How caloric restriction prevents negative effects of aging in cells

Peas on plate, dieting concept (stock image).

If you want to reduce levels of inflammation throughout your body, delay the onset of age-related diseases, and live longer, eat less food. That's the conclusion of a new study by scientists from the US and China that provides the most detailed report to date of the cellular effects of a calorie-restricted diet in rats. While the benefits of caloric restriction have long been known, the new results show how this restriction can protect against aging in cellular pathways, as detailed in Cell on February 27, 2020.

"We already knew that calorie restriction increases life span, but now we've shown all the changes that occur at a single-cell level to cause that," says Juan Carlos Izpisua Belmonte, a senior author of the new paper, professor in Salk's Gene Expression Laboratory and holder of the Roger Guillemin Chair. "This gives us targets that we may eventually be able to act on with drugs to treat aging in humans."

Aging is the highest risk factor for many human diseases, including cancer, dementia, diabetes and metabolic syndrome. Caloric restriction has been shown in animal models to be one of the most effective interventions against these age-related diseases. And although researchers know that individual cells undergo many changes as an organism ages, they have not known how caloric restriction might influence these changes.

In the new paper, Belmonte and his collaborators -- including three alumni of his Salk lab who are now professors running their own research programs in China -- compared rats who ate 30 percent fewer calories with rats on normal diets. The animals' diets were controlled from age 18 months through 27 months. (In humans, this would be roughly equivalent to someone following a calorie-restricted diet from age 50 through 70.)

At both the start and the conclusion of the diet, Belmonte's team isolated and analyzed a total of 168,703 cells from 40 cell types in the 56 rats. The cells came from fat tissues, liver, kidney, aorta, skin, bone marrow, brain and muscle. In each isolated cell, the researchers used single-cell genetic-sequencing technology to measure the activity levels of genes. They also looked at the overall composition of cell types within any given tissue. Then, they compared old and young mice on each diet.

Many of the changes that occurred as rats on the normal diet grew older didn't occur in rats on a restricted diet; even in old age, many of the tissues and cells of animals on the diet closely resembled those of young rats. Overall, 57 percent of the age-related changes in cell composition seen in the tissues of rats on a normal diet were not present in the rats on the calorie restricted diet.

"This approach not only told us the effect of calorie restriction on these cell types, but also provided the most complete and detailed study of what happens at a single-cell level during aging," says co-corresponding author Guang-Hui Liu, a professor at the Chinese Academy of Sciences.

Some of the cells and genes most affected by the diet related to immunity, inflammation and lipid metabolism. The number of immune cells in nearly every tissue studied dramatically increased as control rats aged but was not affected by age in rats with restricted calories. In brown adipose tissue -- one type of fat tissue -- a calorie-restricted diet reverted the expression levels of many anti-inflammatory genes to those seen in young animals.

"The primary discovery in the current study is that the increase in the inflammatory response during aging could be systematically repressed by caloric restriction" says co-corresponding author Jing Qu, also a professor at the Chinese Academy of Sciences.

When the researchers homed in on transcription factors -- essentially master switches that can broadly alter the activity of many other genes -- that were altered by caloric restriction, one stood out. Levels of the transcription factor Ybx1 were altered by the diet in 23 different cell types. The scientists believe Ybx1 may be an age-related transcription factor and are planning more research into its effects.

"People say that 'you are what you eat,' and we're finding that to be true in lots of ways," says Concepcion Rodriguez Esteban, another of the paper's authors and a staff researcher at Salk. "The state of your cells as you age clearly depends on your interactions with your environment, which includes what and how much you eat."

The team is now trying to utilize this information in an effort to discover aging drug targets and implement strategies towards increasing life and health span.

Other researchers on the study were Shuai Ma, Shuhui Sun, Lingling Geng, Moshi Song, Wei Wang, Yanxia Ye, Qianzhao Ji, Zhiran Zou, Si Wang and Qi Zhou of the Chinese Academy of Sciences; Xiaojuan He, Wei Li, Piu Chan and Weiqi Zhang of Xuanwu Hospital Capital Medical University; Xiao Long of Peking Union Medical College Hospital; and Guoji Guo of Zhejiang University School of Medicine.

