Kiritimati's reefs are mostly dead
On October 8th, 2015 NOAA declared that the world's 3rd ever global coral bleaching event was underway. Our field site, Kiritimati (Christmas) atoll in the central equatorial Pacific (northern Line Islands) sat at the epicentre of the thermal stress for nine straight months. This resulted in approximately 80% coral death as of March 2016.
In March 2016 the Baum Lab team completed our 11th expedition to Kiritimati. Led by PhD student Danielle Claar, the team documented the impacts from the massive El Niño.
Our sites are located along the 10 meter isobath, and are comprised primarily of a mixed scleractinian coral community composition of Porites, Montipora, Hydnophora, Favia, Favites, Platygyra, Montastrea, Pocillopora and several other less abundant hard corals (as well as leather corals and zoanthids).
In March 2016, coral death was approximately 80% and coral bleaching was approximately 15% overall (at 10m depth). The most impacted taxa on Kiritimati are Acropora, Montipora, Fungia, Pocillopora, Favids (i.e. Favia matthai, Favites halicora) and all soft corals. Some species such as Pavona, Favites pentagona, Platygyra and Hydnophora fared a bit better with approximately half still alive (does not indicate 100% healthy). Porites fared the best with some colonies that even appeared to be completely healthy, however, most of the colonies were bleaching and were starting to have tissue death.
Although we observed high percentages of coral death at all of our 15 surveyed sites, there was a small variation among sites.
We are now focusing on processing and sequencing all of our samples from all of the field seasons that the lab conducted around this El Niño. We are looking forward to sharing our results with you in the near future.
We will be conducting additional field seasons in the following summers to document the recovery of Kiritimati's reefs.
UPDATE: The team returned to Kiritimati in November. Coral death was up to 90% and macroalgae had established itself in pace of the coral. The structure of the reef was still intact but that is expected to degrade as the island gets hit with winter storm waves from the Northern Hemishpere. The team deployed coral recruitment tiles to document the reef's recovery.
Contact Julia (baum 'at' uvic.ca) or Danielle (dclaar 'at' uvic.ca) for more information. For more information about our fieldwork on Kiritimati: kiritimati.weebly.com/
Follow us on Twitter: @baumlab and @ClaarDanielle