Brian Helmuth

Researchers use ‘robomussels’ to monitor climate change

Tiny robots have been helping researchers study how cli­mate change affects bio­di­ver­sity. Devel­oped by North­eastern Uni­ver­sity sci­en­tist Brian Hel­muth, the “robo­mus­sels” have the shape, size, and color of actual mus­sels, with minia­ture built-​​in sen­sors that track tem­per­a­tures inside the mussel beds.

For the past 18 years, every 10 to 15 min­utes, Hel­muth, pro­fessor in the Col­lege of Sci­ence and the School of Public Policy and Urban Affairs, and a global research team of 48 sci­en­tists have used robo­mus­sels to track internal body tem­per­a­ture, which is deter­mined by the tem­per­a­ture of the sur­rounding air or water, and the amount of solar radi­a­tion the devices absorb. They place the robots inside mussel beds in oceans around the globe and record tem­per­a­tures. The researchers have built a data­base of nearly two decades worth of data enabling sci­en­tists to pin­point areas of unusual warming, inter­vene to help curb damage to vital marine ecosys­tems, and develop strate­gies that could pre­vent extinc­tion of cer­tain species.

Housed at Northeastern’s Marine Sci­ence Center in Nahant, Mass­a­chu­setts, this largest-​​ever data­base is not only a remark­able way to track the effects of cli­mate change, the find­ings can also reveal emerging hotspots so pol­i­cy­makers and sci­en­tists can step in and relieve stres­sors such as ero­sion and water acid­i­fi­ca­tion before it’s too late.

“They look exactly like mus­sels but they have little green blinking lights in them,” says Hel­muth. “You basi­cally pluck out a mussel and then glue the device to the rock right inside the mussel bed. They enable us to link our field obser­va­tions with the phys­i­o­log­ical impact of global cli­mate change on these eco­log­i­cally and eco­nom­i­cally impor­tant animals.”

The research appeared in a new paper pub­lished Tuesday in the journal Sci­en­tific Data.

A barom­eter of cli­mate change

For eco­log­ical fore­casters such as Hel­muth, mus­sels act as a barom­eter of cli­mate change. That’s because they rely on external sources of heat such as air tem­per­a­ture and sun expo­sure for their body heat and thrive, or not, depending on those con­di­tions. Using field­work along with math­e­mat­ical and com­pu­ta­tional models, Hel­muth fore­casts the pat­terns of growth, repro­duc­tion, and sur­vival of mus­sels in inter­tidal zones.

Over the years, he and his col­leagues have found sur­prises: “Our expec­ta­tions of where to look for the effects of cli­mate change in nature are more com­plex than antic­i­pated,” says Hel­muth. For example, in an ear­lier paper in the journal Sci­ence, his team found that hotspots existed not only at the southern end of the species’ dis­tri­b­u­tion, in this case, southern Cal­i­fornia; they also existed at sites up north, in Oregon and Wash­ington state.

“These datasets tell us when and where to look for the effects of cli­mate change,” he says. “Without them we could miss early warning signs of trouble.”

The robo­mus­sels’ near-​​continuous mea­sure­ments serve as an early warning system. “If we start to see sites where the ani­mals are reg­u­larly get­ting to tem­per­a­tures that are right below what kills them, we know that any slight increase is likely to send them over the edge, and we can act,” says Helmuth.

It’s not only the mus­sels that may be pulled back from the brink. The advance notice could inform every­thing from main­taining the bio­di­ver­sity of coastal sys­tems to deter­mining the best—and worst—places to locate mussel farms.

“Losing mussel beds is essen­tially like clearing a forest,” says Hel­muth. “If they go, every­thing that’s living in them will go. They are a major food supply for many species, including lob­sters and crabs. They also func­tion as fil­ters along near-​​shore waters, clearing huge amounts of par­tic­u­lates. So losing them can affect every­thing from the growth of species we care about because we want to eat them to water clarity to bio­di­ver­sity of all the tiny ani­mals that live on the insides of the beds.”

Originally published in news@Northeastern on October 12, 2016.

College of Science