418 
BULLETIN OF THE BUREAU OF FISHERIES 
The residues obtained from the Karluk samples of water ranged from a little more 
than .30 to 34 milligrams per liter. The surface and bottom samples yielded nearly 
the same amounts of residue in the four sets taken in 1930. The residues from 
O’Malley Lake were somewhat smaller than those from Karluk Lake. While the 
July sample from Thumb Lake was about the same as those from Karluk Lake, the 
September sample from the former was distinctly larger than those of the latter. 
The quantity of silica was substantially the same in Karluk and Thumb Lakes, 
but a somewhat larger amount was found in the O’Malley samples. The amount of 
calcium was approximately the same in the three lakes, but the September sample 
from Thumb Lake yielded a somewhat larger quantity than any of the others. The 
quantity of magnesium also was not very different in the various samples; in general 
the amount of magnesium was somewhat smaller than that of calcium. The quan- 
tity of phosphorus was about the same in Karluk and O’Malley Lakes, but about 
twice as much was found in the Thumb Lake samples as in those from the other two 
lakes. This extra quantity of phosphorus in Thumb Lake was undoubtedly derived 
from the decomposing carcasses of the red salmon. 
Table 9. — Chemical analyses of residues from Karluk, Thumb, and O’Malley Lakes 
[The results are indicated in milligrams per liter of water] 
The results of the temperature and chemical observations that were made on 10 
affluents of Karluk Lake during the summer of 1927 are shown in Table 10. The 
temperature of the water in these streams was lower than that of the surface water 
of Karluk Lake during that season. In the various streams the temperature ranged 
from a minimum of 4.2° C. (39.5° F.) in Little Lagoon Creek on July 29, 1927, to a 
maximum of 13° C. (55.4° F.) in O’Malley River on July 17, 1927. The surface 
temperature of Karluk Lake in 1927 varied from 11° C. (51.8° F.) to 11.4° C. (52.5° F.). 
All of the streams are relatively short and have rapid currents, so that the water is 
not warmed very much on its way to the lake. (See fig. 1.) 
The hydrogen-ion concentration of the stream waters varied from pH 6.8 to 
pH 8.0, while that of the surface water of Karluk Lake was more alkaline, ranging 
from pH 8.2 to pH 8.6. 
The free carbon dioxide of the stream waters varied from a minimum of 1 milli- 
gram to a maximum of 6.5 milligrams per liter, while the average amount in the sur- 
face water of Karluk Lake was 1 milligram per liter. In general the stream waters 
yielded a somewhat larger amount of fixed or bound carbon dioxide than the surface 
water of Karluk Lake. They contained from 10.5 to 12 milligrams per liter, with a 
