Effects of Temperature, Rainfall, and Fauna on Transfer of ^(137)CS, K, MG, and Mass in Consumer‐Decomposer Microcosms

Microcosms containing leaf litter, sand, and three, six, or nine millipedes were incubated for 14 weeks at either 5°, 15°, or 25°C under three rates of simulated rainfall. Effects of temperature, rate of leaching, and millipede density on transfer of (137)Cs, K, Mg, and mass and on evolution of CO2 were analyzed statistically and by analog computer simulation. Loss rates from litter increased in the order: Mg < mass <(137)Cs 2; (137)Cs to sand; and K to leachate. Loss rates of Mg and mass evolution of CO2, and transfers of (137)Cs were all influenced primarily by temperature and secondarily by millipede density. Only K was affected more by leaching than by millipedes. Production of CO2 showed a Q10 ° 2, but mineral transfer did not double at each 10°C increase because of significant temperature—moisture interaction. Computer simulation showed that pathways and rate coefficients for transfer of (137)Cs were identical whether it originated from litter or soil, that the major pathways were from litter to soil and from litter via millipedes to soil, and that about 7% of the initial leaf (137)Cs was easily leached from litter and transferred to soil and leachate during the first month. At higher temperatures, drying and rewetting cycles of the litter appeared to shift the litter—to—soil transfer of (137)Cs from the millipede ingestion—excretion pathway to that effected by microbial immobilization—mineralizaton cycles.