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Published on: October 1, 2011
Scaling metabolism from organisms to ecosystems
Brian J Enquist1, Evan P Economo, Travis E Huxman
1Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA. benquist@u.arizona.edu
Nature
|June 6, 2003
Summary
This study presents a new model for ecosystem respiration, showing CO2 and energy fluxes are independent of biomass but influenced by temperature and resources. This helps understand biosphere-atmosphere interactions in a changing climate.
Area of Science:
- Ecology
- Global Change Biology
- Biogeochemistry
Background:
- Understanding ecosystem energy and material fluxes is crucial for global change biology and ecology.
- Ecosystem respiration is a key component of the carbon cycle and influences biosphere responses to climate change.
Purpose of the Study:
- To develop a general model for ecosystem respiration based on metabolic kinetics and organismal resource use.
- To investigate the factors influencing CO2 and energy fluxes between the atmosphere and biosphere.
Main Methods:
- Derived a general model for ecosystem respiration using metabolic reaction kinetics and resource scaling.
- Utilized a network of CO2 flux towers to collect data on ecosystem respiration variation within sites.
- Analyzed annual flux data between sites to assess dependence on temperature and latitude.
Main Results:
- The model predicts CO2 and energy fluxes are invariant to ecosystem biomass.
- Fluxes are strongly influenced by temperature, cellular metabolism variations, and limiting resource supply (water/nutrients).
- Within-site respiration variation supports model predictions, but between-site annual flux shows weak dependence on average temperature or latitude, presenting a paradox.
Conclusions:
- The developed model provides a quantitative framework for understanding atmosphere-biosphere energy and material exchange.
- Despite a paradox in between-site temperature dependence, the model offers insights into ecosystem respiration regulation.
- Further research is needed to resolve the observed temperature-latitude paradox in annual ecosystem respiration fluxes.
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