Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest
<p>Soil respiration (<span class="inline-formula"><i>R</i><sub>s</sub></span>), the flow of <span class="inline-formula">CO<sub>2</sub></span> from the soil surface to the atmosphere, is one of the largest carbon f...
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doaj-49b7d3e3267948a895961cc7a6f914dc2020-11-25T00:28:41ZengCopernicus PublicationsBiogeosciences1726-41701726-41892020-02-011777178010.5194/bg-17-771-2020Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forestS. C. Pennington0N. G. McDowell1J. P. Megonigal2J. C. Stegen3B. Bond-Lamberty4Joint Global Change Research Institute, Pacific Northwest National Laboratory, 5825 University Research Ct. #3500, College Park, MD 20740, USAPacific Northwest National Laboratory, Biological Sciences Division, Richland, WA 99354, USASmithsonian Environmental Research Center, Edgewater, MD 21037, USAPacific Northwest National Laboratory, Biological Sciences Division, Richland, WA 99354, USAJoint Global Change Research Institute, Pacific Northwest National Laboratory, 5825 University Research Ct. #3500, College Park, MD 20740, USA<p>Soil respiration (<span class="inline-formula"><i>R</i><sub>s</sub></span>), the flow of <span class="inline-formula">CO<sub>2</sub></span> from the soil surface to the atmosphere, is one of the largest carbon fluxes in the terrestrial biosphere. The spatial variability of <span class="inline-formula"><i>R</i><sub>s</sub></span> is both large and poorly understood, limiting our ability to robustly scale it in space. One factor in <span class="inline-formula"><i>R</i><sub>s</sub></span> spatial variability is the autotrophic contribution from plant roots, but it is uncertain how the presence of plants affects the magnitude and temperature sensitivity of <span class="inline-formula"><i>R</i><sub>s</sub></span>. This study used 1 year of <span class="inline-formula"><i>R</i><sub>s</sub></span> measurements to examine the effect of localized basal area on <span class="inline-formula"><i>R</i><sub>s</sub></span> in the growing and dormant seasons, as well as during moisture-limited times, in a temperate, coastal, deciduous forest in eastern Maryland, USA. In a linear mixed-effects model, tree basal area within a 5 m radius (BA<span class="inline-formula"><sub>5</sub></span>) exerted a significant positive effect on the temperature sensitivity of soil respiration. Soil moisture was the dominant control on <span class="inline-formula"><i>R</i><sub>s</sub></span> during the dry portions of the year, while soil moisture, temperature, and BA<span class="inline-formula"><sub>5</sub></span> all exerted significant effects on <span class="inline-formula"><i>R</i><sub>s</sub></span> in wetter periods. Our results suggest that autotrophic respiration is more sensitive to temperature than heterotrophic respiration at these sites, although we did not measure these source fluxes directly, and that soil respiration is highly moisture sensitive, even in a record-rainfall year. The <span class="inline-formula"><i>R</i><sub>s</sub></span> flux magnitudes (0.46–15.0 <span class="inline-formula">µ</span>mol m<span class="inline-formula"><sup>−2</sup></span> s<span class="inline-formula"><sup>−1</sup></span>) and variability (coefficient of variability 10 %–23 % across plots) observed in this study were comparable to values observed in similar forests. Six <span class="inline-formula"><i>R</i><sub>s</sub></span> observations would be required in order to estimate the mean across all study sites to within 50 %, and 518 would be required in order to estimate it to within 5 %, with 95 % confidence. A better understanding of the spatial interactions between plants and microbes, as well as the strength and speed of above- and belowground coupling, is necessary to link these processes with large-scale soil-to-atmosphere C fluxes.</p>https://www.biogeosciences.net/17/771/2020/bg-17-771-2020.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
S. C. Pennington N. G. McDowell J. P. Megonigal J. C. Stegen B. Bond-Lamberty |
spellingShingle |
S. C. Pennington N. G. McDowell J. P. Megonigal J. C. Stegen B. Bond-Lamberty Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest Biogeosciences |
author_facet |
S. C. Pennington N. G. McDowell J. P. Megonigal J. C. Stegen B. Bond-Lamberty |
author_sort |
S. C. Pennington |
title |
Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
title_short |
Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
title_full |
Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
title_fullStr |
Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
title_full_unstemmed |
Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
title_sort |
localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest |
publisher |
Copernicus Publications |
series |
Biogeosciences |
issn |
1726-4170 1726-4189 |
publishDate |
2020-02-01 |
description |
<p>Soil respiration (<span class="inline-formula"><i>R</i><sub>s</sub></span>), the flow of <span class="inline-formula">CO<sub>2</sub></span> from the soil
surface to the atmosphere, is one of the largest carbon fluxes in the
terrestrial biosphere. The spatial variability of <span class="inline-formula"><i>R</i><sub>s</sub></span> is both large and
poorly understood, limiting our ability to robustly scale it in space. One
factor in <span class="inline-formula"><i>R</i><sub>s</sub></span> spatial variability is the autotrophic contribution from
plant roots, but it is uncertain how the presence of plants affects the
magnitude and temperature sensitivity of <span class="inline-formula"><i>R</i><sub>s</sub></span>. This study used 1 year of <span class="inline-formula"><i>R</i><sub>s</sub></span> measurements to examine the effect of localized basal area on
<span class="inline-formula"><i>R</i><sub>s</sub></span> in the growing and dormant seasons, as well as during
moisture-limited times, in a temperate, coastal, deciduous forest in eastern
Maryland, USA. In a linear mixed-effects model, tree basal area within a 5 m
radius (BA<span class="inline-formula"><sub>5</sub></span>) exerted a significant positive effect on the temperature
sensitivity of soil respiration. Soil moisture was the dominant control on
<span class="inline-formula"><i>R</i><sub>s</sub></span> during the dry portions of the year, while soil moisture,
temperature, and BA<span class="inline-formula"><sub>5</sub></span> all exerted significant effects on <span class="inline-formula"><i>R</i><sub>s</sub></span> in
wetter periods. Our results suggest that autotrophic respiration is more
sensitive to temperature than heterotrophic respiration at these sites,
although we did not measure these source fluxes directly, and that soil
respiration is highly moisture sensitive, even in a record-rainfall year.
The <span class="inline-formula"><i>R</i><sub>s</sub></span> flux magnitudes (0.46–15.0 <span class="inline-formula">µ</span>mol m<span class="inline-formula"><sup>−2</sup></span> s<span class="inline-formula"><sup>−1</sup></span>) and
variability (coefficient of variability 10 %–23 % across plots) observed
in this study were comparable to values observed in similar forests. Six
<span class="inline-formula"><i>R</i><sub>s</sub></span> observations would be required in order to estimate the mean across
all study sites to within 50 %, and 518 would be required in order to
estimate it to within 5 %, with 95 % confidence. A better understanding
of the spatial interactions between plants and microbes, as well as the
strength and speed of above- and belowground coupling, is necessary to
link these processes with large-scale soil-to-atmosphere C fluxes.</p> |
url |
https://www.biogeosciences.net/17/771/2020/bg-17-771-2020.pdf |
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