How does ocean acidification affect coral reefs?

Carbon Brief

19 Mar 201901:26

Summary

TLDRThe video discusses ocean acidification, a significant consequence of human carbon dioxide emissions. It explains that 30-40% of CO2 is absorbed by oceans, leading to a decrease in pH from 8.2 to 8.1 since the industrial era. This increased acidity raises hydrogen ion levels, which diminishes the availability of carbonate ions needed for coral growth. As these ions bond with hydrogen to form bicarbonate, corals struggle to rebuild their calcium carbonate skeletons, heightening their risk of mortality. The impact of ocean acidification poses a severe threat to coral ecosystems and marine biodiversity.

Takeaways

🌊 Around 30-40% of carbon dioxide released by humans is absorbed by the oceans.
📉 The pH of the world’s oceans has decreased from 8.2 to 8.1 since the start of the industrial era.
🔬 Increased ocean acidity leads to a higher concentration of hydrogen ions in seawater.
🦠 Coral has a hard outer skeleton made of calcium carbonate, essential for its structure.
⚖️ Ocean acidification reduces the availability of calcium carbonate in seawater.
❌ Carbonate ions that typically pair with calcium instead bond with hydrogen ions due to increased acidity.
🪸 With less calcium carbonate, corals face difficulties in rebuilding and growing their skeletons.
⚠️ The challenges in growth increase the risk of coral death.
🌍 Ocean health is crucial as it directly impacts marine ecosystems and biodiversity.
🔄 Human activities significantly influence ocean chemistry, leading to long-term environmental consequences.

Q & A

What percentage of carbon dioxide released by humans is absorbed by the oceans?
-Approximately 30-40% of carbon dioxide released by humans is taken up by the oceans.
What has happened to the pH of the world's oceans since the industrial era?
-The overall pH of the world's oceans has fallen from 8.2 to 8.1 since the start of the industrial era.
How does ocean acidification affect the concentration of hydrogen ions in seawater?
-As oceans become more acidic, the number of hydrogen ions in seawater increases.
What compound forms the hard outer skeleton of coral?
-The hard outer skeleton of coral is made of a compound called calcium carbonate.
What are the components that make up calcium carbonate?
-Calcium carbonate is made of calcium ions and carbonate ions.
How does ocean acidification affect the availability of carbonate ions?
-Ocean acidification causes the amount of carbonate ions to fall, as some pair with hydrogen ions to form bicarbonate instead of pairing with calcium.
Why do corals struggle to rebuild and grow their skeletons in acidic oceans?
-With less calcium carbonate available due to ocean acidification, corals find it more difficult to rebuild and grow their skeletons.
What is the consequence of reduced calcium carbonate availability for corals?
-Reduced availability of calcium carbonate increases the chances of coral death.
What role do hydrogen ions play in the process of ocean acidification?
-Hydrogen ions pair with carbonate ions to form bicarbonate, decreasing the concentration of carbonate ions needed for calcium carbonate formation.
Why is calcium carbonate important for marine ecosystems?
-Calcium carbonate is essential for the formation of coral reefs, which provide habitat and shelter for numerous marine species.