Cleaning Up Korea’s Air

By Matt A. Barr

Seoul, South Korea has a unique air quality problem. More often than not, a persistent haze colors its skies a dull gray and quickly crowds out the blue sky. Many highly industrialized cities experience these conditions, especially those whose economic progress developed too fast for environmental policy to keep up.

Air pollution is a serious problem not only in Seoul, but across much of the Korean Peninsula.

Efforts to bring emissions under control were implemented in 2005 by a Special Act of the South Korean government. In particular, PM₁₀, NO₂, and VOC emissions were targeted by the legislation with the goal of reducing them to ½ of the levels measured in 2001. This was to be accomplished by 2014, but observations and measurements of air pollution have deviated significantly from what many computer models predicted. While PM₁₀ concentrations are down, NO₂ and O₃ concentrations have gone up and consistently remain above prescribed levels, despite regulatory actions taken within the past decade. The question is why?

Enter EAS atmospheric chemist Dr. Greg Huey. This summer, Dr. Huey and his team of researchers traveled to Korea to help answer this question. For six weeks, he and his group flew several missions on NASA’s DC-8 airplane, an aircraft outfitted with a 25,000-lb payload of instruments used to monitor air pollutants at a variety of altitudes. The data they gathered, along with measurements from ground stations and satellites, will be used to get a better understanding of air pollution sources in the Seoul Metropolitan Area (SMA). In doing so, their data is expected to help characterize air pollution in new ways and potentially transform how air quality is monitored and improved for decades to come.

A look inside NASA’s DC-8 aircraft outfitted to carry a 25,000 lb science payload.

In conjunction with KORUS-AQ and other Korean government programs established to improve SMA’s air quality, NASA is developing a series of Geosynchronous satellites that will be capable of measuring air pollution with much greater resolution than what is possible with current satellites.  Right now, the orbits of satellites that monitor air quality pass over a specific region during a small window of time. This significantly limits their ability to obtain a full picture of how air pollution changes in that region. That window of time will broaden with the new generation of satellites, scheduled to be launched by 2020. The combination of data from the new satellites, ground station monitors, and in-flight observations is expected to reveal a clearer picture of Seoul’s pollution sources and perhaps answer questions about why environmental regulations have not led to the expected improvements in Seoul’s air quality.

Geosynchronous satellites orbit the earth at fixed locations. These satellites will provide a much clearer picture of pollution sources and distribution across Korea.

Two undergraduates, Maddi Frank and Maddie Nisi, accompanied Dr. Huey on his trip. They worked to help calibrate and maintain the instruments, two of which were mass spectrometers designed and built by Dr. Huey’s lab. These mass spectrometers sample air during the flights and analyze it in real time to measure a series of important pollutants. Some of the discoveries made during the flights contradicted widely-held assumptions about where much of the pollution was coming from. These findings have yet to be published, and they will remain so for our post here, but the take-away is that new scientific discoveries were unfolding before everyone’s eyes. For Maddi and Maddie, that brought a certain element of excitement to what was already the trip of a lifetime.

Maddi Frank and Maddie Nisi in their flight suits preparing for a flight in NASA’s DC-8 research plane. Photo courtesy of Maddi Frank.

Visit the EAS website and Dr. Greg Huey’s research page for more information!

Students in the Field Pt. 3

For this episode of Students in the Field, we spoke to undergraduate Riannon Colton about her experience on the research vessel R/V Falkor, operated by the Schmidt Ocean Institute. Riannon accompanied Dr. Annalisa Bracco to the South China Sea for research into the nutrient load being deposited by the Mekong River into the Sea. Take a look at Riannon’s blog to go deeper into her adventures at sea.

Researchers boarding the R/V Falkor from Nha Trang, Vietnam. Photo courtesy of Riannon Colton.

1.) What year are you?

I am a rising 3^rd year.

2.) What was the purpose of your research in Vietnam?

The purpose of the research is to study and measure nutrient fluxes from the Mekong River into the South China Sea. The Mekong River’s impact on the local ecosystem isn’t well understood at the moment, but it clearly plays an enormous role. Currently, there are plans to construct several dams along the length of the river which will change how the river’s nutrients are transported. Gathering data about nutrient fluxes now means that we can better understand the nature of those changes once the dams are in place.

3.) What was your specific role on the trip?

At the outset, my specific role on the trip was to assist with sample collecting and processing. I spent a lot of time collecting seawater from a CTD sensor – a sensor that collects data about the conductivity, temperature, and depth of the water in a particular location. However, after constantly asking everyone if they needed assistance on anything when I had nothing to do, I got assigned to the plankton net tows. I would complete the net tow with Andreas Lovotny, a Swedish Ph.D. student, and then he would show me the specimens we’d just collected under a microscope. I learned how to identify different phytoplankton thanks to his expertise.

At one point, I overheard one of the crew members talking about XBT’s, which caught my attention. I asked if I could learn how to launch one, and the answer was yes. XBT’s are another tool used to measure ocean temperature. These measurements are taken globally and, with several decades of data available, they provide a picture of the changing marine climate.

Whenever anyone needed help, I would assist them with their work, educating myself in all parts of the multidisciplinary ocean science team. Mónika Naranjo-Gonzalez, the ship’s journalist, decided to add to my list of things to do by giving me and another student small but fun tasks that taught us about communicating science to those who do not pursue science. From this experience, I was able to author of one of the cruise log entries on the Schmidt Ocean Institute website.

Riannon collecting seawater from the CTD Sensor aboard the R/V Falkor in June 2016. Photo courtesy of Riannon Colton.

4.) Did anything unexpected happen while you were on the trip? If so, how did you deal with it?

When I boarded the R/V Falkor, I really didn’t know what to expect. I knew very little about biology, let alone marine biology. During the first days of the expedition, I met Andreas and pretty much became his assistant, helping him collect and label samples from the CTD.

By the end of the trip, however, I’d also learned how to tie boating knots, steer a research vessel, put on fire safety suits as well as other protective gear, extinguish ship fires, communicate with other crew members over the radio, and how to correctly paint a ship. I was also given the task of recording salinity measurements as the ship sailed back and forth over the river plume boundary. The captain decided that I would steer the ship while others were recording the numbers too. Thankfully, I was able to personalize my research experience by participating in every aspect of the expedition.

5.) How did you come to be involved in Dr. Bracco’s research?

Dr. Bracco sent an email to all of the EAS students announcing an opportunity of a lifetime to which I responded with interest. There was a personal interview with Dr. Bracco and afterwards, she had was write 3-4 sentences on why we wanted the position.

6.) What would you say to any incoming freshmen or transfer students who might be considering whether or not to do research?

DO RESEARCH! Research is super fun, eye-opening, educational, makes you feel like a mad scientist, and presents wonderful opportunities of a lifetime.

Opportunities of a lifetime await the Georgia Tech Researcher. Riannon Colton aboard the R/V Falkor in the South China Sea, June 2016. Photo Courtesy of Riannon Colton.

