"Long before it's in the papers"
January 28, 2015


Oceans acidifying much faster than was thought: study

Nov. 26, 2008
Courtesy University of Chicago
and World Science staff

The oceans are becoming more acidic, and much faster than pre­vi­ously thought, sci­en­tists say. The pro­cess, a pos­sible threat to some ocean life, seems to be linked with ris­ing lev­els of at­mos­pher­ic gas­es that are blamed for glob­al warm­ing, ac­cord­ing to the re­search­ers.

O­cean­side rocks cov­ered with mus­sels are one hab­i­tat that may be threat­ened by in­creas­ing ocean acid­i­ty, re­search­ers say. (Cred­it: J.T. Woot­ton, U. Chi­cago).

Univers­ity of Chi­ca­go scientists de­tailed the new find­ings in a pa­per pub­lished on­line by the re­search jour­nal Pro­ceed­ings of the Na­tional Acad­e­my of Sci­ences Nov. 24.  The study is based on 24,519 mea­sure­ments of ocean ac­id­ity span­ning eight years.

Dur­ing that time, “the ac­id­ity in­creased more than 10 times faster” than cli­mate change mod­els and oth­er stud­ies had pre­dicted, said the uni­ver­s­ity’s J. Tim­o­thy Woot­ton, lead au­thor of the stu­dy. “This in­crease will have a se­vere im­pact on ma­rine food webs.”

Woot­ton and col­leagues said the pro­cess seems to be oc­cur­ing in step with in­creas­ing lev­els of car­bon di­ox­ide in the at­mos­phere. Car­bon di­ox­ide is a key “green­house gas,” a com­pound that re­search­ers say acts as a large-scale blan­ket in the at­mos­phere, trap­ping heat on Earth and thus driv­ing glob­al warm­ing.

When the car­bon di­ox­ide dis­solves in wa­ter it forms car­bonic ac­id. Ab­nor­mally ac­idic wa­ter harms cer­tain sea an­i­mals, the au­thors said. “Many sea crea­tures have shells or skele­tons made of cal­ci­um car­bonate, which the ac­id can dis­solve,” said the uni­ver­s­ity’s Cath­er­ine Pfis­ter, a co-au­thor of the stu­dy. 

They added that the acidity could re­duce the ocean’s abil­ity to soak up more car­bon di­ox­ide, a pro­cess which some have hoped would miti­gate cli­mate change.

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The oceans’ acidity is growing faster than previously thought, scientists say—a process thought to be linked with rising levels of atmospheric gases that are blamed for global warming. University of Chicago researchers detailed the new findings in a paper published online by the research journal Proceedings of the National Academy of Sciences Nov. 24. During the course of the study, “the acidity increased more than 10 times faster” than climate change models and other studies had predicted, said the university’s J. Timothy Wootton, lead author of the study. “This increase will have a severe impact on marine food webs and suggests that ocean acidification may be a more urgent issue than previously thought, at least in some areas of the ocean.” Wootton and colleagues said the process seems to be occuring in step with increasing levels of carbon dioxide in the atmosphere. Carbon dioxide is a key “greenhouse gas,” a compound that researchers say acts as a large-scale blanket in the atmosphere and that traps heat on Earth, driving global warming. When atmospheric carbon dioxide dissolves in water it forms carbonic acid. Abnormally acidic water harms certain sea animals and could reduce the ocean’s ability to soak up carbon dioxide, the authors said. The study is based on 24,519 measurements of ocean acidity spanning eight years. “Many sea creatures have shells or skeletons made of calcium carbonate, which the acid can dissolve,” said the university’s Catherine Pfister, a co-author of the study.