Escalating Ocean Heat Might Affect Future Ecosystems


In a recent study published in Scientific Reports, it records that baby sharks will find it difficult to survive on the Great Barrier Reef, at least by the end of the century. This surfaced as climate change and warmer oceans led the creatures to be born smaller, exhausted and undernourished.

The latest study from James Cook University’s (JCU) ARC Centre of Excellence for Coral Reef Studies has put the focus on epaulette sharks, which is an egg-laying shark found only on the Great Barrier Reef.

According to the study co-author Jodie Rummer, the epaulette shark was a species that was “really tolerant” even to very challenging and changing conditions, including ocean acidification.

“We started investigating the effects of rising temperatures … and what’s particularly alarming is that temperatures seem to be its kryptonite. Warmer temperatures are really having a negative effect on at least the early development of this particular shark species.” Dr Rummer said.

Along with the JCU team, Dr Rummer, including lead author and PhD candidate Carolyn Wheeler, extensively studied the shark eggs and hatchlings in controlled environments, simulating current reef temperatures and predictions for the middle and the end of the century.

And as per the doctor, temperatures were expected to rise from 2 to 4.5 degrees Celsius by 2100.

Dr Rummer added, “We could control conditions tightly in the laboratory and isolate the effects we were seeing and associate them just with that elevated temperature effect.”

Meanwhile, Ms Wheeler said researchers found the warmer the conditions the faster the embryos developed. “The embryos grew faster and used their yolk sac quicker, which is their only source of food as they develop in the egg cast. This led to them hatching earlier than usual. This meant hatchlings were not only smaller, they needed to feed almost straight away — while lacking significant energy.”

This was a concern for the future of all species of sharks.

As what Dr Rummer asserted “If this shark is having trouble coping with ocean warming conditions, that’s going to be a really big problem for other shark species that are less tolerant and not as robust to changes in their environment.”

Thus, should one species in an ecosystem be impacted; it could cause effects for the flow-on to an entire ecosystem’s health. This emphasizes that our future ecosystems hugely rely on taking urgent actions to mitigate climate change.

Dr Rummer even cited that if ocean warming did not stop, sharks would have to find new cooler habitats to live in or adapt over generations.

“But sharks are at a particular disadvantage for adaption as they can’t change their DNA over generations fast enough to keep up with the changing planet.”

(Image source: ABC News)

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