Giant sea creatures, including sea spiders the size of dinner plates and jellyfish with six-metre long tentacles, have been found by Australian scientists in the deep waters around Antarctica.

Huge worms and giant crustaceans have been filmed during an expedition which trawled the floor of the Southern Ocean almost a mile below the surface. Many of the animals could not be identified and are to be sent to labs, possibly to be classed as newly discovered species.

Martin Riddle, leader on the research ship Aurora Australis, said: "Some of the video footage is really stunning. Gigantism is very common in Antarctic waters. Many (of the animals) live in the dark and have pretty large eyes. They are strange-looking fish. In some places every inch of the sea floor is covered in life. In others we can see deep scars and gouges where icebergs scour the sea floor as they pass by."

The voyage was part of an international effort to chronicle sea life in the icy ocean and monitor the impact of global warming and other environmental changes on Antarctic waters.

The expedition's three ships, the Aurora Australis, France's L'Astrolabe, and Japan's Umitaka Maru, returned to Australia last month with decks full of sea creatures taken from east Antarctic.

Experts believe the species will help them analyse how rising atmospheric carbon dioxide levels make the oceans more acidic, a factor scientists predict will make it harder for some marine organisms to grow and sustain their calcium carbonate skeletons.

Riddle said: "It is predicted that the first effects of this will be seen in the cold, deep, waters of Antarctica. What we saw down there were vast coralline gardens based on calcareous organisms and these are the ones that could really be lost in an increasingly acidic ocean."

This study, called the Collaborative East Antarctic Marine Census, is part of ongoing research under the International Polar Year initiative. Graham Hosie, leader of the census project on Umitaka Maru, said: "This research will help scientists understand how communities have adapted to the unique Antarctic environment. Specimens will be sent to universities and museums ... for identification, tissue sampling and barcoding of their DNA."

Some of the sea life was only filmed because it was too fragile to remove.