Acidification

The Ocean Is Running Out of Breath, Scientists Warn Widespread and sometimes drastic marine oxygen declines are stressing sensitive species—a trend that will continue with climate change

By Laura Poppick on February 25, 2019

Escaping predators, digestion and other animal activities—including those of humans—require oxygen. But that essential ingredient is no longer so easy for marine life to obtain, several new studies reveal.

In the past decade ocean oxygen levels have taken a dive—an alarming trend that is linked to climate change, says Andreas Oschlies, an oceanographer at the Helmholtz Center for Ocean Research Kiel in Germany, whose team tracks ocean oxygen levels worldwide. “We were surprised by the intensity of the changes we saw, how rapidly oxygen is going down in the ocean and how large the effects on marine ecosystems are,” he says.

It is no surprise to scientists that warming oceans are losing oxygen, but the scale of the dip calls for urgent attention, Oschlies says. Oxygen levels in some tropical regions have dropped by a startling 40 percent in the last 50 years, some recent studies reveal. Levels have dropped more subtly elsewhere, with an average loss of 2 percent globally.

See Full Article at Source: https://www.scientificamerican.com/article/the-ocean-is-running-out-of-breath-scientists-warn/

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Ocean acidification to hit levels not seen in 14 million years

New research led by Cardiff University has shown that under a 'business-as-usual' scenario of carbon dioxide (CO2) emissions, ocean acidification is likely to hit unprecedented levels.

Ocean acidification occurs when CO2 from the atmosphere is absorbed by seawater, resulting in more acidic water with a lower pH.

Around a third of the CO2 released by burning coal, oil and gas gets dissolved into the oceans. Since the beginning of the industrial era, the ocean has absorbed around 525 billion tons of CO2, equivalent to around 22 million tons per day.

The rapid influx of CO2 in to the oceans is severely threatening marine life, with the shells of some animals already dissolving in the more acidic seawater.

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In their new study, published in the journal Earth and Planetary Science Letters, the researchers set out to reconstruct levels of ocean acidity and atmospheric CO2 levels over the past 22 million years.



See full article at: https://phys.org/news/2018-07-ocean-acidification-million-years.html#jCp

Ocean Acidification

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Carbon dioxide in the water puts shelled animals at risk.

 

For tens of millions of years, Earth's oceans have maintained a relatively stable acidity level. It's within this steady environment that the rich and varied web of life in today's seas has arisen and flourished. But research shows that this ancient balance is being undone by a recent and rapid drop in surface pH that could have devastating global consequences.

Source:  https://www.nationalgeographic.com/environment/oceans/critical-issues-ocean-acidification/