Subscribe to our free daily newsletters
. Earth Science News .

Subscribe to our free daily newsletters

Cold-water corals: Acidification harms, warming promotes growth
by Staff Writers
Kiel, Germany (SPX) May 03, 2017

illustration only

Because they build their skeletons from calcium carbonate, cold-water corals such as the globally distributed species Lophelia pertusa are considered particularly threatened by ocean acidification. This change in seawater chemistry, caused by the absorption of carbon dioxide (CO2) from the atmosphere, reduces the concentration of carbonate ions.

With fewer carbonate ions, calcification becomes more difficult. However, laboratory studies at GEOMAR Helmholtz Centre for Ocean Research Kiel reveal, that a simultaneous increase in water temperatures could help Lophelia pertusa to counteract negative effects of ocean acidification.

The experiments that were conducted as part of the German research programme on ocean acidification BIOACID (Biological Impacts of Ocean Acidification) demonstrate how important it is to investigate Lophelia's response to single drivers of climate change as well as their combined effects.

On an expedition with the research vessel POSEIDON and the submersible JAGO, marine biologists from GEOMAR collected corals at Trondheim Fjord (Norway) for their investigations.

"During our JAGO dives, we examined the condition of the reefs. We documented their expansion and the diverse community living in the reefs and carefully chose our samples", explains Janina Buscher.

The PhD student from the department of Biological Oceanography at GEOMAR conducted the experiments and is lead author of a publication on the effects and impact of ocean acidification and warming on the growth and fitness of Lophelia pertusa in the research journal Frontiers in Marine Science.

"The richness in species of these reefs that exist in almost complete darkness and at temperatures below ten degrees Celsius is very impressive." Many of these underwater oases, grown over centuries, are protected as natural heritages. Their diversity ensures the resilience of the fjord ecosystem, and many species of fish find shelter and food in the reefs.

To find out more about the future of the corals, the biologists from Kiel kept Lophelia pertusa colonies at the GEOMAR laboratories for six months. The water in some of the test aquaria was held at eight degrees Celsius just like in the Norwegian reef, others were elevated to twelve degrees.

The CO2 concentration was either set to the current values of 400 micro-atmospheres or to 800 micro-atmospheres, which are expected for the end of this century. In addition, the amount of food was altered. Some of the corals received ten times as much food than those in the respective control treatments.

Monthly measurements and final analyses showed: Under more acidified conditions and unchanged temperatures, the corals grew slower, regardless of the food supply. But when acidification was combined with elevated temperature, they developed at about the same rates as under today's CO2 concentrations and water temperatures. The tenfold increase in food supply benefitted the corals only if just one of the parameters was increased.

When both parameters were changed, they seemed to be unable to take up the additional food. "The elaborate experimental setup shows that when applied in combination, different climate change drivers can interact in their effects on the corals. While in this specific case they compensated each other, at higher temperatures they may amplify each other, as we know from studies on other calcifying organisms", says Janina Buscher.

Depending on the extent at which the ocean acidifies in the course of climate change and which water temperatures the corals experience, their overall reaction could be less neutral than observed in the experiment, the GEOMAR team assumes.

In addition, other factors not investigated so far, such as eutrophication and pollution, can further amplify the corals' sensitivity to climate change. Another cause for concern is that the unprotected lower parts of the Lophelia stocks, which form the foundation of the reefs, are directly exposed to seawater and can therefore be corroded by acidifying waters.

"In our experiments we have seen how flexible Lophelia pertusa reacts and how different factors influence each other. The fact that they are able to attenuate each other under certain conditions could be reason for hope. But we know far too little to give an all-clear", says Janina Buscher.

Currently, the researchers are trying to identify critical thresholds for acidification and warming based on recent studies. They suspect that Lophelia pertusa will only benefit from rising temperatures as long as they stay within the limits that this species is currently experiencing in its distributional range.

In many regions, however, they are already at their temperature limit. If temperatures continue to rise, the compensatory effect observed in this study could turn negative, amplifying the effect of ocean acidification.

Despite many questions remaining unanswered, the scientists urge: "If we wait for more detailed insights before we mitigate climate change, it may be too late to preserve the cold-water coral reefs."

Buscher, J.V., Form, A.U. And Riebesell, U. (2017): Interactive Effects of Ocean Acidification and Warming on Growth, Fitness and Survival of the Cold-Water Coral Lophelia pertusa under Different Food Availabilities. Frontiers in Marine Science 4: 101. doi: 10.3389 / fmars.2017.00101

Vinegar offers hope in Barrier Reef starfish battle
Sydney (AFP) April 27, 2017
Coral-munching crown-of-thorns starfish can be safely killed by common household vinegar, scientists revealed Thursday in a discovery that offers hope for Australia's struggling Great Barrier Reef. The predatory starfish is naturally-occurring but has proliferated due to pollution and run-off at the World Heritage-listed ecosystem, which is also reeling from two consecutive years of mass cor ... read more

Related Links
Helmholtz Centre for Ocean Research Kiel
Water News - Science, Technology and Politics

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Zapping bacteria with sanitizers made of paper

Researchers develop radar simulator to characterize scattering of debris in tornadoes

US opioid crisis at epidemic proportions

Bullying is on the decline in most schools, new research shows

Why space dust emits radio waves upon crashing into a spacecraft

Ground Control Satellite Dish Arrives at University of Leicester

Raytheon receives $327M radar contract for U.S. Navy

SES Offers Panoramic Glimpse into the Future of TV with Live Virtual Reality Demo

Cold-water corals: Acidification harms, warming promotes growth

Norway billionaire reveals plan to give away his fortune

Some corals adapting to warming climate

New coral bleaching database to help predict fate of global reefs

Canada: walrus, caribou face extinction risk in Arctic

Antarctic Peninsula ice more stable than thought

Warm winds: New insight into what weakens Antarctic ice shelves

New atlas provides highest-resolution imagery of the Polar Regions seafloor

Researchers track impact of Brazil's 'Soy Moratorium'

Scientists say agriculture is good for honey bees

Common pesticide damages honey bee's ability to fly

Urban farming flourishes in New York

Earthquakes can make thrust faults open violently and snap shut

6.8-magnitude quake strikes the Philippines: USGS

New model could help predict major earthquakes

Hard rocks from Himalaya raise flood risk for millions

Rocket attack on UN camp in Mali kills one, wounds 9

Congolese plantation sprouts art centre to help the poor

US Defense Secretary Mattis visits strategic Djibouti

Top conservationist wounded in Kenya gun attack

Brazil's indigenous leader Raoni: youths losing their culture

Population growth, spread responsible for human advancement

Early evidence of Middle Stone Age projectiles found in South Africa's Sibudu Cave

Bonobos may be better representation of last common ancestor with humans

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement