THE RED TIDE — SMITH 375 



fish and the sore throats, quite forgetting that red tide, dead fish, and 

 sore throats had appeared off the Florida coast long before any war 

 gas was available for dumping. Some theories were even more fan- 

 tastic, involving the deadly and secret activities of foreign agents. 



But the investigators by now were satisfied as to the immediate 

 cause of the trouble. Small fishes were placed in samples of water 

 containing "Jim Brevis." The fishes died in less than 24 hours. In 

 similar tanks of water with no "Jim Brevis" the fishes lived. Samples 

 of sea water from a red-tide outbreak were heated nearly to boiling 

 point and the vapor given off was found to cause coughing and sneezing. 



Unfavorable publicity in the wake of the red-tide troubles led to a 

 vigorous effort to combat them, and the scientists from Miami who 

 conducted the original investigation were now reinforced by investi- 

 gators from the United States Fish and Wildlife Service and the 

 Woods Hole Oceanographic Institution. Dr. Paul S. Galtsoff con- 

 firmed the original findings of the poisonous nature of "Jim Brevis" 

 by carefully conducted tests. Irritant gas, first earlier obtained by 

 boiling red-tide water, was traced by Alfred Woodcock to small par- 

 ticles of water thrown into the air by breaking waves, and remaining 

 in suspension for a considerable time. In this way the red-tide poison 

 became airborne. Injection of a small amount of red- tide water by 

 spray into the nose caused the familiar sneezing and sore throat, thus 

 confirming Woodcock's theory. 



THE CAUSE OF A CAUSE 



The direct cause of red tide and its attendant evils was clear enough. 

 The recognition of "Jim Brevis" did not help very greatly in prevent- 

 ing it though. It is true that copper sulfate and other chemicals have 

 long been known as potential killers of plankton blooms if sprayed 

 on the sea, but, by the time a red-tide outbreak is noticed, the fishes 

 are dead and drifting onto the beaches and the tourists and residents 

 are coughing and sneezing. It is then too late. Like an explosion, the 

 red tide must be stopped before it breaks out. It is necessary to predict 

 the time and place of an outbreak. The $64 question was what are the 

 events or causes which antedate the sudden catastrophic blooming of 

 "Jim Brevis"? 



An obvious thing to look for is the source of food to support the 

 rapid growth of plankton characteristic of plankton blooms. In 

 Florida there seemed to be a ready answer in the existence of phos- 

 phate mining operations. Land plants need fertilizer — phosphorus, 

 nitrogen, potassium — for food, and also certain other substances in 

 very small quantities to promote and sustain growth. This is equally 

 true even of small plantlike cells in the sea, including "Jim Brevis." 

 Moreover it frequently happens that the phosphorus compounds are 



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