Earth’s average surface temperature has risen approximately 2.12 degrees Fahrenheit since the late 1800s — most of that rise in the past 40 years, according to NASA. That’s due in large part to the increase of carbon dioxide emissions into the atmosphere, caused by human activity. This has led oceans to warm, ice sheets to melt, and sea levels to rise faster — and it has accelerated the frequency of extreme weather events, such as hurricanes.

When it comes to facing these challenges, “It’s all hands — and all solutions — on deck,” says Susan Lozier, dean and Betsy Middleton and John Clark Sutherland Chair in the College of Sciences at Georgia Tech and president of the American Geophysical Union (AGU). "While we as scientists continue to embrace discovery science, we need to more fully embrace solution space."

Georgia Tech faculty across a number of disciplines are working on projects in ocean science and engineering aimed at identifying, projecting, mitigating, and even reversing the effects of climate change. Many of these researchers are doing so in conjunction with Georgia Tech’s Ocean Science and Engineering (OSE) program and its founding director, Emanuele “Manu” Di Lorenzo, professor of ocean and climate dynamics.

Though the OSE program is relatively new — accepting its first students in 2017 — it has attracted attention for its ability to coordinate and integrate the ocean systems work being done at Georgia Tech and beyond to solve significant problems. “There is a new cohort of people who are needed — problem-solvers of Earth climate, and this involves the ocean,” Di Lorenzo says. “Our hope is that through the OSE program, we will provide students with the tools and the knowledge and resources to be active players as new ocean leaders. This goes beyond them being researchers.”

Read more about the Georgia Tech scientists, engineers, and researchers who are working to reverse the effects of climate change and harness the power of the world’s oceans.

The Ray C. Anderson Foundation has awarded a $300,000 grant to Emory University and its partners for the next phase of the Georgia Climate Project, a state-wide consortium of nine colleges and universities working to strengthen Georgia’s ability to prepare for and respond to a changing climate.

The Georgia Climate Project was founded in 2018 as a collaborative effort between Emory University, the Georgia Institute of Technology, and the University of Georgia. Its scope has since expanded to include Agnes Scott College, Columbus State University, Georgia Southern University, Georgia State University, Spelman College, and the University of North Georgia.

“This partnership is a great example of what can be accomplished when the colleges and universities of our great state work together toward a common goal,” said UGA President Jere W. Morehead. “UGA is proud to be a part of this important effort to promote the wellbeing of our climate as well as the health, environment and economic vitality of Georgia’s communities.”

With this new grant, the project will engage a diverse network of experts to develop and disseminate knowledge on climate impacts and solutions through webinars, workshops, and an online Georgia climate information portal. Priority topic areas include advancing climate justice and racial equity, identifying opportunities for Georgia to build resilience to climate impacts, and supporting the work of Drawdown Georgia, a statewide carbon reduction roadmap. The project will also expand opportunities for student engagement on climate change through internships, coursework, and projects.

“As institutions of higher education, we’re always thinking about our students. How can they put their talents and their passions towards solutions to our biggest challenges, including climate change, while building valuable networks and skills that will serve them beyond their time at Georgia Tech,” said President Ángel Cabrera of Georgia Tech.

“The science is clear that climate change is affecting people in regions across the world, and that includes cities, towns, and rural areas throughout Georgia,” said Emory University President Gregory L. Fenves. “By continuing to partner with universities in the Georgia Climate Project, we can harness the expertise of our faculty and students so that our state can take on one of the defining challenges of our time.”

"As the Georgia Climate Project has already shown, there is so much value that comes from our higher education institutions collaborating on climate - value for students, faculty, businesses, policymakers, and all Georgians,” said John Lanier, Executive Director of the Ray C. Anderson Foundation. “We hope this grant accelerates their work. Georgia is ready to lead on climate, and our colleges and universities have an opportunity to be at the forefront of that leadership."

More information about the Georgia Climate Project is available at GeorgiaClimateProject.org.

For the past six years, multidisciplinary researchers from across the world have been probing northern Minnesota peat bogs in an unprecedented, long-range study of climate change supported by the U.S. Department of Energy. They set out to answer complex questions, including one big one – will future warming somehow release 10,000 years of accumulated carbon from peatlands that store a large portion of earth’s terrestrial carbon?

