Abstract
The present paper reports an ecological work undertaken to provide experimental evidence concerning the distribution of cellulose-decomposing bacteria belonging to genus Cytophaga in sea water, in bottom sediments, and on fishing nets submerged in the sea.
Population counts were made, by means of the poured-plate method, of total population of aerobic cellulose-decomposing bacteria and numbers of Cytophagas in marine materials from Maizuru Bay,
As the media for plate counts, a weak agar gel containing inorganic nutrient salts and precipitated cellulose was employed.
Results obtained are as shown in Tables 1 and 2, and may be summarized as follows:
1) Cellulose-decomposing bacteria belonging to gems Cytophaga were widey distributed in water and mud of Maizuru Bay. In such marine materials Cytophagas constituted from 0 to 33.3% of the total number of aerobic cellulose-decomposing bacteria,
2) The minimum populations of Cytophagas were found in water containing the minimum populations of plankton.
This result suggests that there may be a certain relation between the total number of planktons and the populations of Cytophagas in water samples. Since planktons provide solid surfaces for attachment, it is not surprising that the abundance of Cytophagas is closely related so the abundance of plankton. It is already known that aerobic cellulose-decomposing bacteria belonging to the order Eubacteriales are able to develop in free-floating condition in liquid media, but most representatives of the order Myxobacteriales grow almost exclusively on submerged surfaces.
3) In the samples of fishing nets submerged in the sea Cytophagas constituted from 22.2 to 40.5% of the total number of aerobic cellulose-decomposing bacteria.
This result indicates that Cytophagas develop more excellently on submerged surfaces such as fishing nets than in free-floating condition it the sea.
Dur to the tenacious attachment property and cellulose-decomposing ability Cytophagas may play an important role in the deterioration of fishing nets submerged in the sea.
