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)
Sunday, March 22, 2020
Scientists assess the accelerated changes of glaciers in the Yulong Snow Mountain
Natural-colour satellite image of the Tibetan Plateau. Credit: NASA
The Yulong Snow Mountain (YSM) is a region of temperate glaciers in the southeast Qinghai-Tibetan Plateau. As one of the most famous tourist attractions in Yunnan Province, the existence of the ice-and-snow landscapes of the YSM is culturally important to the Lijiang ancient town.
Recently, scientists from Northwest Institute of Eco-Environment and Resources, together with their colleagues from other universities in China, systematically assessed the glacier changes of the YSM during the past several decades using ground-based and remotely sensed observations and referencing topographic maps.
They assessed glacier changes in the YSM and their impact on the local glacier tourism. Based on in situ data and remote-sensing images, scientists first evaluated the glacier changes in the study region, such as changes in the glacier front, glacier area and glacier mass balance.
Besides, they analyzed the reasons for this glacier change, along with the climate records from a local meteorological station, followed by the major impact factors of the initially rapid glacier retreat.
The findings of the present study help to understand the mechanism between accelerated ablation of temperate glaciers and climate change in southeast regions of Qinghai-Tibetan Plateau and provide references for local tourism administrations.
This study has been published in Regional Environmental Change in an article titled "Accelerated changes of glaciers in the Yulong Snow Mountain, Southeast Qinghai-Tibetan Plateau."Observational evidence of Karakoram anomaly
More information: Shijin Wang et al. Accelerated changes of glaciers in the Yulong Snow Mountain, Southeast Qinghai-Tibetan Plateau, Regional Environmental Change (2020). DOI: 10.1007/s10113-020-01624-7
Canada's changing coronavirus border policy exposes international students' precarious status
Canada’s announcements about its border have not left international students with a sense of security. Credit: Shutterstock
Canada's border closure announcements have thrown international students and other foreign nationals on a roller coaster of anxiety that jeopardizes many people's sense of wellness and security.
But both in the short term, as officials at many levels respond to changing circumstances and messaging, and over the longer term, as our society adapts to the pandemic, it's far from clear that Canada's announcements will provide international students or temporary foreign workers with a sense of security.
Key concerns remain unaddressed. How effectively has, or will, Canada communicate its border decisions about international students and temporary foreign workers to border officials, airlines and the students themselves? Do these changing messages in a short time signal that international students should be concerned for the future of their mobility and their studies? How is the well-being of international students and other temporary residents in Canada impacted by wondering if the border could be closed to them?
Potential consequences
It is important to understand how temporary residents—those without permanent residency—such as international students, temporary foreign workers and other precarious status foreigners who have been legally living, studying and working in Canada for months or years —have been affected by these announcements.
Will international students, foreign workers or the Canadian public now be wondering whether temporary residents have become disposable foreigners amid COVID-19 pandemic? Indeed, as they were not addressed in Trudeau's initial announcement, they may be wondering whether their temporary resident status is worthy of Canadian state consideration and protection or it is an item that can be disposed of in times of crisis.
It is understandable that the federal government's aggressive measures aim to protect Canadians and permanents residents of Canada. It is also clear that "we are in a fairly critical period" to slow the spread of COVID-19, as Canada's Chief Public Health Officer Dr. Theresa Tam said.
However, talking about closing the border to those who have lived, studied and worked in Canada for months or years raises concerns about how we should help each other amid the COVID-19 pandemic while respecting human rights and dignity.
Respecting human rights
As the United Nations High Commissioner for Refugees recommended, states are of course entitled to take measures to ascertain and manage risks to public health, including risks that could arise in connection with non-nationals arriving at their borders. Such measures must be non-discriminatory as well as necessary, proportionate and reasonable with the aim of protecting public health.
What protection and relief measures can international students and temporary foreign workers expect from the federal government as conditions surrounding the pandemic change?
International students are clearly concerned about their precarious situations. Will Canada offer any official relief measures or supports for international students too, like rent relief?
