154 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



studies were made of Oymnodinium splendens that 

 occurred in the water, and of organisms from the 

 live car: 03'sters, Crassostrea virginica; mullet, 

 Mugil cephalus; and two snails, Littorina irrorata 

 and Thais species. 



Our field activities were conducted in a man- 

 made lagoon located on the eastern end of Galves- 

 ton Island (fig. 1). The lagoon, 1.1 statute miles 

 long, has an estimated volume of about 230 acre- 

 feet and is connected to the Galveston Ship 

 Channel by seven 36-inch cement culverts. 

 Chemical and biological samples were taken at 

 eight stations. Samples were collected three to 

 four times a week until the first ore addition of 20 

 tons was made and then twice a week. Several 

 months after the final addition of 40 tons, the rate 

 was reduced to once a week and the number of 

 stations sampled to three (stations 1, 4, and 7). 

 During collection trips samples were taken for 

 salinity, copper, chlorophyll, G. splendens, and 

 zooplankton analyses. The water for these was 

 taken with a stainless steel neoprene impeller 

 pump. During collections tlie intake end of the 

 polyethylene connection hose was continuously 

 raised and lowered from a few inches of the bottom 

 to the surface. Thus, the samples were represent- 



ative of the entire column. A 4-inch Secchi disc 

 reading was also taken at each station. Once or 

 twice a week, depending on weather conditions, a 

 count was made of the organisms in the live cars 

 anchored at each station. At weekly intervals, 

 barnacle-setting plates were suspended 2 feet below 

 the surface at each station. These plates were 

 replaced every week. 



Before each addition of ore, dialysis bags con- 

 taining cultures of known concentrations of Proro- 

 centrum. sp. were suspended in perforated polyeth- 

 ylene bottles 2 feet below the surface at stations 2, 

 4, 5, 6, and 7. These bottles were replaced so that 

 some of them remained in the water for 2 days and 

 others for 4 days. The first of these experiments 

 was discontinued 2 weeks after the first ore addi- 

 tion and the second, 1 week after the second addi- 

 tion. 



ANALYTICAL METHODS 



Chlorophyll 



The chlorophyll analyses consisted of estimations 

 of chlorophyll a, b, and c in acetone extracts of 

 plant and animal material. The method em- 

 ployed was that of Riciiards with Thompson 

 (1952) as modified by Creitz and Richards (1955). 



GULF OF MEXICO 



Figure 1. — East Lagoon station locations selected for the copper ore experiment. 



