雅思听力

🎧 Listening Transcript

Good morning, class. Today we're going to discuss the impact of climate change on marine ecosystems. One key point is ocean acidification, which occurs when the ocean absorbs excess carbon dioxide from the atmosphere. This process lowers the pH of seawater, making it more acidic. As a result, organisms like corals and shellfish struggle to build their calcium carbonate shells. Recent studies show that even a small decrease in pH can significantly reduce coral growth rates. Additionally, warmer water temperatures cause coral bleaching, where corals expel the algae living in their tissues. This not only weakens the corals but also disrupts the entire food chain that depends on reef habitats.