It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, June 15, 2021
Introducing play to higher education reduces stress and forms deeper connection material
Students fostered a more meaningful relationship with instructors when play was introduced
A new study found higher education students are more engaged and motivated when they are taught using playful pedagogy rather than the traditional lecture-based method. The study was conducted by University of Colorado Denver counseling researcher Lisa Forbes and was published in the Journal of Teaching and Learning.
While many educators in higher education believe play is a method that is solely used for elementary education, Forbes argues that play is important in post-secondary education to enhance student learning outcomes.
Throughout the spring 2020 semester, Forbes observed students who were enrolled in three of her courses between the ages of 23-43. To introduce playful pedagogy, Forbes included games and play, not always tied to the content of that day's lesson, at the start of each class. She then provided many opportunities for role-play to practice counseling skills, and designed competitions within class activities.
During the study, students mentioned they saw more opportunities for growth while learning in a highly interactive environment. Students also described that the hands-on nature of learning through play established a means for skill acquisition, and they were able to retain the content more effectively.
"As we grow older, we're conditioned to believe that play is trivial, childish, and a waste of time," said Forbes. "This social script about play leads to it being excluded from higher education. A more interactive learning approach leads to a deeper and more rigorous connection to the material."
To maintain what Forbes described as "rigor" within higher education, the most common approach tends to be lecture-based learning. However, according to Forbes, this mode of education is counter to the very outcomes educators set out to achieve.
The results of the study suggest there is a unique and powerful classroom experience when play is valued and used in the learning process. According to Forbes, students who participated in this study also indicated that play increased positive emotions and connections with other students and the professor in the course.
"I also saw that when I introduced play, it helped students let their guard down and allowed them to reduce their stress, fear, or anxiety," said Forbes. "Play even motivated students to be vulnerably engaged, take risks, and feel more connected to the content."
Play is underutilized and devalued in higher education, according to Forbes. She suggests educators reevaluate their understanding of using play in graduate courses. Playful pedagogy creates an interactive and warm learning environment, resulting in greater understanding of the material. This method is also more aligned with the humanistic missions and values of universities and programs.
Homo Ludens is a book originally published in Dutch in 1938 by Dutch historian and cultural theorist Johan Huizinga. It discusses the importance of the play element of culture and society. Huizinga suggests that play is primary to and a necessary (though not sufficient) condition of the generation of culture. The Latin word ludens is the present active participle of the verb ludere, which itself is …
Reception
Foreword controversy
Contents
Quotations
Editions
See also
Notes
Homo Ludens is an important part of the history of game studies. It influenced later scholars of play, like Roger Caillois. The concept of the magic circle was inspired by Homo Ludens.
UNDERPAID, UNDERAPPRECIATED AMERICAN TEACHERS
Job-related stress threatens the teacher supply - RAND survey
Nearly one in four teachers may leave their job by the end of the current (2020-'21) school year, compared with one in six who were likely to leave prior to the pandemic, according to a new RAND Corporation survey. Teachers who identified as Black or African American were particularly likely to consider leaving.
U.S. public-school teachers surveyed in January and February 2021 reported they are almost twice as likely to experience frequent job-related stress as the general employed adult population and almost three times as likely to experience depressive symptoms as the general adult population.
These results suggest potential immediate and long-term threats to the teacher supply.
"Teacher stress was a concern prior to the pandemic and may have only become worse. The experiences of teachers who were considering leaving at the time of our survey were similar in many ways to those of teachers who left the profession because of the pandemic," said Elizabeth Steiner, lead author of the report and a policy researcher at RAND, a nonprofit, nonpartisan research organization. "This raises the concern that more teachers may decide to quit this year than in past years if nothing is done to address challenging working conditions and support teacher well-being."
Stressful working conditions included a mismatch between actual and preferred mode of instruction, lack of administrator and technical support, frequent technical issues with remote teaching, and lack of implementation of COVID-19 safety measures. Stressors relating to mode of instruction and health were ranked most highly by teachers surveyed.
About a third of teachers were responsible for the care and learning support of their own children while teaching. These stressful working conditions were even more prevalent among teachers who were likely to quit after the onset of the pandemic, but not before.
"Given that some pandemic-era stressors, such as remote teaching, might be here to stay, we think district and school leaders can support teachers' well-being by understanding current working conditions and their need for a more supportive and flexible work environment," said Ashley Woo, coauthor and an assistant policy researcher at RAND.
