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Changes in ocean chemistry and temperature have had a dramatic effect on the diversity of corals and sea anemones, according to a team of scientists who have traced their evolution through deep time. A new study, published Aug. 31 in the journal┬áNature Ecology and Evolution, finds that reef-building corals emerged only when ocean conditions supported the construction of these creatures' stony skeletons, whereas diverse softer corals and sea anemones flourished at other times. Without a significant change to anthropogenic carbon emissions, the new findings present stark implications for the present and future of hard-bodied corals while suggesting a silver lining for the diversity of some of their softer-bodied relatives. New genetic analyses show that corals, which together with sea anemones make up a class of animals known as anthozoans, have been on the planet for 770 million years. That is 250 million years before the earliest undisputed fossil evidence of their existenceÔÇöand long enough to experience massive shifts in climate, fluctuations in┬áocean chemistry┬áand several mass extinctions. In the new study, a research team led by scientists from Harvey Mudd College, the American Museum of Natural History and the Smithsonian's National Museum of Natural History examined how these past conditions affected anthozoan diversity. That was possible thanks to a new molecular approach developed by Andrea Quattrini, research zoologist and curator of corals at the National Museum of Natural History, Catherine McFadden, a biologist at Harvey Mudd College, and Estefan├şa Rodr├şguez, a curator at the American Museum of Natural History, which allowed the team to compare nearly 2,000 key regions of anthozoan genomes to discern the evolutionary relationships between species. The team analyzed hundreds of anthozoan specimens that were collected from around the world and are now stored in museum collections. When this molecular data was aligned with fossil evidence of anthozoan history, it revealed how these diverse animals evolved over geologic time. Over the Earth's history, changes in acidity and ion concentrations have shifted the ocean's chemical composition between two states, known as aragonite and calcite seas. These changes, as well as changes in ocean water temperature, appear to have played an important role in determining what kinds of skeletons corals were able to produce and, thus, how anthozoans evolved. ´┐╝ Credit: James Reimer Stony coralsÔÇöthe type that build massive reefs that support complex marine ecosystemsÔÇötake up minerals from the water to construct hard skeletons from a form of calcium carbonate known as aragonite. Other corals, such as sea fans and black corals, build their softer skeletons from protein or calcite (a less soluble form of calcium carbonate), whereas sea anemones have no┬áskeleton┬áat all. Working with an international team of researchers, including┬áGabriela Farfan, the National Museum of Natural History's Coralyn W. Whitney Curator of Gems and Minerals, Quattrini and colleagues found that stony corals did not arise until conditions favored the construction of their aragonite skeletonsÔÇöperiods of aragonite seas, when ocean temperatures were relatively cool. During periods of calcite seas, when carbon dioxide is more abundant in the atmosphere and oceans are more acidic, evolution favored anemones and corals that built their skeletons from protein or calcite. Notably, it was these other anthozoans that fared best after reef crisesÔÇötimes when up to 90% of reef-building organisms died off as oceans warmed and became more acidic. "Our study showed that after these reef crises, we actually get an increased diversification of anthozoans in general, particularly those that can do well under these climate conditionsÔÇöones that aren't producing aragonite and aren't making big reefs," Quattrini said. That is consistent with observations from today's reefs, which are threatened by climate change and other human activities. "Current ecological studies have shown that when stony corals die off, these other anthozoans start to colonize dead coral and prosper," Quattrini said. "We actually see that in our evolutionary tree, too." ´┐╝ Sea fans--┬Čsofter-bodied coral relatives--colonizing a dead stony coral framework. Credit: David Paz-Garcia "Unfortunately, although these softer-bodied species may adapt better to climate change than stony corals, they don't form large reefs," McFadden said. "So, in the future, reefs may be replaced by different marine communities. This already appears to be happening in the Caribbean where┬ástony corals┬áare being replaced by 'forests' of sea fans." Today, about 1,300 species of stony┬ácoral┬áinhabit the ocean, favored by aragonite sea conditions. But rising levels of carbon dioxide in the atmosphere are warming and acidifying the waters, making them less hospitable for these and other organisms whose shells