LIMNOLOGICAL STUDIES OF KARLUK LAKE 
411 
TRANSPARENCY OF WATER 
The transparency of the water was measured by means of the Secchi disk. The 
results of the readings in the three lakes are given in Table 2. In general, the water 
of Karluk Lake was more transparent than that of Thumb and O’Malley Lakes. 
Thumb Lake was the least transparent of the three. Karluk Lake was more trans- 
parent in 1928 than in either of the other years represented in the table. 
Table 2. — Transparency of the water in Karluk, Thumb, and O’Malley Lakes 
[The readings of the .Secchi disk are indicated in meters and they show the depth at which the disk disappeared from view] 
Karluk Lake 
Thumb Lake 
O’Malley Lake 
Date 
Depth 
Date 
Depth 
Date 
Depth 
July 10, 1928 
8. 6 
July 9, 1928 
2. 5 
July 10, 1929 
5. 5 
Sept. 3, 1928 - . 
8.0 
Sept. 3, 1928. 
3.0 
Sept. 12, 1929 
3. 8 
July 9, 1929 
5. 5 
July 11, 1929 
July 15, 1930- _ 
4. 0 
Sept. 7, 1929 
4.5 
Sept. 7, 1929 
2.5 
Sept. 5, 1930 
4. 0 
July 12, 1930- — 
7.5 
July 13, 1930 
2.6 
Sept. 9, 1930 - - 
7.8 
Sept. 6, 1930 
2.0 
TEMPERATURES 
The climate of Kodiak Island, on which Karluk Lake is situated, is temperate. 
The lake lies in the Pacific coast climatic zone of Alaska, and this region possesses a 
marine climate, with a large amount of cloudy weather. There is no permanent settle- 
ment in the vicinity of Karluk Lake, and the nearest weather-observing station is located 
at the village of Kodiak on the eastern end of Kodiak Island, about 160 kilometers 
(100 miles) from the lake. Table 3 shows the range of variation of atmospheric 
temperatures at Kodiak from 1926 to 1930, inclusive, as well as the mean temperature 
for these years. The United States Weather Bureau reports that temperatures were 
above normal throughout the year in 1926 at nearly all Alaskan stations, considerably 
exceeding all previous records. The mean annual temperature was about normal 
in 1927 and 1930 and just a little above normal in 1928 and 1929. 
Table 3. — Range of air temperatures at Kodiak on Kodiak Island, Alaska, during the years 1926- 
1930, inclusive, and the mean annual temperature for these five years 
The mean monthly temperature was lowest in Februarj^, 1926, being 0.5° C. or 
33° F., but December was almost as low, namely, 0.7° C. or 33.2° F. The mean 
monthly temperature was lowest in March from 1927 to 1929; it was —1.8° C. 
(28.7° F.) in 1927, -1.3° C. (29.7° F.) in 1928, and -0.3° C. (31.4° F.) in 1929. 
February had the lowest mean in 1930, namely, —5.3° C. (22.5° F.). The monthly 
mean was highest in August in 1926 to 1928, inclusive; it was 13.7° C. (56.6° F.) in 
1926, 11.7° C. (53° F.) in 1927, and 12° C. (53.4° F.) in 1928. In 1929 the monthly 
means were the same for July and August, namely, 13.2° C. (55.8° F.). It was 
highest in August, 1930, namely, 13.5° C. (56.3° F.). 
