Stream ecologist Margaret Palmer once kept a low profile, refusing even to return calls from reporters interested in her work. But over the past decade, the University of Maryland academic has emerged to become a prominent player in injecting science into complex environmental controversies. She's led influential studies raising questions about the effectiveness of the booming river restoration business and documenting the damage done by "mountaintop removal" coal mines in Appalachia. She's helped shape national policy and appeared in contentious court battles as an expert witness. She even made a memorable appearance on The Colbert Report, a popular television show. Now, she's leading a new $27 million research center aimed at bringing scientists into policy discussions. But at times her passion for doing relevant science can bring substantial discomfort.