Spiral coil

Salps are planktonic filter-feeders — each one a tireless vacuum continuously clearing phytoplankton cells from the sea by filtering water through a mucus net as it swims. These marine animals can be found singly or in chains, such as this colony of gold-colored Pegea Socia, common off the central and northern California coast. Scientists found that salps may play an important and overlooked role in determining the fate of the greenhouse gas carbon dioxide in the ocean.

(Photo by Larry Madin, Woods Hole Oceanographic Institution)