Less intensively managed grasslands have higher plant diversity and better soil health, research shows for first time

Study finds an average of 50% more plant species and increased numbers of invertebrates in less managed British grazed grasslands

Peer-Reviewed Publication

UK CENTRE FOR ECOLOGY & HYDROLOGY

 

IMAGE: THE STUDY SHOWS THAT LESS INTENSIVELY MANAGED GRASSLAND HAS GREATER PLANT DIVERSITY. PICTURED ARE COWS FED ON PASTURE IN ARNSIDE, CUMBRIA. view more 

CREDIT: MARKUS WAGNER

Researchers have shown - for the first time - that less intensively managed British grazed grasslands have on average 50% more plant species and better soil health than intensively managed grassland. The new study could help farmers increase both biodiversity and soil health, including the amount of carbon in the soil of the British countryside.

Grazed grassland makes up a large proportion of the British countryside and is vital to farming and rural communities. This land can be perceived as only being about food production, but this study gives more evidence that it could be key to increasing biodiversity and soil health.

Researchers at the UK Centre for Ecology & Hydrology (UKCEH) studied 940 plots of grassland, comparing randomly selected plots which sampled the range of grassland management across Great Britain; from intensively- managed land with a few sown grassland species and high levels of soil phosphorus (indicating ploughing/reseeding and fertiliser and slurry application), to grassland with higher levels of species and lower levels of soil phosphorus. The plots were sampled as part of the UKCEH Countryside Survey, a nationally representative long-term dataset.

The study counted the number of plant species in sample areas and analysed co-located soil samples for numbers of soil invertebrates and carbon, nitrogen and phosphorus levels.

Researchers found that less intensively managed grassland had greater diversity of plant species and, strikingly, this correlated with better soil health, such as increased nitrogen and carbon levels and increased numbers of soil invertebrates such as springtails and mites.

In the same study, the researchers used the same methods to examine the plant diversity and soil from grasslands on 56 mostly beef farms from the Pasture Fed Livestock Association (PFLA) - a farmer group that has developed standards to manage and improve soil and pasture health.

The researchers found that plots of land from PFLA farms had greater plant diversity – on average an additional six plant species, including different types of grasses and herbaceous flowering plants, compared to intensively farmed plots from the Countryside Survey. In addition, grassland plants on these farms were often taller, a quality which is proven to be beneficial to butterflies and bees.

Pasture Fed Livestock Association grasslands did not yet show increased soil health, but the research indicated that this may be due to a time lag between increasing numbers of plant species and changes in soil health, particularly on farms which have been intensively managed in the past.

Lead author Dr Lisa Norton, Senior Scientist at UKCEH, says: “We’ve shown for the first time, on land managed by farmers for production, that a higher diversity of plants in grasslands is correlated with better soil health. This work also tells us that the Pasture Fed Livestock Association members are on the right track to increase biodiversity, though it may take longer to see improvements in soil health.

“Grassland with different types of plants able to grow tall and flower is associated with improved soil health measures, and is beneficial for creepy crawlies below and above ground. Having this abundance of life in our grasslands can in turn support small mammals and birds of prey, and farmers have told us that they are seeing voles and mice in their fields for the first time.”

Dr Norton adds: “My hope for the future is that our grasslands can be managed less intensively – with all the improvements in plant and animal biodiversity and soil health that brings - but still remain productive for farmers.”

The study was published in the journal Ecology Solutions and Evidence on 25 November, 2022, and was funded by the UK Research and Innovation Global Food Security Programme.

-Ends-

Media enquiries

For interviews and further information, please contact:
Simon Williams, Media Relations Officer at UKCEH, via simwil@ceh.ac.uk or +44 (0)7920 295384

Jo Kelly, Campus PR, T: +44 (0)113 258 9880 M: +44 (0)7980 267756 E: jo@campuspr.co.uk 

 

Notes for editors

Paper DOI: 10.1002/2688-8319.12191

After the embargo lifts the paper will be published here: https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12191

In 2020 the UK had the largest numbers of sheep and third largest number of cattle of all EU countries.

 

About the UK Centre for Ecology & Hydrology (UKCEH)

The UK Centre for Ecology & Hydrology is a centre for excellence in environmental science across water, land and air. Our 500-plus scientists seek to understand the environment, how it sustains life and the human impact on it, so that together, people and nature can prosper.

