Snapshots of the deep shed light on hydrocarbon seeps

June 09, 2025

Mizzou Engineers have developed a low-cost mobile technology to study naturally occurring gas leaks beneath the ocean’s surface.

A submerged RPiPIV system — *Unlike most conventional PIV, RPiPIV can be submerged underwater and moved.*

At Mizzou Engineering, we push boundaries in the classroom, the lab and in the real world to explore new possibilities. That’s the drive behind Mizzou researchers who have developed a practical, technological solution that will drive further discoveries in some of the most remote environments on Earth.

Natural hydrocarbon seeps — places where gases leak from the seafloor — occur all over the world. These seeps release streams of tiny gas bubbles into the ocean, feeding deep-sea microbes that rely on chemicals like methane.

Binbin Wang, William Andrew Davidson Professor in the Department of Civil and Environmental Engineering, has spent years researching hydrocarbon seeps.

“Studying this phenomenon gives us better understanding of deep-sea ecosystems as well as how methane is transported in ocean waters,” he said.

To measure how much gas is leaking out and whether it reaches the ocean surface, Wang had to access one of the most hard-to-reach places on the planet: the ocean floor. Once there, he could observe those tiny gas bubbles, but he needed technology to do so.

Up to now, researchers have been able to study small particles in water using particle image velocimetry (PIV): A laser lights up the particles, a camera takes a snapshot and software tracks how those particles move.

But PIV is typically not submerged. Wang needed to find a way to get this bulky, expensive technology to the ocean floor and back.

Wang and his team set out to create a new, underwater PIV system. Called RPiPIV, the system is powered by a Raspberry Pi — a low-cost computer about the size of a credit card. Unlike conventional PIV systems, RPiPIV can be tethered to a robot submarine for live monitoring or set up on the seafloor, making it easier to collect data on hydrocarbon seeps. Wang describes the system in an article published in Limnology and Oceanography: Methods.

“The key benefits of RPiPIV are its portability and underwater capability,” Wang said. “It’s also much cheaper than conventional PIV because it uses off-the-shelf parts like a consumer laser and camera and the Raspberry Pi,” Wang said.

Wang and his team tested RPiPIV in the laboratory before taking it on a research cruise in 2024 and deploying it at a depth of about 1,800 feet, becoming the first to study hydrocarbon seeps using an underwater PIV system.

Comparison between a conventional PIV system (top row) and RPiPIV (bottom row). Images (a) and (d) are raw photos of bubbles rising through the water. In (b) and (e), the bubbles are removed, leaving only the movement of the water. Images (c) and (f) show the direction and speed of the water (yellow arrows) moving around the rising bubbles (black spots). Longer arrows mean the water is moving faster.

The results were promising, if not perfect, and Wang is encouraged.

“There’s room for improvement,” Wang said. “The laser isn’t as focused or powerful as professional ones, and the camera is slower. But RPiPIV can go places conventional PIV can’t.”

The technology behind RPiPIV is currently under review for a provisional patent application. Wang is interested in pursuing a commercial patent and envisions researchers employing the low-cost, versatile technology to study flows in lakes and streams.

“Sometimes the simplest solutions are the best,” Wang said. “By taking a practical, DIY approach to a complex technological puzzle, we’re accelerating the pace of discovery at that bottom of the sea, which can have an impact on life all over the planet.”

Mizzou Engineers are exploring new possibilities in our innovative centers and labs. Learn more about our research!