AT1 2025
Thursday, 13 March 2025 8:42 AM
- 25% of all marine life defend on healthy c
- Approximately 500 million people rely on
reefs as a source of food, medical resourc
Coral Reef Ecosystems
What is Coral?
A coral individual is made up of thousands of small structures called polyps. Each polyp is
a circular mouth surrounded by tentacles and they can combined to be one single animal.
Coral is an animal made up of thousands of tiny polyps that secrete calcium carbonate to
form a hard skeleton.
What is the role / importance of Zooxanthellae?
- Zooxanthellae are plants that photosynthesis.
- Providing food for coral polyps and giving polyps their colour - acting as the coral's
primary source of nutrition.
- Symbiotic relationship - algae that gets habitat to grow on (polyp tissues) whilst
polyp gets food source.
How does the calcium carbonate coral skeleton form?
Coral polyps draw in calcium and carbon particles inside the ocean.
Inside the polyps, these two minerals combine to create calcium carbonate (limestone).
Polyps excrete this material, which makes their skeleton grow.
How is the carbon in the atmosphere linked to this process?
Carbon dioxide in atmosphere --> absorbs into ocean --> carbon particles in ocean get
absorbed by coral --> turns into limestone skeleton
HARD CORALS - (hermatypic or reef building)
- Hard calcium carbonate skeleton
- Symbiotic relationship with zooxanthellae
- Each polyps has 6 tentacles or multiples of 6
- Rigid structure
SOFT CORALS - (ahermatypic or non-reef building)
- Most soft corals lack a hard external skeleton, instead soft corals contain small
calcareous sclerites in their body.
- Soft structure that can move
- Do not always have symbiotic zooxanthellae
- Each polyp has 8 tentacles or multiples of 8.
Thursday, 13 March 2025 8:42 AM
- 25% of all marine life defend on healthy c
- Approximately 500 million people rely on
reefs as a source of food, medical resourc
Coral Reef Ecosystems
What is Coral?
A coral individual is made up of thousands of small structures called polyps. Each polyp is
a circular mouth surrounded by tentacles and they can combined to be one single animal.
Coral is an animal made up of thousands of tiny polyps that secrete calcium carbonate to
form a hard skeleton.
What is the role / importance of Zooxanthellae?
- Zooxanthellae are plants that photosynthesis.
- Providing food for coral polyps and giving polyps their colour - acting as the coral's
primary source of nutrition.
- Symbiotic relationship - algae that gets habitat to grow on (polyp tissues) whilst
polyp gets food source.
How does the calcium carbonate coral skeleton form?
Coral polyps draw in calcium and carbon particles inside the ocean.
Inside the polyps, these two minerals combine to create calcium carbonate (limestone).
Polyps excrete this material, which makes their skeleton grow.
How is the carbon in the atmosphere linked to this process?
Carbon dioxide in atmosphere --> absorbs into ocean --> carbon particles in ocean get
absorbed by coral --> turns into limestone skeleton
HARD CORALS - (hermatypic or reef building)
- Hard calcium carbonate skeleton
- Symbiotic relationship with zooxanthellae
- Each polyps has 6 tentacles or multiples of 6
- Rigid structure
SOFT CORALS - (ahermatypic or non-reef building)
- Most soft corals lack a hard external skeleton, instead soft corals contain small
calcareous sclerites in their body.
- Soft structure that can move
- Do not always have symbiotic zooxanthellae
- Each polyp has 8 tentacles or multiples of 8.
