Masters Theses

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Browsing Masters Theses by Author "Ilomo, Ophery Ozias"

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    Temporal and spatial variation in stable isotope and heavy metals in sediment and coral reef of the coastal marine areas of Tanzania
    (University of Dar es Salaam, 2017) Ilomo, Ophery Ozias
    Trace metals concentrations, carbon and total nitrogen contents, coral growth rates, CaCO3 content, Sr/Ca ratio, δ13C, δ15N and δ18O of both the bulk sediment and coral cores retrieved mainly between the land and the fringing reefs off Dar es Salaam City and off Zanzibar Town were used to (i) assess levels of contamination; (ii) document temporal and spatial variation in anthropogenic perturbation of the marine environment and (iii) reconstruct sea surface temperature (SST) on different timescales. The results showed metal concentrations in both sediments and coral samples were significantly higher off Dar es Salaam as compared to Zanzibar sites (P<0.01). The elevated degree of heavy metals contamination (Cd>2) and enrichment (EF>1) suggesting an increase in anthropogenic pollution resulting from discharge of untreated industrial and domestic effluents. The δ13C and δ18O averaging 1.18‰ and 1.79 ‰ respectively were more enriched in 13C and 18O, suggesting that the sediment contains carbonate originating mainly from marine shallow waters. Lower enrichment of 15N (average 1.96 ‰) were probably due to low primary productivity and inflow of terrestrial sources in the Zanzibar channel. The Porites coral growth rate was between 7 to 12 mm yr-1 and SST variability was observable. The lowest SST was in the year 1710 probably representing the little ice age. The reconstructed and recent instrumental SST data are positively correlated (r=0.7, P<0.01). Remarkable temporal increase in N-content in corals (0.01 to 0.30%) and the elevated δ15N at Tanga (7.04‰) and Dar es Salaam (9.78‰) might be due to anthropogenic activities. Authorities are advised to establish a strict industrial and domestic effluents management framework to municipalities and industries to prevent further pollution.