COMPARATIVE-ASSESSMENT OF THE AEROBIC AND ANAEROBIC MICROFLORAS OF EARTHWORM GUTS AND FOREST SOILS

Aerobic and anaerobic microbial potentials of guts from earthworms (Lu mbricus iEus rubellus Hoffmeister and Octolasium lacteum (Oerl.)) coll ected from a beech forest were evaluated. On the basis of enumeration studies, microbes capable of growth under both aerobic and anaerobic c onditions were more numerous in the earth-worm intestine than in the b eech forest soil from which the worms were obtained. The intestine of worms displayed nearly equivalent aerobic and anaerobic microbial grow th potentials; in comparison, soils displayed greater aerobic than an aerobic microbial growth potentials. Hence, the ratio of microbes capa ble of growth under obligately anaerobic conditions to those capable o f growth under aerobic conditions was higher with the worm intestine t han with the soil. Process Level studies corroborated these population differentials: (i) under anaerobic conditions, worm gut homogenates c onsumed glucose, cellobiose, or ferulate more readily than did soil ho mogenates; and (ii) under aerobic conditions, worm gut homogenates con sumed cellobiose or oxygen more readily than did soil homogenates. Col lectively, these results reinforce the general concept that the earthw orm gut is not microbiologically equivalent to soil and also suggest t hat the earthworm gut might constitute a microhabitat enriched in micr obes capable of anaerobic growth and activity.