Final answer:
Coral reefs are highly susceptible to temperature changes; even slight warming can provoke bleaching by causing corals to expel algae. Elevated CO₂ levels result in ocean acidification, further endangering these ecosystems and the marine life that relies on them. Human activities heighten these risks, making conservation efforts imperative.
Step-by-step explanation:
Coral reefs are extremely sensitive to changes in water temperature, and their health is directly affected by global climate change, ocean acidification, and water pollution. The phenomenon known as bleaching occurs when corals, stressed by higher temperatures, expel their symbiotic algae. This loss not only leads to a reduction in the vibrant colors for which these ecosystems are known but also has a detrimental impact on biodiversity and ecosystem services.
Furthermore, rising levels of atmospheric carbon dioxide (CO₂) exacerbate ocean acidification. This process decreases ocean pH and hampers the calcification necessary for corals to build their calcium carbonate structures. As a consequence, marine species diversity drops sharply, affecting food sources and shelter, while potentially harming local economies that depend on coral reefs for tourism.
Combined with human activity, such as agricultural runoff and overfishing, these changes threaten coral reefs worldwide. Without significant efforts to reduce carbon emissions and protect marine environments, the future of these vital ecosystems is uncertain.