The work and researchers involved were supported by grants from the National Key Research and Development Program of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, Beijing Natural Science Foundation, Beijing Municipal Commission of Health and Family Planning, Advanced Innovation Center for Human Brain Protection, the State Key Laboratory of Membrane Biology, the Moxie Foundation, and the Glenn Foundation.

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Materials provided by Salk Institute. Note: Content may be edited for style and length.

How the solar system got its 'Great Divide,' and why it matters for life on Earth

Illustration of inner solar system (stock image).

Scientists, including those from the University of Colorado Boulder, have finally scaled the solar system's equivalent of the Rocky Mountain range.

In a study published today in Nature Astronomy, researchers from the United States and Japan unveil the possible origins of our cosmic neighborhood's "Great Divide." This well-known schism may have separated the solar system just after the sun first formed.

The phenomenon is a bit like how the Rocky Mountains divide North America into east and west. On the one side are "terrestrial" planet, such as Earth and Mars. They are made up of fundamentally different types of materials than the more distant "jovians," such as Jupiter and Saturn.

"The question is: How do you create this compositional dichotomy?" said lead author Ramon Brasser, a researcher at the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology in Japan. "How do you ensure that material from the inner and outer solar system didn't mix from very early on in its history?"

Brasser and coauthor Stephen Mojzsis, a professor in CU Boulder's Department of Geological Sciences, think they have the answer, and it may just shed new light on how life originated on Earth.

A sun disk holds vital clues

The duo suggests that the early solar system was partitioned into at least two regions by a ring-like structure that formed a disk around the young sun. This disk might have held major implications for the evolution of planets and asteroids, and even the history of life on Earth.

"The most likely explanation for that compositional difference is that it emerged from an intrinsic structure of this disk of gas and dust," Mojzsis said.

Mojzsis noted that the Great Divide, a term that he and Brasser coined, does not look like much today. It is a relatively empty stretch of space that sits near Jupiter, just beyond what astronomers call the asteroid belt.

But you can still detect its presence throughout the solar system. Move sunward from that line, and most planets and asteroids tend to carry relatively low abundances of organic molecules. Go the other direction toward Jupiter and beyond, however, and a different picture emerges: Almost everything in this distant part of the solar system is made up of materials that are rich in carbon.

This dichotomy "was really a surprise when it was first found," Mojzsis said.

Many scientists assumed that Jupiter was the agent responsible for that surprise. The thinking went that the planet is so massive that it may have acted as a gravitational barrier, preventing pebbles and dust from the outer solar system from spiraling toward the sun.

But Mojzsis and Brasser were not convinced. The scientists used a series of computer simulations to explore Jupiter's role in the evolving solar system. They found that while Jupiter is big, it was probably never big enough early in its formation to entirely block the flow of rocky material from moving sunward.

"We banged our head against the wall," Brasser said. "If Jupiter wasn't the agent responsible for creating and maintaining that compositional dichotomy, what else could be?"

A solution in plain sight

For years, scientists operating an observatory in Chile called the Atacama Large Millimeter/submillimeter Array (ALMA) had noticed something unusual around distant stars: Young stellar systems were often surrounded by disks of gas and dust that, in infrared light, looked a bit like a tiger's eye.

If a similar ring existed in our own solar system billions of years ago, Brasser and Mojzsis reasoned, it could theoretically be responsible for the Great Divide.

That's because such a ring would create alternating bands of high- and low-pressure gas and dust. Those bands, in turn, might pull the solar system's earliest building blocks into several distinct sinks -- one that would have given rise to Jupiter and Saturn, and another Earth and Mars.

In the mountains, "the Great Divide causes water to drain one way or another," Mojzsis said. "It's similar to how this pressure bump would have divided material" in the solar system.

But, he added, there's a caveat: That barrier in space likely was not perfect. Some outer solar system material may still have climbed across the divide. And those fugitives could have been important for the evolution of our own world.

