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 ferric hydroxide (Fe(OH)(3)) which phytoplankton cannot assimilate. Dissolved organic Matter (DOM) in streams act as a ''vehicle'' to complex with ferrous iron (Fe(II)) and maintain it in a Fe(II) state until it reaches the estuary, where it can be utilized by phytoplankton. Residential development represented by the Dog Creek watershed exhibits typical trend in coastal zones throughout the southeastern US. Development is generally characterized by increasing impervious areas of the watershed, which decreases the infiltration of water and increases surface runoff and pollutants. The reduction of org.- Fe(II) observed in the suburbanized stream suggests that runoff from the suburbanized watershed, has less association with organic-rich soils (i.e., humate). Since org.- Fe(II) is a positive parameter of the southeastern US stream water quality supporting primary productivity in coastal zone, its concentration could be used to represent an indicator of ecosystem health.