T. Timm, TUBIFEX TUBIFEX (MULLER, 1774) (OLIGOCHAETA, TUBIFICIDAE) IN THE PROFUNDAL OF ESTONIAN LAKES, Internationale Revue der gesamten Hydrobiologie, 81(4), 1996, pp. 589-596
Tubifex tubifex (MULLER, 1774) was found in the profundal of 23 Estoni
an lakes out of the 187 lakes where oligochaetes were met in the deepe
r zone: in 4 cases as the single tubificid species but usually togethe
r with Potamothrix hammoniensis (MICHAELSEN) dominating in almost all
lakes. T. tubifex was abundant and large in size in the profundal of a
few lakes with mesotrophic features but scarce and dwarfish (if not l
acking) in the common eutrophic ones. Observations in aquaria demonstr
ate that its occurrence in eutrophic lakes is not limited by the bacte
rial food. Some kind of competition with P. hammoniensis can be suppos
ed but no direct evidence exists. Recent colonization of the profundal
of an eutrophic lake by T. tubifex, probably from the littoral of the
same lake, was observed.