Effects of Cadmium on Biochemical Parameters, Viability and Bioaccumulation of Kappaphycus alvarezii

Abstract

The Rhodophyta, Kappaphycus alvarezii, is widely cultivated for its highly valuable kappa carrageenan. K. alvarezii has also been known for its capacity to absorb and accumulate excess heavy metal from its surrounding. The study was undertaken to unravel the effect of different cadmium treatments towards K. alvarezii at different exposure times by determining the biomass change percentage, algal cell viability and the changes in chlorophyll and protein content at Cd concentrations ranging from 50 to 500 μM for 5, 10 and 15 days. While there was no significant change in the percentage of the biomass change, the viability of the algal cells increased significantly with increasing Cd concentration and exposure time. This was accompanied by significant increase in protein content following similar pattern as shown by the viability of the cells. In contrast, chlorophylls a and b content decreased significantly with increasing Cd concentration. The ability of the alga to uptake Cd was also increased with increasing Cd concentrations possibly indicating that the ability of K. alvarezii to survive the high level of Cd might be due to its ability to accumulate heavy metal. The results from this research revealed the unique manner in which K. alvarezii responds to Cd stress which is unlike any other algae. Thus the findings obtained from this study may contribute important information on how macroalgae adapt to heavy metal pollution.