EFFECTS OF COPPER ORE ON THE ECOLOGY OF A LAGOON 



By Kenneth T. Marvin and Larence M. Lansford, Chemists, and Ray S. Wheeler, Fishery Research Biologist, 



Bureau of Commercial Fisheries 



Sudden, immense increase in the plankton popu- 

 lation has resulted in extensive destruction of 

 commercially important fish and shellfish. Some- 

 times this fish-killing plague is known as "red 

 tide" because of the amber to dull-red discolora- 

 tion of the water. 



The organism present in frequent occurrences 

 of red tide in OfTats Bayou, Galveston (Tex.) was 

 identified by Gunter (1942), and by Gates and 

 Wilson (1960), as Gonyaulai monilata. Oymno- 

 dinium breve was identified by Davis (1948) as the 

 cause of destructive red tide blooms that have 

 occiured off the west coast of Florida at irregular 

 intervals since, at least, 1844 (Feinstein and others, 

 1955). 



Following the outbreak of destructive G. breve 

 blooms in 1946 and 1947, the U.S. Bureau of Com- 

 mercial Fisheries began a study of the organism 

 and the environmental factors limiting or promot- 

 ing its growth, to develop, if possible, a means 

 of controlling or, at least, reducing the occurrence 

 of these lethal outbreaks. 



The toxic property of copper has been employed 

 elsewhere with varying degrees of success in re- 

 lated occurrences of plankton blooms. Experi- 

 ments in the U.vS. Fish and Wildlife Service Labo- 

 ratory have demonstrated that the minimum 

 amount of dissolved copper lethal to G. breve is 

 about 0.5 microgram atoms per liter (0.03 p. p.m.). 

 An experiment was designed therefore to test the 

 feasibility of using immersed copper ore as a source 

 of copper in lethal concentrations through its re- 

 lease into solutions over a rather long period of 

 time. 



We wisli to express our appreciation to Mi's. 

 Zoula Zein-Eldin, William Wilson, and Di-s. David 

 Aldrich and Abraiiam Fleminger, who conilucted 

 many of the analyses, and to the Morenco Mining 

 Branch of the Phelps Dodge Copper Corijonitioii 

 for furnishing the copper ore for the experiment. 



COPPER ORE EXPERIMENT 



The experiment was designed to determine 

 whether or not immersed ore would affect the 

 flora and fauna. This would be decided by com- 

 paring chemical and biological studies made before 

 and after tlie addition of ore. 



Questions to be resolved were the foUowhig: 



(1) Could copper concentration in a body of 

 water be raised to a level lethal to G. breve by the 

 permanent exposure of a reasonable amount of 

 copper ore? (2) Would the copper concentration 

 of the water remain at a constant level? (3) 

 Would the copper liave an adverse effect on other 

 marine organisms? 



To obtain an estimate of the amount of copper 

 ore needed, laboratory studies were made on the 

 solubility of the copper in various amounts of ore 

 in tanks of sea water. On the basis of the results 

 of these tests, 20 tons of ore seemed a reasonable 

 amount with which to start. Subsequent dosages, 

 if necessary, would be based on the results of the 

 first addition. We used a sulphide ore that con- 

 tained approximately 1 percent copper and 3.5 

 percent iron. Tiie particle size varied from dust 

 to coarse gravel. 



The questions were answered (1) by observing 

 the effects of the ore on two indicator organisms." 

 (2) by determining tlie level of the copper con- 

 centration maintained, and (3) by comparing 

 ecological conditions of tlie lagoon before and after 

 the addition of tlie ore. Comparisons were based 

 on gross differences in productivity of tiie water, 

 on significant changes in mortality rates of organ- 

 isms, and on variation in barnacle setting rate. 

 Chlorophyll and zooplankton analyses were used 

 as indicators of productivity. Mortality rate 



1 Laboratory pxixrimi'iit.s ilemonstrated that tlie toloranw of these organ- 

 isms to copper was approximately the same as that of (Jymiiorfiiiiiim hrtre. 

 One of thes*'. Prorocrntrum sp.. was placed ii\ the laROon in dialysis bacs. 

 another. Gymnodintum spkndrm. occurred naturally in the lagoon. 



Note.— Approved for publioUlon SepU'raber 12. 1960. Fishery Bulletin 1 M 



153 



