(full paper is archived in the Miller Library)
Title: Oxygen evolution/consumption and phototaxis in the sea anemone Anthopleura elegantissima
Student Author(s): Smith, David R.
Wright, Todd W.
Faculty Advisor(s): Wagenbach, Gary
Location: Research Reports Carleton College Biology 212
Date: November 1983
Abstract: Oxygen evolution/consumption and phototaxis in the clonal form of Anthopleura elegantissima, a sea anemone with symbiotic zooxanthellae, was investigated in order to draw comparisons between its phototaxic behavior and oxygen physiology. Anemones purged of their symbionts and placed into 125 ml erlenmeyer flasks with 115 ml of sea water demonstrated a marked decrease in the oxygen concentration of their surounding sea water regardless of their periods of exposure ot light. Anemones with symbionts, when placed in a lighted environment, showed an increase in dissolved oxygen concentration above that of their initial value. However, when placed in the dark, there was a substantial decrease in dissolved oxygen levels. Such findings would suggest that anemones with symbionts, when placed in an oxygen poor environment, would seek light so that the zooxanthellae could produce needed oxygen. Nevertheless, when anemones were placed in the dark halves of three different tanks (one oxygen-rich, one normal sea water, and one oxygen-poor), none showed a movement into the lighted halves of the tanks. A negative or neutral phototaxic response was observed, not the expected positive response. Thus it would appear that oxygen can not be implicated as a controlling factor in photosynthesis.