Precarious status and well-being
The prime minister's announcement of Canada's border closure to all foreigners may have had a significant impact on the mental and physical health of international students who are temporary residents in Canada, and have been living and working in the country.
Students' health and wellness may have been affected by knowing that if they leave the country, they will not be able to come back to continue their studies, research or work. This may also impact the Canadian economy.
Even though it was corrected two days later, Canada's decisions and messaging prompt us to reflect on how we should apply measures of social distancing that are not harmful to others and that still protect human dignity—and to consider how we should account for and help each other in times of crisis. We're also prompted to think about how we should address popular concerns while remaining caring, thoughtful and welcoming to others.Canada-US border likely to be closed by Saturday: Trudeau
Since the outbreak, the Indonesian government has made public calls for people to self-isolate if they have symptoms. Self-isolation means staying indoors and completely avoiding contact with other people.
Public health experts have encouraged the public to self-isolate for at least 14 days to contain the rapid spread of the coronavirus. Research has shown that self-isolation is highly effective, especially when the majority of COVID-19 cases do not show symptoms.
Even though this preventive action is proven effective, it fails to take into account the fact that many poor and low-income people cannot afford to self-isolate.
People working in informal sectors and casuals like online drivers, grocery store assistants and kitchen hands do not have the luxury of working from home as their jobs cannot be done remotely.
In 2019, people working in informal sectors accounted for 57.2% of Indonesia's workforce, or around 74 million people. As many as 25.14 million people live under the poverty line—that's about 9% of Indonesia's population.
Two weeks of self-isolation means these people risk losing their sole income source.
The poor narratives
The COVID-19 pandemic has hurt the economy worldwide. Many companies have reported losses as demand drops. With business slowing down, workers are facing greater risks of losing their jobs and income. It is happening in Indonesia.
"Ohh so sad. No turis [tourists] no job," posted one online driver on his social media just three days after the government declared COVID-19 a national disaster.
Online drivers are also prone to coronavirus infections as they meet many different people in the course of their work.
GOJEK, one of the largest online driver platforms in Indonesia, has suspended the account of one of its drivers who was suspected of having COVID-19. But how will the driver get his income?
A similar story involves a 36-year-old casual domestic worker and mother from Yogyakarta, about 500 kilometers from the capital Jakarta.
"I can't afford to self-isolate. I need to go to work," she said. "No work means no money, and no money means no food for my kids."
These accounts illustrate the difficult situations facing many blue-collar workers during the COVID-19 pandemic. They can not afford to take a day off, let alone two weeks.
What can be done
To minimize discriminatory policies against poor people during the COVID-19 pandemic, the government should address the underlying and structural issues that create vulnerabilities in the first place.
This can be done, for example, by strengthening poverty eradication programs and establishing universal health coverage for low-income households.
The government must allocate a budget to provide primary health services to poor people. These services include providing access to health education,safe drinking water, nutrition, immunization and treatment of communicable and non-communicable diseases.
In addition, the government should address more fundamental problems related to the changing nature of work during the pandemic.
One of the strategies required is to provide social assistance and social insurance for people working in informal sectors during the COVID-19 emergency period.
Without adequate support from the government, many of these people face a higher risk of losing their income or contracting the disease and then spreading the virus.
Therefore, any public health measures to mitigate multiple impacts of the COVID-19 pandemic must seriously consider the society's various economic and social backgrounds to ensure preventive measures do not further punish already marginalized and vulnerable communities.
By strengthening the nation's social welfare and health care systems, the government can help keep all citizens both physically and economically healthy and also protect the vulnerable during the pandemicCoronavirus: 10 questions about self-isolation answered
In the wake of bushfires and coronavirus, it's time we talked about human security
The term "human security" was first adopted by the United Nations Development Program in 1994. We speak far less of it now than we did then. Yet the cataclysmic events of this year should remind us national security is no longer to be thought of in terms of conventional warfare and military expenditure.
Put simply, human security encompasses all those threats to survival that are not military or state-sponsored, and therefore tend to fall beneath the radar of those who imagine security in conventionally "hard" terms.
