As human populations continue to grow and expand, an increasingly sophisticated scientific response is needed to identify and protect natural resources. This need is seldom more evident than in the south Florida region where the growing urban Miami area encroaches on the adjoining Everglades wilderness. As ecological scientists, we are challenged to accurately understand the natural watershed-scale pattern of the Everglades flora, fauna and biogeochemistry, and how this pattern arises from the interaction of rainfall, soil, nutrients, fire, preceding history, and increasingly, human impacts. One way to study these linkages is to use natural stable isotope tracers that circulate through this large regional ecosystem. Here we request funds for an advanced isotope ratio mass spectrometer (IRMS) system to be used by ecosystems researchers at Florida International University (FIU) to investigate landscape level changes in the Miami-Everglades region. Isotope technology has been increasingly adopted by modern ecosystems research groups to follow the sources and fates of organic matter as it is produced by plants, consumed by animals and microbes, and remineralized back to inorganic constituents. The isotopes record diverse kinds of ecosystem information that range from details of photosynthesis to predator-prey interactions to emissions of trace gases such as CO2 and N20. This information often provides important checks for models based on more conventional estimates of ecosystem standing stocks and fluxes. The proposed instrumentation supports traditional measurements of C, N and S isotopes in plants, soils and animals, as well as newer innovative applications involving isotopic analyses of specific indicator compounds eluted from gas chromatographs. Six case studies illustrate the breadth of research to be supported with this instrumentation: 1. Shrimp recruitment; 2. Population analyses of freshwater fish; 3. Ecology of carnivorous Everglades bladderworts; 4. Carbon and nitrogen uptake in seagrasses; 5. Nutrient loading and N fixation in the Everglades; and 6. Organic matter fluxes in the Orinoco River and Florida Bay. The instrumentation will, along with an older PRISM mass spectrometer, form a new Isotope Facility at FIU that will be headed by Dr. Brian Fry. Dr. Fry has recently moved to FIU from MBLWoods Hole where for 9 years he led a similar laboratory that published more than 70 papers based on stable isotope results. The FIU facility will be used for research and research training by environmentally-oriented faculty and students at FIU, with yearly workshops providing a broad introduction to the use of stable isotopes as research tools. Because FIU has a student body that is 61% Hispanic or African-American and 57% female, this facility will contribute to training minorities and women, groups currently underrepresented in the sciences.
