>
 
> FishingBoating-World.com
 
 
News Home Newsletters Powerboat-World Australian Cruising World Cruising MarineBusiness-World Animated Knots Video Gallery
MarineBusiness-World Photo 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.fishingboating-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.







FishingBoating-World





Pontoon Boats are a hit with families and entertainers by Sanctuary Cove International Boat Show,
















Glacier Bay returns to Australia, re-launching at SCIBS by Sanctuary Cove International Boat Show,
















Power to the people at Sanctuary Cove International Boat Show by Sanctuary Cove International Boat Show,






























Humpback Whales - Non Lethal research
VRFish works with fishers on Corio Bay conflict
Changed boating conditions for ski race on Clarence River
VRFish calls for action on Anglesea River
Submit your entry to the BoatUS Angler 'Catch of the Month' contest
Channel 7 stage returns to Sanctuary Cove International Boat Show
Brisbane Tinnie & Tackle Show - this weekend!
Coastal infrastructure and species loss - Climate Change consequences *Feature
rescueME PLB1 – safety assured in one compact, light package *Feature
Japan's Antarctic whaling program harpooned
All Marine Spares hits the boat show trail in a trailer *Feature
Macquarie perch stocked into three northern Victorian waters
Local council celebrates commitment to protect the Great Barrier Reef
Go crazy about whales in a special family fun day at the museum
New generation trawler boats - tradition with a twist
Arvor releases new Sportsfish range
AIMEX focuses on commercial show in Asia
Further Australian growth for Stabicraft
Southport Yacht Club will host a free 'Discover Sailing Day'
Melbourne Boat Show earlier this year - 12 to 16 June
FinScan digital switching fitted to new rescue vessels   
Kids' Zone a drawcard at Brisbane Tinnie & Tackle Show   
Brisbane Tinnie & Tackle welcomes Engel as stage sponsor   
BIAV appoints new GM   
Jet stream gets fish in hot water   
Trash to Treasure - A seafood story   
Big waves shown to be energetically costly for fish   
Fisherman nabbed for illegal fishing at Point Lonsdale   
Maritime Alert - Dangerous conditions forecast for NSW boaters   
World Recreational Fishing Conference - First call for papers open   
12 weeks til Melbourne Boat Show   
First deadline for SCIBS exhibitors looms March 24   
Fishing for Culture - A celebration of fishing in culture   
Improving fish habitat by building a fishing line recycling bin +Video   
Greater numbers of catchable King George whiting in the years to come   
Paul Burt, boating guru, is the face of Sanctuary Cove Boat Show   
Marine Industry loses a loyal servant: Vale Gunter Bruckner   
Positive pass mark for new venue   
Couran Cove signs lease deal with Hope Island Marina   
Phones outpace PCs and TV as preferred device   


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 FBW