INTRODUCTION During the weapons testing program of Operation Castle at Bikini and Eniwetok Atolls in the spring of 1954, the Applied Fisheries Laboratory of the University of Washington carried out studies on the uptake of radioactive materials in a variety of aquatic and terrestrial plants and animals. In addition to the programmatic studies, exploratory studies also were continued, including a study of the reef algae. Collections of algae from near the Marine Biological Laboratory on Parry Island, alga Eniwetok Atoll, indicate that a small red (Asparagopsis) has a remarkable affinity for iodine as measured by the uptake of I 131 immediately following weapon detonations at the Pacific Proving Ground. COLLECTION OF MATERIAL Immediately following the March 1, Bikini Atoll, 1954 experiment at it was observed that the background level of radioactivity on the reef of the seaward side of Parry Island had increased. Most of the algae growing on this reef had only Slightly higher readings than the background level. the level for Asparagopsis taxiformis (Delile) However, Collins and Hervey, a delicate, branching red alga, was unexpectedly high. SOF ARCBIVE

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