Nitrogen and phosphorus cycling in an ombrotrophic peatland: A benchmark for assessing change
Citation:
Salmon, V., D. Brice, S. Bridgham, J. Childs, J. Graham, N. Griffiths, K. Hofmockel, C. Iversen, T. Jicha, R. Kolka, J. Kostka, A. Malhotra, R. Norby, J. Phillips, D. Ricciuto, C. Schadt, S. Sebestyen, X. Shi, A. Walker, J. Warren, D. Weston, X. Yang, AND P. Hanson. Nitrogen and phosphorus cycling in an ombrotrophic peatland: A benchmark for assessing change. PLANT AND SOIL. Springer, New York, NY, , 649-674, (2021). https://doi.org/10.1007/s11104-021-05065-x
Impact/Purpose:
The large pool of soil C stored in northern peatlands has accumulated over millennia because production has surpassed decomposition under the cold, wet, and acidic conditions found in these ecosystems. Slow decomposition and isolation from groundwater sources also mean that ombrotrophic peatlands have low availability of nitrogen (N) and phosphorus (P). To better understand the importance of these two limiting nutrients, we used field observations to build N and P budgets for a forested bog in northern Minnesota. Our results showed that annual inputs of P to this ecosystem were balanced by annual losses but N was accumulating in the ecosystem at 0.2 ± 0.1 g N m-2 y-1. Stoichiometry of whole-plant biomass revealed plant functional types differed in N versus P limitation, with trees exhibiting a stronger N limitation than shrubs or Sphagnum moss. High biomass and productivity of Sphagnum meant that the moss layer stored and cycled a large proportion of plant N and P. Comparisons between our empirically-derived nutrient budgets and modern-day, site-level simulations from the peatland version of the Energy Exascale Earth System Model (ELM-SPRUCE) demonstrated the model captured N cycling within the dominant plant functional types well. Our N and P budgets serve as a baseline for quantifying the nutrient cycling response of peatland ecosystems to both real and simulated climate change. Combining field observations and model simulations improves our understanding N and P dynamics within nutrient-limited northern peatlands and represents a crucial step toward improving C cycle projections into the 21st century.
Description:
This work will provide a baseline for nutrient cycling and budgets in the SPRUCE bog in which all future studies can be compared to.
URLs/Downloads:
DOI: Nitrogen and phosphorus cycling in an ombrotrophic peatland: A benchmark for assessing change
SALMONETAL_2021PLANT&SOIL.PDF (PDF, NA pp, 1535.627 KB, about PDF)