Dependence of ombrotrophic peat nitrogen on phosphorus and climate

作者：Toberman Hannah; Tipping Edward^*; Boyle John F; Helliwell Rachel C; Lilly Allan; Henrys Peter A

来源：Biogeochemistry, 2015, 125(1): 11-20.

DOI：10.1007/s10533-015-0117-0

• Peat
• Ombrotrophic
• Nitrogen
• Phosphorus
• Climate
• Nitrogen deposition

Nitrogen (N) is a key, possibly limiting, nutrient in ombrotrophic peat ecosystems, and enrichment by pollutant N in atmospheric deposition (N-dep, g m(-2) a(-1)) is of concern with regard to peatland damage. We collated data on the N content of surface (depth a parts per thousand currency sign25 cm, mean 15 cm) ombrotrophic peat (N-sp) for 215 sites in the UK and 62 other sites around the world, including boreal, temperate and tropical locations (wider global data), and found N-sp to range from 0.5 to 4 %. We examined the dependences of N-sp on surface peat phosphorus (P) content (P-sp), mean annual precipitation (MAP), mean annual temperature (MAT) and N-dep. Linear regression on individual independent variables showed highly significant (p < 0.001) correlations of N-sp with P-sp(r(2) = 0.23) and MAP (r(2) = 0.14), and significant (p < 0.01) but weaker correlations with MAT (r(2) = 0.03) and N-dep (r(2) = 0.03). A multiple regression model using log-transformed values explained 36 % of the variance of the UK data, 84 % of the variance of the wider global data, and 47 % of the variance of the combined data, all with high significance (p < 0.001). In all three cases, most of the variance was explained by P-sp and MAP, but in view of a positive correlation between MAP and MAT for many of the sites, a role for MAT in controlling N-sp cannot be ruled out. There is little evidence for an effect of N-dep on N-sp. The results point to a key role of P in N fixation, and thereby C fixation, in ombrotrophic peats.

• 出版日期2015-8