Plant functional types and temperature control carbon input via roots in peatland soils

Lilli Zeh, Juul Limpens, Björn Erhagen, Luca Bragazza, Karsten Kalbitz

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)

Abstract

Aims: Northern peatlands store large amounts of soil organic carbon (C) that can be very sensitive to ongoing global warming. Recently it has been shown that temperature-enhanced growth of vascular plants in these typically moss-dominated ecosystems may promote microbial peat decomposition by increased C input via root exudates. To what extent different plant functional types (PFT) and soil temperature interact in controlling root C input is still unclear. In this study we explored how root C input is related to the presence of ericoid shrubs (shrubs) and graminoid sedges (sedges) by means of a factorial plant clipping experiment (= PFT effect) in two peatlands located at different altitude (= temperature effect). Methods: By selective clipping of shrub and sedge shoots in mixed vegetation at two Alpine peatland sites we interrupted the above- to belowground translocation of C, thus temporarily inhibiting root C release. Subsequent measurements of soil respiration, dissolved organic carbon (DOC) concentration and stable isotope composition ( 13 C) of DOC in pore water were used as proxies to estimate the above- to belowground transfer of C by different PFT. Results: We found that soil respiration rates and DOC concentrations temporarily decreased within 24 h after clipping, with the decrease in soil respiration being most pronounced at the 1.4 °C warmer peatland after clipping shrubs. The transient drop in DOC concentration coincided with a shift towards a heavier C isotope signature, indicating that the decrease was associated with inhibition of a light C source that we attribute to root exudates. Together these results imply that shrubs translocated more C into the peat than sedges, particularly at higher temperature. Conclusions: We showed that plant functional type and temperature interact in controlling root C input under field conditions in peatlands. Our results provide a mechanistic evidence that shrubs may potentially promote the release of stored soil C through root-derived C input.

LanguageEnglish
Pages19-38
JournalPlant and Soil
Volume438
Issue number1-2
Early online date4 Mar 2019
DOIs
Publication statusPublished - May 2019

Fingerprint

peatlands
peatland
shrubs
shrub
dissolved organic carbon
clipping
carbon
Cyperaceae
soil respiration
soil
temperature
root exudates
peat
sedge
soil organic carbon
vascular plants
global warming
soil temperature
stable isotopes
mosses and liverworts

Keywords

  • Dissolved organic carbon
  • Peatland
  • Root carbon input
  • Sedges
  • Shrubs
  • Soil respiration
  • Vascular plants
  • δ C

Cite this

Zeh, Lilli ; Limpens, Juul ; Erhagen, Björn ; Bragazza, Luca ; Kalbitz, Karsten. / Plant functional types and temperature control carbon input via roots in peatland soils. In: Plant and Soil. 2019 ; Vol. 438, No. 1-2. pp. 19-38.
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title = "Plant functional types and temperature control carbon input via roots in peatland soils",
abstract = "Aims: Northern peatlands store large amounts of soil organic carbon (C) that can be very sensitive to ongoing global warming. Recently it has been shown that temperature-enhanced growth of vascular plants in these typically moss-dominated ecosystems may promote microbial peat decomposition by increased C input via root exudates. To what extent different plant functional types (PFT) and soil temperature interact in controlling root C input is still unclear. In this study we explored how root C input is related to the presence of ericoid shrubs (shrubs) and graminoid sedges (sedges) by means of a factorial plant clipping experiment (= PFT effect) in two peatlands located at different altitude (= temperature effect). Methods: By selective clipping of shrub and sedge shoots in mixed vegetation at two Alpine peatland sites we interrupted the above- to belowground translocation of C, thus temporarily inhibiting root C release. Subsequent measurements of soil respiration, dissolved organic carbon (DOC) concentration and stable isotope composition ( 13 C) of DOC in pore water were used as proxies to estimate the above- to belowground transfer of C by different PFT. Results: We found that soil respiration rates and DOC concentrations temporarily decreased within 24 h after clipping, with the decrease in soil respiration being most pronounced at the 1.4 °C warmer peatland after clipping shrubs. The transient drop in DOC concentration coincided with a shift towards a heavier C isotope signature, indicating that the decrease was associated with inhibition of a light C source that we attribute to root exudates. Together these results imply that shrubs translocated more C into the peat than sedges, particularly at higher temperature. Conclusions: We showed that plant functional type and temperature interact in controlling root C input under field conditions in peatlands. Our results provide a mechanistic evidence that shrubs may potentially promote the release of stored soil C through root-derived C input.",
keywords = "Dissolved organic carbon, Peatland, Root carbon input, Sedges, Shrubs, Soil respiration, Vascular plants, δ C",
author = "Lilli Zeh and Juul Limpens and Bj{\"o}rn Erhagen and Luca Bragazza and Karsten Kalbitz",
year = "2019",
month = "5",
doi = "10.1007/s11104-019-03958-6",
language = "English",
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Plant functional types and temperature control carbon input via roots in peatland soils. / Zeh, Lilli; Limpens, Juul; Erhagen, Björn; Bragazza, Luca; Kalbitz, Karsten.

