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Coral reefs in hot water as warming events slow recovery

A blacktip reef shark is among fish that inhabit coral reefs off American Samoa. Bleaching events are threatening reefs, a major source of food for more than a billion people worldwide. [Credit: Zack Gold/UCLA]

As the world's oceans heat up with climate change, coral reefs are increasingly under threat. Bleaching events—defense mechanisms against high temperatures that turn corals white—have become more frequent.


 

From 2010 to 2016, UCLA researchers studied corals off the coast of American Samoa in the South Pacific Ocean to better understand the bleaching process and what it means for the future of these iconic places.

Looking at four similar species of coral, a recently published study found that some corals are more resilient than others—but the resilience comes at a cost: They grow more slowly, making reef recovery a longer process.

Coral reefs are home to about a quarter of all marine life. Protecting them is critical not only to conserve ecosystems, but also to maintain tourism, fishing, and a major source of food for more than a billion people worldwide, said Zack Gold, a doctoral candidate in UCLA Professor Paul Barber's lab and lead author of the study.

"You have 261 million people in Indonesia alone who are dependent on seafood for the vast majority of their protein," Gold said. "Losing that would be huge. It's a security issue."

Corals are made up of two types of species working together: invertebrate anemone-like animals and single-celled algae. The invertebrates take the form of polyps and live together in colonies made up of thousands or millions of individual organisms. The algae live inside those organisms' tissues, where they are protected and given nutrients. In return, the animals get up to 90 percent of their food from the algae in the form of sugars produced by photosynthesis—the solar-powered process by which plants and other organisms create food from water and carbon dioxide.

When rise above 93 degrees or so for an extended period of time, the photosynthesis process breaks down and algae begin producing chemicals that are unhealthy to the corals, Gold said. In response, the corals reject and expel the algae. Because the algae give corals most of their color, the process turns reefs a ghostly white.

Expelling algae protects corals over the short term, but it deprives them of their primary food source, Gold said. Many never recover, and the ones that do take up to one year to return to a normal rate of growth after temperatures go back down, the study found.

Read more at: https://phys.org/news/2018-02-coral-reefs-hot-events-recovery.html#jCp

As the world's oceans heat up with climate change, coral reefs are increasingly under threat. Bleaching events—defense mechanisms against high temperatures that turn corals white—have become more frequent.


 

From 2010 to 2016, UCLA researchers studied corals off the coast of American Samoa in the South Pacific Ocean to better understand the bleaching process and what it means for the future of these iconic places.

Looking at four similar species of coral, a recently published study found that some corals are more resilient than others—but the resilience comes at a cost: They grow more slowly, making reef recovery a longer process.

Coral reefs are home to about a quarter of all marine life. Protecting them is critical not only to conserve ecosystems, but also to maintain tourism, fishing, and a major source of food for more than a billion people worldwide, said Zack Gold, a doctoral candidate in UCLA Professor Paul Barber's lab and lead author of the study.

"You have 261 million people in Indonesia alone who are dependent on seafood for the vast majority of their protein," Gold said. "Losing that would be huge. It's a security issue."

Corals are made up of two types of species working together: invertebrate anemone-like animals and single-celled algae. The invertebrates take the form of polyps and live together in colonies made up of thousands or millions of individual organisms. The algae live inside those organisms' tissues, where they are protected and given nutrients. In return, the animals get up to 90 percent of their food from the algae in the form of sugars produced by photosynthesis—the solar-powered process by which plants and other organisms create food from water and carbon dioxide.

When rise above 93 degrees or so for an extended period of time, the photosynthesis process breaks down and algae begin producing chemicals that are unhealthy to the corals, Gold said. In response, the corals reject and expel the algae. Because the algae give corals most of their color, the process turns reefs a ghostly white.

Expelling algae protects corals over the short term, but it deprives them of their primary food source, Gold said. Many never recover, and the ones that do take up to one year to return to a normal rate of growth after temperatures go back down, the study found.

