Marine Life & Conservation
Researchers Claim Dissolving Snail Shells Are An Effect of Ocean Acidification
An increasingly acidified Pacific Ocean is dissolving the shells of tiny marine snails that live along North America’s western coast. The broad finding, which has surprised some researchers, suggests that sea life is already being affected by changes in the ocean’s chemistry caused by rising carbon dioxide levels in the atmosphere.
“It really changes the game by demonstrating that acidification is having a noticeable impact,” says biological oceanographer Jan Newton, co-director of the Washington Ocean Acidification Center at the University of Washington, Seattle. Newton was not involved in the study.
The researchers studied one kind of pteropod, common planktonic snails known as sea butterflies for the winglike body parts that help them glide through the water. Like other shellfish, pteropods use dissolved carbonate in seawater to build their shells. But laboratory studies have shown that the process can be disrupted, and shells can dissolve as seawater becomes more acidic, or lower in pH (temperature has an impact, too). As its concentration rises in the atmosphere, carbon enters the ocean through chemical reactions, causing its pH at the surface to drop by 0.1 units since the pre-industrial era. That’s raised fears that marine ecosystems could be affected.
Outside the laboratory, however, just a handful of studies have linked falling pH levels to damaged shells. In 2012, researchers documented damage to oysters in hatchery tanks in Oregon fed with seawater that had become more acidic as a result of offshore upwelling patterns. The same year, researchers reported that pteropods collected at one site in the Southern Ocean around Antarctica showed signs of shell damage.
To gauge how acidification might be affecting the Pacific, biological oceanographer Nina Bednaršek of the National Oceanic and Atmospheric Administration (NOAA) in Seattle and colleagues collected pteropods at 13 sites during a 2011 research cruise between Washington and southern California. Back at the lab, they used a scanning electron microscope to examine the fragile shells, which are 1 cm in size or smaller. Normally, healthy pteropods have smooth shells. But more than one-half of these shells showed signs of dissolution, they report in the Proceedings of the Royal Society B. The pitted textures made them look like “cauliflower” or “sandpaper,” Bednaršek says.
“I was surprised by the sheer spacial extent of the dissolution,” she says. “This is something we have not predicted before – the extent of the population that’s already affected.”
What’s not clear from this study is how such damage might be affecting pteropod populations or the broader ecosystem. Previous work has suggested that shell damage can make it harder for the invertebrates to fight infection, maintain metabolic chemistry, defend themselves against predators, and control buoyancy. And while the snails are one of the most abundant organisms on Earth, “their role in ecosystems is generally not all that well known,” writes biological oceanographer Gareth Lawson of the Woods Hole Oceanographic Institution in Massachusetts in an e-mail. But “they can be important prey items at some times and places” for fish and other creatures. For example, the pteropod examined in this study, Limacina helicina, is a key food for fish eaten by pink salmon, an important North Pacific fishery.
“If the pteropod shells are dissolving as fast as the authors claim, the effects on individual physiology, behavior, and fitness, and hence on populations and food webs, are not easy to predict,” Lawson says. “But they could be profound.”
The waters probed during this study, known as the California Current, are a hot spot of ocean acidification because of coastal upwelling, which brings naturally acidic waters to the surface, where they are made even more acidic by greenhouse gas pollution. But Richard Feely of NOAA, a co-author on the study, says that the site serves as a “harbinger” for what global seas will be experiencing decades hence.
After a two-year tour of UK art galleries, community spaces and aquariums, the Shark Trust’s acclaimed Oceanic31 exhibition takes its final bow at the Royal Geographical Society later this month. And the unique collection of artwork, depicting 31 species of oceanic sharks and rays, donated by 31 artists, is now open for bids from art lovers and shark enthusiasts. The online auction, launched today, will close on the 7th December at 8pm (BST). The money raised will support the Shark Trust Oceanics Programme.
