The Role of Leaf Litter Nitrogen Immobilization in the Nitrogen Budget of a Swamp Stream1
- Robert G. Qualls2
The interactions of water level, dissolved nutrients, litter decomposition, and N immobilization were investigated in two blackwater stream swamps in North Carolina: Creeping Swamp (CR) and Chicod Creek (CH). Leaf litterbags were sampled along hydroperiod-elevation gradients in CR during the winter-spring high water period. Litterbags were also sampled at two elevations at two sites in CH with contrasting levels of dissolved nutrients. With the low levels of dissolved nutrients in CR, there was little difference in litter decomposition rate along elevation gradients. Decomposition was faster at the inundated sites in CH and the faster decomposition was associated with nutrient enrichment. Exogenous N immobilized in litter reached higher levels in the enriched swamp (CH). Despite faster decomposition in CH, no substantial mineralization of litter N had occurred prior to June. A budget of litter N and dissolved inorganic N inflow showed that immobilization by flooded litter over 1 linear km of Creeping Swamp during the sampling period was 87 kg, equivalent to about 25% of the inorganic N inflow. This proportion shows that litter can play a significant role in controlling N concentrations in stream water in small swamp streams.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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