Most algae and animals that live on the seafloor can be sampled only by SCUBA divers or dredging up samples from the deep. This kind of data requires a ton of effort to collect and means scientists are limited in their knowledge of changes in their abundances through time. Giant Kelp (Macrocystis pyrifera) can grow up to a foot a day and forms lush canopies that can be seen by some of the earliest satellites put into space.
 
The canopy of floating kelp forests will show up in pictures as clusters of green pixels fringing the coastline. Zooniverse’s Floating Forests asks citizen scientists to outline these forest canopies. As citizen scientists go through these pictures, they will begin to see how coastlines of different areas around the world have changed over time.
 
The images used in the Floating Forests project are from Landsat images taken every 16 days from 1984 to the present. However, Landsat was not designed to be able to see kelp—the sea plant’s reflectance signature is just at the edge of its detection abilities. Because of this, kelp and something as simple as the glint of sun off of a wave look the same to a computer. But to a person, the shapes and patterns of kelp forests are fairly obvious.
 
Kelp can serve as the foundation for an entire ecosystem, providing food for all manner of herbivores from tiny shrimp to ravenous sea urchins to grazing fish. Loss of kelp forests can have dire consequences for the health, resilience and productivity of coastal ecosystems.
 
By providing classifications of changes in kelp canopy cover over the past 30 years on global scales, this project will identify regions where kelp forests have experience significant long-term changes. Scientists will then identify the likely environmental and human drivers of these observed changes.