Nutrient Limitation of Plants and Soil Microbial Growth in an Arctic Coastal Salt Marsh.

In order to assess the nutrient limitation of plants and soil microorganisms in the Arctic coastal salt marsh at La Pérouse Bay, Manitoba, a nitrogen (N) and phosphorus (P) fertilization experiment was conducted. The partitioning of carbon (C), N and P was measured from June 2003 to July 2004. Soil solution inorganic N and P results indicate that the system is strongly limited by N and, to a lesser extent by P. Results indicate that strong N-limitation and high concentrations of inorganic P compared to dissolved organic P moderate the release of phosphatases. Primary productivity is co-limited by N and P, while soil microbial biomass is limited by carbon. Plants and microbes compete for N, but not P, during the summer. Overall, there was a seasonal shift in the allocation of nutrients within the community, from a microbial dominated system in the winter to a plant-dominated system in the summer.