Ecological Stoichiometry

by

Mehdi Cherif, James Elser

• LAST REVIEWED: 19 November 2021
• LAST MODIFIED: 31 March 2016
• DOI: 10.1093/obo/9780199830060-0146

Introduction

Ecological stoichiometry (ES) is the study of the balance of energy and multiple chemical elements in ecological interactions. Although much of the foundation of this field lies in studies of lakes (and especially of lake plankton), the application of ES has greatly expanded in 21st century, with extensions to streams, soils, grasslands, forests, and other ecosystems. This article provides a guide to recent introductory articles and reviews of the ES approach, to some of the foundational papers that preceded the formal definition of ES, and to a cross-section of papers dealing with biochemical, evolutionary, and ecological (especially biogeochemical) applications of ES. The field remains highly dynamic: a topic search on “ecolog stoichiometry” in ISI Web of Science yields more than 6,100 citations per year (in 2013; compared to less than five hundred in 1993). Thus, this annotated bibliography can only touch on the tip of this growing iceberg.

Introductory Works and Syntheses

The common framework provided by the study of multiple chemical elements pointed the way toward integration of diverse fields within ecology (physiological ecology, community ecology, biogeochemistry) and of ecology with other realms of biology, such as evolutionary biology. The possibility of direct elemental (P) limitation of consumer growth due to its “dilution” in the C-rich biomass that is generated when photoautotrophs (algae, plants) are nutrient-limited was inferred by workers studying freshwater zooplankton and reported in early papers such as Urabe and Watanabe 1992 and Sterner and Hessen 1994. The impacts of such stoichiometric imbalance on nutrient recycling were analyzed mathematically and compared to existing data (Sterner 1990). Soon thereafter, researchers began to hypothesize about the biochemical and evolutionary drivers that are responsible for the C:N:P ratios that characterize biomass of both consumers and producers, suggesting an important role of growth rate–related allocation to P-rich ribosomal RNA in the “growth rate hypothesis” that is developed in Elser, et al. 1996. Sterner and Elser 2002 is a foundational work that brought together a large number of disparate research threads in ecology and stimulated considerable new research, including an expansion of stoichiometric thinking into new realms (“biological stoichiometry”), such as biochemical allocation, life history evolution, and even cancer dynamics.

• Elser, J. J., D. R. Dobberfuhl, N. A. MacKay, and J. H. Schampel. 1996. Organism size, life history, and N:P stoichiometry: Toward a unified view of cellular and ecosystem processes. BioScience 46:674–684.

  DOI: 10.2307/1312897

  This synthetic paper extends stoichiometric thinking downwards toward cellular and biochemical levels and sketches several hypotheses about observed variation in C:N:P ratios in biota, including the “Growth Rate Hypothesis” (GRH) connecting C:N:P ratios to growth rate and RNA allocation.

• Sterner, R. W. 1990. The ratio of nitrogen to phosphorus resupplied by herbivores: Zooplankton and the algal competitive arena. American Naturalist 136:209–229.

  DOI: 10.1086/285092

  Mathematical modeling of the mass balances of N and P into a strictly homeostatic consumer was used to predict a non-linear relationship between the N:P of recycled nutrients and the N:P of ingested food as well as dependence on body N:P of the consumer.

• Sterner, R. W., and D. O. Hessen. 1994. Algal nutrient limitation and the nutrition of aquatic herbivores. Annual Review of Ecology, Evolution and Systematics 25:1–29.

  DOI: 10.1146/annurev.es.25.110194.000245

  An early synthesis of extant and emerging data highlighting the potential importance of stoichiometric imbalance between autotrophs and herbivores, integrating physiological to ecosystem level dimensions.

• Sterner, R. W., and J. J. Elser. 2002. Ecological stoichiometry: The biology of elements from molecules to the biosphere. Princeton, NJ: Princeton Univ. Press.

  This is considered the definitive textbook of the field. Written for graduate students and advanced undergraduates, the book develops and builds stoichiometric reasoning from cellular and biochemical levels through organismal physiology to trophic ecology and ecosystem nutrient cycling.

• Urabe, J., and Y. Watanabe. 1992. Possibility of N or P limitation for planktonic cladocerans: An experimental test. Limnology and Oceanography 37:244–251.

  DOI: 10.4319/lo.1992.37.2.0244

  This important paper introduces the concept of “Threshold Elemental Ratio” (TER) that delineates the breakpoint between C-limited and nutrient-limited growth for a consumer and provides estimates of TER for C:N and C:P for two species of freshwater zooplankton.