A new study has found that La Niña-like conditions in the Pacific Ocean off the coast of Panamá were closely associated with an abrupt shutdown in coral reef growth that lasted 2,500 years. The study suggests that future changes in climate similar to those in the study could cause coral reefs to collapse in the future.
The study found cooler sea temperatures, greater precipitation and stronger upwelling — all indicators of La Niña-like conditions at the study site in Panama — during a period when coral reef accretion stopped in this region around 4,100 years ago. For the study, researchers traveled to Panama to collect a reef core, and then used the corals within the core to reconstruct what the environment was like as far back as 6,750 years ago.
“Investigating the long-term history of reefs and their geochemistry is something that is difficult to do in many places, so this was a unique opportunity to look at the relationship between reef growth and environment,” said Kim Cobb, an associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. “This study shows that there appears to have been environmental triggers for this well-documented reef collapse in Panama.”
The study was sponsored by the Geological Society of America, the American Museum of Natural History and the Smithsonian Institution’s Marine Science Network. The study is scheduled for publication on February 23 in the journal Nature Climate Change. The study was a collaboration with the Florida Institute of Technology, with Cobb’s lab providing an expertise in fossil coral analysis.
Climate change is the leading cause of coral-reef degradation. The global coral reef landscape is now characterized by declining coral cover, reduced growth and calcification, and slowdowns in reef accretion. The new study provides data to assist scientists in understanding how changes in the environment trigger long-term changes in coral reef growth and ecosystem function, which is a critical challenge to coral-reef conservation.
“Temperature was a key cause of reef collapse and modern temperatures are now within several degrees of the maximum these reefs experienced over their 6,750 year history,” said Lauren Toth, the study’s lead author, who was a graduate student at Florida Tech during the study. “It's possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”
For the study, the research team analyzed a 6,750-year-old coral core from Pacific Panamá. The team then reconstructed the coral’s past functions, such as growth and accretion (accumulation of layers of coral), and compared that to surrounding environmental conditions before, during and after the 2,500-year hiatus in vertical accretion.
“We saw evidence for a different climate regime during that time period,” Cobb said. “The geochemical signals were consistent with a period that is very cool and very wet, with very strong upwelling, which is more like a modern day La Niña event in this part of the Pacific.”
In Pacific Panamá, La Niña-like periods are characterized by a cold, wet climate with strong seasonal upwelling. Due to limited data at the site, the researchers cannot quantify the intensity of La Niña events during this time, but document that conditions similar to La Niña were present at this site during this time.
“These conditions would have been for quite an extended time, which suggests that the reef was quite sensitive to prolonged change in environmental conditions,” Cobb said. “So sensitive, in fact, that it stopped accreting over that period.”
Future climate change, similar to the changes during the hiatus in coral growth, could cause coral reefs to behave similarly, the study authors suggest, leading to another shutdown in reef development in the tropical eastern Pacific.
“We are in the midst of a major environmental change that will continue to stress corals over the coming decades, so the lesson from this study is that there are these systems such as coral reefs that are sensitive to environmental change and can go through this kind of wholesale collapse in response to these environmental changes,” Cobb said.
Future work will involve expanding the study to include additional locations throughout the tropical Pacific.
“A broad-scale perspective on long-term reef growth and environmental variability would allow us to better characterize the environmental thresholds leading to reef collapse and the conditions that facilitate survival,” Toth said. “A better understanding of the controls on reef development in the past will allow us to make better predictions about which reefs may be most vulnerable to climate change in the future."
This research is supported by a Graduate Student Research Grant from the Geological Society of America, the American Museum of Natural History’s Lerner-Gray Fund for Marine Research, and grants from the Smithsonian Institution’s Marine Science Network. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the sponsoring agencies.
CITATION: Lauren T. Toth, et al. "Climatic and biotic thresholds of coral-reef shutdown." (Nature Climate Change, February 2015) http://dx.doi.org/10.1038/nclimate2541
Georgia Institute of Technology
177 North Avenue
Atlanta, Georgia 30332-0181 USA
Media Relations Contacts: Brett Israel (@btiatl) (404-385-1933) (email@example.com) or John Toon (404-894-6986) (firstname.lastname@example.org)
Writer: Brett Israel
Brett Israel | newswise
NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center
Steep rise of the Bernese Alps
24.03.2017 | Universität Bern
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy