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Award Detail

Doing Business As Name:University of California-Los Angeles
  • Robert Eagle
  • (310) 206-3531
  • Aradhna Tripati
Award Date:07/01/2014
Estimated Total Award Amount: $ 270,587
Funds Obligated to Date: $ 270,587
  • FY 2014=$270,587
Start Date:09/01/2014
End Date:08/31/2018
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:Collaborative Research: A combined boron isotope, pH microelectrode and pH-sensitive dye approach to constraining acid/base chemistry in the calcifying fluids of corals
Federal Award ID Number:1437166
DUNS ID:092530369
Parent DUNS ID:071549000
Program Officer:
  • Daniel J. Thornhill
  • (703) 292-8143

Awardee Location

Street:10889 Wilshire Boulevard
County:Los Angeles
Awardee Cong. District:33

Primary Place of Performance

Organization Name:University of California-Los Angeles
Street:595 Charles E. Young Dr. East
City:Los Angeles
County:Los Angeles
Cong. District:33

Abstract at Time of Award

The anthropogenic elevation of atmospheric CO2 is causing the oceans to become more acidic, which may make it more challenging for corals to build their skeletons and, ultimately, entire reef structures. How corals respond to future ocean acidification will largely depend on how the pH of the internal fluid from which they produce their skeletons-their so-called calcifying fluid-is impacted by the surrounding seawater. It is therefore essential that current methods are refined to accurately measure the pH of corals' calcifying fluids in order to understand and, ideally, predict their responses to CO2-induced ocean acidification. In this project, a three-pronged approach to measure calcifying fluid pH within three species of reef-forming corals will be used to assess how their calcifying fluid pH responds to experimentally induced ocean acidification. This research will improve our understanding of corals' responses to ocean acidification and thus has the potential to inform the decisions of policy makers and legislators seeking to mitigate the deleterious effects of rising atmospheric CO2 on marine ecosystems. The work will support the development of three early career scientists, a postdoctoral fellow, graduate students, and undergraduate researcher assistants-several of whom are from underrepresented groups in the earth and ocean sciences. Results will be widely disseminated through publications, conference presentations, the PIs' websites, an educational film, coursework, and outreach activities at area schools, museums, and science centers. Corals and other types of marine calcifiers are thought to begin the mineralization of their calcium carbonate skeletons by actively elevating pH of their calcifying fluid, thereby converting bicarbonate ions (comprising ~90% of seawater dissolved inorganic carbon) to carbonate ions, the form of carbon used in calcification. This project will compare the combined boron isotope, pH microelectrode, and pH-sensitive dye approach to measure the calcifying fluid pH of three species of scleractinian corals, and to assess how their calcifying fluid pH (a primary factor controlling their calcification) responds to experimentally induced ocean acidification. As a result this multi-pronged approach to measuring calcifying fluid pH of the same coral species under equivalent culturing conditions will permit the first systematic cross-examination of the validity of these independent approaches. The combined approach will also yield values of calcifying fluid pH with uncertainties that can be quantified via inter-comparison and statistical treatment of these independent measurements. Importantly, this multi-pronged approach will be used on three coral species that due to differences in the carbonate chemistry of their native waters possess differing capacities for proton regulation at their site of calcification; a deep, cold-water coral (strong proton-pumper); a shallow, temperate coral (moderate proton-pumper); and a shallow, tropical coral (weak proton-pumper). Target outcomes of this research include (1) cross-examination of the validity of three independent approaches to estimating coral calcifying fluid pH, (2) quantification of uncertainty associated with the three approaches to estimating coral calcifying fluid pH, (3) advancement of our mechanistic understanding of coral calcification, (4) exploration of the mechanism by which ocean acidification impacts coral calcification, (5) elucidation why corals exhibit such varied responses to ocean acidification, (6) identification of coral types most vulnerable to ocean acidification, (7) exploration of so-called "vital effects" that limit the use of corals in paleoceanographic reconstructions, and (8) quantitative constraint of existing models of coral biomineralization.

Publications Produced as a Result of this Research

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Sutton J, Liu Y-W, Ries J., Guillermic M., Ponzevera E., Eagle R. "?11B as a monitor of calcification site pH in divergent marine calcifying organisms." Biogeosciences, v.15, 2018, p.1447.

Liu Y-W, Eagle R, Aciego S, Gilmore R, Ries J. "Coccolithophore vesicle pH homeostasis confers limited resilience to ocean acidification." Nature Communications, v., 2018, p..

Sutton J, Eagle R., Ponzevera E, Rouxel O, and Ries J. "?11B MC-ICPMS measurements from marine carbonates with a batch and column chemistry approaches." Biogeosciences Discussions, v., 2017, p..

Kimball J, Tripati R, Dunbar R. "Distinct carbonate ?clumped? isotope signatures in aragonite scleractinian and calcitic gorgonian deep-sea corals" Biogeosciences, v., 2016, p..

Tripati AK, Hill, PM, Eagle RA, Mosenfelder JL, Tang J, Henry D, Schauble EA, Eiler JM, Zeebe RE, Uchikawa J, Coplen T, Ries JB and Henry D. "Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition" Geochimica et Cosmochimica Acta, v.166, 2015, p.344.

