Undergraduate Research


Angelica Ares, an undergraduate Biology major working on her research project, within the UF Center for Undergraduate Research, in Dr. Bianchi’s lab was selected to present her research at the Gulf Coast Undergraduate Symposium in October 2016 at Rice University Houston, Texas. She and about 100 other students were selected from universities around the country to make a 15 minute oral presentation on results from their research. Angelica is working under the direction if Bianchi and one of his Ph.D students Xiaowen Zhang, on this project which is funded by the National Science Foundation. This work basically involves the relationship between carbon cycling and the ecohydrology of different vegetational habitats in Big Cyrpress Swamp, in southern Florida. Bianchi is co-PI along with Jon Martin, also in Geological Sciences at UF on this project, which is lead by Matthew Cohen in the UF School of Forest Resources and Conservation.

Dr. Thomas Bianchi Publishes New Book


Cross-posted from the UF Water Institute:

Dr. Thomas Bianchi, Jon and Beverly Thompson Endowed Chair of Geological Sciences, recently published a book titled Deltas and Humans. Bianchi, UF Water Institute Affiliate Faculty member, specializes in global carbon cycling working in coastal, riverine, and ocean environments.

Deltas and Humans focuses on human interaction with major deltas in relation to carbon cycling and sediments. The book is aimed towards an audience with a generalized science background.

Bianchi hopes this book will help individuals understand the intrinsic connections that exist throughout riverine areas. “There is a very sensitive relationship between what we do in altering the watersheds of big rivers and what happens at the coastline,” says Bianchi.

As major rivers flow through numerous countries, Bianchi’s book warns of the future “water wars” due to conflicting interests and demands. “This flow to the delta is really changing,” said Bianchi. “People are extracting more water for damming needs, agricultural needs and population growth. As climate changes, the availability of water is going to become a much more important thing than people realize.”

One of the ironies highlighted in Deltas and Humans is the critical usage of deltas in the development of early civilizations which contrasts to the lack of stability in similar delta regions today. This lack of stability in delta regions has a personal connection to Bianchi as he was personally affected by Hurricane Katrina during his time as faculty at Tulane University, where he lived on the largest delta in the U.S.

Beyond studying these crucial interactions, Bianchi also has additional expertise in organic geochemistry and biogeochemical dynamics of aquatic food chains. He has published 5 other books, has over 180 publications, two Fulbright Research Scholarships, and was made a Fellow of the American Association for the Advancement of Science (AAAS) in 2013. Bianchi looks forward to his future involvement with other faculty as he grows his connection to the UF Water Institute.

For more information about Deltas and Humans, visit Oxford University Press.


Anthrax sickens 13 in western Siberia, and a thawed-out reindeer corpse may be to blame


Cross-posted from the Washington Post.
Article by Ben Guarino

First a heatwave hit Siberia. Then came the anthrax.

Temperatures have soared in western Russia’s Yamal tundra this summer. Across Siberia, some provinces warmed an additional 10 degrees Fahrenheit beyond normal. In the fields, large bubbles of vegetation appeared above the melting permafrost — strange pockets of methane or, more likely, water. Record firesblazed through dry Russian grassland.

In one of the more unusual symptoms of unseasonable warmth, long-dormant bacteria appear to be active. For the first time since 1941, anthrax struck western Siberia. Thirteen Yamal nomads were hospitalized, including four children, the Siberian Times reported. The bacteria took an even worse toll on wildlife, claiming some 1,500 reindeer since Sunday.

According to NBC News, the outbreak is thought to stem from a reindeer carcass that died in the plague 75 years ago. As the old flesh thawed, the bacteria once again became active. The disease tore through the reindeer herds, prompting the relocation of dozens of the indigenous Nenet community. Herders face a quarantine that may last until September.

The governor, Dmitry Kobylkin, declared a state of emergency. On Tuesday, Kobylkin said “all measures” had been taken to isolate the area, according to AP. “Now the most important thing is the safety and health of our fellow countrymen — the reindeer herders and specialists involved in the quarantine.”

Anthrax has broken out in Russia several times, including one outbreak stemming from a 1979 accident at amilitary facility. To the south of Yamal, anthrax may rarely appear when infection spreads from cattle; a man died from such exposure in 2012, the Siberian Times reported.

Zombie bacteria that awaken from old corpses might sound like the stuff of an “X-Files” episode. The premise is far from a complete fiction, however.

For one, anthrax bacteria are hardy microbe. As University of Missouri bacteriologist George Stewart told the Missourian in 2014, the organisms turn into spores in the cold. They play the long game, waiting in the soil for the temperatures to rise. Once it hits a certain threshold, they morph back into a more mobile, infectious state.

In Missouri, anthrax tends to be more worrisome for farmers than for consumers. “It’s more of a threat if you’re a cow,” Stewart told the Missourian. “Cows are killed by anthrax when they pick up the spores when they’re grazing in grass or drinking water out of ponds, and that sort of thing.”

