Coral bleaching

Definition

Coral bleaching is a phenomenon that occurs when corals lose their symbiotic algae, called zooxanthellae, due to environmental stressors like increased water temperature or pollution. This loss leads to a pale or white appearance of the coral, which can result in decreased growth rates and increased susceptibility to disease. Coral bleaching is a significant concern as it highlights the fragility of coral reef ecosystems in the face of climate change and other global environmental issues.

5 Must Know Facts For Your Next Test

1. Coral bleaching can occur when water temperatures rise just 1-2 degrees Celsius above the normal range for an extended period.
2. If conditions improve, some corals can recover from bleaching by reabsorbing zooxanthellae; however, repeated bleaching events can lead to permanent damage.
3. Coral reefs support about 25% of marine life and are vital for coastal protection, fisheries, and tourism.
4. Pollution from land runoff, such as fertilizers and sewage, exacerbates stress on corals and increases the likelihood of bleaching.
5. The frequency and severity of coral bleaching events have increased dramatically over the past few decades due to climate change.

Review Questions

• How does coral bleaching relate to climate change and its impact on marine ecosystems?
  • Coral bleaching is directly linked to climate change as rising sea temperatures stress coral reefs, leading to the loss of their symbiotic algae, zooxanthellae. This not only affects the health and survival of corals but also disrupts the entire marine ecosystem that relies on coral reefs for habitat and food. As corals bleach and die off, the biodiversity supported by these ecosystems diminishes, showcasing the far-reaching effects of climate change on marine life.
• Discuss the potential consequences of coral bleaching on human activities such as fishing and tourism.
  • Coral bleaching can have severe implications for human activities like fishing and tourism. As coral reefs degrade, fish populations that rely on these habitats for breeding and shelter may decline, impacting local fisheries and livelihoods. Moreover, healthy coral reefs attract tourists for activities like snorkeling and diving; therefore, bleaching events can lead to reduced tourism revenue and negatively affect communities dependent on these economic benefits.
• Evaluate the effectiveness of current conservation strategies aimed at mitigating coral bleaching in the context of ongoing climate change.
  • Current conservation strategies aimed at mitigating coral bleaching include establishing marine protected areas, promoting sustainable fishing practices, and restoring damaged reefs through artificial structures or coral gardening. However, their effectiveness is challenged by ongoing climate change, which continues to raise ocean temperatures and acidify waters. While these strategies can help bolster resilience in local reef populations, they must be paired with global efforts to reduce greenhouse gas emissions and combat climate change at its source to ensure long-term survival of coral reefs.

Related terms

zooxanthellae: Photosynthetic algae that live in symbiosis with corals, providing them with energy through photosynthesis and contributing to the vibrant colors of coral reefs.

ocean acidification: The process by which oceans absorb excess carbon dioxide from the atmosphere, leading to a decrease in pH levels and impacting marine life, particularly organisms with calcium carbonate structures, like corals.

climate change: Long-term alterations in temperature and typical weather patterns in a place, which significantly impact ecosystems and biodiversity, including coral reefs.