In: Plant and Soil, Vol. 438, No. 1-2, 05.2019, p. 19-38.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Plant functional types and temperature control carbon input via roots in peatland soils

AU - Zeh, Lilli

AU - Limpens, Juul

AU - Erhagen, Björn

AU - Bragazza, Luca

AU - Kalbitz, Karsten

PY - 2019/5

Y1 - 2019/5

N2 - Aims: Northern peatlands store large amounts of soil organic carbon (C) that can be very sensitive to ongoing global warming. Recently it has been shown that temperature-enhanced growth of vascular plants in these typically moss-dominated ecosystems may promote microbial peat decomposition by increased C input via root exudates. To what extent different plant functional types (PFT) and soil temperature interact in controlling root C input is still unclear. In this study we explored how root C input is related to the presence of ericoid shrubs (shrubs) and graminoid sedges (sedges) by means of a factorial plant clipping experiment (= PFT effect) in two peatlands located at different altitude (= temperature effect). Methods: By selective clipping of shrub and sedge shoots in mixed vegetation at two Alpine peatland sites we interrupted the above- to belowground translocation of C, thus temporarily inhibiting root C release. Subsequent measurements of soil respiration, dissolved organic carbon (DOC) concentration and stable isotope composition ( 13 C) of DOC in pore water were used as proxies to estimate the above- to belowground transfer of C by different PFT. Results: We found that soil respiration rates and DOC concentrations temporarily decreased within 24 h after clipping, with the decrease in soil respiration being most pronounced at the 1.4 °C warmer peatland after clipping shrubs. The transient drop in DOC concentration coincided with a shift towards a heavier C isotope signature, indicating that the decrease was associated with inhibition of a light C source that we attribute to root exudates. Together these results imply that shrubs translocated more C into the peat than sedges, particularly at higher temperature. Conclusions: We showed that plant functional type and temperature interact in controlling root C input under field conditions in peatlands. Our results provide a mechanistic evidence that shrubs may potentially promote the release of stored soil C through root-derived C input.

AB - Aims: Northern peatlands store large amounts of soil organic carbon (C) that can be very sensitive to ongoing global warming. Recently it has been shown that temperature-enhanced growth of vascular plants in these typically moss-dominated ecosystems may promote microbial peat decomposition by increased C input via root exudates. To what extent different plant functional types (PFT) and soil temperature interact in controlling root C input is still unclear. In this study we explored how root C input is related to the presence of ericoid shrubs (shrubs) and graminoid sedges (sedges) by means of a factorial plant clipping experiment (= PFT effect) in two peatlands located at different altitude (= temperature effect). Methods: By selective clipping of shrub and sedge shoots in mixed vegetation at two Alpine peatland sites we interrupted the above- to belowground translocation of C, thus temporarily inhibiting root C release. Subsequent measurements of soil respiration, dissolved organic carbon (DOC) concentration and stable isotope composition ( 13 C) of DOC in pore water were used as proxies to estimate the above- to belowground transfer of C by different PFT. Results: We found that soil respiration rates and DOC concentrations temporarily decreased within 24 h after clipping, with the decrease in soil respiration being most pronounced at the 1.4 °C warmer peatland after clipping shrubs. The transient drop in DOC concentration coincided with a shift towards a heavier C isotope signature, indicating that the decrease was associated with inhibition of a light C source that we attribute to root exudates. Together these results imply that shrubs translocated more C into the peat than sedges, particularly at higher temperature. Conclusions: We showed that plant functional type and temperature interact in controlling root C input under field conditions in peatlands. Our results provide a mechanistic evidence that shrubs may potentially promote the release of stored soil C through root-derived C input.

KW - Dissolved organic carbon

KW - Peatland

KW - Root carbon input

KW - Sedges

KW - Shrubs

KW - Soil respiration

KW - Vascular plants

KW - δ C

U2 - 10.1007/s11104-019-03958-6

DO - 10.1007/s11104-019-03958-6

M3 - Article

VL - 438

SP - 19

EP - 38

JO - Plant and Soil

T2 - Plant and Soil

JF - Plant and Soil

SN - 0032-079X

IS - 1-2

ER -