Sentinel oysters and other bivalve mollusks are now monitoring ocean water quality and environmental degradation in multiple locations around the globe. And according to the French startup that built the software and hardware that connects these shellfish into an environmental warning system, they do so with greater sensitivity, better longevity, and lower cost than non-biological systems.
“What we do is called biomonitoring,” Molluscan CEO Ludovic Quinault told me recently on the TechFirst podcast. “We do aquatic—so water quality monitoring—through bivalve mollusks, and mollusks are oysters, for example, or mussels, or clams.”
It’s no easy task. To use biological systems or animals as early warning detectors of pollution, you need to know what is unusual behavior. To sense unusual behavior, you have to deeply know usual behavior. In other words, you have to build essentially a simulation or digital twin of the actual animal and model its normal and healthy behavior, and you have to build a sensor system that detects and transmits abnormal behavior.
Molluscan achieved that thanks to over 20 years of research at the Arcachon Marine Station of the University of Bordeaux. Thanks to that data, the company build what it calls High Frequency Non-Invasive Valvometry: a fancy way of describing its incredibly sensitive technology for monitoring the tiniest of bivalve mollusks movements. When those movements follow irregular or abnormal patterns, the system alerts scientists that something is amiss.
A typical installation includes 16 mollusks, each fitted with a tiny sensor complete with a battery that has years of available power. The sensors, which measure animal behavior 10 times a second, connect to a nearby electronic control box that captures the data from each animal and relays it to scientists or technicians.
16 is the minimum number of mollusks to ensure statistical reliability of the captured signals.
“We use micro-electrodes that are very light, like one gram only outside of water, so it’s like tenths of a gram inside water,” says Quinault. “So the animals don’t feel anything and we measure every movement that they do, meaning the way they open or close at a very high level of precision down to the micrometer.”
A micrometer is one millionth of a meter (a meter is about three feet). A single human hair can be about 50 micrometers in diameter, so the sensors are monitoring motions 50 times smaller than the width of a hair.
The sensors’ precision, however, is rivaled by the oysters, clams, and mussels themselves, which are both more sensitive and much longer-lasting than traditional technology for sampling contaminants in water.
“We tested them in artificial rivers with oil, just to see how they react depending on different level of concentration,” says Quinault. “The sensitivity of the animals in term of reaction and also in term of speed of reaction—and it’s all about concentration—the reality is that they’re very sensitive and we’ve been able to detect with them concentrations that were too low to be seen in the lab.”
In addition, while artificial tech-based instruments tend to foul up in ocean water after just three weeks and require cleaning. That requires an expensive visit by a boat and diver. The mollusks that Molluscan is using, however, live for three years or more, and clean themselves.
This biomonitoring solution is cheap, Quinault says, for situations that require frequent checking. Oil rigs and petrochemical processing locations, for instance, may have requirements to check water quality daily.
A pilot project with TotalEnergies, the big French energy company, found several million dollars in annual cost savings. Where the solution is not cheaper is occasional testing, such as once a quarter.
The real cost savings, however, is early detection of problems before they become massive.
“When you don’t see the pollution, then afterwards, you need to clean,” Quinault says. “What’s the impact, you know, when you need to clean a river or a lake and the impact on the health of the population?”
Seeing problems instantly and reacting quickly, he says, is far cheaper—and better for the environment—than waiting until problems are significant in scale.
Biomonitoring with actual animals is not unique to Molluscan. A Singapore-funded study published in 2017 looked at animal studies for protection from both environmental damage as well as bioterrorism, and concluded that “besides providing early warning to natural hazards, animals can also provide early warning to societal hazards like bioterrorism.”