The report recommends schools implement COVID-19 mitigation measures in a way that allows teachers to focus on instruction and offset worries about their health. Schools and districts should consider systematically collecting data about the mental health and well-being needs of teachers to understand the sources of teacher distress in their school communities while also working together to design and implement mental health and wellness supports. Helping teachers access childcare could go a long way to alleviating stress and promoting teacher retention, as would developing clear policies for remote teaching and adopting technology standards for remote teaching equipment.
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The survey was conducted using the RAND American Educator Panels, nationally representative samples of educators who provide their feedback on important issues of educational policy and practice.
"Job-Related Stress Threatens the Teacher Supply: Key Findings from the 2021 State of the U.S. Teacher Survey" was supported by the National Education Association and the American Federation of Teachers.
RAND Education and Labor, a division of RAND, is dedicated to improving education and expanding economic opportunities for all through research and analysis. Its researchers address key policy issues in U.S. and international education systems and labor markets, from pre-kindergarten to retirement planning.
IMAGE: ARTISTIC REPRESENTATION OF GUNGGAMARANDU MAUNALA. view more
CREDIT: ELEANOR PEASE
A new species of large prehistoric croc that roamed south-east Queensland's waterways millions of years ago has been documented by University of Queensland researchers.
PhD candidate Jorgo Ristevski, from UQ's School of Biological Sciences, led the team that named the species Gunggamarandu maunala after analysing a partial skull unearthed in the Darling Downs in the nineteenth century.
"This is one of the largest crocs to have ever inhabited Australia," Mr Ristevski said.
"At the moment it's difficult to estimate the exact overall size of Gunggamarandu since all we have is the back of the skull - but it was big.
"We estimate the skull would have been at least 80 centimetres long, and based on comparisons with living crocs, this indicates a total body length of around seven metres.
"This suggests Gunggamarandu maunala was on par with the largest Indo-Pacific crocs - a Crocodylus porosus) - recorded.
"We also had the skull CT-scanned, and from that we were able to digitally reconstruct the brain cavity, which helped us unravel additional details about its anatomy.
"The exact age of the fossil is uncertain, but it's probably between two and five million years old."
Gunggamarandu belonged to a group of crocodylians called tomistomines or 'false gharials'.
"Today, there's only one living species of tomistomine, Tomistoma schlegelii, which is restricted to the Malay Peninsula and parts of Indonesia," Mr Ristevski said.
"With the exception of Antarctica, Australia was the only other continent without fossil evidence of tomistomines.
"But with the discovery of Gunggamarandu we can add Australia to the 'once inhabited by tomistomines' list."
Despite its discovery, the fossil skull of Gunggamarandu maunala remained a scientific mystery for more than a century.
The specimen piqued the interest of then-young graduate student Dr Steve Salisbury in the 1990s, but a formal study was not done until Mr Ristevski began his examination.
"I knew it was unusual, and potentially very significant, but I didn't have the time to study it in any detail," Dr Salisbury said.
"The name of the new species honours the First Nations peoples of the Darling Downs area, incorporating words from the languages of the Barunggam and Waka Waka nations.
"The genus name, Gunggamarandu, means 'river boss', while the species name, maunala, means 'hole head'.
"The latter is in reference to the large, hole-like openings located on top of the animal's skull that served as a place for muscle attachment."
The research has been published in the open access journal Nature Scientific Reports (DOI: 10.1002/spp2.1296).
CAPTION
Hypothetical outline of the skull of Gunggamarandu maunala, with the fossil skull piece depicted in its corresponding position, compared with a 1.8m tall human.
CREDIT
Jorgo Ristevski
Early migrations of Siberians to America tracked using bacterial population structures
Early migrations of humans to the Americas from Siberia around 12,000 years ago have been traced using the bacteria they carried by an international team including scientists at the University of Warwick
International team used the stomach bacteria Helicobacter pylori as a biomarker for ancient human migrations
DNA sequences catalogued at University of Warwick in EnteroBase, a public genomes database, demonstrate that a migration of Siberians to the Americas occurred approximately 12,000 years ago
Project began in 2000s but new statistical techniques allowed researchers to reconstruct and date the migrations of Siberian Helicobacter pylori
Early migrations of humans to the Americas from Siberia around 12,000 years ago have been traced using the bacteria they carried by an international team including scientists at the University of Warwick.
