An international team of researchers has set new alarms about chemical changes in the western regions of the Arctic Ocean after finding acidity levels rise three to four times faster than seawater elsewhere. I was.

The team, which includes Wei-Jun Cai, a marine chemistry expert at the University of Delaware, also identified a strong correlation between the accelerated rate of ice melt in the region and the rate of ocean acidification. Coral reefs and other marine life, biological processes throughout the Earth’s ecosystems.

New study published Thursday, September 30 chemistrythe first analysis of Arctic acidification containing more than 20 years of data spanning the period 1994-2020.

Scientists predict that by 2050, sooner than that, the region’s Arctic sea ice will be unable to survive the increasingly hot summer season. As a result of sea ice retreating each summer, ocean chemicals become more acidic and there is no permanent ice cover to slow or moderate the advance.

This creates life-threatening problems for the highly diverse populations of sea creatures, plants, and other organisms that depend on healthy oceans for survival. It lives in a crusty shell made of calcium. Polar bears depend on healthy fish populations, fish and seabirds depend on plankton and plants, and seafood is an important component of many human diets.

As such, the acidification of these distant oceans poses a major problem for many of the planet’s inhabitants.

First, a quick review of pH levels, which indicate how acidic or alkaline a particular liquid is. Liquids, including water, can be characterized by pH levels ranging from 0 to 14, with pure water being considered neutral at pH 7. All levels below 7 are acidic and all levels above 7 are basic or alkaline. Each complete step represents a 10-fold difference in hydrogen ion concentration. Examples on the acidic side include battery acid, which checks in at pH 0, stomach acid (1), black coffee (5), and milk (6.5). Leaning toward basic are blood (7.4), baking soda (9.5), ammonia (11), and drain cleaner (14). Seawater is usually alkaline, with a pH value of about 8.1.

Kai is a Mary AS Lighthype professor in the Department of Marine Science and Policy at UD’s College of Earth, Oceans and the Environment, has published significant research on chemical changes in the Earth’s oceans, and is sailing from Nova Scotia to Florida this month. Has completed. As 27 chief scientists on a research ship. This research includes his four research areas: East Coast, Gulf of Mexico, Pacific Coast, and Alaska/Arctic regions.

new research in chemistry UD postdoctoral researcher Zhangxian Ouyang, who participated in recent expeditions to collect data in the Arctic Chukchi Sea and Canadian Basin.

The original author of this publication was Di Qi, working with Chinese research institutes in Xiamen and Qingdao. The publication also collaborates with scientists from Seattle, Sweden, Russia and six other Chinese research institutes.

“You can’t go it alone,” said Kai. We are also collaborating with Japanese scientists as -19 has made the Arctic Ocean more difficult to access in the last three years 19. And European scientists are always on board.”

Tsai said both he and Qi were baffled when they first reviewed the Arctic data together at a meeting in Shanghai. The acidity of the water was increasing 3-4 times faster in him than in seawater elsewhere.

It was really nice. But why did it happen?

Tsai quickly identified the prime suspect. That is, the melting of sea ice increased during the Arctic summer.

Historically, Arctic sea ice has melted in the shallow areas around it during the summer season. That began to change in the 1980s, but has cyclically increased and decreased, Cai said. Over the past 15 years, ice melt has accelerated and advanced into deeper basins in the north.

For a while, scientists thought melting ice would provide a promising ‘carbon sink’. There, atmospheric carbon dioxide is sucked into the cold, carbon-hungry water that was hidden beneath the ice. That colder water holds more carbon dioxide than warmer water, which may help offset the effects of increased carbon dioxide elsewhere in the atmosphere.

When Kai first surveyed the Arctic Ocean in 2008, he saw ice melting all the way across the Chukchi Sea in the northwestern corner of the Arctic Ocean to the Canada Basin. This is well beyond the normal range. He and his collaborators found that the fresh meltwater did not mix with the deeper waters, diluting the carbon dioxide. Instead, surface water absorbed carbon dioxide and stopped collecting it after it reached roughly the same level as in the atmosphere.They reported this result in their paper chemistry in 2010.

They knew it would also change the pH level of the Arctic Ocean, lowering the seawater’s alkalinity levels and its ability to resist acidification. And how long? It took another decade to collect enough data to draw good conclusions about long-term acidification trends.

Such a long-term perspective is possible for the first time when analyzing data collected from 1994 to 2020. Cai, Qi, and their collaborators found a strong correlation between anomalous increases in acidification and increased ice melt rates.

They point to the melting of sea ice as an important mechanism explaining this rapid pH drop. Because it changes the physics and chemistry of surface waters in three main ways.

• The water under the sea ice, which had been deficient in carbon dioxide, was exposed to atmospheric carbon dioxide and became free to absorb it.
• Seawater mixed with melt water is light and does not mix easily with deep water. In other words, carbon dioxide taken in from the atmosphere concentrates on the surface of the earth.
• Melt water dilutes the carbonate ion concentration in seawater, weakening its ability to neutralize carbon dioxide to bicarbonate and rapidly lowering ocean pH.

Tsai said more research is needed to further refine the above mechanisms and predict future changes more accurately, but data so far show widespread spillover effects of climate change. I’m here.

“When all the multi-year ice is replaced by first-year ice, alkalinity and buffering capacity decrease, and acidification continues,” he said. “We believe that by 2050 all ice will be gone in the summer. Some papers predict that by 2030. If so, summer acidification will be really, really strong.”

No one knows exactly how that will affect the creatures, plants, and other organisms that depend on healthy seawater.

“How does this affect the biology there?” Tsai asked. “That’s why this is important.”