Physiographic control on the development of Spartina marshes.

The established paradigm indicates that low-lying marsh production is primarily regulated by submergence and the resulting edaphic conditions. The physical sedimentary environment is in turn deemed to affect production through its effect on marsh-surface elevation relative to sea level. However, our results working with Spartina anglica indicate that production and marsh perennation are controlled by variation in surface level relative to the plant's meristematic base and not hindered by prolonged submergence. These findings suggest that plant responses to changes in sedimentary conditions determine marsh development and survival in the short term, independently of long-term changes in relative sea level.