"Those materials that might go to the Earth would be those volatile, carbon-rich materials," Mojzsis said. "And that gives you water. It gives you organics."

The rest is Earth history.

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Story Source:

Materials provided by University of Colorado at Boulder. Original written by Daniel Strain. Note: Content may be edited for style and length.

How to Unlock Your Hidden Creative Genius

This page pulls together my most essential information about creativity. I’ll share how creativity works, how to find your hidden creative genius, and how to create meaningful work by learning how to make creative thinking a habit. I’ve tried to present the basics of everything you need to know to start mastering creativity, even if you don’t have much time.

At the end of this page, you’ll find a complete list of all the articles I have written on creativity.

What is Creativity?

Let's define creativity.

The creative process is the act of making new connections between old ideas or recognizing relationships between concepts. Creative thinking is not about generating something new from a blank slate, but rather about taking what is already present and combining those bits and pieces in a way that has not been done previously.

While being creative isn't easy, nearly all great ideas follow a similar creative process. In 1940, an advertising executive named James Webb Young published a short guide titled, A Technique for Producing Ideas.

Young believed the process of creative connection always occurred in five steps.

The Creative Process

1. Gather new material. At first, you learn. During this stage you focus on 1) learning specific material directly related to your task and 2) learning general material by becoming fascinated with a wide range of concepts.
2. Thoroughly work over the materials in your mind. During this stage, you examine what you have learned by looking at the facts from different angles and experimenting with fitting various ideas together.
3. Step away from the problem. Next, you put the problem completely out of your mind and go do something else that excites you and energizes you.
4. Let your idea return to you. At some point, but only after you have stopped thinking about it, your idea will come back to you with a flash of insight and renewed energy.
5. Shape and develop your idea based on feedback. For any idea to succeed, you must release it out into the world, submit it to criticism, and adapt it as needed.

Is There Such a Thing as ‘Naturally Creative'?

While we often think of creativity as an event or as a natural skill that some people have and some don't, research  actually suggests that both creativity and non-creativity are learned.

According to psychology professor Barbara Kerr, “approximately 22 percent of the variance [in creativity] is due to the influence of genes.” This discovery was made by studying the differences in creative thinking between sets of twins. 

All of this to say, claiming that “I'm just not the creative type” is a pretty weak excuse for avoiding creative thinking. Certainly, some people are primed to be more creative than others. However, nearly every person is born with some level of creative skill and the majority of our creative thinking abilities are trainable.

Read more: Creativity Is a Process, Not an Event

3 Lessons on Creativity from Famous Creators

• The 15-Minute Routine Anthony Trollope Used to Write 40+ Books: Beginning with his first novel in 1847, Anthony Trollope wrote at an incredible pace. Over the next 38 years, he published 47 novels, 18 works of non-fiction, 12 short stories, 2 plays, and an assortment of articles and letters. Let’s break down why Trollope's simple strategy allowed the author to be so productive and how we can use it in our own lives.
• The Weird Strategy Dr. Seuss Used to Create His Greatest Work: In 1960, the founder of Random House publishing firm challenged Dr. Seuss to write an entertaining children’s book using only 50 different words. The result was a little book called Green Eggs and Ham. Here's what we can learn from Dr. Seuss…
• How Creative Geniuses Come Up With Great Ideas: Best-selling author Markus Zusak estimated that he rewrote the first part of his popular book “The Book Thief” 150 to 200 times. His work ethic and dedication tell us something crucial about how creative geniuses come up with great ideas.

You can also check out creativity articles about Albert Einstein, Martha Graham, George R.R. Martin, and Maya Angelou.

How to Be Creative

Step 1: Give yourself permission to create junk

In any creative endeavor, you have to give yourself permission to create junk. There is no way around it. Sometimes you have to write 4 terrible pages just to discover that you wrote one good sentence in the second paragraph of the third page.

Creating something useful and compelling is like being a gold miner. You have to sift through pounds of dirt and rock and silt just to find a speck of gold in the middle of it all. Bits and pieces of genius will find their way to you, if you give yourself permission to let the muse flow.