The recent bushfires and the coronavirus pandemic reveal imminent threats from climate change and global diseases that threaten the very survival of what we take for granted. Yet governments have been far less willing to commit to responding to these issues than to increasing military budgets.
When the concept of human security emerged it was designed to address seven themes: "economic, food, health, environmental, personal, community and political security". While these terms may seem too broad to be useful, all of them are directly related to the crises now facing the world.
These crises have taken me back to a large research project with several colleagues on rethinking the relevance of human security.
There is a voluminous literature on the meaning and limitations of human security. When he launched the book based on our research, the former foreign minister Gareth Evans defined it as an attempt to link conventional understandings of national security with the needs of human development: "The concept of human security was broad enough to advance both freedom from fear and freedom from want."
In the book, I wrote: "Australia is unlikely to face a military invasion, of the sort we might have experienced in World War II, but its security is threatened by a series of global upheavals around food, water, new epidemics, transnational crime and climate change."
I might now add cybersecurity to that list.
Over the past few years, the Australian government has increased military expenditures to the point where we are now among the top 15 countries ranked on defence spending.
Of course, our expenditure is trivial compared to the United States and China, but there is a powerful lobby pushing to increase it. At the same time, the government has made major cuts to overseas development assistance, is resisting the need to seriously cut emissions and appeared unprepared for the severity of the coronavirus epidemic.
Growing concern about the rise of China and the unpredictability of the United States has meant we ignore the more immediate threats to our security, even as they are looming around us. Most troubling, perhaps, is the government's dislike of global institutions in a period when we need global cooperation more than ever.
Prime Minister Scott Morrison has made several attacks on what he terms an "unaccountable internationalist bureaucracy". In this he appears to be following the lead of US President Donald Trump. Our declining foreign assistance budget is lessening the capacity of countries in our region to respond to health and climate emergencies.
The failure of the United States to provide leadership on either climate change or the coronavirus has emphasised the importance of great powers grasping that even their survival depends upon global action. Arguably the authoritarian Chinese regime, for all its unpleasantness, understands this better than the Trump administration.
It is a common aphorism that generals always fight the last war. Debates about the rise of China and the need to increase our military capabilities overlook the fact the most immediate threats to national security are not conventional military ones.
There are hints of this in Australia's foreign policy. A statement from Foreign Minister Marise Payne noted: "Australia's longstanding and ongoing security cooperation with Pacific countries covers defence, law enforcement, transnational crime, climate and disaster resilience, border management and human security."
But the shadow minister, Penny Wong, has argued: "'Security' has a much broader connotation than the more threat-based protective and response concepts on which a lot of public policy concentrates."
But these statements stand apart from mainstream debates about "national security", which remain dominated by concerns about military build-ups and terrorism.
After unparalleled bushfires and coronavirus, the concept of human security gives us the language to reassess the most immediate threats to our survival and the need for global cooperation to respond to them.
Pushing manufacturers to make more resilient products will curb e-waste
European lawmakers are considering new regulations that would push manufacturers to design products that last longer. It's part of a global effort to curb "throwaway" culture where people buy products, use them for a short while and then throw them away.
Cliff Davidson, professor of engineering and environmental engineering program director at Syracuse University, commends the move. Instead of a culture centered around buying new things, Prof. Davidson advocates for a culture where rentals are more common. He says Americans may rebel against the practice, but serious change is needed to disrupt the status quo.
Davidson says:
"This problem with electronic waste is that it's just the tip of the iceberg of all of our wastes… the real problem is about much more than e-waste. One of the key problems is that in order to keep many companies in profit mode, they need to have a continual demand for their product. What that means is they don't want to build a cell phone that lasts forever because there won't be people buying as many new cell phones as there are now. A lot of what we use, even outside of electronics, is built to eventually have problems with the physical device or to become less useful due to obsolescence (such as computers). If you have a laptop for more than a few years, it will probably be out of date because newer versions have more capabilities… it makes consumers want new ones. Manufacturers want to have continuous demand.
