Surveying and mapping the seafloor of our vast marine estate
Australia claims one of the largest marine jurisdictions in the world, a territory twice the size of our land mass. Defined by our Exclusive Economic Zone (EEZ), Australia’s jurisdiction stretches around the entirety of the Australian continent, along the coast of the Australian Antarctic Territory and around our offshore islands. Many of these islands are remote: Christmas Island and the Cocos (Keeling) Islands to our northwest, Heard and McDonald Islands to the southwest, Macquarie Island to the southeast and Norfolk Island to the northeast.
With its EEZ totalling over 13 million km2, Australia has sovereign rights over a vast area of ocean, along with the natural resources contained within these waters, sediments and seabed. An understanding of these resources is vital for our success in managing and protecting their prosperity. This knowledge is also vital for claims to increase our maritime territory.
Emphasising the importance of our marine estate, Australia’s marine industries are predicted to contribute $100 billion each year to the Australian economy by 2025.
Protecting our maritime sovereign, security and safety is contingent on having access to high quality information about the structure, composition and origin of our seafloor. This supports the effective management of our vast marine estate. It also improves our ability to predict and protect coastal infrastructure and communities from the impact from marine hazards such as volcanic and seismic activity, underwater landslides and tsunami. Having accurate seafloor mapping and charts are also essential for safety of navigation for maritime trade and recreational users.
However, only a small percentage of Australia’s vast marine estate has been surveyed in any detail and mapped to a modern standard. This is despite significant mapping efforts by various agencies in Australia. Surveying and mapping our marine estate is a significant priority for Australia, a marine nation that is sustained and protected by the oceans that surround it.
A national capability for advanced seafloor mapping and surveying
RV Investigator is a state-of-the-art research vessel that enables multidisciplinary study of the ocean anywhere across our vast marine jurisdiction. The vessel’s range (up to 10,000 nautical miles) and endurance (up to 60 days) allow it to conduct geoscience research in the farthest reaches of our marine estate and beyond. Combined with the vessel’s extensive suite of scientific equipment and systems, along with teams of specialist seagoing technical staff to operate them, this enables researchers to collect both high-quantity and high-quality data from our oceans.
RV Investigator provides researchers with an array of capability to undertake fundamental geoscience research to help Australia define, manage, secure and expand its marine jurisdiction. Attached to the ship’s hull is a steel housing called a gondola. This contains advanced sonar technology called multibeam echosounders (MBES) for mapping the seafloor. The ship has three discrete systems, two of which are permanently mounted in the gondola – Kongsberg EM 122 and Kongsberg EM 710 systems – and one portable system which can be added to the drop keel – Kongsberg EM2040c system.
The Kongsberg EM122 is a deep-water bathymetry (seafloor mapping) system which offers high resolution mapping from 300-400 m to full ocean depth. The Kongsberg EM710 is designed for acquiring high-resolution, relatively shallow bathymetry and backscatter data on the continental shelf. Optimal operation is up to 600-700 m depth, but the system can work to a maximum depth of 2000 m. The Kongsberg EM2040c is a portable system which can be fitted to the vessel drop keel to capture high resolution imagery in shallow water up to 600 m.
RV Investigator also has advanced equipment to probe the composition of the seabed and below. A sub-bottom profiler, contained within the gondola, sends sonar pulses that can penetrate up to 100 m into the seabed to reveal the geological structure below. A gyroscopically stabilised gravity meter on board lets researchers study large geological features in the earth below the seafloor. Equipment can also be towed behind the ship to collect geoscience data. Towed magnetometers can be used to find magnetic anomalies created by minerals such as those containing iron. These systems can also assist in locating shipwrecks. Similarly, the ship can also deploy side scan sonar that can be towed within a few metres of the seafloor to provide detailed images of seafloor habitats and features.
RV Investigator has a small-scale, high resolution seismic acquisition system which is used for research purposes. The system, which was paid for by Geoscience Australia, includes two seismic compressors, two seismic air gun bundles and data acquisition software. The seismic acquisition system is designed to image sub-seabed geological structures up to 2000 m deep. For Australian researchers, this system is vital and fills a data gap between large commercial seismic systems and sub-bottom profilers (which gather data up to 100 m into the seafloor).
Further research can be undertaken by taking samples of the sea floor and seabed, and the vessel has a variety of sleds, dredges and corers available for this.
