Marine biologists say aquatic life is facing growing challenges as the ocean absorbs more carbon dioxide.
Victoria University marine biologist Dr Christopher Cornwall said carbon dioxide released by burning fossil fuels was absorbed by the ocean, changing the chemistry of seawater and making it more acidic.
The process, known as ocean acidification, affects organisms such as calcareous seaweeds and abalone, which rely on calcium carbonate to form and maintain their protective structures.
Increasing carbon dioxide levels could also fuel the growth of some opportunistic species, while marine heatwaves and coastal darkening were creating further pressures on ocean ecosystems, Dr Cornwall said.
“So what’s happening is our oceans are becoming warmer as the world is becoming warmer,” he said.
Coastal darkening occurs when sediment washed into the sea reduces the amount of light reaching underwater environments. It can affect photosynthesis in marine plants and algae.
Reducing greenhouse gas emissions was the solution, Dr Cornwall said.
“If we can do that, it’s going to be the biggest thing we can do to stop the effects of climate change manifesting even more intensely.”
Protecting and restoring marine ecosystems was another important measure, he said.
“So restoring these systems for the future with climate change resistant organisms, being able to more better manage these marine ecosystems and sustainably harvest from them.”
His comments come ahead of the 6th International Symposium on the Ocean in a High-CO2 World in Wellington this week from 13-16 October.
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