HR: 0800h
AN: PP11A-1427    [Abstracts]
TI: Carbon Isotopic Composition of Cypress Tress from South Florida and Changing Hydrologic Conditions
AU: * Anderson, W T
EM: andersow@fiu.edu
AF: Earth Sciences Department, Florida International University, Miami, FL 33199 United States
AU: * Anderson, W T
EM: andersow@fiu.edu
AF: Southeast Environmental Research Center, Florida International University, Miami, FL 33199 United States
AU: Sternberg, L S
EM: leo@bio.miami.edu
AF: Department of Biology, University of Miami, Coral Gables, FL 33124 United States
AU: Pinzon, M C
PP11A-1427 AF: Department of Biology, University of Miami, Coral Gables, FL 33124 United States
AU: Gann-Troxler, T
PP11A-1427 AF: Southeast Environmental Research Center, Florida International University, Miami, FL 33199 United States
AU: Gann-Troxler, T
PP11A-1427 AF: Department of Biological Sciences, Florida International University, Miami, FL 33199 United States
AU: Childers, D L
PP11A-1427 AF: Southeast Environmental Research Center, Florida International University, Miami, FL 33199 United States
AU: Childers, D L
PP11A-1427 AF: Department of Biological Sciences, Florida International University, Miami, FL 33199 United States
AU: Duever, M
PP11A-1427 AF: South Florida Water Management District, 2301 McGregor Blvd., Fort Meyers, FL 33901 United States
AB: Carbon isotope values were determined from cypress tree rings from two different study areas in South Florida. One site is located in the South Eastern Everglades Marsh where pond cypress was sampled from tree islands (annual tree rings from 1970 to 2000). Bald cypress trees were sampled at the other site located along the Loxahatchee River in a coastal wetland (decadal tree rings from 1830 to 1990). The isotopic time-series from both sites display different, location-specific information. The pond cypress isotopic time-series has a positive correlation with the total amount of annual precipitation, while the bald cypress data from Loxahatchee River study area had two different records dependent on the level of saltwater stress. Typically terrestrial trees growing in a temperate environment, water stress causes an increase in water-use-efficiency resulting in a relative ¹³C enrichment. However, trees growing in wetland settings in some cases do not respond in the same manner. We propose a conceptual model on changes in carbon assimilation and isotopic fractionation as controlled by differences in stomatal resistance (water stress) and mesophyll resistance (biochemical and nutrient related) to explain the isotopic records from both sites. With further work and longer time-series, our approach may be tested, and used to reconstruct change in hydroperiods further back in time.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1705 Biogeosciences
DE: 4870 Stable isotopes (0454, 1041)
DE: 4914 Continental climate records
DE: 4920 Dendrochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005