Oceans Need Geoengineering, Not The Atmosphere

July 17th, 2019 by 


Geoengineering is the study, and potential practice of, intentional large-scale changes to the Earth’s systems. Most ethicists are very cautious about it, but recent news of potential carbon-spikes suggests an area where it may be absolutely necessary: the oceans.

We have solutions for the causes of global warming. Geoengineering as it’s commonly understood is a bandaid on the symptoms of it, in my opinion.

I had this conversation with one of the pre-eminent global geoengineering advocates and engineers, David Keith of Harvard, recently. He saw the potential need long ago, and his first paper on the subject was published in 1992. That makes him one of the pre-eminent authorities on the subject, so please understand that I’m not asserting that I know more than he does. However, my opinion (which he disagreed with) is that if we have to use geoengineering as he envisions it, we’ve probably failed and the results will be worse. I’m sure if we’d had more time and that had been the focus of the discussion as opposed to a sideline, our views would more substantially overlap.

Let’s define geoengineering briefly. The premise Keith and others advance is that we can increase the albedo — reflectivity — of the Earth’s atmosphere slightly to decrease the energy from the Sun that reaches the ground. This in turn reduces the infrared that the ground emits that’s trapped by greenhouse gases. The technology proposed uses sulphur dioxide in the high atmosphere, millions of tons of it a year.

In theory, it’s possible. In practice, the downsides are unknown and we are trying to stabilize a chaotic system by directly controlling it. The odds of unexpected feedback oscillation and other adverse effects are high. Further, ethicists point out the likelihood that using it to mask the impacts of fossil fuel greenhouse gas emissions would lead to both more use of fossil fuels, and to an inevitable failure in the future when we stop the geoengineering effort. Part of my concern is that fossil fuel companies will jump on the geoengineering bandwagon as they have jumped on the carbon capture bandwagon, and prevent the actually necessary actions.

And that’s already happening. The Center for Investigative Reporting published a lengthy assessment of the climate change skeptics close to President Trump, who were backing geoengineering efforts early in 2018. Keith is on record as being unnerved by the potential for this, saying in a 2017 conference:

In some ways the thing we fear the most is a tweet from Trump saying, “Solar geoengineering solves everything! It’s great! We don’t need to bother to cut emissions.”

In our recent conversation, Keith seemed unaware that this was already underway, although President Trump’s tweets have focused more on vicious attacks than global warming in the past year.

Of course, putting 20 million tons of anything into the high atmosphere every year is non-trivial as well. Who will pay for the program? What countries will host the fleets of planes? Where will the chemicals come from?

My preference for thinking related to solar geoengineering is best embodied in the Oxford Principles. (Full disclosure: I have a degree of separation on that as well, as I was speaking recently with the CEO of a firm whose chief scientist, Tim Kruger, collaborated on the Principles)

The Principles basically say that it’s an incredibly complex and risky thing to do, that independent actors have to be prevented from doing it, and that it should only be done under the auspices of a global governance agency, if at all. There’s a case for keeping it in our back pockets and using it after we’ve done the real job of eliminating CO2 emissions, following Mark Z. Jacobson’s prescriptions for 100% renewables by 2050 for every US state, and for 139 countries globally. (More degrees of separation: Jacobson wrote the preface to my upcoming CleanTechnica case study on Keith’s Carbon Engineeringcompany, which as been described hyperbolically and inaccurately as a ‘magic bullet’ by none other than the BBC)

Enter the work of Daniel Rothman, professor of geophysics in the MIT Department of Earth, Atmospheric and Planetary Sciences, and co-director of MIT’s Lorenz Center. He’s one of a small number of climate scientists exploring the potential for truly catastrophic outcomes of our current unintentional geoengineering (global warming due to massive burning of fossil fuels). His most recent publication (peer-reviewed in the Proceedings of the National Academy of Sciences in July 2019), Characteristic disruptions of an excitable carbon cycle, quantifies his observation that mass extinction events historically are tied to spikes in ocean carbon uptake. Whether very slow but steady increases of atmospheric carbon or very abrupt changes in atmospheric carbon can cross the threshold to cause very large changes to ocean chemistry in very brief periods of time, per his models.

I have been thinking recently that some form of geoengineering might be necessary to reduce ocean acidity, and Rothman’s work suggests that the effort might be even more important. Let’s look at the oceanic acidification problem briefly.

Oceanic carbon cycle

 Graphic via Australian-governmental-funded CoastAdapt site.

Oceans are key to the carbon cycle. They’ve absorbed between a third and half of the CO2 that humans have emitted since the beginning of the Industrial Revolution, and the process lags atmospheric CO2 increases. More CO2 will end up in the oceans. The challenge is that CO2 binds with carbonate in the ocean to make carbonic acid, reducing the amount available for shellfish to make their shells. That leads to weaker shells, and species-level threats for key components of the food chain, in addition to the direct impacts of the increased acidity.

That is a very big problem of a very different nature than warming, but with the same root cause. We have to stop emitting CO2 so that oceans don’t acidify even more than absolutely necessary, but even if we stopped now, oceans would be getting more acidic for the next century or two, and that could be fatal to pretty much all of us.

I reached out to Jacobson for his thoughts. There is both good news and bad news in his opinion:

I am not aware of any way to draw down carbon from the oceans that is not energy intensive. Once energy is required to remove anything from anywhere, then the question always becomes, where does that energy come from? If the answer is fossils, the proposal fails. If the answer is renewables, then the proposal also fails because that renewable energy could instead replace fossil fuels at lower cost while also eliminating air pollution and energy security, which removing carbon from the oceans or air does not do, no matter how efficient it is.
Also, I’m not sure I agree with Rothman’s premise. The K-T extinction was not caused by a massive flux of carbon to or from the oceans, it was caused by a comet or asteroid kicking up debris to the stratosphere, spreading horizontally and blocking the sun.

The bad news is that like air carbon capture approaches, money and energy spent on oceanic geoengineering to reduce the impacts would reduce the amount of money and energy necessary to fix the cause of the problem. The good news is that at least one globally respected scholar in this space is skeptical of one aspect of the oceanic carbon challenge.

We obviously have to stop emitting CO2. Solar geoengineering is a bandaid on the symptoms, not a cure for the causes. It’s like putting out the fires caused by an arsonist wandering around with a flamethrower instead of confiscating and shutting off the flamethrower itself. Global heating would slow and stabilize if we stopped forcing more CO2 into the system.

But it’s unclear if that’s as true for oceanic carbon uptake. Between the basic acidification and Rothman’s working on extinction-level events, more might be required there.


Rothman has been asked for comments as well, and the article will be updated if he replies.

