New study: History of climate change found in shellfish shells


HATTIESBURG, MS/ACCESSWIRE/August 29, 2022/ As parts of the Atlantic Ocean warm at an unprecedented rate, researchers are looking at past warming trends to help understand how past climate change has influenced marine life. A new study examines the fossil record of one of Earth’s oldest species to provide new insights into historic changes in climate and the impacts they have caused.

Published in the journal Holocene and funded by the Marine Fisheries Scientific Center (SCEMFIS), the study examines the fossil record of ocean quahogs to chart historical changes in ocean temperatures during the Holocene period, which spans the last 10,000 years of Earth’s history. Because there are no direct measurements of ocean temperatures for much of this time, indirect measurements, like the fossil record, can help reconstruct some of this history.

Ocean clams

Ocean quahogs in particular are useful for this type of reconstruction. They can only live in colder waters, below 16 degrees Celsius. Since much of the Northwest Atlantic is warmer than this, their habitat is currently restricted to lands that are part of the Mid-Atlantic Cold Pool, a recurring area of ​​bottom cold water in an area of the Atlantic known as the Mid-Atlantic Bight.

Since ocean quahogs prefer cold-basin waters to surrounding waters, the change in ocean quahog habitats over time can also serve as an indicator of changes in cold-basin and regional water temperatures over time. of the same period. Dating ocean quahog shells thus provides a history of climate change in the region.

The study accomplished this by collecting samples of ocean quahog shells from an area off the Delmarva Peninsula, close to the species’ current range, as well as live ocean quahogs from areas further afield. off New Jersey, Long Island and Georges Bank. The shells were radiocarbon dated to determine the approximate age when ocean quahogs were alive; radiocarbon dating of these animals ranged from 4,392 to 61 years old, with most sampled shells born in the early to late 1800s.

The study found that over the past 200 years, the Cold Pool has expanded both further south and closer to the coast than its current location. Changes in temperature, particularly warming, since the late 1800s caused the habitat range of the ocean quahog to shift away from these coastal areas during the 20th century. Looking more closely at the entire Holocene period, the distribution of ocean quahogs extended inshore during all previous cold periods, including more recently during the Little Ice Age, and retracted offshore during intermediate warm periods.

“This study gives us an important new tool to study past climate change in the Atlantic Ocean,” said Dr. Roger Mann of the Virginia Institute of Marine Science, one of the study’s authors. “Knowing how ocean quahogs have responded to ocean warming in the past gives us insight into how they will respond in the future.”

“For about 5,000 years, ocean quahogs have moved onshore and offshore at least 4 times in proportion to ocean warming and cooling,” said Dr Eric Powell, of the University of Southern Mississippi, another study author. “This study shows the potential of ocean quahogs to serve not only as a recorder of temperature change, but also as a tracker of species migration across the continental shelf in response to climate change, and demonstrates the resilience of this species over the long term. of life a changing climate.


SCEMFIS uses academic and fisheries resources to solve pressing scientific problems that limit sustainable fishing. SCEMFIS develops methods, analytical and survey tools, datasets and analytical approaches to improve the sustainability of fisheries and reduce uncertainty in biomass estimates. The academic partners of SCEMFIS, the University of Southern Mississippi (lead institution) and the Virginia Institute of Marine Science, College of William and Mary, are the academic sites. Collaborating scientists who provide specific expertise in fish, crustacean, and marine mammal research come from a wide range of academic institutions, including Old Dominion University, Rutgers University, University of Massachusetts- Dartmouth, University of Maryland and University of Rhode Island.

The need for the various services that SCEMFIS can provide to the industry continues to grow, which has resulted in a steady increase in the number of fishing industry partners. These services include immediate access to scientific expertise for stock assessment issues, rapid response to research priorities, and representation on stock assessment working groups. Targeted research leads to improvements in data collection, survey design, analytical tools, assessment models, and other needs to reduce uncertainty in stock status and improve endpoint objectives. reference.

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THE SOURCE: Marine Fisheries Scientific Center

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