7.) Do you have any plans for doing research with Dr. Bracco or other faculty for the remainder of your time at Tech?

I am currently working with aerospace professor Dr. Brian Gunter on the RANGE team in designing a CUBESAT satellite to accurately access planetary topography under a NASA grant.

I also plan to take any exciting arising opportunity in the research field. I absolutely love research!

Students in the Field: Part 2

After a short hiatus to enjoy the end of summer, we’re back with another installment of our Students in the Field series. This series follows EAS students who have participated in field work that enhances their research experience. In this entry, we interview undergraduate Sage Kemmerlin. Sage accompanied Dr. Andy Newman to Costa Rica this past spring and has been kind enough to share her story with us.

What year are you?

I am about to start my third/senior year.

What was the subject of your research in Costa Rica?

My research in particular is to try to determine the stability or lack thereof of the subsiding western flank of the volcano Arenal.

Getting excited about geophysics research at Arenal! Photo courtesy of Sage Kemmerlin.

What was your role on this trip?

My role was doing whatever Dr. Newman told me to do haha! We spent the first week of our trip in the Nicoya Peninsula, located on the Pacific coast of Costa Rica, to complete two main objectives. First, we set up GPS stations for a few days to begin acquiring data for 2016 – this helps Ph.D candidate Tiegan Hobbs with her research on post-seismic deformation in the Nicoya Peninsula. Second, we needed to perform maintenance on and update the memory cards of various seismic stations. Each day we would split up into groups to do these tasks. I found myself setting up and balancing antennas, setting up solar panels, setting up/taking down the GPS, or checking the seismic stations. It varied from day to day.

Placing GPS equipment and seismometers in Costa Rica. Photo courtesy of Sage Kemmerlin.

We spent the second week at Arenal, located in northern central Costa Rica. Our tasks there included carrying the 40-something-pound GPS units on our backs up the volcano to place them at specific locations. We also did some “reconnaissance” for Dr. Newman. He was curious about the existence of a fault in the area, which he identified as a possible research opportunity, so we drove around looking for ideal spots to place GPS pins. Once these pins were in place, we were able to set up the GPS to begin gathering data.

How did you come to start working with Dr. Newman?

I took the Earth Processes (EAS 2600) class with him in the fall of 2015. On the first day of class he described his research, which I thought sounded fascinating. Later in the semester I went to his office and asked if he had any research that I could help with, to which he replied that he did. He explained some options to me, and I decided that I wanted to work on the Arenal research.

Sage surveys the land at the base of Arenal in Costa Rica. Photo courtesy of Sage Kemmerlin.

Are you continuing any research with him related to your trip?

Yes, the research I did on the western flank stability at Arenal is ongoing. I worked on it this spring and will very likely continue to work on it this upcoming school year.

Did anything unexpected occur on your trip? If so, how did you deal with it?

Yes, there was one day when everything seemed to go wrong. There was this hill that nobody liked. Getting there required walking through a cow pen and climbing through plants that were covered with ants. If we touched the plants at all the ants would crawl onto us and bite our necks (thankfully no one had this happen to them.) Once we reached the top, we had to work in temperatures that hit 120º F. It was not a site that excited anybody. Several days prior to this particular day, we had set up a GPS unit on the top of this hill, which we then needed to retrieve later.

When we arrived to get this GPS, I didn’t think we were in the right place. It didn’t look right because there had been a fire on the hill – small wisps of smoke were still floating up from the ashes! We climbed the burnt hill to the top and our GPS was completely destroyed. The pelican box it was housed in was nothing but ash. All that was left was the melted batteries and the antenna, which had been knocked over. We deduced that the fire had been a controlled burn by the neighboring villagers, and that it had started at the bottom of the hill and worked its way to the top. It appeared that the fire heated the pelican box until it essentially exploded, causing the antenna to fall over.

The wrong place at the wrong time – remnants of GPS equipment after a controlled burn. Photo courtesy of Sage Kemmerlin.

We collected what we could of our melted gear and took it down. We later brought over another GPS and set it up there so that we would have GPS data for that station.

Would you say that doing research has enhanced your experience at Tech? If so, how?

Yes, definitely. It is really enjoyable to do something with real-world meanings attached to it. I feel like I am actually contributing (or at least attempting to contribute) to the knowledge we currently have. Understanding more about the subsiding flank on Arenal could lead to predictions about the potential for a landslide to occur. That information, in turn, could help save many lives.

Students in the Field

As you know, we have a variety of great research happening at EAS. Many graduate and undergraduate students are invited to participate in field work related to research and they return to campus with great stories. We’re going to start sharing some of those stories in their own words here.

Our first student is undergraduate Maddi Frank. Maddi accompanied Dr. Greg Huey on a fieldwork trip to Korea earlier this summer. Read on to find out more about her, her experiences there, and what advice she has for students who are coming into the EAS major this fall.

What year are you?

I am a rising 5th year/senior graduating in December 2016.

What was the purpose of your research in Korea?

Our mission was part of the KORUS-AQ (KOrea U.S. – Air Quality) program. KORUS-AQ is a field study with three main objectives. The first objective was to analyze the air quality and distribution of emissions both within South Korea and above the surrounding waters along the Asian Pacific Rim. This was achieved primarily with data gathered both from ground monitoring stations and several flights on a DC-8 aircraft repurposed by NASA to carry up to 25,000lbs of science instrumentation. The second objective was to analyze the locations, sources, and concentration of pollutants in air containing particularly heavy pollution loads. The hope is that this information and the models we can create with it result in a better understanding of how to focus our resources when tackling the pollution problem. Currently, the sources and mechanisms of air pollution transport through the atmosphere above Seoul remain something of a mystery. The third objective was to foster the relationship between the Korean and American governments, both of which share the goals of improving air quality and refining the technology used to study it. For example, previous measurements of air quality taken by LEO (Low Earth Orbit) satellites were low resolution and long in between each measurement – around once a day. To address this poor resolution, the development of a GEO (Geosynchronous Equatorial Orbit) satellite program is taking place thanks to resources contributed by the Koreans and the Americans. The first satellite is expected to be launched within the next few years. The hope is that greater engagement and cooperation between Korean and American science organizations would set the stage for future science collaboration, not only on air quality issues but in other fields of study as well.

Seoul, Korea as seen on a day with relatively low air pollution. Taken from NASA’s DC-8 aircraft used to fly missions for KORUS-AQ, a joint Korean-American program intended to study air quality in the Seoul Metro Area. Photo courtesy of Maddi Frank.

Seoul, Korea as seen on a day experiencing high levels of air pollution. This picture and the previous picture were taken in the same area, illustrating the severity with which air pollution can affect the city. Photo courtesy of Maddi Frank.

