Background/Question/Methods Making decisions in the face of uncertainty is a way of life—for scientists, as well as for non-scientists, but we, as a society, appear to wish for more certainty from the scientific enterprise, especially ecological science.  There are at least three dilemmas for ecologists in this regard:  (1) scientists remain ill equipped to discuss certainty as well as uncertainty in ways that are either understandable, compelling, or useful to non-scientists, (2) understanding what certainty is necessary for decision making by different sectors (policy, management, stewardship, and (3) realizing when, where, and how science can effectively be used, or when scientists should weigh in, for management and policy decisions. 
We begin with an overview of the “scientist’s dilemma”, or situations in which scientists are asked to interpret data beyond their statistical certainty.  We next use case studies to illustrate the dilemmas, challenges, as well as opportunities for ecosystem scientists.  We first focus on the challenge of estimating atmospheric deposition—the loading of pollutants, and nutrients, from atmosphere to landscapes—when these measurements are necessary for air pollution policy as well as effects research.  The second focuses on the role, or not, of ecological uncertainty in setting management targets for in-lake nutrient controls that are based on land use practices.
Results/Conclusions

We use these two case studies both to point to successful and unsuccessful strategies for addressing ecologists’ dilemmas, and to make suggestions about mechanisms and processes that might enhance scientific translation, and understanding, among scientists, managers, policy makers and stewards.