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Browsing by Author "Batista, Miguel Melo"

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  • Reproduction and cultivation of asparagopsis taxiformis (Delile) trevisan
    Publication . Batista, Miguel Melo; Santos, Rui; Martins, Gustavo M.
    Seaweeds have been receiving increased interest from the fisheries and aquaculture industries in recent years, with red algae continuing to be one of the more important components of seaweed aquaculture representing 54% of the harvested biomass (around US$ 6.3 billion). These seaweeds are important for both food and diverse of biotechnology usages. Asparagopsis taxiformis, a characteristic red alga, has been receiving increased attention for its biotechnological applications, the most interesting one being its ability to reduce methane emissions on the cattle. A. taxiformis presents a triphasic life history, passing from gametophyte to carposporophyte and finally to tetrasporophyte. The conditions for the lab manipulation and survival of this species are still not know, taking in consideration the difficulty of maintaining gametophyte cultures. In this work, some abiotic factors affecting gametophyte maintenance and reproduction were experimentally tested. A. taxiformis gametophyte did not survive any common pretreatment used, only surviving in culture if cleaned of epizoa in sterilized filtered seawater and by selecting the less epiphyted individuals. A. taxiformis showed the highest growth rate when cultivated at 15 ºC, not growing at 20 ºC and dying at 25 ºC. An industrial fertilizer used showed similar growth rates compared to the Von Stosch medium. Photoperiod manipulation did not result in any sexual differentiation on the gametophytes. A low stock density (1 g/L) was required since at higher densities there was reduced (2 g/L) or no (4g/L) growth rate. A. taxiformis was able to grow at both 20 and 40 μmol photon m-2 s-1, showing slightly higher (but not significant) growth rates at the latter. Attempts at inducing carposporophyte formation were unsuccessful. Temperature and light intensity were the two most important factors to maintain gametophyte culture.
    2020-12-09Master thesis Open access Show more