation, like an island.

When reefs are considered as part of a larger watershed, the recognization of the complexity of environmental stressors can be understood. Management plans can be developed to lessen impacts to mangroves, seagrasses and the reef ecosystem, based upon scientific data and a better understanding of the system.

Ruppert, EE and Barnes, RD, 1994, Invertebrate Zoology, 6th Edition, Saunders College Publishing, Philadelphia
An Introduction to Coral Reefs, University of the Virgin Islands
Environmental Protection Agency's Office of Wetlands, Oceans, & Watersheds

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