One of the main missions of the Deep-Sea Research Centre is the application of seafloor acoustics for mapping the ocean floor. Mapping the seafloor is a fundamental mode of observation used in oceanographic research and serves as a critical component for understanding marine ecosystems and guiding informed ocean management decisions.
Although 23.4% of the seafloor of the world ocean is mapped to a high resolution, these mapped areas are mostly located along the continental margin, and we live in surprising ignorance of the deep ocean–the largest habitat for life on earth. We are committed to expanding our understanding of the deep ocean by mapping the ocean floor, discovering new species, assessing marine biodiversity, and charting deep-sea habitats. We specialise in abyssal (3,000-6,000m) and hadal (6,000-11,000m) depths representing the deepest 70% of the oceans, the most extreme marine frontiers.
Our seafloor mapping team oversees the acquisition, processing, visualization, and management of the vast amounts of seabed data acquired by Kongsberg’s EM124 and EM304 multibeam echosounders (MBES), installed in RSV DSSV Pressure Drop and RV Pangaea Ocean Explorer during our voyages. The EM304 and EM124 not only record the full-depth topography of the ocean but also document the backscatter (acoustic return intensity) and water column data. Backscatter is what we use to determine the type of material or sediment on the seafloor, and the lighter value return normally indicates a harder seafloor, such as a rocky area, whereas lower values indicate soft sediments like silt or mud.
The datasets are be processed in QPS’s state-of-the-art software packages of Qimera, Feldemaus and FMGT. The products give us a window into the ocean depths and help us to understand some of its secrets. The maps are then used to inform our work multiple areas including seabed geomorphological classification, substrate characterisation, habitat mapping, physical oceanography, marine ecology, and marine national park assessment and protection.
Our seafloor mapping products are made available to AusSeabed and GEBCO to contribute to national and international mapping initiatives. Currently, our focus is to increase the seafloor mapping of abyssal and hadal depths, particularly in the Indian Ocean. We are currently working on data from the Diamantina Fracture Zone, Wallaby-Zenth Fracture Zones, and the Wallaby-Cuvier Escarpment.
Approximately only 23% of the ocean floor is mapped to a high resolution. Our team has access to two research vessels, DSSV Pressure Drop and Pangaea Ocean Explorer. Pressure Drop is equipped with a Kongsberg EM124 multibeam echosounder and the Pangaea with an EM304. One of the most important products we can get from high-resolution bathymetric data is the unprecedented seascape geomorphology at an unprecedented level of detail.
As different geomorphic features (e.g., seamounts, deep-sea ridges, steep cliffs, etc.), can condition a number of environmental characteristics, such as exposure to currents and waves, nutrient availability, substrate types, erosion, or sediment deposition, they often provide a range of spatiotemporal influences on the habitat suitability of an area for benthic fauna. Therefore, characterising seafloor geomorphology has significant importance in understanding the bio and geodiversity of the hadal trenches.
Terrain attributes (such as seafloor slope, Bathymetric Position Index (BPI at fine and broad-scales), aspect and terrain ruggedness) derived from bathymetric data could reveal the three-dimensional geomorphological characteristics of the seafloor. The backscatter data, on the other hand, are mainly used to gain insight into the seafloor sediment composition. Integration of these datasets with ground-truth information (i.e., videos, samples), could be used to segment the seafloor into different habitat classes. The outcome of this work has implications for how hadal conditions shape, assemblage and interact with different deep-sea biological communities. This will benefit the policymakers (marine spatial planning and establishing marine protected areas) as well as raise awareness of the marine environment among the community.
In addition, detailed seafloor geomorphology also reflects the morpho-tectonic evolution of the subsurface and thus helps us to understand how the modern seafloor is shaped and how the mechanism that how sediments are transported to the hadal trenches. Currently, we use a number of existing GIS-based mapping tools to semi-automatically characterize the seafloor, and actively working on developing a machine-based classification toolset.
Much of our research focuses on ecology: the interaction of animals with one another and their physical environment over space and time. We use non-destructive video sampling techniques such as baited landers and manned submersibles to survey the distribution, relative abundance and diversity of deep-sea organisms. Presently, our core ecological projects focus on fishes, benthic macroinvertebrates and crustaceans.
Manned submersibles provide the unique opportunity to undertake in-situ visual surveys of organisms to full ocean depth and provide the scientists onboard unprecedented access to explore multiple habitats in a single a dive. We use these vessels to understand the distribution and habitat association of organisms and they are a powerful tool to survey specific habitats in detail. For example, we have surveyed opposing sides of an active trench to understand how differences in geology, seafloor instability, and geomorphology contribute to the assemblage of macroinvertebrates and differences in their functional traits. We have also used submersible dives to explore the impacts of anthropogenic disturbances including the recovery of a large-scale anthropogenic sediment disturbance at 6500 m or how plastic bags alter the micro-topography of the seafloor at hadal depths and the implications for benthic organisms.
We utilise our fleet of full ocean depth rated landers and develop spatially balanced surveys to understand the distribution of species over different spatial scales from local within trench distribution to within and among oceans. Each lander is equipped with a high-definition video camera used to film organisms attending the bait. Using specialised software, video analysts document the incremental increase in the relative abundance of each species whilst the lander is soaking on the seafloor. These data are accompanied with environmental data collected using CTDs on the lander and multibeam echo soundings to construct species distribution models. We often include animal traps on the landers which, when successful, provide rare samples of deep-sea organisms. Specimens allow us to confidently identify animals captured on video footage and provide an opportunity to discover new species and undertake phylogenetic analyses to understand population ecology, evolution and speciation.
