Climate change: Marine life threatened as ocean oxygen levels drop

Oxygen levels in the world's oceans are decreasing due to warmer surface waters, which absorb less oxygen and are more buoyant, preventing oxygen from reaching deeper waters. This poses a threat to marine ecosystems reliant on oxygen. Changes will be felt in the southern Indian Ocean and parts of the Pacific and Atlantic by 2030, while Eastern Africa, Australia, and Southeast Asia will experience impacts in the next century. Additionally, increased carbon dioxide levels are making oceans more acidic, exacerbating the problem.

What is one reason why warmer surface water contributes to lower oxygen levels in the ocean?

• It becomes less buoyant.

• It absorbs more oxygen.

• It absorbs less oxygen.

• It becomes colder.

Why are marine ecosystems at risk due to declining oxygen levels?

• They depend on oxygen for survival.

• They rely on carbon dioxide for survival.

• They thrive in acidic conditions.

• They are unaffected by oxygen levels.

By what year will the southern Indian Ocean and parts of the Pacific and Atlantic start feeling the effects of deoxygenation?

• 2050

• 2030

• 2100

• 2025

Which regions are expected to experience the impact of deoxygenation in the next century?

• Northern Europe

• Pacific and Atlantic Oceans

• Eastern Africa, Australia, and Southeast Asia

• Southern Indian Ocean

How does an increase in carbon dioxide worsen the effects of deoxygenation?

• By increasing oxygen levels

• By cooling the ocean surface

• By reducing ocean salinity

• By making oceans more acidic and less habitable