Underwater robots take to the deep to map unexplored oceans

Autonomous Underwater Vehicles (AUV) from the University of Sydney will be taking a deep dive in the oceans surrounding Norfolk Island to collect high-resolution seafloor images. The images will then be used to create three-dimensional underwater models of these unique reef ecosystems and marine habitats.

The AUV will be deployed by a team led by Professor Stefan Williams from the Australian Centre for Robotics (ACFR) at the University of Sydney.

The AUV is equipped with high-resolution stereo cameras and a suite of navigation sensors that allow it to capture tens of thousands of images of the seafloor at targeted sites around the island. The vehicle will be mapping thousands of square metres of the sea floor around the island to provide scientists with insights into the distributions of key benthic species (animals that live on the seafloor and in the depths of the ocean). The team will also be using machine learning based methods for classifying the imagery and looking for interesting or unusual species.

Underwater robots are essential for ocean exploration as they can safely navigate deep sea environments that are inaccessible for divers. The robots become underwater explorers, and the hands, eyes and ears of scientists.

“It’s the first time that parts of the seabed in the Norfolk Ridge will be imaged in this detail,” said Professor Williams, who is a Professor of Marine Robotics at the University of Sydney. “The AUV’s visual and acoustic sensors will gather data to generate high resolution 3D models of the seabed and marine habitat. We’re excited to support the expedition and see what our environmental survey of the area will uncover.”   

Norfolk Island is an external Australian territory, located in the Tasman Sea between Aotearoa, New Zealand, and New Caledonia, 1600km northeast of Sydney. An isolated volcanic island which spans tropical and temperate ecosystems, the region hosts diverse species of animals and plants, which the expedition will document alongside the effects of a dramatically changing climate.

The ACFR have been developing and deploying AUVs to help expeditions collect data over sensitive tropical and temperate reefs and other ocean environments, including an archaeological survey in Greece that unearthed a 2000-year-old skeleton in a shipwreck, thanks to underwater mapping technology.

This second phase of the Norfolk Island scientific expedition is led by the Australian Museum Research Institute (AMRI) working in collaboration with the University of Sydney, Parks Australia and the Museum of New Zealand Te Papa Tongarewa, and the Auckland War Memorial Museum, alongside the local Norfolk Island community. The current expedition to Norfolk Island builds on the terrestrial survey undertaken by AMRI Scientists in 2022-2023.

On this expedition, scientists will undertake shore and vessel-based activities to collect fish and marine invertebrates, such as corals, crabs and molluscs, as well as algae, to expand knowledge of the marine environment. A team of educators will also take part in an education program at the Norfolk Island school.

Director and CEO, Australian Museum, Kim McKay AO, said scientific expeditions of this scale were pivotal to the continued monitoring, protection and understanding of diverse and isolated bioregions, like Norfolk Island, which are particularly vulnerable.

“For nearly two centuries, the Australian Museum has conducted expeditions to document, collect and examine information on the habitats of our region and beyond. From this we have developed one of the most valuable natural science collections in the world, which aids in international research and will be conserved for generations to come,” McKay said.

“This second expedition to Norfolk Island will focus on the marine environments native to the area and introduced fauna and flora, and will help to expand existing scientific records and collections, informing the future management of these regions.”

Acting Chief Scientist of the AMRI, Professor Shane Ahyong, highlighted the importance of prioritising field research and working closely with cross-sector colleagues with complementary research interests and expertise. 

“There is a huge amount of value in bringing together scientists from different research institutions to focus on a specific location of scientific significance, like Norfolk Island,” Professor Ahyong said.

“Norfolk Island is a key oceanic stepping stone for species between tropical New Caledonia and temperate New Zealand, making it an important bellwether location for detecting species movements and climate change effects. In this return trip, the team will build on the knowledge we developed during the Norfolk Island Terrestrial Biodiversity Survey and the archaeological excavations that took place in 2022.”

The first expedition was a terrestrial survey, focusing on animals, such as rats, bats, lizards, insects, birds, and snails. This involved setting up mist-nets to study the diverse aerial fauna, and soil sifting and trapping to discover spiders, insects and other invertebrates. An archaeological dig uncovered two adzes (stone axes) and hundreds of flakes dating from pre-European Polynesian settlement.

Head of Natural Sciences at Auckland Museum, Dr Tom Trnski, said the expedition is integral to understanding patterns of marine biodiversity in the region. In addition to the scientific surveys, the Norfolk Island local community has been invited to engage with scientists through education activities with the Norfolk Island Central School and a range of programs and events to learn about the expedition.

“This expedition has been a priority for the Australian, Auckland and Te Papa museums as Norfolk Island is a major gap in our knowledge,” Dr Trnski said. “This is an important opportunity to document the marine biodiversity in the southwest Pacific region so we can support the understanding of the biodiversity connections among the islands in the region and help predict dispersal pathways in a changing ocean environment.”.