In Russia’s north, however, the situation is different. If the link between an old deer corpse and a new outbreak is confirmed, it will solidify concerns about anthrax some scientists have harbored for years. In 2011, two researchers from the Russian Academy of Sciences writing in the journal Global Health Action assessed the conditions required for anthrax to appear in Yakutia, a region to the east of Yamal that contains 200 burial grounds of cattle that died from the disease.

Citing earlier work from 2007, they estimated anthrax spores remain viable in the permafrost for 105 years. Buried deeper, the bacteria may be able to hibernate for even longer. At the same time, where meteorological data were available they indicate temperatures in Yakutia are increasing.

“As a consequence of permafrost melting, the vectors of deadly infections of the 18th and 19th centuries may come back,” the scientists warned, “especially near the cemeteries where the victims of these infections were buried.” Cattle grave sites should be monitored, they concluded, and “public health authorities should maintain permanent alertness.”

Anthrax microbes are not the only permafrost bacteria that have environmental scientists’ hackles raised. As University of Florida geologist Thomas S. Bianchi wrote at the Conversation in October, as the Arctic warms up it provides more organic matter for cold-climate bacteria to eat. Although the organic matter is ancient, it appears modern bacteria can still digest it. And as they consume the permafrost, the microorganisms excrete carbon dioxide — adding to the greenhouse gases already present in the atmosphere.

Controlled Colorado River flooding released stored greenhouse gases

The 2014 experimental controlled pulse of water to the Colorado River Delta has revealed an interesting twist on how large dry watercourses may respond to short-term flooding events: the release of stored greenhouse gases. This work is reported at the Goldschmidt conference in Yokohama, Japan.

As presenter Dr Thomas Bianchi said:

“We saw a rapid release of greenhouse gases (CH4 and CO2) from the riverbed sediments to the floodwaters. These gases were largely derived from carbon which had been stored in the dry riverbed, perhaps for decades”.

Radiocarbon measurements indicate a resuspension and dissolution of trapped carbon in the riverbed that was released into the flood waters. The dissolved inorganic carbon (DIC, e.g., carbon dioxide, carbonic acid, bicarbonate, and carbonate) was found to be aged (often more than 800 years old) which would suggest that trapped CO2/IC would have been dissolved and released rapidly into the river when flooded.

Thomas Bianchi continued, “This shows that more work is needed to better understand the more unpredictable consequences of floods and droughts on aquatic ecosystems, particularly in the face of global climate change”.

The Colorado River – which carved out the Grand Canyon – is now contained by the Hoover and other dams. It is perhaps North America’s most iconic waterway. Increasing use of water from the Colorado in both the US and Mexico has meant that the Colorado Delta in Mexico, where the river runs into the Gulf of California has largely dried up. The Delta wetlands of the Colorado are now only around 1/20th of their size prior to the Hoover Dam construction.

In 2014, a major 8-week experiment released 130 million cubic metres of water from the Morelos dam (on the border with Mexico and the USA) causing a rise in river levels as far down as the delta. The pulse of water, concentrated around 27-29 March 2014, was aimed at bringing water to delta, which has been starved of water for decades. Scientists were able to look at the before and after conditions, to evaluate how future water releases might affect agricultural crops and natural plant and animal life of the lower delta.

The results of this very brief controlled flooding event showed that some of the carbon stored in the riverbed was rapidly released into the floodwaters, which although not directly measured, also likely allowed for the release of these greenhouse gases to the atmosphere. This indicates the need for a long-term approach, not just for the Colorado, but many other areas in the world that are currently experiencing human-induced changes in water flow.

According to Dr Bianchi (University of Florida) said: “Based on our findings, we suggest that stored carbon in riverbeds (e.g., greenhouse gases) is more likely to be released in a more variable climate, with floods and drought, than under more stable conditions in arid and semi-arid regions. As human needs for water resources continues to increase, the drying and rewetting of once natural river deltas may fundamentally alter the processing and storage of carbon.

There is a lot still to understand. For example, we don’t know how the duration of the wet and dry periods might affect the gas release, or whether maintaining minimum water flow levels might help.

Another factor we need to consider is whether the restored water supply would promote the growth of native plant species in the lower delta. These marsh-like plant communities capture atmospheric carbon and have the potential to store such greenhouse gases in their soils for long periods of time. There are other potential benefits too, for example the restoration of an eroding delta which would lead to coastal stability that should lead to benefits to local fisheries. Resolving these uncertainties is critical for assessing the role of inland waterways on global carbon budgets, identifying potential feedback loops under a changing climate, and planning future flow restoration events.

In practical terms, this means that restoring the river delta is not just a case of opening a tap every now and then: both the US and Mexico need to make a long-term commitment to maintain this complex delicate ecosystem, particularly in a region with such low rainfall. But we think that aiming for restoration is clearly the right thing to do”.

Commenting, Professor Elizabeth A. Canuel (Virginia Institute of Marine Science), said: “This presentation reports an unexpected finding that a short-term controlled flooding event on the Colorado River resulted in the release of greenhouse gases (CH4 and CO2) from the newly wetted riverbed sediments. Generally, production of (GHG) generated from aerobic and anaerobic respiration of organic matter is thought to be higher in dry soils, rather than wet soils. However, as this preliminary study shows, dry river sections can become “hot spots” of biogeochemical transfer and transformation when organic matter and nutrients accumulated in the sediments are “activated” during rewetting phases and first-pulse events such as this controlled flooding event.

