what is ocean acidification?
Ocean acidification is the chemical change when CO2 from the atmosphere dissolves into seawater, lowering pH and reducing carbonate ions that many marine organisms need to build shells and skeletons.
Video Summary
Climate change: what is ocean acidification?
Main takeaways
01
ocean acidification is caused by atmospheric CO2 dissolving into seawater and lowering pH; the ocean is still alkaline but becoming more acidic.
02
since the Industrial Revolution average ocean pH fell from ~8.2 to ~8.05 — a ~40% increase in acidity — with larger changes projected this century.
03
acidification weakens calcium carbonate shells and coral skeletons, causing oyster hatchery failures, coral porosis and dissolving sea-butterfly shells.
04
coastal communities and global seafood supplies are at risk as shellfish and food-web changes reduce harvests and ecosystem services.
05
solutions center on cutting CO2 emissions; supplementary actions include seagrass/kelp farming and ocean carbon-capture technologies, but scaling is challenging.
Key moments
Questions answered
how much has the ocean's pH changed since the Industrial Revolution?
Average ocean pH has fallen from about 8.2 to roughly 8.05 — a seemingly small shift that represents about a 40% increase in acidity, with larger changes projected by century's end.
why were oyster hatcheries collapsing in washington state?
Changing ocean chemistry reduced the availability of carbonate ions, preventing baby oysters from forming shells and causing mass mortality at hatcheries.
what is coral porosis and why does it matter?
Coral porosis is the increased dissolution and weakening of coral skeletons due to acidified waters; it makes reefs crumble, destroying habitats that support diverse marine life.
can ocean acidification be reversed?
The primary way to stop acidification is to reduce CO2 emissions. Complementary measures — like scaling seagrass/kelp farming or deploying ocean carbon-capture tech — can help locally but face major scaling challenges.
how does acidification affect people?
It threatens fisheries and shellfish industries, undermines food security for communities reliant on seafood, and damages livelihoods and cultural practices tied to marine resources.
The Threat of Ocean Acidification 00:00
"It's threatening marine life. These deep-sea coral reefs are like a block of towers; we're removing the bricks from the bottom of these ecosystems."
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Ocean acidification is becoming a critical threat to marine ecosystems, akin to climate change, and is described as climate change's "evil twin." The increase of carbon dioxide in ocean water is gradually damaging the ocean and jeopardizing human livelihoods reliant on marine resources.
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There is a pressing urgency to address ocean acidification and its consequences, as the point of avoiding the worst outcomes may have already passed.
The Importance of Coral Exploration 00:44
"I chose to give my water samples to the Natural History Museum because it was their article on ocean acidification that inspired me."
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Vanessa O'Brien, an explorer, aimed to be the first woman to reach both the deepest part of the ocean and the highest point on Earth. As part of her mission, she collected water samples from the Challenger Deep to contribute to scientific research on ocean acidification.
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In 2020, a study by scientists at London's Natural History Museum revealed alarming increases in ocean acidification since the Industrial Revolution, affecting marine life and particularly shelled creatures.
The Impact on Marine Organisms 02:50
"The ocean's pH level has decreased from 8.2 to around 8.05, equating to an increase in acidity of around 40 percent."
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Ocean acidification is quantified by a decrease in pH levels, where the ocean's alkalinity has diminished, leading to significant biological impacts. A drop from 8.2 to 8.05 may appear small, but it represents a serious increase in acidity, expected to rise further by the end of the century.
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The changes in ocean chemistry primarily stem from increased carbon dioxide emissions associated with fossil fuel combustion, which hinders marine organisms, especially those that rely on calcium for shell formation.
The Link Between Acidification and Coral Health 05:55
"Ocean acidification is the prime suspect in the destruction of deep cold-water coral, which is essential to the marine ecosystem."
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Dr. Sebastian Henninger emphasizes the detrimental role of ocean acidification in coral health, particularly in cold-water coral ecosystems that support vast biodiversity. If these corals decline, it could cause widespread disruptions in marine food chains.
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His research indicates a condition called "coral porosis," where the structural integrity of corals declines due to acidification, leading to potential ecosystem collapse.
Threats to Human Livelihoods 08:41
"My community is very dependent on the ocean not only for economic benefits but for subsistence; everybody in our community subsists in one way or another."
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The impacts of ocean acidification extend beyond marine life, threatening the livelihoods of communities that depend on fishing and marine resources. Raven Cunningham, a commercial fisherman from Alaska, illustrates how changing ocean conditions have diminished the quantity of shellfish harvested.
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Ocean acidification is disrupting food sources for species like salmon, which are critical to local economies and cultural practices, thereby amplifying the challenges faced by indigenous communities reliant on these resources.
Ocean Acidification and Its Impact on Marine Life 11:36
"The shells of this vital species are dissolving in waters all over the world."
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Sea butterflies, notable for their beautiful appearance and flying wing-like movements, are currently facing a critical threat as their shells dissolve due to increasing ocean acidification.
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This phenomenon poses significant risks not only to marine biodiversity but also to the global food supply chain, as approximately 40% of the world's population relies on seafood as an essential source of protein.
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Signs of ocean acidification are evident globally, with various marine species exhibiting cracking shells and dissolution, indicating that this environmental concern is a reality that necessitates urgent action.
Solutions to Tackle Ocean Acidification 12:27
"The most effective answer is one you've probably heard many times before: reduce our carbon dioxide emissions."
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Addressing ocean acidification requires a focus on reducing carbon dioxide emissions, with a significant emphasis on decreasing fossil fuel consumption as the primary strategy.
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While reducing atmospheric carbon is essential, additional methods are available to manage the carbon already dissolved in the oceans. For instance, growing underwater plants such as seagrass and kelp can effectively absorb carbon, capturing it up to 35 times faster than tropical rainforests.
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However, to make a substantial impact on current carbon dioxide levels, extensive seaweed farming would be required.
Innovative Approaches in Carbon Capture 13:21
"Hindel's technology is novel, capturing it from the sea, which contains more carbon dioxide by volume than the atmosphere does."
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Companies like Hindel are exploring innovative technologies for carbon capture, specifically from ocean waters, where carbon dioxide is significantly more concentrated than in the atmosphere.
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Hindel aims to restore ocean pH levels to those recorded in the 1870s, striving to revive marine life and combat acidification effectively.
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The proposed solution entails systems designed to fit within standard shipping containers, but scaling this technology to capture global CO2 emissions remains a substantial challenge, as it would require an immense number of units to be effective.
The Interconnectedness of Carbon Emissions and Ocean Acidification 14:50
"You can't get away from the fact that, like climate change, ocean acidification is the result of carbon emissions."
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Despite various measures to mitigate ocean acidification, the overarching challenge of carbon emissions remains unaddressed, highlighting the limitation of mitigating oceanic carbon without concurrently reducing atmospheric levels.
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The current trajectory of carbon emissions necessitates urgent and sustained efforts to confront what many consider one of the most pressing issues of our time.
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The metaphor of a "car crash" serves as a stark reminder that the time to avert catastrophic outcomes has passed, and the focus must now shift to ensuring that we can recover from the impending crises associated with climate change and ocean acidification.