. Earth Science News .

Heat and cold damage corals in their own ways
by Staff Writers
San Diego CA (SPX) Feb 09, 2012

File image.

Around the world coral reefs are facing threats brought by climate change and dramatic shifts in sea temperatures. While ocean warming has been the primary focus for scientists and ocean policy managers, cold events can also cause large-scale coral bleaching events.

A new study by scientists at Scripps Institution of Oceanography at UC San Diego compared damage to corals exposed to heat as well as cold stress. The results reveal that cool temperatures can inflict more damage in the short term, but heat is more destructive in the long run.

The study is published in Scientific Reports, a publication of the Nature Publishing Group.

Climate change is widely known to produce warming conditions in the oceans, but extreme cold-water events have become more frequent and intense as well. In 2010, for example, coral reefs around the world faced one of the coldest winters and one of the hottest summers on record.

During a unique experiment conducted by former Scripps Oceanography student Melissa Roth and current Scripps scientist Dimitri Deheyn, corals subjected to cold temperatures suffered greater growth impairment and other measurable damage in just days compared with heat treated corals.

Yet the researchers found that corals were eventually able to adjust to the chilly conditions, stabilize their health and continue to grow. However, over the long term corals subjected to heat suffered more greatly than those in cold, with evidence of severe bleaching and growth stoppage, a trajectory that leads to death.

"These results show distinct responses between cold and heat-treated corals on different time scales," said Roth, now based at Lawrence Berkeley National Laboratory.

"On a short time scale, the cold event was actually more harmful to the corals than an equivalent warming event, but over time, these corals were able to acclimate to the cold. Therefore, these corals showed more resilience to seawater cooling than seawater warming."

The coral's ability to adjust to cool temperatures surprised the researchers, who say the study's results highlight the complexities of monitoring coral health in response to varying environmental factors.

During the investigations-conducted inside Scripps' Experimental Aquarium-the researchers tracked the overall coral health and the stress of their symbiotic algae, sometimes called "zooxanthellae."

The symbiosis is an essential component for reef-building corals because the symbionts provide corals with most of their energy. Accordingly, the researchers found that the cold both disrupted the photosynthetic system of the symbionts and greatly reduced coral growth.

"Global warming is associated with increases but also decreases of temperatures," said Deheyn, a project scientist in Scripps' Marine Biology Research Division.

"Not much has been known about the comparative effects of temperature decrease on corals. These results are important because they show that corals react differently to temperature differences, which is critical for future management of coral reefs in the realm of climate change."

Related Links
University of California - San Diego
Water News - Science, Technology and Politics

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries


. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

UNH Ocean Scientists Shed New Light on Mariana Trench
Durham NH (SPX) Feb 09, 2012
An ocean mapping expedition has shed new light on deepest place on Earth, the 2,500-kilometer long Mariana Trench in the western Pacific Ocean near Guam. Using a multibeam echo sounder, state-of-the-art equipment for mapping the ocean floor, scientists from the University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center found four "bridges" spanning the trench and ... read more

Top US general meets Egypt's Tantawi amid NGOs row

Bird numbers drop around Fukushima

Japan passes $33 bln fourth extra budget

UN aims for major cut in peacekeeping bill

Russia to build powerful laser facility

Northrop Grumman Delivers 25,000th Electro-Optic Laser System to U.S. Army

Iran Launches New Home-Made Satellite into Orbit

Ailing Kodak shutters its camera operations

Google Earth Ocean Terrain Receives Major Update

Heat and cold damage corals in their own ways

UNH Ocean Scientists Shed New Light on Mariana Trench

Hundreds of dead dolphins wash ashore in Peru

CU-Boulder study shows global glaciers, ice caps, shedding billions of tons of mass annually

Putin receives 'prehistoric' water from Antarctic lake

Himalayan meltdown not so fast after all: study

First plants caused ice ages

Valentine's flowers inspected for pests

Chinese snap up Aussie vines in hunt for top drop

Miami battling invasion of giant African snails

Romania's incoming agriculture minister slammed for GM links

Tree rings may underestimate climate response to volcanic eruptions

Chile to prosecute workers over lack of tsunami warning

Death toll in Philippine quake rises to 39

N.Z. quake building was sub-standard: probe

Inter-ethnic fighting displaces 40,000 in Kenya

Mali army tries to fend off Tuareg rebels as crisis grows

Chinese, Russian arms fuel Darfur abuse: Amnesty

Explosion rocks military barracks in northern Nigeria

Neanderthal demise due to many influences, including cultural changes

Why the brain is more reluctant to function as we age

Cutting-edge MRI techniques for studying communication within the brain

Entire genome of extinct human decoded from fossil

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: 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 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal 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. 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