Read more at: https://phys.org/news/2018-02-coral-reefs-hot-events-recovery.html#jCp

As the world's oceans heat up with climate change, coral reefs are increasingly under threat. Bleaching events—defense mechanisms against high temperatures that turn corals white—have become more frequent.


 

From 2010 to 2016, UCLA researchers studied corals off the coast of American Samoa in the South Pacific Ocean to better understand the bleaching process and what it means for the future of these iconic places.

Looking at four similar species of coral, a recently published study found that some corals are more resilient than others—but the resilience comes at a cost: They grow more slowly, making reef recovery a longer process.

Coral reefs are home to about a quarter of all marine life. Protecting them is critical not only to conserve ecosystems, but also to maintain tourism, fishing, and a major source of food for more than a billion people worldwide, said Zack Gold, a doctoral candidate in UCLA Professor Paul Barber's lab and lead author of the study.

"You have 261 million people in Indonesia alone who are dependent on seafood for the vast majority of their protein," Gold said. "Losing that would be huge. It's a security issue."

Corals are made up of two types of species working together: invertebrate anemone-like animals and single-celled algae. The invertebrates take the form of polyps and live together in colonies made up of thousands or millions of individual organisms. The algae live inside those organisms' tissues, where they are protected and given nutrients. In return, the animals get up to 90 percent of their food from the algae in the form of sugars produced by photosynthesis—the solar-powered process by which plants and other organisms create food from water and carbon dioxide.

When rise above 93 degrees or so for an extended period of time, the photosynthesis process breaks down and algae begin producing chemicals that are unhealthy to the corals, Gold said. In response, the corals reject and expel the algae. Because the algae give corals most of their color, the process turns reefs a ghostly white.

Expelling algae protects corals over the short term, but it deprives them of their primary food source, Gold said. Many never recover, and the ones that do take up to one year to return to a normal rate of growth after temperatures go back down, the study found.

Read more at: https://phys.org/news/2018-02-coral-reefs-hot-events-recovery.html#jCp

As the world's oceans heat up with climate change, coral reefs are increasingly under threat. Bleaching events—defense mechanisms against high temperatures that turn corals white—have become more frequent.

From 2010 to 2016, UCLA researchers studied corals off the coast of American Samoa in the South Pacific Ocean to better understand the bleaching process and what it means for the future of these iconic places.

Looking at four similar species of coral, a recently published study found that some corals are more resilient than others—but the resilience comes at a cost: They grow more slowly, making reef recovery a longer process.

Coral reefs are home to about a quarter of all marine life. Protecting them is critical not only to conserve ecosystems, but also to maintain tourism, fishing, and a major source of food for more than a billion people worldwide, said Zack Gold, a doctoral candidate in UCLA Professor Paul Barber's lab and lead author of the study.

"You have 261 million people in Indonesia alone who are dependent on seafood for the vast majority of their protein," Gold said. "Losing that would be huge. It's a security issue."

Corals are made up of two types of species working together: invertebrate anemone-like animals and single-celled algae. The invertebrates take the form of polyps and live together in colonies made up of thousands or millions of individual organisms. The algae live inside those organisms' tissues, where they are protected and given nutrients. In return, the animals get up to 90 percent of their food from the algae in the form of sugars produced by photosynthesis—the solar-powered process by which plants and other organisms create food from water and carbon dioxide.

When ocean temperatures rise above 93 degrees or so for an extended period of time, the photosynthesis process breaks down and algae begin producing chemicals that are unhealthy to the corals, Gold said. In response, the corals reject and expel the algae. Because the algae give corals most of their color, the process turns reefs a ghostly white.

Expelling algae protects corals over the short term, but it deprives them of their primary food source, Gold said. Many never recover, and the ones that do take up to one year to return to a normal rate of growth after temperatures go back down, the study found.

Read more at: https://phys.org/news/2018-02-coral-reefs-hot-events-recovery.html#jCp