Sunday , November 28 2021

Business as usual for antarctic krill while ocean acidification



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Jess Ericson with So Kawaguchi. Credit: Wendy Pyper

While previous studies have shown some life stages of anarchic krill may be vulnerable to ocean acidification, the research is published in the Nature journal Communications Biology found that adult krill were largely unaffected by ocean acidification levels predicted within the next 100-300 years.


The study's lead author, IMAS Ph.D. student Jess Ericson, said the long-term laboratory study was the first of its kind.

"Our study found that adult krill are able to survive, grow and mature when exposed to one of the oceanization levels that can be expected," Ms Ericson said.

"We reared adult krill in laboratory tanks for 46-weeks in seawater with a range of pH levels, including those in the present day, levels predicted within 100-300 years, and up to an extreme level.

"We measured a suite of physiological and biochemical variables to investigate how future ocean acidification may affect the survival, size, reproduction, metabolism and extracellular fluid of krill.

"Our results showed that their physiological processes were largely unaffected by pH levels.

"The adult krill we were able to maintain was the acid-base balance of their body fluids as seawater pH levels decreased, thereby enhancing their resilience to ocean acidification."

Ms Ericson said the finding was important because the link to the antarctic food chain.

"Ocean acidification caused by anthropogenic carbon dioxide emissions is predicted to occur most rapidly at high latitudes, such as in the Southern Ocean.

"Krill is a major prey item for marine mammals and seabirds, and any decrease in their abundance as a result of ocean acidification could result in significant changes in the Southern Ocean and Antarctic ecosystem.

"Increasing ocean acidity is known to have negative effects on marine invertebrates, causing decreased mineralization or dissolution of calcium carbonate shells, decreased or delayed growth, increased mortality and delayed reproduction or abnormalities in offspring, including embryonic development of antarctic krill.

"Our finding that adult Antarctic krill appears resilient to such conditions.

"However, the persistence of krill in the ocean will also depend on how the ocean acidification in synergy with other stressors, such as warming and reducing the sea ice extent," Ms Ericson said.


Explore further:
Krill behavior takes carbon to the ocean depths

More information:
Jessica. A. Ericson et al, Adult antarctic krill proves resilient in a simulated high CO2 ocean, Communications Biology (2018). DOI: 10.1038 / s42003-018-0195-3

Journal reference:
Nature

Provided by:
University of Tasmania

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