About Marine Heatwaves

• A marine heatwave is a period of unusually high Sea Surface Temperatures (SST)  for an extended period of time (more than 5 days)  and is defined by its duration and intensity
  • Examples: Major marine heatwaves events are the Great Barrier Reef in 2002, the Mediterranean Sea in 2003, the Northwest Atlantic in 2012, the Northeast Pacific during 2013–2016.
• Factors causing Marine Heatwaves:
  • Climate Change: The heat from the rise in greenhouse gas emissions is mostly absorbed by the oceans which leads to its warming increasing the likelihood and severity of marine heatwaves. 
  • Ocean Currents: Changes in ocean currents can contribute to localized temperature increases and the formation of heatwaves. 
  • Atmospheric Influence: Atmospheric conditions like high-pressure ridges and strong winds can affect ocean temperatures by altering solar radiation and heat exchange between the atmosphere and the ocean. 
  • El Niño and La Niña Events: These climate phenomena can significantly influence ocean temperatures and alter the likelihood of marine heatwaves in certain regions.
• Impacts:
  • Migration: Shift and disruption in population of marine species as they migrate for more temperate waters raising fears of competition and invasive species.
  • Mass mortality events: It includes non-mobile species like coral, algae and sponges, that cannot escape the extreme environmental conditions.
  • Exacerbation of harmful algal blooms
  • Likelihood of more frequent and intensified extreme weather events