We have a long history of investigating, monitoring and modelling environmental change, and our science makes a positive difference in the world.

www.ceh.ac.uk / Twitter: @UK_CEH / LinkedIn: UK Centre for Ecology & Hydrology

 

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DOI

10.1002/2688-8319.12191 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Can Pasture fed livestock farming practices improve the ecological condition of grassland in Great Britain?

ARTICLE PUBLICATION DATE

25-Nov-2022

Charcoal and cattle correlate with Madagascar’s megafaunal extinctions

Peer-Reviewed Publication

MAX PLANCK INSTITUTE OF GEOANTHROPOLOGY

 

IMAGE: EXCAVATION AT ANKATOKE, NEAR TAMPOLOVE IN SOUTHWEST MADAGASCAR. view more 

CREDIT: GARTH CRIPPS, 2018

The demise of the dodo epitomizes humanity’s record as a destructive force on delicate island life.  Likewise, on the island of Madagascar, gorilla-sized lemurs, 3-meter tall elephant birds, and pygmy hippos went the way of the dodo following the arrival of humans within the last millennia.

But the factors behind the disappearance of these animals are not as well-known as in the case of the dodo, and there is intense debate about what caused the extinction of megafauna the world over.

Now, a new study in Scientific Reports suggests that, while humans had a hand in the extinction of these creatures, hunting alone wasn’t the main cause. While past studies have reported the butchery of endemic animals at least 2,000 years ago, the present study correlates the disappearance of endemic megafauna around 1,000 years ago with a sharp increase in introduced species and human-driven landscape change.

To understand the disappearance of Madagascar’s large animals, Hixon et al. excavated three coastal ponds and a cave from the southwest of the island and radiocarbon dated the remains of extinct megafauna, introduced animals, and other signs of human activity.

The researchers found that Madagascar’s megafauna had endured several dry periods over the last 6,000 years, relocating as needed when local water resources were scarce. Signs of human activity, including modified bones and shells, began appearing within the past 2,000 years.

At around 1,000 years ago, however, the researchers identified a drastic increase in charcoal and the bones of domesticated species, such as zebu cattle and dogs. The timing of these human-caused changes corresponds with the disappearance of megafauna.

 “Our results suggest that occupation and alteration of space, through the burning of forests for introduced grazing species, drove the extinction of large animals on the island, rather than the mere presence of hunters,” says Sean Hixon, lead author of the paper.

In recent years, the debate over the causes of megafauna extinctions have largely focused on past climate change and overhunting by recent human arrivals.  The new study suggests that while both of these may have been stress factors in Madagascar, they weren’t the ultimate cause of megafauna extinctions.

The article underscores that hunting isn’t the only way, or perhaps even the main way, that humans impact other species. In order to protect biodiversity, it is equally important to consider how human activities affect animal habitats and mobility.

The researchers hope that future studies will explore paleontological and archaeological deposits in other areas of the island to form a better understanding of when humans first arrived on Madagascar and how they interacted with their environment.

Extirpated crocodile and extinct pygmy hippo bones excavated from Ankatok in a layer dating to 3,000 - 4,000 years ago

CREDIT

Garth Cripps, 2018

JOURNAL

Scientific Reports

DOI

10.1038/s41598-022-22980-w 

ARTICLE TITLE

Cutmarked Bone of Drought-Tolerant Extinct Megafauna Deposited with Traces of Fire, Human Foraging, and Introduced Animals in SW Madagascar

ARTICLE PUBLICATION DATE

22-Nov-2022

New from JWST: an exoplanet atmosphere as never seen before

Peer-Reviewed Publication

HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

 

IMAGE: NEW OBSERVATIONS OF WASP-39B WITH THE JWST HAVE PROVIDED A CLEARER PICTURE OF THE EXOPLANET, SHOWING THE PRESENCE OF SODIUM, POTASSIUM, WATER, CARBON DIOXIDE, CARBON MONOXIDE AND SULFUR DIOXIDE IN THE PLANET'S ATMOSPHERE. THIS ARTIST'S ILLUSTRATION ALSO DISPLAYS NEWLY DETECTED PATCHES OF CLOUDS SCATTERED ACROSS THE PLANET. view more 

CREDIT: MELISSA WEISS/CENTER FOR ASTROPHYSICS | HARVARD & SMITHSONIAN

Cambridge, Mass. – The JWST just scored another first: a detailed molecular and chemical portrait of a distant world’s skies.

