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Award Detail

Doing Business As Name:Stanford University
  • Stephen R Palumbi
  • (831) 655-6214
Award Date:06/26/2015
Estimated Total Award Amount: $ 185,919
Funds Obligated to Date: $ 185,919
  • FY 2015=$185,919
Start Date:07/01/2015
End Date:06/30/2017
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:RAPID: Ecological, evolutionary and physiological responses of corals to a mass bleaching event in American Samoa
Federal Award ID Number:1547921
DUNS ID:009214214
Parent DUNS ID:009214214

Awardee Location

Street:450 Jane Stanford Way
Awardee Cong. District:18

Primary Place of Performance

Organization Name:Hopkins Marine Station
Street:120 Ocean View Blvd
City:Pacific Grove
County:Pacific Grove
Cong. District:20

Abstract at Time of Award

The strongest coral bleaching event in nearly 20 years began in American Samoa in January 2015. Coral bleaching occurs when ocean water temperatures exceed a coral's normal heat tolerance. But bleaching events usually show an unexplained pattern - colonies next to one another can show very different levels of bleaching - from pure white to the normal tan color of a healthy coral. The investigators have observed this pattern among 280 corals on reefs in American Samoa that have been studied for years. This system will be used to test four major hypotheses about what causes some corals to bleach and some not: differences in 1) species, 2) the temperature the corals experienced, 3) the symbiont they harbor, and 4) the genotype of the coral host. In addition, the investigators will return to American Samoa at regular intervals to measure the rate of recovery of each coral colony and conduct the same tests as above for recovery rate. The stark-white reefscapes left behind by bleaching events are one of the most common signals of increased ocean warming. This work will take advantage of years of prior study and the advent of a coral bleaching event to understand the rules for survival on reefs. The reefs of American Samoa began showing a major bleaching event starting in January 2015, including 62 corals that have been intensively studied for coral thermal resistance, field temperatures, and symbiont type. In April 2015 the investigators monitored bleaching status of these and additional corals, totaling 280 corals from four species, and uncovered marked variation in bleaching extent within and between species and within and between reef regions. The team will test the relative importance of microclimate to bleaching state by examining records of approximately 50 temperature loggers in place since before the bleaching event. They will test the influence of symbiont type and host gene expression profiles by examining samples of 60 colonies taken at four time points after bleaching. The investigators will also examine the full suite of 280 corals for genetic variation to estimate the relationship between bleaching state, recovery rate and genetic polymorphism. These data will be used to test micro-climate, symbiont, and coral genetics as determinants of bleaching and bleaching recovery. Because the investigators have samples from these 280 colonies before bleaching mortality, this study will provide the first estimate for the evolutionary impact of a bleaching event on coral populations.

Publications Produced as a Result of this Research

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Thomas, L., Rose, N.H., Bay, R.A., López, E.H., Morikawa, M.K., Ruiz-Jones, L. Palumbi, S.R. "Mechanisms of Thermal Tolerance in Reef-Building Corals across a Fine-Grained Environmental Mosaic: Lessons from Ofu, American Samoa." Frontiers in Marine Science, v.4, 2018, p.434.. doi: 

Gold, Z. Palumbi, S. "Long-term growth rates and effects of bleaching in Acropora hyacinthus" Coral Reefs, v.37, 2018, p.267. doi: 

Thomas, Luke Palumbi, Stephen "The genomics of coral bleaching recovery" Proceedings of the Royal Society B, v.284, 2017, p.20171790. doi: 

Project Outcomes Report


This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

As climate change progresses and extreme temperature events increase in frequency, rates of disturbance may soon outpace the capacity of certain species of reef-building coral to recover. This may lead to dramatic shifts in community composition and ecosystem function.

However, some coral species include individual colonies living well in high-heat environments, and these have been proposed as important nursery stock for future restoration. But heat-tolerance could be due to adjustable physiology or the microbiome or different symbionts, so whether colonies retain their tolerance and resist bleaching when moved into nurseries remains unclear. We showed that colonies from heat-tolerant parent corals showed two-fold to three-fold less bleaching, compared with corals from less heat-tolerant parent species, even after 8 months of acclimatization in a common garden. These results suggest that selecting coral colonies that can withstand warm ocean conditions can aid the development of nurseries for climate-resilient corals.

In addition, understanding variation in rates of bleaching recovery among species and how that translates to resilience to recurrent bleaching is fundamental to predicting the impacts of increasing disturbances on coral reefs globally. We tracked the response of two heat sensitive species in the genus Acroporato repeated bleaching events during the austral summers of 2015 and 2017. Our data uncovered unexpected variation in a group of corals thought generally to be heat-sensitive, and therefore paint a more optimistic view of the future health of coral reef ecosystems against a backdrop of increasing thermal disturbances.

Last Modified: 05/06/2019
Modified by: Stephen R Palumbi

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