Details
| Original language | English |
|---|---|
| Pages (from-to) | 5341-5355 |
| Number of pages | 15 |
| Journal | Global change biology |
| Volume | 27 |
| Issue number | 20 |
| Publication status | Published - Oct 2021 |
Abstract
Global warming is accelerating the decomposition of soil organic matter (SOM). When predicting the net SOM dynamics in response to warming, there are considerable uncertainties owing to experimental limitations. Long-term in situ whole-profile soil warming studies are particularly rare. This study used a long-term, naturally occurring geothermal gradient in Yukon, Canada, to investigate the warming effects on SOM in a forest ecosystem. Soils were sampled along this thermosequence which exhibited warming of up to 7.7℃; samples were collected to a depth of 80 cm and analysed for soil organic carbon (SOC) and nitrogen (N) content, and estimates made of SOC stock and fractions. Potential litter decomposition rates as a function of soil temperature and depth were observed for a 1-year period using buried teabags and temperature loggers. The SOC in the topsoil (0–20 cm) and subsoil (20–80 cm) responded similar to warming. A negative relationship was found between soil temperature and whole-profile SOC stocks, with a total loss of 27% between the warmest and reference plots, and a relative loss of 3%℃ −1. SOC losses were restricted to the particulate organic matter (POM) and dissolved organic carbon (DOC) fractions with net whole-profile depletions. Losses in POM-C accounted for the largest share of the total SOC losses. In contrast to SOC, N was not lost from the soil as a result of warming, but was redistributed with a relatively large accumulation in the silt and clay fraction (+40%). This suggests an immobilization of N by microbes building up in mineral-associated organic matter. These results confirm that soil warming accelerates SOC turnover throughout the profile and C is lost in both the topsoil and subsoil. Since N stocks remained constant with warming, SOM stoichiometry changed considerably and this in turn could affect C cycling through changes in microbial metabolism.
Keywords
- Canada, Takhini hot springs, fractionation, soil organic matter, soil warming, teabags, thermosequence, whole-profile
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Science(all)
- Global and Planetary Change
- Environmental Science(all)
- Ecology
- Environmental Science(all)
- Environmental Chemistry
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In: Global change biology, Vol. 27, No. 20, 10.2021, p. 5341-5355.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Long‐term geothermal warming reduced stocks of carbon but not nitrogen in a subarctic forest soil
AU - Peplau, Tino
AU - Schroeder, Julia
AU - Gregorich, Edward
AU - Poeplau, Christopher
N1 - Publisher Copyright: © 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd.
PY - 2021/10
Y1 - 2021/10
N2 - Global warming is accelerating the decomposition of soil organic matter (SOM). When predicting the net SOM dynamics in response to warming, there are considerable uncertainties owing to experimental limitations. Long-term in situ whole-profile soil warming studies are particularly rare. This study used a long-term, naturally occurring geothermal gradient in Yukon, Canada, to investigate the warming effects on SOM in a forest ecosystem. Soils were sampled along this thermosequence which exhibited warming of up to 7.7℃; samples were collected to a depth of 80 cm and analysed for soil organic carbon (SOC) and nitrogen (N) content, and estimates made of SOC stock and fractions. Potential litter decomposition rates as a function of soil temperature and depth were observed for a 1-year period using buried teabags and temperature loggers. The SOC in the topsoil (0–20 cm) and subsoil (20–80 cm) responded similar to warming. A negative relationship was found between soil temperature and whole-profile SOC stocks, with a total loss of 27% between the warmest and reference plots, and a relative loss of 3%℃ −1. SOC losses were restricted to the particulate organic matter (POM) and dissolved organic carbon (DOC) fractions with net whole-profile depletions. Losses in POM-C accounted for the largest share of the total SOC losses. In contrast to SOC, N was not lost from the soil as a result of warming, but was redistributed with a relatively large accumulation in the silt and clay fraction (+40%). This suggests an immobilization of N by microbes building up in mineral-associated organic matter. These results confirm that soil warming accelerates SOC turnover throughout the profile and C is lost in both the topsoil and subsoil. Since N stocks remained constant with warming, SOM stoichiometry changed considerably and this in turn could affect C cycling through changes in microbial metabolism.
AB - Global warming is accelerating the decomposition of soil organic matter (SOM). When predicting the net SOM dynamics in response to warming, there are considerable uncertainties owing to experimental limitations. Long-term in situ whole-profile soil warming studies are particularly rare. This study used a long-term, naturally occurring geothermal gradient in Yukon, Canada, to investigate the warming effects on SOM in a forest ecosystem. Soils were sampled along this thermosequence which exhibited warming of up to 7.7℃; samples were collected to a depth of 80 cm and analysed for soil organic carbon (SOC) and nitrogen (N) content, and estimates made of SOC stock and fractions. Potential litter decomposition rates as a function of soil temperature and depth were observed for a 1-year period using buried teabags and temperature loggers. The SOC in the topsoil (0–20 cm) and subsoil (20–80 cm) responded similar to warming. A negative relationship was found between soil temperature and whole-profile SOC stocks, with a total loss of 27% between the warmest and reference plots, and a relative loss of 3%℃ −1. SOC losses were restricted to the particulate organic matter (POM) and dissolved organic carbon (DOC) fractions with net whole-profile depletions. Losses in POM-C accounted for the largest share of the total SOC losses. In contrast to SOC, N was not lost from the soil as a result of warming, but was redistributed with a relatively large accumulation in the silt and clay fraction (+40%). This suggests an immobilization of N by microbes building up in mineral-associated organic matter. These results confirm that soil warming accelerates SOC turnover throughout the profile and C is lost in both the topsoil and subsoil. Since N stocks remained constant with warming, SOM stoichiometry changed considerably and this in turn could affect C cycling through changes in microbial metabolism.
KW - Canada
KW - Takhini hot springs
KW - fractionation
KW - soil organic matter
KW - soil warming
KW - teabags
KW - thermosequence
KW - whole-profile
UR - http://www.scopus.com/inward/record.url?scp=85109391331&partnerID=8YFLogxK
U2 - 10.1111/gcb.15754
DO - 10.1111/gcb.15754
M3 - Article
VL - 27
SP - 5341
EP - 5355
JO - Global change biology
JF - Global change biology
SN - 1354-1013
IS - 20
ER -