In Area III turbidities ranged from 70.1 to 25, which parallels 

 the range in Area II. The significant point is that whereas oysters 

 were usually not feeding in Area II they usually were feeding in 

 Area III, 



The relative turbidity which existed at the different stations 

 in these surveys had no direct effect on the feeding activity of 

 the oysters or in causing the observed mortalities, 



Hjydrogen Ion Concentration 



Further evidence for the disturbed condition of the water in 

 Mississippi Sound from January to June, 1949 is gained from the 

 tests made for pH of the water samples. The term pH is a con- 

 venient method for stating the relative acidity or alkalinity of 

 a solution. In the case of pure distilled water, the pH is 7,0 

 or neutral. Higher figures Indicates a basic solution and lower 

 ones Indicate an acidic solution. Sea water is nozmally alkaline, 

 having a range In pH from 7,5 to 8,4, 



In restricted bodies of water ouch as Lake Meohant and Miss- 

 issippi Sound, pH values would be expected to differ from the nozmal 

 range of sea water, lAif ortunately , pH values for these areas In 

 other years are not known, but the values found on these surveys 

 indicate a range much greater than might be expected in Mississippi 

 Sound, 



In Lake Mechant in April, the salinity varied at four 

 stations from 0,5 to 7,2 ppm. The pH was constant at 6,9, This 

 very slightly acid condition may be explained on the basis of the 

 hydrogen sulphide decomposition taking place in the surrounding 

 marshlands which drain into the lake, I believe this acid condition 

 is normal for the area. 



In Mississippi Sovind dxiring the first week of March, salinities 

 at five stations varied from 0,2 to 0.8 ppm. The pH values ranged 

 from 8,6 to 9.0 indicating a quite alkaline condition of the water. 

 At these same stations in the latter part of April, the bottom salinity 

 varied from 0,2 to 0,9 ppm, the same as in March, iriille the hydrogen ion 

 concentration had decreased to such an extent that the water at most 

 stations was 6,9 and only at one station was it as high as 7.1, 



These values indicate that the pH was independent of salinity 

 levels in the Sound. The wide variance in pH must be attributed 

 to variations in the sources of fresh water flowing into the Sound 

 from the several rivers. The ranges in pH are not such as would be 

 expected to cause harmful effects on the oyster population. 



17 



