Baseline shifts in coral skeletal oxygen isotopic composition: a signature of symbiont shuffling?

TitleBaseline shifts in coral skeletal oxygen isotopic composition: a signature of symbiont shuffling?
Publication TypeJournal Article
Year of Publication2013
AuthorsCarilli JE, Charles CD, Garren M, McField M, Norris RD
JournalCoral Reefs
Date Published2013/06
Type of ArticleArticle
ISBN Number0722-4028
Accession NumberWOS:000318567900028
Keywordsalgal symbioses; biological carbonates; calcification; caribbean corals; Climate variability; coral; Coral biomineralization; el-nino; functional-significance; Isotopic records; marine carbonates; montastraea-annularis; scleractinian corals; sea-surface temperature; Skeletal geochemistry; Symbiodinium

Decades-long records of the stable isotopic composition of coral skeletal cores were analyzed from four sites on the Mesoamerican Reef. Two of the sites exhibited baseline shifts in oxygen isotopic composition after known coral bleaching events. Changes in pH at the calcification site caused by a change in the associated symbiont community are invoked to explain the observed shift in the isotopic composition. To test the hypothesis that changes in symbiont clade could affect skeletal chemistry, additional coral samples were collected from Belize for paired Symbiodinium identification and skeletal stable isotopic analysis. We found some evidence that skeletal stable isotopic composition may be affected by symbiont clade and suggest this is an important topic for future investigation. If different Symbiodinium clades leave consistent signatures in skeletal geochemical composition, the signature will provide a method to quantify past symbiont shuffling events, important for understanding how corals are likely to respond to climate change.