Oxygene Absorption of Lake Muds (lst report)

Abstract

The oxygen absorption of lake muds in a number of lakes in Japan, such as L. Takasuka, L. Kitaura, L. Tyûzenzi, etc., were determined by the author. Five grs. of fresh lake mud, whose oxygen content was desired, were placed in watre, then into a bottle of 280cc capacity, and then shaken vigorously 200 times and left to stand in a dark chamber for 4 hours. The decrease of the oxygen in the water was measured by Winklers standard method, following which the quantity of oxygen absorped by the humid muds at different temperatures were reduced to the equivalent .value of a dry sample of 1gr. at l5°C.
The horizontal and vertical distributions of oxygen absorption in lakes were studied from the limnological point of view, with the following results:
1) The horizontal distribution of oxygen absorption of lake muds in takes is controlled by the lake stream.
2) In non-stagnent lakes (S. Yoshimura's order II), there is an apparent relation between oxygen absorption of lake muds and depth, but there is no such relation in stagnent lakes (order III).
3) No relation, between oxygen absorption and coarse debris was observed in any lake type, although a positive relation was found between the O₂-absorption of lake muds and fine debris which, though evident in eutrophic lakes, is obscure in oligotrophies.
4) A linear relation between the O₂-acs. of lake muds an Loss Ignition was observed, the gradient of the line varying gradually with the fertility of the lake.
From these fact the author concludes that the oxygen absorbing capacity of lake muds depend upon its carbon contents.
5) In oligotrophic lakes, the influence of reduced substances, such as hydrogen sulfide, ferric iron, methane. etc., on the absorbing capacity of lake muds, is important.
6) From his experiments it seems that there is no relation between microorganisms and decomposition of lake muds.