| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | June 7, 2019 |
| Latest Amendment Date: | March 11, 2022 |
| Award Number: | 1935308 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Cynthia Suchman
csuchman@nsf.gov (703)292-2092 OCE Division Of Ocean Sciences GEO Directorate For Geosciences |
| Start Date: | June 15, 2019 |
| End Date: | December 31, 2022 (Estimated) |
| Total Intended Award Amount: | $76,075.00 |
| Total Awarded Amount to Date: | $76,075.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
321-A INGRAM HALL AUBURN AL US 36849-0001 (334)844-4438 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Auburn AL US 36849-0001 |
| Primary Place of Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | BIOLOGICAL OCEANOGRAPHY |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Coral reefs provide strong economic and ecological benefits, yet they are declining worldwide largely due to extreme heat events that cause bleaching, a disturbance of the essential relationship between the algae that live inside the coral and the coral. There is currently a mass coral bleaching event in Moorea, French Polynesia where up to 90% of corals show some level of bleaching in response to heat stress. This location is ideal to study adaptation and acclimation thanks to the facilities and sampling of the Moorea Coral Reef (MCR) Long Term Ecological Research (LTER) site. This project explores how strong natural disaster events shape genetic differences in populations through time. By using historical environmental data it may be possible to identify modifications of the genome linked to past bleaching events. This knowledge will help establish models to predict reef recovery after disturbance and will be useful for choosing colonies with the best chance of survival in restoration efforts. This project also investigates how the bleaching history of the parents impacts characteristics of the next generations, such as reproductive output, larval, survival and heat tolerance. This project will provide training and involvement in research for three senior PhD students and at least five undergraduates. Coral restoration efforts rely on understanding how corals might adapt to environmental stress.
The mass coral bleaching event currently occurring in French Polynesia (April 2019) offers an opportunity to test hypotheses regarding mechanisms of rapid response to large scale disturbances. This project investigates potential epigenetic and genetic mechanisms involved in either resisting stress or recovering from bleaching. The research leverages the Moorea Coral Reef (MCR) LTER, which integrates the high resolution oceanographic metrics and data on long-term community dynamics into the study of rapid adaptation of Acropora hyacinthus. Genetic and epigenetic signatures of a natural selection event (bleaching) are tracked in the field to test the impact of bleaching history on reproductive and carry-over effects in larval and juvenile corals. Both physiological and molecular methods, such as 2bRAD genotyping and reduced representation bisulfite sequencing, are employed to investigate correlations between phenotypes and genetic and epigenetic differences in the genome. This work explores associations between selection on genetic variation and epigenetic variation as well as the potential role of DNA methylation in phenotypic change across a generation in association with coral bleaching. In this era of global change, there is mounting evidence that rapid evolutionary processes are occurring at time scales relevant to ecological processes. Therefore, capitalizing on a system with rich long-term ecological data, such as that associated with the MCR LTER, is ideal to investigate mechanisms of rapid adaptation.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
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.
Marine heatwaves are occurring globally and can have large impacts on species that already live at the higher edge of their thermal limits. In 2019, a marine heatwave in Mo’orea French Polynesia caused coral bleaching, where the close symbiotic relationship between coral and algae breaks down, ultimately starving the coral and leading to mortality. Coral bleaching and the mass mortality of reef-building corals impacts coastal ecosystems and the humans that inhabit them in significant ways, such as reductions in biodiversity of species used as a primary food source, protection from storm damage, and tourism, to name a few. However, it remains unknown how coral reefs can rebound from significant disturbances, and how sensitive these ecosystems are to multiple disturbances back-to-back. Our work suggests that while there was a mass mortality event in Moorea, French Polynesia in 2019 that led to significant death of reef-building corals, there were some corals that persisted, either through recovery of symbionts following the marine heatwave, or resistance to the heatwave altogether. We found that resistant colonies hosted a different symbiont type and fed more on particulate organic matter from offshore water, which could have contributed to their high resistance to bleaching. Alternatively, we also found colonies that recovered completely from bleaching, and these corals hosted a different symbiont, and coral bleaching depleted their energy reserves severely to the point where they could not make as many eggs and sperm for the next generation. We also found that while this species experienced a population bottleneck after the marine heatwave, this mortality may have opened physical space that allowed immigration of corals from neighboring islands, which increased genetic diversity in the population above what it was initially. Finally, we have found that there are legacy effects of this marine heatwave evident in the epigenome of corals. Taken together, our work suggests that there are resilience mechanisms in play within this ecosystem, so long as suitable habitat remains for coral recruitment, and there is sufficient time for adults that survived the marine heatwave to recover their reproductive capacity. Our project thus provides a better understanding of the dynamics of reef resilience following a marine heatwave.
Last Modified: 03/13/2023
Modified by: Marie Strader
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