and skeletons are made from aragonite. "Aragonite is expected to dissolve under ocean acidification," Quattrini said. "As our seas are becoming more acidic and warmer, it's likely that the skeletons of corals will dissolve or not be able to grow." The new study suggests that as the climate changes, these ecosystems may also see increased diversification of anthozoans without aragonite skeletons. Nevertheless, loss of reef-building corals will have devastating consequences for communities who depend on reefs and the rich, complex ecosystems they support for fishing, shoreline protection and tourism. "Corals have suffered extinctions in the past when climate has posed challenges, and we'll likely see that in the future," Quattrini said. "The best way to protect them is to curb our carbon emissions." "This study shows us how nature through evolution is able to adapt, survive and reinvent itself, so when hard corals are not able to survive, their soft-bodied relatives such as┬ásea anemones┬áwill thrive instead," Rodr├şguez said. "The question is whether we will be able to adapt and reinvent ourselves once nature, as we currently know it, is not there anymore." More information:┬áPalaeoclimate ocean conditions shaped the evolution of corals and their skeletons through deep time,┬áNature Ecology and Evolution┬á(2020).┬áDOI: 10.1038/s41559-020-01291-1┬á,┬á[www.nature.com/articles/s41559-020-01291-1](http://www.nature.com/articles/s41559-020-01291-1) Journal information:┬áNature Ecology & Evolution┬á Provided by┬áSmithsonian┬á Feedback to editors Related Recommended ´┐╝ Ocean acidification causing coral 'osteoporosis' on iconic reefs Aug 27, 2020 ´┐╝ Coral skeleton crystals record ocean acidification Jul 11, 2019 ´┐╝ Stony corals more resistant to climate change than thought, study finds Jun 01, 2017 ´┐╝ New research suggests Caribbean gorgonian corals are resistant to ocean acidification Dec 08, 2014 ´┐╝ Soft corals near Virgin Islands recover from hurricanes, but stony corals declining Mar 16, 2020 ´┐╝ Research aims to preserve the future of Ningaloo Reef corals Jul 30, 2019 Load comments┬á(1) ´┐╝ Radiocarbon dating and CT scans reveal Bronze Age tradition of keeping human remains 9 hours ago ´┐╝ How to weigh a dinosaur 10 hours ago ´┐╝ Researchers develop new X-ray detection technology 12 hours ago ´┐╝ Scientists develop first drug-like compounds to inhibit elusive cancer-linked enzymes 12 hours ago ´┐╝ Scientists reveal secret of material for promising infrared cameras 13 hours ago ´┐╝ To the choir: Forward-thinking faculty sharing innovations mostly among themselves 13 hours ago ´┐╝ Researchers develop molecule to store solar energy 15 hours ago ´┐╝ Researchers develop dustbuster for the moon 15 hours ago ´┐╝ Demonstrating the dynamics of electron-light interaction originating from first principle 15 hours ago ´┐╝ Following African elephant trails to approach conservation differently 15 hours ago ´┐╝ New evidence for quantum fluctuations near a quantum critical point in a superconductor
Changes in ocean chemistry and temperature have had a dramatic effect on the diversity of corals and sea anemones, according to a team of scientists who have traced their evolution through deep time. A new study, published Aug. 31 in the journal┬áNature Ecology and Evolution, finds that reef-building corals emerged only when ocean conditions supported the construction of these creatures' stony skeletons, whereas diverse softer corals and sea anemones flourished at other times. Without a significant change to anthropogenic carbon emissions, the new findings present stark implications for the present and future of hard-bodied corals while suggesting a silver lining for the diversity of some of their softer-bodied relatives. New genetic analyses show that corals, which together with sea anemones make up a class of animals known as anthozoans, have been on the planet for 770 million years. That is 250 million years before the earliest undisputed fossil evidence of their existenceÔÇöand long enough to experience massive shifts in climate, fluctuations in┬áocean chemistry┬áand several mass extinctions. In the new study, a research team led by scientists from Harvey Mudd College, the American Museum of Natural History and the Smithsonian's National Museum of Natural History examined how these past conditions affected anthozoan diversity. That was possible thanks to a new molecular approach developed by Andrea Quattrini, research zoologist and curator of corals at the National Museum of Natural History, Catherine McFadden, a biologist at Harvey Mudd College, and Estefan├şa Rodr├şguez, a curator at the American Museum of Natural History, which allowed the team to compare nearly 2,000 key regions of anthozoan genomes to discern the evolutionary relationships between species. The team analyzed hundreds of anthozoan specimens that were collected from around the world and are now stored in museum collections. When this molecular data was aligned with