Moore Foundation Funds MBL Teams for Symbiosis Research | The Well

Posted 1 week, 1 day ago @

The Gordon and Betty Moore Foundation’s Symbiosis in Aquatic Systems Initiative is investing $19 million over the next three years to support 42 teams of scientists, including four teams with MBL researchers, to collaboratively develop tools and methods to advance model systems in aquatic symbiosis. The Initiative’s funding aims to equip the scientific community with Moore Foundation Funds MBL Teams for Symbiosis Researchinfrastructure such as new genetic tools, cultivation methods, and nanoscale microscopy to improve experimental capabilities in aquatic symbiosis research over the coming decade. Read more about the initiative …

The MBL scientists funded in this grant include:

Project title: Underground Allies: Dynamic Interactions Among Cordgrass (Spartina alterniflora) and Sulfur-Cycling Microbes in the Rhizosphere
Principal Investigator: Zoe Cardon, MBL
Co-Investigators: Anne Giblin, Elena L. Peredo, Blair Paul, and Emil Ruff, MBL

Summary: Spartina alterniflora  is a native cordgrass dominating intertidal salt marsh platforms along thousands of miles of the U.S. East and Gulf coasts. The interaction among Spartina roots, sulfate reducing bacteria, and sulfur oxidizing bacteria is at the core of salt marsh health. We aim to establish a model system for understanding mechanisms underlying this symbiosis using plants and microbes isolated from the Plum Island Ecosystem Long Term Ecological Research site north of Boston. The Spartina root system and its associated sulfur-cycling microbes control an ecosystem-scale production, recycling and detoxification system, maintaining vast expanses of clonal Spartina that are crucibles for marine coastal life, and creating peat platforms critical for salt marsh persistence in the face of rising sea levels.

Read the complete story on The Well...

UMass Amherst Microbiologists Clarify Relationship Between Microbial Diversity and Soil Carbon Storage | UMass Amherst News

Posted 1 week, 2 days ago @

More diverse soils did perform better, but drought stress found to be a limiting factor

In what they believe is the first study of its kind, researchers led by postdoctoral researcher Luiz A. Domeignoz-Horta and senior author Kristen DeAngelis at the University of Massachusetts Amherst report that shifts in the diversity of soil microbial communities can change the soil’s ability to sequester carbon, where it usually helps to regulate climate.

They also found that the positive effect of diversity on carbon use efficiency – which plays a central role in that storage – is neutralized in dry conditions. Carbon use efficiency refers to the carbon assimilated into microbial products vs carbon lost to the atmosphere as CO2 and contributing to climate warming, DeAngelis explains. Among other benefits, soil carbon makes soil healthy by holding water and helping plants grow.

She and colleagues addressed these questions because they point out, “empirical evidence for the response of soil carbon cycling to the combined effects of warming, drought and diversity loss is scarce.” To explore further, they experimentally manipulated microbial communities while varying factors such as microbe community species composition, temperature and soil moisture. Details are in Nature Communications.

In addition to first author Domeignoz-Horta and others at UMass Amherst, the team includes Serita Frey at the University of New Hampshire and Jerry Melillo at the Ecosystems Center, Woods Hole, Mass.

Read the complete story from the News Office at UMass, Amherst.

Desert Algae Shed Light on Desiccation Tolerance in Green Plants | The Well

Posted 3 weeks, 5 days ago @

 

WOODS HOLE, Mass. — Deserts of the U.S. Southwest are extreme habitats for most plants, but, remarkably, microscopic green algae live there that are extraordinarily tolerant of dehydration. These tiny green algae (many just a few microns in size) live embedded in microbiotic soil crusts, which are characteristic of arid areas and are formed by communities of bacteria, lichens, microalgae, fungi, and even small mosses. After completely drying out, the algae can become active and start photosynthesizing again within seconds of receiving a drop of water.

Acutodesmus deserticola, a desert-derived green algae, grows in liquid culture at MBL. This alga’s cells are tiny but extremely resilient, capable of surviving multiple cycles of desiccation and rehydration in a single day. Credit: E.L. Peredo.

Acutodesmus deserticola, a desert-derived green algae, grows in liquid culture at MBL. This alga’s cells are tiny but extremely resilient, capable of surviving multiple cycles of desiccation and rehydration in a single day. Credit: E.L. Peredo.

