Nav: Home

UBC researchers explore an often ignored source of greenhouse gas

February 21, 2019

In a new study from UBC's Okanagan campus, researchers have discovered a surprising new source of carbon dioxide (CO2) emissions--bicarbonates hidden in the lake water used to irrigate local orchards.

"We have been studying the carbon content of soil for some time," says Melanie Jones, professor of biology and study lead author. "This large natural carbon store is hugely important in combatting rising atmospheric CO2 levels and it's essential to understand all the carbon transactions that take place in soil."

During photosynthesis, plants remove CO2 from the atmosphere and convert it into plant tissue such as roots, leaves, fruit or bark. At the same time, Jones explains, the decomposition of dead plant tissue by soil organisms, including bacteria, fungi, earthworms, ants and others, produce CO2 and release it back into the atmosphere.

Critically, some of the CO2that was removed from the atmosphere by plants can also be converted into soil organic matter by soil organisms, where it can remain in the soil for hundreds of years," says Kirsten Hannam, an agroecologist with Agriculture and Agri-Food Canada, and a co-author on the study. "So major research efforts are underway to figure out how to increase soil organic matter content."

Hannam says greater organic matter in soil has the benefit of sequestering greater atmospheric CO2and helping to combat climate change while also improving the ability of the soil to grow crops - an outcome she describes as a clear win-win.

As part of this research effort, Jones, Hannam and fellow UBC Okanagan soil scientist Andrew Midwood have been analyzing the chemical forms of CO2 that leave the soil surface during irrigation.

Working in a drip-irrigated apple orchard, the study involved continuous measurement of air coming from dynamic soil respiration chambers placed in the orchard. This allowed for high-frequency monitoring of the soil surface and air. The tests were repeated with different water supplies, using irrigation water or de-ionized water, and the results were remarkably different.

"It turns out that some of the CO2 released after irrigation comes from the natural salts--bicarbonates--dissolved in water from Okanagan Lake as it is applied to the soil," says Midwood. "It's a process we had not considered until we noticed some unusual results when we traced the source of the CO2."

Midwood is quick to point out that understanding the processes that drive the release of CO2 from the soil is essential in combatting rising atmospheric greenhouse gases.

"This is a natural process," says Hannam. "Our results have to be considered in a broader context. Irrigation is essential to fruit production in the Okanagan Valley. Along with causing the release of CO2, from bicarbonates in the water, irrigation is also promoting the removal of CO2 from the atmosphere by encouraging plant growth. It's a balance and to understand the balance, you need to know all the component parts."

Their research has practical applications for any agriculture-based community in any arid region, especially if the main source of irrigation is from an alkaline lake. As irrigation needs to expand across arid and semi-arid regions, CO2 emissions originating from irrigation water may climb.

Their work was funded by Agriculture and Agri-Food Canada's, Agricultural Greenhouse Gases Program and was recently published in Geoderma.
-end-


University of British Columbia Okanagan campus

Related Atmosphere Articles:

Physics: An ultrafast glimpse of the photochemistry of the atmosphere
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
Using lasers to visualize molecular mysteries in our atmosphere
Molecular interactions between gases and liquids underpin much of our lives, but difficulties in measuring gas-liquid collisions have so far prevented the fundamental exploration of these processes.
The atmosphere of a new ultra hot Jupiter is analyzed
The combination of observations made with the CARMENES spectrograph on the 3.5m telescope at Calar Alto Observatory (Almería), and the HARPS-N spectrograph on the National Galileo Telescope (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma) has enabled a team from the Instituto de Astrofísica de Canarias (IAC) and from the University of La Laguna (ULL) to reveal new details about this extrasolar planet, which has a surface temperature of around 2000 K.
An exoplanet loses its atmosphere in the form of a tail
A new study, led by scientists from the Instituto de Astrofísica de Canarias (IAC), reveals that the giant exoplanet WASP-69b carries a comet-like tail made up of helium particles escaping from its gravitational field propelled by the ultraviolet radiation of its star.
Iron and titanium in the atmosphere of an exoplanet
Exoplanets can orbit close to their host star. When the host star is much hotter than our sun, then the exoplanet becomes as hot as a star.
Astronomers find exoplanet atmosphere free of clouds
Scientists have detected an exoplanet atmosphere that is free of clouds, marking a pivotal breakthrough in the quest for greater understanding of the planets beyond our solar system.
Helium detected in exoplanet atmosphere for the first time
Astronomers have detected helium in the atmosphere of a planet that orbits a star far beyond our solar system for the very first time.
Mountain erosion may add CO2 to the atmosphere
Scientists have long known that steep mountain ranges can draw carbon dioxide (CO2) out of the atmosphere -- as erosion exposes new rock, it also starts a chemical reaction between minerals on hill slopes and CO2 in the air, 'weathering' the rock and using CO2 to produce carbonate minerals like calcite.
The changing chemistry of the Amazonian atmosphere
Researchers have been debating whether nitrogen oxides (NOx) can affect levels of OH radicals in a pristine atmosphere but quantifying that relationship has been difficult.
Hubble observes exoplanet atmosphere in more detail than ever before
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b.
More Atmosphere News and Atmosphere Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab