ANCHORAGE, Alaska- A recent study has revealed that a marine heat wave, known as “the Blob,” led to the death of about half of Alaska’s common murre population, marking the most extensive die-off of a single species in modern history. Researchers found that the catastrophic loss of the common murres indicates broader changes in marine environments due to warming ocean temperatures, which are rapidly reshaping ecosystems and hindering the ability of these animals to thrive.
The Northeast Pacific heat wave, which occurred from late 2014 to 2016, significantly impacted the marine ecosystem from California to the Gulf of Alaska. The study, published on December 12 in the journal Science, highlighted that this was the largest and longest marine heat wave recorded in history, with temperatures rising well above normal levels.
Common murres, characterized by their distinctive black-and-white feathers resembling penguins, play a crucial role in maintaining energy flow within the marine food web in the Northern Hemisphere. While these birds have faced smaller die-offs in the past due to various environmental and human-induced factors, the unprecedented scale and speed of the die-off during the heat wave raised concerns among researchers.
According to Brie Drummond, a coauthor of the study and wildlife biologist at the Alaska Maritime National Wildlife Refuge, tracking extreme population declines at 13 colonies across the Gulf of Alaska and Bering Sea revealed a staggering number of common murre carcasses. Despite the significant loss, the researchers noticed no signs of the colonies returning to their previous size post-heat wave.
The decline in Alaska’s murre population was exacerbated by a dwindling food supply as Pacific cod, one of their primary prey, declined by approximately 80% between 2013 and 2017. An estimated 4 million common murres perished within the period from 2014 to 2016, illustrating the severe impact of the marine heat wave on these seabirds.
While further research is needed to understand why the murres are not recovering, experts believe that shifts in the marine ecosystem, particularly in food supply, are driving the changes. Dr. Falk Huettmann, an associate professor of wildlife ecology at the University of Alaska, Fairbanks, noted that reproductive challenges and relocation difficulties could also be contributing to the species’ struggle to rebound.
As temperatures continue to rise worldwide, leading to the reshuffling of ecosystems and the migration of various species, there is growing concern about the long-term impact of climate events on marine life. Huettmann highlighted other factors such as microplastics, ocean acidification, rising sea levels, and chronic oil spills as potentially exacerbating the challenges faced by marine animals.
In conclusion, the findings of the study shed light on the devastating consequences of marine heat waves on marine life, emphasizing the need for continued monitoring and research to understand and address the ongoing changes affecting ecosystems and species like the common murres in Alaska.