Liu, Y-W, DeCorte, I, Guillermic, M, Misra, S, Ries, J, Eagle, R, "Diverse responses of calcifying fluid pH in coral and other invertebrates to acidified conditions" Geochimica et Cosmochimica Acta, v., 2017, p..

Doss W, Marchitto T., Eagle R., Rashid H., Tripati A. ". Insight into temperature and saturation state controls on benthic foraminiferal Li/Ca based on downcore paired B/Ca measurements and coretop compilation." Geochimica et Cosmochimica Acta., v., 2018, p.. doi: 

? Tripati AK, Hill, PM, Eagle RA, Mosenfelder JL, Tang J, Henry D, Schauble EA, Eiler JM, Zeebe RE, Uchikawa J, Coplen T, Ries JB and Henry D. "Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition." Geochimica et Cosmochimica Acta, v.166, 2015, p.344.

Tripati AK, Hill, PM, Eagle RA, Mosenfelder JL, Tang J, Henry D, Schauble EA, Eiler JM, Zeebe RE, Uchikawa J, Coplen T, Ries JB and Henry D. "Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition" Geochimica et Cosmochimica Acta, v.166, 2015, p.344.

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.

Many of the major coral reef systems on our planet have seen massive bleaching events in recent years. Bleaching refers to the when the symbiotic algae that lives within the coral tissues leaves the coral under conditions of stress. Whilst some corals and reefs can recover from bleaching, in many instances it leads to coral death and the severity of bleaching events and the fact that they are occurring in successive years leaves many reefs little chance to recover, and seems likely to lead to widespread reef collapse. Scientists widely believe the principle driver of future reef collapse will be increasing ocean temperatures, as coral bleaching events are typically associated with temperature spikes in reef waters and in controlled experiments reef building corals and their algae are typically very sensitive to temperature change. However, that is not the whole picture as other factors such as diseases affecting corals and secondary effects of carbon dioxide dissolving into the oceans – termed ocean acidification – could be at play. While corals negative response to excessive heat is clear, coral response to CO2 induced ocean acidification is more complex, with widespread differences in sensitivity between species. We now have a relatively large amount of information on coral species response to environmental change including temperature and acidity, but what we lack is information on the underlying mechanisms for species-specific differences in responses. One hypothesis is that there are differences in the ability of different organisms to regulate the chemistry of the fluids that are used to form their shells and skeletons inside their tissues. By knowing the mechanisms of coral resilience or sensitivity to environmental change, we can improve conservation efforts and predictions for the future of ocean ecosystems.

In this NSF-funded project, a team of scientists including international collaborators sought to explore the underlying mechanisms behind different species of corals resilience or susceptibility to ocean temperature and acidity change. The species studied included several species of warm water symbiont-bearing warm water corals, and a cold-water deep-sea dwelling coral that lacks symbionts. Using a unique combination of techniques drawn from both cell biology and geochemistry that allow us to probe the internal acidity of the fluids from which corals produce their shells and skeletons. we first confirmed the observation that diverse species of corals actively regulated the acidity of their internal fluids compared to seawater, in order to facilitate skeleton production.

Secondly, we found a new relationship between symbiont activity and coral resilience to CO2 induced ocean acidification. Specifically corals grown at temperatures optimal for symbiont activity are not only resilient to high CO2 but in many cases grow faster, presumably as the symbiont utilizes the CO2 to produce energy more efficiently through photosynthesis. When corals are grown at a temperature that impaired symbiont activity, they are found to lose internal acidity control and then become more sensitive to ocean acidification. These effects were not seen in the non-symbiont bearing deep-sea coral where increasing temperature has the opposite effect, namely increasing growth. Therefore symbiont health is directly linked coral sensitivity to ocean acidification in a surprising way. In total the results confirm temperature rather than ocean acidification is the dominant risk to surface water corals. 

During the course of this project the project co-investigator Robert Eagle became a faculty fellow in the Center for Diverse Leadership in Science, a new entity based in the Institute of the Environment and Sustainability at UCLA. The aim of this entity is to provide multi-tier mentorship to students and researchers including those from groups underrepresented in the sciences and help individual faculty develop their skills in inclusion and become leaders in inclusive excellence. Several undergraduate students including minorities that are heavily under-represented in oceanography were recruited to do research supported by this project during the course of this grant, in line with the goals of this new center.

Results were also included in undergraduate and graduate classes at UCLA taught by the PIs, including a GE class to 150 students taught for the past two years (Env Sci M10) Introduction to Environmental Science, an upper division course taught to 35 students taught for the past two years (AOS 107) Biological Oceanography, and a graduate course (AOS 235) on climate change impacts on the ocean. It was also use to create outreach activities for K-12 and community outreach, including at Central High School, an under-resourced school supporting Native American and Latinx students in downtown Los Angeles. The work was also highlighted in outreach to Latinx and African-American girls that are age 6-8 through Project Scientist.


Last Modified: 02/24/2019
Modified by: Robert Eagle

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