The effect of seasons on yield and quality of agar and carrageen from selected Tanzanian red algal species.
| dc.contributor.author | Buriyo, Amelia Sylvery | |
| dc.date.accessioned | 2019-10-14T14:55:00Z | |
| dc.date.accessioned | 2020-01-07T15:45:05Z | |
| dc.date.available | 2019-10-14T14:55:00Z | |
| dc.date.available | 2020-01-07T15:45:05Z | |
| dc.date.issued | 1999 | |
| dc.description | Available in print form | en_US |
| dc.description.abstract | The effect of seasons on yield and quality of agar and carrageenan from four Tanzanian red algal species, namely Gracilaria crassa, Eucheuma den ticulatum, Sarconema filiforme and Hypnea musciformis was studied. Samples were collected from Oyster bay rocky shore, Dar es salaam. The study was carried out between June 1996 and May 1997. Seaweed samples were collected, once a month during spring low tide. Thereafter samples were dried, extracted and the resultant phycocolloid was used to determine yield and quality. Biomass and thallus nitrogen and phosphorus content were determined seasonally in four months during wet and dry Southeast monsoon (SE) and Northeast monsoon (NE) periods. Percentage ash content was determined monthly. During each sampling visit, light, temperature, salinity and pH were recorded. Meteorological data were obtained from the Directorate of Meteorology, Dar es Salaam Tanzania. Trial cultivation of Sarconema filiforme under varying light intensity and nutrient levels was carried out in the laboratory for a period of a month for every experiment. Results indicate that red algal species were most dominant in terms of species number and biomass during November to January. This may be attributed to nutrient availability (particularly N) and calmer conditions prevailing in the sea. Another algal abundance peak was observed during May to July when total nitrogen concentration in the seawater was also high, light and temperature were low. Reduced temperature and insolation serves intertidal plants from stresses induced by photoinhibition and desiccation. The mean phycocolloid yield and quality were noted to vary with seasons within the species and between species. The agar yield from G. crassa was significantly higher during the NE monsoon period (t = 3.16, P<0.05). E. den ticulatum and S. filiforme had a significantly higher mean carrageenan yield during the SE monsoon period while carrageenan yield of H. musciformis was not significantly different between the monsoons (t = 6.15, P<0.05; t = 6.54, P<0.05 and t = 0.55, P>0.05, respectively). Generally, the presence of higher carrageenan yield during the SE monsoon period could be attributed to favourable physical and nutritional conditions. Also high turbulence during this season might have signalled algae to synthesize more supporting cell wall material. The mean phycocolloid quality (gel strength) of G. crassa, S. filiforme and H. musciformis was relatively higher during the SE monsoon period though the difference between seasons was significant only in the carrageenan quallity of S. filiforme (t = 0.86, p<0.05 and t = 1.91, p>0.05, respectively). Carrageenan from E. denticulatum had significantly higher gel strength during NE monsoon period (t = 2.61, p<0.05). There was a generalized low gel strength during the rainy periods. This was due to low salinity and possibly inadequacy of essential cations for phycocolloid gelation. For S. filiforme grown in the laboratory, growth rates and carrageenan yield were significantly higher in plants grown at higher light intensity (F= 1550.73, P<0.05 and F=2047.46, P<<0.05) respectively and nitrogen-enriched growth medium (F= 458.99, P<0.05 and F= 908.95, p<<0.05) respectively. | en_US |
| dc.identifier.citation | Buriyo, A. S. (1999). The effect of seasons on yield and quality of agar and carrageen from selected Tanzanian red algal species. Master dissertation, University of Dar es Salaam. Available at (http://41.86.178.3/internetserver3.1.2/search.aspx?formtype=advanced) | en_US |
| dc.identifier.uri | http://localhost:8080/xmlui/handle/123456789/1563 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of Dar es Salaam | en_US |
| dc.subject | Algae | en_US |
| dc.subject | Tanzania | en_US |
| dc.title | The effect of seasons on yield and quality of agar and carrageen from selected Tanzanian red algal species. | en_US |
| dc.type | Thesis | en_US |