COASTAL AND ESTUARINE STUDIES, VOL. 59, PP. 47-73, 2004
Belowground production and decomposition along a tidal gradient in a Virginia salt marsh
Root and rhizome production and decay of Spartina alterniflora (salt marsh cord grass) and Juncus roemerianus (black needle rush) were compared at three locations along an elevation gradient over a 2-yr period using litterbags. The
elevation gradient covered a horizontal distance of nearly 500 m from the tidal creek to the upland. The three locations included
the low marsh (intermediate height-form S. alterniflora), mid marsh (short height-form S. alterniflora, Distichlis spicata, and Spartina patens) and high marsh (J. roemerianus). Additionally, organic matter accumulation at the low and high marsh locations was monitored for 5 and 4 years, respectively.
Decay of J. roemerianus roots was more rapid than decomposition of S. alterniflora roots regardless of where the materials decayed. The differences
in decay constants between J. roemerianus and S. alterniflora were not related to the differences in sediment chemistry among the three marsh zones. Root production was significantly
different between the three zones and may be related to differences in plant type, growth form, or sediment pore water chemistry.
These results suggest that sediment accretion differences in high, mid, and low marsh as a result of organic matter accumulation
are related to the ability of the plants to produce roots and to differences in the susceptibility of plant roots to decomposition.
We hypothesize that these biological processes alter marsh topography and play a critical role salt marsh transgression during
sea-level rise in sediment-limited environments.
Citation: Blum, L. K., and