Whakaari/White Island: Ash and gases from eruption could benefit nearby ecosystems

Tuesday, 10 December 2019

Whaakari/White Island's eruption as seen from the plane of tourism operator White Island Flights.

Despite ash, poisonous gases, steam and mud being thrown into the sky, scientists believe the eruption at Whakaari/White Island is unlikely to have a major environmental impact – and could actually benefit some ecosystems.

Recovery efforts are under way after Monday's volcanic eruption left six dead, eight missing and 30 being treated in hospitals across New Zealand, many with severe burns.

While the human toll of the disaster has been devastating, experts believe the effect on the natural environment from what is scientifically regarded as a relatively small eruption is likely to be minor.

The eruption at Whakaari/White Island could prove to be a boon for local wildlife, scientists believe.

The plume of ash and gas rose more than 3.5 kilometres into Earth's atmosphere, but with White Island 48km out in the Bay of Plenty ash fall is thought to have been largely localised and is unlikely to disperse over the mainland.

Despite the eruption sending a plume of ash and gas more than 3.5 kilometres into the air, the environmental impact of the eruption is likely to be minimal.

* White Island eruption live: 8 believed dead on island, 5 confirmed dead, many injured

* Whakaari/White Island eruption: Family of four among group of tourists still missing

Volcano expert Professor Tom Wilson says the nutrients released from the eruption could benefit the island's surrounding marine ecosystems.

* One dead as White Island volcano erupts in the Bay of Plenty

* A history of White Island eruptions: New Zealand's most active volcano

* White Island tourist captures dramatic footage of volcano eruption**

Residents near the coast of the North Island may experience some ash fall and could smell some of the volcanic gases, geophysicist Dr Jessica Johnson said, while a nearby marine reserve could also be affected.

White Island is an important breeding ground for Australasian gannets, but volcano expert Professor Tom Wilson at the University of Canterbury said ecosystems on the island – which was in a constant state of eruption from 1975 to 2000 – have probably adapted to its volcanic activity.

University of Canterbury atmospheric chemist Dr Laura Revell says the eruption is unlikely to have an environmental impact, but the matter thrown out would 'not be great for breathing in'.

'They will have had to develop in that environment with these frequent eruptions occurring for probably thousands of years,' he said.

'There is definitely a lot of material that will have gone up into the atmosphere, but White Island does release a lot of gas on a daily basis.'

Wilson said the regular release of nutrients in the chemicals from the island could help the marine ecosystem in its surrounding shallow waters thrive, and that the eruption may actually prove beneficial in the way that bushfires can aid forest regrowth.

'It could enrich marine life and help with plankton growth, which is what we have seen from other volcanic eruptions around the world.

'As long as it doesn't overwhelm it, an ecosystem can adapt and thrive after an eruption.'

Dr Laura Revell, an atmospheric chemist at the University of Canterbury, said volcanoes such as White Island generally produce sulphur dioxide that can form atmospheric aerosol – particles of fine dust or droplets of liquid suspended in the air.

'Aerosol has an important environmental impact. It can either absorb, scatter or reflect sunlight back to space, so after major volcanic eruptions we see a cooling at the surface.

'But this is unlikely in the case of this eruption, which was a fairly small one by global standards.'

Revell, who stressed that she had not seen the data from Monday's eruption, said the matter thrown into the atmosphere would likely be the same type of by-product of burning coal, and would 'not be great for breathing in'.

'But given it happened on an island and in a marine environment I would expect that the plume gets dispersed and mixed in with the atmosphere.

'I would doubt if there is much of an environmental impact in terms of air quality or climatic impact, as it was a fairly small eruption.'