Andrew Miller

Honors in Marine Biology

Majors: Marine Biology

Supervisor: Alina Szmant, Biology and Marine Biology

The Effects of Elevated Seawater Temperatures on the Development, Survivorship and Settlement of the Larvae of the Caribbean Reef-Building coral, Montastraea faveolata

Rising seawater temperatures in the Caribbean due to global warming have led to a growing concern over the effects of elevated temperatures on coral reef ecosystems. This experiment examined the effects of elevated seawater temperatures on the development, survivorship and settlement of the early life stages of an important Caribbean reef-building coral, Montastraea faveolata. M. faveolata spawns when temperatures are highest in the late summer. Following spawning, embryos and larvae were incubated in three temperature treatments, 28 ºC, 30 ºC and 31.5 ºC for the duration of embryogenesis and larval development; every ca.12 hours, survivorship was examined at each temperature. Embryo and larval samples were fixed from each treatment over a 110 hour time course and examined for development stage analysis. Once competent to settle, larvae were placed in settlement assays to examine settlement over the temperature range. Larvae in the elevated temperature treatments (30 ºC and 31.5 ºC) developed faster and experienced a greater percentage of developmental abnormalities relative to larvae at 28 ºC. The embryos/larvae in the elevated temperature treatments also suffered a higher mortality over the time course. Larvae in all three temperature treatments exhibited poor settlement, with no difference among temperatures. Overall, elevated temperature was observed to have a negative effect on the development and survivorship of larvae from the reef-building coral Montastraea faveolata. Temperature was observed to have little to no effect on the settlement of larvae of M. faveolata. These results indicate that elevated seawater temperatures will reduce the recovery potential of M. faveolata in endangered reef habitats.