During the flight, much the data we collected was presented on a monitor. This monitor essentially displayed our data in real time, which allowed us to communicate with the other scientists on board when we flew through areas with high concentrations of sulfur dioxide or PAN (both toxic substances in the air). The structure of the project was quite multifaceted in this way. There was so much coordination between the teams involved with ground/in-situ measurements, satellite, geostationary satellite observations, modeling – it was incredible to see! The NASA KORUS-AQ white paper linked here goes into more detail about what kinds of scientists were involved and the science questions we were attempting to answer with this project.

What was your specific role on the project?

Most of our work took place on the research aircraft and my specific role onboard was to help support the construction of the instruments (or to adapt preexisting instruments for the purposes of this mission). The instrument our group built and operated is called a CIMS (Chemical Ionization Mass Spectrometer). It works by capturing ambient air from outside the aircraft and directing it through a space where it can be analyzed. Once inside the CIMS, the particular species of pollutant that we were trying to measure was ionized by a reagent ion through a chemical reaction. From there, the mass spectrometer detected the gas in question because molecules of the ionized gas will follow a certain path, so to speak, based on their individual masses.

The Georgia Tech CIMS machine used on the KORUS-AQ mission. A Chemical Ionization Mass Spectrometer designed and built at Dr. Greg Huey’s lab used to analyze different gases present in the air in and around Seoul. Photo courtesy of Maddi Frank.

It was also my job to help with the maintenance of the instruments, which included calibrating the different flows associated with each instrument (inlet flows, calibration gas flows, etc.) This was important because we would need to take into account any calibrations that did not appear as a linear correlation with corresponding voltage values. Failing to do this would greatly disrupt the processing of our data. I also helped change out any gas cylinders needed for operation (those things are heavy!) and other general maintenance.

During the flights, which usually lasted eight or nine hours, Dr. Huey and GT Research Technologist Dave Tanner would teach us about the chemical mechanisms at play and any implications of the spikes in the gases we were measuring. This provided so much valuable knowledge that I would not have been able to get otherwise. I also helped document any changes made to the instruments or any issues that we faced.

Did anything unexpected happen while you were there? If so, how did you deal with it?

Flying on the aircraft wasn’t always so pleasant. We flew very low (500ft above water or 1000ft above land) for extended periods of time, which made the cabin in the aircraft very hot. Also, flying so low means flying in/through the Boundary Layer, which is often very bumpy. Korea’s terrain is quite rugged as well, which made flying even bumpier than normal at times. But it was always cool to go hang out in the cockpit with the pilots or roam around the airplane to see the other instruments operating and collecting data. It was also very interesting to see the science in real time, meaning that the instruments that WE built were working and we could see the chemistry happening right before our eyes!

Maddi Frank and Maddie Nisi in their flight suits preparing for a flight on NASA’s DC-8 research plane in Seoul, Korea. Photo courtesy of Maddi Frank.

I was also surprised at just how poor the air quality was there! The difference in visibility between days with high pollution vs those with low pollution was shocking! I also physically felt the effects of being there and breathing in all the polluted air. I noticed after a few days that my throat would hurt in the morning, and I even had a slight cough and congestion! Being there for an entire month, I feel like I eventually acclimated, but still! The people who live and work there have to breathe all that in everyday!

Did you have any down time to explore the area you stayed in?

I did have time to explore actually! We usually had one hard down day per week. My friend and co-worker Madison (Maddie) Nisi (yes, we were known as the Maddi(e)s with the people we worked with) and I took advantage of these days to go explore Seoul, go hiking, and travel down to Busan (a beach city on the southeastern part of the peninsula). We quickly mastered the amazing public transportation there. We would wander around Seoul to take in the life and culture there. It was awesome! We had many people point us in the right direction when we looked lost, and they were always willing to recommend places that we should go! On one of our days off, we went to a palace called Gyeongbokgung. It was beautiful, and so big! We wandered around there for an entire day, making sure we went through every door. We also saw live traditional music and dancing there, which was interesting.

On another day off, we went hiking just outside of Seoul. It was funny because if you went hiking here in Atlanta, you’d have to drive an hour or so out of the city. But there, the subway takes you almost right to the trailhead. It was a very rocky hike, but with beautiful views of Seoul!

Hiking outside of Seoul during a day off. Photo courtesy of Maddi Frank.

We were also staying on Osan Air Base, which is an American air force base in Pyeongtaek, South Korea, and we were able to explore around there. Just off base was a small town called Songtan which had a ton of fun restaurants, vendors, shops, bars, etc! We would frequently venture out there for dinner. We even made friends with some of the airmen and airwomen who were stationed at Osan AB! We spent a lot of time with other scientists who were participating on the mission as well and got to hear funny stories about past missions they had been on together.

How did you come to be involved in Dr. Huey’s research in Korea?

I’ve been working for Dr. Huey in his lab for 2 years. This is the 2nd science field mission I have done with him as part of the lab. The first was when the lab was funded for a project called FRAPPE (Front Range Air Pollution and Photochemistry Experiment) out in Colorado. I got to spend my summer out there, and that was my first science field mission project! But that was on the C-130 aircraft, which is not nearly as smooth or as nice as the DC-8. When we got funded for the KORUS-AQ project, he asked if I wanted to go out to Korea for some time and help out, and, of course, I said yes! I got to work closely with him and Dave Tanner while I was out there, and learned so much from them.

Do you have any advice for incoming freshmen/transfer students?

Absolutely! First, it’s okay if you don’t know what you want to do right away. Even if you think you do, always keep an open mind! You are in school (a widely esteemed school at that) to learn and see what’s out there for you! I thought I wanted to be an aerospace engineer for almost my whole life. When I got involved in the curriculum, however, I saw that it wasn’t for me. I decided to switch my major to EAS (meteorology) with the hopes of entering the aviation/aviation meteorology field. There is more than one path to get where you want to go.

Second, absolutely get involved with research!!!! The department you’re in doesn’t matter, research is always available. There are so many benefits! You get to work closely with awesome faculty/staff and build a relationship with them that could be very useful to you later on! They can potentially become your professor or advisor, and even provide you with recommendation letters or connections when it’s time to apply for jobs or grad school!

Research is also great because you can receive course credit or a paycheck. You also get a hands-on learning and work experience that you wouldn’t otherwise get. Having that experience allows you to see if it’s something you may want to pursue further in your academic or post-academic career. You might also get to travel and do research in a foreign country one summer while getting paid!

Third, get involved with your research early. Professors are more than willing to take freshmen and sophomores/transfers. I hadn’t even taken a single EAS class when I started doing research with Dr. Huey. Research in other departments is also a possibility. There are always collaborations between departments going on. It’s as easy as emailing a professor whose research interests you and asking to meet with them about it. I promise it will enrich your learning experience and time here at GT.

That said, I also recommend getting involved with anything else you may be interested in early on so you have time to enjoy it! It’s okay to take less than 18 credit hours if you cannot handle it. You are smart, that is why you are here, but make sure to put yourself first and put yourself in a position to succeed while still staying healthy and enjoying the college experience.

Finally, make friends in your major! EAS is lucky because we have a small student body; we’re all friends. We are willing to help each other or always study together. Regardless, try to find at least ONE person in each class you take with whom you can study and work through homework problems.

A Captured Earthquake

By Matt A. Barr

At 8:42 am local time on September 5, 2012, a magnitude 7.6 earthquake struck the Nicoya peninsula on Costa Rica’s west coast. The ground shook as far away as Nicaragua, El Salvador, and Panama, with the eruption of Nicaragua’s largest volcano resulting three days later. Tsunami warning systems were triggered along the region’s Pacific coastline, a stark reminder that earthquakes in fault zones like this one also awaken the oceans. It would take several months and millions of dollars before the region recovered.

Dr. Andrew Newman saw it coming.

Centered on the Nicoya Peninsula on Costa Rica’s Pacific coast, a magnitude 7.6 earthquake struck on September 5, 2012. This came only two months after a report by Dr. Newman’s research group detailing the likelihood of such an event.

Dr. Newman regularly travels with students between his office at Georgia Tech’s School of Earth and Atmospheric Sciences and Nicoya, Costa Rica to work with a team of international scientists studying the fault there.

Seismometers located at strategic points throughout the region measure the energy released by almost any tectonic motion in this subduction zone, while GPS equipment plots the corresponding movement of land. Using records dating back to the 19^th century and observations recorded by their instruments, careful analysis using geometric maps of the fault and precise deformation models has been conducted by Dr. Newman and his colleagues. This analysis gave them astounding insight into the tectonic activity in Nicoya and allowed them to forecast with reasonable accuracy the maximum likely magnitude and location of the next big quake. Timing, however, is difficult to pin down in earthquake science. With the team settling on a recurrence interval of about 50 years, and the last magnitude 7.0+ earthquake to hit the region occurring in 1950, another event was overdue as of 2012.

Dr. Newman checks GPS equipment during a fieldwork excursion to Costa Rica.

In almost every subduction zone, the most seismically active part of the fault lies far offshore. These faults, known as subduction megathrusts, are typically the largest faults on Earth. Consequently, they produce the most powerful earthquakes (the tsunami that caused the Fukushima disaster in 2011 resulted from a magnitude 9.0 earthquake that occurred at a subduction megathrust zone.) The “Ring of Fire” around the Pacific Ocean indicates the locations of many of these faults, which are created when tectonic plates collide and one subducts beneath another. When this subduction occurs, the top plate is pushed upward, often creating habitable land, while the bottom plate founders into the earth’s mantle. The volcanic activity characteristic to the Ring of Fire is due in part to the melting crust of the lower plate that results from the plate’s insertion into the hotter mantle. This interaction between plates also creates a deep trench where the beginning of associated subduction zones can be found.

Subduction zones indicate locations where two tectonic plates are converging. One plate is pushed upward while the other sinks into the earth’s mantle. This interaction can lead to powerful earthquakes and volcanic eruptions.

The Nicoya subduction zone is unique in that the active megathrust fault is located directly beneath land rather than offshore. This allows for land-based seismic and GPS equipment to be deployed as opposed to ocean-based instruments, which can be cost-prohibitive and imprecise. These instruments allowed Dr. Newman and his team to conclude that the likelihood was high for an earthquake possibly reaching magnitude 7.8 to strike the Nicoya subduction megathrust zone. Their findings were published in July of 2012, just two months before the magnitude 7.6 earthquake struck the region on September 5^th. It was later determined by Newman’s team that the size of the locked portion of the fault – the portion where the earthquake’s energy is stored – was slightly smaller than what their data showed prior to the earthquake. This is a possible cause for the 0.2 difference in their forecast. Monitoring of the region is ongoing.

The wealth of knowledge stemming from Dr. Newman’s research is one reason that he advocates for more resources being spent on developing better ocean-based earthquake monitoring technology. If it’s possible to forecast an earthquake like the one that struck Nicoya on September 5^th for “little more than the cost of gas to get out there,” according to Dr. Newman, it stands to reason that similarly precise forecasting could be achieved for offshore subduction zones with the properly allocated resources.

This model shows how current seismology research in the ocean is conducted. This research is often cost-prohibitive and unreliable, however. Dr. Newman works to address funding and technological obstacles that prevent better understanding of these earthquake zones.

More recently, Dr. Newman has been studying the Arenal volcano located in Costa Rica’s Guanacaste Province. Arenal is experiencing considerable subsidence on its western flank as the result of a 1968 eruption. This subsidence is alarming not only because of its potential to trigger landslides, but a rapid de-pressurization of volcanic magma chambers due to flank collapse may lead to a substantial and surprising eruption.

Arenal volcano towers over Lake Arenal in Guanacaste, Costa Rica. Dr. Newman and his research team are assessing the possibility of its western flank collapsing. Multiple villages and a large hydroelectric dam could be threatened if Arenal erupts due to this collapse, a fate similar to that witnessed on Mt. St. Helens in 1980.

A flank collapse occurred under similar conditions at Mt. St. Helens in 1980, entering the history books as the largest landslide ever recorded and leading to the eruption there. It remains to be seen whether the subsidence at Arenal is stabilizing or destabilizing its western flank, but should the latter be the case, neighboring villages along with one of Costa Rica’s most productive hydroelectric dams could be destroyed.

Special thanks to undergraduate Sage Kemmerlin for her contribution to this article. She accompanied Dr. Newman to the Arenal volcano in Costa Rica this past spring to assist in his research there.

Check out Dr. Newman’s research page for more information, along with our EAS page to learn about other exciting research happening at Georgia Tech!

The Phosphorus Man Cometh

By Matt A. Barr

Think of all your favorite fireworks, fertilizers, detergents, and sewage pits. Got them all in your head? Great. Now think of all your favorite bones, teeth, DNA, RNA, and cell membranes. Finally, think of all your favorite plants and algal blooms. What do these things have in common? Phosphorus, of course. This versatile element is critical to all life, and here at the School of Earth and Atmospheric Sciences, it is taken very seriously by Dr. Ellery Ingall and his team of researchers.

Due to its high reactivity (it explodes upon contact with air), phosphorus does not occur naturally as a free element on Earth. Instead, it’s most prevalent in mineral form as phosphates – one phosphorus atom with four oxygen atoms attached. These phosphates are mined and refined for use in agriculture and industry. One of the most common destinations for refined phosphate is fertilizers. While these fertilizers do serve a purpose in large-scale farming activities, they can ultimately end up in waterways and lead to algal blooms that threaten the health of freshwater and certain saltwater environments. Phosphates can also compose aerosol particles that are transported through the atmosphere and deposited in ecosystems that may be incapable of supporting excess phosphorus.

Phosphorus is an essential nutrient to aquatic life. Too much phosphorus can spur growth beyond what a body of water can support, however. When this happens, algal blooms can starve other life of oxygen and cause significant die-offs of neighboring species. Here, an algae bloom indicates signs of eutrophication, Danube old arm, Szigetkozi Nature Reserve.

Phosphates form the backbone structures for DNA and RNA though, and phosphorus, separated from its mineral structures by organic metabolic processes, acts as a limiting nutrient in many terrestrial and marine ecosystems. This latter role makes the availability of phosphates to organisms a significant factor in determining any growth in those ecosystems.

Phosphorus only occurs naturally on Earth as mineral compounds with other elements. Phosphorus is in its most stable form as phosphate.

The Eastern Mediterranean Sea is one such ecosystem that Dr. Ingall and his research team consisting of Amelia Longo, Julia Diaz, Michelle Oakes, and Laura King have focused on due to dust plumes that are deposited there from continental Europe and Northern Africa. The winds over Europe and North Africa gather up the dust and other aerosols containing phosphates and transport them to the Eastern Mediterranean. In a region such as this where phosphorus content would otherwise be relatively scant, it’s easier to observe what effects result from increased phosphorus deposition.

Dr. Ingall and his research team analyzed samples from the Eastern Mediterranean to determine the phosphorus sources leading to increased aquatic growth in the region.

Specifically, phosphorus in aerosols – the microscopic particles that compose the dust plumes – is the subject of the Ingall Lab’s research. He and his team use a synchrotron located at Argonne National Laboratory to identify the composition, mineralogy, and solubility of different phosphorus species present in aerosols from the dust plumes. The synchrotron is a particle accelerator that exposes the aerosol particles to high energy X-rays. Using these X-ray measurements, Dr. Ingall can characterize an entire plume with the information derived from a few small samples. Amelia Longo led the effort to understand these plumes. It was determined that phosphorus compounds from the European sources were much more soluble in water and, therefore, impacted growth in the eastern Mediterranean to a greater extent than those from North African sources. This came as something of surprise because previous studies and years of satellite data showed that higher quantities of phosphorus were being deposited by the North African plumes. While it was true that more phosphorus was coming from the North African plumes, this phosphorus was much less soluble than what was present in the European plumes, meaning relatively little of the North African phosphorus was affecting the growth of aquatic organisms in the region. Furthermore, the more soluble European aerosol phosphorus was organic in nature and appeared to originate from bacterial sources, whereas the less soluble North African phosphorus was locked up in minerals and lacked organic components.

Dr. Ingall’s students help collect samples to be analyzed for phosphorus content.

Using the synchrotron, Dr. Ingall and his team have analyzed a variety of sample mediums for elements other than phosphorus as well. Before applying this technique to the study of phosphorus, Dr. Ingall was involved in researching iron, another limiting nutrient in the oceans. Taking samples from sites across the world and studying them with the help of the synchrotron, Dr. Ingall has identified how iron is used by diatoms whose activities greatly affect the availability of iron for other marine organisms. In Antarctica, these diatoms – microscopic unicellular organisms – appear to be storing iron in the silicate shells they develop as a barrier between themselves and the water. The exact purpose for this is unknown because, according to what Dr. Ingall and his team have observed, the iron stored in their shells is more than what the diatoms require for typical metabolic activities. Research into this question is still ongoing and has been primarily the work of Amelia Longo, who just completed her Ph.D. and Julia Diaz, one of Dr. Ingall’s former grad students, who is now an assistant professor at the Skidaway Institute of Oceanography in Savannah, Georgia.

The synchrotron, a particle accelrator used by Dr. Ingall and his researchers, assists scientists across a variety of disciplines. It is housed at Argonne National Laboratory outside of Chicago, IL.

Along with his studies of phosphorus and other elements in aerosols, Dr. Ingall is in the process of developing new research into the composition of urban aerosols. In conjunction with Dr. Rodney Weber, an atmospheric chemist here at EAS, Dr. Ingall hopes to use the power of the synchrotron to analyze aerosol samples taken from right here in Atlanta. Characterizing the components of these aerosols can go a long way towards understanding the health risks associated with increased human exposure to toxic metals present in aerosol pollution. It may also shed light on some of the lesser-known atmospheric processes that cause the reduction of those metals. This reduction – an exchange of electrons between two species – typically results in these metals having higher solubility, making them more susceptible to dissolving in waters that ultimately end up in our water supply.

As always, be sure to check out our EAS website and Dr. Ingall’s page for more information.

 

A changing river: Measuring nutrients fluxes to the South China Sea

Below is a fascinating insight into GT EAS oceanography research, in conjunction with the School of Biology, that’s happening right now in the South China Sea. Many thanks to Dr. Bracco and undergrad Riannon Colton for sharing their experiences with us! We will be posting updates from their research here regularly. Be sure to take a look at Riannon’s blog to read all about the life of an oceanography researcher at sea!

Credit: Dr. Annalisa Bracco

Why Vietnam?

Anthropogenic pressures are threatening Vietnam’s coastal waters despite their vital role in the regional and national economy. Policies and developments in the next ten years will determine the chances to preserve both the Mekong Delta – that is subsiding at an alarming rate – and Vietnam’s relatively pristine coastal ocean. The socio-economical impacts of maintaining current practices in light of the challenges ahead would affect millions of people.

The Mekong River is a critically important resource for millions of people living in Southeast Asia. Its delta and the waters it delivers to the South China Sea are vital to the coastal communities that depend on it.

A few facts

The Mekong Delta is largely used for agricultural production (mostly rice), but aquaculture has been rapidly increasing at the expense of mangrove and hardwood forests. Those and other land use changes are contributing to increased nutrient loading to the Mekong River waters and in turn to the Vietnamese portion of the South China Sea, promoting coastal and offshore eutrophication.

In the near future, additional and larger anthropogenic forcings will profoundly alter the linkages between the Mekong system and the South China Sea, which supplies a critical part of Vietnam’s seafood needs.  Recent and planned construction of dams and reservoirs in the Mekong Basin will fundamentally change the discharges of water, sediment, and nutrients to the ocean. By 2030, the construction of 11 new reservoirs in the lower Mekong basin, together with 62 hydropower dams distributed along the Mekong and its major tributaries in both China and Vietnam will reduce the mean seasonal flow cycle (by up to an order of magnitude) and sediment loading (up to 80%) of the Mekong River.  The diminished freshwater and sediment input will sharply reduce nutrient supply and modify nutrient cycling, altering the biogeochemistry and circulation of the whole basin in ways as yet unexplored.

At this time there are no studies or initiatives to evaluate the connections between regional policy decisions and the future of the South China Sea marine ecosystem. There are limited capacity building initiatives to train marine scientists on the trans-disciplinary research that is so urgently needed to address this major ocean threat.