Using samples of a stomach bacteria called Helicobacter pylori, which has shared a tight co-evolutionary relationship with humans for at least the past 100,000 years, analyses using new statistical techniques provide evidence that humans colonised the Americas through a pre-Holocene migration of evolutionarily ancient northern Eurasians across the Bering land bridge.
The study entitled "Helicobacter pylori's historical journey through Siberia and the Americas" is published this week (14 June) in the prestigious international journal Proceedings of the National Academy of Sciences of the USA (PNAS) by a team of researchers led by Professor Yoshan Moodley at the University of Venda, South Africa.
The research used genetic information on H. pylori catalogued in EnteroBase at the University of Warwick to trace the evolutionary history of the bacteria. H. pylori is a stomach bacteria that infects approximately half of individuals worldwide, but scientists have found that its genetic sequence also varies with the region that it is identified in.
Previous analyses had identified three populations of H. pylori from individuals in Eurasia and the Americas, and current data demonstrates that H. pylori from Siberia define additional previously unknown subpopulations of those groupings. The data also indicated one of these bacterial populations, which includes H. pylori from indigenous Americans, was distributed over the breadth of Siberia, suggesting that this population may have travelled with humans to the Americas at some point.
However, classical statistical analyses of the sequences were partially inconsistent with each other. To reconstruct the most likely evolutionary history for H. pylori in Siberia, researchers compared the most likely evolutionary models and timings using a technique called approximate Bayesian computation (ABC). The results showed that a tiny population of H. pylori colonised the Americas in a single migration event approximately 12,000 years ago.
Professor Mark Achtman of Warwick Medical School at the University of Warwick, senior co-author on the paper, said: "This project began in the early 2000s, when nothing was known about the genetic diversity of Helicobacter pylori in central Asia. By 2007, hundreds of Siberian H. pylori strains had been cultivated and selected genes had been sequenced. But repeated attempts by multiple talented population geneticists failed to shed light on their evolutionary history.
"This study now uses the powerful approach of ABC statistics to reconstruct and date the migrations of Siberian H. pylori (and their human hosts) across Siberia and to the Americas."
Originally, all modern humans came from Africa. About 60,000 years ago small groups of hunter-gatherers left Africa on foot and made their way into Eurasia where they settled. These were the world's first human immigrants. Astonishingly, by the end of the ice age some 50,000 years later, modern humans had already reached the American continent which, if travelling over land, is almost as far away from Africa as it is possible to get.
These ancient human migrations took place during the last glacial period, or ice age, which lasted from 115,000 to 11,700 years ago. At that time, most of northern Eurasia, also known as Siberia, would have been a frozen wasteland, and presumably inhospitable to long-term human settlement. So how then, did humans manage to migrate across this vast region and find their way to North America? This is one of the most important, and as yet unanswered, questions in human prehistory, because it would explain how humans were able to colonise the whole world from an African origin, in such a short space of time.
The team took the unusual approach of using the DNA of a human stomach bacterium named Helicobacter pylori as a biomarker for ancient human migrations. They successfully collected, sequenced and analysed bacterial strains from indigenous people across Siberia and the Americas. The bacterial DNA sequence database they generated suggested that, remarkably, some groups of humans, known as ancient northern Eurasians, did manage to reside in Siberia throughout the bitter ice age. Yet, other human groups who originally inhabited warmer latitudes in Asia, colonised Siberia after the end of the ice age, leading to the complex mix of human populations we see in that region today.
The team also used their bacterial data set to model human migration into the Americas. It is important to remember that during the ice age, much more water was frozen at the earth's poles, making the sea level at that time over 100 metres lower than the present-day sea level, thus exposing a land bridge between Eurasia and North America and allowing human migration. The team showed that one small group of ancient northern Eurasians managed to successfully cross this land bridge about 12,000 years ago, and this population subsequently expanded to give rise to the indigenous Americans we see today.
Study finds lightning impacts edge of space in ways not previously observed
Solar flares jetting out from the sun and thunderstorms generated on Earth impact the planet's ionosphere in different ways, which have implications for the ability to conduct long range communications
Solar flares jetting out from the sun and thunderstorms generated on Earth impact the planet's ionosphere in different ways, which have implications for the ability to conduct long range communications.
