Persian Gulf's coral reefs may holdclues to surviving climate change

This picture taken at Australia's Great Barrier Reef shows bleached branching coral in the foreground and normal

branching coral in the background. Photo: Acropora/Wikimedia Commons

The Persian Gulf's coral reefs only have 10 percent of the diversity found in the Indian

Ocean or on the Great Barrier Reef. But the murky waters off the United Arab Emirates

(UAE) coast might hold something even more precious: clues that could one day help

coral reefs around the world survive the effects of warmer waters caused by climate

change.

Most coral reefs in temperate climates can only withstand temperatures as high as 29

degrees Celsius (84 degrees Fahrenheit) before they expel the algae living in their tissue.

This "bleaching" process causes them to turn white. More importantly, it increases their

vulnerability to disease and death. The algae and coral have a symbiotic relationship —

the coral needs algae for food.

However, scientists have found corals in the Persian Gulf reefs that can tolerate water

temperatures as high as 36 degrees C (97 degrees F) — warmer than the highest

predictions for the next century. John Burt, a marine biologist at New York University, says

the Persian Gulf corals "offer hope." He thinks their genetic mechanisms could help other

corals survive warmer temperatures.

By Scientific American, adapted by Newsela staff on 03.09.15

Word Count 996

Climate Change On The Reefs

Pollution, overfishing and coastal development have cost coral reefs up to 50 percent of

their cover in some places. Still, most scientists say climate change poses the biggest

threat in the future.

Warming waters spark bleaching events. In addition, ocean acidification caused by

oceans absorbing carbon dioxide from the atmosphere (also blamed on climate change)

makes it harder for corals to calcify. Without enough calcium, their shells cannot grow

enough and thrive. The National Oceanic and Atmospheric Administration warned that

warming waters could lead to a global bleaching event in 2015 — the third one in the past

two decades.

Scientists believe most coral reefs will be under threat by 2040. They say corals and their

symbionts, which are single-celled algae, have been adapting too slowly to keep pace

with the rate of global warming.

Scientists studying the Persian Gulf are challenging this idea. They have shown that coral

reefs can bounce back from bleaching events faster than previously thought. They may

even be able to acquire heat-tolerant symbionts in a relatively short time. “It’s not all doom

and gloom for corals,” says Andrew Baker, a marine biologist at the University of Miami.

Adapting To Changing Conditions

Corals “have a repertoire of responses,” Baker says. “The question has been, well, how

quickly can those responses arise? I think we are now getting to this idea that actually, in

some cases, these mechanisms can arise very quickly, within a few years.”

Baker’s work prompted Burt and several of his peers to spend the last three years

surveying reef sites off the coasts of the UAE and Oman. They discovered a new type of

algae with heat-tolerant traits. Their research suggests that the heat tolerance in certain

corals and algae is unique to the Persian Gulf.

The researchers demonstrated that this new organism was the most commonly found

symbiont throughout the Persian Gulf. They say it likely adapted to play a new role in the

gulf’s harsh conditions, but they have not determined whether that happened by evolution

or if the algae was brought in by currents from outside the region and survived “a selection

process.”

“If they haven’t evolved in the gulf, they must be present in other populations in low

numbers elsewhere in the world," says University of Southampton professor Jörg

Wiedenmann. "This would be good news because that would mean corals elsewhere might

have these (heat) tolerant individuals among them.”

Answers May Lie Elsewhere

In theory, if symbionts exist elsewhere, then corals faced with bleaching could switch them

on as temperatures rise. "That could compensate for the some of the warming we are

expecting to see this century," Baker says. But he also notes that water temperatures are

predicted to climb beyond such tolerance. Scientists do not know if corals "can continue to

deal with increasing temperatures or whether this is a kind of a stopgap measure.”

Critics say it is foolish to think that any one element of a complex coral community will

provide a perfect solution. They are also doubtful about finding answers in the Persian

Gulf. Due to the gulf’s limited diversity and changing seasons, some experts think

researchers would be better off looking for answers in more temperate regions. Some have

suggested the Mozambique Channel between Tanzania and Madagascar. The corals there

have have bounced back from extreme bleaching events.

Reef expert Ove Hoegh-Guldberg says the Persian Gulf work is intriguing, but it was

“misplaced” to hope that the thermal tolerance would offer hope for reefs in temperate

climates. Evolution is too slow when it comes to “long-lived organisms such as corals.”

Guldberg also pointed out that the symbionts are not the only ones that need to evolve.

“It’s the combination of the host and symbiont that needs to adapt rapidly to changing sea

temperatures,” he wrote.

Reintroducing Corals Is Risky

Such doubts have done little to dampen the enthusiasm for using genes from the Persian

Gulf reefs in future conservation strategies.

Bernhard Riegl of Florida's Nova Southeastern University wants to begin moving corals to

the Indo-Pacific. He plans to introduce heat-adaptation through hybridization with resident

genetic material. Baker has considered introducing heat-tolerant symbionts in nurseries

and then reseeding areas at risk. Others want to crossbreed gulf corals with those in

temperate climates.

No one denies that these strategies involve risks — they are costly and could introduce

invasive species and disease. The reintroduced corals might not even cope well with new

environmental conditions.

But experts like the Australian Institute of Marine Science's Madeleine van Oppen argue

that it is time to explore human-assisted evolution. “When I first started talking about it,

people would say, ‘Oh God, that will never work. You can never do it at the scale

required,’” van Oppen wrote. “People still have those concerns, but they can see that it’s

important to develop the tools and to assess what is actually possible.”

Quiz

1 Select the paragraph from the section "Climate Change On The Reefs" that explains the

biggest problem facing coral reefs today.

