Porewater chemistry associated withPhragmites andSpartina in a Connecticut tidal marsh

Abstract

Porewater chemistry and plant height were examined along 5 short transects extending from sections of tidal marsh dominated by the common reedPhragmites australis to those dominated bySpartina alterniflora. Phragmites was found at relatively higher tidal elevations along 4 of 5 transects; along all transects,Phragmites was growing and flowering throughout a porewater salinity range from 12 to 30 ppt. Dissolved inorganic phosphorus concentrations varied from 0 to >35 μM in bothSpartina andPhragmites sections of marsh, but ammonium concentrations averaged >40 μM in zones dominated bySpartina and 400 μM, perhaps due to sulfide inhibition of nitrogen uptake for growth. The persistence ofPhragmites at field conditions of high salinity and elevated sulfide concentrations suggests that hydrologic management may be insufficient to eradicatePhragmites in tidal wetlands.