fossil evidence of anthozoan history, it revealed how these diverse animals evolved over geologic time. Over the Earth's history, changes in acidity and ion concentrations have shifted the ocean's chemical composition between two states, known as aragonite and calcite seas. These changes, as well as changes in ocean water temperature, appear to have played an important role in determining what kinds of skeletons corals were able to produce and, thus, how anthozoans evolved. ´┐╝ Credit: James Reimer Stony coralsÔÇöthe type that build massive reefs that support complex marine ecosystemsÔÇötake up minerals from the water to construct hard skeletons from a form of calcium carbonate known as aragonite. Other corals, such as sea fans and black corals, build their softer skeletons from protein or calcite (a less soluble form of calcium carbonate), whereas sea anemones have no┬áskeleton┬áat all. Working with an international team of researchers, including┬áGabriela Farfan, the National Museum of Natural History's Coralyn W. Whitney Curator of Gems and Minerals, Quattrini and colleagues found that stony corals did not arise until conditions favored the construction of their aragonite skeletonsÔÇöperiods of aragonite seas, when ocean temperatures were relatively cool. During periods of calcite seas, when carbon dioxide is more abundant in the atmosphere and oceans are more acidic, evolution favored anemones and corals that built their skeletons from protein or calcite. Notably, it was these other anthozoans that fared best after reef crisesÔÇötimes when up to 90% of reef-building organisms died off as oceans warmed and became more acidic. "Our study showed that after these reef crises, we actually get an increased diversification of anthozoans in general, particularly those that can do well under these climate conditionsÔÇöones that aren't producing aragonite and aren't making big reefs," Quattrini said. That is consistent with observations from today's reefs, which are threatened by climate change and other human activities. "Current ecological studies have shown that when stony corals die off, these other anthozoans start to colonize dead coral and prosper," Quattrini said. "We actually see that in our evolutionary tree, too." ´┐╝ Sea fans--┬Čsofter-bodied coral relatives--colonizing a dead stony coral framework. Credit: David Paz-Garcia "Unfortunately, although these softer-bodied species may adapt better to climate change than stony corals, they don't form large reefs," McFadden said. "So, in the future, reefs may be replaced by different marine communities. This already appears to be happening in the Caribbean where┬ástony corals┬áare being replaced by 'forests' of sea fans." Today, about 1,300 species of stony┬ácoral┬áinhabit the ocean, favored by aragonite sea conditions. But rising levels of carbon dioxide in the atmosphere are warming and acidifying the waters, making them less hospitable for these and other organisms whose shells and skeletons are made from aragonite. "Aragonite is expected to dissolve under ocean acidification," Quattrini said. "As our seas are becoming more acidic and warmer, it's likely that the skeletons of corals will dissolve or not be able to grow." The new study suggests that as the climate changes, these ecosystems may also see increased diversification of anthozoans without aragonite skeletons. Nevertheless, loss of reef-building corals will have devastating consequences for communities who depend on reefs and the rich, complex ecosystems they support for fishing, shoreline protection and tourism. "Corals have suffered extinctions in the past when climate has posed challenges, and we'll likely see that in the future," Quattrini said. "The best way to protect them is to curb our carbon emissions." "This study shows us how nature through evolution is able to adapt, survive and reinvent itself, so when hard corals are not able to survive, their soft-bodied relatives such as┬ásea anemones┬áwill thrive instead," Rodr├şguez said. "The question is whether we will be able to adapt and reinvent ourselves once nature, as we currently know it, is not there anymore." More information:┬áPalaeoclimate ocean conditions shaped the evolution of corals and their skeletons through deep time,┬áNature Ecology and Evolution┬á(2020).