Humans May Be Accidentally Geoengineering the Oceans

Iron particles released by industrial activities are falling into the seas in greater quantities than previously thought

Humans May Be Accidentally Geoengineering the Oceans
Phytoplankton bloom in the Barents Sea. Credit: NASA; Jeff Schmaltz, MODIS Rapid Response Team

As the saying goes, what goes up must come down—and, as it turns out, a lot of what goes up comes down into the world’s oceans.

Iron particles, released by human industrial activities, are one example of a pollutant that goes into the atmosphere and eventually settles into the sea. Now, new research suggests that human-emitted iron is accumulating in the ocean in much greater quantities than scientists previously estimated. And it may also be dissolving into the water more easily than suspected.

The consequences are still unclear, but they’re worth investigating, scientists say. Iron is one of the key nutrients that tiny phytoplankton organisms in the ocean need to thrive. In regions where its levels are limited, adding more iron to the water can give plankton a boost, potentially altering both marine food webs and the ocean’s carbon uptake.

When the phytoplankton die, those that don’t get eaten by other animals fall through the water column and become trapped at the bottom of the sea, effectively locking away the stored-up carbon for good.

To date, various research groups have conducted more than a dozen small-scale iron fertilization experiments, with somewhat mixed results. Some studies suggest that the carbon-storing effects are more significant than others. At the same time, some experts have expressed concern that iron fertilization could have unforeseen consequences on marine ecosystems. Others say more research is needed.

Now, the new study would seem to suggest that humans may already be engaging in a kind of inadvertent iron fertilization campaign. But whether it’s having any significant effect on marine ecosystems or carbon storage is still unknown.

The study, led by Tim Conway of the University of South Florida, set out to investigate the difference between iron inputs from natural sources and iron from human activities.

Scientists have long known that dust from the Sahara, swept by winds into the sea, tends to be rich in iron and accounts for a great deal of the iron particles that wind up in the Atlantic Ocean. Iron input from anthropogenic sources, like the burning of fossil fuels and other industrial activities, is believed to be comparatively much lower.

The new study investigated the issue by chemically analyzing iron samples from the North Atlantic. Aerosols from dust and from human sources tend to have slightly different chemical fingerprints, related to the ratio of iron isotopes they contain.

The analyses suggested that human sources of iron are probably significantly higher than previous studies have estimated. The study also found that these human iron inputs likely dissolve into the water much more easily than iron from natural sources, making them more readily accessible to hungry phytoplankton.

The researchers used their observations to tweak certain model simulations of the entire global ocean. The adjusted simulations seem to suggest that the findings don’t apply only to the North Atlantic: Human iron inputs may be higher in other regions of the world, as well, including iron-limited parts of the Pacific Ocean.

That’s important because some parts of the ocean are likely more sensitive to iron fertilization than others. In the North Atlantic, for instance, the growth of phytoplankton tends to be limited by nutrients other than iron, meaning that adding more iron to the water probably won’t give them that much of a boost.

In places like the equatorial Pacific, the North Pacific and the remote Southern Ocean, on the other hand, iron is more likely to be the limiting factor. If iron inputs are on the rise in these places—especially if they’re easily dissolvable in the water—then plankton communities could theoretically increase in growth.

These effects could become even more pronounced in the future, as increased industrialization across the Asian continent and parts of the Southern Hemisphere produces more air pollution, said Douglas Hamilton, a postdoctoral researcher at Cornell University and a co-author on the new study.

For the time being, though, it’s unclear what effect human iron inputs are actually having. The first step would be to actually verify, with on-site observations, that human iron inputs are higher than expected in places besides the North Atlantic. The new study now provides a framework for doing that kind of work, Hamilton noted.

Afterward, extended monitoring could determine whether these regions are experiencing any ecological changes, like an increase in phytoplankton.

Still, it might be difficult to tease out whether those kinds of changes are being caused by increased iron fertilization or by other environmental disturbances, like ocean warming driven by climate change. In other words, even if humans are indeed engaging in an accidental iron fertilization experiment, scientists may find it challenging to determine just what effect it’s having on the Earth.

But Hamilton is hopeful that there may be ways to start addressing that question in the future. He’s working on improving model simulations of plankton productivity in the ocean, which may help scientists get a better handle on how changes to ocean chemistry may affect marine systems.

A GEOENGINEERING OPTION

Scientists have been exploring the possible effects of iron fertilization as a form of geoengineering for at least 15 years. In that time, various research groups have conducted at least 13 experiments in both natural and controlled environments, according to a 2016 review paper.

Scientists are still debating how useful the process could be for climate mitigation.

As the review paper notes, studies have generally demonstrated that iron fertilization does boost the growth of plankton in iron-limited waters. The remote Southern Ocean is the region that most researchers suggest would be best suited for iron fertilization.

But just how much carbon is actually getting stored away at the bottom of the ocean is less clear. Some research has suggested that the carbon-sequestering effects are minimal, while other experiments suggest a stronger impact.

Even in the best-case scenario, the overall climate impact of iron fertilization would likely be small, according to Christine Klaas, a researcher with the Alfred-Wegener Institute for Polar and Marine Research who has participated in past iron fertilization experiments.

“The rough estimates of how much carbon we could take away by fertilizing most of the Southern Ocean are around 1 gigaton per year, and our current emissions are around 11 gigatons per year,” she pointed out. “So it would be around 10% of what we’re emitting today.”

That means that iron fertilization, like other forms of geoengineering, isn’t a solution to the climate problem, she added. It’s one potential tool that could help bring emissions down faster, but it’s not a substitute for the urgent need to reduce greenhouse gas emissions worldwide.

The concept hasn’t been without its controversies.

Some experts have cautioned that inducing phytoplankton blooms could lead to unintended consequences for marine ecosystems, either by inadvertently triggering toxic algae blooms or by altering marine food webs in unexpected ways. Other scientists, including Klaas, point out that the ideal fertilization sites in places like the Southern Ocean don’t support many toxic species in the first place.

The idea of iron fertilization has become somewhat more contentious in recent years, after U.S. entrepreneur Russ George conducted a fertilization experiment that dumped about 100 tons of iron dust off the coast of British Columbia. The project was aimed at boosting salmon populations through its effects on the marine food web.

Iron fertilization experiments today are subject to certain regulations under the London Convention on the Prevention of Marine Pollution. Whether scientists should continue with them is still a matter of debate among experts.

Klaas is an advocate of continued research. Current efforts to reduce global greenhouse gas emissions are not proceeding quickly enough to meet the Paris climate agreement’s targets, meaning it’s increasingly likely that some form of geoengineering will be necessary to keep warming in check, she said.

Among the geoengineering options that have been proposed so far, she considers iron fertilization “one of the best” and a relatively simple process.

Hamilton, on the other hand, said that “it’s better not to even go there.”

“I think history has shown us that when we start tinkering with the environment, invariably things that we have not considered crop up,” he said. “There’s unknown unknowns in the system. This would be absolutely the case with any of the geoengineering options being talked about at the moment.”