The telescope’s array of highly sensitive instruments was trained on the atmosphere of a “hot Saturn” — a planet about as massive as Saturn orbiting a star some 700 light-years away — known as WASP-39 b. While JWST and other space telescopes, including Hubble and Spitzer, previously have revealed isolated ingredients of this broiling planet’s atmosphere, the new readings provide a full menu of atoms, molecules, and even signs of active chemistry and clouds.

"The clarity of the signals from a number of different molecules in the data is remarkable,” says  Mercedes López-Morales, an astronomer at the Center for Astrophysics | Harvard & Smithsonian and one of the scientists who contributed to the new results. 

“We had predicted that we were going to see many of those signals, but still, when I first saw the data, I was in awe,” López-Morales adds.

The latest data also give a hint of how these clouds in exoplanets might look up close: broken up rather than a single, uniform blanket over the planet.

The findings bode well for the capability of JWST to conduct the broad range of investigations on exoplanets — planets around other stars — scientists hoped for. That includes probing the atmospheres of smaller, rocky planets like those in the TRAPPIST-1 system.

“We observed the exoplanet with multiple instruments that, together, provide a broad swath of the infrared spectrum and a panoply of chemical fingerprints inaccessible until JWST,” said Natalie Batalha, an astronomer at the University of California, Santa Cruz, who contributed to and helped coordinate the new research. “Data like these are a game changer.”

The suite of discoveries is detailed in a set of five newly submitted scientific papers, available on the preprint website arXiv. Among the unprecedented revelations is the first detection in an exoplanet atmosphere of sulfur dioxide, a molecule produced from chemical reactions triggered by high-energy light from the planet’s parent star. On Earth, the protective ozone layer in the upper atmosphere is created in a similar way.

“The surprising detection of sulfur dioxide finally confirms that photochemistry shapes the climate of ‘hot Saturns,’” says Diana Powell, a NASA Hubble fellow, astronomer at the Center for Astrophysics and core member of the team that made the sulfur dioxide discovery. “Earth’s climate is also shaped by photochemistry, so our planet has more in common with ‘hot Saturns’ than we previously knew!”

Jea Adams a graduate student at Harvard and researcher at the Center for Astrophysics analyzed the data that confirmed the sulfur dioxide signal. 

“As an early career researcher in the field of exoplanet atmospheres, it's so exciting to be a part of a detection like this,” Adams says. “The process of analyzing this data felt magical. We saw hints of this feature in early data, but this higher precision instrument revealed the signature of SO2 clearly and helped us solve the puzzle.”

At an estimated temperature of 1,600 degrees Fahrenheit and an atmosphere made mostly of hydrogen, WASP-39 b is not believed to be habitable. The exoplanet has been compared to both Saturn and Jupiter, with a mass similar to Saturn, but an overall size as big as Jupiter. But the new work points the way to finding evidence of potential life on a habitable planet. 

The planet’s proximity to its host star – eight times closer than Mercury is to our Sun – also makes it a laboratory for studying the effects of radiation from host stars on exoplanets. Better knowledge of the star-planet connection should bring a deeper understanding of how these processes create the diversity of planets observed in the galaxy.

Other atmospheric constituents detected by JWST include sodium, potassium, and water vapor, confirming previous space and ground-based telescope observations as well as finding additional water features, at longer wavelengths, that haven’t been seen before.

JWST also saw carbon dioxide at higher resolution, providing twice as much data as reported from its previous observations. Meanwhile, carbon monoxide was detected, but obvious signatures of both methane and hydrogen sulfide were absent from the data. If present, these molecules occur at very low levels, a significant finding for scientists making inventories of exoplanet chemistry in order to better understand the formation and development of these distant worlds.

Capturing such a broad spectrum of WASP-39 b’s atmosphere was a scientific tour de force, as an international team numbering in the hundreds independently analyzed data from four of JWST’s finely calibrated instrument modes. They then made detailed inter-comparisons of their findings, yielding yet more scientifically nuanced results.

JWST views the universe in infrared light, on the red end of the light spectrum beyond what human eyes can see; that allows the telescope to pick up chemical fingerprints that can’t be detected in visible light.

Each of the three instruments even has some version of the “IR” of infrared in its name: NIRSpec, NIRCam, and NIRISS.