┬áDOI: 10.1038/s41559-020-01291-1┬á,┬á[www.nature.com/articles/s41559-020-01291-1](http://www.nature.com/articles/s41559-020-01291-1) Journal information:┬áNature Ecology & Evolution┬á Provided by┬áSmithsonian┬á Feedback to editors Related Recommended ´┐╝ Ocean acidification causing coral 'osteoporosis' on iconic reefs Aug 27, 2020 ´┐╝ Coral skeleton crystals record ocean acidification Jul 11, 2019 ´┐╝ Stony corals more resistant to climate change than thought, study finds Jun 01, 2017 ´┐╝ New research suggests Caribbean gorgonian corals are resistant to ocean acidification Dec 08, 2014 ´┐╝ Soft corals near Virgin Islands recover from hurricanes, but stony corals declining Mar 16, 2020 ´┐╝ Research aims to preserve the future of Ningaloo Reef corals Jul 30, 2019 Load comments┬á(1) ´┐╝ Radiocarbon dating and CT scans reveal Bronze Age tradition of keeping human remains 9 hours ago ´┐╝ How to weigh a dinosaur 10 hours ago ´┐╝ Researchers develop new X-ray detection technology 12 hours ago ´┐╝ Scientists develop first drug-like compounds to inhibit elusive cancer-linked enzymes 12 hours ago ´┐╝ Scientists reveal secret of material for promising infrared cameras 13 hours ago ´┐╝ To the choir: Forward-thinking faculty sharing innovations mostly among themselves 13 hours ago ´┐╝ Researchers develop molecule to store solar energy 15 hours ago ´┐╝ Researchers develop dustbuster for the moon 15 hours ago ´┐╝ Demonstrating the dynamics of electron-light interaction originating from first principle 15 hours ago ´┐╝ Following African elephant trails to approach conservation differently 15 hours ago ´┐╝ New evidence for quantum fluctuations near a quantum critical point in a superconductor
Changes in ocean chemistry and temperature have had a dramatic effect on the diversity of corals and sea anemones, according to a team of scientists who have traced their evolution through deep time. A new study, published Aug. 31 in the journal┬áNature Ecology and Evolution, finds that reef-building corals emerged only when ocean conditions supported the construction of these creatures' stony skeletons, whereas diverse softer corals and sea anemones flourished at other times. Without a significant change to anthropogenic carbon emissions, the new findings present stark implications for the present and future of hard-bodied corals while suggesting a silver lining for the diversity of some of their softer-bodied relatives. New genetic analyses show that corals, which together with sea anemones make up a class of animals known as anthozoans, have been on the planet for 770 million years. That is 250 million years before the earliest undisputed fossil evidence of their existenceÔÇöand long enough to experience massive shifts in climate, fluctuations in┬áocean chemistry┬áand several mass extinctions. In the new study, a research team led by scientists from Harvey Mudd College, the American Museum of Natural History and the Smithsonian's National Museum of Natural History examined how these past conditions affected anthozoan diversity. That was possible thanks to a new molecular approach developed by Andrea Quattrini, research zoologist and curator of corals at the National Museum of Natural History, Catherine McFadden, a biologist at Harvey Mudd College, and Estefan├şa Rodr├şguez, a curator at the American Museum of Natural History, which allowed the team to compare nearly 2,000 key regions of anthozoan genomes to discern the evolutionary relationships between species. The team analyzed hundreds of anthozoan specimens that were collected from around the world and are now stored in museum collections. When this molecular data was aligned with fossil evidence of anthozoan history, it revealed how these diverse animals evolved over geologic time. Over the Earth's history, changes in acidity and ion concentrations have shifted the ocean's chemical composition between two states, known as aragonite and calcite seas. These changes, as well as changes in ocean water temperature, appear to have played an important role in determining what kinds of skeletons corals were able to produce and, thus, how anthozoans evolved. ´┐╝ Credit: James Reimer Stony coralsÔÇöthe type that build massive reefs that support complex marine ecosystemsÔÇötake up minerals from the water to construct hard skeletons from a form of calcium carbonate known as aragonite. Other corals, such as sea fans and black corals, build their softer skeletons from protein or calcite (a less soluble form of calcium carbonate), whereas sea anemones have no┬áskeleton┬áat all. Working with an international team of researchers, including┬áGabriela Farfan, the National Museum of Natural History's Coralyn W. Whitney Curator of Gems and Minerals, Quattrini and colleagues found that stony corals did not arise until conditions favored the construction of their aragonite skeletonsÔÇöperiods of aragonite seas, when ocean temperatures were relatively cool. During periods of calcite seas, when carbon dioxide is more abundant in the atmosphere and oceans are more acidic, evolution favored anemones and corals that built their skeletons from protein or calcite. Notably, it was these other anthozoans that fared best after reef crisesÔÇötimes when up to 90% of reef-building organisms died off as oceans warmed and became more acidic. "Our study showed that after these reef crises, we actually get an increased diversification of anthozoans in general, particularly those that can do well under these climate conditionsÔÇöones that aren't producing aragonite and aren't making big reefs," Quattrini said. That is consistent with observations from today's reefs, which are threatened by climate change