| || || Shah, Sofia Banu.|
| || || Study of heavy metal accumulation in scleractinian corals of Viti Levu, Fiji Islands|
Author:Shah, Sofia Banu.
Institution: University of the South Pacific.
Call No.: pac In Process
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: The concentrations of heavy metals (Copper, Lead, Zinc, Cadmium and Iron), together with the partitioning of the metals in the skeleton, tissue and zooxanthellae have been studied in three different coral families. The variation of metals in Acropora formosa, Pocillopora damicornis and Porites spp was also looked into. Heavy metal accumulation rates were studied for Acropora formosa and Pocillopora damicornis for a period of five days. Study sites included Suva and Nukubuco reefs, Coral Coast and the Great Astrolabe Reef. Suva and Nukubuco reefs (barrier) lie off the coast of Suva peninsula, and are characterized by significant terrigenous inputs from Rewa River, and Vatuwaqa River, together with waste discharge from nearby industries. Coral Coast lies approximately, 190 Km along the Queens Highway between Nadi and Suva. A great number of hotels, motels and resorts lie along the coast. It is an area of tourist attraction due to the fact that it has white sandy beaches, and the presence of fringing reefs. The Great Astrolabe Reef (Kadavu) is an area, which is considered to be pristine, since the population density is less and it is almost free from major developments. High concentrations of metals were determined for the zooxanthellae, than the tissue and then the skeleton, suggesting that the zooxanthellae are responsible for the heavy metal uptake in corals. This was the case for nearly all the corals studied. There is variation in the uptake of heavy metals, suggesting that Porites spp seem to accumulate lower concentration of the metals than Acropora or Pocillopora. Corals from The Great v Astrolabe Reef had lower heavy metal concentrations than that from the Coral Coast or the southern reefs, hence represents an excellent reference site. Dose response curves show that as the nominal concentration increases, the uptake of heavy metals by the corals also increases. Two bioassays were carried out with nominal concentrations of 0, 0.01, 0.1 and 0.5 ppm of heavy metal solution. Variations in the uptake of heavy metals by the corals occurred for each bioassay. High concentrations of Pb as well as Fe seem to be accumulated in the corals for different bioassays, when compared to other metals. Lead and iron concentrations as high as 2.5 and 0.8 ppm respectively had been transferred to the corals. There were significant differences in the uptake of the metals (p<0.05, for regression analysis). The total amounts of heavy metals transferred to the corals in the aquaria were below the method detection limit, especially for the nominal concentrations of 0 and 0.01 ppm. Zooxanthellae were lost to the surrounding aquaria waters as a result of stress on the corals. vi