Recent research might finally identify the secret behind Greenland sharks, one of the most enduring species of all time, who sometimes live up to 500 years. That startling answer turns out to be a metabolism that doesn’t change. With this discovery, researchers overturned the conventional assumptions that had been developed based on understanding how these ancient creatures might adapt to climate change.
The Greenland shark belongs to Somniosus microcephalus and inhabits the deep Arctic and North Atlantic Oceans, as low as 8,684 feet deep. They become the vertebrates that live the longest, with a minimum average lifespan of 250 years and others over 500 years. What made them live that long had always remained elusive as scientists previously attributed it to cold environments coupled with minimal movement.
However, new research presented at the Society of Experimental Biology Conference in Prague from July 2 to July 5 suggests that the sharks’ longevity may be linked to their metabolic activity, which remains constant over time. “This is important for us as it shows the sharks don’t show traditional signs of aging,” explained Ewan Camplisson, a doctoral student at the University of Manchester.
The chemical process by which enzymes break down nutrients into energy to run life’s machinery and repair tissues normally decelerates with age in most animals. Such slowdown in this process results in reduced energy production, slower cell repair, and accumulation of cellular wastes. In the study on metabolism in Greenland sharks, samples of muscle tissue were obtained from 23 sharks caught off the south coast of Disko Island in central Greenland. They measured the activities of five different enzymes involved in metabolic processes in sharks and their responses to different temperatures.
The researchers demonstrated that the sharks’ activity of enzymes did not alter with age, proving there was no metabolic degradation in the Greenland sharks, as seen in other animals. This steady metabolism probably explains their high lifespan. Moreover, findings revealed that the activity of enzymes increased with the increase in temperatures, thus suggesting that global warming may significantly increase the temperature of the seas and dramatically alter the metabolism and hence the lifestyle of sharks.
Camplisson says he will keep studying the sharks’ metabolism and other hallmarks of aging to understand how best to protect them as global warming sends temperatures in their environment soaring. “Better understanding the anatomy and adaptations of a long-lived species such as the Greenland shark may allow us to improve human health,” he said.
While the impressive aging process has made it possible to sustain Greenland sharks for hundreds of years, this rapid change in the environment might be a challenge. Listed as “Near Threatened” by the World Conservation Union, this species may end up being another failure at adapting to climate change and other stressors caused by marine pollution.
What this discovery means, finding metabolism unchanged in Greenland sharks, is the penetration of major ideas into their longevity and some key questions as to what climate change may do to these ancient beings. The Greenland shark could be the key to unlocking new possibilities for human life and health as scientists further research the mysteries of aging.