Kuffner, I. B., U.S. Geological Survey, St. Petersburg, FL, USA, ikuffner@usgs.gov
Andersson, A. J., Bermuda Institute of Ocean Sciences, St. George's, Bermuda, andreas.andersson@bios.edu
Jokiel, P. L., Hawaii Institute of Marine Biology, Kaneohe, HI, USA, jokiel@hawaii.edu
Rodgers, K. S., Hawaii Institute of Marine Biology, Kaneohe, HI, USA, kuuleir@hawaii.edu
Mackenzie, F. T., University of Hawaii, Department of Oceanography, Honolulu, HI, USA, fredm@soest.hawaii.edu

OCEAN ACIDIFICATION AND CORAL REEFS: WILL CHANGES IN COMMUNITY STRUCTURE OVERWHELM SUB-LETHAL DECREASES IN CALCIFICATION RATES?

Empirical studies predict that calcification rates of reef organisms will decrease within the next century due to ocean acidification (OA). The effects of OA on ecological processes, such as recruitment and competition for space, are relatively unstudied. Theoretically, calcifying organisms will be less competitive in a high-pCO2 world because the rate at which they build their skeletons to occupy space will be reduced. We conducted a nine-month experiment to measure the effects of OA on sessile community development. Mesocosms continually received non-filtered seawater from the adjacent Hawaiian reef flat, with three at ambient seawater conditions, and three with pCO2 levels exceeding ambient daytime conditions by 365 (± 130 s.d.) µatm. Recruitment rate and space occupation by crustose coralline algae were severely inhibited in treatment mesocosms, with a 78% and 92% reduction, respectively, compared to control mesocosms. We propose that accounting for the replacement of calcifying organisms by those that do not calcify, rather than simply extrapolating measurements of decreased calcification rates, will be necessary in predicting future reef accretion rates in the face of OA.

Oral presentation

Presentation is given by student: No
Session #:144
Date: 03-07-2008
Time: 08:00

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