HR: 16:30h
AN: U52C-03    [PDF]
TI: Mathematical simulation of the diel O, S, and C biogeochemistry of a hypersaline microbial mat
AU: Decker, K
EM: kdecker@uvm.edu
AF: California State University Monterey Bay, Earth System Science and Policy, Seaside, CA 93955 United States
AU: Decker, K
EM: kdecker@uvm.edu
AF: NASA Ames Research Center, Ecosystem Science, Moffett Field, CA 94035 United States
AU: * Potter, C
EM: cpotter@mail.arc.nasa.gov
AF: NASA Ames Research Center, Ecosystem Science, Moffett Field, CA 94035 United States
AB: The creation of a mathematical simulation model of photosynthetic microbial mats is an important step in our understanding of key biogeochemical cycles that may have altered the atmospheres of early Earth and of other terrestrial planets. A modeling investigation is presented here as a tool to utilize and integrate empirical results from research on hypersaline mats from Baja California, Mexico into a computational system that can be used to simulate biospheric inputs of trace gases to the atmosphere. An early version of our model calculates fluxes and cycling of oxygen, sulfide, and dissolved inorganic carbon (DIC) via abiotic components and via the major bacterial guilds: cyanobacteria (CYA), sulfur reducing bacteria (SRB), purple sulfur bacteria (PSB) and colorless sulfur bacteria (CSB). We used generalized monod-type equations that incorporate substrate and energy limits upon maximum rates of metabolic processes such as photosynthesis and sulfate reduction. We ran a simulation using temperature and irradiance inputs from data collected from a microbial mat in Guerrero Negro in Baja Mexico. Model oxygen, sulfide, and DIC results compared well with data collected in the field mats. A divergence from the field data was an initial large negative DIC flux early in the morning and little flux into the mat thereafter in the simulation. We hypothesize that this divergence will be reduced or eliminated if the salinity of the water surrounding the mat were used as an environmental input and as a limit to photosynthesis rates. Salinity levels, organic carbon, methane, methanogens and green nonsulfur bacteria will be added to this model before it is incorporated into a global model to simulate geological time scales.
UR: http://geo.arc.nasa.gov/sge/casa/
DE: 1610 Atmosphere (0315, 0325)
DE: 1615 Biogeochemical processes (4805)
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
DE: 1640 Remote sensing
SC: U
MN: 2003 Fall Meeting