But as long as industrial activity is causing inadvertent iron fertilization anyway, he noted, the new study may be a good starting point for understanding the effects that it’s already having on the global oceans.

“Before this study, we had no way to be able to measure the anthropogenic component in situ,” he said. “To be able to understand the anthropogenic perturbations to the system, we need to be able to measure it.

“Moving forward now, the idea, ideally, is that we measure this in locations that we know are going to be sensitive to the changes in the iron emissions due to anthropogenic activity in the future, so that we can have a handle on how much we’re perturbing that system.”

Microplastics Have Invaded The Deep Ocean — And The Food Chain

Audio will be available later today.

The deep ocean is filled with sea creatures like giant larvaceans. They’re actually the size of tadpoles, but they’re surrounded by a yard-wide bubble of mucus that collects food — and plastic.

Courtesy of the Monterey Bay Aquarium Research Institute

The largest habitat for life on Earth is the deep ocean. It’s home to everything from jellyfish to giant bluefin tuna. But the deep ocean is being invaded by tiny pieces of plastic — plastic that people thought was mostly floating at the surface, and in amounts they never imagined.

Very few people have looked for microplastic concentrations at mid- to deep-ocean depths. But there’s a place along the California coast where it’s relatively easy: The edge of the continent takes a steep dive into the deep ocean at Monterey Bay. Whales and white sharks swim these depths just a few miles offshore.

The Monterey Bay Aquarium Research Institute perches on the shoreline. At an MBARI dock, you can see one of their most sophisticated tools for doing that: a multimillion-dollar machine called Ventana sitting on the deck of the research vessel Rachel Carson. “It’s a massive underwater robot,” explains Kyle Van Houtan, chief scientist with the Monterey Bay Aquarium, which collaborates with MBARI. “Robotic arms, a lot of sensors, machinery, lights, video cameras.”

Marine biologist Anela Choy was lead scientists with the team researching microplastics on the research vessel Rachel Carson.

Courtesy of the Monterey Bay Aquarium Research Institute

The team they created has been sending Ventana up to 3,000 feet deep into the Bay in search of plastic.

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“The deep ocean is the largest ecosystem on the planet,” says Van Houtan, “and we don’t know anything about the plastic in the deep ocean.” Scientists do know about plastic floating on the surface, and have tried to measure how much there is. The Great Pacific garbage patch is just one of many giant eddies in the oceans where enormous amounts of plastic waste collects.

But beneath the surface? Not much. So Ventana made several dives to collect water samples at different depths. Technicians filtered the water, looking for microplastic, the tiny fragments and fibers you can barely see.

“What we found was actually pretty surprising,” Van Houtan says. “We found that most of the plastic is below the surface.” More, he says, than in the giant floating patches.

And also to their surprise, they found that submerged microplastics are widely distributed, from the surface to thousands of feet deep.

The Ventana is traveling up to 3,000 feet deep into the Monterey Bay in California, taking samples from sea creatures like larvaceans.

Courtesy of the Monterey Bay Aquarium Research Institute

Moreover, the farther from shore they sampled, the more microplastics they found. That suggests it’s not just washing off the California coast. It’s coming from all over.

“We think the California current is actually carrying some of the microplastic debris from the north Pacific Ocean,” he says — kind of like trash washing down off a landfill that’s actually in the ocean.

And that trash gets eaten. Marine biologist Anela Choy is an assistant professor at the Scripps Institution of Oceanography in San Diego and was lead scientist on the study. She says the deep ocean is like a giant feeding trough. “It’s filled with animals,” she says, “and they’re not only moving up and down in the water column every day, forming the biggest migration on the planet, but they’re also feasting upon one another.”

For example, the deep ocean is filled with sea creatures like larvaceans that filter tiny organisms out of the water. They’re the size of tadpoles, but they’re called “giant larvaceans” because they build a yard-wide bubble of mucus around themselves — “snot houses,” Choy calls them. The mucus captures floating plankton. But it also captures plastic. “We found small plastic pieces in every single larvacean that we examined from different depths across the water column,” Choy says. Another filter feeder, the red crab, also contained plastic pieces — every one they caught.

Choy also has looked beyond Monterey Bay and higher up the food chain. In earlier research she did in the Pacific, she collected creatures called lancetfish — several feet long, with huge mouths and lots of saber-sharp teeth. They’re called the “dragons of the deep.”

Researchers found plastic in the stomachs of one out of every three lancetfish they studied.

David Shale/Nature Picture Library/Getty Images

“We’ve looked now at over 2,000 lancetfish,” says Choy, “and we’ve found that about one in every three lancetfish has some kind of plastic in its stomach. It’s really shocking, because this fish actually doesn’t come to the surface as far as we know.” That suggests that plastic has spread through the water column.

Bruce Robison, a senior scientist with the Monterey Bay Aquarium Research Institute, says he was shocked at how much plastic they found. “The fact that plastics are so pervasive, that they are so widespread, is a staggering discovery, and we’d be foolish to ignore that,” he says. “Anything that humans introduce to that habitat is passing though these animals and being incorporated into the food web” — a web that leads up to marine animals people eat.

The Monterey Bay findings appear Thursday in the journal Nature Scientific Reportsand only represent a local sample. But Robison says 70 years of manufacturing plastic may have created a global ocean problem. “We humans are constantly coming up with marvelous ideas that eventually turn around and bite us on the butt,” he says with a dry laugh.

And scientists are just beginning to diagnose the extent of that wound.

‘Nuclear Coffin’ Leaking Radioactive Waste Into Pacific Ocean, U.N. Warns

Reuters

A Cold War-era concrete “coffin” brimming with atomic waste is leaking radioactive material into the Pacific Ocean, United Nations Secretary General Antonio Guterres warned. The dome was built to contain the nuclear waste that was created when the U.S. and France conducted atomic tests in the Pacific between 1946 and 1958. “The Pacific was victimized in the past as we all know,” said Guterres, according to AFP. The structure is on the Enewetak Atoll in the Marshall Islands; Guterres described the dome as “a kind of coffin” designed to contain nuclear material. Thousands of indigenous island people were evacuated or exposed to radioactive fallout when the U.S. carried out dozens of nuclear weapons tests in the area. The bombs tested included the 1954 Bravo hydrogen bomb, which was 1,000 times stronger than the atomic bomb dropped on Hiroshima.

Ocean acidification ‘could have consequences for millions’

UNIVERSITY OF PLYMOUTH

Ocean acidification could have serious consequences for the millions of people globally whose lives depend on coastal protection, fisheries and aquaculture, a new publication suggests.

Writing in Emerging Topics in Life Sciences, scientists say that only significant cuts in fossil fuel emissions will prevent the changes already evident in areas with projected future carbon dioxide levels becoming more widespread.

They also call for a binding international agreement that builds on the United Nations Sustainable Development Goals to minimise and address the impacts of ocean acidification.