So the Oak Ridge National Laboratory (ORNL) partnered with the USDA Forest Service to develop a one-of-its-kind field lab in the Marcel Experimental Forest, where below and above ground heating elements are gradually warming the bog in greenhouse-like enclosures big enough to include trees. The enclosures are roofless so that rain and snow can get in.

It’s called the SPRUCE (Spruce and Peatland Responses Under Changing Environments) experiment, and it was designed as a window into what would happen to peat bogs in a warmer world. A recent study, headed by Georgia Institute of Technology microbiologist Joel Kostka and published June 14 in the journal PNAS, provides a sobering outlook.

“The real concern and one of the major conclusions of this paper is that the ecosystem we’re studying is becoming more methanogenic,” said Kostka, professor and associate chair of research in the School of Biological Sciences, who holds a joint appointment in the School of Earth and Atmospheric Sciences and focuses on microbial ecology. “In other words, the warmed bog is enhancing the rate of methane production faster than that for carbon dioxide. This is what we think is going to happen in a warming world, based on our results.”

Testy Little Process

Methanogens are microbes that produce methane, a harmful greenhouse gas that traps up to 30 times more heat than carbon dioxide. Warming the peatland, the researchers found, basically creates a methane production line.

“This occurs because the plant community changes in response to warmer temperatures – mosses decrease and vascular plants increase,” said the paper’s lead author, Rachel Wilson, a researcher with Florida State University’s Department of Earth, Ocean, and Atmospheric Science, where she works in the lab of professor Jeff Chanton, co-author and co-principal investigator of the study.

The process forms a complete cycle: Vascular plants – shrubs and grass-like plants – produce more simple sugars, which are broken down by fermentative bacteria, and the breakdown products then fuel methane-producing microbes use to produce more methane.

While peatlands comprise just 3 percent of the Earth’s landmass, they store about one-third of the planet’s soil carbon. The thinking goes, as global temperatures rise, microbes could break into the carbon bank and the resulting decomposition of the ancient, combustible plant biomass would lead to increased levels of carbon dioxide and methane being released into the atmosphere, accelerating climate change.

“Methane is a stronger greenhouse gas than carbon dioxide,” said Wilson. “Warming the climate stimulates methane production, which will contribute to more warming in a positive feedback loop.”

It’s a scenario that Chanton called, “a critical ecosystem shift. Peat soils that have been stable for thousands of years are giving up the ghost, so to speak. It’s a testy little process.”

Delayed Response

That unpleasant outcome is being delayed somewhat by the extreme conditions found in many peat bogs around the world, including at the SPRUCE experiment site.

“Although most peatlands are in northern regions undergoing some of the most rapid warming on the planet, we’re talking about generally cold, acidic soils where there’s no oxygen,” Kostka noted. “Methanogens grow really slowly under these extreme conditions. We do see their activity increasing with warming, but they’re not yet growing that fast.”

He has a good idea of what could happen, though. Several years ago, Kostka took soil samples from the Minnesota site and tested them in his lab at Georgia Tech, exaggerating the temperature to a much greater degree than would be possible in a large-scale experiment like SPRUCE.

Raising the temperature by 20 degrees Celsius, about twice the temperature range used in the field experiment, “we saw huge increases in methane and large changes in the microbes that break down soil carbon into greenhouse gases,” he said.

It's a sped-up version of what they’re seeing in the field where the research team, Kostka explained, “and it is just beginning to scratch the surface of the changes we’re seeing in this ecosystem.”

Next Chapter

The SPRUCE site experiment involves two kinds of treatment, warming and also elevated carbon dioxide. The warming treatment started in 2014. All of the data sets for the PNAS paper are from 2016. The elevated carbon dioxide treatment began in the final days of data collection, so it wasn’t particularly relevant for this study. “Going forward, we’re thinking the effects of elevated carbon dioxide will be one potential future story to tell,” Kostka said. “This is a long-term experiment and many of these large scale climate change field experiments do not observe substantial changes to microbial communities until 10 years after they start.”