Read more: What Every Successful Person Knows, But Never Says

Step 2: Create on a schedule

No single act will uncover more creative genius than forcing yourself to create consistently. Practicing your craft over and over is the only way to become decent at it. The person who sits around theorizing about what a best-selling book looks like will never write it. Meanwhile, the writer who shows up every day and puts their butt in the chair and their hands on the keyboard — they are learning how to do the work.

If you want to do your best creative work, then don't leave it up to choice. Don't wake up in the morning and think, “I hope I feel inspired to create something today.” You need to take the decision-making out of it. Set a schedule for your work. Genius arrives when you show up enough times to get the average ideas out of the way.

Step 3: Finish something

Finish something. Anything. Stop researching, planning, and preparing to do the work and just do the work. It doesn't matter how good or how bad it is. You don't need to set the world on fire with your first try. You just need to prove to yourself that you have what it takes to produce something.

There are no artists, athletes, entrepreneurs, or scientists who became great by half-finishing their work. Stop debating what you should make and just make something.

Step 4: Stop judging your own work

Everyone struggles to create great art. Even great artists.

Anyone who creates something on a consistent basis will begin to judge their own work. I write new articles every Monday and Thursday. After sticking to that publishing schedule for three months, I began to judge everything I created. I was convinced that I had gone through every decent idea I had available. My most popular article came 8 months later.

It is natural to judge your work. It is natural to feel disappointed that your creation isn't as wonderful as you hoped it would be, or that you're not getting any better at your craft. But the key is to not let your discontent prevent you from continuing to do the work.

You have to practice enough self-compassion to not let self-judgement take over. Sure, you care about your work, but don't get so serious about it that you can't laugh off your mistakes and continue to produce the thing you love. Don't let judgment prevent delivery.

Step 5: Hold yourself accountable

Share your work publicly. It will hold you accountable to creating your best work. It will provide feedback for doing better work. And when you see others connect with what you create, it will inspire you and make you care more.

Sometimes sharing your work means you have to deal with haters and critics. But more often than not, the only thing that happens is that you rally the people who believe the same things you believe, are excited about the same things you are excited about, or who support the work that you believe in — who wouldn't want that? 

The world needs people who put creative work out into the world. What seems simple to you is often brilliant to someone else. But you'll never know that unless you choose to share.

Read more: Lessons on Sharing Your Gifts With the World From Someone Who Didn’t

How to Find Your Creative Genius

Finding your creative genius is easy: do the work, finish something, get feedback, find ways to improve, show up again tomorrow. Repeat for ten years. Or twenty. Or thirty.

Inspiration only reveals itself after perspiration.

The Science of Sleep: A Brief Guide on How to Sleep Better Every Night

If you want to learn how to sleep better, then you're in the right place. This guide will walk you through everything you need to know if you want to get better sleep. I'll explain the science of sleep and how it works, discuss why many people suffer from sleep deprivation without knowing it, and offer practical tips for getting better sleep and having more energy.

Plain and simple, the purpose of this guide is to explain the science of how to sleep better. You can click the links below to jump to a particular section or simply scroll down to read everything. At the end of this page, you’ll find a complete list of all the articles I have written on sleep.

I. The Science of Sleep

Sleep is one of the strangest things we do each day. The average adult will spend 36 percent of his or her life asleep. For one-third of our time on earth, we transition from the vibrant, thoughtful, active organisms we are during the day and power down into a quiet state of hibernation.

But what is sleep, exactly? Why is it so important and so restorative for our bodies and minds? How does it impact our lives when we are awake?

The Purpose of Sleep

Sleep serves multiple purposes that are essential to your brain and body. Let's break down some of the most important ones.

The first purpose of sleep is restoration. Every day, your brain accumulates metabolic waste as it goes about its normal neural activities. While this is completely normal, too much accumulation of these waste products has been linked to neurological disorders such as Alzheimer's disease.

Alright, so how do we get rid of metabolic waste? Recent research has suggested that sleep plays a crucial role in cleaning out the brain each night. While these toxins can be flushed out during waking hours, researchers have found that clearance during sleep is as much as two-fold faster than during waking hours.

