McNamara N P, Plant T, Oakley S, Ward S, Wood C, Ostle N
Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, United Kingdom.
Sci Total Environ. 2008 Oct 15;404(2-3):354-60. doi: 10.1016/j.scitotenv.2008.03.015. Epub 2008 May 27.
Peatlands are long term carbon catchments that sink atmospheric carbon dioxide (CO(2)) and source methane (CH(4)). In the uplands of the United Kingdom ombrotrophic blanket peatlands commonly exist within Calluna vulgaris (L.) dominated moorland ecosystems. These landscapes contain a range of topographical features that influence local hydrology, climate and plant community composition. In this study we examined the variation in ecosystem CO(2) respiration and net CH(4) fluxes from typical plant-soil systems in dendritic drainage gullies and adjacent blanket peat during the growing season. Typically, Eriophorum spp., Sphagnum spp. and mixed grasses occupied gullies while C. vulgaris dominated in adjacent blanket peat. Gross CO(2) respiration was highest in the areas of Eriophorum spp. (650+/-140 mg CO(2) m(-2) h(-1)) compared to those with Sphagnum spp. (338+/-49 mg CO(2) m(-2) h(-1)), mixed grasses (342+/-91 mg CO(2) m(-2) h(-1)) and C. vulgaris (174+/-63 mg CO(2) m(-2) h(-1)). Measurements of the net CH(4) flux showed higher fluxes from the Eriophorum spp (2.2+/-0.6 mg CH(4) m(-2) h(-1)) locations compared to the Sphagnum spp. (0.6+/-0.4 mg CH(4) m(-2) h(-1)), mixed grasses (0.1+/-0.1 mg CH(4) m(-2) h(-1)) and a negligible flux detected from C. vulgaris (0.0+/-0.0 mg CH(4) m(-2) h(-1)) locations. A GIS approach was applied to calculate the contribution of gullies to landscape scale greenhouse gas fluxes. Findings from the Moor House National Nature Reserve in the UK showed that although gullies occupied only 9.3% of the total land surface, gullies accounted for 95.8% and 21.6% of the peatland net CH(4) and CO(2) respiratory fluxes, respectively. The implication of these findings is that the relative contribution of characteristic gully systems need to be considered in estimates of landscape scale peatland greenhouse gas fluxes.
泥炭地是长期的碳汇，吸收大气中的二氧化碳（CO₂）并释放甲烷（CH₄）。在英国高地，以帚石楠（Calluna vulgaris (L.)）为主导的泥炭藓沼泽泥炭地通常存在于石南灌丛生态系统中。这些地貌包含一系列影响当地水文、气候和植物群落组成的地形特征。在本研究中，我们调查了生长季节期间，树枝状排水沟壑和相邻泥炭藓沼泽中典型植物 - 土壤系统的生态系统CO₂呼吸和CH₄净通量的变化。通常，羊胡子草属（Eriophorum spp.）、泥炭藓属（Sphagnum spp.）和混合草类占据沟壑，而帚石楠在相邻的泥炭藓沼泽中占主导地位。与泥炭藓属区域（338±49 mg CO₂ m⁻² h⁻¹）、混合草类区域（342±91 mg CO₂ m⁻² h⁻¹）和帚石楠区域（174±63 mg CO₂ m⁻² h⁻¹）相比，羊胡子草属区域的总CO₂呼吸量最高（650±140 mg CO₂ m⁻² h⁻¹）。CH₄净通量测量结果表明，羊胡子草属区域（2.2±0.6 mg CH₄ m⁻² h⁻¹）的通量高于泥炭藓属区域（0.6±0.4 mg CH₄ m⁻² h⁻¹）、混合草类区域（0.1±0.1 mg CH₄ m⁻² h⁻¹），而帚石楠区域检测到的通量可忽略不计（0.0±0.0 mg CH₄ m⁻² h⁻¹）。采用地理信息系统（GIS）方法计算沟壑对景观尺度温室气体通量的贡献。英国莫尔豪斯国家自然保护区的研究结果表明，尽管沟壑仅占陆地总面积的9.3%，但沟壑分别占泥炭地CH₄净通量和CO₂呼吸通量的95.8%和21.6%。这些研究结果表明，在估算景观尺度泥炭地温室气体通量时，需要考虑典型沟壑系统的相对贡献。
