kelp hugger 

A marine environmentalist or one who believes underwater kelp forests and all living things in the ocean or beaches should not be damaged or harmed. Someone who works to protect the aquatic environment from destruction or pollution. The synonym of a tree hugger or hippie except in an oceanic or aquatic environment.

Dana's such a kelp hugger that she joined Surfrider Foundation and now does the beach clean-up every month.

kelp hugger by LDL1 February 6, 2010