Seamounts, Canyons & Reefs of the Coral Sea

Characterizing the Canyons
The Great Barrier Reef (GBR) is one of the world’s best-known reef systems, however its deep reef and canyon ecosystems are largely a mystery. Scientists will employ a suite of advanced marine technology – including unmanned aerial vehicles, autonomous underwater vehicles (AUV), and remotely operated vehicles (ROV) – to collect and analyze geological and biological data of the GBR and the adjacent Coral Sea Marine Park. R/V Falkor’s advanced multibeam systems will be used to map the structure of the reefs, canyons, and seamounts, illuminating their formative processes. In parallel, ROV SuBastian will collect samples, sediment cores, and high-resolution imagery of the deep canyons and reefs that extend down to 2,500m. ROV SuBastian will also be outfitted with a high-resolution camera from JAMSTEC to image plankton throughout the water column. Seabed environments in less than 200 m depth will be imaged using the advance camera system on the University of Sydney’s AUV Sirius.
This data will greatly improve understanding of the sedimentary processes that influence biodiversity patterns, including how canyons may provide a pathway for sediment to travel from coastal and shelf water to deep filter feeders. The deep and irregular canyon topography also leads to direct upwelling of nutrient-rich deep waters, including Subtropical Mode Water in the northern GBR. ROV SuBastian’s sensors will be used to track water mass changes, helping to identify the impact of upwelling of these cooler waters onto the shelf.

Understanding Ecosystems and Informing Conservation
An important goal of the expedition is to study the mesophotic and deeper reefs in the region. This work will highlight the importance of high-relief features globally for marine biodiversity conservation and provide a template for a survey approach to effectively inform management of high-value, remote areas. These deeper reefs may play a key role by providing a refuge for surface and other marine species that are negatively affected by climate change. Identifying the role of deeper reefs is crucial as bleaching events in the GBR and surrounding surface reefs are increasing as the ocean warms.
The expedition will create a rich dataset of seafloor biological and geophysical data enabling researchers to understand the habitat provided by large-scale seabed features in the region. The expedition will provide key insights that will determine if various geologic features host different biological communities, and if there are species endemic to the region. Furthermore, the information resulting from the expedition will greatly improve knowledge of these highly-valued ecosystems and is essential for their responsible management and protection.