HR: 1330h
AN: PP32A-0275    [PDF]
TI: Aquaculture-Based Calibration of {\it Mytilus edulis} as an Isotope Paleothermometer
AU: * Wanamaker, A D
EM: alan.wanamaker@umit.maine.edu
AF: Department of Earth Sciences, University of Maine, 5790 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: * Wanamaker, A D
EM: alan.wanamaker@umit.maine.edu
AF: Climate Change Institute, University of Maine, 303 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: Kreutz, K J
EM: Karl.Kreutz@maine.edu
AF: Department of Earth Sciences, University of Maine, 5790 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: Kreutz, K J
EM: Karl.Kreutz@maine.edu
AF: Climate Change Institute, University of Maine, 303 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: Borns, H W
EM: Borns@maine.edu
AF: Department of Earth Sciences, University of Maine, 5790 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: Borns, H W
EM: Borns@maine.edu
AF: Climate Change Institute, University of Maine, 303 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AU: Barber, B
EM: bjbarber@maine.edu
AF: School of Marine Sciences, University of Maine, 214 Libby Hall, Orono, ME 04469-5741 United States
AU: Introne, D
EM: Introne@maine.edu
AF: Climate Change Institute, University of Maine, 303 Edward T. Bryand Global Sciences Center, Orono, ME 04469-5790 United States
AB: Oxygen isotopic analysis of marine carbonate shells ($\delta^{18}$Oc) is a standard paleoceanographic method used to record the chronology of seawater temperature change. Shell $\delta^{18}$Oc is a function of seawater temperature, isotopic composition of the seawater ($\delta^{18}$Ow - related to salinity), and any species-specific fractionation that occurs during biomineralization. Previous empirical calibrations of marine bivalves used estimates of time-series variability for the key parameters in the paleotemperature equation. These estimates limited the ability to quantitatively estimate paleotemperatures and salinities from any particular species of interest or environment. The relative abundance and broad geographical distribution of the intertidal bivalve {\it Mytilus edulis} makes it an ideal species for aquaculture-based isotope paleothermometry. To calibrate {\it M. edulis}, a four by three factorial design is being used to evaluate the effects of water temperature and salinity on isotopic uptake in mussel carbonate. This experimental design consists of four circulating temperature baths (8, 12, 16, and 20 $\deg$ C), each containing three salinities (23, 28, and 33 ppt), with replicate environments for each temperature and salinity configuration. In mid-July of 2003, 4,800 juvenile mussels were collected in Salt Bay, Damariscotta, Maine, and 200 were placed in each configuration. The size (shell length) distribution of mussels, based on 100 randomly selected specimens, ranged from 9.8 mm to 20.2 mm with a mean size of 15.3 mm. This variation in shell length allows for quantification of vital effects based on age. Water samples for each configuration are being collected weekly, measured for salinity and analyzed for $\delta^{18}$Ow. Mussels are being collected monthly, prepared, and microsampled in regions of new growth for $\delta^{18}$Oc analysis. Initial results to be presented will include the time-series of $\delta^{18}$Ow, $\delta^{18}$Oc, temperature, and salinity. The calibrated paleotemperature equation developed from this study will be applied to fossil {\it M. edulis} shells collected in coastal Maine, and provide quantitative estimates of deglacial oceanographic conditions to test hypotheses that link the North Atlantic Oscillation, glacier dynamics, and climate variability ca. 15,000 - 13,000 $^{14}$C years BP.
DE: 1040 Isotopic composition/chemistry
DE: 1620 Climate dynamics (3309)
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting