The Effect of Salinity on Phenol and Mannitol Contents in Ascophyllum nodosum – Culture Studies.
Authors – John Paul Tiernan , Dr. Solene Connan and Dr. Dagmar Stengel
This is the abstract of a research project I did as an undergrad at the Martin Ryan Marine Science Institute at NUI Galway. Major thanks to Solene Connan who helped me out so much. Please email firstname.lastname@example.org if you would like more information on the project.
The aim of this study was to assess the effect of environmental conditions on phenol and mannitol contents of a brown seaweed. The intertidal brown alga Ascophyllum nodosum (Linnaeus) Le Jolis, was collected at two sites, Finavara and Kinvara, with different environmental conditions, particularly salinity, in Galway Bay. The algae from each site were cultured for a period of 6 weeks in different salinity treatments (34, 25, 15 and 5‰). Sampling of plants from the cultures took place at regular intervals. Plants were assayed to determine phenol and mannitol content. Previous studies had shown phenol (in situ) and mannitol (in situ and culture) contents to correlate positively with salinity. Results from this culture study showed no apparent correlation between salinity and phenol and mannitol content, however, factors other than salinity (e.g. culture stresses) had an effect. With regard to phenol content, it is suggested that the influence of salinity in previous in situ studies may have been indirectly manifested through other stresses. With regard to mannitol content, the tolerance of A. nodosum to changing salinity may explain the contrast with previous results from other fucoids. Results confirm the theory of mannitol being utilised by brown algae as a stress metabolite. The study also highlights the differences between phenol and mannitol production with regard to photosynthetic activity.