"There is one proposal that has been floated by others that I tend to agree with. It centers around the idea is that we shouldn't be purchasing devices, but rather we should be renting them. That goes for everything from cell phones and computers to dishwashers and dryers and washers, air conditioners, etc. If we practiced renting instead of buying, there would be a tremendous incentive for manufacturers to build products that last. The manufacturer would be responsible for repairs and they would build their products so that those repairs were minimal.
"I suspect that in some cultures, people would be willing to go rent rather than buy. But I expect Americans would rebel against that. It's a change in thinking about how you consume items and how you shop.
"Rebellion or not, we can't keep the status quo. We have to make changes and I do think putting more pressure on manufacturers to make more sustainable products is a step in the right direction."
How do you measure the economic impact of coronavirus?
A UChicago economist says to look at power demands. Credit: Shutterstock.com
With Americans largely self-isolating amid concerns about COVID-19, some of the hardest hit areas are already seeing electricity demand begin to weaken. Could this be a sign of things to come?
University of Chicago economist Steve Cicala examined what has happened to power demand in Northern Italy, which some say is about 11 days ahead of the U.S. trajectory of the novel coronavirus. An assistant professor at the Harris School of Public Policy, Cicala compiled regional grid data, adjusting for weather changes, and found that power demand has plunged in Northern Italy since the middle of February.
On Friday, Feb. 21, life in the region was largely normal. The following day, the Italian government began to institute quarantine measures. By Monday, power demand began to slow. As the chart below shows, there was then a bump in power just before the government instituted a national lockdown about two weeks later on March 10. About a week after that, power demand had fallen 18% compared to demand just prior to the quarantine measures.
An expert on the economics of environmental and energy policy regulation, Cicala said power demand could be a real-time indicator of the more widespread impacts on the Italian economy. And, what is happening in Italy could point to what the United States could expect in the coming weeks as states issue tighter restrictions on daily life.
Credit: Energy Policy Institute at the University of Chicago
"If paychecks and employment follow what is happening in the electricity-demand data, then there are a lot of people who will need help," said Cicala, a research affiliate for the Energy Policy Institute at the University of Chicago.
When there is a sharp shock in the economy, he explained, other indicators like employment may lag in reflecting the impact. This is because companies often lay off workers as a last resort, after they have already taken other measures like ramping down production or adjusting maintenance schedules. Conversely, electricity demand shows the more immediate change and is a broad measure of economic activity.
This pattern was on display during the last recession in the United States. U.S. power demand began to fall a month before the official start date of the recession in December 2007, according to the National Bureau of Economic Research—a date that was determined after an additional year of data had been collected.
As policymakers today consider which countermeasures may be necessary to buffer the economic effects of coronavirus, a real-time indicator of the economy's strength is of the utmost importance.
Banner Image: The Sun is Earth's primary power source. Energy from the Sun, called solar irradiance, drives Earth's climate, temperature, weather, atmospheric chemistry, ocean cycles, energy balance and more. Credit: NASA / Scott Wiessinger
After nearly two decades, the Sun has set for NASA's SOlar Radiation and Climate Experiment (SORCE), a mission that continued and advanced the agency's 40-year record of measuring solar irradiance and studying its influence on Earth's climate.
The SORCE team turned off the spacecraft on February 25, 2020, concluding 17 years of measuring the amount, spectrum and fluctuations of solar energy entering Earth's atmosphere—vital information for understanding climate and the planet's energy balance. The mission's legacy is continued by the Total and Spectral solar Irradiance Sensor (TSIS-1), launched to the International Space Station in December 2017, and TSIS-2, which will launch aboard its own spacecraft in 2023. Monitoring Earth's "Battery"
The Sun is Earth's primary power source. Energy from the Sun, called solar irradiance, drives Earth's climate, temperature, weather, atmospheric chemistry, ocean cycles, energy balance and more. Scientists need accurate measurements of solar power to model these processes, and the technological advances in SORCE's instruments allowed more accurate solar irradiance measurements than previous missions.
"These measurements are important for two reasons," said Dong Wu, project scientist for SORCE and TSIS-1 at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Climate scientists need to know how much the Sun varies, so they know how much change in the Earth's climate is due to solar variation. Secondly, we've debated for years, is the Sun getting brighter or dimmer over hundreds of years? We live only a short period, but an accurate trend will become very important. If you know how the Sun is varying and can extend that knowledge into the future, you can then put the anticipated future solar input into climate models together with other information, like trace gas concentrations, to estimate what our future climate will be."
