ORGANICALLY-BOUND FERROUS IRON (ORG-FE(II)) AS AN INDICATOR OF ECOSYSTEM HEALTH - A COMPARISON OF SUBURBANIZED AND FORESTED STREAMS IN THE SOUTHEASTERN US

Iron is one of the essential micronutrients for phytoplankton growth. However, most iron in a flowing surface stream is oxidized to form fer ric hydroxide (Fe(OH)(3)) which phytoplankton cannot assimilate. Disso lved organic Matter (DOM) in streams act as a ''vehicle'' to complex w ith ferrous iron (Fe(II)) and maintain it in a Fe(II) state until it r eaches the estuary, where it can be utilized by phytoplankton. Residen tial development represented by the Dog Creek watershed exhibits typic al trend in coastal zones throughout the southeastern US. Development is generally characterized by increasing impervious areas of the water shed, which decreases the infiltration of water and increases surface runoff and pollutants. The reduction of org.- Fe(II) observed in the s uburbanized stream suggests that runoff from the suburbanized watershe d, has less association with organic-rich soils (i.e., humate). Since org.- Fe(II) is a positive parameter of the southeastern US stream wat er quality supporting primary productivity in coastal zone, its concen tration could be used to represent an indicator of ecosystem health.