Marine heatwaves are similar to heatwaves in the land. They warm up the waters in areas which they affect. Such localised patches of warm ocean forms and dissipates naturally when it cools off, in all oceanic systems.
In 2013 for the first time, a new patch of warm water appeared in the Pacific. This time the patch was massive and its effect was prolonging. Scientists called this anomaly of marine heatwave as “The Blob” and it lasted in the region until 2016.
A study released by the University of Washington yesterday tells us that “The Blob” might have triggered the death of around one million sea birds in a one year period between summer 2015 to spring 2016. Scientists describe the deaths as a devastating biological disorder.
In that time period, 62,000 common murres were found ashore in the coasts of Alaska, Washington, Oregon and California either dead or dying. Since most seabords that die never wash ashore, the researchers estimate the total number of deaths to be closer to 1 million.
The study found that most likely them murres must have died of starvation. In their review of studies of fish and plankton collected by fisheries during the time when the blob was at its peak, the team observed that warmer temperature increases metabolism among “cold-blooded” ocean dwellers.
The warm conditions also restrict the population of smaller fish – the prime choice of food for many seafaring creatures. The two instances create an ecological squeeze for food supply. The Murres, which have to consume about half their weight of food every day, must have suffered the consequences of this intense competition.
These scientists believe that similar mass die-offs seen in Cassin’s auklets and puffins can also be probably attributed to warming events. Localised warming of the ocean has been happening in more number since last century. The scale and rate of this warming have started increasing since 2013. The researchers see their findings as an early warning to things that are going to happen as climate change is intensifying globally.