Research technician Kristen Mello, left, and graduate student Brandon O'Brien examine seaweed samples at a laboratory on Appledore Island. The Gulf of Maine is the latest global hotspot to lose kelp.

Research technician Kristen Mello examines a red scrub-like seaweed sample under a microscope, shown on the microscope's display screen, at a laboratory on Appledore Island.

Mello shows a sample of a red shrub-like seaweed collected in the waters off Appledore Island. Kelp forests are critical to the fishing industry but are disappearing around the world.

A string of ducks paddle past a warning flag over research divers, out to collecting samples of a red shrub-like seaweed.

A sample of a red shrub-like seaweed, bagged in sea water, collected in the waters off Appledore Island.

Research divers swim out to collect samples of a red shrub-like seaweed in the waters off Appledore Island.

Research technician Kristen Mello passes a sample of a red shrub-like seaweed collected in the waters off Appledore Island.

Research technician Kristen Mello, right, dons her wetsuit with graduate student Brandon O'Brien as they prepare to dive for seaweed samples.

O'Brien examines a red scrub-like seaweed sample at a laboratory on Appledore Island. Scientists say the likely culprits in the disappearance of kelp are climate change and invasive species. In Maine, the invaders are other seaweeds.

Researchers prepare to dive for seaweed samples as a ferry back to New Castle, N.H. departs from Appledore Island.