Ocean acidification is the ongoing decrease in ocean pH caused primarily by uptake of anthropogenic CO₂ from the atmosphere, leading to shifts in the seawater carbonate system. Dissolved CO₂ forms carbonic acid, which dissociates to release hydrogen ions and convert carbonate ions to bicarbonate, reducing carbonate saturation states critical for calcifying organisms (e.g., corals, coccolithophores, mollusks). Research focuses on quantifying pH and aragonite/calcite saturation changes, organismal and ecosystem responses, biogeochemical feedbacks, and interactions with other stressors such as warming and deoxygenation, using observations, laboratory experiments, mesocosms, and Earth system models.
When most people hear the phrase "ocean acidification," they think of coral reefs, shellfish or declining fisheries. Those concerns are real. But while working on our recent research, I found myself asking a different question: ...
A new Stanford-led study offers the clearest picture yet of how some ocean life survived our planet's biggest mass extinction while most animals did not. About 252 million years ago, 96% of marine species and 70% of land ...
Evolution
Jul 10, 2026
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An ongoing research project exploring the effects of rising levels of oceanic CO2 on squid neurology reveals that exposure to future levels of ocean acidification could shrink their brain volume by around 50%. This severe ...
Plants & Animals
Jul 8, 2026
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Microscopic plankton are among the most important organisms on Earth. Phytoplankton produce around half of the oxygen we breathe, while plankton as a whole underpin marine food webs, support fisheries, help regulate carbon ...
Environment
Jun 29, 2026
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The eastern tropical Pacific Ocean is known for its large low-oxygen zones that are increasing in size, putting marine life at risk. New research shows that 15 million years ago, the opposite was true.
Earth Sciences
Jun 26, 2026
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Most people have experienced a heat wave on land. But heat waves can strike in the ocean too. And as the planet continues to warm, marine heat waves are growing longer and deadlier, hurting the seafood supply that billions ...
Earth Sciences
Jun 12, 2026
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Scientists at Scripps Institution of Oceanography at the University of California San Diego reported today that carbon dioxide levels at Mauna Loa Observatory reached 432.00 parts per million (ppm) in May, continuing a long ...
Environment
Jun 11, 2026
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One of the most devastating extinctions in Earth's history is best known for what didn't die—dinosaurs. But the end-Triassic extinction 201 million years ago wiped out roughly 60% of Earth's species, and scientists are still ...
Earth Sciences
Jun 1, 2026
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The ocean is an important carbon sink that absorbs 20–30% of the total anthropogenic CO2 emissions in the industrial era (1.0–3.0 Pg annually, 1 Pg = 1015 g). Tropical cyclones are among the most devastating weather systems ...
Earth Sciences
May 25, 2026
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A new study from Adelaide University has found that when ocean acidification makes reef habitat less complex, the fish living there gather in smaller shoals that offer less social protection.
Plants & Animals
May 22, 2026
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