To see light from WASP-39 b, JWST tracked the planet as it passed in front of its star, allowing some of the star’s light to filter through the planet’s atmosphere. Different types of chemicals in the atmosphere absorb different colors of the starlight spectrum, so the colors that are missing tell astronomers which molecules are present.

By so precisely parsing an exoplanet atmosphere, the JWST instruments performed well beyond scientists’ expectations — and promise a new phase of exploration among the broad variety of exoplanets in the galaxy.

López-Morales says, "I am looking forward to seeing what we find in the atmospheres of small, terrestrial planets."

 

###

 

 

About the Center for Astrophysics | Harvard & Smithsonian

 

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask—and ultimately answer—humanity’s greatest unresolved questions about the nature of the universe. The Center for Astrophysics is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.

Large parts of Europe are warming twice as fast as the planet on average

Peer-Reviewed Publication

STOCKHOLM UNIVERSITY

 

IMAGE: LEFT AND RIGHT FIGURES SHOW WARMING IN EUROPE OF THE SUMMER HALF YEAR DURING THE LATEST FOUR DECADES, SUBDIVIDED FOR CLEAR-SKY AND ALL.SKY CONDITIONS, RESPECTIVELY. view more 

CREDIT: PAUL GLANTZ/STOCKHOLM UNIVERSITY

The warming during the summer months in Europe has been much faster than the global average, shows a new study by researchers at Stockholm University published in the Journal of Geophysical Research Atmospheres. As a consequence of human emissions of greenhouse gases, the climate across the continent has also become drier, particularly in southern Europe, leading to worse heat waves and an increased risk of fires.

According to the UN's Intergovernmental Panel on Climate Change (IPCC), warming over land areas occurs significantly faster than over oceans, with 1.6 degrees and 0.9 degrees on average, respectively. It means that the global greenhouse gas emissions budget to stay under a 1.5-degree warming on land has already been used up. Now, the new study shows that the emissions budget to avoid a 2-degree warming over large parts of Europe during the summer half-year (April-September) has also been used up. In fact, measurements reveal that the warming during the summer months in large parts of Europe during the last four decades has already surpassed two degrees.

“Climate change is serious as it leads to, among other things, more frequent heat waves in Europe. These, in turn, increase the risk of fires, such as the devastating fires in southern Europe in the summer of 2022,” says Paul Glantz, Associate Professor at the Department of Environmental Science, Stockholm University, and main author of the study.
 
In southern Europe, a clear, so-called, positive feedback caused by global warming is evident, i.e. warming is amplified due to drier soil and decreased evaporation.  Moreover, there has been less cloud coverage over large parts of Europe, probably as a result of less water vapour in the air.

“What we see in southern Europe is in line what IPCC has predicted, which is that an increased human impact on the greenhouse effect would lead to dry areas on Earth becoming even drier,” says Paul Glantz.

Left and right figures show changes in sensible and latent heat fluxes, respectively, in Europe during the latest four decades of the summer half year

Left and right figures show decrease in clouds in Europe during the latest four decades, for the summer half year, with respect to low level clouds and total amount of clouds throughout the atmosphere, respectively.

CREDIT

Paul Glantz/Stockholm University

Impact of aerosol particles

The study also includes a section about the estimated impact of aerosol particles on the temperature increase. According to Paul Glantz, the rapid warming in, for example, Central and Eastern Europe, is first and foremost a consequence of the human emissions of long-lived greenhouse gases, such as carbon dioxide. But since emissions of short-lived aerosol particles from, for example, coal-fired power plants have decreased greatly over the past four decades, the combined effect has led to an extreme temperature increase of over two degrees.

“The airborne aerosol particles, before they began to decrease in the early 1980s in Europe, have masked the warming caused by human greenhouse gases by just over one degree on average for the summer half-year. As the aerosols in the atmosphere decreased, the temperature increased rapidly. Human emissions of carbon dioxide are still the biggest threat as they affect the climate for hundreds to thousands of years,” says Paul Glantz.

According to Paul Glantz, this effect provides a harbinger of future warming in areas where aerosol emissions are high, such as in India and China.

  

Coal power plants on earth emit over 12 Gt of carbon dioxide each year, nearly one third of the total emissions of carbon dioxide. Coal power plants constitute therefore the single largest source of the global warming. Coal power plants emit also sulphur dioxide that forms aerosols in the atmosphere. Coal power plants have decreased and increased substantially in Europe and East Asia, respectively, during the latest four decades.