The way this process occurs is fairly remarkable:

During sleep, brain cells actually shrink by 60 percent, allowing the brain's waste-removal system—called the glymphatic system—to essentially “take out the trash” more easily. The result? Your brain is restored during sleep, and you wake up refreshed and with a clear mind.

The second purpose of sleep is memory consolidation. Sleep is crucial for memory consolidation, which is the process that maintains and strengthens your long-term memories. Insufficient or fragmented sleep can hamper your ability to form both concrete memories (facts and figures) and emotional memories.

Finally, sleep is paramount for metabolic health. Studies have shown that when you sleep 5.5 hours per night instead of 8.5 hours per night, a lower proportion of the energy you burn comes from fat, while more comes from carbohydrate and protein. This can predispose you to fat gain and muscle loss. Additionally, insufficient sleep or abnormal sleep cycles can lead to insulin insensitivity and metabolic syndrome, increasing your risk of diabetes and heart disease.

How to Create a Chain Reaction of Good Habits

Human behaviors are often tied to one another.

For example, consider the case of a woman named Jennifer Dukes Lee. For two and a half decades during her adult life, starting when she left for college and extending into her 40s, Lee never made her bed except for when her mother or guests dropped by the house.

At some point, she decided to give it another try and managed to make her bed four days in a row—a seemingly trivial feat. However, on the morning of that fourth day, when she finished making the bed, she also picked up a sock and folded a few clothes lying around the bedroom. Next, she found herself in the kitchen, pulling the dirty dishes out of the sink and loading them into the dishwasher, then reorganizing the Tupperware in a cupboard and placing an ornamental pig on the counter as a centerpiece.

She later explained, “My act of bed-making had set off a chain of small household tasks… I felt like a grown-up—a happy, legit grown-up with a made bed, a clean sink, one decluttered cupboard, and a pig on the counter. I felt like a woman who had miraculously pulled herself up from the energy-sucking Bermuda Triangle of Household Chaos.” 

She was experiencing the Domino Effect.

What is the Domino Effect?

The Domino Effect states that when you make a change to one behavior it will activate a chain reaction and cause a shift in related behaviors as well. 

For example, a 2012 study from researchers at Northwestern University found that when people decreased their amount of sedentary leisure time each day, they also reduced their daily fat intake. The participants were never specifically told to eat less fat, but their nutrition habits improved as a natural side effect because they spent less time on the couch watching television and mindlessly eating. One habit led to another, one domino knocked down the next. 

You may notice similar patterns in your own life. As a personal example, if I stick with my habit of going to the gym, then I naturally find myself more focused at work and sleeping more soundly at night even though I never made a plan to specifically improve either behavior.

The Domino Effect holds for negative habits as well. You may find that the habit of checking your phone leads to the habit of clicking social media notifications which leads to the habit of browsing social media mindlessly which leads to another 20 minutes of procrastination.

In the words of Stanford professor BJ Fogg, “You can never change just one behavior. Our behaviors are interconnected, so when you change one behavior, other behaviors also shift.” 

Inside the Domino Effect

As best I can tell, the Domino Effect occurs for two reasons.

First, many of the habits and routines that make up our daily lives are related to one another. There is an astounding interconnectedness between the systems of life and human behavior is no exception. The inherent relatedness of things is a core reason why choices in one area of life can lead to surprising results in other areas, regardless of the plans you make.

Second, the Domino Effect capitalizes on one of the core principles of human behavior: commitment and consistency. This phenomenon is explained in the classic book on human behavior, Influence by Robert Cialdini. The core idea is that if people commit to an idea or goal, even in a very small way, they are more likely to honor that commitment because they now see that idea or goal as being aligned with their self-image.

Returning to the story from the beginning of this article, once Jennifer Dukes Lee began making her bed each day she was making a small commitment to the idea of, “I am the type of person who maintains a clean and organized home.” After a few days, she began to commit to this new self-image in other areas of her home.

