Ocean Warming and Acidification

Question 1

How does climate change affect coral reefs?

Answer 1

• coral bleaching, occurs when the loss of algae within corals causes the corals to bleach white
• some corals recover and some die
• occurs during higher ocean temperatures

Question 2

How does ocean warming affect marine species?

Answer 2

• metabolic and reproductive changes

- loss of habitat

Question 3

What is the main cause of ocean acidification?

Answer 3

• primarily due to increased CO2 concentrations in the atmosphere, & can be expressed as chemical equations.

Question 4

What is the chemical process by which carbon dioxide combines with water to create carbonic acid and then disassociates into hydrogen and bicarbonate ions?

Answer 4

• CO2 + H2O → H2CO3

- H2CO3 → H+ + HCO3-

Question 5

Which anthropogenic activities contribute most to higher volumes of CO2 in the atmosphere and thus ocean acidification?

Answer 5

• the burning of fossil fuels
• vehicle emissions
• deforestation

Question 6

How does ocean acidification damage coral formation?

Answer 6

• acidification makes it difficult for them to form shells, due to the loss of calcium carbonate (they cannot extract the carbonate they need from bicarbonate)

Question 7

How do marine organisms typically make calcium carbonate for their shells? Why does acidification prevent them from making shells?

Answer 7

• To make CaCO3 for their shells, marine organisms combine calcium ions, Ca+2 & carbonate ions, CO3-2
• With acidification, the increased concentration of hydrogen ions (H+) from the dissociation of carbonic acid bond with available carbonate ions (CO3-2) in seawater and form bicarbonate
• Hydrogen ions bond more readily with carbonate ions than calcium ions do
• Marine organisms can’t extract the carbonate they need from this bicarbonate ion, making it harder for them to build shells & exoskeletons
• If there are enough free H+ ions around, they can even break apart existing CaCO3 bonds, dissolving shells & skeletons that are already formed

Question 8

What is the impact of coral damage on the rest of the ocean ecosystem?

Answer 8

• Corals are the foundation of highly bio-diverse reef ecosystems, & provide food & habitat for a variety of marine life. When corals are damaged or die off, ocean biodiversity is severely impacted