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About the Authors:
Elise Pendall
* E-mail: [email protected]
Affiliation: Department of Botany and Program in Ecology, University of Wyoming, Laramie, Wyoming, United States of America
Jana L. Heisler-White
Affiliations United States Department of Agriculture – Agricultural Research Service, Rangeland Resources Research Unit and Northern Plains Area, Fort Collins, Colorado, United States of America, Departments of Botany; Ecosystem Science and Management, and Program in Ecology, University of Wyoming, Laramie, Wyoming, United States of America
David G. Williams
Affiliation: Departments of Botany; Ecosystem Science and Management, and Program in Ecology, University of Wyoming, Laramie, Wyoming, United States of America
Feike A. Dijkstra
Affiliations United States Department of Agriculture – Agricultural Research Service, Rangeland Resources Research Unit and Northern Plains Area, Fort Collins, Colorado, United States of America, Faculty of Agriculture and Environment, University of Sydney, Sydney, New South Wales, Australia
Yolima Carrillo
Affiliations Department of Botany and Program in Ecology, University of Wyoming, Laramie, Wyoming, United States of America, Faculty of Agriculture and Environment, University of Sydney, Sydney, New South Wales, Australia
Jack A. Morgan
Affiliation: United States Department of Agriculture – Agricultural Research Service, Rangeland Resources Research Unit and Northern Plains Area, Fort Collins, Colorado, United States of America
Daniel R. LeCain
Affiliation: United States Department of Agriculture – Agricultural Research Service, Rangeland Resources Research Unit and Northern Plains Area, Fort Collins, Colorado, United States of America
Introduction
Models predict declining C sequestration in the coming century [1], [2], [3] as ecosystem respiration (Reco) is preferentially stimulated over ecosystem photosynthesis (Peco), but experimental tests for these predictions are lacking [4]. Experimental manipulations of single global change factors have greatly improved our understanding of ecological processes that regulate C exchange [5], [6]. Photosynthesis is stimulated by elevated [CO2] due to increased biochemical forcing and improved water use efficiency [7], but the magnitude of these mechanisms varies both within and across ecosystems [8]. Warming has been shown to increase, decrease, and have no effect on C assimilation [6] – responses that are tied to enzymatic reaction rates, plant photosynthetic acclimation, potential changes in growing season length, and resource availability. On a physiological level, Reco, composed of both autotrophic (Ra) and heterotrophic (Rh) respiration, responds more strongly to temperature than does photosynthesis [9], underpinning model predictions that ecosystem C...