Marine & Environmental Sciences Faculty Articles

Heat Attenuation and Nutrient Delivery by Localized Upwelling Avoided Coral Bleaching Mortality in Northern Galapagos During 2015/2016 ENSO

ORCID

0000-0002-6003-9324

ResearcherID

F-8807-2011

Document Type

Article

Publication Title

Coral Reefs

ISSN

0722-4028

Publication Date

8-2019

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

Volume

38

Issue

4

First Page

773

Last Page

785

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

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