SORCE's four instruments measured solar irradiance in two complementary ways: Total and spectral.
Total solar irradiance, or TSI, is the total amount of solar energy that reaches the Earth's outer atmosphere in a given time. Sunspots (darkened areas on the Sun's surface) and faculae (brightened areas) create tiny TSI variations that show up as measurable changes in Earth's climate and systems. From space, SORCE and other solar irradiance missions measure TSI without interference from Earth's atmosphere.
SORCE's TSI values were slightly but significantly lower than those measured by previous missions. This was not an error—its Total Irradiance Monitor was ten times more accurate than previous instruments. This improved solar irradiance inputs into the Earth climate and weather models from what was previously available.
"The big surprise with TSI was that the amount of irradiance it measured was 4.6 watts per square meter less than what was expected," said Tom Woods, SORCE's principal investigator and senior research associate at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado. "That started a whole scientific discussion and the development of a new calibration laboratory for TSI instruments. It turned out that the TIM was correct, and all the past irradiance measurements were erroneously high."
"It's not often in climate studies that you make a quantum leap in measurement capability, but the tenfold improvement in accuracy by the SORCE / TIM was exactly that," said Greg Kopp, TIM instrument scientist for SORCE and TSIS at LASP.
SORCE's other measurements focused on spectrally-resolved solar irradiance (SSI): The variation of solar irradiance with wavelength across the solar spectrum, covering the major wavelength regions important to Earth's climate and atmospheric composition.
Besides the familiar rainbow of colors in visible light, solar energy also contains shorter ultraviolet and longer infrared wavelengths, both of which play important roles in affecting Earth's atmosphere. Earth's atmospheric layers and surface absorb different wavelengths of energy—for example, atmospheric ozone absorbs harmful ultraviolet radiation, while atmospheric water vapor and carbon dioxide absorb longer-wavelength infrared radiation, which keeps the surface warm. SORCE was the first satellite mission to record a broad spectrum of SSI for a long period, tracking wavelengths from 1 to 2400 nanometers across its three SSI instruments.
NASA's Solar Radiation and Climate Experiment, or SORCE, collected this data on total solar irradiance, the total amount of the Sun’s radiant energy, throughout Sept. 2017. Sunspots (darkened areas on the Sun’s surface) and faculae (brightened areas) create tiny TSI variations that show up as measurable changes in Earth’s climate and systems. Credit: NASA / Walt Feimer
"For public health, ozone chemistry and ultraviolet radiation are very important, and visible light is important for climate modeling," Wu said. "We need to know the solar variability at different wavelengths and compare these measurements with our models."
SORCE observed the Sun across two solar minima (periods of low sunspot activity), providing valuable information about variability over a relatively short 11-year period. But a longer record is needed to improve long-term predictions, Wu said. Buying Time for an Aging Mission
SORCE was originally designed to collect data for just five years. Extending its lifespan to 17 required creative and resourceful engineering, said Eric Moyer, SORCE's mission director at Goddard.
SORCE's battery began to degrade in its eighth year of operations, no longer providing enough power to support consistent data collection. Unfortunately, the NASA instrument designed to take up its TSI measurements, Glory, was lost shortly after its 2011 launch, and the next instrument, the NOAA / U.S. Air Force Total solar irradiance Calibration Transfer Experiment (TCTE), would not launch until 2013. If SORCE could no longer operate, the ongoing solar irradiance record could be interrupted. Because the Sun changes very slowly—its sunspots and faculae follow an 11-year cycle, and some changes span decades or even centuries—a long, continuous record is essential for understanding how the Sun behaves.
The engineering team switched to daytime-only solar data collection, powering down the instruments and part of the spacecraft during the night part of the SORCE orbit. This plan effectively allowed the satellite to run with no functioning battery, Woods said—a groundbreaking engineering achievement.
