Coral Reefs

Coral Reefs the “rainforest” of the sea

Home to the phylum cnidaria - radially symmetric (arrangement of body around a center point)

Polyp structure: attached to the floor of the ocean & surrounded by a circlet of tentacles .

three basic tissue layers

the gastrovascular cavity is lined with flagella, which filters out nutrients

contain organelles called cnidae (a type of stinging cell.)

Platform Reefs

Platform reefs usually lie far off of the shore. They are flat- topped reefs with shallow lagoons

http://oceanworld.tamu.edu/students/coral/coral2.htm

- Fringing Reefs form on the shores of most tropical islands.

-They are one of the few coral animals that can withstand the climate of the tropical waters.

-They can tolerate the warm, nutrient-poor surface.

Grow upwards and/or outwards

Fringing Reefs:

Fringing Reefs

http://www.biosbcc.net/ocean/marinesci/04benthon/crimg/fringingreef.jpg

-Most common type -This reef is attached, lying adjacent to the shore of a continent or island. -There is little to no lagoon (a body of water cut off from a larger body by a reef of sand or coral) between it and the shore

The Barrier Reef - serve as a barrier between the ocean and the land. They slow down the harsh waves, protecting the coast. -usually a wide, deep lagoon separating the reefs from the land mass. - only grows where there has been a change of sea level on the adjacent coast PICTURE: The Great Barrier Reef. It is located off the northeast coast of Australia . It measures up to 150 km long .

Atoll

a ring shaped coral reef

Created when an island,

which is encircled by barrier reefs, sinks. The sunken island leaves a reef that is circular.

Encloses a lagoon.

On top of under-water mountains formed by volcanoes

LOCATIONS & REQUIREMENTS FOR GOOD HEALTH

Coral Reef Locations

91.9% of the world’s coral reefs are located in the Indo-Pacific region.

Coral Reefs cover 284,300 square kilometers of Earth’s surface

There aren’t coral reefs on the west coasts of America and Africa because of upwelling and cold currents.

The Great Barrier Reef in Queensland, Australia is the largest coral reef in the world!

The Belize Barrier Reef is the second largest in the world!

The Red Sea coral reef is located off the coast of Saudi Arabia and Egypt!

wave action Coral Reefs need: warm, clear water sunlight calcium

Coral reefs have a symbiotic relationship with a type of microscopic algae, which require sunlight. Therefore, coral reefs must exist where sunlight penetrates so that they can thrive and grow. CORAL REEFS NEED: sunlight

Clear water allows for sunlight to reach the algae CORAL REEFS NEED: clear water

73-77°F (23-25°C) CORAL REEFS NEED: warm water

waves bring in food, nutrients and oxygen to the reef CORAL REEFS NEED: wave action

CORAL REEFS NEED: calcium used to build their limestone skeletons available in shallow waters

Importance of Coral Reefs and Symbiosis

Importance of Coral Reefs

Protect coasts from strong currents and waves by slowing down the water before it gets to the shore; hence the name “barrier reefs”

Homes for Sea Creatures

Coral reefs support about 4,000 species of fish, 800 species of coral and hundreds of other species, some of which are yet to be discovered.

Reefs help local economies through tourism, diving tours, fishing trips, hotels, and restaurants

Symbiosis

Coral Polyp

Algae in the coral polyp produces oxygen for the polyp

The coral polyp produces carbon dioxide for the algae (zooxanthellae)

Clown Fish and Anemones

Clown fish are protected by anemone’s stinging tentacles

Clown fish chases away anemone’s predators

Clown fish provide fertilizer for anemone

Crab and Coral

Crab eats coral tissue and mucous.

Coral provides protection for crab

Crab protects coral from fish and starfish.

Corals that have crabs living on them actually grow faster and live longer

“Cleaning Stations”

Tiny fish clean off fungal growths on bigger fish

The tiny fish get fed

Bigger fish avoid infections

“ Cleaning stations” are in found in reef environments

Animals on the Coral Reef Arthropods, mollusks, sponges, cnidarians and more..