The article was written by Jason Hall-Spencer, Professor of Marine Biology at the University of Plymouth, and Plymouth graduate Dr Ben Harvey, now Assistant Professor at the University of Tsukuba’s Shimoda Marine Research Center.

They and other collaborators have published several studies over the past decade that show the threats posed by ocean acidification in terms of habitat degradation and a loss of biodiversity.

These have centred around the coast of Japan, where they demonstrated ocean acidification is having a major impact on marine life, and in the Mediterranean where they showed it was having a negative impact on wild fish.

Both regions have volcanic CO2 seeps, where the escaping gas dissolves into the sea water and creates conditions similar to that expected to occur worldwide in the coming years.

Their new publication provides a synthesis of the likely effects of ocean acidification on ecosystem properties, functions and services and is based on laboratory experiments and observations along natural gradients in CO2.

It says that studies at CO2 seeps worldwide have shown that reefs made by organisms with shells or skeletons, such oysters or corals, are sensitive to ocean acidification and that degraded reefs provide less coastal protection and less habitat for commercially important fish and shellfish.

This amplifies the risks to marine goods and services from climate change causing shifts to seaweed dominance, habitat degradation and a loss of biodiversity in the tropics, the sub-tropics and on temperate coasts.

Dr Harvey, who graduated from the BSc (Hons) Ocean Science programme in 2008, said: “We are releasing around 1 million tons of carbon dioxide per hour into the Earth’s atmosphere. About 25% of this gas is taken up by the ocean where it reacts with seawater to form a weak acid, causing surface ocean pH to fall by around 0.002 units per year. The chemistry of this rapid change in surface waters is understood, yet there is uncertainty about its effects on society which is what we are trying to overcome in this study.”

Professor Hall-Spencer, the publication’s lead author, added said: “The Paris Agreement on climate change was welcome. But it does not mention ocean acidification, nor the fact that this rapid change in surface ocean chemistry undermines the social, economic and environmental pillars of sustainable development. The time is ripe for a ‘Paris Agreement for the oceans’, with the specific target to minimise and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels.”

Protecting Sea Creatures Could Help Slow Climate Change

As the prospect of catastrophic effects from climate change becomes increasingly likely, a search is on for innovative ways to reduce the risks. One potentially powerful and low-cost strategy is to recognize and protect natural carbon sinks – places and processes that store carbon, keeping it out of Earth’s atmosphere.

Forests and wetlands can capture and store large quantities of carbon. These ecosystems are included in climate change adaptation and mitigation strategies that 28 countries have pledged to adopt to fulfill the Paris Climate Agreement. So far, however, no such policy has been created to protect carbon storage in the ocean, which is Earth’s largest carbon sink and a central element of our planet’s climate cycle.

As a marine biologist, my research focuses on marine mammal behavior, ecology and conservation. Now I also am studying how climate change is affecting marine mammals – and how marine life could become part of the solution.

What is Marine Vertebrate Carbon?

Marine animals can sequester carbon through a range of natural processes that include storing carbon in their bodies, excreting carbon-rich waste products that sink into the deep sea, and fertilizing or protecting marine plants. In particular, scientists are beginning to recognize that vertebrates, such as fish, seabirds and marine mammals, have the potential to help lock away carbon from the atmosphere.

I am currently working with colleagues at UN Environment/GRID-Arendal, a United Nations Environment Programme center in Norway, to identify mechanisms through which marine vertebrates’ natural biological processes may be able to help mitigate climate change. So far we have found at least nine examples.

One of my favorites is Trophic Cascade Carbon. Trophic cascades occur when change at the top of a food chain causes downstream changes to the rest of the chain. As an example, sea otters are top predators in the North Pacific, feeding on sea urchins. In turn, sea urchins eat kelp, a brown seaweed that grows on rocky reefs near shore. Importantly, kelp stores carbon. Increasing the number of sea otters reduces sea urchin populations, which allows kelp forests to grow and trap more carbon.

Scientists have identified nine mechanisms through which marine vertebrates play roles in the oceanic carbon cycle.
Scientists have identified nine mechanisms through which marine vertebrates play roles in the oceanic carbon cycle.
GRID ARENDALCC BY-ND

Carbon stored in living organisms is called Biomass Carbon, and is found in all marine vertebrates. Large animals such as whales, which may weigh up to 50 tons and live for over 200 years, can store large quantities of carbon for long periods of time.

When they die, their carcasses sink to the seafloor, bringing a lifetime of trapped carbon with them. This is called Deadfall Carbon. On the deep seafloor, it can be eventually buried in sediments and potentially locked away from the atmosphere for millions of years.

Whales can also help to trap carbon by stimulating production of tiny marine plants called phytoplankton, which use sunlight and carbon dioxide to make plant tissue just like plants on land. The whales feed at depth, then release buoyant, nutrient-rich fecal plumes while resting at the surface, which can fertilize phytoplankton in a process that marine scientists call the Whale Pump.

And whales redistribute nutrients geographically, in a sequence we refer to as the Great Whale Conveyor Belt. They take in nutrients while feeding at high latitudes then release these nutrients while fasting on low-latitude breeding grounds, which are typically nutrient-poor. Influxes of nutrients from whale waste products such as urea can help to stimulate phytoplankton growth.

Finally, whales can bring nutrients to phytoplankton simply by swimming throughout the water column and mixing nutrients towards the surface, an effect researchers term Biomixing Carbon.

Fish poo also plays a role in trapping carbon. Some fish migrate up and down through the water column each day, swimming toward the surface to feed at night and descending to deeper waters by day. Here they release carbon-rich fecal pellets that can sink rapidly. This is called Twilight Zone Carbon.

These fish may descend to depths of 1,000 feet or more, and their fecal pellets can sink even farther. Twilight Zone Carbon can potentially be locked away for tens to hundreds of years because it takes a long time for water at these depths to recirculate back towards the surface.

Quantifying Marine Vertebrate Carbon

To treat “blue carbon” associated with marine vertebrates as a carbon sink, scientists need to measure it. One of the first studies in this field, published in 2010, described the Whale Pump in the Southern Ocean, estimating that a historic pre-whaling population of 120,000 sperm whales could have trapped 2.2 million tons of carbon yearly through whale poo.

Another 2010 study calculated that the global pre-whaling population of approximately 2.5 million great whales would have exported nearly 210,000 tons of carbon per year to the deep sea through Deadfall Carbon. That’s equivalent to taking roughly 150,000 cars off the road each year.

A 2012 study found that by eating sea urchins, sea otters could potentially help to trap 150,000 to 22 million tons of carbon per year in kelp forests. Even more strikingly, a 2013 study described the potential for lanternfish and other Twilight Zone fish off the western U.S. coast to store over 30 million tons of carbon per year in their fecal pellets.

