Spartina altemiflora root dynamics in a Virginia marsh

A l~tter bag technique was used to measure root and r h ~z o m e decomposition and production for 2 years In creekside and intenor sediments In a Sparbna alterniflora marsh on the seaside of the Delmarva Peninsula, Virginia, USA Decay was equally rapid regardless of incubat~on in either creeks ~d e or ~n t e r ~o r sedlrnents and dld not vary with depth Weight loss d u n n g the f~rst growing season was 39 and 35 % (creekslde and interlor respectively) By the end of the second growing season between 81 and 88% (creekside and intenor respectivelyj of the starting root and rhizome material had decayed In creekside sed~ments, very llttle root growth was measured during e ~t h e r year and root production was highly vanable between years (1253 and 99 g m 2, In the intenor marsh, the patterns of root growth and the amount of root matenal produced were similar each year (2016 and 2269 g m-') Root and rhizome turnover was faster in the creekside sedunents (2 63 yr ') than in the marsh lntenor (0 54 yr '1 The greater root production and slower root turnover in the ~n t e n o r marsh occurred in sediments with elevated salinities and oxidation-reduction potent~als, and lower sediment saturation These results suggest that differences in organlc matter accumulation In h ~g h and low marsh areas may be explained by differences In root production and not differences In decay processes