Download Caffeine as a cause of coral bleaching: Effects of caffeine on

Caffeine as a cause of coral bleaching: Effects of caffeine on the proteins of coral
symbiont zooxanthellae
Kimberly Balazs
Mentor: Oladele Ogunseitan
If untreated, the caffeine in sewage effluent reaches the open ocean where it may affect
marine life. Studies have shown that low concentrations of caffeine can induce bleaching
in coral; i.e. caffeine causes coral to release their algal symbionts (zooxanthellae). Corals
may recover from this, but bleaching events often lead to death. We hypothesized that
caffeine causes the zooxanthellae to produce different proteins, which may lower their
ability to adhere to the coral cells. We tested this by comparing proteins of four clades of
zooxanthellae grown in low concentrations of caffeine with those grown in identical
conditions without caffeine. Representative species were chosen from four clades of
zooxanthellae to account for variation between the clades in their response to growth in
caffeine. The proteins were extracted and analyzed using SDS PAGE performed on the
PhastSystem with gradient 8-14 gels. The results indicated that our extraction procedure
was successful in producing sufficient yields of protein; however, the resolution of the
gels was too poor to show differences in the protein bands. We are now sending our
extracted proteins to the School of Biological Sciences for a more detailed analysis using
2D PAGE. Since coral reefs are the most diverse ecosystems on Earth and provide many
people with storm barriers, food, and a source of income, it is imperative that we
determine the causes of bleaching and implement policy to lessen their effects. Thus, this
research may have important implications for not only coral ecology, but also wastewater
treatment and reef management.