The Effect of Environmental Factors on the Respiration of Tubife

Abstract

A study has been made to determine the effect of various environmental factors upon the metabolic responses of the oligochaete, Tubifex tubifex. The metabolic responses were measured as the mean rate of oxygen consumed per individual. It was found that: different size populations consumed varying quantities of oxygen per individual. An alkaline (7.5) to an acid (6.1) shift in pH produced no difference in the oxygen consumption rate in comparison with the control group. The oxygen consumption rate at zero degrees centigrade was significantly lower than in any other treatment group. There was also a lowering of activity level at this temperature. Nonlethal concentrations of 1 ppm of copper sulfate and of sodium pentachlorophenate produced significantly higher oxygen consumption rates. Phenol produced the higher rate. There was an accompanying increase in activity level. A 1 ppm concentration of zinc sulfate produced no increase in activity or in oxygen consumption from that of the control group. Differences in oxygen consumption rates in the experimental environments suggest altered cellular metabolism as the result of adaptive changes. INTRODUCTION Several investigators (Alsterberg, 1922; Brazda and Rice, 1940; Collier, 1947) have studied the physiology of the fresh water oligochaete, Tubifex tubifex. Recent physiological investigations have been extensively reviewed by Prosser and Brown (1961). Tubifex tubifex is of interest to biologists because it is found in grossly polluted areas where the oxygen content is at such a low level that most metazoans are not able to survive. However, the effect of various environmental factors, upon the oxygen consumption of the worms has no,t been thoroughly investigated. Except for the presence, of the subintestinal plexus, similar to the supraintestinal plexus, the respiratory apparatus of Tubifex tubifex shows no unusual features. It consists of the body and intestinal walls together with the accompanying network of blood vessels. The respiratory adaptations of Tubifex may be summarized as follows: (1) They are aerobic organisms requiring only a low, actively utilizable, minimum of oxygen. (2) Hemoglobin is present in the blood and is used when needed. (3) They are oxygen dependent organisms that appear able to adjust their metabolism to the available oxygen. (4) In reduced environmental oxygen they are metabolic regulators that regulate their oxygen consumption down to some critical pressure, below which their oxygen consumption declines rapidly (Prosser and Brown, 1961). The worms characteristically have a distinctive body movement 1 Present address: Department of Biology, Western Michigan University,