sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
Sail-World.com : Marine snails being dissolved by ocean acidification
Marine snails being dissolved by ocean acidification

'The pteropod (marine snail) Limacina helicina antarctica which is abundant member of the Southern Ocean zooplankton community. Specimens mainly inhabit the top 200 m of oceanic waters where they graze on phytoplankton and detritus. Their shells are made of aragonite, a form of calcium carbonate that can dissolve rapidly.'    Nina Bednarsek

The shells of marine snails – known as pteropods – living in the seas around Antarctica are being dissolved by ocean acidification according to a new study published this week in the journal Nature Geoscience. These very small animals are a valuable food source for fish and birds and play an important role in the oceanic carbon cycle*.

During a science cruise in 2008, researchers from British Antarctic Survey (BAS) and the University of East Anglia (UEA), in collaboration with colleagues from the US Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration (NOAA), discovered severe dissolution of the shells of living pteropods in Southern Ocean waters.

The team examined an area of upwelling, where winds cause cold water to be pushed upwards from the deep to the surface of the ocean. Upwelled water is usually more corrosive to a particular type of calcium carbonate (aragonite) that pteropods use to build their shells. The team found that as a result of the additional influence of ocean acidification, this corrosive water severely dissolved the shells of pteropods.

Ocean acidification is caused by the uptake of carbon dioxide from the atmosphere emitted as a result of fossil fuel burning. A number of laboratory experiments have demonstrated the potential effect of ocean acidification on marine organisms. However, to date, there has been little evidence of such impacts occurring to live specimens in their natural environment. The finding supports predictions that the impact of ocean acidification on marine ecosystems and food webs may be significant.

RRS James Clark Ross in the Bellingshausen Sea, west of the Antarctic Peninsula -  British Antarctic Survey ©  
Lead author, Dr. Nina Bednaršek, formerly of BAS and UEA, and now of the National Oceanic and Atmospheric Administration (NOAA) says:

'We know that the seawater becomes more corrosive to aragonite shells below a certain depth — called the ‘saturation horizon’ — which occurs at around 1000m depth. However, at one of our sampling sites, we discovered that this point was reached at 200m depth, through a combination of natural upwelling and ocean acidification. Marine snails – pteropods — live in this top layer of the ocean. The corrosive properties of the water caused shells of live animals to be severely dissolved and this demonstrates how vulnerable pteropods are. Ocean acidification, resulting from the addition of human-induced carbon dioxide, contributed to this dissolution. '

Co-author and science cruise leader, Dr. Geraint Tarling from BAS, says:

'Although the upwelling sites are natural phenomena that occur throughout the Southern Ocean, instances where they bring the ‘saturation horizon’ above 200m will become more frequent as ocean acidification intensifies in the coming years. As one of only a few oceanic creatures that build their shells out of aragonite in the Polar Regions, pteropods are an important food source for fish and birds as well as a good indicator of ecosystem health. The tiny snails do not necessarily die as a result of their shells dissolving, however it may increase their vulnerability to predation and infection consequently having an impact to other parts of the food web.'

Co-author, Dr. Dorothee Bakker from the University of East Anglia, says:

'Climate models project a continued intensification in Southern Ocean winds throughout the 21st century if atmospheric carbon dioxide continues to increase. In turn, this will increase wind-driven upwelling and potentially make instances of deep water — which is under-saturated in aragonite – penetrating into the upper ocean more frequent. Current predictions are for the ‘saturation horizon’ for aragonite to reach the upper surface layers of the Southern Ocean by 2050 in winter and by 2100 year round. '

This research was funded by the UK Natural Environment Research Council (NERC) and the European Union Marie Curie Early Stage Training Network.

*Carbon cycle - the method by which carbon is absorbed and released by the ocean.

Upwelling: An oceanographic phenomenon that involves wind-driven motion of cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water.

