ON THE RATE OF OXYGEN CONSUMPTION BY FERTILIZED AND UNFERTILIZED EGGS : II. CUMINGIA TELLINOIDES

Area of Science:

• Marine Biology
• Developmental Biology
• Invertebrate Physiology

Background:

• Fertilization triggers significant physiological changes in eggs.
• Oxygen consumption is a key indicator of metabolic activity.
• Previous studies noted decreased oxygen consumption in fertilized annelid eggs.

Purpose of the Study:

• To quantify oxygen consumption rates in Cumingia clam eggs before and after fertilization.
• To compare the metabolic response of Cumingia eggs to that of annelid eggs.

Main Methods:

• Measurement of oxygen consumption using respirometry.
• Comparison of oxygen consumption rates in unfertilized and fertilized Cumingia eggs.

Main Results:

• Unfertilized Cumingia eggs consumed approximately 3.1 mm³ O₂ per hour per 10 mm³ egg volume.
• Fertilized Cumingia eggs showed a reduced consumption rate of 1.4 mm³ O₂ per hour per 10 mm³ egg volume.
• This represents a decrease to about 45% of the pre-fertilization oxygen consumption rate.

Conclusions:

• Fertilization leads to a substantial decrease in oxygen consumption in Cumingia clam eggs.
• The observed metabolic downregulation is similar to that seen in the annelid Chaetopterus, suggesting conserved physiological responses.
• This finding contributes to understanding early developmental metabolic shifts in marine invertebrates.