Ultimately, SPRUCE experimental activity is designed and intended to develop a quantitative mechanistic understanding of carbon cycling processes, according to Paul Hanson, the Oak Ridge National Laboratory scientist leading the long-range project as principal investigator.

“SPRUCE provides experimental insights for a broad range of plausible future warming conditions for an established peatland ecosystem, combined with or without elevated carbon dioxide,” Hanson said.

So far, the evidence is pointing to a grim possibility: Warming enhances the production of carbon substrates from plants, stimulating microbial activity and greenhouse gas production, possibly leading to amplified climate-peatland feedbacks. Think, gasoline on a fire.

“That would be the worst case scenario,” Kostka said. “We don’t really know yet how plants and microbes will exchange carbon and nutrients in a warmer world. Will that carbon be locked up by the plants and stored in the soil? Will it be respired by microbes and released as a gas?

 We are just beginning to see major changes in the microbes and plants at the SPRUCE peatland.  Although the first few years of the experiment indicate that a lot more methane will be released to the atmosphere, we will be looking to see if these changes are sustained over the long term.”

CITATIONS:  Rachel M. Wilson, Malak M. Tfaily, Max Kolton, Eric Johnston, Caitlin Petro, Cassandra A. Zalman, Paul J. Hanson, Heino M. Heyman, Jennifer E. Kyle, David W. Hoyt, Elizabeth K. Eder, Samuel O. Purvine, Randy K. Kolka, Stephen D. Sebestyen, Natalie A. Griffiths, Christopher W. Schadt, Jason K. Keller, Scott D. Bridgham, and Jeffrey P. Chanton, and Joel E. Kostka.  “Soil metabolome response to whole ecosystem warming at the Spruce and Peatland Responses Under Changing Environments experiment” (PNAS, June 2021) https://doi.org/10.1073/pnas.2004192118

AERIAL PHOTO: Hanson, P.J., M.B. Krassovski, and L.A. Hook. 2020. SPRUCE S1 Bog and SPRUCE Experiment Aerial Photographs. Oak Ridge National Laboratory, TES SFA, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A. https://doi.org/10.3334/CDIAC/spruce.012 (UAV image number 0050 collected on October 4, 2020).

RELATED LINKS:

“Soil metabolome response to whole ecosystem warming at the Spruce and Peatland Responses Under Changing Environments experiment” 

Joel Kostka – Microbial Ecology

SPRUCE Experiment

“Shaking a Sleeping Bog Monster” (Research Horizons)

NSF Supports Research on the Microbes in Peat Moss

ScienceMatters Podcast: Digging Up Climate Clues in Peat Moss

This story originally appeared on the website of the Harvard John A. Paulson School of Engineering and Applied Sciences. It was written by Leah Burrows.

Centuries-old smoke particles preserved in the ice reveal a fiery past in the Southern Hemisphere and shed new light on the future impacts of global climate change, according to new research published in Science Advances. 

“Up till now, the magnitude of past fire activity, and thus the amount of smoke in the preindustrial atmosphere, has not been well characterized,” said Pengfei Liu, assistant professor in the School of Earth and Atmospheric Sciences, and lead author of the study. (Liu, who received his Ph.D. in Environmental Sciences from Harvard University in 2017, is a former graduate student and postdoctoral fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences.) “These results have importance for understanding the evolution of climate change from the 1750s until today, and for predicting future climate.”

One of the biggest uncertainties when it comes to predicting the future impacts of climate change is how fast surface temperatures will rise in response to increases in greenhouse gases. Predicting these temperatures is complicated since it involves the calculation of competing warming and cooling effects in the atmosphere. Greenhouse gases trap heat and warm the planet’s surface while aerosol particles in the atmosphere from volcanoes, fires and other combustion cool the planet by blocking sunlight or seeding cloud cover. Understanding how sensitive surface temperature is to each of these effects and how they interact is critical to predicting the future impact of climate change.

Looking for clues of smoke aerosols 

Many of today’s climate models rely on past levels of greenhouse gasses and aerosols to validate their predictions for the future. But there’s a problem: While pre-industrial levels of greenhouse gasses are well documented, the amount of smoke aerosols in the preindustrial atmosphere is not. 