"The operation and science teams at our partner organizations developed and implemented a completely new way to operate this mission when it appeared it was over because of battery capacity loss," said Moyer. LASP and Northrup Grumman Space Systems led the development of new operational software in order to continue the SORCE mission. "The small, highly dedicated team persevered and excelled when encountering operational challenges. I am very proud of their excellent accomplishment and honored to have had the opportunity to participate in managing the SORCE mission." Continuing a Bright Legacy
As SORCE's time in the Sun ends, NASA's solar irradiance record continues with TSIS-1. The mission's two instruments measure TSI and SSI with even more advanced instruments that build on SORCE's legacy, said Wu. They have already enabled advances like establishing a new reference for the "quiet" Sun when there were no sunspots in 2019, and for comparing this to SORCE observations of the previous solar cycle minimum in 2008.
TSIS-2 is scheduled to launch in 2023 with identical instruments to TSIS-1. Its vantage point aboard its own spacecraft will give it more flexibility than TSIS-1's data collection aboard the ISS.
"We are looking forward to continuing the groundbreaking science ushered in by SORCE, and to maintaining the solar irradiance data record through this decade and beyond with TSIS-1 and 2," said LASP's Peter Pilewskie, principal investigator for the TSIS missions. "SORCE set the standard for measurement accuracy and spectral coverage, two attributes of the mission that were key to gaining insight into the Sun's role in the climate system. TSIS has made additional improvements that should further enhance Sun-climate studies."
"Solar irradiance measurements are very challenging, and the SORCE team proposed a different way, a new technology, to measure them," said Wu. "Using advanced technology to advance our science capability, SORCE is a very good example of NASA's spirit."SORCE satellite: A Decade in the Sun
Middle-aged entrepreneurs fare better than twentysomethings
Two years ago, MIT economist Pierre Azoulay started a lively discussion when a working paper he co-authored, "Age and High-Growth Entrepreneurship," revealed a surprising fact about startup founders: Among firms in the top 1/10 of the top 1 percent, in terms of growth, the average founder's age is 45. That's contrary to the popular image of valuable startups being the sole domain of twentysomething founders, such as Mark Zuckerberg of Facebook.
The paper, written with Benjamin Jones of Northwestern University, J. Daniel Kim of the University of Pennsylvania, and Javier Miranda of the U.S. Bureau of the Census, has now been officially published, in the journal American Economics Review: Insights. MIT News spoke to Azoulay, the International Programs Professor of Management at the MIT Sloan School of Management, about the finding and the discussion it has generated.
Q: What has been the response of people to the study?
A: We're documenting a fact, and that fact either accords with people's intuitions, or it doesn't. Some people are genuinely surprised because they've lived in the current zeitgeist, and then once they start thinking about it, they say, "Ah, it makes sense." And then there are people who say, "Oh, I knew it all along!" But Silicon Valley venture capitalists have studiously avoided engaging with what we've done. And I don't know why.
I think one line of [venture capitalist] skepticism is to say, "Well, you may well be right, but you're studying the one-in-a-thousand firm, and we're [investing in] the one-in-a-million firm." Which is sort of like restating that Apple, Microsoft, and Google were founded by young people.
Yes, we already knew it is possible for very large, successful firms to be founded by very young people. The question is: Is it likely?
Q: As you continue to think about this subject, is it possible to say what accounts for the success of relatively older entrepreneurs? Experience, intellectual capital, greater business connections—what matters?
A: All of those things are not mutually exclusive, and they're all likely to play a role. They just need to be studied separately, if you will. We have to remain agnostic. But there is one key point in my view. Forget experience: How about just knowledge? I like to say there is no such thing as a 25-year-old biotech entrepreneur. That person just doesn't exist, because you need a Ph.D. and three postdocs [to gain high-level knowledge]. There are lots of fields where if you want to make a contribution, you have to bring yourself to the frontier of knowledge in a domain, and that takes time. And that's not going to be the realm of the 22-year-old.
