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Biotic and abiotic controls on biogenic volatile organic compound fluxes from a subalpine forest floor
Author(s) -
Gray Christopher M.,
Monson Russell K.,
Fierer Noah
Publication year - 2014
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2013jg002575
Subject(s) - abiotic component , montane ecology , environmental science , subalpine forest , forest floor , ecology , biotic component , environmental chemistry , soil science , chemistry , biology , soil water
Nonmethane biogenic volatile organic compounds (BVOCs) play key roles in the atmosphere, where they can influence a wide range of chemical processes, and in soils, where they can alter the rates of biogeochemical cycles and impact the growth of plants and soil organisms. However, the diversity and quantities of BVOCs released from or taken up by soils remain poorly characterized as do the biotic and abiotic controls on these fluxes. Here we used proton transfer reaction mass spectrometry to quantify BVOC flux rates from soils with and without active root systems in a subalpine coniferous forest. The total measured BVOC flux averaged 102 nmol m −2 h −1 (an estimated 2.0 µg‐C m −2 h −1 ). The individual BVOCs with the highest net emissions from soil included monoterpenes and methanol (averaging 646 and 641 ng‐C m −2 h −1 , respectively) while soil represented a net sink of isoprene (−98 ng‐C m −2 h −1 ) and formaldehyde (−37 ng‐C m −2 h −1 ). Tree roots, directly or indirectly, contributed an average of 53% of the total carbon emitted from the soil as BVOCs, with methanol and acetaldehyde among those BVOCs most strongly associated with active root presence. The fluxes of most of the dominant BVOCs emitted from soil, including methanol, increased linearly with increasing temperature. Together the fluxes of certain BVOCs into or out of the forest floor (particularly methanol, isoprene, and monoterpenes) are likely relevant to ecosystem‐level processes and belowground ecology, but these fluxes are highly variable and are strongly controlled by both root presence and soil abiotic conditions.