and other human activities. "Current ecological studies have shown that when stony corals die off, these other anthozoans start to colonize dead coral and prosper," Quattrini said. "We actually see that in our evolutionary tree, too." ´┐╝ Sea fans--┬Čsofter-bodied coral relatives--colonizing a dead stony coral framework. Credit: David Paz-Garcia "Unfortunately, although these softer-bodied species may adapt better to climate change than stony corals, they don't form large reefs," McFadden said. "So, in the future, reefs may be replaced by different marine communities. This already appears to be happening in the Caribbean where┬ástony corals┬áare being replaced by 'forests' of sea fans." Today, about 1,300 species of stony┬ácoral┬áinhabit the ocean, favored by aragonite sea conditions. But rising levels of carbon dioxide in the atmosphere are warming and acidifying the waters, making them less hospitable for these and other organisms whose shells and skeletons are made from aragonite. "Aragonite is expected to dissolve under ocean acidification," Quattrini said. "As our seas are becoming more acidic and warmer, it's likely that the skeletons of corals will dissolve or not be able to grow." The new study suggests that as the climate changes, these ecosystems may also see increased diversification of anthozoans without aragonite skeletons. Nevertheless, loss of reef-building corals will have devastating consequences for communities who depend on reefs and the rich, complex ecosystems they support for fishing, shoreline protection and tourism. "Corals have suffered extinctions in the past when climate has posed challenges, and we'll likely see that in the future," Quattrini said. "The best way to protect them is to curb our carbon emissions." "This study shows us how nature through evolution is able to adapt, survive and reinvent itself, so when hard corals are not able to survive, their soft-bodied relatives such as┬ásea anemones┬áwill thrive instead," Rodr├şguez said. "The question is whether we will be able to adapt and reinvent ourselves once nature, as we currently know it, is not there anymore." More information:┬áPalaeoclimate ocean conditions shaped the evolution of corals and their skeletons through deep time,┬áNature Ecology and Evolution┬á(2020).┬áDOI: 10.1038/s41559-020-01291-1┬á,┬á[www.nature.com/articles/s41559-020-01291-1](http://www.nature.com/articles/s41559-020-01291-1) Journal information:┬áNature Ecology & Evolution┬á Provided by┬áSmithsonian┬á Feedback to editors Related Recommended ´┐╝ Ocean acidification causing coral 'osteoporosis' on iconic reefs Aug 27, 2020 ´┐╝ Coral skeleton crystals record ocean acidification Jul 11, 2019 ´┐╝ Stony corals more resistant to climate change than thought, study finds Jun 01, 2017 ´┐╝ New research suggests Caribbean gorgonian corals are resistant to ocean acidification Dec 08, 2014 ´┐╝ Soft corals near Virgin Islands recover from hurricanes, but stony corals declining Mar 16, 2020 ´┐╝ Research aims to preserve the future of Ningaloo Reef corals Jul 30, 2019 Load comments┬á(1) ´┐╝ Radiocarbon dating and CT scans reveal Bronze Age tradition of keeping human remains 9 hours ago ´┐╝ How to weigh a dinosaur 10 hours ago ´┐╝ Researchers develop new X-ray detection technology 12 hours ago ´┐╝ Scientists develop first drug-like compounds to inhibit elusive cancer-linked enzymes 12 hours ago ´┐╝ Scientists reveal secret of material for promising infrared cameras 13 hours ago ´┐╝ To the choir: Forward-thinking faculty sharing innovations mostly among themselves 13 hours ago ´┐╝ Researchers develop molecule to store solar energy 15 hours ago ´┐╝ Researchers develop dustbuster for the moon 15 hours ago ´┐╝ Demonstrating the dynamics of electron-light interaction originating from first principle 15 hours ago ´┐╝ Following African elephant trails to approach conservation differently 15 hours ago ´┐╝ New evidence for quantum fluctuations near a quantum critical point in a superconductor
Changes in ocean chemistry and temperature have had a dramatic effect on the diversity of corals and sea anemones, according to a team of scientists who have traced their evolution through deep time. A new study, published Aug. 31 in the journal┬áNature Ecology and Evolution, finds that reef-building corals emerged only when ocean conditions supported the construction of these creatures' stony skeletons, whereas diverse softer corals and sea anemones flourished at other times. Without a significant change to anthropogenic carbon emissions, the new findings present stark implications for the present and future of hard-bodied corals while suggesting a silver lining for the diversity of some of their softer-bodied relatives. New genetic analyses show that corals, which together with sea anemones make up a class of animals known as anthozoans, have been on the planet for 770 million years. That is 250 million years before the earliest undisputed fossil evidence of their existenceÔÇöand long enough to