CREDIT

Tomasz Matuszewski/Mostphotos

CAPTION

Warming and consequently drier conditions in Europe, particularly for southern countries, higher the risk for fires. In the report “Spreading like wildfires: the rising threat of extraordinary landscape fires”, by UN Environmental Program (UNEP) and GRID-Arendal (a UNEP partner) in 2022, conclude that climate change and land-use change are making wildfires worse. The report anticipates a global increase of extreme fires, even in areas previously unaffected. https://www.unep.org/resources/report/spreading-wildfire-rising-threat-extraordinary-landscape-fires

CREDIT

Ryhor Bruyeu/Mostphotos

Background facts - The greenhouse effect and aerosol effect

Fossil burning leads to the release of both aerosol particles and greenhouse gases. Although their source is common, their effects on climate differ.

About the greenhouse effect
Greenhouse gases are largely unaffected by solar radiation while they absorb infrared radiation efficiently, leading to re-emission towards the Earth's surface. The Earth absorbs both solar radiation and infrared radiation, which leads to the warming of the lower part of the atmosphere in particular.

Time-space: Greenhouse gases are generally long-lived in the atmosphere and this applies above all to carbon dioxide where human emissions affect climate for hundreds to thousands of years. It also means that greenhouse gases spread evenly over the entire planet.

About the aerosol effect
In contrast to greenhouse gases, aerosol particles affect incoming solar radiation, i.e. they scatter part of the sunlight back into space causing a cooling effect. Human emissions of aerosols can enhance this cooling effect.

Time-space: Airborne human aerosol particles have a lifetime of about a week, which means that they mainly cool the climate locally or regionally and in the short term.

According to the Paris Agreement, all parties must commit to drastically reduce their greenhouse gas emissions, but it is also important to decrease concentrations of aerosol particles as well because, in addition to their effects on climate, aerosol particles in polluted air cause approximately eight million premature deaths each year around the world.

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JOURNAL

Journal of Geophysical Research Atmospheres

DOI

10.1029/2021JD035889 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Unmasking the effects of aerosols on greenhouse warming over Europe

ARTICLE PUBLICATION DATE

22-Nov-2022

Building green energy facilities may produce substantial carbon emissions, says study

But speeding the transition might nearly cancel the effect

Peer-Reviewed Publication

COLUMBIA CLIMATE SCHOOL

 

IMAGE: A NEW STUDY SUGGESTS THAT BUILDING INFRASTRUCTURE FOR CLEANER ENERGY GENERATION WILL BY ITSELF CREATE CARBON EMISSIONS, BUT THE FASTER IT HAPPENS, THE FEWER THEY WILL BE. view more 

CREDIT: ILLUSTRATION BY JULIE MORVANT-MORTREUIL

First, the bad news: Nothing is free. Moving the world energy system away from fossil fuels and into renewable sources will generate carbon emissions by itself, as construction of wind turbines, solar panels and other new infrastructure consumes energy—some of it necessarily coming from the fossil fuels we are trying to get rid of. The good news: If this infrastructure can be put on line quickly, those emissions would dramatically decrease, because far more renewable energy early on will mean far less fossil fuel needed to power the changeover.

This is the conclusion of a study that for the first time estimates the cost of a green transition not in dollars, but in greenhouse gases. The study appears this week in the Proceedings of the National Academy of Sciences.

“The message is that it is going to take energy to rebuild the global energy system, and we need to account for that,” said lead author Corey Lesk, who did the research as a Ph.D. student at the Columbia Climate School’s Lamont-Doherty Earth Observatory. “Any way you do it, it’s not negligible. But the more you can initially bring on renewables, the more you can power the transition with renewables.”

The researchers calculated the possible emissions produced by energy use in mining, manufacturing, transport, construction and other activities needed to create massive farms of solar panels and wind turbines, along with more limited infrastructure for geothermal and other energy sources. Previous research has projected the cost of new energy infrastructure in dollars—$3.5 trillion a year every year until 2050 to reach net-zero emissions, according to one study, or up to about $14 trillion for the United States alone in the same period, according to another. The new study appears to be the first to project the cost in greenhouse gases.

