We have developed the first baseline picture of seafloor marine life deep in the Great Australian Bight, transforming the region from having Australia’s least known to best-known deep-sea marine communities.
Understanding seafloor communities in the Bight
Benthic (seafloor) habitats are found in the mid- to lower continental slopes (1000 to 3000 metres depth) and play a vital role in deep ocean ecosystems – engineering habitats and transferring energy up the food chain. However, information on these communities in deep areas of the Bight has been limited.
Scientific knowledge on this region’s diversity, distribution and ecology is fundamental to assessing the potential impact of future human activities to help manage the environment, economic and social values of the region.
Exploring the depths
We worked with the South Australian Research and Development Institute to conduct the deepest systematic surveys that have been taken in Australian waters to examine the composition and distribution of benthic communities in the Bight.
The study identified key habitats, communities and species, developed maps of distributions, and methods for monitoring future changes in status.
By using 200 multi-corer samples taken at 30 sites, we identified 277 species new to science. We also discovered 887 species new to the Great Australian Bight.
This research has provided ground-breaking information on deep-sea communities, and transformed the Bight into one of the best understood deep-sea regions in Australia.
Hundreds of new discoveries from the seafloor
Sea-floor sampling led to the collection of 63,340 benthic invertebrate specimens, providing the first information on the composition, abundance and distribution in fauna, epifauna, fishes and microbes in the central Great Australian Bight's deep waters.
More than 44,000 specimens and 600 species of invertebrate epifauna were collected, with one quarter of these species being new records in Australian waters.
Abundance of organisms was related to depth, with a decrease in abundance in waters deeper than 400 m. Samples collected over time differed, indicating substantial variability over time. Sponges and echinoderms dominated the overall biomass and density.
This research provides new knowledge on marine life in this expansive ecosystem and establishes a significant legacy for future Great Australian Bight monitoring programs.