Award: OCE-1041270

Award Title: RUI: Ocean Acidification- Category 1- The effects of ocean acidification on the organismic biology and community ecology of corals, calcified algae, and coral reefs
Funding Source: NSF Division of Ocean Sciences (NSF OCE)
Program Manager: David L. Garrison

Outcomes Report

This project focused on the effects of ocean acidification (OA) on coral reefs around Moorea, French Polynesia, where the United States operates the Moorea Coral Reef, Long-Term Ecological Research site (http://mcr.lternet.edu). OA describes the acidification of seawater by the dissolution of atmospheric carbon dioxide (pCO2) of human origin, and the changes in seawater chemistry threaten the ability of calcified organism to mineralize. These threats affect marine organisms throughout the world, but the challenges to tropical coral reefs are acute as the biological engineers of these systems – corals and calcified algae – rely on high rates of mineralization to build massive, wave-resistant structures providing goods and services to countless organisms, including humans. Together with threats to coral reefs created by rising seawater temperature and local-scale disturbances, some researchers have suggested the future of coral reefs is threatened. To address these issues, we embarked on a 4-year program to answer four questions: (1) what are the shapes of the relationships between pCO2 and the ability of corals and calcified algae to calcify, (2) how are the shapes of these relationships affected by light and temperature, (3) are the effects of pCO2 on calcification by corals and calcified algae affected by food and nutrients, and (4) how can results from small experiments with individual corals and calcified algae be summed to understand how coral reef ecosystems will change in a more acidic future? In terms of intellectual merit, we have published > 15 research papers (http://www.bco-dmo.org/project/2242) and 9 graduate theses in the course of addressing the project goals. Together, these papers contribute to the field in three important ways. First, our work has confirmed the magnitude of the threat posed to corals and calcified algae by OA, but we have consistently found that at least a few species are resistant to the extent of OA that is expected to occur on a centurial scale, potentially because they are capable of utilizing bicarbonate to support calcification in the light. Resistance to OA appears to be an intrinsic feature of these taxa, as we obtained similar results in Hawaii and Okinawa; in contrast, susceptibility to OA is slightly accentuated in fast growing corals and calcified algae. Together, these results provide a basis to understand which corals and calcified algae are likely to populate reefs of the future (i.e., the "winners"), and which are likely to become rare (i.e., the losers). Second, for corals and calcified algae that are negatively affected by OA, we have shown that their responses are linear without "tipping points". This is an important discovery, for while it shows that OA will depress calcification, the effects are likely predictable and gradual. Finally, as our experiments matured, we progressed from organism-scale analyses in indoor tanks, to community-scale analyses in large outdoor flumes exposed to natural sunlight and realistic flow speeds. We created replicas of reef communities in these flumes, and matched the communities to those occurring in the lagoon and at 17 m depth, and incubated them at elevated pCO2. The results of these experiments underscore the negative effects of OA on calcification of whole reef communities, but they show that the most serious effects will be caused by dissolution of sediments and the reef framework itself. In terms of broader outreach, our project has contributed to answering a question of broad societal value: will coral reefs endure in a more acidic future? Our work suggests that coral reefs will persist on a centurial scale, although the species of corals and algae building the reefs will likely change, and dissolution of foundational reef rock will progressively weaken the underlying framework. In the course of answering this question, we have provided unique opportunities for US students (12 graduates, and 7 unde...
DatasetLatest Version DateCurrent State
Coral and algae calcification rates collected from the Richard B Gump Research Station during 2011 from Moorea, French Polynesia (MCR LTER project, OA_Corals project)2012-11-20Final no updates expected
Coral and algae calcification rates in varying carbonate regimes collected from the Richard B Gump Research Station during 2011, from Moorea, French Polynesia (MCR LTER project, OA_Corals project)2012-11-22Final no updates expected
Experimental results of effects of acidification on corals and calcified algae collected from the Richard B Gump Research Station during 2011, in French Polynesia (MCR LTER project, OA_Corals project)2012-12-03Final no updates expected
Experimental results of calcification rates of corals at variable pCO2 from the Richard B Gump Research Station, Moorea, French Polynesia in 2011 (MCR LTER project, OA_Corals project)2014-07-09Preliminary and in progress
Experimental results of calcification rates of algae at variable pCO2 concentrations from the Richard B Gump Research Station, Moorea, French Polynesia in 2011 (MCR LTER project, OA_Corals project)2015-03-21Preliminary and in progress
Carbonate chemistry parameters in flume study during the day from Richard B Gump Research Station - Moorea LTER, French Polynesia from 2013 (MCR LTER project, OA_Corals project)2014-11-04Final no updates expected
Calcification rates of communities and sediment in a flume from Richard B Gump Research Station - Moorea LTER, French Polynesia from 2013 (MCR LTER project, OA_Corals project)2014-11-04Final no updates expected
Percent of Montipora and Porites colonies competing in Moorea, French Polynesia during 2010 (OA Corals project)2016-03-07Final no updates expected
Linear growth of individual Montipora and Porites corals competing for space in Moorea, French Polynesia during 2010 (OA Corals project)2016-03-10Final no updates expected
Chemical and physical measurements in coral tanks from Moorea, French Polynesia in 2010 (OA Corals project)2016-03-10Final no updates expected
Calcification Rates and Biomass of 4 Coral Species, 2 Temperatures and 2 pCO2 Levels from Experiments at LTER site in Moorea, French Polynesia, 2011 (OA_Corals project)2016-04-04Final no updates expected
Tank seawater conditions from Coral/Temperature/pCO2 Experiments at LTER site in Moorea, French Polynesia, 2011 (OA_Corals project)2016-04-04Final no updates expected
Coral (Porites rus) calcification and chemistry data from outdoor flumes at the UCB Gump Research Station Moorea, French Polynesia in April and March of 20122020-11-30Final no updates expected
Calcification data from outdoor flume experiments with coral Acropora hyacinthus at the UCB Gump Research Station Moorea, French Polynesia in September and October of 20122020-11-17Final no updates expected
Calcification and carbonate chemistry from outdoor flume experiments with corals at locations in Moorea, Okinawa, and Hawaii from 2011 to 20132020-12-02Data not available
Carbonate chemistry from outdoor flume experiments with coral Acropora hyacinthus at the UCB Gump Research Station Moorea, French Polynesia in September and October of 20122020-11-17Final no updates expected
2019-02-01Data not available
2019-02-01Data not available
2020-12-02Data not available
2020-12-02Preliminary and in progress
2020-12-02Preliminary and in progress
2020-12-02Preliminary and in progress
2020-12-02Data not available
2020-12-02Data not available
Coral weight from a study of year-long effects of high pCO2 on the community structure of a tropical fore reef assembled in outdoor flumes in Moorea, French Polynesia from 2017 to 20182024-04-09Final no updates expected
Coral area from a study of year-long effects of high pCO2 on the community structure of a tropical fore reef assembled in outdoor flumes in Moorea, French Polynesia from 2017 to 20182024-04-09Final no updates expected

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People

Principal Investigator: Robert C. Carpenter (The University Corporation, Northridge)

Co-Principal Investigator: Peter J Edmunds