The Balance of Earth’s Carbon Cycles

Life requires balance. We spend a large part of our existence balancing our careers and our personal lives, our family and work obligations, and our own personal health. If something occurs that displaces one of the elements of our lives, we take action to bring it back into balance. The Earth is no different. Our planet uses carbon to regulate its temperature with three processes; the geological carbon cycle, the ice-albedo effect, and the biological carbon cycle.
Before Earth had life, two main processes worked together as a thermostat to keep the planet in equilibrium; the geological carbon cycle and the ice-albedo effect. The geological carbon cycle acts over millions of years, slowly pulling carbon dioxide (CO2) from the atmosphere into the Earth’s mantle and then releasing it back into the atmosphere. The process begins when CO2 in the atmosphere combines with water to create carbonic acid, a weak acid that rains down onto the land. Carbonic acid gradually eats away at rocks, breaking them down into various atoms that are missing electrons, known as ions. Rivers carry these ions into the ocean where they readily combine with carbon already present, creating limestone, which sinks to the bottom of the ocean. As plate tectonics slowly renews the Earth’s surface, the ocean floor is forced down into the Earth’s mantle and the calcium carbonate is melted down. Active volcanoes later release this material and the CO2 in it back into the atmosphere.
Where did the carbon in the shallow depths of the ocean originate? The ocean absorbs CO2 from the atmosphere using simple chemistry. When CO2 is dissolved in water, a hydrogen molecule is released. This hydrogen can react with some of the ions from chemical weathering to create bicarbonate molecules. The bicarbonate combines with calcium released during weathering to create calcium carbonate (i.e. limestone), which settles onto the ocean floor.
Artists impression of a snowball Earth. Source: <a href="http://www.geos.ed.ac.uk/homes/gstraath/project.html">http://www.geos.ed.ac.uk/homes/gstraath/project.html</a>

Artists impression of a snowball Earth. Source: http://www.geos.ed.ac.uk/homes/gstraath/project.html

A full turn of the geological carbon cycle happens on the order of a few million years. This process works in conjunction with the second ancient process, the ice-albedo cycle. Together, these two processes cause Earth’s temperature to oscillate between warm and cold periods. The ice-albedo cycle works much faster than the geological carbon cycle, on the order of tens of thousands of years. Like the geological carbon cycle, it is intimately tied to the Earth’s temperature. An object’s albedo defines how much sunlight it reflects, with a higher albedo meaning more reflection. Ice and clouds raise the albedo of a planet. If temperature decreases on Earth, causing the ice caps to grow, more of the Sun’s light is reflected back into space before entering the atmosphere. This means that the Earth’s ocean and land do not absorb as much solar radiation and cannot warm. This causes the Earth to cool further and increase the area the ice caps cover. Without the geological cycle to regulate this process, the Earth would be covered in ice.

As the polar ice caps grow, more and more of the water necessary for chemical weathering is frozen. This halts the chemical weathering process, causing CO2 to build up in the atmosphere and trap the sunlight that is not reflected back into space. As a result, Earth begins to warm, melting the ice caps and liberating more water to be used for chemical weathering.
Currently, volcanoes release up to 380 million metric tons of CO2 into the atmosphere per year. The amount of CO2 that is drawn out of the atmosphere due to chemical weathering depends on the rains but is not significant compared to the amount released and absorbed during the biological carbon cycle.
Occurring on time spans that match our own, the biological carbon cycle is fueled by plants. CO2 from the atmosphere is combined with water during photosynthesis to create sugars and oxygen. These sugars are then broken down for energy by living organisms and fires. After the sugars are broken down and used, the remaining molecules recombine with oxygen to recreate water and CO2. The CO2 then returns to the atmosphere, and the cycle starts anew. During this entire process, 120 Gigatons of CO2 is absorbed from and reemitted into the atmosphere. This is approximately 1000 times more than the amounts discussed during the geological carbon cycle, and it affects the global temperature on much shorter and more noticeable timescales.
Cartoon of Earth's Carbon Cycles. Courtesy of <em>Climate Placemat: Energy-Climate Nexus</em>, US Department of Energy Office of Science. (p.1)(<a href="http://www.berscience.org/posters/index.shtml" target="_blank">website</a>)

Cartoon of Earth’s Carbon Cycles. Courtesy of Climate Placemat: Energy-Climate Nexus, US Department of Energy Office of Science. (p.1)(website)

These are the carbon cycles that were in place on Earth before the industrial revolution. Humans have added an additional cycle to the planet. We contribute to the carbon levels in the atmosphere through emissions, when we burn harvested carbon deposits like coal and oil. Currently, human activity is emitting 9 Gigatons of CO2 per year into the atmosphere through fossil fuel burning. Our carbon footprint is between the geological and biological carbon cycles and the Earth is struggling to use up the additional CO2 that we’ve put there. This extra CO2 is being absorbed by the oceans, causing them to become more acidic. It is causing plant life to decrease the number of stomata they grow, so they do not intake more CO2 than is necessary. The added CO2 is causing the Earth to warm faster than any of the more ancient carbon cycles can cool it off. Humans are now a significant CO2 contributor to our planet. Just as we maintain balance in our own lives, we must take steps to ensure that our contributions do not throw a wrench in the carbon cycles already in place on our planet.


