Ants May Boost CO2 Absorption Enough to Slow Global Warming

August 12, 2014 by admin  
Filed under Global Warming

What if you could build a brick fence in your backyard that would offset a portion of your daily carbon dioxide emissions, such as those produced on your drive home from work? Would you do it?

Ronald Dorn, professor of geography at Arizona State University in Tempe, would. Except the fence he has in mind wouldn’t be just constructed from any old brick. It would be coated with calcium or magnesium and inhabited by a colony of ants.

If this idea sounds bizarre to you, that’s probably because—as Dorn himself would admit—it is. Yet, he says, it is conceivable that people all over the world could one day use their own version of this mineral/ant–based method of CO2 capture to limit the gas in the atmosphere and thereby help control its global heating effects.

CO2 is currently the primary greenhouse gas emitted via human activities, according to the U.S. Environmental Protection Agency’s Overview of Green House Gases. And the volume released has only increased since the industrial revolution, contributing to global warming.

Using ants to help capture CO2 and help fight global warming stems from a study Dorn published recently in Geology linking ants to the acceleration of natural carbon dioxide absorption in rock by up to 335 times, compared with absorption in ant-free areas.

Responding to the study, David Schwartzman, emeritus professor of biogeochemistry at Howard University who reviewed but was not a part of the research, said that encouraging ant colonization “will be important in carbon sequestration” from the atmosphere.

Of course, both he and Dorn note, the ants themselves may not always be necessary once researchers learn more about how the insects promote carbon sequestration. “I don’t know if you can just have massive ant colonies hanging around a power plant. But if we know what particular secretion of an ant gland is doing this trick, or combinations of secretions,” Dorn says, then those substances could potentially be produced in quantity.

How rock captures carbon
Dorn himself is not sure how ants perform their “magic,” but he does have a good handle on how certain rocks absorb carbon on their own.

He says that rock containing calcium and magnesium naturally absorbs carbon dioxide, which in turn transforms it into carbon-rich limestone, or dolomite. This carbon capture by rock has been happening for a very long time. In fact, over geologic time it probably helped to keep the planet’s atmospheric CO2 levels and its temperature from rising too high for life to survive. Dorn’s new research suggests ants could have been responsible for helping accelerate this process.

Overall Dorn says this chemical activity really is essential to making Earth habitable. It is so important that he has his students do a rather unusual ceremony when working out in the field for research projects. “When I take students on field trips, I make them kiss the limestone, because that limestone is just CO2 that’s just locked up in rocks and how Earth has remained habitable.”

From annoyance to anomaly
Dorn discovered the contribution ants can make almost by accident. In the 1990s, as part of studying the weathering of minerals, he stuck minerals in all sorts of different areas—in soil, in bare ground, in crusts ripe with microorganisms, in ground next to roots and in a plastic tube used as a control. You name it, he did it—he wanted a baseline from which to track changes over time, he says.

At first, the ants were mainly an annoyance. “I’d drill holes and they’d bite you,” he says. It wasn’t until after putting up with them for 25 years while taking measurements of the minerals’ weathering over time that he got his first inkling of their carbon-sequestering prowess. “It was pretty clear when I started processing samples of the minerals from the different areas that the ants were incredibly anomalous,” he says, referring to just how much the ants sped up the carbon-capture process. Follow-up work then quantified the amount of carbon stored in rocks visited by ants.

And although he still isn’t sure whether it’s the ants licking the rock, their microbes, their gland secretions or something else that accounts for the carbon enhancement in rocks, he does understand further insight into the process could potentially help people do a better job of capturing carbon from the atmosphere. “I don’t understand how the ants are doing the processes,” he says. “I would love to get funding to figure this out…. Then we could move forward to work with the chemical engineers or somebody to figure out if this magic trick can be efficiently and economically used. That would be a dream.”

Schwartzman agrees and says that such carbon sequestration will be imperative in bringing down the atmospheric level of CO2 to below 350 parts per million (it is now 400 ppm) “to avoid the worst consequences of ongoing climate change induced by anthropogenic releases of CO2 to the atmosphere.” Although he added that this carbon release must also be radically and rapidly curbed as well.

Regardless, there are over 10 trillion ants on Earth, according to some estimates. So, “clearly, more studies on the role of ants and other animals populating soils are needed to broaden our understanding of their significance,” Schwartzman says.

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How Global Warming Is Dissolving Sea Life (And What We Can Do About It)

March 25, 2014 by admin  
Filed under Featured, Global Warming

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

The last time Earth’s oceans were this acidic, a six mile-wide sulphur-rich space rock had just smashed into the Yucatan Peninsula, unleashing a deluge of acid rain that exterminated all sea life in the the top 400 meters of the water column. Now, some 65 million years after the Cretaceous extinction, human activity is threatening to similarly decimate the ocean’s ecosystem—this time, from the bottom up.

How the Oceans Went Out of Whack

Under natural conditions, carbon dioxide is continuously transferred between the ocean, atmosphere, and continents in a delicately balanced process known as the carbon cycle. CO2 is pulled from the atmosphere by photosynthetic plants, which form the base of both terrestrial and oceanic food webs. It’ then subsequently sequestered in sediment when those plants—as well as the animals that feed on them—die and decompose. It’s a nice trick and it helps keep us all breathing.

