Geomorphology of the South-east Marine Region of Australia

The environment in the South-east Marine Region is exceptionally diverse. It encompasses shallow shelf, slope and deep water ecosystems that provide important habitats for a variety of bird and sea life.

Geologically the South-east Marine Region has been partly shaped by the catchments of Australia's major river systems from Victoria, Tasmania and the Murray-Darling Basin which take in a land area in excess of 1.2 million square kilometres. These river systems provide inputs into coastal ecosystems and have helped to shape underwater features at times of lower sea levels.

Examples of this are the canyon structures at the eastern end of Bass Strait and the spectacular Murray Canyons, a geological marvel bigger than the Grand Canyon. The water depth in the region varies from the vast shallow expanse of Bass Strait, averaging 60 metres deep, to the Hjort Trench, near Macquarie Island, where the sea floor lies 6700 metres below the surface.

Other key geological features of the Region include the upper continental shelf, where water depths are generally less than 200 metres, seamount structures off southern Tasmania, the sunken continental shelf known as the South Tasman Rise south of Tasmania, and the steep continental slope.

The South-east Marine Region has many unique and fascinating geomorphological features that shape the landscape, alter the currents and create places where animals and plants can live. These features include submerged mountains, canyons and ridges set against the vast, flat expanse of ocean floor. Much is yet to be discovered within this underwater 'landscape'.

The following map and table illustrate the geomorphic features in South-east Commonwealth Marine Reserve Network.