A study has found that warmer ocean temperatures could threaten a unique species of shark.
Sharks are known as some of the most powerful – and most feared – creatures in our oceans. But now it turns out that a certain species could teach us how to improve heart health.
New experimental research presented at the ongoing conference of the Society for Experimental Biology in Prague shows that muscle metabolic activity may be an important factor in the incredible longevity of the oldest living vertebrate species in the world – the Greenland shark.
Scientists believe the findings could be good news for the conservation of this vulnerable species and for human health.
What sharks can teach us about living longer
Greenland sharks, also known as somniosus microcephalus, are the longest living vertebrates with a life expectancy of 270 to 500 years – and beyond.
“We want to understand what adaptations they have that allow them to live so long,” said Ewan Camplisson, a PhD student at the University of Manchester he is working on research, he says.
This longevity was previously thought to be due to the shark’s cool environment and minimal movement. It has now been discovered that the factors behind the species’ extreme longevity appear to be much more complex.
So Camplisson and his team decided to explore alternative theories.
“Most species show changes in their metabolism as they age,” explains Camplisson, “we want[ed] to see if Greenland sharks also show this traditional sign of aging or if their metabolism remains unchanged over time.
What tests did scientists perform on Greenland sharks?
To measure shark metabolism, Camplisson’s team of researchers performed enzyme tests on preserved muscle tissue samples from the creatures.
They measured the metabolic activity of the enzymes using a spectrophotometer – an instrument that measures the intensity of light absorbed after passing through a sample solution – in different age categories of sharks and ambient temperatures.
After these investigations, Camplisson and his team found no significant differences in muscle metabolic activity in different age categories sharks.
This suggests that their metabolism does not appear to decrease over time – and may even play a key role in their longevity.
“This is quite different from most animals, which tend to show some differences in their metabolic enzyme activity as they age,” says Camplisson, “the results support our hypothesis that the Greenland shark does not show the same traditional signs of aging as other animals.”
How do these findings increase our understanding of the Greenland shark’s health—and our own?
The results based on sharks the study also showed that the Greenland species’ metabolic enzymes were significantly more active at higher temperatures.
“This would suggest that shark red muscle metabolism is not specifically adapted to the polar environment, otherwise we would expect less of a temperature-related difference in activity,” says Camplisson.
But with climate change comes a particularly worrisome potential trend that may make long-lived species less able to adapt and therefore more at risk extinction.
“A female Greenland shark may not be sexually mature until she is 150 years old, and with such a long generation time, the species will have much less chance of adapting to anthropogenic changes in its environment,” explains Camplisson.
Camplisson does not stop researching Greenland sharks yet.
ADVERTISEMENTIn the future, he plans to test more enzymes and tissue types to gain an even deeper understanding of the shark’s metabolic activity in light of the effects of climate change.
“My ultimate goal is to protect species, and the best way to do that is to understand them better,” he says.
What do his findings mean for humans and heart disease in particular?
“These are problems that become more common and more serious as we age,” he says, “by studying the Greenland shark and its heart, we may be able to better understand our own cardiovascular health.”