Appendix E. Percentage 15N derived from labeled Spartina detritus in experiments conducted in hybrid-Spartina invaded and tidal flat sediments. Surface = detritus placement in upper few millimeters of sediment. Subsurface = detritus placement in litter bags 2 cm below the surface. Exposure periods differ for surface and subsurface treatments. c/o = carnivore/omnivore; ssdf = subsurface-deposit feeder; sdf = surface deposit feeder.