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The stoichiometry of carbon and nutrients in peat formation
Author(s) -
Wang Meng,
Moore Tim R.,
Talbot Julie,
Riley John L.
Publication year - 2015
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2014gb005000
Subject(s) - peat , bog , nutrient , litter , biogeochemical cycle , vegetation (pathology) , plant litter , phosphorus , environmental chemistry , chemistry , carbon fibers , environmental science , ecology , biology , medicine , materials science , organic chemistry , pathology , composite number , composite material
Northern peatlands have stored large amounts (~500 Pg) of carbon (C) since the last glaciation. Combined with peat C are nutrients such as nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and potassium (K), each of which plays an important role in plant production, litter decomposition, and the biogeochemical functioning of peatlands. Yet little attention has been given to the amounts of these nutrients stored in northern peatlands and their stoichiometry with C. Here we use data on nutrient concentrations in over 400 peat profiles in Ontario, Canada, representing bogs, fens, and swamps and their vegetation. We show that the C:N ratio is high (>40:1) in vegetation and litter but declines through the peat profiles to reach ratios between 22:1 and 29:1 in peat below 50 cm. In contrast, the C:P ratio rises from vegetation and litter (500:1 to 1300:1) to 1500:1 to 2000:1 in the lower part of the peat profile. Ratios of C to Ca, Mg, and K vary with peatland type. Most of these stoichiometric changes occur in the early stages of organic matter decomposition, where the litter structure remains intact. We estimate that ~18 Pg of N has been stored in northern peatlands since deglaciation, reflecting high N accumulation rates (~0.8 g m −2 yr −1 ), whereas P accumulation is small (~0.3 Pg, ~0.016 g m −2 yr −1 ), indicating that P is quickly recycled in the surface layers.