A Milestone for Sea Slugs

USF study on a slug that turns sunlight into energy lands in Britannica’s “Book of the Year.



USF News Report


TAMPA, Fla. (April 27, 2011) – A graceful, green sea slug which turns sunlight into energy brought USF biology professor Sidney (Skip) Pierce worldwide attention last year and now brought the professor full circle when Encyclopedia Britannica recently named Pierce’s research among seven significant discoveries in 2010 in the life sciences section of its iconic Book of the Year for 2011.


For Pierce, the sea slug research making it into the prestigious volume was a reminder of the path that brought him to become one of the world’s noted biologists: as an 18-year-old trying to figure out what he wanted to do with his life he took a job selling Encyclopedia Britannica door-to-door. Two weeks and too few sales later, Pierce decided to stay in college.

Now, Pierce’s work will be in every library in the world.

The sea slug - Elysia chlorotica, which lives in waters on the east coast of the U.S. and Canada - has been described as part animal and part plant because it produces its own chlorophyll and can carry out photosynthesis, turning sunlight into energy. Pierce worked with postdoctoral researcher Nicholas Curtis and Ph.D. candidate Julie Schwartz and used radioactive tracing techniques to determine the vibrant green creatures are able to manufacture chlorophyll themselves, the first animal ever discovered to be able to this.

Pierce’s study demonstrated that a symbiotic relationship between these animals and chloroplasts from their algal food have resulted in the movement of functional genes, called gene transfer, between the two species. The transferred genes are transmitted to the next generation, so they have become part of the slug’s DNA.

When the discovery was announced last year at a scientific conference in Seattle and then published in the journal Symbiosis, it caused a worldwide sensation. The story went viral on websites around the world and Pierce was interviewed for broadcast and print stories in Italy, Germany, Brazil, Russia and Japan. An NPR program host in Minnesota even wrote and broadcast a song about the slug.

But for Pierce, the modern media sensation still takes a backseat to making the pages of the Encyclopedia Britannica.

“Anyone can get anything on the Internet.  I think the significance of being recognized as making a discovery of importance in the 2011 Book of the Year is sort of the worldwide public archivalness of the Encyclopedia Britannica and, to me, its old-school flavor,” he said. 

“Being included in it is a nice honor, a record of which seems likely to persist and - more important - it is in a place where kids doing science reports are likely to come across our work.  It is a nice compliment to us.”