This is an interesting byproduct of the Domino Effect. It not only creates a cascade of new behaviors, but often a shift in personal beliefs as well. As each tiny domino falls, you start believing new things about yourself and building identity-based habits.

The Rules of the Domino Effect

The Domino Effect is not merely a phenomenon that happens to you, but something you can create. It is within your power to spark a chain reaction of good habits by building new behaviors that naturally lead to the next successful action.

There are three keys to making this work in real life. Here are the three rules of the Domino Effect:

1. Start with the thing you are most motivated to do. Start with a small behavior and do it consistently. This will not only feel satisfying, but also open your eyes to the type of person you can become. It does not matter which domino falls first, as long as one falls. (For more on this, check out The Two-Minute Rule.)
2. Maintain momentum and immediately move to the next task you are motivated to finish. Let the momentum of finishing one task carry you directly into the next behavior. With each repetition, you will become more committed to your new self-image.
3. When in doubt, break things down into smaller chunks. As you try new habits, focus on keeping them small and manageable. The Domino Effect is about progress, not results. Simply maintain the momentum. Let the process repeat as one domino automatically knocks down the next.

When one habit fails to lead to the next behavior, it is often because the behavior does not adhere to these three rules. There are many different paths to getting dominoes to fall. Focus on the behavior you are excited about and let it cascade throughout your life.

If you want more practical ideas for breaking bad habits and creating good habits, check out my book Atomic Habits, which will show you how small changes in habits can lead to remarkable results. 

How to Unlock Your Hidden Creative Genius

This page pulls together my most essential information about creativity. I’ll share how creativity works, how to find your hidden creative genius, and how to create meaningful work by learning how to make creative thinking a habit. I’ve tried to present the basics of everything you need to know to start mastering creativity, even if you don’t have much time.

At the end of this page, you’ll find a complete list of all the articles I have written on creativity.

What is Creativity?

Let's define creativity.

The creative process is the act of making new connections between old ideas or recognizing relationships between concepts. Creative thinking is not about generating something new from a blank slate, but rather about taking what is already present and combining those bits and pieces in a way that has not been done previously.

While being creative isn't easy, nearly all great ideas follow a similar creative process. In 1940, an advertising executive named James Webb Young published a short guide titled, A Technique for Producing Ideas.

Young believed the process of creative connection always occurred in five steps.

The Creative Process

1. Gather new material. At first, you learn. During this stage you focus on 1) learning specific material directly related to your task and 2) learning general material by becoming fascinated with a wide range of concepts.
2. Thoroughly work over the materials in your mind. During this stage, you examine what you have learned by looking at the facts from different angles and experimenting with fitting various ideas together.
3. Step away from the problem. Next, you put the problem completely out of your mind and go do something else that excites you and energizes you.
4. Let your idea return to you. At some point, but only after you have stopped thinking about it, your idea will come back to you with a flash of insight and renewed energy.
5. Shape and develop your idea based on feedback. For any idea to succeed, you must release it out into the world, submit it to criticism, and adapt it as needed.

Motivation: The Scientific Guide on How to Get and Stay Motivated

Motivation is a powerful, yet tricky beast. Sometimes it is really easy to get motivated, and you find yourself wrapped up in a whirlwind of excitement. Other times, it is nearly impossible to figure out how to motivate yourself and you're trapped in a death spiral of procrastination. This page contains the best ideas and most useful research on how to get and stay motivated.

This isn't going to be some rah-rah, pumped-up motivational speech. (That's not my style.) Instead, we're going to break down the science behind how to get motivated in the first place and how to stay motivated for the long-run. Whether you're trying to figure out how to motivate yourself or how to motivate a team, this page should cover everything you need to know.

You can click the links below to jump to a particular section or simply scroll down to read everything. At the end of this page, you'll find a complete list of all the articles I have written on motivation.

What is Motivation?

So what is motivation, exactly? The author Steven Pressfield has a great line in his book, The War of Art, which I think gets at the core of motivation. To paraphrase Pressfield, “At some point, the pain of not doing it becomes greater than the pain of doing it.”

