LIMNOLOGICAL STUDIES OF KARLUK LAKE 
433 
6. The water yielded from 5 milligrams to a little more than 6 milligrams of 
calcium per liter and from a little more than 3 to almost 6 milligrams of magnesium 
per liter. 
7. The bottom deposits contained from 60 to 73 per cent of silica with only 
small percentages of calcium and magnesium. 
8. The quantity of phosphorus, silica, and nitrogen was somewhat larger in 
Thumb and O’Malley Lakes than in Karluk Lake. 
9. Larger amounts of carbon dioxide, silica, ammonia, and nitrate nitrogen 
were found in some of the affluents than in the surface water of Karluk Lake. 
10. The decomposition of the dead salmon affects the chemical status of the 
water in the three lakes and their affluents. 
1 1 . The net zooplankton of Karluk Lake was character zed by a large population 
of Rotifera. 
12. The phytoplankton of this lake consisted chiefly of green algae and diatoms. 
These two forms were more abundant in July than in September. 
13. In general, the net plankton was more abundant in Karluk Lake than in 
four of the Finger Lakes of New York and in two of the western lakes. 
14 The net zooplankton of Thumb Lake was more abundant than that of the 
upper 10 meters of Karluk Lake. The same was true of the phytoplankton. 
15. In general, the net plankton was not as abundant in O’Malley Lake as in 
Thumb Lake. 
16. The rich crop of plankton produced by these lakes is due, in part at least, 
to fertilizing substances contributed to their waters by the decomposing carcasses of 
the salmon. 
17. The large crop of plankton furnishes an abundant supply of food for the 
young salmon and, as a result, the fingerling salmon of Karluk Lake are unusually 
large and sturdy. 
LITERATURE CITED 
Atwater, W. 0. 
1888. The chemical composition and nutritive values of food-fishes and aquatic invertebrates. 
Report, U. S. Commissioner of Fish and Fisheries, Part XVI, 1888 (1892), pp. 679-8,68. 
Washington. 
Birge, Edward A. 
1915. The heat budgets of American and European lakes. Transactions, Wisconsin Academy 
of Sciences, Arts and Letters, vol. 18, No. 1, 1915, pp. 1-47. Madison. 
Birge, Edward A., and Chancey Jtjday. 
1914. A limnological study of the Finger Lakes of New York. Bulletin, U. S. Bureau of 
Fisheries, Vol. XXXII, 1912 (1914), pp. 525-609, 22 figs., Pis. CXI-CXVI. Washing- 
ton. 
1922. The inland lakes of Wisconsin. The plankton. I. Its quantity and chemical composi- 
tion. Bulletin No. 64, Wisconsin Geology and Natural History Survey, 1922, 222 pp., 
46 figs. Madison. 
Birge, E. A., and W. H. Rich. 
1927. Observations on Karluk Lake, Alaska. Ecology, vol. 8, No. 3, July, 1927, p. 384. 
Black, C. S. 
1929. Chemical analyses of lake deposits. Transactions, Wisconsin Academy of Sciences, 
Arts and Letters, vol. 24, pp. 127-133. Madison. 
Emszt, K. 
1911. Die chemische Zusammensetzung des Schlammes und des Untergrundes vom Balaton- 
Boden. Resultate der wissensch. Erforsch. des Balatonsees, Bd. 1, Heft 1, pp. 1-17. 
Vienna. 
