Phosphorus is essential for life, but its availability often limits productivity in both terrestrial and aquatic ecosystems (Elser et al., 2007). From tropical rain forests to the open oceans, organisms depend on organic phosphorus turnover for their phosphorus nutrition and have evolved complex adaptations that allow them to compete efficiently for this scarce resource (e.g. Lambers et al., 2006; Whitton et al., 2005).