Metabolic Activity of the Epiphytic Community Associated with Spartina alterniflora

Primary production and respiration rates were determined for two epiphytic communities associated with Spartina alterniflora Loisel., in the southwestern Barataria Bay area of Louisiana. The communities studied were: (1) a shoreline community and (2) a community 1.5 meters inland from the shoreline site. Annual mean net production and respiration rates for the shoreline community were 25.8 and -19.6 mg C(m super(2) substrate area)h respectively; whereas the inland community showed corresponding rates of -3.3 and -12.5 mg C(m super(2) substrate area)h, respectively. Thus, the shoreline community was a net contributor to system production; the inland community was an energy sink. The inland community was elevated 15 to 20 cm above the shoreline community, lacked the conspicuous filamentous algal growth common at the shoreline location, and had a significantly smaller diatom population. The role of epiphytes is speculated to be one of quality rather than quantity production. (DBO)