On the current slow pace of renewable infrastructure production (predicted to lead to 2.7 degrees C warming by the end of the century), the researchers estimate these activities will produce 185 billion tons of carbon dioxide by 2100. This alone is equivalent to five or six years of current global emissions—a hefty added burden on the atmosphere. However, if the world builds the same infrastructure fast enough to limit warming to 2 degrees—current international agreement aims to come in under this—those emissions would be halved to 95 billion tons. And, if a truly ambitious path were followed, limiting warming to 1.5 degrees, the cost would be only 20 billion tons by 2100—just six months or so of current global emissions.

The researchers point out that all their estimates are probably quite low. For one, they do not account for materials and construction needed for new electric-transmission lines, nor batteries for storage—both highly energy- and resource-intensive products. Nor do they include the cost of replacing gas- and diesel- powered vehicles with electric ones, or making existing buildings more energy efficient. The study also looks only at carbon-dioxide emissions, which currently cause about 60 percent of ongoing warming—not other greenhouse gases including methane and nitrous oxide.

Other effects of the move to renewables are hard to quantify, but could be substantial. All this new high-tech hardware will require not just massive amounts of base metals including copper, iron and nickel, but previously lesser-used rare elements such as lithium, cobalt, yttrium and neodymium. Many commodities would probably have to come from previously untouched places with fragile environments, including the deep sea, African rain forests and fast-melting Greenland. Solar panels and wind turbines would directly consume large stretches of land, with attendant potential effects on ecosystems and people living there.

“We’re laying out the bottom bound,” said Lesk of the study’s estimates. “The upper bound could be much higher.” But, he says, “the result is encouraging.” Lesk said that given recent price drops for renewable technologies, 80 to 90 percent of what the world needs could be installed in the next few decades, especially if current subsidies for fossil-fuel production are diverted to renewables. “If we get on a more ambitious path, this whole problem goes away. It’s only bad news if we don’t start investing in the next 5 to 10 years.”

As part of the study, Lesk and his colleagues also looked at carbon emissions from adapting to sea-level rise; they found that construction of sea walls and moving cities inland where necessary would generate 1 billion tons of carbon dioxide by 2100 under the 2-degree scenario. This, again, would be only part of the cost of adaptation; they did not look at infrastructure to control inland flooding, irrigation in areas that might become drier, adapting buildings to higher temperatures or other needed projects.

“Despite these limitations, we conclude that the magnitude of CO2 emissions embedded in the broader climate transition are of geophysical and policy relevance,” the authors write. “Transition emissions can be greatly reduced under faster-paced decarbonization, lending new urgency to policy progress on rapid renewable energy deployment.”

The other authors of the study are Denes Csala of the United Kingdom’s University of Lancaster; Robin Krekeler and Antoine Levesque of Germany’s Potsdam Institute for Climate Impacts Research; Sgouris Sgouridis of the Dubai Electricity and Water Authority; Katharine Mach of the University of Miami; Daniel Horen Greenford and H. Damon Matthews of Canada’s Concordia University; and Radley Horton of Lamont-Doherty Earth Observatory. Corey Lesk is now a postdoctoral researcher at Dartmouth College.

Mining for raw materials, transport, manufacturing and construction are all energy-intensive. Here, a mining vehicle at an open-cast mine in Canada’s Northwest Territories.

CREDIT

Kevin Krajick/Earth Institute

Rare commodities newly in demand for green technologies such as lithium, yttrium and neodymium will have to come from new sources. These include fast-melting Greenland (its southeast coast, above), which is rich in these substances.

CREDIT

Margie Turrin/Lamont-Doherty Earth Observatory

Lead author contact:

Corey Lesk  lesk@ldeo.columbia.edu

The Columbia Climate School develops innovative education, supports groundbreaking research and fosters essential solutions, from the community to the planetary scale.  https://climate.columbia.edu/

Lamont-Doherty Earth Observatory develops fundamental knowledge about the origin, evolution and future of the natural world, from the planet’s deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean.
www.ldeo.columbia.edu  |  @LamontEarth

 

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JOURNAL

Proceedings of the National Academy of Sciences

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Mitigation and Adaptation Emissions Embedded in the Broader Climate Transition

ARTICLE PUBLICATION DATE

21-Nov-2022

IPK researchers identify last remaining steps in the biosynthesis of tropane alkaloids from Coca

Peer-Reviewed Publication

LEIBNIZ INSTITUTE OF PLANT GENETICS AND CROP PLANT RESEARCH

 