Our contribution so far

Dr. Joseph Montoya (School of Biology) and Dr. Annalisa Bracco (EAS) have the extraordinary opportunity to conduct two research cruises on the R/V Falkor to the South China Sea, one ongoing and a second one in September of this year through funding –in the form of ship time – from the Schmidt Ocean Institute. Joining them are Riannon Colton (EAS undergrad), Caroline Reddy (Biology, technician) and Ana Clavere Graciette (Biology, postdoc).

Scientists boarding the R/V Falkor for the first time in Nha Trang, Vietnam on June 1st 2016. They departed Nha Trang June 3rd and arrived to the first station on the 4th in the early morning. (courtesy of Riannon Colton)

The goal of these research cruises is to provide a critical baseline for understanding the impacts of the changes under way in the river delta and adjacent ocean waters by characterizing physical and biogeochemical conditions of the coastal waters affected by the Mekong River plume through a broad survey during the critical Southwest Monsoon season (June to September).

It is the first effort of this sort on a US research vessel in the past 30 years.

Scientists from Columbia University and the Leibniz-Institute für Ostseeforschung in Rostock, Germany join us, together with Vietnamese colleagues at the Institute of Oceanography in Nha Trang and at the Ho Chi Minh City University of Science.

The Vietnamese coastal waters are particularly rich in fish during the summer season. This is due to the elevated concentrations of nutrients (nitrogen, phosphorous, silica, iron…) within the surface ocean layer where photosynthesis can take place. High chlorophyll levels then cause zooplankton blooms that in turn attract predators (fish) and fishing vessels. Those nutrients are supplied to the upper water column where they are consumed by phytoplankton, through wind-driven upwelling (the seasonal monsoonal winds tend to push the water along the coast towards the north, bringing more water from underneath at the surface) and/or by the Mekong River, whose waters are particularly rich in nitrogen and phosphorous collected while streaming across China and Vietnam.

Today we are sampling our second station, near the Vietnam coast and within the coastal area impacted by wind-driven upwelling. Further south elevated concentrations of chlorophyll are linked less to upwelling and more to the abundance of nutrients associated with the Mekong River outflow.

Satellite images of SST (sea surface temperature) (left) and chlorophyll (right) on June 4, 2016. Colder SST are associated to wind-driven upwelling, while elevated chlorophyll levels can be seen in upwelling areas and in waters modified by the Mekong River plume. Stations covered so far are indicated in both images by white dots. (Courtesy of Ajit Subramaniam)

Fishermen worried that we could be cutting through their lines on June 5th, 2016 at our second station. (A. Bracco)

Keep checking in to follow along as our students and faculty continue on this important mission to understand how the Mekong River Delta may be changing in the very near future.

That’s No Moon…

By Matt A. Barr

The prospect of life existing on other worlds has manifested itself in human culture for millennia.  In a way, aliens have been visiting us ever since we could communicate.  They’ve been the subject of our stories, our works of art, and even our religions, conjuring vivid worlds and exotic forms limited only by the imaginations of those who entertain them.  Science fiction is often the realm of the alien, but very much embedded in fact is the potential to find alien life right here in our own solar system.

As discussed in previous posts, the conditions under which life as we know it may exist must include the presence of liquid water.  Microbial life stretches our definitions of those conditions, and microbes are what we’re likely to find if we do discover alien life.  With the recent discovery of flowing water on Mars, as well as our increasing understanding of microbiology, finding life on other worlds seems to be simply a matter of time.  Luckily, we know what microbial life looks like here on Earth, and we know what conditions it can thrive in, meaning we can minimize that time by pointing our sights toward the stars to find where else those conditions might exist.

It turns out, they exist on Europa.

If there’s life anywhere else in our solar system, it’s probably on Europa.  Europa is a mysterious icy moon orbiting Jupiter that has gripped the curiosity of planetary scientists for several decades.  First discovered by Galileo in 1610, it would be more than four centuries before anyone turned their attention to the secrets it may hold.

While telescopes have been trained on Europa for some time, NASA’s Galileo mission in the late 1990’s produced some tantalizing data about the moon.  Europa appears to be the most active planetary body in our solar system besides Earth.  It’s estimated that roughly 100-150 km of an outer shell consisting of ice and a subsurface ocean completely encircle Europa’s silicate crust, and the interaction between these three features on Europa is of great interest to the scientific community.

Europa – one of Jupiter’s four Galilean Moons. Its surface offers an exciting prospect for hosting alien life.

Dr. Britney Schmidt, a planetary scientist at the Georgia Tech School of Earth and Atmospheric Sciences, and her research team, consisting of graduates Heather Chilton and Jacob Buffo, and undergraduate Josh Hedgepeth, are fascinated by the potential to harbor life that Europa holds.  Understanding Europa’s planetary processes is critical to answering its habitability questions though.  By conducting important research at ice shelves in Antarctica, specifically at the areas where ocean and ice directly interact with one another, Dr. Schmidt and her team hope to develop a working analog to what’s happening at the same types of physical boundaries on Europa.  Doing so would go a long way towards answering some of those questions.

At Antarctica’s McMurdo Ice Shelf, Dr. Schmidt and scientists from several other universities collaborate to gather data about the ice by sending robotic probes into the water below.  As part of a project known as SIMPLE (Sub-Ice Marine and PLanetary-analog Ecosytems), funded by NASA’s Astrobiology Science and Technology for Exploring Planets program, multiple expeditions scheduled over several “seasons” offer extraordinary opportunities to deploy up to five different submersibles into these frigid, unexplored waters.  These submersibles are used to collect samples, make observations about the water column, and seek to determine what processes govern the highly dynamic relationship between the surface of the ocean and the bottom layer of the ice shelf.  One of these submersibles, the Icefin, was designed and built by Dr. Schmidt’s startup here at Georgia Tech, and is slated for new upgrades between now and the upcoming Antarctic field expeditions.  These upgrades will allow the Icefin to operate in much wider areas than are currently possible to explore.

One of the submersibles used to explore the waters beneath Antarctica’s McMurdo Ice Shelf.

We know that the Antarctic ice shelves can serve as analogs for Europa’s ice shell, but is there anything about Europa besides its liquid water that indicates the possible presence of life?  It’s not so much that liquid water exists on Europa as it is the reasons why the water is there in the first place.  Scarred with massive crevasses and chasms, Europa’s icy surface tells the story of significant geologic activity below.  One hypothesis for the source of this geologic activity is that Jupiter’s gravity is pushing and pulling on Europa, depending on the relative position of one to the other.  This is similar to the Earth-moon gravitational relationship we experience here, except that rather than merely changing the tides, Jupiter causes Europa’s interior to flex such that the resulting friction is likely causing Europa to heat up.  This thermal energy is robust enough to maintain liquid water above Europa’s crust.  Being outside of the habitable zone, however, Europa’s liquid water freezes over at a specific, as yet unknown depth to form the ice shell we observe.

