Climate change is not just causing ocean warming; it’s also leading to sudden marine ‘coldwaves’, posing a severe threat to marine life. These coldwaves occur when winds and currents force cold water from the deep ocean to replace coastal waters, resulting in rapid surface temperature drops.
Recent research highlights a growing trend of such coldwave events, with intensified upwelling along coastlines observed over the past four decades. The consequences are dire, as demonstrated by mass deaths of marine species during extreme coldwaves.
In March 2021, a ‘killer coldwave’ along South Africa’s southeast coast claimed the lives of hundreds of animals across 81 species, including vulnerable manta rays and bull sharks. Despite their resilience, even though species like bull sharks are not immune to the sudden and severe temperature drops.
Tracking data reveals that bull sharks actively avoid areas of upwelling during their migrations, seeking warmer waters or shelter in shallow bays. However, the increasing severity of coldwaves raises concerns about their ability to evade these lethal conditions.
While global warming extends the ranges of tropical species towards the poles, sudden cold events pose a significant threat to their survival. As climate impacts unfold, it’s crucial to limit greenhouse gas emissions and conduct further research to understand and mitigate future risks to marine ecosystems.
The complexity of climate change underscores the urgency of action and the need for comprehensive scientific exploration to safeguard marine biodiversity and ecosystem health.
Source-The Hindu