Scientific understanding of marine vertebrate carbon is still in its infancy. Most of the carbon-trapping mechanisms that we have identified are based on limited studies, and can be refined with further research. So far, researchers have examined the carbon-trapping abilities of less than 1% of all marine vertebrate species.

A New Basis for Marine Conservation

Many governments and organizations around the world are working to rebuild global fish stocks, prevent bycatch and illegal fishing, reduce pollution and establish marine protected areas. If we can recognize the value of marine vertebrate carbon, many of these policies could qualify as climate change mitigation strategies.

In a step in this direction, the International Whaling Commission passed two resolutions in 2018 that recognized whales’ value for carbon storage. As science advances in this field, protecting marine vertebrate carbon stocks ultimately might become part of national pledges to fulfill the Paris Agreement.

Marine vertebrates are valuable for many reasons, from maintaining healthy ecosystems to providing us with a sense of awe and wonder. Protecting them will help ensure that the ocean can continue to provide humans with food, oxygen, recreation and natural beauty, as well as carbon storage.

Steven Lutz, Blue Carbon Programme leader at GRID-Arendal, contributed to this article.

Sea Creatures Store Carbon in the Ocean – Could Protecting Them Help Slow Climate Change?

April 17, 2019
File 20190415 147502 15sm3nq.jpg?ixlib=rb 1.1
A sperm whale goes down for a dive off Kaikoura, New Zealand. (Photo by Heidi Pearson, CC BY-ND)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

As the prospect of catastrophic effects from climate change becomes increasingly likely, a search is on for innovative ways to reduce the risks. One potentially powerful and low-cost strategy is to recognize and protect natural carbon sinks – places and processes that store carbon, keeping it out of Earth’s atmosphere.

Forests and wetlands can capture and store large quantities of carbon. These ecosystems are included in climate change adaptation and mitigation strategies that 28 countries have pledged to adopt to fulfill the Paris Climate Agreement. So far, however, no such policy has been created to protect carbon storage in the ocean, which is Earth’s largest carbon sink and a central element of our planet’s climate cycle.

As a marine biologist, my research focuses on marine mammal behavior, ecology and conservation. Now I also am studying how climate change is affecting marine mammals – and how marine life could become part of the solution.

A sea otter rests in a kelp forest off California. By feeding on sea urchins, which eat kelp, otters help kelp forests spread and store carbon. (Photo by Nicole LaRoche, CC BY-ND)

What is marine vertebrate carbon?

Marine animals can sequester carbon through a range of natural processes that include storing carbon in their bodies, excreting carbon-rich waste products that sink into the deep sea, and fertilizing or protecting marine plants. In particular, scientists are beginning to recognize that vertebrates, such as fish, seabirds and marine mammals, have the potential to help lock away carbon from the atmosphere.

I am currently working with colleagues at UN Environment/GRID-Arendal, a United Nations Environment Programme center in Norway, to identify mechanisms through which marine vertebrates’ natural biological processes may be able to help mitigate climate change. So far we have found at least nine examples.

One of my favorites is Trophic Cascade Carbon. Trophic cascades occur when change at the top of a food chain causes downstream changes to the rest of the chain. As an example, sea otters are top predators in the North Pacific, feeding on sea urchins. In turn, sea urchins eat kelp, a brown seaweed that grows on rocky reefs near shore. Importantly, kelp stores carbon. Increasing the number of sea otters reduces sea urchin populations, which allows kelp forests to grow and trap more carbon.

Scientists have identified nine mechanisms through which marine vertebrates play roles in the oceanic carbon cycle. (Image by GRID ArendalCC BY-ND)

Carbon stored in living organisms is called Biomass Carbon, and is found in all marine vertebrates. Large animals such as whales, which may weigh up to 50 tons and live for over 200 years, can store large quantities of carbon for long periods of time.

When they die, their carcasses sink to the seafloor, bringing a lifetime of trapped carbon with them. This is called Deadfall Carbon. On the deep seafloor, it can be eventually buried in sediments and potentially locked away from the atmosphere for millions of years.

Whales can also help to trap carbon by stimulating production of tiny marine plants called phytoplankton, which use sunlight and carbon dioxide to make plant tissue just like plants on land. The whales feed at depth, then release buoyant, nutrient-rich fecal plumes while resting at the surface, which can fertilize phytoplankton in a process that marine scientists call the Whale Pump.

And whales redistribute nutrients geographically, in a sequence we refer to as the Great Whale Conveyor Belt. They take in nutrients while feeding at high latitudes then release these nutrients while fasting on low-latitude breeding grounds, which are typically nutrient-poor. Influxes of nutrients from whale waste products such as urea can help to stimulate phytoplankton growth.

Finally, whales can bring nutrients to phytoplankton simply by swimming throughout the water column and mixing nutrients towards the surface, an effect researchers term Biomixing Carbon.

Fish poo also plays a role in trapping carbon. Some fish migrate up and down through the water column each day, swimming toward the surface to feed at night and descending to deeper waters by day. Here they release carbon-rich fecal pellets that can sink rapidly. This is called Twilight Zone Carbon.

These fish may descend to depths of 1,000 feet or more, and their fecal pellets can sink even farther. Twilight Zone Carbon can potentially be locked away for tens to hundreds of years because it takes a long time for water at these depths to recirculate back towards the surface.

‘Marine snow’ is made up of fecal pellets and other bits of organic material that sink into deep ocean waters, carrying large quantities of carbon into the depths.

Quantifying marine vertebrate carbon

To treat “blue carbon” associated with marine vertebrates as a carbon sink, scientists need to measure it. One of the first studies in this field, published in 2010, described the Whale Pump in the Southern Ocean, estimating that a historic pre-whaling population of 120,000 sperm whales could have trapped 2.2 million tons of carbon yearly through whale poo.

Another 2010 study calculated that the global pre-whaling population of approximately 2.5 million great whales would have exported nearly 210,000 tons of carbon per year to the deep sea through Deadfall Carbon. That’s equivalent to taking roughly 150,000 cars off the road each year.

A 2012 study found that by eating sea urchins, sea otters could potentially help to trap 150,000 to 22 million tons of carbon per year in kelp forests. Even more strikingly, a 2013 study described the potential for lanternfish and other Twilight Zone fish off the western U.S. coast to store over 30 million tons of carbon per year in their fecal pellets.

Scientific understanding of marine vertebrate carbon is still in its infancy. Most of the carbon-trapping mechanisms that we have identified are based on limited studies, and can be refined with further research. So far, researchers have examined the carbon-trapping abilities of less than 1% of all marine vertebrate species.

The brownish water at the base of this humpback whale’s fluke is a fecal plume, which can fertilize phytoplankton near the surface. Photo taken under NMFS permit 10018-01. (Photo by Heidi Pearson, CC BY-ND)

A new basis for marine conservation

Many governments and organizations around the world are working to rebuild global fish stocks, prevent bycatch and illegal fishing, reduce pollution and establish marine protected areas. If we can recognize the value of marine vertebrate carbon, many of these policies could qualify as climate change mitigation strategies.