How are they so resilient? That question is at the core of research by Elena Lopez Peredo and Zoe Cardon of the Marine Biological Laboratory (MBL), published this week in Proceedings of the National Academy of Sciences. Given the intensified droughts and altered precipitation patterns predicted as the global climate warms, understanding the adaptations that facilitate green plant survival in arid environments is pressing.

Working with two particularly resilient species of green microalgae (Acutodesmus deserticola and Flechtneria rotunda), Peredo and Cardon studied up- and down-regulation of gene expression during desiccation, and added a twist. They also analyzed gene expression in a close aquatic relative (Enallax costatus) as it dried out and ultimately died. Surprisingly, all three algae – desiccation tolerant or not – upregulated the expression of groups of genes known to protect even seed plants during drought. But the desiccation-tolerant algae also ramped down expression of genes coding for many other basic cellular processes, seemingly putting the brakes on their metabolism. The aquatic relative did not.

Peredo’s and Cardon’s research suggests this new perspective on desiccation tolerance warrants investigation in green plants more broadly. Upregulation of gene expression coding for protective proteins may be necessary but not sufficient; downregulation of diverse metabolic genes may also be key to survival.

Citation: Elena L. Peredo and Zoe G. Cardon (2020) Shared upregulation and contrasting downregulation of gene expression distinguish desiccation tolerant from intolerant green algae. PNAS, doi: 10.1073/pnas.1906904117

Homepage photo: Desiccation-tolerant green microalgae are frequently found in the microbiotic crusts covering soil in arid areas, such as the deserts of the Southwestern U.S.A. (Credit: Z.G. Cardon).

—###—

The Marine Biological Laboratory (MBL) is dedicated to scientific discovery – exploring fundamental biology, understanding marine biodiversity and the environment, and informing the human condition through research and education. Founded in Woods Hole, Massachusetts in 1888, the MBL is a private, nonprofit institution and an affiliate of the University of Chicago.

Originally posted on The Well.

New DOE Award | Sticky Roots and the Fate of Soil Carbon in Natural Ecosystems

June 30th, 2020 @

MBL Ecosystems Center Senior Scientist Zoe Cardon has received a collaborative grant from the U.S. Department of Energy (DOE) to study "sticky roots" and the fate of soil carbon in natural ecosystems. This grant was one of nine funded under the DOE Environmental Systems Science Program aimed at improving the understanding of watersheds, wetlands, and other terrestrial environments.  The official press release may be found on the Office of Science website.

Grass roots grown in soil, ready for imaging. (Zoe Cardon)

Grass roots grown in soil, ready for imaging. [Photo credit: Zoe Cardon]

Human activities are driving increasing concentrations of CO2 in the atmosphere, and the resulting climate change is becoming more and more obvious. But there are natural mechanisms operating in ecosystems that can transform atmospheric CO2 into organic forms and store it in soil long-term. In particular, that organic matter can become bound to soil minerals, where it can remain protected for millennia. Such long-term protection has great value to humans as climate change looms. However, the growth of living plants and soil microbes may depend on accessing nutrients trapped in the mineral-associated organic matter. In this DOE-funded work, Cardon (MBL), Keiluweit (UMass Amherst), Malmstrom (MSU), and Riley (LBNL) are using experiments and modeling to examine mechanisms by which plant roots and their associated microbes can dislodge organic matter from soil minerals, making nutrients available for recycling supporting new growth, but also making carbon vulnerable to re-release to the atmosphere as CO2.

Switchgrass growing at the MBL Research Greenhouse in root imaging boxes. [Photo credit: Zoe Cardon]

Switchgrass growing at the MBL Research Greenhouse in root imaging boxes. (Zoe Cardon)

A novel twist of the planned work lies in the aboveground treatment through which the researchers will test belowground ecosystem function: controlled viral infection of plants. Viral infection strongly affects the types and amounts of compounds released by plant roots, and Cardon and colleagues hypothesize that some of those compounds can dislodge stored organic matter from minerals. Since viral infection of plants is widespread in terrestrial ecosystems (with 25-70% of plants commonly infected), this new work promises to build knowledge about a prevalent, natural phenomenon with large potential to affect the productivity of ecosystems and the fate of large reserves of carbon stored in soil.

