Colonization of periphytic algae on glass slides was studied during a
5-week exposure period at four current regimes, comprising a static po
ol and three current velocities. After the 4th week, substrata were tr
ansferred from each current regime to the others to gain some insight
into the regulatory influence of water current on the structure of the
periphytic community. An inverse relationship between periphytic accu
mulation and current velocity was observed. Unlike earlier reports sho
wing greater biomass accumulation at higher current velocities due to
stimulatory effect of water current, no such effect was noticed in the
present study. This points towards a preference of the majority of sp
ecies for the pool. Thirty-four species of diatoms constituted the per
iphytic community, and three species of green algae occurred sporadica
lly. Preferences of some common species for current regimes were deter
mined: pool for Gomphonema parvulum and Gomphonema lanceolatum; 10-14
cm s(-1) for Navicula cryptocephala; and 18-21 cm s(-1) for Gomphonema
olivaceum, Caloneis bacillum and Pinnularia gibba. After colonization
in the pool, the total biovolume of Surirella ovata increased signifi
cantly at intermediate current velocities which suggested there was a
stimulatory effect of water current. (C) 1998 Elsevier Science B.V.