The Office of Naval Research (ONR) has funded a mathematician to advance acoustic technologies to map the uncharted expanses of the planet’s ocean floor. Part of the ONR’s Basic and Applied Scientific Research program, the three-year mission to explore Earth’s final frontier is expected to enhance the Navy’s anti-submarine warfare strategies and support ocean conservation efforts.
Enduring Mysteries Drive Goal to Map the Ocean Floor
According to the National Oceanographic and Atmospheric Administration, only 26.1% of the world’s ocean floor has been mapped with high-resolution technology. As a result, many of the structures and geological features of the deepest part of the world’s oceans remain a mystery.
Recent efforts to study the deepest parts of the world’s oceans have answered some of these questions while leaving many mysteries unsolved. Some unexplained mysteries include the search for interstellar fragments resting at the bottom of the ocean and the hunt for missing evidence of ancient climate change.
Earlier this year, an international team of geophysicists reported the discovery of a “lost world” at the bottom of the Pacific Ocean. Another effort found the source of a mysterious glow at the bottom of the Pacific Ocean that has stumped scientists for years, while a third team found glowing sharks in the ocean’s “Twilight Zone.”
glowing sharks
Researchers previously found a glowing shark in the ocean’s “twilight zone.”
Several other recent studies have found evidence of mysterious structures growing in deep-sea canyons, a 66 million-year-old space object impact crater, a previously undiscovered deep-sea predator, carbon-eating microorganisms, and even a complex ecosystem thriving in the blackness beneath the ocean floor. Unfortunately, the incredibly low temperatures, low lighting conditions, and extreme pressures in the deepest parts of the oceans have made further advancements incredibly difficult and costly.
“Mapping the seabed is a challenging endeavor due to the extreme conditions,” explained Mathematics Professor Eliza Michalopoulou, chair of the New Jersey Institute of Technology (NJIT) Department of Mathematical Sciences and the lead researcher of the ONR-funded effort “The immense pressure is crushing at depths like the Pacific’s Mariana Trench, for example, where it reaches over 1,000 times sea-level atmospheric force, making it difficult and costly to deploy submersibles for exploration.”
According to Michalopoulou, the most efficient and promising method for mapping the unexplored expanse of the ocean floor involves the ideal combination of sound and mathematics.
Using Sound to Unravel the Mystery
The process employed by the NJIT mathematician is called geoacoustic inversion. The technology uses hydrophones, a type of microphone that operates in the water. When sound waves are bounced off the ocean floor, the returning data collected by the hydrophones can reveal anything from bathymetry (meaning the ocean’s depth) to sediment density and sub-bottom layering.
The hydrophone pictured here is located within Gray’s Reef National Marine Sanctuary in Georgia. Image Credit: NOAA.
“By ‘listening’ to the ocean, we can analyze its properties and characteristics without the need to physically deploy extensive equipment into the depths of the vast underwater world,” Michalopoulou explained.
Still, the ocean is busy and active, filled with marine life, geological processes, ships, and submarines, all making their own sounds. Separating these acoustic signals requires complex mathematics if the researchers hope to get a clear picture of the ocean floor.
“We integrate this acoustic data with mathematical models to understand how sound interacts with the seabed,” the professor explained. “This helps us predict how signals — like those from submarines — travel through water and what they should ‘look’ like when received.”
Different Methods Yield Different Results
Although the process seems relatively straightforward, the challenge lies in selecting the correct mathematical models and methods. For example, one approach assigns known mathematical values to ocean currents and other oceanographic conditions, like sediment properties, while another treats these as unknowns. In most cases, models fed the same data can offer dramatically different results.
“Different methods can point to completely different structures in the seabed layers,” Michalopoulou said. “Understanding the properties of the seabed is pivotal for things like defense operations and environmental conservation, but we need to understand why these methods disagree to be confident in our data.”
mirror universe
Another barrier the researcher hopes to overcome with mathematics is that many conditions needed to perfect the models are still unknown.
“The problem is that the ocean floor is largely a mystery, and we usually don’t know the true properties of the seabed, so it is difficult to assess how well a given method performs in mapping it accurately,” said Michalopoulou.
Fortunately, the researcher says advanced mathematical models are becoming complex enough to create realistic simulations if enough values can be determined. This flexibility, she notes, “allows us to evaluate different mapping methods and understand their variability.”
Three-Year Mission to Map Earth’s Final Frontier
Michalopoulou’s project, “A Simulation Study for Assessing Accuracy, Uncertainty, and Consistency in Geoacoustic Inversion Across Methodologies,” has already commenced. If successful, the professor believes they will have gathered enough data on the varying approaches to move closer to creating a high-resolution ocean floor map.
“In three years, we expect to have thoroughly analyzed a wide range of approaches, assessing their accuracy, inherent uncertainty, and potential for real-time application,” she said. “The insights and conclusions drawn from this research will contribute to high-fidelity seabed exploration, ultimately enhancing the effectiveness of anti-submarine warfare strategies.”
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him onX,learn about his books atplainfiction.com, or email him directly atchristopher@thedebrief.org.