444 
The Nitrogen, Organic Carbon, and other Oxidizable Matter 
in the Bottom Muds of the River and Lakes below 
Chillicothe, 1913—1914 
1. Borrom Mups oF THE ILLINOIS RIVER CHANNEL, 1913 
Mud samples taken in the Illinois River channel between Chillicothe 
and Kampsville in March and July—October, 1913, showed a rather wide 
variation in the amounts of nitrogen present, as expressed in terms of 
percentage of dry matter, but both in early spring and late summer 
agreed in showing a higher average above than below Havana. In 
percentage figures, as stated, five samples from above Havana, all 
months taken together, averaged 0.306% nitrogen, or 61% richer than 
the five samples taken on approximately the same dates at stations be- 
low Havana, which averaged 0.189%. A lesser actual difference in 
average nitrogen content is shown for the stations above and below Ha- 
vana, when we take into account the specific gravity and the moisture 
percentages of the samples and calculate average values of nitrogen by 
weight for a given area to a depth (3 inches) supposed to approximate 
the average depth of cut into the soft bottom by the dipper in taking 
the samples. The average number of pounds of nitrogen to the acre, 
figured in this way, was 1,918 for the stations above Havana; and only 
26% less, or 1,417 lbs. per acre for the stations between Lagrange dam 
and Kampsville, in which the specific gravity was visibly higher and the 
moisture-content lower. ; 
The organic carbon per acre figures out, both above and below Ha- 
vana, at about 8 times the nitrogen, the averages standing at 14,111 lbs. 
per acre for the stations above and 11,322 lbs. for the stations below 
Havana. The total oxidizable matter (which includes both the nitrogen 
and the organic carbon, as well as various other substances, some of 
them of a mineral nature), figured in the same way, averaged 48,345 lbs. 
per acre to a depth of 3 inches in the river channel above Havana, and 
31,869 lbs. per acre below Havana. 
Compared with the stocks of nitrogen and total oxidizable matter 
(dry weight) in the muds either above or below Havana, the total acre- 
poundages of dry matter or nitrogen represented by the bottom inverte- 
‘brate population of July—October, 1913, are extremely small, however 
liberally figured. Taking the average bottom-fauna stocks of the river 
between Chillicothe and Havana (the richest section) as 555 Ibs. per 
acre (see table, page 412), and assuming a dry-matter content of 
about 10% and a percentage of nitrogen to dry matter of 7%, the dry 
weight of the average stock of bottom fauna on one acre would stand 
at 55 pounds, or about 1/900 of the dry weight of the total oxidizable 
matter per acre in the channel mud of that reach, and the contained 
nitrogen at less than 4 pounds, or about 1/500 of the total nitrogen per 
acre. 