 

Lauren Johnson earns MBL Associates Prize for Excellence | The Well

February 26th, 2020 @

Lauren JohnsonLauren Johnson—student of Trinity University in San Antonio, Texas—was awarded the MBL Associates Prize for Excellence in Independent Research in the Semester in Environmental Science (SES). The prize, sponsored by Friends of the MBL, was awarded based on her presentation at the 23rd annual SES student research symposium, which was held at the MBL in December 2019.  Johnson’s research explored the effects of nutrients and agitation on carbon update and isotopic composition in the macroalga Ulva lactuca.

According to her advisor, MBL Research Scientist Javier Lloret, Johnson’s work provided “fresh insights” into claims in the literature that Ulva can switch between 3-carbon and 4-carbon photosynthetic pathways during nutrient limitation. Evidence for this “switch” has been based on changes in the isotopic composition of the algae thought to occur when high nutrient supply stimulates rapid algae growth. Johnson demonstrated that similar isotopic changes could also be induced by diffusion limitation of carbon uptake.

“Lauren did a superb job of fielding questions after her presentation,” said Lloret.

Originally published on The Well

Marine Microorganisms, Ocean Chemistry, and Thermodynamics | Future Health Tech

January 31st, 2020 @

MBL Senior Scientist Joseph Vallino chats marine microorganisms, ocean chemistry, and thermodynamics with the Future Tech Health Podcast team. 

By: Future Tech Health PodcastJoseph Vallino on Future Tech Health Podcast

At the Marine Biological Laboratory, Senior Scientist Joseph Vallino is researching how microbes impact the chemistry of the ocean.

He joins the podcast to discuss his work in the field of biogeochemistry, which includes questions like the following:

What dictates the distribution of microbes and what types of metabolic activities they carry out in ocean water. How the dissipation of energy gradients in nonliving systems works, and how this idea can be applied to biological systems to better understand how living organisms organize. How the theory of maximum entropy production relates to marine biology and microbial function. There are thousands of different species of bacteria and phytoplankton in just one liter of ocean water, and billions of individual microbes. Since they all carry out different metabolic processes at different times and in different locations, it can be difficult to develop a holistic understanding of the complex chemistry that’s occurring in the ocean. Learn more…

Source: Marine Microorganisms, Ocean Chemistry, and Thermodynamics—Joseph Vallino—Marine Biological Laboratory

Making "Lemonade": Chance Observation Leads to Insight on Microbial Bloom Formation

January 30th, 2020 @

A scientific discovery often starts with a chance observation made by open minds who realize its potential. This happens over and over again in the MBL’s Advanced Research Training courses.

Sampling at the Trunk River Lagoon. The sulfur bloom is the yellow patch at left. Credit: Emil Ruff

A Microbial Diversity course student sampling at Trunk River Lagoon, Falmouth. The yellow patch at left is a natural bloom of sulfide-oxidizing phototrophs. Credit: Elise Cowley

In 2014, students and faculty in the MBL’s Microbial Diversity course made such a serendipitous observation. A team followed up on it in the coming years and last week, published their insights in the journal Environmental Microbiome.

The story started at Trunk River lagoon, near the Shining Sea Bike Path in Falmouth, Mass., which for decades has been a “natural laboratory” for the Microbial Diversity course along with other local field sites, such as Sippewissett Marsh. (The course, established at MBL in 1971 by Holger Jannasch, will celebrate its 50th anniversary this year).

“A few days after we had waded through the shallow section of Trunk River lagoon, our footprints turned yellow,” says senior author Emil Ruff, a course teaching assistant in 2014-15 and now a scientist at the MBL.

Ruff hypothesized that the yellow suspension (which the course participants called microbial “lemonade”) was a sulfur bloom generated by microorganisms that couple photosynthesis to the oxidation of sulfur. The students’ footsteps likely stirred up decaying sea grass and other organic material, releasing sulfide into the water and creating a habitat suitable for rare microbes to bloom.