Overall, this study provides new insights about biogeochemical responses to flood events. It also has management implications because it shows that release of GHG could be a potential unintended consequence of controlled flood events that will need to be considered against the benefits of these events in terms of restoration and/or other ecological services”.

A Mixed Response: Floodwaters return to the Colorado River but can release greenhouse gases

July 7, 2016
Rachel Wayne, UF News

Deliberately flooding riverbeds left parched by dams has great potential to restore wetlands, but may also have a significant unintended consequence: the release of greenhouse gases.

Despite the findings, the pros of returning rivers to their natural courses and flows generally outweigh the cons, but government officials should consider the research when deciding when and how to alter river flows, said Thomas S. Bianchi, a professor of geological sciences at University of Florida and lead author on the study.

“We need to understand this as it relates to the global carbon budget,” Bianchi said.

If you’ve ever seen an Olympic-sized swimming pool, and can imagine 52,000 of them, you might begin to appreciate the amount of water that was released into the dried-out lower river delta of the Colorado River, as part of an agreement between the U.S and Mexico. Although this may sound like a lot of water, it is still less than 1 percent of what used to flow down the Colorado before all the dams were built on it.

The overall flooding experiment was supported by the U.S. Bureau of Reclamation, U.S.G.S. (United States Geological Survey), International Boundary and Water Commission/ Comisión Internacional de Límites y Agua (IBWC/CILA), and many foundations and donors. Dr. Thomas S. Bianchi, professor at UF, worked in coordination with Dr. Karl Flessa and his graduate student Hector Zamora at the University of Arizona, who led the sampling effort over the eight-week experiment. Bianchi’s group, funded by National Science Foundation- Hydrological Sciences, which included his graduate student Rory Kates and postdocs Drs. Nicholas Ward and Ana Arellano, along with Dr. David Butman at the University of Washington, and Dr. Peter Raymond at Yale University, focused on how the chemistry of the floodwaters changed over time. They found that re-wetting the dried riverbed contributed to the release of dissolved carbon and greenhouse gases (CH4 [methane] CO2 [carbon] dioxide) to the floodwaters. These increases were largely attributed to the release of these gases from the dry riverbed to the floodwaters and presumably to the atmosphere. The age of dissolved carbon coming out from the riverbed was also established using radiometric carbon dating, and indicated that some of carbon may have been stored belowground for thousands of years, and now released by the infiltration of floodwaters.

River management is conducted by the Bureau of Reclamation and IBWC/CILA and the pulse flow was released pursuant to Minute 319 of the U.S.-Mexico Water Treaty of 1944. Bianchi and his team examined how the rapid and controlled release of 130 million cubic meters of water, from the Colorado River at the Morelos Dam on the border of the United States and Mexico, mobilized carbon. The “pulse” of water temporarily flooded the delta, which had been dry for decades.

The Colorado River currently supplies water to 40 million people living in the rivershed. Heavy demand for agricultural, industrial, and municipal purposes has drained the river, which now only rarely reaches the ocean. This drainage created a dry delta near the U.S.–Mexican border, which allowed invasive plants to edge out native flora and disturbed wildlife habitat. The wetlands of the delta have been reduced to 5 percent of their original size since the construction of the Hoover Dam in the 1930s. Restoring water and sediments to the delta would help restore biodiversity to the region, supply water for agriculture, and rebuild the delta, which could help mitigate storm erosion along the coast.

Greenhouse gases, such as carbon dioxide and methane, help to trap the heat on Earth from natural radiation of the sun. Increasing levels of this atmospheric carbon have contributed to global warming. Carbon dioxide and methane concentrations in the atmosphere have increased by about 30 percent and 50 percent, respectively, since the industrial revolution. So, there remains considerable interest in understanding what controls the cycles of these gases.

Carbon dioxide is one type of inorganic carbon compound: when dissolved in water, it forms carbonic acid, which is known for its use in soda water and sparkling juice, but environmentally, contributes to ocean acidification when high levels of atmospheric carbon dioxide dissolve into the seas. Methane, an organic carbon compound, is trapped in water but easily dissipates as a gas produced by decaying organic matter.

When a large dry riverbed is flooded, these greenhouse gases are released into the water, and presumably to the atmosphere. However, re-wetting the delta may support the growth of native plants, which typically are better able to absorb and store carbon than invasive species, and may offset the carbon dioxide and methane released by flooding.

In short, Bianchi’s team and other scientists working on rivers are interested in assessing the costs and benefits of floods and droughts on natural ecosystems, particularly in a world where the climate and water cycles have become more unpredictable, in part due to global warming. Future research may examine how the duration of the flood affects water chemistry, how controlled flooding may support coastal stability and local fisheries, and how flood pulses compare to establishing a steady minimum water flow to the delta.