experience massive shifts in climate, fluctuations in┬áocean chemistry┬áand several mass extinctions. In the new study, a research team led by scientists from Harvey Mudd College, the American Museum of Natural History and the Smithsonian's National Museum of Natural History examined how these past conditions affected anthozoan diversity. That was possible thanks to a new molecular approach developed by Andrea Quattrini, research zoologist and curator of corals at the National Museum of Natural History, Catherine McFadden, a biologist at Harvey Mudd College, and Estefan├şa Rodr├şguez, a curator at the American Museum of Natural History, which allowed the team to compare nearly 2,000 key regions of anthozoan genomes to discern the evolutionary relationships between species. The team analyzed hundreds of anthozoan specimens that were collected from around the world and are now stored in museum collections. When this molecular data was aligned with fossil evidence of anthozoan history, it revealed how these diverse animals evolved over geologic time. Over the Earth's history, changes in acidity and ion concentrations have shifted the ocean's chemical composition between two states, known as aragonite and calcite seas. These changes, as well as changes in ocean water temperature, appear to have played an important role in determining what kinds of skeletons corals were able to produce and, thus, how anthozoans evolved. ´┐╝ Credit: James Reimer Stony coralsÔÇöthe type that build massive reefs that support complex marine ecosystemsÔÇötake up minerals from the water to construct hard skeletons from a form of calcium carbonate known as aragonite. Other corals, such as sea fans and black corals, build their softer skeletons from protein or calcite (a less soluble form of calcium carbonate), whereas sea anemones have no┬áskeleton┬áat all. Working with an international team of researchers, including┬áGabriela Farfan, the National Museum of Natural History's Coralyn W. Whitney Curator of Gems and Minerals, Quattrini and colleagues found that stony corals did not arise until conditions favored the construction of their aragonite skeletonsÔÇöperiods of aragonite seas, when ocean temperatures were relatively cool. During periods of calcite seas, when carbon dioxide is more abundant in the atmosphere and oceans are more acidic, evolution favored anemones and corals that built their skeletons from protein or calcite. Notably, it was these other anthozoans that fared best after reef crisesÔÇötimes when up to 90% of reef-building organisms died off as oceans warmed and became more acidic. "Our study showed that after these reef crises, we actually get an increased diversification of anthozoans in general, particularly those that can do well under these climate conditionsÔÇöones that aren't producing aragonite and aren't making big reefs," Quattrini said. That is consistent with observations from today's reefs, which are threatened by climate change and other human activities. "Current ecological studies have shown that when stony corals die off, these other anthozoans start to colonize dead coral and prosper," Quattrini said. "We actually see that in our evolutionary tree, too." ´┐╝ Sea fans--┬Čsofter-bodied coral relatives--colonizing a dead stony coral framework. Credit: David Paz-Garcia "Unfortunately, although these softer-bodied species may adapt better to climate change than stony corals, they don't form large reefs," McFadden said. "So, in the future, reefs may be replaced by different marine communities. This already appears to be happening in the Caribbean where┬ástony corals┬áare being replaced by 'forests' of sea fans." Today, about 1,300 species of stony┬ácoral┬áinhabit the ocean, favored by aragonite sea conditions. But rising levels of carbon dioxide in the atmosphere are warming and acidifying the waters, making them less hospitable for these and other organisms whose shells and skeletons are made from aragonite. "Aragonite is expected to dissolve under ocean acidification," Quattrini said. "As our seas are becoming more acidic and warmer, it's likely that the skeletons of corals will dissolve or not be able to grow." The new study suggests that as the climate changes, these ecosystems may also see increased diversification of anthozoans without aragonite skeletons. Nevertheless, loss of reef-building corals will have devastating consequences for communities who depend on reefs and the rich, complex ecosystems they support for fishing, shoreline protection and tourism. "Corals have suffered extinctions in the past when climate has posed challenges, and we'll likely see that in the future," Quattrini said. "The best way to protect them is to curb our carbon emissions." "This study shows us how nature through evolution is able to adapt, survive and reinvent itself, so when hard corals are not able to survive, their soft-bodied relatives such as┬ásea anemones┬áwill thrive instead," Rodr├şguez said. "The question is whether we will be able to adapt and reinvent ourselves once nature, as we currently know it, is not there anymore." More information:┬áPalaeoclimate ocean conditions shaped the evolution of corals and their skeletons through deep time,┬áNature Ecology and Evolution┬á(2020).