In a step in this direction, the International Whaling Commission passed two resolutions in 2018 that recognized whales’ value for carbon storage. As science advances in this field, protecting marine vertebrate carbon stocks ultimately might become part of national pledges to fulfill the Paris Agreement.

Marine vertebrates are valuable for many reasons, from maintaining healthy ecosystems to providing us with a sense of awe and wonder. Protecting them will help ensure that the ocean can continue to provide humans with food, oxygen, recreation and natural beauty, as well as carbon storage.

Many sharks closer to extinction than feared

: Red List

Marlowe Hood

Agence France-Presse
Paris / Mon, March 25, 2019 / 09:00 pm
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A picture of mako shark. Seventeen of 58 species evaluated were classified as facing extinction, the Shark Specialist Group of the International Union for the Conservation (IUCN) said late Thursday in an update of the Red List of threatened animals and plants.
(Shutterstock/saulty72)

Human appetites are pushing makos and other iconic sharks to the brink of extinction, scientists warned in a new assessment of the apex predator’s conservation status.

Seventeen of 58 species evaluated were classified as facing extinction, the Shark Specialist Group of the International Union for the Conservation (IUCN) said late Thursday in an update of the Red List of threatened animals and plants.

“Our results are alarming,” said Nicholas Dulvy, who chairs the grouping of 174 experts from 55 countries.

“The sharks that are especially slow-growing, sought-after and unprotected from overfishing tend to be the most threatened.”

That category includes the shortfin mako, whose cruising speed of 40 km/h (25 mph) — punctuated by bursts of more than 70 km/h — makes it the fastest of all sharks.

Along with its longfin cousin, the two makos are highly prized for their flesh and fins, considered a delicacy in Chinese and other Asian culinary traditions.

“Today, one of the biggest shark fisheries on the high seas is the mako,” Dulvy told AFP. “It is also one of the least protected.”

In May, nations will vote on a proposal by Mexico to list the shortfin mako on Appendix II of CITES, the Convention on International Trade in Endangered Species.

An Appendix II status would not ban fishing or trade, but would regulate it.

Six of the species reviewed were listed as “critically endangered,”
three for the first time: the whitefin swellshark, the Argentine angel shark, and the smoothback angel shark.

Eleven others were classified as either “endangered” or “vulnerable” to extinction.

The IUCN’s shark group is conducting a two-year review of more than 400 species of sharks.

Read also: ‘They’re all dead’: 110 captive sharks in Karimunjawa die mysteriously

For land animals, conservation biologists focus on population size and geographic range in assessing extinction threat.

For sharks and other marine animals they use another approach, looking instead at how quickly populations decline.

‘Way worse than thought’

But that requires a benchmark, especially for pelagic — or open ocean
— species, Dulvy explained.

Only within the last 10 years have scientists been able to establish one, partly with the help of tuna fisheries that began to keep tallies of sharks by-catch.

“A decade on, we now know that the situation is way worse than we ever thought,” Dulvy said.

Ironically, fisheries management organisations doing a better job policing tuna catches has increased the incentive for fishermen to target sharks for extra income.

“In the Indian Ocean” — along coastlines in the Arabian Sea and the Bay of Bengal — “the tuna fishery is really a shark fishery with tuna by-catch,” Dulvy said.

In light of its new findings, the Shark Specialist Group is calling for “immediate national and international fishing limits, including complete bans on landing those species assessed as ‘endangered’ or ‘critically endangered’,” said Sonja Fordham, deputy chair of the group and an officer at The Ocean Foundation.

Sharks have lorded over the world’s oceans for some 400 million years, playing a critical role in global food chains.

But the top-level predators have proven especially vulnerable to human
predation: they grow slowly, become sexually mature relatively late in life, and produce few offspring.

The greeneye spurdog — newly classified as endangered — has a gestation period of nearly three years, the longest in the animal kingdom.

A 2013 peer-review study estimated that upward of 100 million sharks are fished every year to satisfy a market for their fins, meat, and liver oil.

More than half of shark species and their relatives are categorised as threatened or near-threatened with extinction.

https://www.thejakartapost.com/life/2019/03/25/sharks-closer-to-extinction-red-list.html

Undersea gases could superheat the planet

Carbon reservoirs on ocean floor caused global warming before — and could do it again

Date:
February 13, 2019
Source:
University of Southern California
Summary:
Geologic carbon and hydrate reservoirs in the ocean pose a climate threat beyond humanmade greenhouse gases.
Share:
FULL STORY

A deep-sea reservoir near Taiwan spews carbon dioxide when its slurry-like hydrate cap ruptures.
Credit: National Academy of Sciences

The world’s oceans could harbor an unpleasant surprise for global warming, based on new research that shows how naturally occurring carbon gases trapped in reservoirs atop the seafloor escaped to superheat the planet in prehistory.

Scientists say events that began on the ocean bottom thousands of years ago so disrupted the Earth’s atmosphere that it melted away the ice age. Those new findings challenge a long-standing paradigm that ocean water alone regulated carbon dioxide in the atmosphere during glacial cycles. Instead, the study shows geologic processes can dramatically upset the carbon cycle and cause global change.

For today’s world, the findings could portend an ominous development. The undersea carbon reservoirs released greenhouse gas to the atmosphere as oceans warmed, the study shows, and today the ocean is heating up again due to humanmade global warming.

If undersea carbon reservoirs are upset again, they would emit a huge new source of greenhouse gases, exacerbating climate change. Temperature increases in the ocean are on pace to reach that tipping point by the end of the century. For example, a big carbon reservoir beneath the western Pacific near Taiwan is already within a few degrees Celsius of destabilizing.

Moreover, the phenomenon is a threat unaccounted for in climate model projections. Undersea carbon dioxide reservoirs are relatively recent discoveries and their characteristics and history are only beginning to be understood.

Those findings come from a new research paper produced by an international team of Earth scientists led by USC and published in January in the journal Environmental Research Letters.

“We’re using the past as a way to anticipate the future,” said Lowell Stott, professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences and lead author of the study. “We know there are vast reservoirs of carbon gas at the bottom of the oceans. We know when they were disrupted during the Pleistocene it warmed the planet.

“We have to know if these carbon reservoirs could be destabilized again. It’s a wild card for which we need to account,” Stott said.

At issue are expanses of carbon dioxide and methane accumulating underwater and scattered across the seafloor. They form as volcanic activity releases heat and gases that can congeal into liquid and solid hydrates, which are compounds stuck together in an icy slurry that encapsulates the reservoirs.

These undersea carbon reservoirs largely stay put unless perturbed, but the new study shows the natural reservoirs are vulnerable in a warming ocean and provides proof the Earth’s climate has been affected by rapid release of geologic carbon.

