Roots and fungi accelerate carbon and nitrogen cycling in forests exposed to elevated CO2.

Autor:	Phillips, Richard P., Meier, Ina C., Bernhardt, Emily S., Grandy, A. Stuart, Wickings, Kyle, Finzi, Adrien C., Knops, Johannes
Předmět:	EXUDATION (Botany) RHIZOSPHERE PLANT-microbe relationships NITROGEN cycle CARBON cycle FORESTS & forestry CARBON dioxide
Zdroj:	Ecology Letters; Sep2012, Vol. 15 Issue 9, p1042-1049, 8p
Abstrakt:	A common finding in multiple CO2 enrichment experiments in forests is the lack of soil carbon ( C) accumulation owing to microbial priming of 'old' soil organic matter ( SOM). However, soil C losses may also result from the accelerated turnover of 'young' microbial tissues that are rich in nitrogen ( N) relative to bulk SOM. We measured root-induced changes in soil C dynamics in a pine forest exposed to elevated CO2 and N enrichment by combining stable isotope analyses, molecular characterisations of SOM and microbial assays. We find strong evidence that the accelerated turnover of root-derived C under elevated CO2 is sufficient in magnitude to offset increased belowground inputs. In addition, the C losses were associated with accelerated N cycling, suggesting that trees exposed to elevated CO2 not only enhance N availability by stimulating microbial decomposition of SOM via priming but also increase the rate at which N cycles through microbial pools. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
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