A Sherman sled can be towed behind the ship to collect biological samples, sediment and small loose rocks. The Smith McIntyre grab works like two hands scooping up a sample of the top few centimetres of sea floor. The multi-corer collects mud and the small animals living in the first 50 cm of the sea floor with little disturbance. It has six thick polycarbonate tubes that can collect small cores. The long piston corer can take samples of other sediments up to 24 m in depth.
Cores must be kept at 4°C for long term archival and storage and the vessel has a variety of cool rooms and freezers. The vessel also provides geoscientists with generous workspaces on board, including General Purpose Laboratories and an Operations Room for coordinating scientific operations.
Since commissioning in late 2014, RV Investigator has delivered 22 voyages with a primary focus on geoscience research. However, every voyage includes geoscience data collection via the vessel’s underway data systems, regardless of the primary research project. These voyages contribute to global programs and are highly collaborative, delivered by Australian research partners and their international collaborators.
Significant contributions by RV Investigator to geoscientific efforts include:
- IN2020_V01: Development of William’s Ridge, Kerguelen Plateau. Led by the University of Tasmania, researchers mapped 100,000 km2 of seafloor and collected geological samples from two regions of remote seafloor territory southwest of Australia to support a submission to the United Nations Commission on the Limits of the Continental Shelf to extend Australia’s marine jurisdiction on and around William’s Ridge, Kerguelen Plateau.
- IN2019_V07: Hydrographic and maritime heritage survey of Bass Strait. Led by Australian National Maritime Museum and in collaboration with the Australian Hydrographic Office, researchers undertook a seafloor survey in Bass Strait to assist in facilitating safe navigation for shipping as well as successfully locating the wreck of SS Iron Crown, a 100 m Australian ore freighter lost for 77 years after being sunk by the Japanese during WWII.
- IN2016_V01: HEOBI: Heard-Earth-Ocean-Biosphere Interactions. Led by the Institute for Marine and Antarctic Studies (UTAS), researchers collected geological samples and mapped 1000 km2 of uncharted seafloor around Heard and McDonald Islands, locating hydrothermal vents that indicate active seafloor hydrothermal systems and baring rare witness to an eruption of Heard Island’s Big Ben, Australia’s only active volcano.
- IN2015_C01: GAB deep water geological and benthic ecology program. Led by CSIRO, researchers collected data and samples to significantly expand the sparse data available for the deep water of the Great Australian Bight (GAB) to provide a more detailed understanding of the geological evolution of the southern margin of Australia.
Importantly, all voyages of RV Investigator collect continuous geoscientific data via the vessel’s underway data collection capabilities. The MBES systems on board continuously collect bathymetric data while the vessel is underway. The data collected makes a substantial contribution to aggregated national and global datasets including AUSSeabed.
The MNF Publications database records 20 journal articles primarily related to geoscience research delivered by RV Investigator (representing approximately 8% of all articles and reports). While likely an incomplete record of all research publications related to research delivered by RV Investigator, the impact on knowledge creation is substantial. Insights and research findings are published in many of the world’s leading scientific journals. Commonly, publications from research delivered have a high diversity in co-authorship, demonstrating engagement between Australian researchers and the global scientific community. This signals that the research being conducted is of global importance.
Significantly, in the absence of RV Investigator, some areas of research would remain understudied.
Beyond the research, there is a significant contribution to training and development of future generations of marine researchers on RV Investigator voyages through student participation, as well as education and outreach activities. Supporting such activities is one of the strategic pillars for the operation of the Marine National Facility (refer MNF2030).
Collecting continuous high quality data to boost Australia’s seafloor surveying efforts
The geoscience research delivered by RV Investigator is globally significant and provides data to address the grand challenges being faced by Australia, our region and globally. The data collected provides significant insights about the composition, structure and origin of our seafloor, some of which may have remained unstudied without this capability. Similarly, the geoscience data collected provides productivity, efficiency, and quality benefits to commercial activities, including offshore development, fishing and aquaculture.
Emphasising the importance of the seafloor mapping undertaken by RV Investigator, a recent independent impact assessment by RTI International estimated median benefits of $2.7 billion through FY2029/30 from our seabed mapping.
These data address key challenges we face including building resilient and valuable environments, protecting food security and quality, and safeguarding maritime security and sovereignty.
Using our capabilities, researchers have delivered geoscience research to:
- Improve seafloor mapping and charting for safe navigation. The geoscience data from many voyages is provided to the Australian Hydrographic Office (AHO) where it is used to update nautical charts. This provides for safe surface and subsurface navigation for vessels. The vessel has also undertaken several voyages for the AHO. These voyages have concentrated on surveying primary shipping routes within Bass Strait to a modern standard.