Lead authors (l-r) Srijak Bhatnager, Elise S. Cowley and Emil Ruff at Trunk River Lagoon. Bhatnager and Cowley were Microbial Diversity course students and Ruff was a teaching assistant when this research began. Credit: Emil Ruff

Lead authors (l-r) Srijak Bhatnagar, Elise S. Cowley and Emil Ruff after sampling at Trunk River Lagoon. All three were Microbial Diversity teaching assistants and led the research team (self-dubbed “Lemonheads”) that completed the study. Credit: Emil Ruff

Blooms of microorganisms are not uncommon in water bodies. Some are so huge that they are visible from satellites. Some are harmful, because they can be toxic for animals, or lead to oxygen depletion in certain areas of the ocean. Blooms generated by high sulfide concentrations are generally a concern, as they can become toxic for fish, mussels and birds. There are many open questions about what triggers bloom formation and collapse.

The next year, Ruff and a team from the Microbial Diversity course returned to Trunk River with the goal of intentionally creating and tracking blooms to study how microbial communities form and change over time. They dug holes in the lagoon and added poles that allowed them to sample daily from several depths without disturbing the water column.

“Often in microbial ecology, we try to understand an ecosystem in its steady state. But it remains unclear how long it takes for an ecosystem to recover after a disturbance and what it takes to establish a diverse [microbial] community,” says Ruff. The experimental design allowed the research team to follow the microbial community as it began to assemble, matured and stratified over time, and collapsed at the end of the bloom.

Understanding these dynamics is particularly important in estuarine ecosystems, such as Trunk River lagoon, that are exposed to natural and human disturbances. Estuaries not only provide important protection from coastal erosion, they also capture carbon from the atmosphere and sequester it. They also serve as a food source and breeding ground for much of the coastal biodiversity.

“The ecology and biogeochemistry causing the sulfur-driven blooms showed us how quickly things can turn, and how ecosystems and microbiomes can rapidly change upon disturbances,” says Ruff.

The Microbial Diversity course team sampling at Trunk River. Credit: Drone photo by Rhys Probyn

The Microbial Diversity course team sampling at Trunk River. Credit: Drone photo by Rhys Probyn

One surprising finding was where the bloom’s microbes — called anoxygenic phototrophs — found optimal living conditions. Prior to the study, it was generally thought that many of the bloom microbes could not grow in the presence of oxygen. Finding them in mildly oxic waters led the researchers to examine their genomes. They found that certain species of Chlorobiales – the bacterial lineage responsible for most of the bloom biomass and the yellow color — encode enzymes that combat oxygen stress, which could explain the microbes’ oxygen tolerance. This and other insights have already initiated new course research projects.

Like the different functions of the microbes in the Trunk River estuarine community, the Microbial Diversity course brings together teaching fellows, faculty and students with diverse backgrounds and research foci.

“What I found remarkable is the range of expertise in the course,” says Ruff. “You can assemble a group of researchers that can look at all aspects of an ecosystem, including microbiology, physics, chemistry and everything in between. This holistic approach is what the course stands for and passes on to its students each year, for the past 49 years.”

Citation: Srijak Bhatnagar et al (2019) Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom. Environmental Microbiome, DOI: 10.1186/s40793-019-0348-0

By Jennifer Tsang

This work was carried out at the Microbial Diversity course at the Marine Biological Laboratory in Woods Hole, Mass. The course was supported by grants from National Aeronautics and Space Administration, the US Department of Energy, the Simons Foundation, the Beckman Foundation, and the Agouron Institute.

—###—

The Marine Biological Laboratory (MBL) is dedicated to scientific discovery – exploring fundamental biology, understanding marine biodiversity and the environment, and informing the human condition through research and education. Founded in Woods Hole, Massachusetts in 1888, the MBL is a private, nonprofit institution and an affiliate of the University of Chicago.

Synthetic Biology: A New Tool to Tackle Climate Change? | MIT Global Change

December 12th, 2019 @

On December 3 and 4, Boston University convened a workshop exploring how synthetic biology—the engineering of genetic “circuits” in living cells and organisms to enable them to perform specified tasks—can help address climate change.Synthetic Biology: A New Tool to Tackle Climate Change? | MIT Global Change

Participants, who included thought leaders in science, economics, policy and ethics, considered a wide range of complex challenges and potential benefits of proposed synthetic biology approaches to reducing greenhouse gas emissions.

Among the presenters and moderators were four researchers affiliated with the MIT Joint Program on the Science and Policy of Global Change who explored some of the scientific and policy implications of tackling climate change with a synthetic biology toolset.