A team of researchers working with data collected by the Incoherent Scatter Radar (ISR) at the Arecibo Observatory, satellites, and lightning detectors in Puerto Rico have for the first time examined the simultaneous impacts of thunderstorms and solar flares on the ionospheric D-region (often referred to as the edge of space).
In the first of its kind analysis, the team determined that solar flares and lightning from thunderstorms trigger unique changes to that edge of space, which is used for long-range communications such the GPS found in vehicles and airplanes.
The work, led by New Mexico Tech assistant professor of physics Caitano L. da Silva was published recently in the journal Scientific Reports, a journal of the Nature Publishing Group.
"These are really exciting results," says da Silva. "One of the key things we showed in the paper is that lightning- and solar flare-driven signatures are completely different. The first tends to create electron density depletions, while the second enhancements (or ionization)."
While the AO radar used in the study is no longer available because of the collapse of AO's telescope in December of 2020, scientists believe that the data they collected and other AO historical data will be instrumental in advancing this work.
"This study helps emphasize that, in order to fully understand the coupling of atmospheric regions, energy input from below (from thunderstorms) into the lower ionosphere needs to be properly accounted for," da Silva says. "The wealth of data collected at AO over the years will be a transformative tool to quantify the effects of lightning in the lower ionosphere."
Better understanding the impact on the Earth's ionosphere will help improve communications.
da Silva worked with a team of researchers at the Arecibo Observatory (AO) in Puerto Rico, a National Science Foundation facility managed by the University of Central Florida under a cooperative agreement. The co-authors are AO Senior Scientist Pedrina Terra, Assistant Director of Science Operations Christiano G. M. Brum and Sophia D. Salazar a student at NMT who spent her 2019 summer at the AO as part of the NSF- supported Research Undergraduate Experience. Salazar completed the initial analysis of the data as part of her internship with the senior scientists' supervision.
"The Arecibo Observatory REU is hands down one of the best experiences I've had so far," says the 21-year-old. "The support and encouragement provided by the AO staff and REU students made the research experience everything that it was. There were many opportunities to network with scientists at AO from all over the world, many of which I would likely never have met without the AO REU."
AO's Terra and Brum worked with Salazar taking her initial data analysis, refining it and providing interpretation for the study.
"Sophia's dedication and her ability to solve problems grabbed our attention from the very first day of the REU program," Brum says. "Her efforts in developing this project resulted in publication in one of the most prestigious journals in our field."
"Another remarkable result of this work is that for the first time, a mapping of the spatial and seasonal occurrence of lightning strike over the region of the Puerto Rico archipelago is presented," Brum says. "Intriguing was also the detection of a lighting activity hotspot concentrated in the western part of La Cordillera Central mountain range of Puerto Rico."
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About the authors:
da Silva conducts research in the area of atmospheric sciences, geophysics, and plasma physics. He's intrigued by space electricity; thunderstorms and their effects in the near-Earth space environment; lightning physics; modeling of electrical discharge plasmas; and development of computer-based tools for analysis of atmospheric and geophysical phenomena. He holds multiple degrees including a doctorate in electrical engineering from Penn State University and a master's degree in geophysics and space physics from the National Institute for Space Research (INPE) in Brazil, which is the same alma mater of Brum and Terra. The three INPE alumni had a brief brainstorming session over coffee about this project in the AGU 2018 Fall Meeting, in San Francisco, CA.
Terra who worked at AO since 2006, was a post-doctoral scholar at Cornell University. She has multiple degrees including an electrical engineering degree and both master's and doctorate in space physics from the INPE Research in Brazil. Terra is a UCF's graduate faculty member and is the responsible for the passive optical laboratories at AO, including the remote facility at the island of Culebra.
Brum has been working at AO since 2007 and was a post-doctoral scholar at INPE, Utah State University, and Cornell University. He holds multiple degrees including a master's and a doctorate degree in space geophysics from the INPE. Brum is the head of the AO Space and Atmospheric department, Deputy Director of Science Operations, and a UCF graduate faculty member.
