Presentation on theme: "Stop 1: Coral Reefs. How Do Coral Reefs Form? Coral reefs begin to form when free- swimming coral larvae attach to submerged rocks or other hard surfaces."— Presentation transcript:
How Do Coral Reefs Form? Coral reefs begin to form when free- swimming coral larvae attach to submerged rocks or other hard surfaces along the edges of islands or continents. http://www.amsl.or.jp/eng/image/b15_05.jpg
How Do Coral Reefs Form? As the corals grow and expand, reefs take on one of four major characteristic structures. 1. Fringing Reef 2. Barrier Reef 3. Patch 4. Atoll http://oceanservice.noaa.gov/education/kits/cor als/media/coral04a_240.jpg
3 Types of Reefs http://ecurrentaffairs.in/blog/gs-paper-i-geography- coral-reefs-rainforests-of-the-sea/2/
1. Fringing Reefs Most common Project seaward directly from the shore Forming borders along the shoreline and surrounding islands.
Most common in the Carribbean and Red Sea. It’s believed this is the first type of reef formed in the stages of coral reef formation.
2. Barrier Reefs Also border shorelines, but at a greater distance. They are separated from their adjacent land mass by a lagoon of open, often deep water. http://assets.inhabitat.com/wp- content/blogs.dir/1/files/2011/05/great-barrier-reef-
2. Barrier Reefs Barrier reefs form as the island around which a fringing reef forms sinks or subsides while coral keeps growing upwards. http://www.marin ebio.net/marinesc ience/04benthon/ crimg/barrierreef.j pg
But What is Coral? Corals are in fact animals Even though they may exhibit some of the characteristics of plants and are often mistaken for rocks.
But What is Coral? In scientific classification, corals fall under the phylum Cnidaria and the class Anthozoa. They are relatives of jellyfish and anemones. http://2.bp.blogspot.com/- Bd1AulpfbSk/TiRjJnqD- xI/AAAAAAAAAUU/cymAM6iYoYc/s1600/Jelly fish+beautiful.jpg http://ww2.valdosta.edu/~jlgoble/tclown1.jpg
But What is Coral? There are over 800 known species of reef- building coral worldwide, and hundreds of species of soft corals and deep-sea corals. http://gemmanews.files.wordpress.c om/2010/02/red-coral-1- 400x3001.jpg http://upload.wikimedia.org/ wikipedia/commons/5/51/Col pophyllia_natans_(Boulder_Bra in_Coral)_entire_colony.jpg http://daniellesdives.files.wordpress. com/2012/05/tree.jpg
The Variety of Coral Reefs Coral reefs can be found in both shallow and deep waters and are classified into 2 general categories: 1. Hard Coral 2. Soft Coral
Hard Corals Scleractinia, also called stony corals, are exclusively marine animals ; they are very similar to sea anemones but generate a hard skeleton. Much of the framework of coral reefs is formed by scleractinians.
Hard Corals There are two groups of Scleractinia : 1. Colonial corals - found in clear, shallow tropical waters - world's primary reef-builders. 2. Solitary corals - found in all regions of the oceans - do not build reefs. http://www.aquacon.com/images/CynarinaRed.jpg
Soft Corals The Alcyonacea, or the soft corals Do not produce calcium carbonate skeletons Neither reef-building corals nor do they lay new foundations for future corals.
Soft Corals Instead they contain minute, spiny skeletal elements called sclerites. Sclerites give these corals some degree of support and give their flesh a spiky, grainy texture that deters predators.
Soft Corals A gorgonian, also known as sea whips or sea fans (soft corals) Order of sessile colonial cnidarian found throughout the oceans of the world, especially in the tropics and subtropics. Individual tiny polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan. http://www.oceanservi ce.noaa.g ov/educati on/kits/cor als/media/ coral01a_4 62.jpg
Soft Corals A colony can be several feet high and across but only a few inches thick. They may be brightly colored, often purple, red, or yellow. http://www.triathlonshots.com/great%2 0barrier%20reef/gorgonian%20fan04200 018.JPG http://week.divebums.com/2006/ Sep05-2006/Cal-golden- gorgonian_barbara-lloyd.jpg http://non- photosyntheticcoralcare.groupsite.com/galleries/photo/47411/dl/ori ginal/gorgonian.jpg?1300772238
Deep Water Reefs In 1999, a deep coral reef 60 m below the surface was discovered by the United States Geological Survey (USGS) Center for Coastal and Wetland Studies near Pulley Ridge, an underwater barrier island west of the Dry Tortugas National Park off the southern coast of Florida. http://coastal.er.usgs.gov/flash/images/ pulleyridge.jpg
Deep Water Reefs The Pulley Ridge reef absorbs more light by increasing surface area and growing flat rather than the usual vertical growth seen in shallower coral reefs.
Deep Water Reefs August 2003, Emergency protection was introduced for the Darwin Mounds, a deep water cold water coral reef off the north west of Scotland. The mounds are situated in the top end of the Rockall Trough off north-west Scotland, in waters 1,000 meters deep.
Deep Water Reefs More is known about shallow water coral reefs in tropical zones than deep-water reefs discovered recently, however much research into these unique ecosystems is being conducted.
Coral Anatomy Almost all corals are colonial organisms. This means that they are composed of 100 to several 100,000 of individual animals, called polyps. Each polyp has a stomach that opens at only one end. This opening, called the mouth, is surrounded by a circle of tentacles. (Barnes, R.D., 1987; Levinton, 1995).
Coral Anatomy The polyp uses these tentacles for defense, to capture small animals for food, and to clear away debris. Food enters the stomach through the mouth. After the food is consumed, waste products are expelled through the same opening. (Barnes, R.D., 1987; Levinton, 1995).
Coral Physiology Most corals feed at night (Barnes, 1987). To capture their food, corals use stinging cells called nematocysts. These cells are located in the coral polyp’s tentacles and outer tissues. If you’ve ever been “stung” by a jellyfish, you’ve encountered nematocysts.
Coral Physiology Nematocysts are capable of delivering powerful, often lethal, toxins, and are essential in capturing prey (Barnes, R.D., 1987). A coral's prey ranges in size from nearly microscopic animals called zooplankton to small fish, depending on the size of the coral polyps.
Coral Physiology In addition to capturing zooplankton and larger animals with their tentacles, many corals also collect fine organic particles in mucous film and strands, which they then draw into their mouths (Barnes and Hughes, 1999). Corals Eating Corals Eating More Coral Eating More Coral Eating
Color Most reef-building coral gain their yellow to brown shades of color from the symbiotic algae that live within their tissue Other corals contain protective pigments that give them bright colors. Exposure to ultraviolet light (UVA and UVB) can destroy DNA
Color Some coral species dwelling in shallow waters have evolved protective pigments to reduce the negative effects of ultraviolet light. These pigments are often blue, purple, or pink and account for the bright colors found in some corals
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