This heating of Europa’s interior seems to result in the geologic activity that transports non-ice material from Europa’s crust toward its surface.  This material is visible to us in the form of dark reddish-brown areas scattered all across Europa’s surface, and it’s these areas that are the most likely candidates for hosting the first alien life we could encounter, to say nothing of what might exist in the ocean itself.  Similar non-ice material – material that happens to support life – is consistently observed in ice shelves on our planet.  The ocean-ice-continent interaction occurring beneath these ice shelves, powered by the earth’s geologic activity, deposits this material into the ice via convection processes.  The thinking goes that if we can understand how that’s happening on Earth, we will understand how it might be happening on Europa also.

An ice shelf in Antarctica changes colors at locations where non-ice material is transported to its surface from the waters below. These areas are teeming with microbial life. Is something similar happening on Europa’s surface?

As it happens, habitability questions are also climate science questions.  Dr. Schmidt’s research ends up serving another purpose aside from understanding how alien life might develop on ice moons.  Her team’s submersibles are looking at how the oceans change the ice shelves and vice-versa, which addresses some particularly crucial gaps in our knowledge of the mechanics governing how climate change affects our Polar Regions.  Killing two birds with one stone is something we like to do here at Georgia Tech.

Understanding how the ice, ocean, and continental shelf interact at crucial ice shelf locations helps Dr. Britney Schmidt and her team answer questions about both climate science and planetary habitability.

A final note of congratulations is in order.  Dr. Schmidt has recently been appointed to the science definition team for NASA’s Large UV/Optical/Near-Infrared (LUVOIR) telescope project.  She also has a few other exciting announcements whose releases we don’t wish to precede here, but she’s representing Georgia Tech and EAS in some pretty great ways.  Check out EAS in the coming days and weeks for the details.

Update: We’re proud to announce that Dr. Britney Schmidt has been selected to join the board of directors for The Planetary Society.  For more info about this appointment, see the Georgia Tech College of Sciences story.

Planetary Society CEO Bill Nye pins Dr. Britney Schmidt with the Planetary Society logo pin following her appointment to the board of directors.

Unlocking the Mysteries of the Microbes

By Dr. Jennifer Glass and Matt Barr

Now that we’ve laid a foundation for microbial activity early in Earth’s history, we will start discussing some of the exciting research going on at Georgia Tech in the School of Earth and Atmospheric Sciences (EAS).

For over three-fourths of Earth’s history, its ocean chemistry was vastly different than it is today. Instead of today’s “anemic” (iron-starved) oceans, the ancient oceans were “ferruginous”, containing low oxygen and abundant iron. By studying modern ecosystems that still retain ferruginous habitats, “geobiologists” at GT EAS and around the world are probing questions about how microbial life flourished and changed the face of the early Earth.

Dr. Jennifer Glass’ research group is at the forefront of studying interactions between microbes, iron and greenhouse gases. In addition to carbon dioxide, two other important greenhouse gases are methane and nitrous oxide, both of which likely warmed our planet enough to enable the persistence of liquid water and evolution of early life billions of years ago, despite the faint young sun paradox discussed in our previous post.

The Glass lab is studying greenhouse gas cycling via microbial and abiotic redox reactions, which move electrons between chemicals towards a state of lower free energy, and are crucial for all life. These redox reactions are also key to nutrient cycles that move bioessential elements like carbon, nitrogen and iron through planetary ecosystems. Half the lab works on methane, and the other half on nitrous oxide, with iron as a common theme connecting the two.

Methane is the second most abundant greenhouse gas on modern Earth and may have been even more important in our planet’s past. With funding from NASA’s Exobiology and Evolutionary Biology Program, the Glass lab and its collaborators are testing the hypothesis that iron and methane contributed to early metabolic processes of primitive – yet completely unknown – microbes that likely still exist today in ferruginous ecosystems. These microbes might “breathe” iron and “eat” methane to obtain energy and food.

Lake Matano in Indonesia is one of the best analogs that exists today of ferruginous oceans that existed in the Archean Eon. While most lakes turn over at least once a year, Lake Matano’s deep waters are too dense to mix with its surface waters. This means that the mud at the bottom of Lake Matano is completely shielded from atmospheric oxygen and is constantly bathed with iron from mineral-rich soils flanking the lake. Consequently, it may harbor microbial communities similar to those in the Archean oceans. Collaborator Dr. Sean Crowe of the University of British Columbia, an adjunct professor in EAS, has provided the Glass lab with sediment samples from a variety of depths in this ecosystem.

Lake Matano lies on the Indonesian island of Sulawesi. Its waters are uniquely characteristic of the Archaean oceans that are key to unlocking the secrets of early life on Earth.

Glass lab PhD candidate Marcus Bray and postdoc Dr. Nadia Szeinbaum are cultivating microbes from these precious sediments to decipher how their ancient relatives were able to grow without oxygen in Earth’s deep past. They exposed these microbes to metal-rich minerals and methane and then waited patiently while both substrates were slowly transformed. They’ve also teamed up with the lab of Dr. Frank Stewart (GT Biology) to sequence the microbes’ DNA to study how the microbial population has changed over time. The longest enrichments have been running for over two and a half years, and certain microbial groups that started off as minor players are now dominating. Ongoing work aims to show precisely how these microbes are thriving off of methane and metals. By understanding the influence of iron on methane, and vice versa, the mechanisms controlling methane flux to Earth’s atmosphere can be better resolved, both in the modern and the Archean eras. This research could simultaneously unlock ancient mysteries and potentially provide solutions for a greener future.

Sediments from Lake Matano must be carefully stored in conditions that won’t expose them to the oxygen outside. These sediments are used to grow microbes whose chemistry is studied intently. They reside in a special refrigeration unit in Dr. Glass’ lab at Georgia Tech.

I caught up with Chloe Stanton, an undergraduate EAS major who has worked in the Glass lab since her first semester on campus, to learn more about another project, funded by the NASA Astrobiology Institute’s “Alternative Earths” team. Chloe, EAS PhD candidate Amanda Cavazos, and Dr. Glass are investigating the production of nitrous oxide (also known as “Laughing Gas”) via chemical interactions between iron and reactive nitrogen-containing molecules. Chloe showed me how she carefully concocts small batches of the poisonous gas nitric oxide in a chemical fume hood and makes artificial iron-free seawater from scratch by dissolving individual salts in pure water. She then measures rates of nitrous oxide production from these primitive substrates in an anoxic chamber that mimics the Earth’s ancient oxygen-free atmosphere, with the goal of determining how fast these reactions occurred in the “middle Earth”, or Proterozoic Eon.

Undergraduate researcher Chloe Stanton prepares a sample for study in the Glass Lab’s anoxic chamber.

