Static and dynamic aspects of nitrogen cycling in the salt marsh graminoid Spartina alterniflora [Georgia]

Processes of nitrogen cycling including root uptake, translocation, leaching, detrital incorporation, and overwinter storage were determined for a medium-height form of Spartina alterniflora in Georgia, USA. Mean concentration of total N in live above-and belowground plant tissues was 0.60% of dry mass. Aboveground concentrations (1.05%) were more than twice the belowground N concentrations. The seasonal patterns of nitrogen concentrations were similar for aerial and subaerial Spartina tissues with maxima observed between December and May. Concentrations were highest in short, young stems and decreased as plants matured, senesced, and died. Seasonal patterns of nitrogen accumulation were out of phase for aerial and subaerial tissues. Maximum accumulation was in midsummer for aboveground plant parts and in late winter for belowground tissue. During winter @