Honors Marine Biology

Module 11

Coral Reefs

Class ChallengeThe Best Joke

Estuary Presentations

Coral Reefs are home to an amazing assortment of organisms and are truly the underwater equivalent of a diverse rain forest.

Coral reef communities are found in the tropical climates of the world because reef-building corals need warm temperature in order to survive.

They are found between the Tropic of Cancer and Tropic of Capricorn latitudes.

Upwelling along the Western Coastlines

Figure 10.1

Central America

South America

Africa

Coral Reefs

Examine Currents

This “band” around the earth receives a much larger portion of sunlight throughout the year than the rest of the world and has overall warmer climates.

The Coriolis Effect

Causes ocean currents to spiral clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

This effect results in the presence of cooler water off these western coasts, therefore it does not support the growth of corals.

Review: Module 4For corals to grow they need:

1. Hard surfaces, and

2. Shallow water in which light can penetrate.

Coral Reefs Grow on the Continental Shelf

Zooxanthellae

These types of corals cannot grow well without the presence of tiny algae called zooxanthellae.

When corals are stressed due to warm waters, toxins,or chemical imbalances in the water, they expel their symbiotic Zooxanthellae losing their color. If conditions don't improve enough for the Zooxanthellae to move back in, the

coral will die.

Corals need clear water to allow for superior light penetration.

Because of the presence of zooxanthellae, they need the light in order to photosynthesize the thrive in warmer water.

• Coral anatomy showing the photosynthetic symbiotic Zooxanthellae within.

Coral Reefs consist of two major components:

1. Reef Builders are organisms that actually produce the reef structure. These are the tiny animals called corals. They produce calcium Carbonate (limestone) which is their “armor” around their bodies.

2. Reef inhabitants

Taxonomy of Coral

Page 264 Figure 11.4

Phylum Cnidaria

Class Anthozoa

1. Subclass Alcyonaria (soft corals, sea fans and sea pens)

2. Subclass Zoantharia (sea anemones, corals)

Sea Pen

Soft Coral

Sea Fan

Sea Anemones

What kind of relationship do they have?

See Figure 11.6 (pg. 265) Diagram of

• Each corallite has a series of sharp edges radiating from the center of the corallite cup called Septa.

• Around its perimeter and pointed Columella extending upwards from the floor of a corallite cup.

Coral Growth FormationsFigure 11.7

• Corals have a large variety of growth forms based upon their budding patterns:

• Boulder Coral (Encrusting) : bud mostly sideways or uniformly upward, covering existing hard substrates.

• Branching coral: are mainly made up of vertically budded polyps.

• Foliacious Coral: use a combination of both horizontal and vertical directions.

The Coral Spawn

http://youtu.be/pnDJvhgPn8o

Blue Planet: Coral Sea: GBR - Coral Spawning

http://youtu.be/wsaZ8-I7akg

Types of Reefs

1. Fringing Reef: A type of coral reef that forms as a border along the coast.

Fringing Reef

Barrier Reef

2. Barrier Reef: A type of coral reef that occurs at a distance from the coast.

Barrier Reef

Atoll Reef

3. Atoll: A ring of coral reef with a steep outer slopes, enclosing a shallow lagoon.

Atoll Reef

formation

Lab: Diagram of Coral (Fig 11.6)

Homework

1. Module 11: Read pages 269 to 280.

2. OYO questions : 11. 7 – 11. 15

3. Study Guide: define: d-e; 14 – 26

4. Quiz on Coral polyp (Fig 11.6)

5. Class challenge: Share the most unique thing about yourself.