Notes on the Growth and Ultrastructure of Biddulphia Laevis Ehr. (Bacillariophyceae) in the Maumee River, Ohio

Author Institution: Department of Biological Sciences, Bowling Green State UniversityMasses of the chain-forming diatom Biddulphia laevis Ehr. were observed in the Maumee River in the summer of 1981. Standing crop of this diatom was determined at different thalli portions of its green algal substrate, Cladophora glomerata (L.) Kutz. Ultrastructural observations of valve morphology with SEM indicate this species is typical of other biddulphioid diatoms, except in the structure of the ocellus-like process, which appears to be intermediate between a typical rimless pseudocellus and the thickened rim of an ocellus. Attachment of B. laevis to Cladophora and the zigzag filamentous nature of the chains was observed with SEM and noted to be similar to that of marine centric diatoms of the same type