Fig. 2 Terrestrial C loss rates from stream reaches increased with N and P concentrations.

Fig. 1 Terrestrial C residence time was approximately halved with experimental nutrient enrichment. Increased nutrient inputs (+) reduced terrestrial particulate C residence time (–) and increased export of fine detrital particles (+) and respiration rates [which increased on C substrates (11) but decreased at reach scales; +/−]. Inset graph: Reach-scale leaf litter loss rates were faster in enriched (dashed lines) than in reference (solid lines) streams; the inverse of these rates is residence time. Colors correspond to the same years in (A) (reference versus enriched streams; N+P experiment; n = 12 annual rates) and to the same streams in (B) (pretreatment versus enriched years; N×P experiment; n = 15 annual rates). Data shown for litter loss are untransformed but were natural log–transformed for analyses and the calculation of loss rates (k, per day). The larger image depicts terrestrial organic C inputs, which enter as leaf litter, wood, and dissolved organic carbon (DOC), and outputs as hydrologic export (fine and coarse particles, DOC) and respired CO2 in deciduous forest streams, using an image of one of the N×P experimental stream sites.