Turtle-eating sharks help slow global warming, scientist says


Sharks help to reduce global warming by eating sea turtles and other creatures that consume carbon-rich sea grasses, an Australian scientist said Tuesday.

Marine ecologist Peter Macreadie of Deakin University in Melbourne examined the effect on sea grasses in Shark Bay, Western Australia, after an extensive local shark culling program.

Fewer sharks meant their normal prey such as sea turtles flourished, and sea turtles’ favourite food is sea grass.

“Sea grass store vast reserves of carbon within sediments and with more sea grass being consumed the carbon is unlocked and can be released into the earth’s atmosphere accelerating climate change,” Macreadie said in a university statement.

Macreadie said wetlands such as swamps, marsh and sea grass are able to store and bury carbon more than 40 times faster than trees and keep it buried for thousands of years if it is not disturbed, known as a blue carbon ecosystem.

“If we lost 1 per cent of the ocean’s blue carbon ecosystems it would be the equivalent of releasing 450 million tonnes of carbon annually – that is the emission of 97 million cars or the annual carbon emission of all of Australia,” Mcreadie told broadcaster ABC Tuesday.

His study was published Tuesday in the journal Nature Climate Change.

His finding came as 70 shark experts from around the world met in Sydney Tuesday to examine ways of preventing shark attacks along the 2,000-kilometre coastline of the state of New South Wales (NSW), including a dozen maulings and two fatalities in the past 12 months.

“There is never going to be a magic bullet,” Professor Daryl McPhee from Bond University told the meeting. He is looking at a non-lethal electric fence that deters sharks and stingrays that is being trailed in South Africa.

“We are not going to put devices into the water simply to placate people’s fears,” the government’s senior research scientist Dr Vic Peddemors told reporters. “We are only going to put technology in the water when we are convinced that they work and prevent potential shark attacks.”