2 Which paragraph from the article describes the important discovery highlighted in the article?

(A) Corals “have a repertoire of responses,” Baker says. “The question has

been, well, how quickly can those responses arise? I think we are now

getting to this idea that actually, in some cases, these mechanisms can arise

very quickly, within a few years.”

(B) Baker’s work prompted Burt and several of his peers to spend the last three

years surveying reef sites off the coasts of the UAE and Oman. They

discovered a new type of algae with heat-tolerant traits. Their research

suggests that the heat tolerance in certain corals and algae is unique to the

Persian Gulf.

(C) In theory, if symbionts exist elsewhere, then corals faced with bleaching

could switch them on as temperatures rise. "That could compensate for the

some of the warming we are expecting to see this century," Baker says. But

he also notes that water temperatures are predicted to climb beyond such

tolerance. Scientists do not know if corals "can continue to deal with

increasing temperatures or whether this is a kind of a stopgap measure.”

(D) Critics say it is foolish to think that any one element of a complex coral

community will provide a perfect solution. They are also doubtful about

finding answers in the Persian Gulf. Due to the gulf’s limited diversity and

changing seasons, some experts think researchers would be better off

looking for answers in more temperate regions. Some have suggested the

Mozambique Channel between Tanzania and Madagascar. The corals there

have have bounced back from extreme bleaching events.

3 Information from which of these sub-headings is LEAST important in understanding or shaping

the main idea of this article?

(A) "Climate Change On The Reefs"

(B) "Adapting To Changing Conditions"

(C) "Answers May Lie Elsewhere"

(D) "Reintroducing Corals Is Risky"

4 If this article were to be rewritten to focus on the risks associated with changing the natural

environment, which paragraph would be MOST useful?

(A) Such doubts have done little to dampen the enthusiasm for using genes

from the Persian Gulf reefs in future conservation strategies.

(B) Critics say it is foolish to think that any one element of a complex coral

community will provide a perfect solution. They are also doubtful about

finding answers in the Persian Gulf. Due to the gulf’s limited diversity and

changing seasons, some experts think researchers would be better off

looking for answers in more temperate regions. Some have suggested the

Mozambique Channel between Tanzania and Madagascar. The corals there

have have bounced back from extreme bleaching events.

(C) But experts like the Australian Institute of Marine Science's Madeleine van

Oppen argue that it is time to explore human-assisted evolution.

(D) Reef expert Ove Hoegh-Guldberg says the Persian Gulf work is intriguing,

but it was “misplaced” to hope that the thermal tolerance would offer hope

for reefs in temperate climates. Evolution is too slow when it comes to “long-

lived organisms such as corals.”

Answer Key

1 Select the paragraph from the section "Climate Change On The Reefs" that explains the

biggest problem facing coral reefs today.

Paragraph 4:

Warming waters spark bleaching events. In addition, ocean acidification caused

by oceans absorbing carbon dioxide from the atmosphere (also blamed on

climate change) makes it harder for corals to calcify. Without enough calcium,

their shells cannot grow enough and thrive. The National Oceanic and

Atmospheric Administration warned that warming waters could lead to a global

bleaching event in 2015 — the third one in the past two decades.

2 Which paragraph from the article describes the important discovery highlighted in the article?

(A) Corals “have a repertoire of responses,” Baker says. “The question has

been, well, how quickly can those responses arise? I think we are now

getting to this idea that actually, in some cases, these mechanisms can arise

very quickly, within a few years.”

(B) Baker’s work prompted Burt and several of his peers to spend the last

three years surveying reef sites off the coasts of the UAE and Oman.

They discovered a new type of algae with heat-tolerant traits. Their

research suggests that the heat tolerance in certain corals and algae is

unique to the Persian Gulf.

(C) In theory, if symbionts exist elsewhere, then corals faced with bleaching

could switch them on as temperatures rise. "That could compensate for the

some of the warming we are expecting to see this century," Baker says. But

he also notes that water temperatures are predicted to climb beyond such

tolerance. Scientists do not know if corals "can continue to deal with

increasing temperatures or whether this is a kind of a stopgap measure.”

(D) Critics say it is foolish to think that any one element of a complex coral

community will provide a perfect solution. They are also doubtful about

finding answers in the Persian Gulf. Due to the gulf’s limited diversity and

changing seasons, some experts think researchers would be better off

looking for answers in more temperate regions. Some have suggested the

Mozambique Channel between Tanzania and Madagascar. The corals there

have have bounced back from extreme bleaching events.

3 Information from which of these sub-headings is LEAST important in understanding or shaping

the main idea of this article?

(A) "Climate Change On The Reefs"

(B) "Adapting To Changing Conditions"

(C) "Answers May Lie Elsewhere"

(D) "Reintroducing Corals Is Risky"

4 If this article were to be rewritten to focus on the risks associated with changing the natural

environment, which paragraph would be MOST useful?

(A) Such doubts have done little to dampen the enthusiasm for using genes

from the Persian Gulf reefs in future conservation strategies.

(B) Critics say it is foolish to think that any one element of a complex coral

community will provide a perfect solution. They are also doubtful about

finding answers in the Persian Gulf. Due to the gulf’s limited diversity and

changing seasons, some experts think researchers would be better off

looking for answers in more temperate regions. Some have suggested the

Mozambique Channel between Tanzania and Madagascar. The corals there

have have bounced back from extreme bleaching events.

(C) But experts like the Australian Institute of Marine Science's Madeleine van

Oppen argue that it is time to explore human-assisted evolution.

(D) Reef expert Ove Hoegh-Guldberg says the Persian Gulf work is

intriguing, but it was “misplaced” to hope that the thermal tolerance

would offer hope for reefs in temperate climates. Evolution is too slow

when it comes to “long-lived organisms such as corals.”