The scientists say it occurred in the distant past when the Earth was much warmer, and it’s happened more recently — about 17,000 years ago at the end of the Pleistocene epoch when glaciers advanced and receded, which is the focus on the new study. Warming was evident due to changes in atmospheric greenhouse gas concentrations, based on ice cores, marine and continental records.

But how did that happen? What forced such dramatic change in the first place? Scientists have been searching for that answer for 40 years, with focus on oceans because they’re a giant carbon sink and play a central role in carbon dioxide variations.

They soon realized that processes that regulate carbon to the ocean operated too slowly to account for the surge in atmospheric greenhouse gases that led to warming that ended the ice age. So, scientists around the world began examining the role of Earth’s hydrothermal systems and their impact on deep-ocean carbon to see how it affected the atmosphere.

The new study by scientists at USC, the Australian National University and Lund University in Sweden, focused on the Eastern Equatorial Pacific (EEP) hundreds of miles off the coast of Ecuador. The EEP is a primary conduit through which the ocean releases carbon to the atmosphere.

The scientists report evidence of deep-sea hydrothermal systems releasing greenhouse gases to the ocean and atmosphere at the end of the last ice age, just as the oceans were beginning to warm. They measured increased deposition of hydrothermal metals in ancient marine sediments. They correlated glaciation intervals with variations in atmospheric carbon dioxide with differences in marine microorganism ages. They found a four-fold increase in zinc in protozoa (foraminifera) shells, a telltale sign of widespread hydrothermal activity.

Taken together, the new data show that there were major releases of naturally occurring carbon from the EEP, which contributed to dramatic change in Earth’s temperature as the ice age was ending, the study says.

Elsewhere around the world, more and more deep-ocean carbon reservoirs are being discovered. They mostly occur near hydrothermal vents, of which scores have been identified so far, especially in the Pacific, Atlantic and Indian oceans. They occur where the Earth’s crust spreads or collides, creating ideal conditions for the formation of deep-sea carbon dioxide reservoirs. Only about one-third of the ocean’s volcanic regions have been surveyed.

One such reservoir of undersea carbon dioxide, seen in the accompanying video, was discovered about 4,000 feet deep off the coast of Taiwan. Similar discoveries of carbon gas reservoirs have been made off the coast of Okinawa, in the Aegean Sea, in the Gulf of California and off the west coast of Canada.

“The grand challenge is we don’t have estimates of the size of these or which ones are particularly vulnerable to destabilization,” Stott said. “It’s something that needs to be determined.”

In many cases, the carbon reservoirs are bottled up by their hydrate caps. But those covers are sensitive to temperature changes. As oceans warm, the caps can melt, a development the paper warns would lead to a double wallop for climate change — a new source of geologic carbon in addition to the humanmade greenhouse gases.

Oceans absorb nearly all the excess energy from the Earth’s atmosphere, and as a result they have been warming rapidly in recent decades. Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, other studies have shown. Throughout the marine water column, ocean heat has increased for the last 50 years. The federal government’s Climate Science Special Report projected a global increase in average sea surface temperatures of up to 5 degrees Fahrenheit by the end of the century, given current emissions rates. Temperature gains of that magnitude throughout the ocean could eventually destabilize the geologic hydrate reservoirs, Stott said.

“The last time it happened, climate change was so great it caused the end of the ice age. Once that geologic process begins, we can’t turn it off,” Stott said.

Moreover, other similar events have happened in the distant past, helping shape the Earth’s environment over and over again. In earlier research, Stott discovered a large, carbon anomaly that occurred 55 million years ago. It disrupted the ocean’s chemistry, causing extensive dissolution of marine carbonates and the extinction of many marine organisms. The ocean changes were accompanied by a rapid rise in global temperatures, an event called the Paleocene-Eocene Thermal Maxima (PETM), a period lasting less than 20,000 years during which so much carbon was released to the atmosphere that Earth’s temperatures surged to about 8 degrees Celsius hotter than today.

“Until quite recently, we had no idea these events occurred. The PETM event is a good analog for what can happen when undersea carbon escapes through the water column to the atmosphere. And now we know the PETM event was not a unique event, that this has happened more recently,” Stott said.

The study comes with some caveats. Much of the ocean floor is unexplored, so scientists don’t know the full extent of the carbon dioxide reservoirs. There is no inventory of greenhouse gases from these geologic sources. And ocean warming is not uniform, making it difficult to predict when and where the undersea carbon reservoirs will be affected. It would take much more study to answer those questions.

Nonetheless, the study makes clear the undersea carbon reservoirs are vulnerable to ocean warming.

“Geologic carbon reservoirs such as these are not explicitly included in current marine carbon budgets” used to model the impacts of climate change, the study says. Yet, “even if only a small percentage of the unsampled hydrothermal systems contain separate gas or liquid carbon dioxide phases, it could change the global marine carbon budget substantially.”

Said Stott: “Discoveries of accumulations of liquid, hydrate and gaseous carbon dioxide in the ocean has not been accounted for because we didn’t know these reservoirs existed until recently, and we didn’t know they affected global change in a significant ways.

“This study shows that we’ve been missing a critical component of the marine carbon budget. It shows these geologic reservoirs can release large amounts of carbon from the oceans. Our paper makes the case that this process has happened before and it could happen again.”

The study authors are Lowell Stott of USC, Kathleen M. Harazin of the Australian National University and Nadine B. Quintana Krupinski of Lund University, Sweden. U.S. funding for the study comes from a National Science Foundation Marine Geology and Geophysics Grant (1558990).

Story Source:

Materials provided by University of Southern CaliforniaNote: Content may be edited for style and length.

Undersea gases could superheat the planet

Carbon reservoirs on ocean floor caused global warming before — and could do it again

Date:
February 13, 2019
Source:
University of Southern California
Summary:
Geologic carbon and hydrate reservoirs in the ocean pose a climate threat beyond humanmade greenhouse gases.
Share:
FULL STORY

A deep-sea reservoir near Taiwan spews carbon dioxide when its slurry-like hydrate cap ruptures.
Credit: National Academy of Sciences

The world’s oceans could harbor an unpleasant surprise for global warming, based on new research that shows how naturally occurring carbon gases trapped in reservoirs atop the seafloor escaped to superheat the planet in prehistory.

Scientists say events that began on the ocean bottom thousands of years ago so disrupted the Earth’s atmosphere that it melted away the ice age. Those new findings challenge a long-standing paradigm that ocean water alone regulated carbon dioxide in the atmosphere during glacial cycles. Instead, the study shows geologic processes can dramatically upset the carbon cycle and cause global change.

For today’s world, the findings could portend an ominous development. The undersea carbon reservoirs released greenhouse gas to the atmosphere as oceans warmed, the study shows, and today the ocean is heating up again due to humanmade global warming.

