The effect of priming on blue carbon peat in the coastal ocean

News release from Pacific Northwest National Laboratory.

Link to original article; text follows:

 

     
Salt marshes like this one near St. Augustine, Florida, have stored organic carbon for hundreds to thousands of years in a low oxygen environment.

Coastal environments supporting seagrasses, salt marshes and mangroves are storehouses for vast reserves of organic carbon known as blue carbon. These reservoirs have trapped organic carbon beneath the surface for hundreds to thousands of years in a low oxygen environment.

Unfortunately, coastal zones are changing due to rising sea levels and human encroachment. The combination of erosion and habitat destruction is allowing the trapped blue carbon to mix with seawater. Organisms in seawater are consuming the organic carbon and releasing carbon dioxide into the atmosphere.

“There’s growing interest in blue carbon habitats, because they perform a natural and valuable service by sequestering CO2,” says Thomas Bianchi, Jon and Beverly Thompson Endowed Chair of Geological Sciences at the University of Florida. “Coastal plants use the CO2 to grow through photosynthesis, but they also store it for long periods in the soils and sediments they live in. That’s unique, because other plant habitats cycle CO2 out of their soils into the atmosphere much quicker.”

Bottles with peat and algae
The team members made leachates out of peat (the brown one) and stable isotopically labeled algae (the green one). They soaked the materials in water for a day at room temperature in the dark, then filtered the material to leave only the dissolved organic carbon.

Bianchi is a co-principal investigator studying the conversion of blue carbon to CO2as part of a fiscal year 2017 Facilities Integrating Collaborations for User Science proposal. Through FICUS, Bianchi and colleagues will use the expertise and capabilities of EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility at Pacific Northwest National Laboratory, and the DOE Joint Genome Institute, also a DOE Office of Science user facility at Lawrence Berkeley National Laboratory.

The research team includes Co-PIs Andrew Ogram and Todd Osborne, postdoctoral associate Ana Arellano, and graduate students Elise Morrison and Derrick Vaughn, all with the University of Florida; Co-PI Nicholas Ward, a scientist at the Pacific Northwest National Laboratory; and Yina Liu, an EMSL postdoctoral researcher. A self-funded study, support comes from the Thompson endowment and the University of Florida.

“We’re interested in studying what happens when you take this big carbon sink in coastal soils and sediments, and you start carving at it with sea level rise and wave erosion,” says Bianchi. “What controls how quickly that carbon gets converted back into CO2?”

Priming decomposition

Priming is one of the factors affecting the speed stored carbon becomes CO2. For example, microbes have difficulty breaking down straw. Mixing straw with alfalfa accelerates the decomposition process. The microbes quickly eat the alfalfa, but they also break down the straw. The presence of more digestible material primes the straw to be broken down.

Peat priming bottles
The team performed a set of incubations in a temperature-controlled dark room. There were 36 bottles total with four different treatments, three time points for collecting genomic material and three replicates per treatment/time point.

Scientists have studied the priming effect in soils, but few studies have investigated priming in coastal systems. In this study, priming is the mixing of decayed higher plant material (plants with rooted systems) with coastal algae to allow microbes to break it down faster.

“We hypothesized that the breakdown of the stored blue carbon would be much faster in the presence of algae than in the absence of it,” says Bianchi.

Bianchi’s team tested the hypothesis with a series of experiments performed at the University of Florida Whitney Laboratory for Marine Bioscience using seawater, an algae mixture, and coastal peat from Florida wetlands in four treatments – (1) seawater control, (2) seawater and algae mixture, (3) seawater and peat, and (4) seawater, algae mixture and peat. They measured the amount of CO2 produced over time by the four treatments. The team used isotopes as chemical markers to track the source of the CO2 molecules. Samples from these experiments were submitted to EMSL and the DOE JGI for high-resolution measurements of organic carbon composition and microbial genetic responses.

“Our preliminary data supports our hypothesis,” says Bianchi. “In the presence of algae you get more blue carbon peat being converted to CO2.”

The priming effect could be more dramatic as oceans become greener with algae due to pollution from fertilizers and other farm runoff.

Getting to know microbes

Crescent Beach erosion
Crescent Beach, near the University of Florida Whitney Laboratory for Marine Bioscience, after Hurricane Matthew shows how potentially sensitive coastal areas are to erosion (the intracoastal waterway is on the other side of the dunes and the hurricane formed a new inlet).

The project is also using EMSL and DOE JGI capabilities to study microbial communities that convert peat into CO2. They want to know how communities change in the presence and absence of algae. They are also interested in how the microbes decompose peat, including what enzymes they use. The team is using EMSL’s mass spectrometry and nuclear magnetic resonance expertise and capabilities for this portion of the research.

“Being a FICUS project gives us a fantastic opportunity to use two of the best research facilities in the world,” says Bianchi. “Working with EMSL and (DOE) JGI will help us understand how priming works, because we really don’t know all the details about it.”

Bianchi says the study’s findings could improve climate models as the global models scale down. Sophisticated climate models are starting to account for regional effects. The findings could be added to a regional-based model that includes a conversion of land lost to CO2 with priming as an enhancement factor.

“There’s a bigger story,” says Bianchi. “A greener coastal ocean and a destabilized coastal environment due to sea level rise and land use changes are causing a rapid turnover of stored carbon that’s hundreds and thousands of years old being converted into CO2 in part through the priming process.”

Learn more about the current FICUS call for letters of intent, and how you can use the expertise and capabilities at EMSL and the DOE JGI to improve your research.

Undergraduate Research

angelica-at-rice-university

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

bianchi

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

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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”.