┬áDOI: 10.1038/s41559-020-01291-1┬á,┬á[www.nature.com/articles/s41559-020-01291-1](http://www.nature.com/articles/s41559-020-01291-1) Journal information:┬áNature Ecology & Evolution┬á Provided by┬áSmithsonian┬á Feedback to editors Related Recommended ´┐╝ Ocean acidification causing coral 'osteoporosis' on iconic reefs Aug 27, 2020 ´┐╝ Coral skeleton crystals record ocean acidification Jul 11, 2019 ´┐╝ Stony corals more resistant to climate change than thought, study finds Jun 01, 2017 ´┐╝ New research suggests Caribbean gorgonian corals are resistant to ocean acidification Dec 08, 2014 ´┐╝ Soft corals near Virgin Islands recover from hurricanes, but stony corals declining Mar 16, 2020 ´┐╝ Research aims to preserve the future of Ningaloo Reef corals Jul 30, 2019 Load comments┬á(1) ´┐╝ Radiocarbon dating and CT scans reveal Bronze Age tradition of keeping human remains 9 hours ago ´┐╝ How to weigh a dinosaur 10 hours ago ´┐╝ Researchers develop new X-ray detection technology 12 hours ago ´┐╝ Scientists develop first drug-like compounds to inhibit elusive cancer-linked enzymes 12 hours ago ´┐╝ Scientists reveal secret of material for promising infrared cameras 13 hours ago ´┐╝ To the choir: Forward-thinking faculty sharing innovations mostly among themselves 13 hours ago ´┐╝ Researchers develop molecule to store solar energy 15 hours ago ´┐╝ Researchers develop dustbuster for the moon 15 hours ago ´┐╝ Demonstrating the dynamics of electron-light interaction originating from first principle 15 hours ago ´┐╝ Following African elephant trails to approach conservation differently 15 hours ago ´┐╝ New evidence for quantum fluctuations near a quantum critical point in a superconductor
Changes in ocean chemistry and temperature have had a dramatic effect on the diversity of corals and sea anemones, according to a team of scientists who have traced their evolution through deep time. A new study, published Aug. 31 in the journal┬áNature Ecology and Evolution, finds that reef-building corals emerged only when ocean conditions supported the construction of these creatures' stony skeletons, whereas diverse softer corals and sea anemones flourished at other times. Without a significant change to anthropogenic carbon emissions, the new findings present stark implications for the present and future of hard-bodied corals while suggesting a silver lining for the diversity of some of their softer-bodied relatives. New genetic analyses show that corals, which together with sea anemones make up a class of animals known as anthozoans, have been on the planet for 770 million years. That is 250 million years before the earliest undisputed fossil evidence of their existenceÔÇöand long enough to experience massive shifts in climate, fluctuations in┬áocean chemistry┬áand several mass extinctions. In the new study, a research team led by scientists from Harvey Mudd College, the American Museum of Natural History and the Smithsonian's National Museum of Natural History examined how these past conditions affected anthozoan diversity. That was possible thanks to a new molecular approach developed by Andrea Quattrini, research zoologist and curator of corals at the National Museum of Natural History, Catherine McFadden, a biologist at Harvey Mudd College, and Estefan├şa Rodr├şguez, a curator at the American Museum of Natural History, which allowed the team to compare nearly 2,000 key regions of anthozoan genomes to discern the evolutionary relationships between species. The team analyzed hundreds of anthozoan specimens that were collected from around the world and are now stored in museum collections. When this molecular data was aligned with fossil evidence of anthozoan history, it revealed how these diverse animals evolved over geologic time. Over the Earth's history, changes in acidity and ion concentrations have shifted the ocean's chemical composition between two states, known as aragonite and calcite seas. These changes, as well as changes in ocean water temperature, appear to have played an important role in determining what kinds of skeletons corals were able to produce and, thus, how anthozoans evolved. ´┐╝ Credit: James Reimer Stony coralsÔÇöthe type that build massive reefs that support complex marine ecosystemsÔÇötake up minerals from the water to construct hard skeletons from a form of calcium carbonate known as aragonite. Other corals, such as sea fans and black corals, build their softer skeletons from protein or calcite (a less soluble form of calcium carbonate), whereas sea anemones have no┬áskeleton┬áat all. Working with an international team of researchers, including┬áGabriela Farfan, the National Museum of Natural History's Coralyn W. Whitney Curator of Gems and