In a world-first, Kiwi scientists are conducting climate change experiments on black corals to see whether they can survive marine heatwaves.
The unique organism is an important part of the ocean's ecosystem as it forms giant structures for fish to shelter in and other creatures to cling to.
Fiordland has recently suffered consecutive marine heatwaves, with sea temperatures rising by up to 4.5C, killing millions of sea sponges.
It's estimated about 8 million black coral live in the area, and Victoria University marine biologist Professor James Bell told Newshub he's worried about how they'll fare in future.
"What we're really concerned about is whether these organisms will be able to cope with marine heatwaves, but we're also interested in understanding if they have mechanisms to adapt to these marine heatwaves," he said.
Black coral is usually found thousands of metres deep, but in Fiordland the trees can be found in about five metres of water because the unique tannin layer on the water's surface creates a darker marine environment, so the corals grow in a much shallower habitat. This makes it much easier for scientists to research the coral, some of which are hundreds of years old and metres wide.
With a permit from the Department of Conservation, a group of scientists are removing small black corals off the sea floor for experiments. Something that's never been done before.
"It's pretty unique, nobody else has looked at marine heatwave impacts on temperate black corals. Our study will provide insights that will be useful to people who are interested in black corals globally because the results will tell us something about how black corals respond to those climate impacts," Prof Bell said.
The work is funded by the George Mason Charitable Trust and supported by the Southern Fiordland Initiative, whose boat the researchers stay on during their voyage.
Fifteen samples have been taken back to the lab in Wellington, where PhD student Amber Kirk will carry out the experiments.
"It's really exciting. I love problem-solving and kinda figuring out new things - but it's also quite daunting. They are protected species and so long-lived," she said.
The corals will be put through a simulated marine heatwave in the lab - and a range of changes will be monitored, such as microbes, tissue necrosis, growth rates, death and oxygen consumption.
"I'll be heating them up and seeing how their respiration changes over time, seeing if that increases which would indicate stress, or whether it stays stable", said Kirk.
Once the preliminary experiments are carried out this year, then another 115 black coral samples will be collected in January for further marine heatwave research.