These two research projects underway in the Glass lab open up some intriguing possibilities. Aside from giving us a better understanding of how the Earth has stayed habitable for microbes over billions of years, this research might be useful to environmental engineering efforts that employ microbes to treat waste water and cut greenhouse gas emissions. Also, the very existence of these microbes greatly broadens the spectrum of conditions under which we know life can develop. Unique assemblages of gas molecules could even be used as “biosignatures” for life on exoplanets outside of our solar system, with significant implications for astrobiology’s search for life elsewhere in the cosmos and new exploration avenues in future space missions.

Thanks for reading, and stay tuned for next week’s journey into science at GT EAS!

Microbes in Wonderland

By Matt Barr

Our expansive journey into the heart of science begins with the story of the hardy microbe.  A single-celled organism that has made its home quite literally everywhere, we are only beginning to discover the fascinating past and potentially revolutionary future that these microscopic organisms share with us.

Microbes be microbin’.  These microbes were found in NASA spacecraft assembly areas – some of the cleanest places on Earth.  Source: NASA JPL.

Microbes can be found everywhere, from the harshest environments to the most sterile.  First discovered in the 1600’s, little information was known about how they actually operated until the late 19^th century.  Even then, most of our detailed observations of microbial activity did not occur until the second half of the 20^th century.  However, once it was understood that microbes inhabit virtually any space where liquid water exists, a new view of life on Earth emerged and opened the door to exciting discoveries in a field of science that has only recently been explored more deeply.

Before delving into the specifics of our research at Georgia Tech, it’s a good idea to establish a context in which the research is being conducted.  That involves explaining where the microbes have been, where they’re going, and how they’re taking us along on their path through history.

A long time ago in a galaxy very, very close by (our own, in fact), the earth looked nothing like it does today.  The land masses we’ve come to know and love, the oxygen that our bodies enjoy breathing on a pleasant spring day (and all of the other days), the warmth of a sun whose luminosity and energy output that allow for those pleasant spring days – all were nowhere to be seen.  Indeed, there were no eyes as we know them with which to see, even if all those lovely life-sustaining conditions were, in fact, anywhere to be seen.

And yet, to quote those immortal words of Jurassic Park’s Dr. Ian Malcolm, “life, uh, finds a way.”

What life though?  Under the harsh conditions that would have burned your lungs, drowned you, choked you to death, or finished you off in any number of other nasty ways, there was a class of life that defied all the odds stacked against it.  We’re talking, of course, about our dear, omnipresent friends known as microbes.

For the first billion or so years of Earth’s history after its accretion (that is, after Earth finished forming into a planet by combining bigger and bigger chunks of rocks, debris, gases, and other materials swirling around our sun in its orbital path), no life seems to have existed.  Indeed, it seems that there was little more than one big ocean and an atmosphere on our planet.  At this magic billion-year mark, however, evidence of the first single-celled organisms begin appearing in the geologic records.  The fascinating aspect of this appearance (one of many) is that our understanding of the conditions under which it’s possible for life to form and sustain itself were very much counter to the conditions present on our planet and in our solar system so long, long, long, long ago.

For starters, we’re fairly certain that a phenomenon referred to as the “faint young sun” was in place.  The faint young sun was precisely that: a star that wasn’t hot enough to warm our planet to a temperature that supported liquid water.  This is a critical piece of information because without liquid water, life as we know it cannot exist.

As the life of a star progresses, it undergoes a process known as the Main Sequence, during which the hydrogen at its core burns at such high temperatures that the hydrogen atoms fuse together to create the next heavier element, helium.

As this process takes place, the star grows hotter and brighter.  However, in what we call the Archaean Eon, that period between 2.5 – 4 billion years ago, our sun’s luminosity and its corresponding energy output were about 70% of what they are today – amounts insufficient to support life.  Yet, the evidence of life is found in our rocks that date from the very Archaean Eon when life was not supposed to exist.  What gives?  What GIVES?!

During the Archaean Eon, our sun was only about 70% as hot and bright as it is today. Following along with the Main Sequence illustrated above, these conditions correspond to a sun that is closer to the blue end. Source: Study.com

It turns out that, thanks to the relatively consistent violent explosions via those angry mountains that we call volcanoes – spewing their lava, ash, and general mayhem, a fairly reasonable (though not entirely accepted!) explanation neatly presents itself.  This is where we need to introduce greenhouse gases like carbon dioxide, methane, water vapor, and nitrous oxide into the conversation.  Some of the most important substances expelled into the atmosphere by volcanoes are, in fact, those infamous greenhouse gases we keep hearing about.  The thing about greenhouse gases is that in certain amounts, they can be very beneficial.  In this case, they appear to have benefited our early earth by keeping it warm enough to host liquid water when the faint young sun wasn’t pulling its weight.

An illustration of greenhouse gas emissions produced by volcanoes. Imagine this process going on at much greater magnitudes and frequencies all over the planet to get an idea of what the Archaean Earth would have been like. These gases likely warmed the planet enough to sustain liquid water, the key ingredient for life as we know it. Source: Wikimedia.org

When we take into consideration that faint young sun, the lack of readily available oxygen in the early atmosphere, and the abundance of these greenhouse gases, our ideas about the development of life on Earth are pushed in a new direction.  The great Carl Sagan was one of the first scientists to suggest that it was these greenhouse gases which warmed the planet enough to allow water to exist as a liquid.  This, in turn, allowed for the earliest life forms to arise much farther back in time than seems plausible, and ultimately develop into the microbes that may have built up our atmosphere into a sort of blanket of habitability through their metabolic processes.

One final component of our microbe picture is that during their metabolism, they can both consume and produce greenhouse gases.  For example, in the presence of iron and methane, a microbe can consume methane and transform it into carbon dioxide.  The way it does this is by interacting with iron and trace metals through something called redox chemistry.  Redox chemistry involves the transfer of electrons between molecules of opposite electrical charges, and can get rather complicated.  For a better idea of how redox chemistry works, check out this site from Washington University.

What’s important to take away from this process is that it can occur without oxygen, which essentially excludes the catalogue of complex life (life that is composed of more than one cell, to be exact) from using it as a way to derive energy.  A deficiency of oxygen is exactly what characterized the Archaean atmosphere.  With liquid water present in abundant amounts due to the warming greenhouse gases being pumped into the atmosphere from volcanic and microbial activity, more and more microbial life could begin to flourish and ultimately begin increasing the oxygen content of the atmosphere.  Gaseous oxygen emitted into the atmosphere is another result of microbial metabolism, and it’s in this way that microbes ultimately paved the way for complex life on our planet to develop.

This interaction with and, specifically, consumption of greenhouse gases also means that microbes are promising partners in the future of environmental engineering processes.  They can clean up wastewater, help us reduce our currently excessive greenhouse gases, and move us in the direction of a cleaner, greener planet.  That is, if we can determine exactly how they work their magic and exactly which microbes are responsible for which chemical processes.

This brings us to the exciting research being conducted in Dr. Jennifer Glass’ lab by her and her students.  Stay tuned for more details and check out Dr. Glass’ website and blog for more in-depth information at jenniferglass.com.