Please select your home edition
Edition
GAC Pindar Sailing News

Marine snails being dissolved by ocean acidification

by British Antarctic Survey on 28 Nov 2012
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 http://www.antarctica.ac.uk/
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.

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 British Antarctic Survey website

Harken and Fosters -  Harken WinchesAbsolute MarineGold Coast Marine Expo 2017 660x82

Related Articles

Vibrant Life in Northern sector of the Great Barrier Reef
If you're curious about state of Great Barrier Reef north of Cairns, dive into world of Cairns local, Jemma Craig. If you're curious about the state of the Great Barrier Reef north of Cairns, take a minute to dive into the world of Cairns local, Jemma Craig.The 24-year old took the chance to document her first scuba dive on the reefs surrounding Raine Island, an area reported last year as being severely affected by coral bleaching.
Posted on 20 Jan
The Deepwater Horizon aftermath
Researchers analyze 125 compounds from oil spilled in Gulf of Mexico to determine their longevity at different levels. Researchers analyze 125 compounds from oil spilled in the Gulf of Mexico to determine their longevity at different contamination levels. The oil discharged into the Gulf of Mexico following the explosion and sinking of the Deepwater Horizon (DWH) rig in 2010 contaminated more than 1,000 square miles of seafloor.
Posted on 1 Jan
What happened to Deepwater Horizon Oil?
What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Six years after the Deepwater Horizon oil spill, we are continually asked two questions. What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Was discharging 1.67 million gallons of chemicals into the ocean to disperse the oil a good or bad idea?
Posted on 24 Dec 2016
Great Barrier Reef managers and industry prepare for summer
Marine park managers, scientists and experts recently met for the annual pre-summer workshop Marine park managers, scientists and experts recently met for the annual pre-summer workshop to assess climate-related risks to the Great Barrier Reef over the coming months. Current predictions by the Bureau of Meteorology and National Oceanic and Atmospheric Administration are for a summer of average sea temperatures across the Great Barrier Reef.
Posted on 7 Dec 2016
Introducing the Airbnb of the mooring and marina world
Have you ever struggled to find an available mooring, or do you have a mooring that is sitting vacant? Have you ever struggled to find an available mooring, or do you have a mooring that is sitting vacant? makefastmooring.com is aiming to solve this problem by connecting boat owners with those with vacant moorings or berths. With a growing number of moorings and marinas in New Zealand, Australia and around the world, makefastmooring.com allows people to find, rent and share moorings and berths.
Posted on 7 Dec 2016
Princess to pay largest ever criminal penalty for vessel pollution
Princess Cruise Lines has agreed to plead guilty to seven felony charges stemming from deliberate pollution of the seas Princess Cruise Lines Ltd. (Princess) has agreed to plead guilty to seven felony charges stemming from its deliberate pollution of the seas and intentional acts to cover it up. Princess will pay a $40 million penalty– the largest-ever criminal penalty involving deliberate vessel pollution – and plead guilty to charges related to illegal dumping of oil contaminated waste from the cruise ship.
Posted on 2 Dec 2016
Race for Water catamaran to be equipped with new hydrogen system
Race for Water will make it possible for the crew to free themselves of the need for fossil fuels during new mission. Race for Water will make it possible for the crew to completely free themselves of the need for fossil fuels during the new mission against the pollution of the oceans.
Posted on 26 Nov 2016
Radio spectrum changes have been put into place in New Zealand
New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels to make space for newly allocated international services for ship tracking and data services. On the October 1st, New Zealand moved a few private VHF repeater services, most Coastguard VHF repeater services, and all NowCasting weather services. An updated radio handbook and freq
Posted on 2 Nov 2016
Operation Retune underway in remote corners of New Zealand
Radio technicians have been working at sites for the Maritime VHF channel changes Radio technicians have been working at sites for the Maritime VHF channel changes The scenery is spectacular but getting to transmitters sites in New Zealand can be a challenge for radio technicians working on the Maritime VHF change over.
Posted on 4 Oct 2016
Skies clear for final day of the Auckland On the Water Boat Show
Heavy rain which hit the Auckland On the Water Boat Show has cleared and it is business as usual The heavy rain which hit the Auckland On the Water Boat Show and the rest of the province has cleared and it is business as usual for the final day. The crowds were at the Viaduct Events Centre gat at 10.00am this morning - a little surprising given the heavy rain which has plagued Auckland over night and at Show opening time, plus the All Blacks Test match which started at 11.00am.
Posted on 1 Oct 2016