In a session on land, atmosphere and ocean systems, Jerry Melillo, a senior scientist at the Marine Biological Laboratory, highlighted the strong interactions among carbon, nitrogen and phosphate cycles that present opportunities and limits to any biological solution to mitigating greenhouse gases (GHGs). He observed that it will likely take decades of monitoring to fully understand how ecosystems and soils respond to human-initiated changes in the climate system. Read more …

Photo: MIT biological engineers have devised a programming language that can be used to give new functions to E. coli bacteria. Image: Janet Iwasa

By Mark Dwortzan

Source: Synthetic biology: A new tool to tackle climate change? | MIT Global Change

Zoe Cardon, MBL Ecosystems Center, elected to ESA's Governing Board

November 18th, 2019 @

Ecological Society of America Announces New Members Elected to Governing Board

The Ecological Society of America (ESA) is proud to announce the election results for its governing board members. Those selected by the membership to serve are Member-at-Large Zoe Cardon, Ecosystems Center at Marine Biological Laboratory; Vice President for Finance Jeannine Cavender-Bares, University of Minnesota; President-Elect for 2020 Dennis Ojima, Colorado State University; Vice President for Public Affairs Laura Petes, NOAA Office for Coastal Management; and Member-at-Large Sasha Reed, research ecologist.

"With the newest members elected to the ESA governing board, the Society will continue the tradition of strong leadership and dedication to the science of ecology,” says ESA President Osvaldo Sala. “I look forward to the new perspectives and experiences they will bring when their terms begin in August 2020, and I offer congratulations to each person joining the board.”

President-Elect for 2020 Dennis Ojima is a professor emeritus at Colorado State University in the Department of Ecosystem Science and Sustainability and a senior research scientist at the Natural Resource Ecology Laboratory. An ESA member since 1984, his research applies social-ecological approaches to climate and land use changes in dryland and grassland systems worldwide, including Mongolia, China, Central Asia, parts of Africa, and in the U.S. Ojima is instrumental in the development of many international science programs; he is named Champion of the Environment by the Mongolian government and is recognized for his contributions to the Millennium Ecosystem Assessment and the International Panel on Climate Change. He is also active in training young scholars and professionals in social-ecological system approaches to dealing with climate change impacts and responses in the United States and Asia.

“I am honored to be selected as President-Elect of the Ecology Society of America,” says Ojima. “Serving ESA over the coming years, and representing the members in their quest to pursue sound ecological research and to provide a platform to engage and communicate with civil society will be a role I will execute with integrity and with members’ guidance.”

Vice President for Public Affairs for the term of 2020-2023, Laura Petes is the manager of the Coastal Communities Program in the National Oceanic and Atmospheric Administration (NOAA) Office for Coastal Management. Petes has conducted research on coral disease and on the physiological ecology of rocky intertidal mussels, and she previously served as assistant director for climate adaptation and ecosystems at the White House Office of Science & Technology Policy (OSTP). There, she led the OSTP resilience portfolio under President Obama’s Climate Action Plan and launched a Climate Education and Literacy Initiative, which engaged federal agencies, companies, non-governmental organizations, and hundreds of students and educators. Petes is currently serving a second term on the ESA Public Affairs Committee.

Jeannine Cavender-Bares, a professor at the University of Minnesota, will serve as vice president for finance for the term of 2020-2023. She is interested in plant function, integrating ecology and evolution, and exploring ways to detect biodiversity and ecological processes. Over the last two decades, Cavender-Bares has led major research grants from multiple federal and state institutions and managed budgets for these projects, and she currently serves on NSF’s Biological Sciences Advisory Committee and its NEON subcommittee. As vice president for finance, she will aim to work with the Society to invest in activities that benefit ESA members while maintaining the Society’s solid financial path.

An elected member-at-large for the term 2020-2022, Zoe Cardon is a senior scientist at the Ecosystems Center, Marine Biological Laboratory (MBL), located in Woods Hole, Massachusetts. She is an ecosystems ecologist with roots in mechanistic plant physiology, and she considers ESA her “home” Society. Her diverse career path includes prior positions with UC Berkeley, Bowdoin College, and the University of Connecticut. Cardon works to build interdisciplinary communities supporting training and collaboration essential for understanding and sustaining Earth’s life support systems.

