Walt Dineen Society Annual Conference '97
|Session VII: Marine Ecology
||Abstract #: 97707
SALINITY AND ORGANIC MATTER TRANSFORMATIONS AS CONTROLS ON WETLAND-WATER COLUMN INTERACTIONS IN A SOUTH FLORIDA MANGROVE
Stephen Davis and Daniel Childers
Department of Biological Sciences, Florida International University, University Park, Miami, FL 33199
In August and November 1996, we quantified wetland-water column fluxes and processes in dwarf and fringe mangroves of Everglades National Park. We hypothesized that key organic matter transformations are maximal at 0-5 ppt, and that movement of this zone controls nutrient availability and flux. We used dwarf mangrove enclosures, in-channel mangrove flumes, prop root enclosures, and serial filtration experiments to [hierarchically] test our hypothesis. Island enclosures showed significant uptake of NH4 (15.3 - 31.2 µM/m2/hr) and significant release of NN (46.4 µM/m2/hr) and TP (4.4 µM/m2/hr). SRP fluxes varied. Flume data showed a relationship between salinity and nutrient dynamics, particularly with P exchange. Red mangrove prop roots tended to take up NH4and SRP while releasing NN and TP; NH4 and NN fluxes were always greater when prop roots contained epibiont communities. We performed serial filtrations on water incubated for 2 days in the root bag enclosures; this suggested a conversion of organic P to SRP in the presence of red mangrove prop roots (with and without epibionts). Data from January 1997, which also included a time-series serial filtration experiment where fresh and saline waters were mixed to different salinites, will allow us to more fully address our hypothesis.