Pivotal octopus, ocean acidity study attracts international media

RIVERSIDE, Calif. – The collaborative work of scientists at La Sierra University and Walla Walla University has widened the scientific window into the potential effects of climate change and garnered international coverage of their findings.

At times using innovative equipment they engineered themselves, marine biologists Lloyd Trueblood, an associate biology professor at La Sierra University and Kirt Onthank, associate biology professor at Walla Walla University analyzed the East Pacific ruby octopus or Octopus rubescens in one and five-week studies at WWU’s collaborative Rosario Beach Marine Laboratory. It was the first analysis of octopus that compared short and long-term effects of sea water acidified through increased carbon dioxide levels. Previous short-term studies focused on squid and cuttlefish. The journal Physiological and Biochemical Zoology from the University of Chicago Press published their research and issued a press release in January announcing findings that showed the octopuses had adapted to increased sea water acidity by returning to and maintaining normal metabolic rates, or energy usage levels after an initial reaction in which they used more energy following a first exposure.

Ocean acidification occurs when carbon dioxide or CO2, which results from fossil fuels spewing into the air, dissolves into the ocean, dropping pH levels and increasing seawater acidity. The ocean absorbs about 30% of the CO2 released into the atmosphere, according to the National Oceanic and Atmospheric Administration, resulting in harm to marine life.

Trueblood and Onthank are building on the results from their five-week study and exploring methods the octopus may be using to overcome the stress of acidic oceans, such as editing RNA, changing gill transport proteins, and modifying blood oxygen-carrying proteins. Students in both of their labs are assisting with the process.

Collaboration is key

They both earned master’s degrees in biology from Walla Walla University, Trueblood in 2002, six years ahead of Onthank who was undergraduate at the time. The two never crossed paths, however, until Trueblood was three or four years in his doctoral studies at the University of Rhode Island, around 2006. “I was having a hard time doing some data management, and I called my professor at Walla Walla for ideas and he’s like, ‘I don’t know how to do that but there’s this kid here [who] probably does. And so I got on the horn with Kirt and he helped me develop this pivot table thing to do some data management stuff,” said Trueblood.

Onthank earned a doctorate in 2013 from Washington State University and Trueblood received his from the University of Rhode Island in 2010. Onthank had worked with octopuses during undergraduate and graduate training at Walla Walla and currently studies marine invertebrate physiology, particularly cephalopods such as octopus and squid in the Onthank Physiology Lab. He viewed the study of the impacts of ocean acidification “as kind of the big pressing question about what’s going to happen to octopuses going forward,” he said.

Similarly, Trueblood had worked with a research group during his doctoral program that had pursued “ground floor” studies on the physiological effects of ocean acidification on squid, a problematic effort due to the squid’s inability to handle being inside of a tank for long periods. “And so we were both kind of starting out our labs and Kirt at one point was like, ‘hey man, I’m interested in doing this acidification stuff on octopus, what are your thoughts,’ and we just kind of started talking from there and comparing notes and ideas,” Trueblood said. He was intrigued by the opportunity of studying octopus in part because of the creature’s amenability to life in a lab tank.

The scientists initiated the five-week study of Octopus rubescens in the summer of 2014. They harvested the ruby octopuses from Washington’s Puget Sound where a naturally low pH level results in continuously high water acidity that is on par with predictions for ocean acidic levels this century. “We basically have a future test ground,” said Trueblood.

Puget Sound, a shallow inlet of the Pacific Ocean along the northwestern coast of Washington State, incurs an upwelling of deeper ocean water washing in at its mouth that is higher in acidity than typical ocean water. Additionally, through a phenomenon called the biological curve, carbon dioxide is deposited into deeper water when phytoplankton, which normally live in light-infused water near the surface, die and transport CO2 to the bottom of the deep ocean where the phytoplankton are consumed by bacteria and other things which likewise respire out CO2. Because of the sound’s comparative shallowness and lack of direct exposure to the open sea, the deep water and its CO2 deposits mixes with the surface water leading to an accumulation and mixing of carbon dioxide deposits throughout the water levels of Puget Sound.

Darla Martin Tucker, La Sierra University, 11 March 2021. Full article.

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