Chip Small, a PhD student at the Odum School of Ecology, is featured in the “Article Spotlight” in the December 2009 issue of the Journal of the North American Benthological Society. The article by Small, OSE doctoral student Ashley Helton, and Caner Kazanci, Assistant Professor in the UGA Department of Mathematics and Faculty of Engineering, is entitled “Can consumer stoichiometric regulation control nutrient spiraling in streams?” The article explores how consumers affect the downstream movement of different elements in stream ecosystems.

Most animals are homeostatic – that is, they regulate their own elemental composition by retaining the nutrients they need (their limiting nutrients) for longer periods of time, and excreting non-essential nutrients more quickly. Assuming that most consumers in a stream have the same limiting nutrients, Small and his colleagues posited that limiting and non-limiting nutrients will travel downstream at very different rates once they enter a stream inhabited by these homeostatic consumers.

They developed a model that incorporates stoichiometry – the ratio of carbon to nitrogen to phosphorus in an organism – with time and distance to determine how the presence of homeostatic consumers affects the progress of limiting and non-limiting nutrients. Their results suggest that when consumers are present in large numbers – for instance, as with invasive species – stream nutrient dynamics can be greatly affected.

The article is part of the Rosemary Mackay Fund Series in JNABS. According to JNABS, “This series is designed to give authors the opportunity to present ideas that are new and different (new analytical or philosophical approaches, new paradigms and concepts, novel applications of old or new methods or of ideas and tools from other disciplines to benthology).”