Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm

Nottingham, A.T.; Turner, B.L.; Whitaker, J. ORCID: https://orcid.org/0000-0001-8824-471X; Ostle, N.J.; McNamara, N.P. ORCID: https://orcid.org/0000-0002-5143-5819; Bardgett, R.D.; Salinas, N.; Meir, P.. 2015 Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm. Biogeosciences, 12 (20). 6071-6083. https://doi.org/10.5194/bg-12-6071-2015

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Abstract/Summary

Aboveground primary productivity is widely considered to be limited by phosphorus (P) availability in lowland tropical forests and by nitrogen (N) availability in montane tropical forests. However, the extent to which this paradigm applies to belowground processes remains unresolved. We measured indices of soil microbial nutrient status in lowland, sub-montane and montane tropical forests along a natural gradient spanning 3400 m in elevation in the Peruvian Andes. With increasing elevation there were marked increases in soil concentrations of total N, total P, and readily exchangeable P, but a decrease in N mineralization determined by in situ resin bags. Microbial carbon (C) and N increased with increasing elevation, but microbial C : N : P ratios were relatively constant, suggesting homeostasis. The activity of hydrolytic enzymes, which are rich in N, decreased with increasing elevation, while the ratio of enzymes involved in the acquisition of N and P increased with increasing elevation, further indicating an increase in the relative demand for N compared to P with increasing elevation. We conclude that soil microorganisms shift investment in nutrient acquisition from P to N between lowland and montane tropical forests, suggesting that different nutrients regulate soil microbial metabolism and the soil carbon balance in these ecosystems.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.5194/bg-12-6071-2015
UKCEH and CEH Sections/Science Areas:	Shore
ISSN:	1726-4170
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
NORA Subject Terms:	Ecology and Environment Agriculture and Soil Science
Related URLs:	Discussion paper
Date made live:	09 Nov 2015 14:01 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/512146

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