Evans, Christopher
- Centre for Ecology and Hydrology (CEH)
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 CO2 sinks to large CO2 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 (C-14) 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-C-14 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; C-14 measurements from UK blanket bogs suggest that exported DOC remains young (500year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.
Keywords
peatland; drainage; dissolved organic carbon; radiocarbon
Published in
Global Biogeochemical Cycles
2014, volume: 28, number: 11, pages: 1215-1234
Publisher: AMER GEOPHYSICAL UNION
SLU Authors
UKÄ Subject classification
Geosciences, Multidisciplinary
Publication identifier
- DOI: https://doi.org/10.1002/2013GB004782
Permanent link to this page (URI)
https://res.slu.se/id/publ/87809