Current Research and Research Interests

M.S. Thesis:

Variability in the effects of flow and temperature on the growth and photophysiology of a reef building coral in Moorea, French Polynesia

Water motion has wide-ranging effects on scleractinians, particularly during thermal bleaching when increased flow may aid in resistance to high temperature. Increased flow removes photosynthetically-derived oxygen radicals, causing greater efficiency of PSII and conferring resistance to bleaching. However, enhanced flow can have both positive and negative effects on coral photophysiology (light-adapted yield, QY); modest increases benefit QY, while larger increases can have detrimental effects, suggesting that there is a threshold effect in QY along a flow continuum. To reconcile these opposing trends, we first compared the growth of juvenile Porites sp. among flow microenvironments to determine whether flow affects growth with a comparable threshold effect, reasoning that this might reflect a fitness consequence of similar influence on QY. Second, with juvenile Porites sp., we used a flume to test the hypothesis that an interaction between flow and temperature could explain the contrasting effects of flow on QY. Growth of Porites sp. in a lagoon environment responded with the anticipated threshold effect. In the flume, QY at ambient temperature (28.3C) displayed a threshold effect with a maximum at 23 cm/s, but this effect was absent at high temperature (31.1C) where QY increased linearly with flow to 43 cm/s. Our results indicate the potential for threshold effects of flow on growth of Porites sp. in the field, and demonstrate a threshold effect of flow on photophysiology at ambient temperature in the flume. Thus, our results may provide a means to reconcile previous inconsistencies in the effect of flow on corals.