IMAGE: PICTURED IS A FLOWER FROM THE COCA PLANT, ERYTHROXYLUM COCA LAM. BENJAMIN CHAVEZ AND COLLEAGUES USED A YEAST BASED SYNTHETIC BIOLOGY PLATFORM TO ELUCIDATE THE LAST REMAINING ENZYMATIC STEPS INVOLVED IN TROPANE ALKALOID FORMATION IN ERYTHROXYLUM COCA. THEIR FINDINGS REVEALED A NEARLY COMPLETE INDEPENDENT ORIGIN HAS EVOLVED WHEN COMPARED TO THE SOLANACEOUS PATHWAY. view more 

CREDIT: DANNY KESSLER

Tropane alkaloids are a particular class of plant derived compounds that have been exploited by mankind since the domestication of medicinal plants. The distribution of these alkaloids is scattered amongst the flowering plants and the two most studied families include those from the Solanaceae (tomato, tobacco, potato relatives) and the Erythroxylaceae (coca). The WHO lists several tropane alkaloids as some of the most important medicines in the modern day pharmacopeia. However other compounds such as cocaine are more infamous for their narcotic and euphorigenic properties. “It is critical to understand how plants produce these alkaloids in order for mankind to continue to build upon nature and develop new useful medicines”, says Dr. John D’ Auria, head of the IPK’s research group “Metabolic Diversity”.

The most studied and characterized system for tropane production has historically been within Solanaceae. There are more than ten chemical modification steps necessary to transform the beginning amino acid precursors into the final active alkaloids and all of these steps were identified and characterized in solanaceous plants. The scattered distribution of tropanes among flowering plants has always hinted that different families may have developed the ability to produce these alkaloids independently from one another. In fact, several steps of tropane biosynthesis were already documented to have evolved independently within members of the Erythroxylaceae.

“We have been working on elucidating the coca derived tropane pathway for the last 15 years and we have been successful in working on several key steps in the biosynthesis of cocaine and other related tropanes in coca”, says the IPK researcher. “The idea that coca would share similar enzymes and genes with their distant solanaceous relatives was incorrect. While the final structure of tropanes is similar, the pathway leading to these alkaloids is different.” 

In order to discover the last remaining steps of the pathway in coca, Dr. John D’ Auria collaborated with the lab of Dr. Christina Smolke from Stanford University. The Smolke group are experts at manipulating yeast and microorganisms to produce important medicinal compounds via synthetic biology methods. “With their assistance, we used the multiplicative power of gene manipulation in yeast to test many different gene candidates for the missing steps in the coca pathway. In essence, at every unknown step, we designed and tested multiple candidate sequences.” These candidate sequences originated from transcriptome studies performed Dr. John D’ Auria’s group as well as the group of Dr. Lyndel Meinhardt from the USDA in Beltsville, Maryland (USA). “Using this powerful gene discovery platform, we successfully identified all the remaining ‘missing steps’ for tropane biosynthesis in coca. This represents the culmination of more than ten graduate student projects in my group and 15 years of my research”, says Dr. John D’ Auria. 

The most significant portions of the findings now confirms that tropane biosynthesis has independently evolved at least twice during the evolution of flowering plants. “This is important because we also show in our study that you can mix and match the Solanaceae and Erythroxylaceae genes and produce tropanes”, says the IPK reseracher. In layman’s terms, the research provides multiple tools for synthetic biologists to begin designing the tropane alkaloid pathway in organisms that have never produced them before, and with the ability to use different enzymes for similar steps, it is possible to optimize or modify those steps for specific chemical outcomes.

“In addition, we also show that the beginning portion of the pathway in coca proceeds by an interesting ‘detour’ or alternate route that doesn’t exist in solanaceous species”, says Benjamin Chavez, the first author of the study and a PhD student in the D’Auria laboratory. “This provides insights in how plant metabolism can find solutions to biochemical challenges. Namely, we can understand the interplay between early precursors and their bottlenecks.”

Lastly, the researchers discovered a specific enzyme that is responsible for the so called ‘carbomethoxy group’ present exclusively in coca alkaloids. Solanaceous species do not have this modification. The carbomethoxy group is partially responsible for the euphorigenic properties of cocaine.

 

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2215372119 

ARTICLE TITLE

Elucidation of tropane alkaloid biosynthesis in Erythroxylum coca using a microbial pathway discovery platform

ARTICLE PUBLICATION DATE

21-Nov-2022