Preliminary Survey of the Sublittoral Flora of Halifax County

Abstract

During the autumn of 1965 and the summer of 1966, observations and sublittoral collections to a depth of 40 m were made of the benthic vegetation of the Atlantic coast of Halifax County. A total of 166 species (exclusive of crustose corallines) were recorded and distributed as 72 Rhodophyceae, 66 Phaeophyceae, 26 Chlorophyceae, 1 Xanthophyceae, and 1 Chrysophyceae. Thirty-three of these species have been recorded as new to Nova Scotia. Very few of the macrophytic species collected are exclusively sublittoral. Three distinct vegetational associations, each characteristic of a particular depth range, were recognized. From the sublittoral fringe to a depth of about 15 m, a Laminaria–Desmarestia association occurs. Below 10 m the flora is dominated by an Agarum–Ptilota association, and at 30–40 m a Phyllophora–Polysiphonia association is present. In some species morphological variations were correlated with depth.