Video cameras and fish traps attached to our fleet of baited landers allow spatially balanced surveys of hadal trenches and to understand the global distribution and connectivity of hadal snailfish and cusk eels.
Australia has the third largest Exclusive Economic Zone in the world and 40% of this is protected in a network of Marine Parks. We recently described the current protection of Australia’s deep-sea and found 56% of the area with Australia’s Marine Parks is deeper than 3000m. Despite this, Australia’s local capacity to undertake deep-sea research has been limited historically. Much of Australia’s deep-sea is also located in the Indian Ocean and at the doorstep for our research group. This, coupled with our initiative to build full ocean depth landers has allowed us to collaborate with Parks Australia to explore and document deep-sea habitats in Australian Marine Parks.
We recently explored the deepest location offshore mainland Australia in South-West Corner Marine Reserve as part of an ongoing project to explore and document benthic habitats and mobile organisms in Australia’s deepest Marine Parks. This program will expand up the Australian coastline and include two long-term observatories located in the South-west and North-west Marine Parks Networks. These observatories will collect oceanographic and biological data continuously while they remain on the seafloor for more than one year. These data, coupled with ongoing lander monitoring provide critical knowledge required for the long-term management of deep-sea environments off Australia and internationally.
For our statement against deep-sea mining, please see Professor Jamieson's statement on Minderoo.org.
Our centre aims to expand on our current knowledge of the diversity and demography of hadal fauna through integrative taxonomy, sample beyond single, isolated deep-sea features to examine how population-level dynamics are shaped by topography, depth and geography, as well as to expand our research from barcoding studies to multi-locus phylogenomic studies that can investigate the molecular evolution of our collected hadal fauna. Together, this work will allow us to understand how these geomorphologically complex hadal features have facilitated in-situ speciation events because of long-term geographic isolation or illuminate multi-ocean distributions.
The order Amphipoda, particularly scavenging amphipods, has emerged as a model taxon for understanding drivers of diversity and ecology across the hadal zone as they can be readily and consistently recovered with baited landers. We are currently addressing questions of genetic connectivity, species diversity and phylogeographic structure between multiple deep-sea features and from various hadal and abyssal amphipod species and genera.
Our oceanographic research involves understanding the physical environment of the hadopelagic using full-depth CTD (Conductivity-Temperature-Depth) measurements, current meters and other oceanographic sensors. Synthesis of this oceanographic data contributes to understanding the ecology of trenches and the hadal zone.
Over the next few years the Deep-Sea Research Centre’s oceanography focus will be on mixing and circulation surrounding trenches including bottom water ventilation, water-mass characteristics, population connectivity of species and their linkages to environmental conditions such as global abyssal circulation, and long-term monitoring of bottom currents, water properties and sediment flux via permanent observatories in WA Marine Parks.
Because it the ocean is uninhabitable to humans, it is resistant to established forms of human knowledge-making and therefore understanding. This is all the more pertinent when it comes to the deep sea, which is often disregarded as a place entirely irrelevant to human life. Guided by a cynicism towards anthropocentrism, we draw upon the environmental and blue humanities to consider how the deep sea relates to current conversations around material feminisms, multispecies ethnography, and tentacular thinking.
By incorporating the (post)humanities into the rhythms of our multidisciplinary research centre, we hope to overcome what we perceive is a phenomenological gap between humanities scholars and field scientists. We address the multitude of calls by critical theorists and object-oriented ontologists to stop thinking about the ocean in terms of its flat construction in the discourses and instead imagine it as a place with not only depth, but also rhythmic motion. In working across these disciplines, our work investigates the role of fear in affecting public perception of the deep sea as well as the phenomelogical concept of the deep sea itself.
For the vast majority of people, interaction with the deep sea is limited to its representation in popular culture. This includes natural history documentaries, news articles, video clips, and fiction such as horror film, literature, and children's edutainment. However, the deep sea is often universally represented as a scary and unknown space, which is not conducive to meaningful connections to the largest habitat on earth. This in turn affects support for conservation and effective stewardship of the deep oceans.
Our investigation considers the representation of the deep sea across a broad range of literature and media, both fiction and nonfiction, fantasy and realism. This includes Blue Planet, Aliens of the Abyss, SpongeBoB Squarepants, Octonauts, 20,000 Leagues Under the Sea, the work of HG Wells, the work of Guillermo del Toro, the work of HP Lovecraft, and deep-sea video games. By utilising posthumanist, ecofeminist, and poststructuralist reading practices and critical discourse analysis, we consider the sensationalised and scary ways in which the deep sea is constructed in the popular imagination, and how it compares to the lived experience of scientists.
We are also interested in mythological sea monsters and how they embody fears about the natural world. What exactly are sea monsters and why do they recur across so many cultures? What do they say about the cultures from which they were imagined? What exactly makes them scary?
Our centre also works with writers, poets, and artists to produce original and scholarly creative work that engages with the deep sea and the way in which it is imagined, constructed, and studied.