Nitrogen dynamics in floating and non-floating peatlands in the Western Boreal Plain

Abstract

. 2008. Nitrogen dynamics in floating and non-floating peatlands in the Western Boreal Plain. Can. J. Soil Sci. 88: 697Á708. The overall objective of this study was to measure the major nitrogen pools and fluxes in nutrient-and peat-rich, vegetated marshes and fens surrounding shallow ponds in the Western Boreal Plain (WBP) of Canada. Within the same peatland-pond complex, marshes and fens did not differ from each other in major N fluxes and pool sizes; however, significant differences in N dynamics were measured between different peatland-ponds. Specifically, N cycling rates (gross and net mineralization) were much greater in a floating peatland than in a non-floating peatland. Gross N mineralization rates were 59 and 453 mg N m (2 d (1 in the non-floating and floating peatlands, respectively. Gross ammonification rates were approximately 4Á10 times net rates while gross nitrification rates were 500Á800 times net rates, indicating rapid turnover of extractable inorganic N pools. Increased moisture and carbon in the floating peat supported higher microbial biomass and activity, however net primary production values were lower, presumably due to competition by microbes for available inorganic N. Monthly measurements of N fluxes were combined to provide an estimate of annual internal N cycling within marshes and fens surrounding shallow ponds in the WBP.

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

“…Among the lines of evidence, we know that the size of riparian forests tends to increase from upstream to downstream sections due to topographic constraints, potentially increasing primary production and associated nitrogen uptake and carbon production along the river continuum. This idea is supported by general patterns of increasing mineralization along the stream network associated with a shift toward fine-textured Lupon et al (2016), Van Cleve et al (1993), and Wray and Bayley (2008). soils (Evans and Schoenholtz, 2011;Noe et al, 2013).…”

Soil organic matter content controls gross nitrogen dynamics and N2O production in riparian and upland boreal soil

“…In the riparian soil at sites 1 and 8, the observed gross mineralization (14.8 and 4.7 µg N g −1 SDW day −1 , respectively) and nitrification (0.7 and 1.9 µg N g −1 SDW day −1 , respectively) compare in magnitude to those from other studies. For peatlands in boreal and cold climates, gross mineralization of 1.1–16.2 µg N g −1 SDW day −1 and gross nitrification of 1.2 µg N g −1 SDW day −1 have been reported (Wray & Bayley, ; Marushchak et al ., ). For the upland forest soil, gross N mineralization was close to rates reported for Podzols in the UK (Cookson et al ., ).…”

Nutrient supply patterns across the Sandhill Fen reclamation watershed and regional reference fens in Alberta, Canada: An ion exchange membrane study

“…Boreal peatlands generally are perceived to be nitrogen‐limited ecosystems because cool peat temperatures, water‐saturated conditions, and poor litter quality inhibit turnover (Aerts, Wallen, & Malmer, ; Bayley, Thormann, & Szumigalski, ; Damman, ; Hartsock et al, ; Humphrey & Pluth, ; Regina, Nykanen, Silvola, & Martikainen, ). Further, in combination with efficient nutrient uptake by both plants and microbes (Stuart, Wieder, & Vile, ), removal of reactive nitrogen species via denitrification pathways also depletes nitrogen pools (Wray & Bayley, ). In our study, ammonium and nitrate contents adsorbed to PRS probes were quite low across all sites.…”