To model smoke in the pre-industrial Southern Hemisphere, the research team looked to Antarctica, where the ice trapped smoke particles emitted from fires in Australia, Africa and South America. Ice core scientists and co-authors of the study, Joseph McConnell and Nathan Chellman from the Desert Research Institute in Nevada, measured soot, a key component of smoke, deposited in an array of 14 ice cores from across the continent, many provided by international collaborators.

“Soot deposited in glacier ice directly reflects past atmospheric concentrations so well-dated ice cores provide the most reliable long-term records,” said McConnell.     

What they found was unexpected. “While most studies have assumed less fire took place in the preindustrial era, the ice cores suggested a much fierier past, at least in the Southern Hemisphere,” said Loretta Mickley, Senior Research Fellow in Chemistry-Climate Interactions at SEAS and senior author of the paper.

To account for these levels of smoke, the researchers ran computer simulations that account for both wildfires and the burning practices of indigenous people. 

“The computer simulations of fire show that the atmosphere of the Southern Hemisphere could have been very smoky in the century before the Industrial Revolution. Soot concentrations in the atmosphere were up to four times greater than previous studies suggested. Most of this was caused by widespread and regular burning practiced by indigenous peoples in the pre-colonial period,” said Jed Kaplan, Associate Professor at the University of Hong Kong and a co-author of the study. 

This result agrees with the ice core records that also show that soot was abundant before the start of the industrial era and has remained relatively constant through the 20^th century. The modelling suggests that as land use changes decreased fire activity, emissions from industry increased.   

What does this finding mean for future surface temperatures?

By underestimating the cooling effect of smoke particles in the pre-industrial world, climate models might have over-estimated the warming effect of carbon dioxide and other greenhouse gasses in order to account for the observed increases in surface temperatures. 

“Climate scientists have known that the most recent generation of climate models have been overestimating surface temperature sensitivity to greenhouse gasses, but we haven’t known why or by how much,” said Liu. “This research offers a possible explanation.”

“Clearly the world is warming, but the key question is how fast will it warm as greenhouse gas emissions continue to rise. This research allows us to refine our predictions moving forward,” said Mickley. 

The research was co-authored by Yang Li, Monica Arienzo, John Kodros, Jeffrey Pierce, Michael Sigl, Johannes Freitag, Robert Mulvaney and Mark Curran. It was funded by the National Science Foundation’s Geosciences Directorate under grants AGS-1702814 and 1702830, with additional support from 0538416, 0538427, and 0839093. Georgia Tech also contributed to the research.

Earth’s average surface temperature has risen approximately 2.12 degrees Fahrenheit since the late 1800s — most of that rise in the past 40 years, according to NASA. That’s due in large part to the increase of carbon dioxide emissions into the atmosphere, caused by human activity. This has led oceans to warm, ice sheets to melt, and sea levels to rise faster — and it has accelerated the frequency of extreme weather events, such as hurricanes.

When it comes to facing these challenges, “It’s all hands — and all solutions — on deck,” says Susan Lozier, dean and Betsy Middleton and John Clark Sutherland Chair in the College of Sciences at Georgia Tech and president of the American Geophysical Union (AGU). "While we as scientists continue to embrace discovery science, we need to more fully embrace solution space."

Georgia Tech faculty across a number of disciplines are working on projects in ocean science and engineering aimed at identifying, projecting, mitigating, and even reversing the effects of climate change. Many of these researchers are doing so in conjunction with Georgia Tech’s Ocean Science and Engineering (OSE) program and its founding director, Emanuele “Manu” Di Lorenzo, professor of ocean and climate dynamics.

Though the OSE program is relatively new — accepting its first students in 2017 — it has attracted attention for its ability to coordinate and integrate the ocean systems work being done at Georgia Tech and beyond to solve significant problems. “There is a new cohort of people who are needed — problem-solvers of Earth climate, and this involves the ocean,” Di Lorenzo says. “Our hope is that through the OSE program, we will provide students with the tools and the knowledge and resources to be active players as new ocean leaders. This goes beyond them being researchers.”

Read more about the Georgia Tech scientists, engineers, and researchers who are working to reverse the effects of climate change and harness the power of the world’s oceans.

