Cybermussels taste the river (Image: University of Iowa)

RIVER mussels wearing tiny sensor backpacks could help monitor the Mississippi for dangerous pollutants. The plan is for the mussels to measure the flow of nitrogen-rich fertiliser that courses down the river and empties into the Gulf of Mexico. An excess of the nutrient there can cause dead zones that suffocate marine life.

Mussels will measure the flow of nitrogen-rich fertiliser that courses down the Mississippi

Researchers at the University of Iowa in Iowa City have attached wireless sensor packages to mussels for measuring their “gape” – how much their shells are open. They are also working on monitoring the animals’ heart rate, how much water they filter and when they burrow. Each behaviour changes according to the water conditions.


In a previous experiment the mussels’ backpacks successfully transmitted signals to a receiver on the riverbed that relayed the signals to a lab on shore via a wired connection. The researchers are now testing their system on a group of mussels living in a tank, so that they can measure how the mussel shells gape in response to varying nitrogen levels.

The advantage of using mussels as a sensing mechanism is that they stay clean, unlike the electronic sensors that are normally used to monitor nitrogen content, says team member Anton Kruger.

“Everything flocks to it and all kinds of muck starts to grow on the device,” he says. “But if you put a mussel out, they clean themselves and live for years and years.” Kruger will present the design for the mussel backpacks next month at the Sensor Applications Symposium in Galveston, Texas.

Team member Craig Just says the creatures could also be useful as hazardous waste or spill indicators. “They’d be the canary in the coal mine,” he says. They could also help researchers understand how mussels feed on nitrogen from rivers.

Donna Myers of the US Geological Survey in Reston, Virginia, praised the idea’s creativity, adding that you still need conventional sensors for precise readings of nitrogen concentrations in the river. At the moment the USGS has about two dozen in operation. “But you can’t afford to put sensors everywhere,” Myers says. “It would be wonderful if they came up with something that could be used as an alternative.”