People can now bid on 27 of the artworks by visiting this website:
https://superstars-auctions.com/sharktrustauction
It is a chance to own a beautiful piece of original art and to support the Shark Trust. The timing of the auction also means that these would make a very special Christmas gift for any shark-lover.
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- Bigeye Thresher Shark by Janina Rossiter
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- Carcharodon carcharias by Jimmy Higgs
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- Croc VR 2030 by Tom Mead
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- Oceanic Whitetip by ATM
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- Silky Street by ScapaJoe
The diversity of pieces mirrors that of the sharks and rays they represent. You can bid on paintings, digital creations, sculptures, mixed media and more. You can pick your favourite artist or species of shark. Or you can select the perfect artwork to make a statement in your home or office. Whichever you choose, you will be supporting the work to protect these amazing animals.
One of the pieces of art has been selected to be auctioned live by Steve Backshall at the For the Love of Sharks event at the Royal Geographical Society in London on the 29th November. In addition to this, two further pieces will be raffled at this event, giving people a chance to win an incredible piece of shark art. For the Love of Sharks is the Shark Trust’s flagship evening. A night to celebrate sharks. Steve Backshall is the headline speaker at this event that will see other prominent shark advocates join him on stage.
Tickets for the event can be snapped up here:
https://thesharktrust.org.uk/Event/flos24
Those that would like to see the Oceanic 31 exhibition have one final chance. It is being displayed at the Pavilion at the Royal Geographic Society from 26th November until the 7th December. Entry is free.
Find out more here:
https://www.rgs.org/events/upcoming-events/oceanic-31
Paul Cox, Shark Trust CEO, Said “This exhibition has given us the opportunity to reach out to a new audience. And inspire more people with the wonderful sharks and rays on which our Big Shark Pledge campaign is based. We are immensely grateful to the 31 artists who have worked so hard to create these works.”
Bid for your favourite Oceanic 31 artwork here:
https://superstars-auctions.com/sharktrustauction
Banner Image: Smooth Hammerhead by Alicia Hayden
Until 28 November, prizes worth a massive £10,000 – including experiences, products and tuition – feature in a line-up of items that can be won for £5 in an online prize draw to celebrate Bite-Back Shark & Marine Conservation’s 20th anniversary and help generate crucial funds for the future.
Top of the list of prizes is the chance to spend time with adventurer and wildlife expert Steve Backshall, a workout session with Nat Geo star Aldo Kane, a kayaking trip alongside white-water expert and diver Sal Montgomery and a Zoom call with ‘shark whisperer’ Cristina Zenato.
On top of that, some of the most admired companies in the diving and scuba industry have been quick to support the charity with fabulous prizes that make the £5 ticket price worth more than just a flutter.
Master Liveaboards, BSAC, Midlands Diving Chamber, Go Freediving and Blue Shark Snorkel have all generously donated experience prizes, while celebrated photographer Alex Mustard has donated a print and artists Scott Gleed and Olivier Leger have donated a sculpture and illustration to help boost the fundraising pot.
Fourth Element has donated Ocean Positive gear and LA watch company Nodus has gifted the charity a stunning dive watch. For land lovers, the charity has included a five star London hotel stay at Bankside Hotel plus a family visit to Longleat Safari Park in the roster of prizes.
Campaign director for Bite-Back, Graham Buckingham, said: “We’ve been overwhelmed with support from companies and individuals that we truly admire and who have supported us on our 20 year journey and we’re truly grateful to them all. While we feel incredibly proud of our achievements over the past two decades – and we are super excited about the next chapter – this prize draw isn’t a vanity project. It represents a real lifeline to our work and important advancements in the global protection of sharks. So we hope divers, dive clubs and even bargain hunters grab some tickets to make this a massive success.”
The charity hopes that the prize draw will generate crucial funds to launch a brand new, ground-breaking, campaign to enrol the public and increase support for the protection of sharks around the world.
To enter the competition visit www.bite-back.com/prizedraw. The prize winners will be announced on 1 December 2024.
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