Scientists have long thought that there was a direct connection between the rise in atmospheric oxygen, which started with the Great Oxygenation Event 2.5 billion years ago, and the rise of large, complex multicellular organisms. 

That theory, the “Oxygen Control Hypothesis,” suggests that the size of these early multicellular organisms was limited by the depth to which oxygen could diffuse into their bodies. The hypothesis makes a simple prediction that has been highly influential within both evolutionary biology and geosciences: Greater atmospheric oxygen should always increase the size to which multicellular organisms can grow. 

It’s a hypothesis that’s proven difficult to test in a lab. Yet a team of Georgia Tech researchers found a way — using directed evolution, synthetic biology, and mathematical modeling — all brought to bear on a simple multicellular lifeform called a ‘snowflake yeast’. The results? Significant new information on the correlations between oxygenation of the early Earth and the rise of large multicellular organisms — and it’s all about exactly how much O₂ was available to some of our earliest multicellular ancestors. 

“The positive effect of oxygen on the evolution of multicellularity is entirely dose-dependent — our planet's first oxygenation would have strongly constrained, not promoted, the evolution of multicellular life,” explains G. Ozan Bozdag, research scientist in the School of Biological Sciences and the study’s lead author. “The positive effect of oxygen on multicellular size may only be realized when it reaches high levels.”

“Oxygen suppression of macroscopic multicellularity” is published in the May 14, 2021 edition of the journal Nature Communications. Bozdag’s co-authors on the paper include Georgia Tech researchers Will Ratcliff, associate professor in the School of Biological Sciences; Chris Reinhard, associate professor in the School of Earth and Atmospheric Sciences; Rozenn Pineau, Ph.D. student in the School of Biological Sciences and the Interdisciplinary Graduate Program in Quantitative Biosciences (QBioS); along with Eric Libby, assistant professor at Umea University in Sweden and the Santa Fe Institute in New Mexico.

Directing yeast to evolve in record time 

“We show that the effect of oxygen is more complex than previously imagined. The early rise in global oxygen should in fact strongly constrain the evolution of macroscopic multicellularity, rather than selecting for larger and more complex organisms,” notes Ratcliff. 

“People have long believed that the oxygenation of Earth's surface was helpful — some going so far as to say it is a precondition — for the evolution of large, complex multicellular organisms,” he adds. “But nobody has ever tested this directly, because we haven't had a model system that is both able to undergo lots of generations of evolution quickly, and able to grow over the full range of oxygen conditions,” from anaerobic conditions up to modern levels.  

The researchers were able to do that, however, with snowflake yeast, simple multicellular organisms capable of rapid evolutionary change. By varying their growth environment, they evolved snowflake yeast for over 800 generations in the lab with selection for larger size. 

The results surprised Bozdag. “I was astonished to see that multicellular yeast doubled their size very rapidly when they could not use oxygen, while populations that evolved in the moderately oxygenated environment showed no size increase at all,” he says. “This effect is robust — even over much longer timescales.” 

Size — and oxygen levels — matter for multicellular growth 

In the team’s research, “large size easily evolved either when our yeast had no oxygen or plenty of it, but not when oxygen was present at low levels,” Ratcliff says. “We did a lot more work to show that this is actually a totally predictable and understandable outcome of the fact that oxygen, when limiting, acts as a resource — if cells can access it, they get a big metabolic benefit. When oxygen is scarce, it can't diffuse very far into organisms, so there is an evolutionary incentive for multicellular organisms to be small — allowing most of their cells access to oxygen — a constraint that is not there when oxygen simply isn't present, or when there's enough of it around to diffuse more deeply into tissues.”

Ratcliff says not only does his group’s work challenge the Oxygen Control Hypothesis, it also helps science understand why so little apparent evolutionary innovation was happening in the world of multicellular organisms in the billion years after the Great Oxygenation Event. Ratcliff explains that geologists call this period the “Boring Billion” in Earth’s history — also known as the Dullest Time in Earth's History, and Earth's Middle Ages — a period when oxygen was present in the atmosphere, but at low levels, and multicellular organisms stayed relatively small and simple.