Minerals, Quattrini and colleagues found that stony corals did not arise until conditions favored the construction of their aragonite skeletonsÔÇöperiods of aragonite seas, when ocean temperatures were relatively cool. During periods of calcite seas, when carbon dioxide is more abundant in the atmosphere and oceans are more acidic, evolution favored anemones and corals that built their skeletons from protein or calcite. Notably, it was these other anthozoans that fared best after reef crisesÔÇötimes when up to 90% of reef-building organisms died off as oceans warmed and became more acidic. "Our study showed that after these reef crises, we actually get an increased diversification of anthozoans in general, particularly those that can do well under these climate conditionsÔÇöones that aren't producing aragonite and aren't making big reefs," Quattrini said. That is consistent with observations from today's reefs, which are threatened by climate change and other human activities. "Current ecological studies have shown that when stony corals die off, these other anthozoans start to colonize dead coral and prosper," Quattrini said. "We actually see that in our evolutionary tree, too." ´┐╝ Sea fans--┬Čsofter-bodied coral relatives--colonizing a dead stony coral framework. Credit: David Paz-Garcia "Unfortunately, although these softer-bodied species may adapt better to climate change than stony corals, they don't form large reefs," McFadden said. "So, in the future, reefs may be replaced by different marine communities. This already appears to be happening in the Caribbean where┬ástony corals┬áare being replaced by 'forests' of sea fans." Today, about 1,300 species of stony┬ácoral┬áinhabit the ocean, favored by aragonite sea conditions. But rising levels of carbon dioxide in the atmosphere are warming and acidifying the waters, making them less hospitable for these and other organisms whose shells and skeletons are made from aragonite. "Aragonite is expected to dissolve under ocean acidification," Quattrini said. "As our seas are becoming more acidic and warmer, it's likely that the skeletons of corals will dissolve or not be able to grow." The new study suggests that as the climate changes, these ecosystems may also see increased diversification of anthozoans without aragonite skeletons. Nevertheless, loss of reef-building corals will have devastating consequences for communities who depend on reefs and the rich, complex ecosystems they support for fishing, shoreline protection and tourism. "Corals have suffered extinctions in the past when climate has posed challenges, and we'll likely see that in the future," Quattrini said. "The best way to protect them is to curb our carbon emissions." "This study shows us how nature through evolution is able to adapt, survive and reinvent itself, so when hard corals are not able to survive, their soft-bodied relatives such as┬ásea anemones┬áwill thrive instead," Rodr├şguez said. "The question is whether we will be able to adapt and reinvent ourselves once nature, as we currently know it, is not there anymore." More information:┬áPalaeoclimate ocean conditions shaped the evolution of corals and their skeletons through deep time,┬áNature Ecology and Evolution┬á(2020).┬áDOI: 10.1038/s41559-020-01291-1┬á,┬á[www.nature.com/articles/s41559-020-01291-1](http://www.nature.com/articles/s41559-020-01291-1) Journal information:┬áNature Ecology & Evolution┬á Provided by┬áSmithsonian┬á Feedback to editors Related Recommended ´┐╝ Ocean acidification causing coral 'osteoporosis' on iconic reefs Aug 27, 2020 ´┐╝ Coral skeleton crystals record ocean acidification Jul 11, 2019 ´┐╝ Stony corals more resistant to climate change than thought, study finds Jun 01, 2017 ´┐╝ New research suggests Caribbean gorgonian corals are resistant to ocean acidification Dec 08, 2014 ´┐╝ Soft corals near Virgin Islands recover from hurricanes, but stony corals declining Mar 16, 2020 ´┐╝ Research aims to preserve the future of Ningaloo Reef corals Jul 30, 2019 Load comments┬á(1) ´┐╝ Radiocarbon dating and CT scans reveal Bronze Age tradition of keeping human remains 9 hours ago ´┐╝ How to weigh a dinosaur 10 hours ago ´┐╝ Researchers develop new X-ray detection technology 12 hours ago ´┐╝ Scientists develop first drug-like compounds to inhibit elusive cancer-linked enzymes 12 hours ago ´┐╝ Scientists reveal secret of material for promising infrared cameras 13 hours ago ´┐╝ To the choir: Forward-thinking faculty sharing innovations mostly among themselves 13 hours ago ´┐╝ Researchers develop molecule to store solar energy 15 hours ago ´┐╝ Researchers develop dustbuster for the moon 15 hours ago ´┐╝ Demonstrating the dynamics of electron-light interaction originating from first principle 15 hours ago ´┐╝ Following African elephant trails to approach conservation differently 15 hours ago ´┐╝ New evidence for quantum fluctuations near a quantum critical point in a superconductor
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