Sasha Reed, also elected a member-at-large for the term 2020-2022, works as an ecosystems ecologist and biogeochemist focusing on understanding how terrestrial ecosystems work and respond to change. She believes in linking relevant and accessible science with those who can use it; enjoys addressing complex problems with diverse groups; and thinks highly of the power of strong mentorship. Reed serves on a number of boards and committees, including ESA’s Publications Committee and on the Advisory Board for ESA’s Issues in Ecology.

“I continue to be impressed with the dedication of ESA’s volunteers that step up for board service,” says ESA Executive Director Catherine O’Riordan. “I want to extend a big thank you to the membership; this election process is important for providing the vision and voices needed to guide the Society’s efforts to positively affect and advance the community and science of ecology.”

The current ESA Governing Board Members are President Osvaldo Sala, professor, Arizona State University through August 2020; Immediate President-Elect Kathleen Weathers, senior scientist, Cary Institute of Ecosystem Studies; Immediate Past-President Laura Huenneke, emeritus professor, Northern Arizona University; Vice President for Science Diane Pataki, professor, University of Utah; Vice President for Finance Evan DeLucia, professor, University of Illinois Urbana-Champaign; Vice President for Public Affairs Frank Davis, professor, University of California, Santa Barbara; Vice President for Education and Human Resources, Pamela Templer, professor, Boston University; Secretary, Jessica Gurevitch, professor, Stony Brook University; Member-at-Large Manuel Morales, professor, Williams College; Member-at-Large Kathleen Treseder, professor, University of California, Irvine; and Member-at-Large Jacquelyn Gill, associate professor, University of Maine.

###

The Ecological Society of America (ESA), founded in 1915, is the world’s largest community of professional ecologists and a trusted source of ecological knowledge, committed to advancing the understanding of life on Earth. The 9,000 member Society publishes five journals and a membership bulletin and broadly shares ecological information through policy, media outreach, and education initiatives. The Society’s Annual Meeting attracts 4,000 attendees and features the most recent advances in the science of ecology. Visit the ESA website at http://www.esa.org.

Original press release and photos online: https://www.esa.org/blog/2019/11/15/ecological-society-of-america-announces-new-members-elected-to-governing-board

Contact: Alison Mize, 202-833-8773, alison@esa.org

Inside Science | Warming Tropical Soils May Release Huge Amounts of Stored Carbon

October 2nd, 2019 @

The heat-trapping gases humans release into the air are warming the planet. But humble soil-dwelling bacteria and fungi also release heat-trapping gases, and those gases could determine just how hot it gets. Now new research adds to the worry that the microbes will make climate change worse.

Soil microbes digest dead plants and animals. And, like us, they "breathe out" carbon dioxide. Some scientists predict that as temperatures rise, bacteria and fungi will speed up their metabolisms, spewing vast stores of carbon from the soil into the atmosphere. Others think heat could slow soil microbes down, heading off this potential carbon burp.

A team of scientists has now taken an important step toward lowering the uncertainty about the microbes' likely response. The researchers conducted the first tropical soil carbon warming experiment by carting tubes of soil up and down a mountainside and measuring how the soil’s carbon content changed. The research suggests a huge carbon bomb may be waiting to explode, the team said, possibly boosting carbon dioxide in the atmosphere by almost 10% over a century -- an amount that would have severe impacts on life on the planet.

“This experiment adds to our insight as to what could go on in future,” said Jerry Melillo, a biogeochemist at the Marine Biological Laboratory in Woods Hole, Massachusetts, who was not involved in the study. “It’s definitely an important contribution.”

Melillo launched one of the earliest soil warming experiments in 1991, using buried electrical cables to heat soil by 5 degrees Celsius in a Massachusetts forest. He sought to determine whether underground microbes digest dead animals and plants faster when things get hot. Dozens more experiments have since come online. A 2016 analysis of 49 of these experiments estimated that warming soils globally could belch a whopping 55 billion metric tons of carbon by 2050 -- about as much as the expected human-caused emissions from the U.S. over that period.

But all soil warming experiments to date have been done in the temperate and boreal zones, which are cold much of the year. The tropics, where about a third of Earth’s soil carbon resides, are already warm year-round. Some scientists have hypothesized that warming tropical soils might release little additional carbon because microbes' digestive enzymes may function sluggishly at hotter temperatures; others believe tropical microbes will respond similarly to their boreal and temperate counterparts.

