A major concern for the State of Florida is the impact of the Deepwater Horizon oil spill on coral-reef and other hardbottom communities of the Florida shelves. We propose to test both the toxicity and the sublethal effects of crude oil and dispersants on organisms that are amenable to experimental manipulation and representative of the reef community. Test organisms are reef-dwelling benthic foraminifer Amphistegina gibbosa and Archaias angulatus. These taxa host symbiotic algae, calcify and are abundant along most of the Florida coastline. These foraminifera are already in use as bioindicators for reef health. Toxicity tests of aged crude oil, dispersant, and mixed oil and dispersant concentrations in seawater will be reported. Parameters to be reported include Lethal Concentration to 50% of test populations (LC-50), as well as Effects-Range Medium Concentration (affecting 50% of test specimens), Effects-Range Low Concentration (affecting 10% of test specimens), and No Observed Effect Concentration (NOEC) based on incidences of mortality, growth rates in culture, susceptibility to bleaching, and asexual reproduction parameters. Two USF graduate students will participate in the research. Our research will be carried out in cooperation with Drs. Kim Ritchie and Dana Wetzel of Mote Marine Laboratory, who are assessing the effects of oil and dispersants on coral (Porites) larvae.