Nematode numbers, biomass and respiratory metabolism in a beech woodland-Wytham Woods, Oxford.

The mean annual population density of nematodes in the litter and upper 6 cm of soil was found to be 368,000 m. Mean individual live weight biomass approximated 0.2 μg and mean biomass was calculated to be 74.6 mg live weight m. No evidence of seasonal vertical migration between the litter, 0-3 cm and 3-6 cm strata was found and on average these strata contained 21.9, 46.2 and 31.9% respectively of the total number of nematodes recovered. The equivalent biomass values were 26.14, 56.57, and 17.29%. Total numbers revealed a general picture of low densities in spring and high ones in early winter, whereas biomass m was low in late summer - autumn and high in winter. The annual oxygen consumption of the extracted nematodes was calculated to approximate 0.211 m (≈4.0 kJ m) but when corrected for the effect of individual biomass (weight specific oxygen uptake) was equivalent to an energy expenditure ≈6.0 kJ m which in its turn, because of the efficiencies of extraction, probably accounts for only 87% of the total energy expenditure by the nematode fauna. The nematodes were estimated to be responsible for a minimum of 0.11% to a maximum of 0.13% of the total "soil" respiration. A production/biomass ratio of 5.16 was estimated as was a net population production efficiency of 36.63%.