Hidden below the surface of the sea, a flock of underwater sensors collects data along California’s coastline. Their mission? Capture the quiet signals of climate change in our iconic kelp forests.

The songbirds of our Coastal Canary Project are Reef Check’s small but tough temperature loggers. The loggers monitor temperature fluctuations every ten minutes.

The sensors are spread out across the coast of California from San Diego to Humboldt county. The matchbox-sized loggers alone monitor temperatures at over 75 survey sites, each one fixed with a stainless steel bolt into the rocky reef about 12 m (40 ft) deep. The sensors tough out 12-month deployments before they’re retrieved and swapped out with fresh units to continue the mission.

Like canaries in a coal mine, these sensors detect delicate shifts in our kelp forests before more drastic impacts surface. As climate change alters the oceans, this data allows us to monitor and mitigate its effects and paints a fuller picture of our changing kelp forest ecosystem.