Beyond the big platform IT companies, if you're thinking about the broader swath of entrepreneurship across a multiplicity of sectors, then you have to acknowledge this point. In some sense, if you recognize the diversity of startups, the [founder's] age number is going to be higher than if you're only focused on super-high-value Silicon Valley internet companies. So we need a basic attitude adjustment.
Q. Even as people mythologize the young startup founder, there is also a tech-sector ethos that heralds serial entrepreneurship and tolerates failure, because you're taking risks and learning by doing. Isn't that one Silicon Valley notion that might correspond to what you discovered?
A: Yes, one thing that could explain our results is entrepreneurship being an activity you can learn to do better over time. That's certainly something we've heard. We can't pin it down, but if I had to think of the most likely stories, that's certainly one. Even within a particular sector that demands a certain amount of intellectual capital, holding that constant, even within biotech or clean energy, you might think there is something about learning by founding, which is going to lead to a correlation between success and a higher age for founders.The 20-year-old entrepreneur is a myth, according to study
Scorched landscapes and animal corpses brought into sharp relief what climate-driven changes to wildfire mean for Australia's plants and animals.
Yet the effects of fire go much deeper, quite literally, to a vast and complex underground world that we know stunningly little about, including organisms that might be just as vulnerable to fire, and vital to Australia's ecological recovery: the fungi.
Plants and fungi: a match made underground
The aftermath of wildfires can make landscapes appear devoid of life. Yet under the ash beds lies a vast living network of fungi.
One group of fungi, called arbuscular mycorrhizal (AM) fungi, form symbiotic relationships with most of the world's land plants. This means most plants and AM fungi rely on each other to grow and thrive.
Extensive networks of AM fungal mycelium (a vegetative part of a fungus, akin to plant roots) explore the soil to access nutrients beyond the reach of their plant partners. The mycelium forms a fungal underground highway, transporting the valuable nutrients back to the plants.
Fungi play a crucial role in ecosystems around the world.
Amanita sp, Geastrum sp and Aseroe sp. Credit: Adam Frew
In return for the nutrients they provide, AM fungi receive sugar made by plants through photosynthesis. For many species, this means without a plant host the fungi won't last.
The responses of plants and AM fungi to fire are therefore deeply intertwined: the recovery of one is dependent on the other. Yet ecologists are only beginning to learn how fire affects fungi and what role they might have in hastening ecosystem recovery following wildfires.
Fungi and fire: what do we know?
Studies have shown fungi living near the soil surface are particularly susceptible to fire, often killed by high soil temperatures as the fire passes over. Fungi further below the surface are relatively more protected, and may provide the nuclei for recovery.
Fungi provide access to nutrients such as phosphorus, and plants provide carbon as sugar and fats. Credit: Adam Frew via BioRender
But, as with animals, surviving fire is only half the battle. When fire removes vegetation, it suddenly halts sugar and fats plants produce, delivered to the fungi below-ground.
Another challenge is the ways fire influences the underground world, such as changes in soil acidity, soil carbon, nutrient dynamics, and soil water. For instance, soils with more acidity tend to have less diversity of AM fungi.
The combination of high temperatures and changed conditions appear to take a toll on fungi: a 2017 meta-analysis of 29 studies found fire reduces the number of fungal species by about 28%. And given the severity of last summer's bushfires, we can expect that many fungal communities below the surface have been lost, too.
Arbuscular mycorrhizal fungi colonising a plant root. Credit: Adam Frew
Changes in the number and types of AM fungal species can strongly determine how well plants recover, and can influence the whole ecosystem after fire. For example, plants could be left more vulnerable to disease if fungi supporting native plantchemical or physical defences are reduced by fire.
Since we know fungi are particularly important to plants in times of ecological stress, their role may be paramount in harsh post-fire landscapes. But while firefighters and wildlife carers have gone to inspiring lengths to protect plants and animals, we know little about how to help AM fungi recovery from the bushfires, or if help is even necessary.
Helping fungi help ecosystems
Research from last year showed reintroducing AM fungal communities (usually as an inoculant or biofertiliser) to degraded and disturbed landscapes can increase plant diversity by around 70%, encourage recovery of native plants, and suppress invasive weeds.
