Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone
- 18 February 2006
- journal article
- Published by Springer Science and Business Media LLC in Oecologia
- Vol. 148 (3), 503-516
- https://doi.org/10.1007/s00442-006-0381-8
Abstract
The aspen free-air CO2 and O3 enrichment (FACTS II–FACE) study in Rhinelander, Wisconsin, USA, is designed to understand the mechanisms by which young northern deciduous forest ecosystems respond to elevated atmospheric carbon dioxide (CO2) and elevated tropospheric ozone (O3) in a replicated, factorial, field experiment. Soil respiration is the second largest flux of carbon (C) in these ecosystems, and the objective of this study was to understand how soil respiration responded to the experimental treatments as these fast-growing stands of pure aspen and birch + aspen approached maximum leaf area. Rates of soil respiration were typically lowest in the elevated O3 treatment. Elevated CO2 significantly stimulated soil respiration (8–26%) compared to the control treatment in both community types over all three growing seasons. In years 6–7 of the experiment, the greatest rates of soil respiration occurred in the interaction treatment (CO2 + O3), and rates of soil respiration were 15–25% greater in this treatment than in the elevated CO2 treatment, depending on year and community type. Two of the treatments, elevated CO2 and elevated CO2 + O3, were fumigated with 13C-depleted CO2, and in these two treatments we used standard isotope mixing models to understand the proportions of new and old C in soil respiration. During the peak of the growing season, C fixed since the initiation of the experiment in 1998 (new C) accounted for 60–80% of total soil respiration. The isotope measurements independently confirmed that more new C was respired from the interaction treatment compared to the elevated CO2 treatment. A period of low soil moisture late in the 2003 growing season resulted in soil respiration with an isotopic signature 4–6‰ enriched in 13C compared to sample dates when the percentage soil moisture was higher. In 2004, an extended period of low soil moisture during August and early September, punctuated by a significant rainfall event, resulted in soil respiration that was temporarily 4–6‰ more depleted in 13C. Up to 50% of the Earth’s forests will see elevated concentrations of both CO2 and O3 in the coming decades and these interacting atmospheric trace gases stimulated soil respiration in this study.Keywords
This publication has 44 references indexed in Scilit:
- What have we learned from 15 years of free‐air CO2 enrichment (FACE)? A meta‐analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2New Phytologist, 2004
- Source–sink balance and carbon allocation below ground in plants exposed to ozoneNew Phytologist, 2003
- CARBON ISOTOPE RATIOS IN BELOWGROUND CARBON CYCLE PROCESSESEcological Applications, 2000
- Forest atmosphere carbon transfer and storage (FACTS-II) the aspen Free-air CO2 and O3 Enrichment (FACE) project: an overview.Published by USDA Forest Service ,2000
- Separation of Root Respiration from Total Soil Respiration Using Carbon‐13 Labeling during Free‐Air Carbon Dioxide Enrichment (FACE)Soil Science Society of America Journal, 1999
- DROUGHT REDUCES ROOT RESPIRATION IN SUGAR MAPLE FORESTSEcological Applications, 1998
- A meta-analysis of elevated CO 2 effects on woody plant mass, form, and physiologyOecologia, 1998
- Root growth and physiology of potted and field-grown trembling aspen exposed to tropospheric ozoneTree Physiology, 1996
- The stable isotopic composition and measurement of carbon in soil CO2Geochimica et Cosmochimica Acta, 1995
- On the isotopic composition of carbon in soil carbon dioxideGeochimica et Cosmochimica Acta, 1991