Common Misconceptions About Motivation

One of the most surprising things about motivation is that it often comes after starting a new behavior, not before. We have this common misconception that motivation arrives as a result of passively consuming a motivational video or reading an inspirational book. However, active inspiration can be a far more powerful motivator.

Common Misconceptions About Motivation

One of the most surprising things about motivation is that it often comes after starting a new behavior, not before. We have this common misconception that motivation arrives as a result of passively consuming a motivational video or reading an inspirational book. However, active inspiration can be a far more powerful motivator.

The work of top creatives isn’t dependent upon motivation or inspiration, but rather it follows a consistent pattern and routine. Here are some examples of how you can apply ritual and routine to get motivated:

• Exercise more consistently: Use the same warm up routine in the gym.
• Become more creative: Follow a creative ritual before you start writing or painting or singing.
• Start each day stress-free: Create a five-minute morning meditation ritual.
• Sleep better: Follow a “power down” routine before bed.

Mystery of how early animals survived ice age

Mystery of how early animals survived ice age

How did life survive the most severe ice age? A McGill University-led research team has found the first direct evidence that glacial meltwater provided a crucial lifeline to eukaryotes during Snowball Earth, when the oceans were cut off from life-giving oxygen, answering a question puzzling scientists for years.

In a new study published in the Proceedings of the National Academy of Sciences, researchers studied iron-rich rocks left behind by glacial deposits in Australia, Namibia, and California to get a window into the environmental conditions during the ice age. Using geological maps and clues from locals, they hiked to rock outcrops, navigating challenging trails to track down the rock formations.

By examining the chemistry of the iron formations in these rocks, the researchers were able to estimate the amount of oxygen in the oceans around 700 million years ago and better understand the effects this would have had on all oxygen-dependent marine life, including the earliest animals like simple sponges.

"The evidence suggests that although much of the oceans during the deep freeze would have been uninhabitable due to a lack of oxygen, in areas where the grounded ice sheet begins to float there was a critical supply of oxygenated meltwater. This trend can be explained by what we call a 'glacial oxygen pump'; air bubbles trapped in the glacial ice are released into the water as it melts, enriching it with oxygen," says Maxwell Lechte, a postdoctoral researcher in the Department of Earth and Planetary Sciences under the supervision of Galen Halverson at McGill University.

Around 700 million years ago, the Earth experienced the most severe ice age of its history, threatening the survival of much of the planet's life. Previous research has suggested that oxygen-dependent life may have been restricted to meltwater puddles on the surface of the ice, but this study provides new evidence of oxygenated marine environments.

"The fact that the global freeze occurred before the evolution of complex animals suggests a link between Snowball Earth and animal evolution. These harsh conditions could have stimulated their diversification into more complex forms," says Lechte, who is also the study's lead author.

Lechte points out that while the findings focus on the availability of oxygen, primitive eukaryotes would also have needed food to survive the harsh conditions of the ice age. Further research is needed to explore how these environments might have sustained a food web. A starting point might be modern ice environments that host complex ecosystems today.

"This study actually solves two mysteries about the Snowball Earth at once. It not only provides explanation for how early animals may have survived global glaciation, but also eloquently explains the return of iron deposits in the geological record after an absence of over a billion years," says Professor Galen Halverson.

About the study

"Subglacial meltwater supported aerobic marine habitats during Snowball Earth" by Maxwell Lechte, Malcolm Wallace, Ashleigh van Smeerdijk Hood, Weiqiang Li, Ganqing Jiang, Galen Halverson, Dan Asael, Stephanie McColl, and Noah Planavsky is published in Proceedings of the National Academy of Sciences of the United States of America. The paper is a collaboration between McGill University, University of Melbourne, Nanjing University, University of Nevada, Las Vegas, and Yale University.

This work received financial support from the Australian Government Research Training Program Scholarship, the Albert Shimmins Award, the Australian Research Council Discovery Grant, the NASA Astrobiology Postdoctoral Fellowship, the Puzey Fellowship, and the Australian Research Council.

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Materials provided by McGill University. Note: Content may be edited for style and length.