Eco-friendly smart farms based on nutrient solution recirculation
UV sterilization and microbial stability analysis used to recycle nutrient solution; proposed method minimizes the use fertilizers and water by hydroponic farms
IMAGE: THE INTEGRATED MODEL DESCRIPTION. view more
CREDIT: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY(KIST)
The development of new urban agriculture technologies, such as vertical and smart farms, has accelerated rapidly in recent years. These technologies are based on hydroponic cultivation in which plants are grown using nutrient-rich solutions rather than soil. Approximately 20-30% of the nutrient solutions used during hydroponic cultivation are discharged without being absorbed by the crops, and because most farmers in South Korea do not treat the discharged solutions, hydroponic farms contribute significantly to environmental pollution.
This problem can be reduced if hydroponic farms use a recirculating hydroponic cultivation method that reuses the nutrient solutions after sterilizing them with ultraviolet (UV) light, instead of discharging them. However, two main issues complicate the implantation of such recirculation systems. First, the potential for diseases and nutrient imbalances to develop owing to microbial growth in the recycled nutrient solutions must be eliminated. Second, the initial investment required to set up a recirculating hydroponic cultivation system is often prohibitive, costing hundreds of millions of Korean won per hectare.
However, a new study conducted by researchers at the Korea Institute of Science and Technology (KIST)proposes a method that can stably manage the microbial population in recirculating hydroponic cultivation systems. The research team, led by Drs. Ju Young Lee and Tae In Ahn of the Smart Farm Research Center, KIST Gangneung Institute of Natural Products, conducted an integrated analysis of the microbial growth characteristics by constructing a model that simulates the flow of water and nutrients, and the inflow, growth, and discharge of microorganisms in recirculating and non-circulating hydroponic cultivation systems. Their simulations revealed that the microbial population in recirculating hydroponic cultivation systems can be controlled by adjusting the UV output and the water supply. On the contrary, in non-circulating hydroponic cultivation, the microbial population fluctuates considerably depending on the amount of water used, increasingly sharply if there is too little water.
High cost has restricted the use of UV sterilization systems in hydroponic farming in Korea And prompted the research team to develop their own UV sterilization system, with further studies underway to commercialize this system as an economical alternative to imported systems.
The results of the study have already received strong interest: the rights to the operation and management software technology for recirculating hydroponic cultivation has been acquired by Dooinbiotech Co., Ltd. for an advance fee of 80 million won (8.5% of the operating revenue), while an agreement is in place with Shinhan A-Tec Co., Ltd. for the advanced recirculating hydroponic cultivation technology for an advance fee of 200 million won (1.5% of the operating revenue). Commercializing the recirculating hydroponic cultivation system is expected to reduce fertilizer costs by approximately 30~40%, which equates to 30 million won per year based on a 1-hectare farm.
Commenting on the envisaged impacts of the study, Dr. Ju Young Lee said, "The developed system makes the transition to eco-friendly recirculating hydroponic cultivation systems an affordable option for many more farmers." Dr. Tae In Ahn added, "We are also developing software and operation manuals to guide farmers in managing the nutrient balance in the solutions to increase the number of farms using the recirculating hydroponic cultivation system."
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The study was supported by the Ministry of Agriculture, Food, and Rural Affairs (Institute of Planning and Evaluation for Technology in Food, Agriculture, and Forestry) and the Innovative Smart Farm Technology Development Program of Multi-agency Package. The research results are published in the latest issue of the Journal of Cleaner Production (IF: 7.24, ranked in the top 6.9% by JCR), a highly respected international journal in the field of environmental science.
Human-driven climate change only half the picture for krill
IMAGE: ANTARCTIC KRILL, EUPHAUSIA SUPERBA. view more
CREDIT: UWE KILS / WIKIPEDIA
In the heart of their Antarctic habitat, krill populations are projected to decline about 30% this century due to widespread negative effects from human-driven climate change. However, these effects on this small but significant species will be largely indistinguishable from natural variability in the region's climate until late in the 21st century, finds new University of Colorado Boulder research.
Published today in Frontiers in Marine Science, the study has important implications for not only the local food web, but for the largest commercial fishery in the Southern Ocean: A booming $2 billion fish oil industry, sold as Omega-3 supplements in retail giants like Costco.
"Krill are what links the ecosystem together," said Zephyr Sylvester, lead author on the paper and graduate student in environmental studies. "They're really important to the Southern Ocean for pretty much every predator species."
Because these tiny animals live in one of the most sensitive areas in the world to climate change, explicitly separating trends associated with human-driven warming from those arising naturally in krill habitat is a crucial step for planning and mapping harvest limits.
