ENVIRONMENTAL FACTORS, PLANT RESPONSES, AND COLONY GROWTH IN RELATION TO TUBE-DWELLING DIATOM BLOOMS IN THE BAY OF FUNDY, CANADA, WITH A REVIEW OF THE BIOLOGY OF TUBE-DWELLING DIATOMS

Abstract

Salinity, temperature, and nutrient conditions were recorded during the winter-spring bloom of tube-dwelling diatoms and responses to salinity and photon flux density were measured for two species of contrasting occurrence: Parlibellus [Navicula] delognei f. ellipticus and Berkeleya rutilans. The Parlibellus is hypothesized to be cryophilic. Its colonies senesce before being consumed by grazing snails. Growth of P. dehgnei and P. berkeleyi [N. pseudocomoides] can be traced with the carbohydrate-staining dye Calcofluor White M2R, but B. rutilans does not take the stain, probably due to the protein in its outer tube layers. A successful cultivation system using flowing seawater was devised for growing colonies from cuttings. A review of the literature on tube-dwelling diatom biology is presented with a discussion of some key questions that need work and of ways in which these apparently facultative colony builders might provide tools for studying biological phenomena.