18 Jan 2019

'Fascinating' study probes climate change impact on Antarctic species

7:05 pm on 18 January 2019

A University of Otago computer model can now accurately predict how Antarctic shellfish grow and reproduce and how they will be affected by global warming.

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Associate Professor Miles Lamare says experiments will continue using the offspring of the original starfish used in the study. Photo: Supplied / University of Otago

A physical experiment, using 500 starfish collected from Antarctica's McMurdo Sound in 2016, showed the computer model's predictions were accurate.

Marine biologist and associate professor at the University of Otago, Miles Lamare, is leading the team of international researchers.

Prof Lamare said more shellfish species could now be tested with the technology, with the abundant Antarctic clam next on the list.

"It opens up a whole new set of tools and a whole new set of methods that we can start to apply to understanding how organisms in the Antarctic are going to respond to warming and other environmental changes down there," he said.

Using a specialised Dynamic Energy Budget Model, the team could establish "how the animal grows, how it reproduces and how it basically survives" under current Antarctic conditions.

They then tasked it with predicting how the organism would grow when subjected to temperatures that were four to five degrees warmer, to establish how the starfish might respond to the environmental effects of climate change.

Results from the physical experiment, which has just reached its two-year milestone, matched the predictions previously made by the computer model.

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Photo: Supplied / University of Otago

Acting scientific advisor for Antarctica New Zealand Fiona Shanhun said the model would be instrumental in future research endeavours.

"The Antarctic marine environment is very stable in terms of temperature and acidity, and it has been that way for a very long time," Dr Shanhun said.

"But we know that, with future environmental change, the oceans will become warmer and more acidic.

"For Miles to have this model up and running and potentially be able to apply it to other species is really fascinating," she said.

Prof Lamare said while the experiment with the original 500 starfish would continue with their offspring, the technology would now be used to predict the effects of climate change on other Antarctic shellfish species.

The sea stars, which have been growing in specialised tanks of varying temperatures and carbon dioxide levels in Dunedin, were able to reproduce but did not grow as big as they previously had.

In November, American divers collected a further 200 starfish from the Antarctic seas, which will allow scientists to look deeper into their physiological responses to changes in their surroundings.

The study was funded by the New Zealand Antarctic Research Institute with support from the Belgian Science Policy Office and the Scientific Committee on Antarctic Research.

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