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 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/corals/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.marinebio.net/marinescience/04benthon/crimg/barrierreef.jpg

Barrier Reef

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Barr

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Reef

3. Patch Reefs

Small, isolated reefs that grow up from the open bottom of the island platform or continental shelf.

They usually occur between fringing reefs and barrier reefs.

3. Patch Reefs

They vary greatly in size, and they rarely reach the surface of the water.

4. Atoll If the island keeps sinking and becomes

submerged, an atoll forms.

http://ambergriscaye.com/blueholetrip/art/bluehole.jpg

Blue Hole, Belize

Atoll Formation https://www.youtube.com/watch?v=btRCAQHqbdY

Click for Video

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/Jellyfish+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.com/2010/02/red-coral-1-400x3001.jpg

http://upload.wikimedia.org/wikipedia/commons/5/51/Colpophyllia_natans_(Boulder_Brain_Coral)_entire_colony.jpg

http://daniellesdives.files.wordpress.com/2012/05/tree.jpg

Coral Reef Classification

http://seaworld.org/en/animal-info/animal-infobooks/coral-and-coral-reefs/scientific-classification/

Common Ancestor

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.oceanservice.noaa.gov/education/kits/corals/media/coral01a_462.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%20barrier%20reef/gorgonian%20fan04200018.JPG

http://week.divebums.com/2006/Sep05-2006/Cal-golden-gorgonian_barbara-lloyd.jpg

http://non-photosyntheticcoralcare.groupsite.com/galleries/photo/47411/dl/original/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

More Coral Eating

Light Penetration

Article Read

http://www.whoi.edu/oceanus/feature/shedding-light-on-light-in-the-ocean

Interactive

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

References

http://coralreef.noaa.gov/aboutcorals/coral101/plantanimalmineral/

http://marinebio.org/oceans/coral-reefs.asp