- Better understand past ocean and climate conditions, and marine ecosystems. Marine sediments offer a long-term record of past ocean and climate conditions, as well as past marine ecosystems. RV Investigator’s deep sea sediment sampling capabilities have allowed researchers to help fill gaps in our climate record and study previous interactions of ocean and climate. Further, through analysis of the marine life and DNA in these sediments, researchers have also been able to investigate past ecosystems over large timescales. This understanding increases our ability to model and predict the impact of future changes and better prepare for the future.
- Provide vital data for defining and understanding the reach of Australia’s marine jurisdiction. A 2020 voyage explored the ancient rifting, breakup, and separation of tectonic plates in the Indian Ocean. Over 100,000 km2 of seabed were mapped as part of an effort to determine whether an area the size of Switzerland should be considered as part of Australia’s marine territory. Data were collected for a future submission to the United Nations Commission on the Limits of the Continental Shelf. If judged eligible, it could add 40,000 km2 to the continental shelf recognised as Australia’s marine territory.
- Locate significant maritime heritage sites including shipwrecks and submerged Indigenous landscapes. RV Investigator has been successful in several surveys for shipwrecks of national significance. These collaborative efforts with state and national heritage agencies, along with volunteer maritime heritage groups, have resulted in the location of SS Macumba in 2017 and SS Iron Crown in 2019. There have also been several shipwreck discoveries made during routine mapping operations. The discovery of these shipwrecks provides economic, environmental and societal benefits.
- Make significant contributions to national and global seafloor mapping efforts such as AUSSeabed and GEBCO. RV Investigator’s combination of seafloor mapping systems allows high quality and quantity data to be collected from any depth in our marine estate. These data, which are continuously collected by the vessel both in targeted surveys and underway data collection, make a significant contribution to aggregated bathymetric data sets for various mapping efforts. Globally, the data we collect contributes to GEBCO, the General Bathymetric Chart of the Oceans. Within Australia, we are a significant contributor to AUSSeabed, a collaborative effort led by Geoscience Australia with the aim of improving the quality, discoverability and collaboration of seabed mapping in our region.
- Assess and plan to mitigate risk from submarine-landslide generated tsunami along Australia’s coastline. Research delivered by RV Investigator has helped increase understanding of the causes and consequences of the submarine landslides along Australia's coastlines. This research, conducted by both RV Investigator and its predecessor, RV Southern Surveyor, helps ensure that coastal planners and emergency managers are better informed about the hazards facing Australian coastal communities.
The geoscientific data streams collected by RV Investigator provide tangible real-world benefits. These are used by researchers, industry and other stakeholders to inform their operational activities and decision making. Seabed mapping provides productivity, efficiency, and quality benefits to commercial activities. Offshore development, fishing, and aquaculture all benefit from increased knowledge of the seabed. Most benefits are indirect, in that they do not directly provide revenue to commercial entities. Rather, they improve processes and support activities that increase efficiency, reduce risk, increase yield, or support site selection. Ultimately, these data play a critical role in evidence-based decision making, resource and risk management strategies, and offshore activities.
Importantly, all data collected on voyages and through MNF capability, whether from CSIRO or user supplied equipment, are made freely available for the use and benefit of all. Data can be accessed through a CSIRO data portal where it can be discovered, accessed, used and reused. Data is also served through various external platforms such as the AUSSeabed Marine Data Portal. CSIRO engages directly with various end-users of our data to ensure data is accessible and meeting their needs.
This ensures the greatest benefit is delivered from every voyage and from every unit of data collected by RV Investigator.
- Armbrecht, L.H. (2020). The potential of sedimentary ancient DNA to reconstruct past ocean ecosystems. Oceanography 33(2):116–123, https://doi.org/10.5670/oceanog.2020.211.
- Armbrecht, L.H. et al. (2021). Ancient DNA and microfossils reveal dynamics of three harmful dinoflagellate species off Eastern Tasmania, Australia, over the last 9,000 years. bioRxiv preprint. https://doi.org/10.1101/2021.02.18.431790
- Puga-Bernabeu, A. et al. (2022). Submarine landslide morphometrics and slope failure dynamics along a mixed carbonate-siliciclastic margin, north-eastern Australia. Geomorphology Volume 403, 108179. https://doi.org/10.1016/j.geomorph.2022.108179