Long-term macronutrient stoichiometry of UK ombrotrophic peatlands.
In this paper we report new data on peat carbon (C), nitrogen (N) and phosphorus (P) concentrations and accumulation rates for 15 sites in the UK. Concentrations of C, N and P measured in peat from five ombrotrophic blanket mires, spanning 4000-10,000years to present were combined with existing nutrient data from ten Scottish ombrotrophic peat bogs to provide the first UK perspective on millennial scale macronutrient concentrations in ombrotrophic peats. Long-term average C, N and P concentrations (0-1.25m) for the UK are 54.8, 1.56 and 0.039wt%, of similar magnitude to the few published comparable sites worldwide. The uppermost peat (0-0.2m) is enriched in P and N (51.0, 1.86, and 0.070wt%) relative to the deeper peat (0.5-1.25m, 56.3, 1.39, and 0.027wt%). Long-term average (whole core) accumulation rates of C, N and P are 25.3±2.2gCm-2year-1(mean±SE), 0.70±0.09gNm-2year-1and 0.018±0.004gPm-2year-1, again similar to values reported elsewhere in the world. The two most significant findings are: 1) that a regression model of N concentration on P concentration and mean annual precipitation, based on global meta data for surface peat samples, can explain 54% of variance in N concentration in these UK peat profiles; and 2) budget calculations for the UK peat cores yield an estimate for long-term average N-fixation of 0.8gm-2year-1. Our UK results, and comparison with others sites, corroborate published estimates of N storage in northern boreal peatlands through the Holocene as ranging between 8 and 15Pg N. However, the observed correlation of N% with both mean annual precipitation and P concentration allows a potential bias in global estimates that do not take this into account. The peat sampling data set has been deposited at the NERC Data Centre (Toberman et al., 2016).
School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom. Electronic address: daniel.schillereff@kcl.ac.uk.
Daniel N
DN
Schillereff
School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom. Electronic address: jfb@liv.ac.uk.
John F
JF
Boyle
School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom. Electronic address: hannahtoberman@hotmail.com.
Hannah
H
Toberman
Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster LA1 4AP, United Kingdom. Electronic address: jesams@ceh.ac.uk.
Jessica L
JL
Adams
NERC Radiocarbon Facility (East Kilbride), Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride, Scotland G75 OQF, United Kingdom. Electronic address: charlotte.bryant@glasgow.ac.uk.
Charlotte L
CL
Bryant
School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom. Electronic address: rchiv@liv.ac.uk.
Richard C
RC
Chiverrell
The James Hutton Institute, Craigiebuckler, Aberdeen, Scotland AB15 8QH, United Kingdom. Electronic address: rachel.helliwell@hutton.ac.uk.
Rachel C
RC
Helliwell
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom. Electronic address: pkeenan@ceh.ac.uk.
Patrick
P
Keenan
The James Hutton Institute, Craigiebuckler, Aberdeen, Scotland AB15 8QH, United Kingdom. Electronic address: allan.lilly@hutton.ac.uk.
Allan
A
Lilly
Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster LA1 4AP, United Kingdom. Electronic address: et@ceh.ac.uk.
Edward
E
Tipping
Carbon; Holocene; Nitrogen; Ombrotrophic; Peat; Phosphorus; Stoichiometry