This study is also the first of its kind to use a group of climate models to demonstrate that climate change has the potential to dramatically alter Antarctic marine ecosystems, but that natural climate variability can obscure human-driven trends.
Small but significant
Krill are about 2.5 inches (6 cm) long, fast swimming zooplankton that live in large groups. They're key to the region's food chain, eaten by just about everything that lives in the waters surrounding Antarctica: Penguins, seals, fish and whales, some of which are still recovering from overharvesting in previous centuries.
But while they are one of the most abundant species on Earth--their total biomass estimated at 300 to 500 million tons--krill can only survive in a narrow temperature range and are strongly affected by variables in their underwater environment.
Currently, fishing in the Southern Ocean is managed by the Convention on the Conservation of Antarctic Marine Living Resources, known as CCAMLR (pronounced "cam-ah-lar"), an international body established as part of the Antarctic Treaty System.
The first item on their agenda? Krill. Yet 40 years after their founding, their catch limits on this creature are still only set using a stock assessment that does not account for natural environmental variability or climate change impacts.
While today there is widespread international recognition of the importance of understanding the impacts of climate change on this marine ecosystem, knowing how the climate naturally varies is an important prerequisite, according to Sylvester.
"The thing that we really have to understand is: Is there enough krill to feed everything that needs to eat it in the Southern Ocean, as well as humans?" said Cassandra Brooks, co-author on the paper and assistant professor of environmental studies. "My hope is that we can take this as a first step to understanding how to manage krill better."
What is natural variability?
Every environment on Earth naturally varies a bit each year in its weather, temperature and precipitation. For example, some winters in Colorado have more snowfall, some have less. Some will be a bit warmer, some colder. Human-driven climate change aside, each year in the state has a unique pattern of precipitation and temperature due to natural variability.
But separating the effects of human-driven climate change from natural changes in a region is no easy task. To be able to pull apart the variables affecting the Southern Ocean over this century, the researchers ran a larger group of models many times, known as a large ensemble earth system model. It's the first time this has been done for the Southern Ocean and for krill.
"Then we were able to look at the different trends and quantify how much the natural variability was masking the signal for climate change," said Sylvester.
This research addresses one of the biggest disconnects between scientists and fishery managers: understanding and communicating uncertainty. By being able to quantify how much change is likely to occur from natural variability, and separately from climate change, it allows everyone involved to plan better for the future and sustain krill for those who depend on it, according to Brooks.
"Even if we won't see this really strong signal from climate change until later, what's important for us to understand is that the Southern Ocean is a very dynamic system and we absolutely have to be managing for natural variability," said Brooks. "And we should be ready to manage for the broader impacts of climate change."
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Matthew Long at the National Center for Atmospheric Research is a co-author on this publication.
Microbes in ocean play important role in moderating Earth's temperature
Methane-eating microbes help regulate Earth's temperatures with remarkably high metabolic rates within seafloor carbonate rocks
HARVARD UNIVERSITY, DEPARTMENT OF ORGANISMIC AND EVOLUTIONARY BIOLOGY
IMAGE: TWO VIEWS OF THE CARBONATE CHIMNEYS AT THE POINT DUME METHANE SEEP OFF SOUTHERN CALIFORNIA ARE COVERED WITH COLORFUL MICROBIAL MATS AND PERMEATED BY METHANE-EATING MICROBES. view more
CREDIT: COURTESY OF COURTESY OF THE SCHMIDT OCEAN INSTITUTE (PERMISSION TO USE WITH PROPER CITATION)
Methane is a strong greenhouse gas that plays a key role in Earth's climate. Anytime we use natural gas, whether we light up our kitchen stove or barbeque, we are using methane.
Only three sources on Earth produce methane naturally: volcanoes, subsurface water-rock interactions, and microbes. Between these three sources, most is generated by microbes, which have deposited hundreds of gigatons of methane into the deep seafloor. At seafloor methane seeps, it percolates upwards toward the open ocean, and microbial communities consume the majority of this methane before it reaches the atmosphere. Over the years, researchers are finding more and more methane beneath the seafloor, yet very little ever leaves the oceans and gets into the atmosphere. Where is the rest going?
