coral reef tagged posts

Coral reefs threatened by freshwater as much as rising temps

Coral reef threatened by freshwater

Scientists have found that dramatic changes in ocean salinity trigger the same stress response in corals as extreme heat. For example, when severe freshwater flooding greatly reduces the salinity of the seawater, corals can experience potentially fatal “freshwater bleaching.”

The researchers used the sequenced genome of the common reef-building coral Acropora millepora to detect changes in the coral’s biology when exposed to a sudden drop in seawater salinity. The experts observed a biochemical response which was similar to that from marine heatwaves, but potentially more damaging.

“Using the sophisticated labs at the National Sea Simulator, we put both young and adult corals under a salinity stress test to see how they respond to differing salinity concentrations,” said stu...

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Are Hawaiian Corals Adjusting to Warmer Temperatures?

Co-author Keisha Bahr surveying a healthy coral colony. PC: Ji Hoon.

A team of researchers from the University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology and the Bernice Pauahi Bishop Museum conducted a study of coral resiliency that showed some corals are better able to tolerate heat than similar corals tested in the 1970s. But scientists say it will not be fast enough to fight off rising sea temperatures.

The scientists replicated the identical experimental system, methodology, coral species, collection site, and even brought in one of the original researchers, Steve Coles, adjunct faculty at the UH Mānoa Hawai‘i Institute of Marine Biology (HIMB)...

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What the world can learn from Brazilian coral reefs

Field work in murky water to illustrate how Brazilian reefs surrounded by murky water due to a greater river input to coastal waters

We usually imagine coral reefs as underwater tropical wonderlands, bursting with life and living on a fragile balance. 

While climate change and other human impacts are indeed threatening coral reefs on a global scale, not all corals are the same. 

In fact, here in Brazil our reefs have very low diversity of coral species, but some of these species are only found here and they are pretty special. 

Is Brazilian coral more resistant to climate change?

While many reefs have suffered from especially warm ocean temperatures in recent years, coral species in Brazil have been particularly sturdy. In fact, we haven’t seen any mass mortality events related to bleaching so far.

So, could Brazilian corals hold the key to more resilient reefs?

The natural conditions found in coral...

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Scientists Find Some Hope for Coral Reefs

Healthy Coral Reef

Among the threatened corals of Australia’s Great Barrier Reef, one of the natural wonders of the world that has been ravaged by global warming, researchers have found a reason for optimism — or at least a reason not to despair completely.

Coral reefs, which by some estimates support a quarter of all ocean life, are harmed by warming oceans. The effects can be seen in the loss of their vibrant colors, a phenomenon known as bleaching. But after ocean temperatures surged in 2016 around the Great Barrier Reef, causing severe damage, researchers found that the corals that survived were more resistant to another period of extreme warmth the following year.

“It’s one enormous natural selection event,” said Terry Hughes, an expert on coral reefs at James Cook University in Australia and...

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We can assess the health of coral reefs by the sounds algae make

beautiful colours of the coral reef

When oceanographers Lauren and Simon Freeman, a couple who work with the U.S. Naval Undersea Warfare Center in Rhode Island, first mentioned what they’d heard to others, the response was not exactly positive. They’d been listening to sounds they were certain had been made by marine macroalgae covering underwater coral reefs in Hawaii. Simon recalls, “We were told the sound was from snapping shrimp, end of story.” But, listening at a few locations, they saw a correlation between the amount of sound and the quantity of algae. Further research has pretty much confirmed their hunch, and they’ve introduced a new avenue for marine acoustic ecology: Assessing the health of reefs according to the sounds they make.

Algae, like plants on dry land, convert sunlight and carbon dioxide to energy vi...

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Coral Reefs Around The World Are In Grave Danger

Coral reefs are under threat

What’s Happening

One of the most wonderous living things on earth is coral. Humans view its diversity and hues as a gorgeous, underwater decoration. But, it is a living organism that supports the lives of hundreds, if not thousands, of species in the underwater ecosystem. Man may appreciate its wonder, but our destructive tendencies are harming this vital member of the oceans and seas. Here’s what you need to know about the grave threats facing coral reefs. If we don’t act soon, we may destroy these beautiful pieces of the earth.

What Exactly Is Coral?

Corals are relatives of the sea anemone. They are all made of the same simple structure: the polyp. The polyp resembles a tin can open at one end: the open end has a mouth surrounded by tentacles...

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Teaching coral to toughen up could help reefs survive climate change

Diver photographing a coral reef

As the world’s oceans continue to warm, coral reefs are struggling to survive. In recent years large swaths of some of the world’s biggest and best known reefs have died, and a recent UN report maintains that the reefs could “cease to exist as functioning coral reef ecosystems by the end of this century” unless steps are taking to protect them.

But scientists are stepping in to help. From floating chemical “sunscreens” to reef-patrolling robots, they’re developing all sorts of strategies and devices to help coral. In one of the most promising approaches, researchers are looking for ways to accelerate the pace at which corals adapt to warmer seas — so they can survive rather than succumb.

It’s too soon to know whether this approach will work...

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Colombia’s improbable reef offers hope for coral worldwide

The Varadero reef could offer clues for the survival of other reefs in contaminated areas

Just off the shore of the city of Cartagena, home of one of Colombia’s biggest ports, lies a coral reef that campaigners are furiously battling to protect. The Varadero reef, located in Cartagena Bay, has survived against the odds to thrive in a highly polluted environment. The Caribbean Sea bay, a major waterway for shipping vessels and cruise ships, is contaminated by industrial and sewage waste.

Shipping businesses are planning to expand the canal’s Bocachica Channel and build another passageway straight through the reef, meaning a quarter of it will be destroyed and the remainder threatened.

According to marine biologists, the reef should not be alive, and yet it has flourished, providing a home to a large number of coral, fish and urchin species.

‘Improbable and imperilled’

A report,...

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Heat Waves May Cause Fish to Flee Reefs

A school of fish swims in the Coral Sea

It’s no secret that global warming is bringing dramatic changes to coral reef ecosystems. Scientists have widely believed that habitat loss caused by coral death has the biggest effect on reef fish and invertebrates. Changes caused by warm water are actually faster and more widespread than the effects of habitat loss.Now new research has found that reef fish populations shift in direct response to the temperature itself and that changes caused by warm water are actually faster and more widespread than the effects of habitat loss.

The findings are significant for coral reef protection because a loss of biodiversity, especially of fish that eat harmful algae, could make it harder for reefs to recover from heat waves.

“I was surprised by how dramatic the response was over such a short time...

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How Gene Editing Could Save Coral Reefs

Bleached coral

The powerful gene-editing tool CRISPR-Cas9 is taking the scientific world by storm. It gives researchers unprecedented power and precision in making tweaks to practically any gene in a plant or animal — and coral reefs could become its next beneficiary.

In a paper published in the Proceedings of the National Academy of Sciences, researchers led by Phillip Cleves at Stanford University used CRISPR to edit three genes in corals growing in Australia’s Great Barrier Reef. Cleves manipulated the genes very early in the coral’s life cycle — just after fertilization of egg and sperm, when the coral is just one cell. That ensured that the genetic change was as widespread in the resulting coral’s genome as possible...

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