EFFECTS OF SALINITY AND NUTRIENTS ON MONO- AND DIAXENIC CULTURES OF TWO STRAINS OF ARTEMIA SALINA

¹ St. John's University, Biology Dept., Jamaica, New York 11432
² Haskins Laboratories, 305 E. 43rd Street, New York, N. Y. 10017

1. Two tetraploid strains of Artemia salina were axenized. The bisexual strain from the Great Salt Lake was obtained bacteria-free by serial washes of the wintering eggs in Merthiolate. The parthenogenetic strain from the Comacchio salines was axenized by serial washes of gravid females and nauplii in antibiotics; the yeast infection was eliminated by high salinity.

2. Methods for the maintenance of the bacteria-free stocks were defined. Various phytoflagellates were found suitable food organisms for both strains of Artemia when grown in appropriately enriched sea water.

3. Two species of Dunaliella were adapted to grow in synthetic salt solutions ranging from 0.5 to 20.5% total salts. These conditions permitted the study of the effect of salinity on egg production of Artemia in diaxenic culture.

4. Great Salt Lake Artemia grown at various salinities, in inorganic enrichments and fed ad libitum with salinity-adapted D. viridis and D. salina, failed to deposit eggs in solutions containing less than 3% salts. The Comacchio Artemia was even more sensitive: in low salinities development was inhibited even though the algae were abundant.

5. The reduced fecundity of Artemia at low salinities could be reversed by adding organic enrichments, i.e., small quantities of glucose, liver extract, yeast extract and vitamins. The organic enrichment was thought to affect the metabolism of the algae rather than that of Artemia.