Limpets, crabs stressed by higher temperatures, acidity

• News Home
• More from News of the North

Thursday, September 21, 2023 at 6:43 PM

• Share on Facebook
• Share on Messenger
• Share on Messenger
• Share on X
• Share on Whatsapp

Fairbanks, Alaska (UAF) - Warmer, more acidified water increases stress in a species of limpet in Alaska’s Kachemak Bay, a University of Alaska Fairbanks graduate student has found.

Shelby Bacus’ discovery, along with her ongoing study of Bering Sea crabs, adds to the scientific understanding of how much environmental change marine species can tolerate.

In a recently published paper, Bacus and associate professor Amanda Kelley, both at the UAF College of Fisheries and Ocean Sciences, described the responses of Pacific plate limpets to temperatures and pH levels matching a future worst-case climate warming scenario.

Pacific plate limpets, named for their flattened, cone-shaped shell over a suction-cup foot, graze upon algae in Kachemak Bay’s rocky intertidal zone.

They regulate the growth of algae, which can limit the ability of other organisms to grow or establish themselves in the zone.

In Bacus’ experiments, the limpets showed increased cortisol levels and metabolic rates — both signs of stress — when exposed to increased temperatures and lowered pH levels.

Increased stress makes it more difficult for organisms to maintain normal functions, growth, or reproduction.

Previous studies have found that many marine species that have acclimated to higher temperatures develop an increased range of tolerance to higher temperatures.

Bacus’ limpets reacted somewhat differently to exposure to warmer water.

She found that limpets that had been acclimated to warmer water for 90 days had a lower tolerance to further increasing temperatures than did limpets that had remained in present-day temperatures.

However, limpets that had been exposed to both warmer water and lowered pH had the least tolerance of even higher heat and lower pH, Bacus found.

Bacus exposed the limpets to the worst-case temperatures and pH levels forecast for 2100 by the Intergovernmental Panel on Climate Change in its Representative Concentration Pathway 8.5 scenario.

That’s a global mean sea surface temperature increase of 4 degrees Celsius from a pre-industrial age baseline and a 0.4 unit decrease in ocean surface pH (about a 150 percent increase in ocean acidification).

As an undergraduate student at the University of California Davis, Bacus previously studied another type of gastropod — intertidal snails.

In those studies, lower pH levels rendered the snails incapable of responding to predators, probably because the acidified environment interfered with neurochemical pathways.

But Pacific plate limpets’ responses to predators were only slightly affected by lower pH, Bacus found.

Limpets hold tenaciously upon rocks, but when they sense the presence of a predator such as the mottled sea star, they respond by wobbling or spinning.

Bacus is now studying the effects of temperature and pH on Tanner and snow crabs in the Bering Sea.

Both species have supported large commercial fisheries.

The Bering Sea snow crab fishery closed for the first time last fall following a massive snow crab die-off event.

The Tanner crab fishery has since reopened in some sections but remains closed in others.

Although her crab research is not yet complete, Bacus is observing similar responses in metabolic stress to that of the snails and limpets.

Warmer temperatures and lower pH appear to have mixed effects on Tanner crab growth rates.

Snow crabs, however, were highly vulnerable to the combination of increased heat and decreased pH in her experiments, she found.

Bacus gathered data on crab population size this past summer with the National Oceanic and Atmospheric Administration’s bottom trawl surveys.

To see updates on Bacus and Kelley’s ocean acidification research, follow the Kelley Lab on social media.

More from News of the North

• Jeanne Bitz's story — healing through Hawai'i

  Juneau, Alaska (KINY) - Jeanne Bitz is a painter and sculptor in Maui, Hawai'i.

• Alaska Athletes Will Push Their Limits in IRONMAN Alaska

  Juneau, Alaska (KINY) - On Sunday one of the hardest athletic events around the world will begin on the shores of Auke Lake in Juneau with a cannon blast that will signify the first official full IRONMAN race in Alaska.

• Juneau Skating Club Spring Show a Musical Ice Delight

  Juneau, Alaska (KINY) - If you don’t have a ticket to today’s Juneau Skating Club Spring Show at Treadwell Ice Arena then pay at the door or beg to get in as this is a show you will not want to miss!

• Crimson Bears & Falcons Go Purple to Raise Suicide Awareness & Prevention

  Juneau, Alaska (KINY) - The Juneau-Douglas High School: Yadaa.at Kalé and Thunder Mountain High School basketball teams, coaches, cheerleaders and officials will wear purple during their games tonight and Saturday night at the JDHS gym to raise awareness for mental health, suicide prevention and positive messaging for young adults and community members.

• Pep Band Spices Up Local Sports

  Juneau, Alaska (KINY) - It takes something special to supplement a high caliber activity without taking away from that activity and that challenge has been met every basketball season by the pep bands of Thunder Mountain High School and Juneau-Douglas High School: Yadaa.at Kalé.

• Photos: Perseverance Trail Landslide

  The recent avalanche and landslide activity in the Basin Road and Perseverance Trailhead area is shown in these photos from KINY.

• Crimson Bears Butt Heads with Moose on Ice

  Juneau, Alaska (KINY) - The Juneau-Douglas High School Yadaa.at Kalé Crimson Bears hockey team fell by the score of 4-2 to the Palmer Moose on Monday night at Treadwell Arena in a spirited and physical Railbelt Conference battle around the rink.

• Juneau's High School Hoopsters and Skaters Can Unmask

  The Juneau School District is allowing their high school basketball and hockey players to play unmasked if certain testing requirements are met. Juneau School District Superintendent Bridget Weiss noted that the change only applies to players who are actively participating in one of the two sports and that coaches and athletes seated on the bench still have to wear face coverings.

• First Things First Alaska

  The First Things First Alaska Foundation wrote in May 2020 that "the Alaska Roadless Rule hinders Southeast Alaska's economic recovery.

• Angoon Woman Walks Her Way to a Healthier Life

  Juneau, Alaska (KINY) - Angoon’s Betty Samato likes to walk. A lot. She has traveled on foot more than 7,000 miles in just over a year and much more since the coronavirus pandemic first began spreading through her home community.

• Frawley Finish Anchors Crimson Bears Relay Title

  Anchorage, Alaska (KINY) - In the final leg of his final race as a high school senior, in the last event of the 2021 State Swimming & Diving Championship at Bartlett High School, Juneau-Douglas Yadaa.at Kalé senior Tytan Frawley touched the pool wall to clinch the state championship for the Crimson Bears boys' 400 yard relay. A few lanes down, Kodiak’s Jackson Krug also stretched to the finish with the identical time.

• Seward’s Jacoby, Thunder Mountain’s Foy Top Swimmers at State Meet

  Anchorage, Alaska (KINY) - Seward senior Lydia Jacoby and Thunder Mountain High School sophomore Patrick Foy were named the outstanding female and male swimmers at Saturday’s 2021 State Swimming & Diving Championship at Bartlett High School.