London: A team of scientists has claimed that geoengineering our climate with the help of volcanoes may result in a decrease in the level of oxygen in lakes, threatening marine life.
According to a report in New Scientist, the claim has been made by Matthew Hurtgen at Northwestern University in Chicago and his colleagues.
Volcanoes spewed so much sulphate into the atmosphere 94 million years ago that the oceans were starved of oxygen and 27 per cent of marine genera went extinct.
The scientists at Northwestern University say that geoengineering our climate could inflict a similar fate on some lakes.
They measured sulphur isotopes in sediments on the floor of the Western Interior Seaway.
The WIS was a vast body of water that divided the continent of North America down the middle at the time.
The team also developed a model to simulate the impact of volcanoes on ocean chemistry.
Before oceanic oxygen levels tumbled, something caused a big change in atmospheric sulphate levels.
“That something was probably volcanoes,” said Hurtgen.
He said that their sulphate emissions triggered vast phytoplankton blooms and much of the ocean’s oxygen was gobbled up as these died and decomposed.
According to the team’s model, oceanic sulphate was extremely low prior to the eruptions.
"This has implications for geoengineering,” said Hurtgen.
"Like the mid-Cretaceous ocean, most modern lakes are poor in sulphate, so it’s possible that geoengineering the climate, using sulphate aerosols to reflect sunlight, could trigger blooms and ultimately anoxia in some lakes,” he said.