OBSERVATIONS ON SILICA-SCALED FLAGELLATES (CHRYSOPHYCEAE AND SYNUROPHYCEAE) IN THE BRACKISH-WATER OF POJO BAY, SW COAST OF FINLAND

Silica-scaled flagellates (Chrysophyceae and Synurophyceae) in Pojo Ba y, SW coast of Finland were studied by light and transmission electron microscopy. Eighty-nine net and water samples were collected fortnigh tly during the period 22 May 1990 and 5 May 1991 from five stations (I , III, V, VA, VI) in different parts of the bay. As the water quality changes gradually from the innermost part of the bay towards the open sea, each station represents different environmental conditions. Altog ether 51 silica-scaled flagellate taxa were identified, of which nine were new to Finland. The 51 taxa belonged to the genera Mallomonas (24 taxa), Synura (4), Chrysosphaerella (3), Spiniferomonas (7), Paraphys omonas (12) and Polylepidomonas (1). In addition, three types of Mallo monas scales, not identified with certainty, and two types of loose Pa raphysomonas scales were found. Environmental parameters measured were water temperature, pH and salinity. The ecology of silica-scale beari ng flagellates in the hydrographically complicated brackish water Pojo Bay is discussed. Notice is also taken of the reliable determination of scaled chrysophytes and synurophytes by means of light microscopy.