44 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



other i^roducts secreted by them and released in great quantities through the 

 rapid decay of the organisms, as is often the case in an outbreak of "red water" 

 along the California coast, proves oA'crwhelming to those animals which are 

 not able to escape from the infested area (Kofoid, 1911). These animals, which 

 include such forms as the holothurians, sipunculids, mollusks, the sting ray 

 (Urolophus halleri) and guitar fish (Rln'nolxitis productis) , die in great num- 

 bers and are cast up by the tide upon the beaches. 



In the more common occurrences of small patches of red or yellow water 

 which may persist on the surface of the ocean for a few days and then disap- 

 pear as mysteriously as they came are to be found evidences of the great plas- 

 ticity of these organisms, and their physiological reactions to slight changes in 

 the chemical content of the oceanic waters. These reactions and interrelations 

 are obscure, and but little can be done besides pointing out a few of the lines 

 along which further evidence must be looked for. 



"Red Water." — The occurrence of isolated patches of discolored water at 

 the surface of the ocean is frequently oliserved during the summer months 

 along the shores of southern California. These areas vary in color from a 

 slight greyish turl^idity of the water to a decided yellow, red or dark brown 

 color. The extent of the water thus affected may be limited to a few hundred 

 yards, such as occurred during July, 1914, at La Jolla, and in July and August, 

 1917, from Long Beach to Santa Barbara, California, or it may extend for a 

 hundred miles or more along the coast, as in the outbreak of red water in the 

 same region in August, 1907 (Kofoid, 1911). These discolored areas are usually 

 found near shore with a seaward extension of one-half to three miles. 



The length of time during which these areas may persist ranges from a 

 few days to several weeks. Torrey (1902) records the appearance of red water 

 from July 7 to Sej)tember 1, 1902, from the region of Santa Barbara to San 

 Diego. 



This discoloration has been popularly attributed to submarine earthquakes, 

 landslides, or the presence of sulphur or phosphorus discharged from submarine 

 mineral springs in the water. It is, however, caused by the sudden appearance 

 of vast multitudes of dinoflagellates in the surface plankton, and may be due 

 to the sudden and periodic enrichment under favoring conditions of temper- 

 ature and light of the coastal waters by the nitrogen-bearing upwellings conunon 

 along the shores of that part of California. 



The presence of such vast quantities of these minute organisms within a 

 limited space results in the death of coiintless myriads of them, the ensuing 

 decay producing a nauseous and penetrating stench of a most disagreeable 

 nature. These products of decay are toxic to many marine organisms, which 

 die in great abundance and are stranded on the beach by the tide. The filtrating 

 action of the beach sands also results in the accmnulation of vast quantities 

 of these organisms along the tide lines and the sands become foul with odors 

 of their decay. 



