What doesn’t kill you makes you stronger: Galapagos reef recovery.

Hello again! I really hope corals have started to “grow” on you guys too. Corals have had it rough over the years but in the words of Gloria Gaynor, “[they] will survive.”

The Galapagos sits at the intersection of five major ocean currents, resulting in a rapidly changing climate island to island and season to season. [2] As I stated in my previous post, the 1982-1983 El Nino decimated the coral population near the Galapagos Islands. It caused over 95% of the corals to bleach, and recovery has been a long uphill battle since. [1] Despite the threat from another strong El Nino in 1997-1998, Galapagos reefs managed to continue to survive. [2]

The rapid warming of the ocean waters is not allowing enough time for corals to naturally evolve tolerance as they possess a poor genetic ability to adapt to such stresses in their long lifetimes. [1] A Satellite Bleaching Alert Level 2 (signifying widespread coral bleaching and mortality) was issued by NOAA for areas including the Galapagos Islands. However, recent observations by scientists suggest that the influence of large-scale thermal stress may have been overestimated. [4] In the summer of 2012 a team of researchers surveyed the corals of 8 islands and recorded coral recovery as well as factors that were significant in making corals resilient to environmental disturbances. [2] They found promising signs of recovery for the Galapagos reefs, a glimmer of hope in wake of our current situation, the third ever global coral bleaching event.

Three northern islands, Marchena, Wolf and Darwin, showed the most signs of recovery. [2] A research paper done in 2009 attributes the intact coral frameworks at Darwin Island to relatively low levels of bio erosion. This has permitted the surviving coral patches to regenerate as well as allowed the settlement of coral recruits. [3] The abundance of colonies with dead patches decreased to 93.8% in 2000 to 5.7% in 2007, a dramatic change by anyone’s standards. [3] It is predicted that a full recovery would take centuries, but it is in progress. [3]

The amount of coral bleaching that takes place also may depend on the distribution of coral species in the area. Patches of P. stellate have been found within the Devil’s Crown in the Galapagos Islands. Their recovery can be attributed to the settlement of larvae from upstream source populations. [5] Studies have shown that Psammocora spp. especially have exhibited adaptive characteristics that facilitate recovery: “(1) relative resistance to bleaching/mortality, especially below 10–12 m depth, (2) persistence of surviving deep source populations that can potentially promote recruitment into decimated shallow reef habitats, (3) prolonged seasonal reproductive periods and high fecundities, (4) asexual reproduction.” [5] These adaptations have allowed these colonies to experience less bleaching, minimal mortality, and faster recovery rates. [5]

These studies show that there is hope for the Galapagos coral reefs, despite the tremendous stresses they’ve been put through. Hopefully we can continue to watch as they defy odds and (very) slowly return to their former glory.

Sources:

[1] “How Global Warming Is Driving Mass Coral Bleaching.” Skeptical Science. N.p., 23 Sept. 2015. Web. <https://www.skepticalscience.com/coral-bleaching.htm>.

[2] Smith, Julian. “Threatened Galapagos Coral May Predict the Future of Reefs Worldwide.” Mongabay Environmental News. N.p., 07 Nov. 2012. Web. <http://news.mongabay.com/2012/11/threatened-galapagos-coral-may-predict-the-future-of-reefs-worldwide/>.

[3] Glynn, Peter W., et al. “Coral reef recovery in the Galápagos Islands: the northernmost islands (Darwin and Wenman).” Coral Reefs 34.2 (2015): 421-436.

[4] “2014-16 Bleaching Event Continues: June 2015 Update.” Coral Reef Watch. NOAA Satellite and Information Service, 2 June 2015. Web. <http://coralreefwatch.noaa.gov/satellite/analyses_guidance/global_bleaching_update_20150602.php>.

[5] Glynn, Peter W., et al. “Reef coral reproduction in the equatorial eastern Pacific: Costa Rica, Panamá, and the Galápagos Islands (Ecuador). VII. Siderastreidae, Psammocora stellata and Psammocora profundacella.” Marine biology 159.9 (2012): 1917-1932.