SEMINAR: MBF 602 student seminar series speaker- Remy Okazaki Friday October 29, 2010 4p s/a seminar room

["Sidney Hartley" <shartley@rsmas.miami.edu>]

 

 

 

Calcification of corals from the stress-tolerant genus Solenastrea in a reciprocal transplant study

Stress-tolerant corals and their marginal habitats such as Florida Bay are ideal for studying calcification responses to the dual stressors of warming and ocean acidification.  Despite experiencing diurnal and seasonal variations in pCO₂ of 100s of ppm in addition to extremes in temperature, light, and salinity, corals of the genus Solenastrea appear to thrive in Florida Bay.  This transplant experiment investigated how the growth of Solenastrea spp. compares between normal (open marine) and marginal environments.  Specimens of Solenastrea hyades were reciprocally transplanted between Peterson Keys (Florida Bay) and Triangles patch reef.  At each site the specimens were incubated in situ to measure calcification under elevated CO₂ and normal conditions.  Two-way ANOVA analyses indicated all corals responded to pCO₂ in a similar manner with 16-33% calcification declines per unit saturation state (Ω_arag) (95% CI) (F_coral1,76=2.71, p=0.10; F_Envi1,76=1.12, p=0.29; F_Int1,76=0.01, p=0.91).  These responses corroborate the generalized response of 28% decline per unit Ω_arag observed in most laboratory studies.  Calcification rates however were higher for the specimens from Triangles than Florida Bay (4.8 ± 3.3 vs 2.8 ± 1.8 mean±SD mmol CaCO₃ m^-2 h^-1; Two-way ANOVA F_1,99=23.40, p<0.001).  These results indicate that while corals can mediate their overall calcification rates, they cannot control how their calcification responds to pCO₂.  Despite their higher growth rates, Triangles corals experienced a higher amount of bleaching and mortality in 2010.  These qualitative observations suggest these corals face a tradeoff between stress-tolerance and calcification rates.  Identifying whether and what proportion of corals best cope with this tradeoff is a priority for reef conservation given the rapid and continuous increases in atmospheric pCO₂.

 

 

 

 

Remy Okazaki

B.S. 2005 – University of Utah

Entered Ph.D. program Fall 2006

 

Advisors:

Chris Langdon

Peter Swart