Australasian Science: Australia's authority on science since 1938

Surviving Extinction in the Abyss

Isopods

One group of isopods has been in the deep sea for 271 million years, and isopods have colonised the depths on multiple occasions over this period. These findings are not consistent with the hypothesis that the deep-sea fauna became extinct during the anoxic events of the Mesozoic.

By Luana Lins

A new study finds evidence that deep-sea creatures survived periods when the oceans contained little or no oxygen.

Luana Lins is a PhD candidate at the University of Sydney, and works in collaboration with the Australian Museum.

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The deep sea is one of the largest environments on Earth. This environment is defined as the part of the ocean that is below a depth of 200 metres, where in general a break in the continental shelf marks the start of the continental slope.

Oceans cover 70% of the Earth’s surface, with the deep sea making up 90% of the volume of the oceans. Possibly because of its impressive dimensions and remoteness from terrestrial life, the deep sea has fascinated human beings for a long time. But discovering the curious creatures of the depths took a while, especially because the deep sea was long believed to hold no life. Because of the crushing pressure and the darkness of the abyss, where plants could not grow as a food source, it was generally thought that organisms could not survive. In the early 19th century, however, sea-going naturalists showed that life was indeed abundant in the depths.

The late 19th century saw the first scientific marine expeditions, of which the Challenger expedition was perhaps the most famous. This expedition sailed from England in 1872 and discovered many new animals and collected data on a wide range of ocean features, including the geology of the seafloor, before returning in December 1876.

Nowadays, the deep sea is known for its high diversity of animals, which have many intriguing body forms that are not found in the shallow...

The full text of this article can be purchased from Informit.