Nav: Home

Modern mussel shells much thinner than 50 years ago

June 14, 2016

Shells of California mussels collected from the Pacific Ocean off the coast of Washington in the 1970s are on average 32 percent thicker than modern specimens, according to a new study published by University of Chicago biologists.

Shells collected by Native Americans 1,000 to 1,300 years ago were also 27 percent thicker than modern shells, on average. The decreasing thickness over time, in particular the last few decades, is likely due to ocean acidification as a result of increased carbon in the atmosphere.

"Archival material provided by past researchers, the Makah Tribal Nation, and the Olympic National Park allowed us to document this intriguing and concerning pattern in shell thickness," said Cathy Pfister, PhD, professor of ecology and evolution at the University of Chicago and lead author. The study was published June 15, 2016, in the Proceedings of the Royal Society B.

As humans burn fossils fuels, the oceans absorb a large portion of the additional carbon released into the atmosphere. This in turn causes pH levels of ocean water to drop, making it more acidic. Mussels, oysters, and certain species of algae have difficulty producing their calcium carbonate shells and skeletons in such an environment, and can provide an early indicator of how increasing ocean acidification affects marine life.

In previous studies, Pfister and her colleagues documented declining pH levels in the waters surrounding Tatoosh Island off the coast of Washington state. In 2011 they further analyzed carbon and oxygen isotopes taken from modern mussel shells, shells collected by the local Makah tribe between AD 668 and 1008, and shells collected by biologists in the 1970s.

For the new study, the researchers compared the thicknesses of the same sets of shells. On average, the shells provided by the Makah Cultural and Research Center were 27.6 percent thicker than modern counterparts. Shells from the 1970s were 32.2 percent thicker. Shells collected from a different Native American site in Sand Point, WA, dating between 2150 and 2420 years old were almost 94 percent thicker than modern shells.

The long-term decline in thickness likely shows a response to ocean acidification, though the researchers also consider other environmental drivers including changes in food supply (e.g. plankton) for mussels.

The researchers also point out that their findings raise concerns about the California mussel's ability to retain its role as a foundational species in these waters. Decreased shell thickness makes them increasingly vulnerable to predators and environmental disturbances. This in turn could affect interactions with hundreds of other species of organisms that live near mussel beds in tidal waters.

"The California mussel is a common species along the entire west coast of the United States, and their fate will be linked to that of a rich diversity of predators, including sea stars and sea otters, as well as myriad species that are part of the mussel bed habitat," Pfister said. "It is imperative that we understand more about how these species will change as ocean conditions change."
-end-
The study "Historical baselines and the future of shell calcification for a foundation species in a changing ocean," was supported by the SeaDoc Foundation, the National Science Foundation, and the United States Department of Defense. Additional authors include Timothy Wootton from the University of Chicago; Kaustuv Roy from the University of California, San Diego; Sophie McCoy, who conducted the work as a graduate student at UChicago, now at Florida State University; Robert Paine from the University of Washington; Thomas Suchanek from the US Geological Survey and the University of California, Davis; and Eric Sanford from the University of California, Davis.

About the University of Chicago Medicine and Biological Sciences

The University of Chicago Medicine & Biological Sciences is one of the nation's leading academic medical institutions. It comprises the Pritzker School of Medicine, a top 10 medical school in the nation; the University of Chicago Biomedical Sciences Division; and the University of Chicago Medical Center, which recently opened the Center for Care and Discovery, a $700 million specialty medical facility. Twelve Nobel Prize winners in physiology or medicine have been affiliated with the University of Chicago Medicine.

Visit our research blog at sciencelife.uchospitals.edu and our newsroom at uchospitals.edu/news.

Twitter @UChicagoMed, @ScienceLife
Facebook.com/UChicagoMed

University of Chicago Medical Center

Related Ocean Acidification Articles:

Ocean acidification could impair the nitrogen-fixing ability of marine bacteria
While increased carbon dioxide levels theoretically boost the productivity of nitrogen-fixing bacteria in the world's oceans, because of its 'fertilizing' effect, a new study reveals how increasingly acidic seawater featuring higher levels of this gas can overwhelm these benefits, hampering the essential service these bacteria provide for marine life.
International team reports ocean acidification spreading rapidly in Arctic Ocean
Ocean acidification (OA) is spreading rapidly in the western Arctic Ocean in both area and depth, according to new interdisciplinary research reported in Nature Climate Change by a team of international collaborators, including University of Delaware professor Wei-Jun Cai.
Unexpected result: Ocean acidification can also promote shell formation
Fact: more carbon dioxide (CO2) in the air also acidifies the oceans.
Ocean acidification to hit West Coast Dungeness crab fishery, new assessment shows
The acidification of the ocean expected as seawater absorbs increasing amounts of carbon dioxide from the atmosphere will reverberate through the West Coast's marine food web, but not necessarily in the ways you might expect, new research shows.
Landmark global scale study reveals potential future impact of ocean acidification
Ocean acidification and the extent to which marine species are able to deal with low pH levels in the Earth's seas, could have a significant influence on shifting the distribution of marine animals in response to climate warming.
Ocean acidification study offers warnings for marine life, habitats
Acidification of the world's oceans could drive a cascading loss of biodiversity in marine habitats, according to research published today in Nature Climate Change.
New study shows ocean acidification accelerates erosion of coral reefs
Scientists studying naturally high carbon dioxide coral reefs in Papua New Guinea found that erosion of essential habitat is accelerated in these highly acidified waters, even as coral growth continues to slow.
Study finds increased ocean acidification due to human activities
Oceanographers from MIT and Woods Hole Oceanographic Institution report that the northeast Pacific Ocean has absorbed an increasing amount of anthropogenic carbon dioxide over the last decade, at a rate that mirrors the increase of carbon dioxide emissions pumped into the atmosphere.
Ocean acidification threatens cod recruitment in the Atlantic
Increasing ocean acidification could double the mortality of newly hatched cod larvae.
First evidence of ocean acidification's impact on reproductive behavior in wild fish
Ocean acidification could have a dramatic impact on the reproductive behaviour of fish, a new international study shows.

Related Ocean Acidification Reading:

The Ocean of Life: The Fate of Man and the Sea
by Callum Roberts (Author)

Ocean Acidification: Understanding the Other Climate Crisis (Washington Journal of Environmental Law and Policy) (Volume 6)
by Washington Journal of Environmental Law and Policy (Author), Washington Journal of Environmental Law and Policy (Editor)

Ocean Acidification
by Jeanpierre Gattuso (Author), Lina Hansson (Contributor)

OCEAN ACIDIFICATION: Without Blue there is No Green
by Sivakumaran Sivaramanan (Author)

Ocean Acidification:A National Strategy to Meet the Challenges of a Changing Ocean
by National Academies Press

pH A Novel
by Nancy Lord (Author)

Acid-Base Balance and Nitrogen Excretion in Invertebrates: Mechanisms and Strategies in Various Invertebrate Groups with Considerations of Challenges Caused by Ocean Acidification
by Dirk Weihrauch (Editor), Michael O'Donnell (Editor)

Climate Change, Ocean Acidification and Sponges: Impacts Across Multiple Levels of Organization
by José Luis Carballo (Editor), James J. Bell (Editor)

State of the World's Oceans
by Michelle Allsopp (Author), Stefan E. Pambuccian (Contributor), Paul Johnston (Contributor), David Santillo (Contributor)

The Geopolitics of Deep Oceans
by John Hannigan (Author)

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".