Simultaneously, a roughly equivalent amount of carbon enters the atmosphere due to air-sea gas exchanges, as well as the respiration of sedimentary microbes as they decompose dead organic matter. Along with the nitrogen and water cycles, this carbon cycle is one of the primary facilitators of life on Earth, constantly recycling the limited supply of carbon that forms the base of every organism alive today.

But since the dawn of the industrial revolution, human activity—specifically, burning coal to produce energy—has upended the balance of the carbon cycle. The concentration of CO2 in the atmosphere has jumped from 280 ppm prior to industrialization to nearly 400 ppm today. We’re pouring more CO2 into the atmosphere than the system can sequester. This excess of atmospheric greenhouse gas has not only resulted in global warming but wreaked havoc on the ocean’s chemistry as well.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

When carbon dioxide enters the ocean, it reacts with seawater to create carbonic acid. This acid in turn produces a secondary reaction, splitting into separate bicarbonate and hydronium ions, which lower the water’s pH level. The more CO2 present in the atmosphere, the more gets absorbed by the oceans, and the lower the water’s pH will become.

Current scientific estimates suggest that the oceans are absorbing roughly 25 percent of the CO2 we produce each year, with another 45 percent remaining trapped in the atmosphere, and the rest being absorbed by terrestrial plants. Between 1751 and 1994, the surface ocean pH has dropped from an estimated 8.25 to 8.14. That may not seem like much but remember pH is logarithmic, just like the Richter Scale, so a .11 decrease constitutes a 30 percent increase in acidity. And if acidification rates continue at their present pace, the pH of the world’s oceans could drop another .5 units—roughly triple the acidity they are right now—by 2100. This would be cataclysmic for sea life and humanity alike.

What This Means for Sea Life

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

While an added abundance of atmospheric C02 may be a boon to plant life, the resulting acidification it causes is seriously impairing the development of oceanic calcifying organisms—everything that lives in a calcium-based shell from the phytoplankton, zooplankton, and corals that form the base of the food web to mollusks and crustaceans like clams, oysters, crabs, and lobsters.

Normally, there’s a supersaturation of carbonate ions, which these animals process into aragonite for use in their shells. However, as the pH decreases, calcium carbonate becomes more soluble which reduces the concentration of available carbonate ions. And not only does this reduce the rate at which organisms can build their protective structures, it also increases the rate at which existing shells dissolve. They’re literally being melted away by increasingly corrosive seawater.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

And it’s not just shellfish that are at risk. Decreased pH levels have been linked to a number of other adverse effects—both direct and indirect—such as the CO2-induced acidification of body fluids, known as hypercapnia, the reduced metabolism in jumbo squid, slowed embryonic development in Atlantic longfin squid, the inability of juvenile clownfish (poor Nemo!) to hear and smell approaching predators, and the diminished echolocation capacity of dolphins and whales.

Nowhere, though, is the effect more clearly illustrated than in coral. Both tropical and deep sea coral species, whose calcium carbonate homes form reefs that support entire ecosystems—acting as both nurseries for a number of commercial fish stocks as well as habitat for countless other species—are showing slower rates of growth than in the past and are suffering from the effects of coral bleaching at unprecedented levels. In 2005, for example, nearly half of the coral around the Virgin Islands and Puerto Rico were lost in a single year to mass bleaching events.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

Image: Acropora

The loss of their coral homes only serves to amplify the pressure exerted on existing fish and crustacean populations from overfishing, habitat loss, pollution, and rising sea temperatures. It won’t be long before humanity is directly affected too.

What This Means for Humans

The ocean acts as the primary source of protein for over a billion people worldwide. The US commercial fishing industry exported more than $5.1 billion of fish products in 2012 alone while providing employment for more than a million Americans. We are the fifth-largest seafood producer behind China, Peru, India, and Indonesia—catching just 3.8 percent of the global total annually.

Ocean acidification threatens to topple this industry in the near term if steps are not taken to correct it. The populations of popular shellfish like lobsters, crab, scallops, shrimp, oysters, mussels, and clams are in danger of collapse as the concentration of carbonate ions continues to decline. What’s more, the increased water acidity is doing strange things to crab stocks.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

Image: Sasha Isachenko

Alaskan Red King Crabs—the centerpiece of the Alaskan crabbing industry, which fetched $92.5 million for just 14.8 million pounds in 2011—show a 100 percent increase in larval mortality (twice as many die) when raised in acidified water, though the less sought-after dungeness crabs, which live in the same areas as King Reds, are less unaffected by the pH change. Maryland Blue crabs, on the other hand, will grow three times their average size when raised in lower pH waters and become extremely aggressive predators. Still, should these populations collapse, the damage to the regional fishing industry—not to mention the prices at your supermarket—will take decades to repair.

What We Can Do About It?

Since ocean acidification (like global warming) is the result of human activity, it therefore can be mitigated by changing the way we interact with the environment.

One obvious answer is to simply reduce the amount of CO2 we’re discharging into the air, though that is far easier said than done. While the world’s governments continue t0 work towards a political solution (see: the Kyoto Protocol) and coastal fisheries simultaneously strive to both slow the rate of acidification and adapt to changing water chemistry, there are a number of steps individuals can take to reduce their carbon footprint. And while reducing your personal carbon emissions may not make a very big impact, the actions of 6 billion individuals taken together could very well save the world. [PhysOrg - Wiki 1, 2, 3 - NOAA 1, 2, 3, 4 - NRDC - WHOI - EPA - Seattle Times - Real Science]

top image: Ethan Daniels

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