Ocean acidification threatens marine life by altering seawater chemistry and skeletal formation

Nature · Published 21 October 2026 Swipe more like this →

In short: Researchers reviewing global ocean data found that the uptake of human-made carbon dioxide is fundamentally changing seawater chemistry. This shift, known as ocean acidification, makes it increasingly difficult for many marine species—particularly molluscs and tiny shelled organisms—to build and maintain their calcium carbonate skeletons.

The study highlights how rising CO2 levels cause the saturation horizon for calcium carbonate to shoal, especially in high latitudes and hypoxic zones. Beyond skeletal issues, increased acidity can disrupt the internal physiology of marine life by causing acid-base imbalances and reducing oxygen transport.

This review synthesizes existing data and new observations to identify vulnerable ecosystems. However, because few studies have tested these impacts at the specific CO2 levels expected in the future, it remains difficult to predict how these changes will ultimately shift entire foodweb dynamics.

Why it matters: Ocean acidification creates a physiological hurdle for marine life, potentially reshaping entire underwater foodwebs as chemistry shifts.

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