  Organisms are composed of multiple chemical elements such as carbon,
nitrogen, and phosphorus. The scarcity of any of these elements can severely
restrict organismal and population growth. However, many trophic interaction
models only consider carbon limitation via energy flow. In this paper, we
construct an algal growth model with the explicit incorporation of light and
nutrient availability to characterize both carbon and phosphorus limitations.
We provide a global analysis of this model to illustrate how light and nutrient
availability regulate algal dynamics.
