The Great Australian Deep-Sea Coral and Canyon Adventure

An Expedition of Epic Proportions
The area along the shelf-edge of southwestern Australia holds a number of unexplored submarine canyons that face the Southern Ocean region. The waters above the Bremer Canyon are known to be a hotspot of biodiversity that includes large marine mammals and seabirds, which has led to its establishment as a Commonwealth Marine Reserve. It is renowned for attracting congregations of the largest seasonal populations of killer whales in the Southern Hemisphere, which has become a significant tourist attraction.

Characterized by its steep-sided, interconnected system, this unexplored canyon offers great prospects for the discovery and exploration of new life within its deep-water habitats. In addition to genuine frontier exploration, key species, such as deep-water hard corals, are highly prized environmental archives that can provide invaluable ‘windows’ into the recent and geological past for understanding both long-term natural climate variations and how anthropogenic-driven climate change is impacting the deep oceans. Corals from the southwest Australian submarine canyons are especially significant given their proximity to the all-important Southern Ocean. The waters formed in the Southern Ocean feed all major ocean basins so play a central role in driving the global ocean-climate system.

The team is advancing the findings of their successful 2015 expedition to Perth Canyon, which offered significant optimism for finding prospective habitats, new species, and particular coral types suitable for proxy applications. In all, the team plans on visiting three submarine canyon systems: Bremer, Leeuwin, and Perth Canyons.

Protecting Corals and Telling a Story
A primary focus will be to sample anticipated living and fossil deep-water corals from this region. The skeletons of these organisms will be used to reconstruct recent and long-term ocean environmental records as there are large gaps in “climate proxy” records, and instrumental ship-based data is very limited covering only the past few decades. The coral skeletons can provide continuous records of important environmental variables, including fluctuations in the temperature of these deeper oceans, pH, nutrients, and dissolved calcium carbonate concentrations. These records can span decades, centuries and even millennia, and help to elucidate not only changes in the ocean-climate system but also the inherent vulnerability of corals and other calcifiers to extreme conditions.

In addition to characterizing a genuine frontier, the data collected from these deep-water corals and their surrounding environments will allow scientists to develop an understanding of the physical and temporal changes occurring in the Southern Ocean. Only recently has it been realized that the formation of the deeper water masses of the Southern Ocean hold the key to unlocking the response of the global ocean-climate system to both climate and environmental change. The acquisition of baseline data obtained from these deeper water masses of the canyons thus provides a unique window into both the recent and geological past. The answers found can have major implications both regionally and worldwide, such as helping to predict the effects on deep-sea calcifiers and their ecosystems, and for modeling future climate change scenarios and their potential impacts on society.