Aragonite is a crystal form of calcium carbonate that can dissolve rapidly when its saturation in seawater falls below a threshold level. Aragonite saturation generally decreases with depth and the threshold level where dissolution occurs, called the ‘saturation horizon’, is usually reached at around 1000m depth. Ocean acidification has caused this horizon to shallow in modern times. It has been predicted that the saturation horizon may reach the surface across much of the Southern Ocean by 2100.

The pteropod-snail (Limacina helicina antarctica) – is the size of a pinhead (1cm), lives to depths of 200m, and is an abundant species in Southern Ocean waters.

Polar Regions are where ocean acidification effects are most likely to be seen first, since their colder temperatures mean a large susceptibility of the aragonite saturation to the absorption of anthropogenic carbon dioxide.

British Antarctic Survey website


by British Antarctic Survey

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=104167

8:24 PM Tue 27 Nov 2012GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.







News - USA and the World

























Lightning strikes cut short CFJ Nationals by Andy Kopetzky, Santa Monica Bay


















America's Cup: Group agrees to co-operate in London Meeting by Richard Gladwell/Sail-World.com/nz,












America's Cup: Alameda makes overtures on Venue hosting for San Fran *Feature by Richard Gladwell/Sail-World.com/nz,












ISAF World Sailing Rankings for 28 July 2014
29er World Championship - All set in Kingston
ORC World Championship - Third Course area opens for huge fleet
Day one of the Allen RS Feva World Championships
Anna Tunnicliffe On the Final two days of the Reebok CrossFit Games
Joachim Aschenbrenner takes gold at ISAF Youth Match Race Worlds 2014
Maxi Soh scores double wins in CMRC Summer Doubleheader
29er World Championship opening ceremonies in Confederation Park
PWA Fuerteventura Grand Slam - Action resumes on day 3
Land Rover Sydney Gold Coast Yacht Race Start 2014 VIDEO
Laser Radial Men’s World Championship 2014- Final day
2014 Pacific Cup - Scarlet Runner wins
Gladwell's Line: America's Cup - Joint Statement is a curious note *Feature
ISAF Youth Match Racing World Champ - Top four battle it out for final
BIC Techno 293 Worlds 2014 - Day 6
PWA Fuerteventura Grand Slam - Wind teases competitors on day 2
Women’s Match Race Golfe du Morbihan - Action-packed day of racing
Herreshoff Marine Museum announces successful fundraising campaign
Brewin Dolphin Commodores' Cup - The most comprehensive victory yet
Anna Tunnicliffe holds fourth at mid-point of Reebok CrossFit Games
2014 29er North American Open Championship - Australians win   
INSA Sabot II Invitational Regatta - Erik Hou claims victory   
CMRC Summer Invitational Series - Maxi Soh wins Doubleheader A event   
International Moth World Championships - Nathan Outteridge wins   
PWA Fuerteventura Grand Slam - First blood to Toselli and Angulo   
Melges 24 Nationals - Record entries for 2014 and 2015 venue revealed   
Women’s Match Race Golfe du Morbihan - Anna Kjellberg claims the lead   
Jessica Uniack Memorial Beach to Bay Race at Long Beach YC   
Laser Radial Men’s World Championship - Poland tops the leaderboard   
America's Cup - Four teams confirm full support regardless of venue   
Plastic Classic takes place at Mariposa Hunters Point YC   
Six Metre European Championship - No champion declared for 2014   
J/Teams sail tough Chicago Mackinac Race   
Anna Tunnicliffe wins first event of Reebok Cross Fit Games + Video   
2014 Pacific Cup - Skill and luck required for victory   
Six Metre European Championship - Action resumes on day 4   
BIC Techno 293 Worlds 2014 - Day 4   
PWA Fuerteventura Grand Slam on the horizon   
Rolex Big Boat Series - Golden Jubilee to take place this September   
DH Pacific Cup - Running with the pack + Video   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW US
LocalAds   DE  ES  FR  IT