Antarctica’s fragile plankton ready for research 27 May 2024

Australian Antarctic Division

For the first time, a range of fragile and exotic marine creatures, captured in waters off Antarctica in perfect condition, are being housed in the Australian Antarctic Division’s research aquarium.

The gelatinous organisms include predatory ‘sea angels’ and ‘comb jellies’ that were captured in RSV Nuyina’s unique ‘wet well‘, during a recent voyage to Mawson research station.

Krill researcher Rob King said it was the first time such delicate animals had been brought back to Australia alive.

“It’s wonderful to see these animals alive and well, because for the last 30 years I’ve just seen them come in as pieces, or as dead organisms in trawl nets,” he said.

“These animals were all caught with Nuyina’s unique wet well system, so they were literally sucked through the side of the vessel in about five seconds, into a collection tank, and then transferred to an on-board aquarium that looked after all their needs on the way back to Tasmania.”

Despite appearances, some of the fragile invertebrates are formidable predators, feeding on other unfortunate zooplankton that was captured at the same time.

Sea angels, for example, are free-swimming sea slugs, a type of predatory ‘pteropod’ that feed on herbivorous pteropods, known as ‘sea butterflies’.

Then there are the comb jellies or ‘ctenophores’, which have retractable tentacles to capture prey, including larval and juvenile krill.

“It’s absolutely mesmerising to watch their tentacles appear, like spinning a web, to catch their prey,” Mr King said.

Other new zooplankton in the aquarium include salps, copepods (small crustaceans) and polychaetes (bristle worms).

Mr King said the zooplankton are an important part of the Southern Ocean ecosystem that have been poorly studied because of their fragility.

“We’ve done a lot of work on Antarctic krill, and we need to do a lot more. But we’ve neglected to study these other key organisms around krill, that could replace them if krill do poorly as the environment changes,” he said

“Now that we know we can catch them in perfect condition, we hope to provide a steady stream of specimens for the new Southern Ocean Research Aquarium that is being constructed in Hobart now.

“We hope to have experts from around the world conduct research on these organisms to better understand how the Southern Ocean ecosystem functions, and how it will cope with the incredible rate of environmental change that’s occurring there at the moment.”

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