Bozdag adds another insight into the unique nature of the study. “Previous work examined the interplay between oxygen and multicellular size mainly through the physical principles of gas diffusion,” he says. “While that reasoning is essential, we also need an inclusive consideration of principles of Darwinian evolution when studying the origin of complex multicellular life on our planet.” Finally being able to advance organisms through many generations of evolution helped the researchers accomplish just that, Bozdag adds.

This work was supported by National Science Foundation grant no. DEB-1845363 to W.C.R, NSF grant no. IOS-1656549 to W.C.R., NSF grant no. IOS-1656849 to E.L., and a Packard Foundation Fellowship for Science and Engineering to W.C.R. C.T.R. and W.C.R. acknowledge funding from the NASA Astrobiology Institute.

A map of any ocean or sea looks like a big, blue, basic body of water. Within that body of water, though, are distinct marine ecological regions, or ecoregions — distinct areas defined by their “biogeographic” characteristics. Individual ecoregions contain specific water masses, have generally similar environmental resources in terms of quantity and quality, and may also host unique marine species.

But experts have long run into choppy waters when trying to precisely define these ecoregions and how they relate to each other. A lack of data for regions that are not adjacent to coastal areas exacerbates the issue, along with the large-scale dispersal potential of ocean currents, which can impact factors like species migration from one region to the next. Ocean currents and water characteristics also change in space and time on scales of just a few months, and tens of kilometers — and biological communities can respond to these changes in similar scales of time and space. 

Now, a study by School of Earth and Atmospheric Sciences researchers, published this month in the journal NatureScientific Reports, is charting a new path to help scientists create tools to locate ecoregions and predict community susceptibility to those changes.

“Uncovering marine connectivity through sea surface temperature” suggests a new way to find these ecoregions and then connect them, thanks to recent advances in more than 40 years of satellite data that tracks surface temperatures that are indirectly related to ocean currents — as well as progress with computer science algorithms. 

“We are now poised to define ecoregions that meaningfully delimit marine biological communities based on their connectivity, and to follow their evolution through time,” write the co-authors: professor Annalisa Bracco, graduate student Fabrizio Falasca, and one of Bracco’s visiting students, Ljuba Novi from the Institute of Geosciences and Earth Resources (part of the National Research Council in Pisa, Italy). 
 

Through a time-dependent complex network framework applied to a 30-year dataset of sea surface temperatures in the Mediterranean Sea, Bracco says she and her team provide compelling evidence that ocean “ecoregionalization” based on connectivity can be achieved at space and time scales relevant to conservation management and planning. 


The researchers note that that’s particularly important for any future sustainable uses of oceans, since their resources require protection, conservation, and restoration of marine species biodiversity. 

“To achieve this goal, the identification of ecoregions and their connectivity in time and space is a key first step to developing effective strategies for targeted management — for example, figuring out where to implement marine protected areas,” Bracco explains. “The potential of a marine protected area to retain biodiversity and restock species abundance beyond its border is inherently linked to some form of regional discretization and population connectivity, such as larval and juvenile dispersal, or seeding across ecoregions.”  

At the same time, the framework the study proposes allows for looking at ecoregions across time. “We can easily figure out if changes in currents are affecting regions where there is a high biodiversity, or check quickly how currents help or block invasive species.” Bracco’s team found that in the Mediterranean Sea, the invasion of the lionfish was halted by the fragmentation of the ecoregions in the late 1990s and early 2000s, and that it has also been helped by ocean currents since 2011. 

Bracco and her researchers discovered the lionfish data thanks to new and higher resolution sea surface temperature data products that were previously unavailable to scientists. 

For the analysis and the identification of ecoregions and their links, Bracco’s team also adapted a complex network methodology developed at Georgia Tech by a group led by Constantine Dovrolis, who serves as a professor in the School of Computer Science within the College of Computing.

The authors write that future studies of ecoregionalization should be an interdisciplinary approach involving physical, biological, and ecological oceanographers, since “ecoregions are essential units of comparative analysis in the assessment, management and solution of ecosystems problems.”

A Georgia Tech Faculty Development Grant assisted with funding for this research (Novi, L., Bracco, A. & Falasca, F. Uncovering marine connectivity through sea surface temperature. Sci Rep 11, 8839 (2021). https://doi.org/10.1038/s41598-021-87711-z)