Saturday , May 15 2021

Firms as usual for Antarctica krill despite increased acidification

A new Institute for Marine and Antarctic Studies (IMAS) has shown that Antarctica Bar is resistant to increasing acidification of the ocean, as it absorbs more CO2 from the atmosphere due to anthropogenic carbon dioxide emissions.

Krill is one of the most extensive organisms on earth and a critical part of the marine ocean's ecosystem in the South Sea.

While previous studies indicate that some of the Antarctica's life stages may be vulnerable to sea drift, the research published in the Nature Journal Communication Biology showed that adult barbecue was largely unaffected by the ocean's acidity levels predicted within the next 100-300 years.

The study's leading author, IMAS doctoral student Jess Ericson, in the picture, said the long-term laboratory survey was the first of its kind.

"Our study showed that adult kids can survive, grow and mature when exposed to up to one year to levels of acidity that can be expected in this century," said Ericson.

"We bred adult barrels in laboratory tanks for 46 weeks in seawater with a range of pH levels, including those currently, levels foreseen within 100-300 years and up to an extreme level.

"We measure a set of physiological and biochemical variables to investigate how future ocean acidity can affect survival, size, lipid stores, reproduction, metabolism and extracellular fluid of krill.

"Our results showed that their physiological processes were largely unaffected by pH levels that they are expected to counteract in the coming century.

"The adult krill we monitored was able to actively maintain the acid base in their body fluids when the sea level's pH level decreased, thereby increasing their resistance to sea acidification."

Ericson said it was important to find it because Krill is a key link in the Antarctic food chain.

"Ocean pollution caused by anthropogenic carbon dioxide emissions is estimated to occur most rapidly at high latitudes, for example in the southern ocean.

"Krill is an important substitute for marine mammals and seabirds, and any reduction of their abundance as a result of marine acidification can lead to significant changes in the Southern Ocean and Antarctic ecosystem.

"Increasing sea acidity is known to have adverse effects on a number of marine invertebrates, resulting in reduced mineralization or dissolution of calcium carbonate scale, reduced or delayed growth, increased mortality and delayed reproduction or abnormalities in offspring, including embryonic development of Antarctica.

"Our finding that adult Antarctic bar seems resilient to such conditions is therefore an interesting and significant result.

"However, Krill's detention in a changing ocean will also depend on how they respond to acidification in synergy with other stressors, such as ocean heating and ocean-level reductions," says Ericson.

The study also included researchers from ACE CRC, CSIRO Oceans & Atmosphere, the Australian Antarctic Department and Aker Biomarine in Norway.

Photo credits: Wendy Pyper.

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