Nav: Home

Colorado River's dead clams tell tales of carbon emission

October 28, 2016

Scientists have begun to account for the topsy-turvy carbon cycle of the Colorado River delta -- once a massive green estuary of grassland, marshes and cottonwood, now desiccated dead land.

"We've done a lot in the United States to alter water systems, to dam them. The river irrigates our crops and makes energy. What we really don't understand is how our poor water management is affecting other natural systems -- in this case, carbon cycling," said Cornell's Jansen Smith, a doctoral candidate in earth and atmospheric sciences.

Smith is lead author of "Fossil Clam Shells Reveal Unintended Carbon Cycling Consequences of Colorado River Management," published in the journal Royal Society Open Science, Sept. 28.

The new research, in collaboration with the University of Arizona and the Cornell-affiliated Paleontological Research Institution, provides a novel approach that combines biological and paleo methods to understand how a nearly dead river delta presents evidence of vast amounts of carbon being added to the atmosphere.

Smith said the river's tidal flats should teem with clams. But thanks to 15 dams on the main river and hundreds more on its tributaries, the 1,400-mile-long, once-mighty Colorado drips to a trickle before emptying into Mexico's Gulf of California. Based on estimates of washed-up clamshells that lived hundreds of years ago and the number of clams alive today, the researchers calculated the change of the river delta's annual carbon cycle.

"You used to step on clams with every step you took," he said. "Now, you don't."

While their shells are a natural carbon sink, living clams belch carbon dioxide as they breathe. A thriving delta can emit the carbon equivalent of about 15,000 cars annually, but the Colorado River's clams have died off, emitting less carbon dioxide. Said Smith: "It would be tempting to say, 'Look at this positive effect,' but it is not positive."

Large southwestern cities like Los Angeles, Phoenix, Tucson and Las Vegas draw the Colorado's water, while the carbon cost of transporting that water to cities and farms far outweighs the humble clam's own emissions.

For example, the Colorado River's waters cool the coal-fired Navajo Generating Station in Page, Arizona, a 2,250-megawatt power plant that supplies energy to California, Arizona and Nevada. The coal-fired electricity station emits the equivalent of 4.5 million cars annually -- one of the largest carbon dioxide emitters in the United States. Beyond the power plants, water is pumped from the river to places like Las Vegas to feed lavish water fountains or Arizona to water golf courses.

"The reduced carbon emissions at the delta -- resulting from diverted flow, conveying water to Southwestern cities - are vastly outweighed by the carbon emissions to divert that flow," said Smith. "We've supplanted a small, natural carbon emitter -- the clam -- with something far more detrimental to the atmosphere."
-end-
The study's authors include Daniel Auerbach, Office of Wetlands Protection and Restoration, U.S. Environmental Protection Agency; Alexander Flecker, ecology and evolutionary biology at Cornell; Karl W. Flessa, professor of geosciences, University of Arizona; and Gregory Dietl, Cornell adjunct assistant professor of earth and atmospheric sciences, and the Paleontological Research Institution, Ithaca. Cornell's College of Engineering funded Smith.

Cornell University

Related Carbon Emissions Articles:

Don't look to mature forests to soak up carbon dioxide emissions
Research published today in Nature suggests mature forests are limited in their ability to absorb 'extra' carbon as atmospheric carbon dioxide concentrations increase.
Global supply chains as a way to curb carbon emissions
The coronavirus outbreak raised everyone's awareness of the significance of global supply chains to modern economies.
Scrubbing carbon dioxide from smokestacks for cleaner industrial emissions
An international collaboration co-led by an Oregon State University chemistry researcher has uncovered a better way to scrub carbon dioxide from smokestack emissions, which could be a key to mitigating global climate change.
Global carbon emissions increase but rate has slowed
Global carbon emissions are set to grow more slowly in 2019, with a decline in coal burning offset by strong growth in natural gas and oil use worldwide -- according to new research.
Co-combustion of wood and oil-shale reduces carbon emissions
Utilization of fossil fuels, which represents an increasing environmental risk, can be made more environmentally friendly by adding wood -- as concluded based on the preliminary results of the year-long study carried out by thermal engineers of Tallinn University of Technology.
Arctic shifts to a carbon source due to winter soil emissions
A NASA-funded study suggests winter carbon emissions in the Arctic may be adding more carbon into the atmosphere each year than is taken up by Arctic vegetation, marking a stark reversal for a region that has captured and stored carbon for tens of thousands of years.
China's carbon emissions growth slows during new phase of economic development
Scientists from from the Academy of Mathematics and Systems Science, together with collaborators, recently revealed that China's annual carbon emissions growth declined significantly from 10% during the 2002-2012 period to 0.3% during the period from 2012-2017.
Study: Carbon emissions soar as tourism reaches new heights
A researcher at The University of Texas at San Antonio (UTSA) is examining how the flight routes people take to get to tourist destinations impact the amount of pollution in the air in a newly published study he coauthored in the Annals of Tourism Research.
Plants could remove six years of carbon dioxide emissions -- if we protect them
By analysing 138 experiments, researchers have mapped the potential of today's plants and trees to store extra carbon by the end of the century.
How buildings can cut 80% of their carbon emissions by 2050
Energy use in buildings -- from heating and cooling your home to keeping the lights on in the office -- is responsible for over one-third of all carbon dioxide (CO2) emissions in the United States.
More Carbon Emissions News and Carbon Emissions Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.