Types of Animals

Coral reefs are home to many animals including sponges, fish, anemones, crustaceans, snails, and mollusks

These animals rely on corals for food and shelter

Sponges

Have a range of sizes. some varieties can grow to over 6 feet in diameter

No true tissues or organs. Their structure is composed of a simple collection of cells.

sponges are actually one of the most primitive animals in the sea

Live attached to surfaces in the ocean

More Sponges

Cnidarians

Some types of corals and jellyfish live on coral reefs

Large territories of hard corals form coral reefs

The sea anemone’s tentacles provide protection and safety for fish

The name Cnidaria comes from the Greek word "cnidos," which means stinging nettle

Mollusks

Many feed by filtering water from the coral reef

Octopi, clams, and more inhabit the reefs

There are about 112,000 species included in this phylum

One of the largest mollusks of the reef is the giant clam

Giant Clam

One of the largest mollusks on the reef

Can reach the length of 4 ft.

Largest bivalve mollusk

Lives in the shallow coral reefs of the South Pacific and the Indian Ocean

Arthropods

Find protection between coral branches

Shrimps, crabs, lobsters and more

Crustaceans are also predators in the coral reefs

Shrimp removes parasites and dead skin from reef fishes

They also come in various sizes ; The king Crab has an arm span of 12 feet.

Fish

They are the most colorful and diverse groups of animals on the reef

Their different colors allow them to camouflage themselves against the coral

The coral reefs provide different ways for the fishes to feed, live and reproduce.

Barracudas

Humuhumunukunukuapua’a ( humu-humu-nuku-nuku-a-pu-a-a )

The largest are 8 inches.

-They are very aggressive and make a whirring sound when scared.

-They are very Poor swimmers because they rarely use their tails.

-They Eat shell invertebrates

& sea urchins

-They also have the name

trigger fish because of a

dorsal fin which they can

erect to keep them in place.

Plankton Eaters There are many fish that feed on plankton. They include damselfish, wrasses, and groupers, just to name a few. Damselfish wrasses wrasses Groupers

There are also herbivore, invertebrate, omnivore, and piscivores fish. Herbivore fish Invertebrate fish Omnivore fish Piscivores fish

Echinoderms Are a group of animals that include starfish, urchins, feather stars, and sea cucumbers. Starfish Flaming sea urchin Feather stars Sea urchins Sea Cucumber

Echinoderms

CHARACTERISTICS:

spiny, rough skin

radial symmetry (based on a circle)

water vascular system (used for suction)

not segmented

Simple animals that lack a brain and complex sensing organs

Examples:

starfish

Sea urchins

Sand dollars

brittle sea stars

Sea cucumbers

Crown of Thorns Starfish Sea Urchin

Flatworms Flatworms are the simplest of worm groups. There are about 20,000 species in this group. They are bilateral, have an eyespot, have a simple nervous system, and have no internal body cavity. They can be free living or parasitic.

Christmas Tree Worm

They can grow up to 3 cm tall.

They grow in

large colonies on

Porites coral.

-They are very

sensitive to light and

pressure.

- They will retract into their tubes when bothered.

Background

Coral Reefs are extremely sensitive

They are affected by 2 main causes: Natural Disturbances (forces of nature) and Anthropogenic Disturbances (caused by humans)

Coral Reef Threats

Water Pollution-Petroleum products and chemicals are lethal to Coral Reefs. Raw sewage is dumped into the sea, bringing an overload of nutrients; algae take over the reefs, blotting out the sunlight corals need to live.

Fishing with explosives or cyanide-In depleted fisheries, people resort to desperate tactics to catch the fish that remain—one of those is dynamite. The explosions send dead fish to the surface and destroy living reefs.

Sedimentation, Construction along coasts, mining, farming, and logging of Rainforests cause soil run off which smothers coral reefs blocking sunlight that it needs to survive. Dangerous

Human-caused, or anthropogenic activities are major threats to coral reefs. Pollution, overfishing, destructive fishing practices using dynamite or cyanide, collecting live corals for the aquarium market and mining coral for building materials are some of the many ways that people damage reefs all around the world every day.

Anthropogenic Threats to Corals

27 % of world’s coral reefs lost in 2000 (1998 coral bleaching alone destroyed 16 % of reefs, half will never recover);

32 % in critical stage or threatened.

Reefs are disappearing fast

Or Acanthaster planci is a large star fish that eats coral.

Many other gastropods and fish have been known to destroy coral reefs, but not to the extent of the Crown of Thorns.

Crown of Thorns

One of the most significant threats to reefs is pollution. Land-based runoff and pollutant discharges can result from dredging, coastal development, agricultural and deforestation activities, and sewage treatment plant operations. This runoff may contain sediments, nutrients, chemicals, insecticides, oil, and debris.

Ways to Help?