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Title: Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon
Authors: Evans, Chris D.
Page, Susan E.
Jones, Tim
Moore, Sam
Gauci, Vincent
Laiho, Raija
Hruska, Jakub
Allott, Tim E. H
Billett, Michael F.
Tipping, Ed
Freeman, Chris
Garnett, Mark H.
First Published: 13-Nov-2014
Publisher: American Geophysical Union
Citation: Global Biogeochemical Cycles, 2014, 28 (11), pp. 1215 - 1234
Abstract: Carbon sequestration and storage in peatlands rely on consistently high water tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO[subscript 2] sinks to large CO[subscript 2] sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon ([superscript 14]C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but with marked differences related to peat type. Very low DOC-[superscript 14]C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; [superscript 14]C measurements from UK blanket bogs suggest that exported DOC remains young (<50 years) despite drainage. Boreal and temperate fens and raised bogs in Finland and the Czech Republic showed intermediate sensitivity. We attribute observed differences to physical and climatic differences between peatlands, in particular, hydraulic conductivity and temperature, as well as the extent of disturbance associated with drainage, notably land use changes in the tropics. Data from the UK Peak District, an area where air pollution and intensive land management have triggered Sphagnum loss and peat erosion, suggest that additional anthropogenic pressures may trigger fluvial loss of much older (>500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.
DOI Link: 10.1002/2013GB004782
ISSN: 0886-6236
eISSN: 1944-9224
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2014, American Geophysical Union. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.
Appears in Collections:Published Articles, Dept. of Geography

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