Net primary production, decomposition and export of Spartina anglica on a Suffolk salt-marsh.

An annual net primary shoot production (ANPP_s) for S. anglica of 220 and 280 g C m^-2 was recorded in 1979 and 1980 respectively. Root production was estimated at 180 and 230 g C m^-2. Shoot turnover was c2.1 yr^-1, and periods of growth and senescence overlapped to a large degree. Only 5-10% of S. anglica stems reached flowering maturity. Total stem density was maximal in late summer (>2000 m^-2 in September 1980). Live shoot biomass also reached a peak in late summer, >150 g C m^-2 in both years. Production of leaves and stems was highest at the seaward edge of the salt-marsh. A loss of dead material equivalent to 29-32% of ANPP_s per year was estimated due to microbes and micro-fauna, with an additional loss of c3% ANPP_s yr^-1 due to meiofauna. About 15-20% yr^-1 of ANPP_s was exported from the site of production as particulate matter; of this, 70% entered the estuary and the remainder was removed to the strandline.-from Authors