<h4>Recent Bleaching Event in Great Barrier Reef</h4><p>Recent <strong>aerial surveys</strong> conducted by <strong>Australian authorities</strong> have confirmed widespread <strong>coral bleaching</strong> across <strong>two-thirds</strong> of the <strong>Great Barrier Reef (GBR)</strong>. This alarming discovery signals a dire threat, largely exacerbated by ongoing <strong>climate change</strong>.</p><p>The surveys highlight the urgent need for action to protect this iconic natural wonder. Such extensive bleaching events underscore the severe impact of rising global temperatures on marine ecosystems worldwide.</p><h4>Understanding Coral Bleaching</h4><p><strong>Coral bleaching</strong> is a process where corals expel the algae (<strong>zooxanthellae</strong>) living in their tissues, causing them to turn completely white. These algae provide corals with most of their food through photosynthesis and give them their vibrant colours.</p><div class='info-box'><p><strong>Key Fact:</strong> Corals are animals that form large underwater structures called <strong>reefs</strong>. They have a symbiotic relationship with <strong>zooxanthellae</strong>, which are single-celled algae.</p></div><h4>Causes of Coral Bleaching</h4><p>The primary cause of coral bleaching is <strong>increased ocean temperatures</strong>, often linked to <strong>global warming</strong>. When water temperatures rise above a certain threshold, corals become stressed.</p><p>Other stressors include <strong>ocean acidification</strong>, pollution, increased sedimentation, and extreme low tides. However, sustained high temperatures are the most significant driver of mass bleaching events.</p><h4>Impact on the Great Barrier Reef</h4><p>The <strong>Great Barrier Reef (GBR)</strong>, a <strong>UNESCO World Heritage site</strong>, is the world's largest coral reef system. It stretches over <strong>2,300 kilometres</strong> off the coast of <strong>Queensland, Australia</strong>.</p><div class='key-point-box'><p>The GBR is a critical habitat for thousands of marine species, supporting immense <strong>biodiversity</strong>. Repeated bleaching events severely compromise its ecological integrity and ability to recover.</p></div><h4>Consequences of Bleaching</h4><p>While bleached corals are not immediately dead, prolonged bleaching can lead to coral mortality. Dead corals disrupt the entire reef ecosystem, impacting fish populations and other marine life that rely on the reef for shelter and food.</p><div class='exam-tip-box'><p><strong>UPSC Insight:</strong> Understanding the causes, impacts, and solutions for <strong>coral bleaching</strong> is crucial for <strong>GS-III Environment and Ecology</strong>. Be prepared to discuss its link to <strong>climate change</strong> and its implications for <strong>biodiversity</strong> and <strong>coastal economies</strong>.</p></div>