A recent study has found that a marine heat wave, known as “the Blob,” has killed approximately half of Alaska’s common murre population, marking the largest recorded die-off of a single species in modern history. The catastrophic loss points to broader changes in marine environments driven by warming ocean temperatures.
The Northeast Pacific heat wave spanned from California to the Gulf of Alaska in late 2014 to 2016 and raised temperatures by 2.5 to 3 degrees Celsius above normal levels. Common murres, known for their distinctive black-and-white feathers, play a critical role in regulating energy flow within the marine food web.
Researchers tracked extreme population declines at 13 colonies across the Gulf of Alaska and Bering Sea and counted over 62,000 common murre carcasses by the end of the heat wave. However, the colonies did not recover, with no signs of the populations returning to their previous size.
The study found that the collapse of a key food source, Pacific cod, contributed to the mass die-off. With temperatures rising in Alaska, the murres’ food supply dwindled, and about 4 million common murres died within the period from 2014 to 2016.
“The only reason we had this data and were able to detect this event was that we had these long-term data sets and long-term monitoring,” said Brie Drummond, coauthor of the study. Monitoring is essential for understanding future changes in marine ecosystems.
Other species, such as tufted puffins and king salmon, are also struggling to adapt to changing environments. While some animals may respond positively to warming water events, others will be unable to survive. Microplastics, ocean acidification, sea levels rising, and chronic oil spills are also contributing factors that scientists are still uncertain about.
The study highlights the need for further research on long-term effects of climate events on marine life and the importance of monitoring changes in marine ecosystems.
Source: https://edition.cnn.com/2024/12/26/science/alaska-heat-wave-murres-global-warming/index.html