Nutritional indicators and ecological stoichiometry
Ecological stoichiometry (ES) examines the causes and consequences of elemental imbalances in the environment. A central theme in ES is that differences between the elemental requirements of organisms and their resources create stress that alters physiological, ecological, and evolutionary dynamics. The nutritional history of an organism, however, can be difficult to determine particularly for field-caught animals. These difficulties arise, at least in consumers, because nutritional components in food tend to covary and due to the reliance of bioassay type nutritional assays. Inferring the nutritional past of animals could use emerging tools that characterize the molecular and biochemical properties (e.g., transcriptomic, proteomic, metabolomic properties) of animals that are sensitive to dietary limitation. Here we examine the potential to develop and apply nutritional profiling to stoichiometric research. In general, this approach will identify and measure a suite of molecular responses in animals known to reliably indicate a particular type of nutritional stress. Nutritional profiling would be useful to verify the type and intensity of nutritional limitation in animals consuming unknown diets and thereby provide a better understanding of diverse ecological topics. Nutritional profiles could be beneficial in determining whether and how co-limitation by multiple nutrients affects consumer life-history traits and ecological interactions. This approach could also be applied to study stoichiometric knife edges by delineating better when limitation switches from one element to another. Nutritional indicators applied to population and community-level experiments could show how the nutritional status of different taxa varies as their populations and food resources vary through time. This type of information could be particularly useful in examining inter-specific competition of taxa that presumably have different nutritional requirements.
Altogether, application of this approach has the potential to transform the study of nutrients in ecology from organismal to ecosystem level scales.