Peer edited by Suzan Ok & Holly Bullis

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This article was co-published on the TIBBS Bioscience Blog.

The Excellent Journey of Bob Bagnell

As I enter the Microscopy Services Laboratory (MSL), a soft southern accent greets me: “Come in- want a cucumber? Help yourself!”

Dr. Bob Bagnell, the faculty director of the MSL, is an institution at UNC. Over the course of thirty years, he has developed the MSL from a set of electron microscopes in the Pathology Department to a full-featured microscopy core, offering numerous light and electron microscopy services in the basement of the Brinkhous-Bullitt building. Bob is an expert at microscopy, a natural teacher who never hesitates to help his patrons whether they are newbies or experienced users. His good nature combines with acumen for troubleshooting in such a way that even if your slides are worthless, leaving the MSL in a bad mood is difficult. You know how to fix your experiment, and almost feel joy from your failure, because you learned from Bob. His frequent offers of fresh bread also help. Continue reading

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Traditionally, plant ecologists seeking to better understand plant communities looked up (at light availability or precipitation patterns), across the landscape (at elevation or topography), and down (at leaf litter depth or soil moisture). More recently, however, they’re starting to look below. Continue reading

The Quantum Mechanics Behind Biology

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Speaking of those subatomic structures, we’ve all heard that they exist and that they are the foundation of everything. However, these tiny, weird constituents of reality are often ignored on the everyday, macroscopic scale. Many scientists have assumed that once trillions of atoms come together to form an organism, such as a human, quantum effects are diluted. However, physicists such as Erwin Schrödinger (of Schrödinger’s cat fame), Niels Bohr, and Albert Einstein (to name a few) didn’t ignore the quantum realm, and as it turns out, neither should you. There’s substantial evidence that the weird, short-lived processes of quantum physics directly and meaningfully influence things on a physiological scale.

Here are 6 ways in which quantum mechanics potentially affects life on a physiological level:

1)   Photosynthesis works because of quantum coherence.

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The 2015 Ig Nobel Prize in Medicine: Kiss me for science!

This year’s Nobel Prizes in Medicine were awarded to William C. Campbell, Satoshi Ōmura, and Youyou Tu whose work to develop novel therapies for the treatment of globally devastating parasitic diseases such as River Blindness, Lymphatic Filariasis (Elephantiasis), and malaria. While this work was certainly important, the greatness of the awardees is already prominently displayed on the front page of the Cell website.

“I also hope that kissing will bring not only love, but also attenuation of allergic reaction.” ~Dr. Hajime Kimata

Less well known are this year’s Ig Nobel prize winners, which were awarded at the 25th First Annual Ig Nobel Prize Ceremony on September 17th, 2015. This year’s Ig Nobel Prize in Medicine was awarded to Hajime Kimata, as well as Jaroslava Durdiaková and colleagues Peter Celec, Natália Kamodyová, Tatiana Sedláčková, Gabriela Repiská, Barbara Sviežená, and Gabriel Minárik. The topic of their research? The health benefits of intense kissing (and other interpersonal activities). Continue reading

Blue Energy Research Underway in North Carolina

A new project kicked off this July as researchers across four institutions joined forces with local start-up companies, consultants, and coastal utilities to explore how a process that occurs naturally every minute along North Carolina’s coast may be harnessed for sustainable energy.

The process in question is the mixing of salt and fresh water in North Carolina’s sounds and estuaries. In order to develop technology and assess the feasibility of implementing such technology along North Carolina’s coast, researchers from North Carolina State University, the University of North Carolina at Chapel Hill, the Coastal Studies Institute, and East Carolina University are collaborating on a three-year project funded by the UNC Research Opportunities Initiative (ROI).

Co-principal investigator Orlando Coronell, PhD, Assistant Professor of Environmental Sciences and Engineering at the Gillings School of Public Health at UNC, describes the premise in terms of the more familiar process of desalinization. During electrodialysis Continue reading