Seasonal variations in radionuclide transfer in a Mediterranean grazing-land ecosystem.
We made quarterly determinations of the transfer coefficients and effective transfer coefficients for the radionuclides 137Cs, 90Sr, 40K, 226Ra, 228Ra and 228Th over a full annual cycle, in a Mediterranean grazing-land ecosystem. The input and output fluxes of the radionuclides between the different compartments of this ecosystem were quantified for the following processes: root uptake; variation in root and aerial biomass; pasture production; translocation; leaf fall; efflux due to grazing action; resuspension and subsequent aerial deposition of radionuclides. We observed there to be a marked seasonal variation for this type of ecosystem in both the transfer coefficients and the radionuclide fluxes, which impedes the soil-plant transfer being characterized on the basis of values that are constant with time.
Baeza
A
A
Dep. de Fisica. Facultad de Veterinaria, Universidad de Extremedura, Cáceres, Spain. ymiralle@unex.es
Paniagua
J
J
Rufo
M
M
Guillén
J
J
Sterling
A
A
D017753:Ecosystem; D019083:Mediterranean Region; D008685:Meteorological Concepts; D010944:Plants / Q000378:metabolism*; D011868:Radioisotopes / Q000378:metabolism*; D012621:Seasons; D012990:Soil Pollutants, Radioactive / Q000378:metabolism*
D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive