Saving Seafood

Researchers Say the Oceans Have Passed a Milestone for Acidification

January 5, 2026 — The past 12 months have been worrying for researchers who study the chemistry of the ocean. More and more evidence has been published showing that human activities are fundamentally altering this chemistry in an acidic direction.

At the end of 2025, it seems clear ocean acidification is pushing the largest habitat on Earth into a risky zone.

Ocean acidification is part of the global carbon cycle. When carbon dioxide dissolves in water, it forms carbonic acid. This acid releases hydrogen ions, which lower the seawater’s pH balance.

pH balance

This sliding scale of 14 points indicates the acid/alkaline balance of a solution. Position 1 indicates the highest acidity, 14 the highest alkalinity. It stands for “potential of hydrogen”, because the scale is determined by the concentration of hydrogen ions.

Carbon dioxide emitted by human activities may be largely released into the atmosphere, but it does not all stay there. Huge amounts are absorbed by the ocean. A study published in 2023 determined that the ocean absorbed 25% of anthropogenic CO2 emitted from the early 1960s to the late 2010s. This has so far saved humanity from greater global warming.

Because of the rise in atmospheric CO2 concentrations over the past century, more CO2 has been taken up by the ocean, causing it to acidify.

Read the full article at the Maritime Executive

Scientists find coastal seas acidifying shockingly fast

December 1, 2025 — New research from the University of St Andrews reports that some coastal regions are on track to become far more acidic than scientists once believed. As additional atmospheric CO2 enters the air, it dissolves into the ocean more quickly than anticipated, driving a rapid drop in pH that threatens coastal industries and livelihoods around the world.

Because atmospheric CO2 and ocean pH (acidity) rise and fall together, any increase in CO2 above the ocean is soon reflected in the water below. This steady absorption of carbon makes seawater progressively more acidic over time.

Upwelling Systems Intensify Ocean Acidification

In a study published on November 13th in Nature Communications, the research team used the California Current as a case study and found that upwelling regions significantly intensify ocean acidification rather than simply reflecting atmospheric trends.

Upwelling occurs when deeper ocean layers, which are already nutrient rich and naturally acidic, move upward toward the shore. Organic material from surface waters sinks and is broken down by microbes in the deep ocean, a process that releases CO2 and increases acidity. When these deep waters rise again, they deliver this accumulated acidity back to the surface, where the water interacts with atmospheric CO2 and becomes even more acidic.

Read the full article at Science Daily

Coastal ocean acidification advancing faster than expected, threatening local economies

November 14, 2025 — New research from the University of St Andrews has found that some coastal areas will become much more acidic than previously anticipated. With added atmospheric CO2, these areas are acidifying more quickly than thought, posing an existential threat to coastal economies around the world.

Because atmospheric CO2 and ocean pH (acidity) are tightly coupled, the more CO2 that is released into the atmosphere, the more is absorbed by seawater, making the ocean progressively more acidic.

However, in a paper published in Nature Communications, researchers, using the California Current as an example, show that oceanic upwelling systems actually amplify .

Read the full article at phys.org

From Fishermen To Rugby Players, Climate Change Has Become A Fact Of Life In Fiji

February 17, 2022 — When Shahadat Ali was learning how to fish, he was taught to put the smaller fish back into the ocean. But the quality, size and amount of fish have decreased so dramatically that he now has to keep every fish that swims into his net.

“Times are hard — it’s a struggle,” said Ali, who lives on the outskirts of Nasinu, the most populous town on the island of Viti Levu in Fiji.

Ali’s 72-year-old uncle, Iqbal Shah, has been fishing since he was a teenager and has seen the ocean he loves change drastically over his lifetime.

“In one week we used to catch 300 to 400 kilograms, sometimes 500 kilograms, but now if you fish one week, you can’t hardly get about 100 kilograms (220 pounds),” Shah said. “It is very hard.”

Read the full story at the Honolulu Civil Beat

 

The impact of ocean acidification

February 20, 2019 — For more than a century, the world’s oceans have been becoming steadily more acidic as they soak up ever-increasing amounts of carbon dioxide from the atmosphere, and the impacts can be fatal for invertebrates such as shellfish, plankton, and corals that rely on dissolved minerals to build their shells and exoskeletons.

For at least some fish, though, the story may be more complicated.

Using precise CT scans of skate skeletons, Valentina Di Santo, a postdoctoral fellow in the lab of Evolutionary Biology Professor George Lauder, was able to show that, while ocean acidification has had led to a drop in the mineralization of some parts of the skeletons, it has had the opposite effect in other areas. The first-of-its-kind study suggests that continued ocean warming and acidification could impact everything from how fish move to how they eat. The findings are described in a Jan. 9 paper published in the Proceedings of the Royal Society B.

“This result was very surprising,” Di Santo said. “Until now, most research had been focused on the mineralization of the exoskeletons of invertebrates, because we know they experience very dramatic impacts from acidification, but nobody had looked at what happens to vertebrates.”

Read the full story at The Harvard Gazette

More acidic seawater now dissolving bit of Florida Keys reef

May 4, 2016 — Seawater — increasingly acidic due to global warming — is eating away the limestone framework for the coral reef of the upper Florida Keys, according to a new study. It’s something that scientists had expected, but not so soon.

This is one of the first times scientists have documented long-term effects of ocean acidification on the foundation of the reefs, said study author Chris Langdon, a biological oceanographer at the University of Miami.

“This is what I would call a leading indicator; it’s telling us about something happening early on before it’s a crisis,” Langdon said. “By the time you observe the corals actually crumbling, disappearing, things have pretty much gone to hell by that point.”

The northern part of the Florida Keys reef has lost about 12 pounds per square yard (6.5 kilograms per square meter) of limestone over the past six years, according to the study published in the journal Global Biogeochemical Cycles. Over the length of the reef, that’s more than 6 million tons. The water eats away at the nooks and crannies of the limestone foundation, making them more porous and weaker, Langdon said.

Read the full story at the New Jersey Herald

Marine Invasive Species Benefiting from Rising Carbon Dioxide Levels

November 6, 2015 — Ocean acidification may well be helping invasive species of algae, jellyfish, crabs and shellfish to move to new areas of the planet with damaging consequences, according to the findings of a new report.

Slimy, jelly-like creatures are far more tolerant of rising carbon dioxide levels than those with hard structures like corals, since exposed shells and skeletons simply dissolve away as CO2 levels rise.

The study, conducted by marine scientists at Plymouth University, has found that a number of notorious ‘nuisance’ species – such as Japanese kelp (Undaria pinnatifida) and stinging jellyfish (Pelagia noctiluca) are resilient to rising CO2 levels. Published in Research and Reports in Biodiversity Studies, it notes that in the tropics, coral reefs face a host of interconnected problems (bleaching, corrosion, disease, spreading seaweed, invasive species) that are all caused by rising CO2 levels.

Read the full story from Alaska Native News