Final answer:
Coral reefs are threatened by elevated sea temperatures leading to bleaching, changes in water pH affecting calcification, and unsustainable harvesting for the pet trade. These factors contribute to species diversity loss and negatively impact coastal economies reliant on coral reef tourism.
Step-by-step explanation:
Reefs are in danger of becoming extinct due to a combination of environmental stresses. One major stressor is the elevation of sea temperature, as mentioned by Hoegh-Guldberg (1999). This temperature rise leads to coral bleaching, where corals lose their symbiotic algae and consequently their color and source of nutrition. Additionally, rising CO₂ levels are changing the pH of ocean waters, interfering with coral calcification, which is essential for coral growth and reef structure.
Moreover, the pet trade significantly impacts coral reefs as many marine species are harvested unsustainably to supply aquariums. This not only puts individual species at risk but also affects the overall ecosystem balance. The loss of species diversity due to dying coral reefs is detrimental to marine life since these ecosystems provide food and shelter to numerous animals. Such biodiversity loss also poses a risk to coastal economies that depend on coral reefs for tourism.
The cumulative effect of these stressors makes it hard to envision a sustainable future for coral reefs, emphasizing the urgent need for conservation efforts as outlined in sources like Pandolfi et al. (2003) and Roberts et al. (2002).