Fire tends to change what species of arbuscular mycorrhizal fungi are present in the soil as ecosystems recovery. Credit: Adam Frew via BioRender
How exactly fungi and fire interact remains an ecological mystery.
Credit: Coprinus sp. Adam Frew
Amanita muscaria (Fly agaric). Credit: Adam Frew
Fire tends to change what species of arbuscular mycorrhizal fungi are present in the soil as ecosystems recovery. Credit: Adam Frew via BioRender
How exactly fungi and fire interact remains an ecological mystery. Credit: Coprinus sp. Adam Frew
Taking a similar approach and actively putting fungi back into fire-affected environments could ensure more rapid or more complete recovery of native vegetation, including the survival of endangered plant species threatened by the fires.
However, it's important to consider which AM fungi are reintroduced. They should be species normally present in the local area, and suited to support recovering plant communities.
An underlying virus does not stop the body's immune system from launching a strong defense against a second, newly introduced virus, according to a Yale-led study that appears in the March 9 online edition of the journal PLOS Neglected Tropical Diseases.
For the study, Yale researchers obtained blood samples from patients from India with dengue infection, working in partnership with investigators from The National Institute of Mental Health and NeuroSciences in India and their colleagues at Apollo Hospital in Bangalore. They then infected these samples with the Zika virus and measured the cells' immune response using advanced cell-profiling technology. The researchers found that the underlying dengue infection did not stop the cells from launching a robust immune response against the newly introduced Zika virus.
"The message from our paper is that your innate immune system is ready to launch a very powerful response to a new pathogen," said Ruth Montgomery, professor of medicine and epidemiology and associate dean for scientific affairs, and the paper's lead author.
Montgomery and her team tested samples from both dengue patients and healthy controls from India and found that the underlying dengue infection did not impair new immune responses to the Zika virus. Specifically, researchers noted an increase in small proteins called cytokines, which are related to fighting off infection, in 36 individual cell subsets when Zika was introduced.
"Patients with acute dengue still had a strong immune response to the Zika virus," said Montgomery. "Their immune response was not diminished."
Both the dengue virus and Zika virus are mosquito-borne human pathogens that have caused significant public health concern across the globe. There are some 50-100 million estimated dengue infections, leading to fever, headaches, joint pain, and more severe shock syndrome; the Zika virus has been shown to be devastating to babies in utero, and has led to over 6,700 cases of deformities and neurological damage in newborns. Because the vectors for disease transmission are the same, certain regions are highly prone to both, including Brazil, which had a Zika epidemic in 2015. When the dengue samples were collected from India for the study, Zika was not yet a public health threat in that country. By 2018, that had changed, with 94 confirmed Zika cases, and widespread monitoring.
These findings provide a much more in-depth look at the body's response to viruses at the single-cell level, which Montgomery noted are consistent with existing literature. The research was part of a the HIPC consortium funded by the National Institutes of Health to better understand human immunology, infectious disease, and vaccination responses.
To measure immune response, she and her team used mass cytometry or CyTOF (Cytometry by Time-of-Flight), a state-of-the-art method for simultaneously revealing multiple components of the responses of distinct immune cell populations. Analysis of the results was done using SAUCIE, a novel deep-learning algorithm developed by a team in the lab of Smita Krishnaswamy, assistant professor of genetics and computer science at Yale. Montgomery, director of the Yale CyTOF facility, said Yale is at the forefront of advanced cell analysis, and one of the first academic medical centers with a CyTOF Imaging Mass Cytometer, which further extends its capabilities.
The findings can help guide scientists' understanding of all emerging infectious diseases, including coronavirus, something Montgomery's lab is now actively investigating.
"We are set up to investigate human immune cell response to viruses and have several collaborations currently underway to collect samples related to the coronavirus," Montgomery said. "We have containment facilities and excellent virologists at Yale, and there is a lot of activity right now," she added.
More information: Yujiao Zhao et al. Single cell immune profiling of dengue virus patients reveals intact immune responses to Zika virus with enrichment of innate immune signatures, PLOS Neglected Tropical Diseases (2020). DOI: 10.1371/journal.pntd.0008112