Coral Reefs

What are reef-building corals largely composed of?

Calcium carbonate.

How do marine organisms form their carbonate shells?

They take dissolved carbon as CO2 or bicarbonate from the water.

What are the organisms that build coral reefs called?

Coral polyps.

How do coral polyps build reefs?

They combine calcium from the sea with carbon to form calcium carbonate.

What is the chemical equation for forming calcium carbonate in reefs?

Ca2+ + 2HCO3– → CaCO3 + CO2 + H2O.

What is coral bleaching?

The whitening of corals when they are stressed by pollution or warmer oceans.

What causes coral bleaching?

Loss of symbiotic algae (zooxanthellae) from coral tissue due to pollution or increased water temperatures.

What has the increased oceanic CO2 concentration caused?

Ocean acidification.

How does ocean acidification affect coral calcification?

It slows coral calcification by reducing available carbonate ions.

What happens when atmospheric CO2 is absorbed by the ocean?

Carbonate ion concentration decreases, making them unavailable to corals and other marine calcifiers.

What are some consequences of ocean acidification?

Dying of coral reefs, molluscs, crustaceans, and plankton like foraminifers and coccolithophores.

What are other impacts of ocean acidification on organisms?

It decreases immunity, increases water noise, and increases cloud formation.