It's easy to see why nudibranchs have captured Johnson's attention for so many years. Despite the common name of "sea slug," nudibranchs are breathtaking in their beauty and variety. Ranging from less than an inch to up to two feet long, nudibranchs occupy a wide range of aquatic habitats, from polar waters to tropical seas, shallow reefs to deep-sea trenches. Over 3,000 species have been discovered and described to date, and scientists estimate that another 3,000 species are yet to be named.
The name nudibranch means "naked gill"unlike their close relatives, the snails, they have no shell covering their body and gills. In some species, these gills take the form of feathery projections on the back; other species have them along the sides of their body; and some don't have gills at all, but instead use their highly branched digestive system for respiration.
Perhaps the most amazing trait of nudibranchs is their ability to exploit food in unique ways. For example, some nudibranchs graze on corals and anemonesrelatives of the jellyfishwithout triggering the stinging cells of their prey. They are then able to sequester these stinging cells into projections on their back. As a result, any predator that comes too close will be stung by these co-opted cells. Other nudibranchs feed on toxic sponges and sequester the toxins in their body without being poisoned themselves.
Johnson's research is helping to further our understanding of thes
|Contact: Stephanie Stone|
California Academy of Sciences