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Variable Stoichiometry and Homeostatic Regulation of Bacterial Biomass Elemental Composition

By J. Thad Scott, James B. Cotner and Timothy M. LaPara

Abstract

Prokaryotic heterotrophs (hereafter, bacteria) represent a large proportion of global biomass, and therefore bacterial biomass stoichiometry likely exerts control on global phosphorus (P), carbon (C), and nitrogen cycling and primary productivity. In this study we grew recently isolated freshwater heterotrophic bacteria across an ecologically relevant range of resource C:P ratios (organic C to P ratio in available resources) to quantify the P requirements of these organisms and examine the degree to which they regulated their P content under P-sufficient and P-deficient conditions. Bacterial biomass was only limited by P when resource C:P was greater than 250 (by atoms). Bacterial C:P ranged from 71 to 174 under P sufficiency and from 252 to 548 under P deficiency. Bacteria exhibited very little C:P homeostasis under P-sufficient growth conditions, greater C:P homeostasis under P-deficient conditions, and the ability of bacteria to outcompete one another in short-term experiments depended on a tradeoff between storing excess P for later use under P-deficient conditions or immediately using P to produce more biomass. These results indicate that freshwater heterotrophic bacteria are not as P-rich as previously thought and that homeostatic regulation of C:P stoichiometry depends on the individual taxa and what resource (organic C or available P) is limiting bacterial growth. Individual bacterial populations can vary between strong C:P homeostasis under P deficiency to virtually no C:P homeostasis under P sufficiency, but variation between taxa and the effect this has on competitive ability may dampen the signal in C:PB at the bacterial community level. Nevertheless, the prevalence of homeostatic and non-homeostatic strategies in a bacterial community should have important implications for nutrient regeneration and carbon cycling

Topics: Microbiology
Publisher: Frontiers Research Foundation
OAI identifier: oai:pubmedcentral.nih.gov:3283892
Provided by: PubMed Central

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Citations

  1. 95, 6578–6583. Conflict of Interest Statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
  2. (2005). An intracellular phosphate buffer filters transient fluctuations in extracellular phosphate levels.
  3. and Smith,J.E.(2007).Globalanalysisof nitrogen and phosphorus limitation of primary producers in freshwater, marine, and terrestrial ecosystems.
  4. (2003). Are bacteria more like plants or animals? Growth rate and resource dependence of bacterial C:N:P stoichiometry.
  5. (2007). Changes in morphology and elemental composition of Vibrio splendidus along a gradient from carbon-limited to phosphatelimited growth.
  6. (2008). Counterintuitive carbonto-nutrient coupling in an Arctic pelagic ecosystem.
  7. (2007). Cultivation of bacteria and fungi,” in Manual of Environmental Microbiology, eds
  8. (2008). Direct measurement of the δ13Csignatureofcarbonrespiredby bacteria in lakes: linkages to potential carbon sources, ecosystem baseline metabolism, and CO2 fluxes.
  9. Does Leibeg’s law of the minimum scale up from species to communities?
  10. (2001). Dominance of bacterial metabolism in oligotrophic relative to eutrophic waters.
  11. (2002). Ecological Stoichiometry: The Biology of Elements from Molecules to the Biosphere.
  12. (2002). Elemental C, N, and P cell content of individual bacteria collected at the BermudaAtlantic Time-series Study (BATS) site.
  13. (2008). Elemental content of Pseudomonas fluorescens varies with growth rate and temperature: a replicated chemostat experiment addressing ecological stoichiometry.
  14. (2004). Elemental stoichiometry of a heterotrophic bacterial community in a freshwater lake: implications for growth- and resource-dependent variations.
  15. (2010). Freshwater bacteria are stoichiometrically flexible www.frontiersin.org
  16. (2000). Heterotrophic, planktonic bacteria and cycling of phosphorus: phosphorus requirements, competitive ability and food web interactions.
  17. (1999). How stable is stable? Function versus community composition.
  18. (2006). Influence of microbial activity on plantmicrobial competition for organic and inorganic nitrogen.
  19. (2004). Nitrogen uptake by arctic soil microbes and plants in relation to soil nitrogen supply.
  20. (1995). Nutritional enrichment of a microbial community: the effects on activity, elemental composition, community structure, and virus production.
  21. (2004). Optimal nitrogento-phosphorus stoichiometry of phytoplankton.
  22. (2009). Phytoplankton in the ocean use non-phosphorus lipids in response to phosphorus scarcity.
  23. (2000). Polyphosphate and the phosphate pump. A n n u .R e v .M i c r o b i o l .54,
  24. (1996). Ratios of carbon, nitrogen, and phosphorus in Pseudomonas fluorescens as a model for element ratios and nutrient regeneration.
  25. (2008). The influence of dissolved organic carbon on bacterial phosphorus uptake and bacterial-phytoplankton dynamics in two Minnesota lakes.
  26. (2008). The unseen majority: soil microbes as drivers of plant diversity and productivity in terrestrial ecosystems.
  27. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits noncommercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
  28. (1992). Uptake of dissolved inorganic and organic phosphorus compounds by phytoplankton and bacterioplankton.
  29. (2005). Use of non-limiting substrates to increase size; a generic strategy to simultaneously optimize uptake and minimize predation in pelagic osmotrophs.
  30. (2012). Variable stoichiometry and homeostatic regulation of bacterial biomass elemental composition.

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