An investigation into the taxonomy, distribution, seasonality and phenology of Laminariaceae (Phaeophyceae) in Atlantic Canada
University of New Brunswick
The Laminariaceae is one of eight families in the order Laminariales ( the kelps) and most members occur in the northern hemisphere. A recent molecular study in Atlantic Canada confirmed the presence of Laminaria digitata, Saccharina latissima and a third genetic species, which was later attributed to S. groenlandica. This third genetic species was likely overlooked in this region due to its morphological similarity to L. digitata and S. latissima. The main objective of this thesis was to investigate the taxonomy, distribution and seasonality of the Laminariaceae in Atlantic Canada and verify the taxonomic identity of the North American genetic species attributed to S. groenlandica. First, I clarified the taxonomic confusion surrounding the North American genetic species attributed to S. groenlandica. I determined that the North American genetic species currently attributed to S. groenlandica is correctly attributed to L. nigripes; therefore, Saccharina nigripes (J. Agardh) C. Longtin et G.W. Saunders comb. nov. was established and includes North American collections previously attributed to S. groenlandica. Second, I utilized molecular tools to determine the relative abundances of L. digitata, S. nigripes and S. latissima in differing habitats in the Bay of Fundy intertidal zone. I determined that the digitate morphology of S. nigripes can be the major contributor to Laminariaceae community structure at moderate and wave-exposed sites in the Bay of Fundy; however, its abundance fluctuates depending on the year. Third, I attempted to clarify the seasonality and phenology of the Laminariaceae in the Maritime Provinces. Due to the morphological similarity of S. nigripes to L. digitata and S. latissima previous literature on the seasonality and phenology of S. latissima and L. digitata may have inadvertently included S. nigripes. Saccharina nigripes was rare at the study site in the year this study was performed and I was unable to determine its seasonality and phenology. However, I did determine that the seasonality and phenology of L. digitata and S. latissima in this region are consistent with previous reports in Atlantic Canada, and the presence of S. nigripes is unlikely to impact previous literature on the seasonality and phenology of L. digitata and S. latissima.