Without experimental data, computer simulations come to wildly different conclusions about how much carbon tropical soil microbes will release. Differences in such estimates for this century vary by a greater amount than the total carbon emitted by humans to date, making it hard for bodies like the Intergovernmental Panel on Climate Change, or IPCC, to pin down how much warming to expect. Data from tropical soils, said Melillo, “is absolutely critical.”

To fill this gap, Andrew Nottingham, an ecologist at the University of Edinburgh in the United Kingdom, devised a way to warm soils without expensive, complicated underground infrastructure. In 2010, he and his research team extracted 50-centimeter-long, 10-centimeter-wide cylinders of soil from different heights on a heavily forested mountainside in Peru’s Manu National Park. The environments ranged from steamy Amazon rainforest 200 meters above sea level to high-elevation cloud forest 3,000 meters up the slope. They carted the high-elevation ones down to the bottom (and vice versa) and reburied them. The journeys involved hours of hiking, long bus rides and even a canoe trip down a river.

The approach allowed the researchers to hit the highest-elevation soils with temperatures 15 degrees Celsius (27 degrees Fahrenheit) warmer, on average, than they would normally see.

The researchers also installed filters and funnels to ensure each soil core received the same average rainfall it would have had it not been moved.

Five years later, the research team measured the carbon in each soil core and compared it to the amounts in soils that had not been moved. They also studied variables such as the makeup of bacterial and fungal communities and the activity of the microbial enzymes.

They found that for each 1 degree C (1.8 degrees F) uptick in temperature, soil carbon declined by 4%. They also found evidence that the microbes in the warmed soils produced enzymes that allowed them to decompose plant and animal remains more efficiently. If this pattern holds for soils throughout the tropics, which span much of Latin America, Africa and Asia, atmospheric carbon dioxide could balloon over this century by an additional 9% above what humans and other sources will emit, Nottingham said. Though studies in other sites are needed to verify this prediction, the result suggests tropical soils will see “a very large loss of carbon,” he said. “It’s larger than we expected.”

Nottingham noted that his experiment had limitations: He and his colleagues did not transport plants growing atop their soil cores, which could affect how much carbon microbes have to feast on. And they did not attempt to mimic non-temperature-related conditions of the future.

They also could not heat soils beyond the average temperature of the low-lying forest, about 26 degrees C (79 degrees F). To see how tropical soils might respond to the even higher temperatures expected as the climate warms, Nottingham has installed electrical coils that are heating rainforest soil at a Smithsonian Tropical Research Institute site in Panama. (A separate warming experiment is underway in Puerto Rico, though it was knocked offline for a year by 2017’s Hurricane Maria.)

Kathe Todd-Brown, a soil ecologist at the University of Florida in Gainesville who co-authored the 2016 analysis, praised the researchers for devising a way to produce a big soil carbon change in a short time.

In one sense, she said, the result is “reassuring”: it suggests that climate models that assume tropical soils will behave similarly to temperate and boreal ones -- including many of those used by the IPCC -- do not need to be rewritten.

But the study’s implications for future climate change, said Todd-Brown, are not reassuring.

“Soils will not save us.”

There is hope, however, that with smart management, soil microbes could at least help us. Some scientists believe practices such as reforestation and no-till farming could help restore tropical soils and cause them to sequester carbon instead of release it.

Beyond carbon storage, soil microbes are also critical to biodiversity and forest health, added Norma Salinas, an ecologist at Pontifical Catholic University of Peru in Lima and a member of the research team. “People say the microbiome is important for your health,” she said. “For the ecosystem, it is the same -- if you see very healthy soils, you can see a very good ecosystem.”

Originally published on Inside Science by Gabriel Popkin, Contributor.

The work is published on "early view" in Ecology Letters.

Editor's Note: This story was updated on Oct. 1, 2019 to include additional information about the location of the soil warming experiment in Panama.


Mailing Address

The Ecosystems Center
7 MBL Street
Woods Hole, MA 02543-1015

Physical Address

CV Starr Environmental Laboratory
11 Albatross Street
Woods Hole, MA

Support Us

Support the Ecosystems Center with a gift to the MBL Annual Fund!