Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate
Understanding the climatic and biological factors that regulate soil carbon dioxide (CO2) efflux is crucial in peatlands because they contain a large proportion of terrestrial carbon (C). We predicted that rainfall reduction would increase soil CO2 efflux, and that cessation of below-ground allocati...
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| Format: | Article |
| Language: | English |
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International Mire Conservation Group and International Peatland Society
2016-02-01
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| Series: | Mires and Peat |
| Subjects: | |
| Online Access: | http://mires-and-peat.net/media/map17/map_17_01.pdf |
| _version_ | 1797705883057127424 |
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| author | U.H. Kritzler R.R.E. Artz D. Johnson |
| author_facet | U.H. Kritzler R.R.E. Artz D. Johnson |
| author_sort | U.H. Kritzler |
| collection | DOAJ |
| description | Understanding the climatic and biological factors that regulate soil carbon dioxide (CO2) efflux is crucial in peatlands because they contain a large proportion of terrestrial carbon (C). We predicted that rainfall reduction would increase soil CO2 efflux, and that cessation of below-ground allocation of recent plant assimilate would reduce soil CO2 efflux. These predictions were tested in the field using rainfall shelters that allowed a maximum of 40 % of rainfall onto 2 × 2 m plots by diverting rainwater from the shelter roofs with guttering, and by girdling stems of the dominant plant, Calluna vulgaris, for two years. We also used 13CO2-pulse labelling of intact monoliths at ambient CO2 concentrations to trace recent assimilate from plant shoots to roots, bulk soil, leachate, dissolved organic carbon (DOC) and soil CO2 efflux . Soil CO2 efflux in the sheltered plots increased in Year 1 but not in Year 2, and we found a positive relationship between soil CO2 efflux and water table depth. Our data indicate that lowering the water table below a critical threshold (15–20 cm) affects soil CO2 efflux. Girdling of C. vulgaris shoots resulted in no measurable reduction in soil CO2 efflux, while only ~3 % of 13C fixed by shoots was recovered in soil CO2 efflux and DOC in the 20 days after labelling. Our findings show that below-ground allocation of recent assimilate from C. vulgaris plants > 6 years old has little impact on soil CO2 efflux. |
| first_indexed | 2024-03-12T05:42:54Z |
| format | Article |
| id | doaj.art-d5c43ad144e5472a80acfe2684434647 |
| institution | Directory Open Access Journal |
| issn | 1819-754X |
| language | English |
| last_indexed | 2024-03-12T05:42:54Z |
| publishDate | 2016-02-01 |
| publisher | International Mire Conservation Group and International Peatland Society |
| record_format | Article |
| series | Mires and Peat |
| spelling | doaj.art-d5c43ad144e5472a80acfe26844346472023-09-03T05:52:28ZengInternational Mire Conservation Group and International Peatland SocietyMires and Peat1819-754X2016-02-01170111410.19189/MaP.2015.OMB.203Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilateU.H. Kritzler0R.R.E. Artz1D. Johnson2University of Aberdeen and James Hutton Institute, Aberdeen, UKJames Hutton Institute, Aberdeen, UKInstitute of Biological & Environmental Sciences, University of Aberdeen, UKUnderstanding the climatic and biological factors that regulate soil carbon dioxide (CO2) efflux is crucial in peatlands because they contain a large proportion of terrestrial carbon (C). We predicted that rainfall reduction would increase soil CO2 efflux, and that cessation of below-ground allocation of recent plant assimilate would reduce soil CO2 efflux. These predictions were tested in the field using rainfall shelters that allowed a maximum of 40 % of rainfall onto 2 × 2 m plots by diverting rainwater from the shelter roofs with guttering, and by girdling stems of the dominant plant, Calluna vulgaris, for two years. We also used 13CO2-pulse labelling of intact monoliths at ambient CO2 concentrations to trace recent assimilate from plant shoots to roots, bulk soil, leachate, dissolved organic carbon (DOC) and soil CO2 efflux . Soil CO2 efflux in the sheltered plots increased in Year 1 but not in Year 2, and we found a positive relationship between soil CO2 efflux and water table depth. Our data indicate that lowering the water table below a critical threshold (15–20 cm) affects soil CO2 efflux. Girdling of C. vulgaris shoots resulted in no measurable reduction in soil CO2 efflux, while only ~3 % of 13C fixed by shoots was recovered in soil CO2 efflux and DOC in the 20 days after labelling. Our findings show that below-ground allocation of recent assimilate from C. vulgaris plants > 6 years old has little impact on soil CO2 efflux.http://mires-and-peat.net/media/map17/map_17_01.pdfCalluna vulgariscarbon cycle13CO2 pulse labellingdegraded peat boggirdling |
| spellingShingle | U.H. Kritzler R.R.E. Artz D. Johnson Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate Mires and Peat Calluna vulgaris carbon cycle 13CO2 pulse labelling degraded peat bog girdling |
| title | Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| title_full | Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| title_fullStr | Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| title_full_unstemmed | Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| title_short | Soil CO2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| title_sort | soil co2 efflux in a degraded raised bog is regulated by water table depth rather than recent plant assimilate |
| topic | Calluna vulgaris carbon cycle 13CO2 pulse labelling degraded peat bog girdling |
| url | http://mires-and-peat.net/media/map17/map_17_01.pdf |
| work_keys_str_mv | AT uhkritzler soilco2effluxinadegradedraisedbogisregulatedbywatertabledepthratherthanrecentplantassimilate AT rreartz soilco2effluxinadegradedraisedbogisregulatedbywatertabledepthratherthanrecentplantassimilate AT djohnson soilco2effluxinadegradedraisedbogisregulatedbywatertabledepthratherthanrecentplantassimilate |