ROLE OF OXYGEN IN AFFECTING SURVIVAL AND ACTIVITY OF PELODERA-PUNCTATA (RHABDITIDAE) FROM SEWAGE SLUDGE

The effect of O2 on the survival and activity of P. punctata was investigated. P. punctata was maintained in monoxenic cultures in which Pseudomonas fluorescens was the bacterial food source. When nematodes were kept for 2 wk under a reducing and anaerobic atmosphere 28-40% of the cultures survived. The effect of P[partial pressure]O2 and PCO2 on activity was determined by sealing the cultures and subsequently monitoring the activity and gas concentrations using gas chromatography. A PO2 of > 7000 dyne cm-2 (5 mm Hg) was necessary to sustain activity while PCO2 showed no effect at the concentrations observed. These findings were discussed with regard to role of rhabditid nematodes in sewage sludge which is often O2 deficient.