If undersea carbon reservoirs are upset again, they would emit a huge new source of greenhouse gases, exacerbating climate change. Temperature increases in the ocean are on pace to reach that tipping point by the end of the century. For example, a big carbon reservoir beneath the western Pacific near Taiwan is already within a few degrees Celsius of destabilizing.

Moreover, the phenomenon is a threat unaccounted for in climate model projections. Undersea carbon dioxide reservoirs are relatively recent discoveries and their characteristics and history are only beginning to be understood.

Those findings come from a new research paper produced by an international team of Earth scientists led by USC and published in January in the journal Environmental Research Letters.

“We’re using the past as a way to anticipate the future,” said Lowell Stott, professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences and lead author of the study. “We know there are vast reservoirs of carbon gas at the bottom of the oceans. We know when they were disrupted during the Pleistocene it warmed the planet.

“We have to know if these carbon reservoirs could be destabilized again. It’s a wild card for which we need to account,” Stott said.

At issue are expanses of carbon dioxide and methane accumulating underwater and scattered across the seafloor. They form as volcanic activity releases heat and gases that can congeal into liquid and solid hydrates, which are compounds stuck together in an icy slurry that encapsulates the reservoirs.

These undersea carbon reservoirs largely stay put unless perturbed, but the new study shows the natural reservoirs are vulnerable in a warming ocean and provides proof the Earth’s climate has been affected by rapid release of geologic carbon.

The scientists say it occurred in the distant past when the Earth was much warmer, and it’s happened more recently — about 17,000 years ago at the end of the Pleistocene epoch when glaciers advanced and receded, which is the focus on the new study. Warming was evident due to changes in atmospheric greenhouse gas concentrations, based on ice cores, marine and continental records.

But how did that happen? What forced such dramatic change in the first place? Scientists have been searching for that answer for 40 years, with focus on oceans because they’re a giant carbon sink and play a central role in carbon dioxide variations.

They soon realized that processes that regulate carbon to the ocean operated too slowly to account for the surge in atmospheric greenhouse gases that led to warming that ended the ice age. So, scientists around the world began examining the role of Earth’s hydrothermal systems and their impact on deep-ocean carbon to see how it affected the atmosphere.

The new study by scientists at USC, the Australian National University and Lund University in Sweden, focused on the Eastern Equatorial Pacific (EEP) hundreds of miles off the coast of Ecuador. The EEP is a primary conduit through which the ocean releases carbon to the atmosphere.

The scientists report evidence of deep-sea hydrothermal systems releasing greenhouse gases to the ocean and atmosphere at the end of the last ice age, just as the oceans were beginning to warm. They measured increased deposition of hydrothermal metals in ancient marine sediments. They correlated glaciation intervals with variations in atmospheric carbon dioxide with differences in marine microorganism ages. They found a four-fold increase in zinc in protozoa (foraminifera) shells, a telltale sign of widespread hydrothermal activity.

Taken together, the new data show that there were major releases of naturally occurring carbon from the EEP, which contributed to dramatic change in Earth’s temperature as the ice age was ending, the study says.

Elsewhere around the world, more and more deep-ocean carbon reservoirs are being discovered. They mostly occur near hydrothermal vents, of which scores have been identified so far, especially in the Pacific, Atlantic and Indian oceans. They occur where the Earth’s crust spreads or collides, creating ideal conditions for the formation of deep-sea carbon dioxide reservoirs. Only about one-third of the ocean’s volcanic regions have been surveyed.

One such reservoir of undersea carbon dioxide, seen in the accompanying video, was discovered about 4,000 feet deep off the coast of Taiwan. Similar discoveries of carbon gas reservoirs have been made off the coast of Okinawa, in the Aegean Sea, in the Gulf of California and off the west coast of Canada.

“The grand challenge is we don’t have estimates of the size of these or which ones are particularly vulnerable to destabilization,” Stott said. “It’s something that needs to be determined.”

In many cases, the carbon reservoirs are bottled up by their hydrate caps. But those covers are sensitive to temperature changes. As oceans warm, the caps can melt, a development the paper warns would lead to a double wallop for climate change — a new source of geologic carbon in addition to the humanmade greenhouse gases.

Oceans absorb nearly all the excess energy from the Earth’s atmosphere, and as a result they have been warming rapidly in recent decades. Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, other studies have shown. Throughout the marine water column, ocean heat has increased for the last 50 years. The federal government’s Climate Science Special Report projected a global increase in average sea surface temperatures of up to 5 degrees Fahrenheit by the end of the century, given current emissions rates. Temperature gains of that magnitude throughout the ocean could eventually destabilize the geologic hydrate reservoirs, Stott said.

“The last time it happened, climate change was so great it caused the end of the ice age. Once that geologic process begins, we can’t turn it off,” Stott said.

Moreover, other similar events have happened in the distant past, helping shape the Earth’s environment over and over again. In earlier research, Stott discovered a large, carbon anomaly that occurred 55 million years ago. It disrupted the ocean’s chemistry, causing extensive dissolution of marine carbonates and the extinction of many marine organisms. The ocean changes were accompanied by a rapid rise in global temperatures, an event called the Paleocene-Eocene Thermal Maxima (PETM), a period lasting less than 20,000 years during which so much carbon was released to the atmosphere that Earth’s temperatures surged to about 8 degrees Celsius hotter than today.

“Until quite recently, we had no idea these events occurred. The PETM event is a good analog for what can happen when undersea carbon escapes through the water column to the atmosphere. And now we know the PETM event was not a unique event, that this has happened more recently,” Stott said.

The study comes with some caveats. Much of the ocean floor is unexplored, so scientists don’t know the full extent of the carbon dioxide reservoirs. There is no inventory of greenhouse gases from these geologic sources. And ocean warming is not uniform, making it difficult to predict when and where the undersea carbon reservoirs will be affected. It would take much more study to answer those questions.

Nonetheless, the study makes clear the undersea carbon reservoirs are vulnerable to ocean warming.

“Geologic carbon reservoirs such as these are not explicitly included in current marine carbon budgets” used to model the impacts of climate change, the study says. Yet, “even if only a small percentage of the unsampled hydrothermal systems contain separate gas or liquid carbon dioxide phases, it could change the global marine carbon budget substantially.”

Said Stott: “Discoveries of accumulations of liquid, hydrate and gaseous carbon dioxide in the ocean has not been accounted for because we didn’t know these reservoirs existed until recently, and we didn’t know they affected global change in a significant ways.

“This study shows that we’ve been missing a critical component of the marine carbon budget. It shows these geologic reservoirs can release large amounts of carbon from the oceans. Our paper makes the case that this process has happened before and it could happen again.”

The study authors are Lowell Stott of USC, Kathleen M. Harazin of the Australian National University and Nadine B. Quintana Krupinski of Lund University, Sweden. U.S. funding for the study comes from a National Science Foundation Marine Geology and Geophysics Grant (1558990).