Patterns in belowground primary productivity and belowground biomass in marshes of the Everglades' oligohaline ecotone

This study quantified and assessed patterns in belowground primary productivity (BPP) and belowground biomass in Cladium jamaicense marshes of the oligohaline ecotone, a transition zone between the two dominant ecosystems (freshwater marsh and mangrove forest) in the Everglades. A 2x2x2 factorial design was used with transect (Shark River Slough/Taylor Slough), site (estuarine/freshwater), and season (dry/wet) as factors. BPP and belowground biomass were measured using root ingrowth and soil cores, respectively. Across all sites, BPP was significantly greater in the dry season. BPP peaked in Taylor Slough from April-July, the decrease likely due to oxygen saturation in the soil during marsh dry-down. BPP stayed constant in Shark River Slough, which remained inundated almost year-round. These results indicate that Everglades restoration efforts may negatively impact C. jamaicense marshes. Belowground biomass increased with nutrient availability, though the effects of hydroperiod were unclear. Future research should include root decomposition and mortality as they are crucial to understanding belowground processes in Everglades marshes.