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Heat Attenuation and Nutrient Delivery by Localized Upwelling Avoided Coral Bleaching Mortality in Northern Galapagos During 2015/2016 ENSO
Coral Reefs
  • Bernhard Riegl, Nova Southeastern University
  • Peter W. Glynn, University of Miami
  • Stuart Banks, Conservation International - Ecuador
  • Inti Keith, Charles Darwin Research Station - Galapagos, Ecuador
  • Fernando Rivera, Instituto Nazca de Investigaciones Marinas - Santa Elena, Ecuador
  • Mariana Vera-Zambrano, Conservation International - Galapagos, Ecuador
  • Cecilia D'Angelo, Coral Reef Laboratory - Southampton, United Kingdom
  • Joerg Wiedenmann, Coral Reef Laboratory - Southampton, United Kingdom
ORCID
0000-0002-6003-9324
ResearcherID
F-8807-2011
Document Type
Article
Publication Date
8-1-2019
Keywords
  • Coral bleaching,
  • ENSO,
  • Galapagos,
  • Upwelling,
  • Nutrients,
  • Reef resilience
Abstract

Despite a very strong El Niño Southern Oscillation in 2015/2016, no coral mortality associated with bleaching was observed at the northern Galapagos (Ecuador) Islands of Darwin and Wolf. From March 2016 to March 2018, coral cover and health as well as water chemistry (NO3− and PO43−) and temperature were recorded. A marked heat anomaly reached 30 °C at Wolf in February 2016, but peak temperatures were attenuated after 2 d by a 4 °C drop. Temperature patterns at three depths (10, 15, and 20 m) and a subsequent and persistent phytoplankton bloom suggest topographically driven upwelling as the source of colder water and dissolved inorganic nutrients—both of which helped corals endure the heating episode. Consequently, no mortality and only partial bleaching were recorded in March 2016. Partially bleached corals contained numerous healthy zooxanthellae in deeper tissue layers. A continuous temperature record from 2012 to 2014 suggests that such upwelling events are common, inducing temperature fluctuations of up to 6 °C within 24 h during the observation period. Events at Wolf in 2016 suggest local upwelling reduced coral stress by relieving heat and by delivering nutrients required by corals to retain their regular temperature tolerance.

DOI
10.1007/s00338-019-01787-8
Comments

©Springer-Verlag GmbH Germany, part of Springer Nature 2019

Additional Comments
Eastern Tropical Pacific Seascape Transition Phase grant #: CI CI240-560; NSF grant #: OCE-1447306, OCE-9314798; NERC grant #: NE/K00641X/1; European Research Council prgoram #: FP/2007-2013/ERC Grant Agreement No. 311179
Citation Information
Bernhard Riegl, Peter W. Glynn, Stuart Banks, Inti Keith, et al.. "Heat Attenuation and Nutrient Delivery by Localized Upwelling Avoided Coral Bleaching Mortality in Northern Galapagos During 2015/2016 ENSO" Coral Reefs Vol. 38 Iss. 4 (2019) p. 773 - 785 ISSN: 0722-4028
Available at: http://works.bepress.com/bernhard-riegl/219/