Academia, E., Teeter, K., Phillips, C., Kaiser, K., Coelho, V. R.

Preliminary results on the effects of shading on thermal bleaching in Pocillopora damicornis

2011

Twenty-fifth National Conference on Undergraduate Research (Abstracts), Poster Session 5, March 3 - April 2, 2011, Ithaca, New York

"Thermal stress can lead to the expulsion of algal symbionts in corals, causing bleaching - a phenomenon likely to become more common with global warming. Bleaching is caused not only by high temperatures but also by high light intensity. In an effort to further understand the effects of temperature and irradiance on bleaching, two control and four experimental treatments were set up, using aquaria with 10-12 corals in each. All corals were originally from America Samoa. Controls were set at 26 and 29 degrees Celsius, and treatments at 31 degrees Celsius. Some aquaria were not shaded, while others received 50% or 75% shading. Pocillopora damicornis was very sensitive to high temperatures, bleaching soon after the experiment started. We hypothesized that we would find significantly different bleaching curves between control and experimental treatments, and significant bleaching trends for experimental treatments only. Statistical analysis did not yield a clear pattern, however, significant differences were found in pair-wise bleaching curve comparisons, primarily between the 26 degrees Celsius control and all other aquaria. There was a bleaching trend in control as well as experimental corals. Bleaching curves for P. damicornis showed complete bleaching in all treatments except for the 26 degrees Celsius control, implicating that even in usual mean high temperatures, the corals are already under stress. Due to the relatively small sample size and the negative response of the corals to the transportation process, it is possible that our results reflect greater sensitivities to stressful conditions than would be expected in nature. We recommend more replicates to be done in lab, accompanied by complimentary field experiments."

NOAA award NA09NMF4630105

NA09NMF4630105