Fry, B. Coastal Ecology Institute, LSU, bfry@lsu.edu
Bern, A. Clear Lake Environmental Research Center, albern@ucdavis.edu
Ross, M. S.. Southeast Environmental Research Program, rossm@servax.fiu.edu
Meeder, J. F.. Southeast Environmental Research Program, meederj@servax.fiu.edu

 
STABLE ISOTOPE STUDIES OF NITROGEN USE BY THE RED MANGROVE, RHIZOPHORA MANGLE L., IN SOUTH FLORIDA
 
To help define N sources and patterns of N processing in mangrove ecosystems, we assayed mangrove leaf nitrogen contents and delta 15-N values in three marshes along the south Florida coast. In each marsh, samples were collected from dwarf mangroves at interior locations and taller mangroves at the ocean fringe. Highest mangrove delta 15-N values (up to 13 o/oo) occurred along the western margin of Biscayne Bay and were associated with high-nitrate waters from local canal discharges, indicating that delta 15-N surveys can help identify areas of coastal N pollution. Highest leaf nitrogen contents (2% N) were also observed at this site in fringe mangroves. Lower delta 15-N values (to -5 o/oo) and leaf nitrogen contents (to 0.9%) occurred in more pristine mangrove marshes of the Florida Keys. Lower values likely reflect less anthropogenic N entering the marshes, as well as differences in plant physiology that occur along the fringe-dwarf gradient.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS32TU1514S