A team of researchers led by Jeffrey J. Marlow, former postdoctoral researcher in Organismic and Evolutionary Biology at Harvard University, discovered microbial communities that rapidly consume the methane, preventing its escape into Earth's atmosphere. The study published in Proceedings of the National Academy of Sciences collected and examined methane-eating microbes from seven geologically diverse seafloor seeps and found, most surprisingly, that the carbonate rocks from one site in particular hosts methane-oxidizing microbial communities with the highest rates of methane consumption measured to date.
"The microbes in these carbonate rocks are acting like a methane bio filter consuming it all before it leaves the ocean," said senior author Peter Girguis, Professor of Organismic and Evolutionary Biology, Harvard University. Researchers have studied microbes living in seafloor sediment for decades and know these microbes are consuming methane. This study, however, examined microbes that thrive in the carbonate rocks in great detail.
Seafloor carbonate rocks are common, but in select locations, they form unusual chimney-like structures. These chimneys reach 12 to 60 inches in height and are found in groups along the seafloor resembling a stand of trees. Unlike many other types of rocks, these carbonate rocks are porous, creating channels that are home to a very dense community of methane-consuming microbes. In some cases, these microbes are found in much higher densities within the rocks than in the sediment.
During a 2015 expedition funded by the Ocean Exploration Trust, Girguis discovered a carbonate chimney reef off the coast of southern California at the deep sea site Point Dume. Girguis returned in 2017 with funding from NASA to build a sea floor observatory. Upon joining Girguis's lab, Marlow, currently Assistant Professor of Biology at Boston University, was studying microbes in carbonates. The two decided to conduct a community study and gather samples from the site.
"We measured the rate at which the microbes from the carbonates eat methane compared to microbes in sediment," said Girguis. "We discovered the microbes living in the carbonates consume methane 50 times faster than microbes in the sediment. We often see that some sediment microbes from methane-rich mud volcanoes, for example, may be five to ten times faster at eating methane, but 50 times faster is a whole new thing. Moreover, these rates are among the highest, if not the highest, we've measured anywhere."
"These rates of methane oxidation, or consumption, are really extraordinary, and we set out to understand why," said Marlow.
The team found that the carbonate chimney sets up an ideal home for the microbes to eat a lot of methane really fast. "These chimneys exists because some methane in fluid flowing out from the subsurface is transformed by the microbes into bicarbonate, which can then precipitate out of the seawater as carbonate rock," said Marlow. "We're still trying to figure out where that fluid - and its methane - is coming from."
The micro-environments within the carbonates may contain more methane than the sediment due to its porous nature. Carbonates have channels that are constantly irrigating the microbes with fresh methane and other nutrients allowing them to consume methane faster. In sediment, the supply of methane is often limited because it diffuses through smaller, winding channels between mineral grains.
A startling find was that, in some cases, these microbes are surrounded by pyrite, which is electrically conductive. One possible explanation for the high rates of methane consumption is that the pyrite provides an electrical conduit that passes electrons back and forth, allowing the microbes to have higher metabolic rates and consume methane quickly.
"These very high rates are facilitated by these carbonates which provide a framework for the microbes to grow," said Girguis. "The system resembles a marketplace where carbonates allow a bunch of microbes to aggregate in one place and grow and exchange - in this case, exchange electrons - which allows for more methane consumption."
Marlow agreed, "When microbes work together they're either exchanging building blocks like carbon or nitrogen, or they're exchanging energy. And one kind of way to do that is through electrons, like an energy currency. The pyrite interspersed throughout these carbonate rocks could help that electron exchange happen more swiftly and broadly."
In the lab, the researchers put the collected carbonates into high pressure reactors and recreated conditions on the sea floor. They gave them isotopically labeled methane with added Carbon-14 or Deuterium (Hydrogen-2) in order to track methane production and consumption. The team next compared the data from Point Dume to six additional sites, from the Gulf of Mexico to the coast of New England. In all locations, carbonate rocks at methane seeps contained methane-eating microbes.
"Next we plan to disentangle how each of these different parts of the carbonates - the structure, electrical conductivity, fluid flow, and dense microbial community - make this possible. As of now, we don't know the exact contribution of each," said Girguis.
"First, we need to understand how these microbes sustain their metabolic rate, whether they're in a chimney or in the sediment. And we need to know this in our changing world in order to build our predictive power," said Marlow. "Once we clarify how these many interconnected factors come together to turn methane to rock, we can then ask how we might apply these anaerobic methane-eating microbes to other situations, like landfills with methane leaks."
