Title

The effects of 11 yr of CO2 enrichment on roots in a Florida scrub-oak ecosystem

Authors

Authors

F. P. Day; R. E. Schroeder; D. B. Stover; A. L. P. Brown; J. R. Butnor; J. Dilustro; B. A. Hungate; P. Dijkstra; B. D. Duval; T. J. Seiler; B. G. Drake;C. R. Hinkle

Comments

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Abbreviated Journal Title

New Phytol.

Keywords

CO2 enrichment; disturbance; ground-penetrating radar; minirhizotrons; root biomass; root closure; scrub-oak; ELEVATED ATMOSPHERIC CO2; GROUND-PENETRATING RADAR; LONG-TERM EXPOSURE; SOIL CARBON; FINE ROOTS; NITROGEN LIMITATION; ABOVEGROUND BIOMASS; NATURAL ECOSYSTEMS; TALLGRASS PRAIRIE; TEMPERATE FOREST; Plant Sciences

Abstract

Uncertainty surrounds belowground plant responses to rising atmospheric CO2 because roots are difficult to measure, requiring frequent monitoring as a result of fine root dynamics and long-term monitoring as a result of sensitivity to resource availability. We report belowground plant responses of a scrub-oak ecosystem in Florida exposed to 11yr of elevated atmospheric CO2 using open-top chambers. We measured fine root production, turnover and biomass using minirhizotrons, coarse root biomass using ground-penetrating radar and total root biomass using soil cores. Total root biomass was greater in elevated than in ambient plots, and the absolute difference was larger than the difference aboveground. Fine root biomass fluctuated by more than a factor of two, with no unidirectional temporal trend, whereas leaf biomass accumulated monotonically. Strong increases in fine root biomass with elevated CO2 occurred after fire and hurricane disturbance. Leaf biomass also exhibited stronger responses following hurricanes. Responses after fire and hurricanes suggest that disturbance promotes the growth responses of plants to elevated CO2. Increased resource availability associated with disturbance (nutrients, water, space) may facilitate greater responses of roots to elevated CO2. The disappearance of responses in fine roots suggests limits on the capacity of root systems to respond to CO2 enrichment.

Journal Title

New Phytologist

Volume

200

Issue/Number

3

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

778

Last Page

787

WOS Identifier

WOS:000325555400020

ISSN

1469-8137

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