In:
Global Change Biology, Wiley, Vol. 14, No. 11 ( 2008-11), p. 2539-2547
Abstract:
The environmental importance of methyl bromide (CH 3 Br) arises from its contribution to stratospheric ozone loss processes and, as a consequence, its emissions from anthropogenic sources are subject to the Montreal Protocol. A better understanding of the natural budget of CH 3 Br is required for assessing the benefit of anthropogenic emission reductions and for understanding any potential effects of environmental change on global CH 3 Br concentrations. Measurements of CH 3 Br flux in temperate woodland ecosystems, in particular, are very sparse, yet these cover a large fraction of terrestrial land surface. Results presented here from 18 months of field measurements of CH 3 Br fluxes in four static flux chambers in a woodland in Scotland and from enclosures of rotting wood and deciduous and coniferous leaf litter suggest net emissions from temperate woodlands. Net CH 3 Br fluxes in the woodland varied between the chambers, fluctuating between net uptake and net emissions (−73 to 279 ng m −2 h −1 across 161 individual measurements), and with no strong seasonality, but with time‐averaged net emission overall [27±57 (1 SD)] ng m −2 h −1 ]. This work demonstrates that scale‐up needs to be based on sufficient individual measurements to provide a reasonably constrained estimate of the long‐term mean. Mean (±1 SD) net CH 3 Br emissions from deciduous and coniferous leaf litter were 43 (±33) ng kg −1 (dry weight) h −1 and 80 (±37) ng kg −1 (dry weight) h −1 , respectively, and ∼1–2 ng kg −1 (fresh weight) h −1 from rotting woody litter. Despite the intrinsic variability, data obtained here consistently point to the conclusion that the temperate forest soil/litter ecosystem is a net source of CH 3 Br to the atmosphere.
Type of Medium:
Online Resource
ISSN:
1354-1013
,
1365-2486
DOI:
10.1111/gcb.2008.14.issue-11
DOI:
10.1111/j.1365-2486.2008.01676.x
Language:
English
Publisher:
Wiley
Publication Date:
2008
detail.hit.zdb_id:
2020313-5
SSG:
12
