BODY FLUID COMPOSITION AND AERIAL OXYGEN CONSUMPTION IN THE FRESHWATER MUSSEL, <i>LIGUMIA SUBROSTRATA</i> (SAY): EFFECTS OF DEHYDRATION AND ANOXIC STRESS

Abstract

1. Ligumia subrostrata, removed from water will survive >40 days if dehydration is minimized by high relative humidity. They are not anoxic but consume oxygen from the air (Qo2 59 µl O2/g dry tissue-hr). One source of energy is from the large glycogen stores (36% of dry tissue).2. Animals removed from water and exposed to either low relative humidity (45-55%) or N2 atmosphere will survive about 5-7days. The maximum total solute in the body fluids of surviving animals is 160-180 mOsmoles.3. Sodium, Cl, K, and Ca account for 72% of the total solute in the body fluids of fresh water acclimated animals. Dehydration increases the concentration of Na proportional to the amount of water lost. There is a significant shift of Cl from the tissues into the body fluids during dehydration.4. When the animals are out of water, forced anoxia increases the body fluid total solute but the Na and Cl contribution is small. The major ions in the body fluids are calcium and bicarbonate or succinate; reflecting a build up of metabolic acids. Lactate concentration in the body fluids is low. These animals experience a significant oxygen debt since oxygen consumption is elevated when returned to air (Qo2249 µl O2/g dry tissue-hr).5. Mussels are facultative anaerobes and will survive for extended periods of time in N2 gassed water (< 54 µl O21). The body fluids are slightly changed from normal suggesting the metabolic products are excreted. These animals do not suffer an oxygen debt.