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When glacial ice sheets melt, something counterintuitive happens to sea levels. Logic might suggest that nearby levels would rise, but instead they fall. Thousands of miles away, however, they do go up in a kind of seesaw effect. Why? The answer is that water disperses away owing to the loss of gravitational pull toward the ice sheet.
The patterns of how that happens are called sea level fingerprints, since each incidence is unique. Elements of the concept — which lies at the heart of the understanding that global sea levels don’t rise uniformly — have been around for more than a century, and modern sea level science has been built around it. But there’s long been a knowledge gap in the widely accepted theory. A sea level fingerprint has never definitively been detected by researchers.
A team of scientists — led by Harvard alumna Sophie Coulson and including Harvard geophysicist Jerry X. Mitrovica — believe they have detected the first. The findings are described in a new study published Thursday in Science. The work validates almost a century of sea level science and helps solidify confidence in models predicting future changes, projections that have grown more important on the warming planet.
“Ocean level projections, urban and coastal planning — all of it — has been built on the idea of fingerprints,” said Mitrovica, the Frank B. Baird Jr. Professor of Science in the Department of Earth and Planetary Sciences. “That’s why fingerprints are so important. They allow you to estimate what the geometry of the sea level changes is going to be like … so we now have much more confidence in how sea level changes are going to evolve. … If fingerprint physics wasn’t correct, then we’d have to rethink all modern sea level research.”
Sea level fingerprints have been notoriously difficult to track because of the major fluctuations in ocean levels brought on by changing tides, currents, and winds. That presents researchers with the challenge of trying to detect millimeter level motions of the water and link them to melting glaciers thousands of miles away.
Mitrovica compared the search to the one for the subatomic particle the Higgs Boson.
“Almost all physicists thought that the Higgs existed, but it was nevertheless a transformative accomplishment when it was firmly detected,” Mitrovica said. “In sea level physics, almost everyone assumed that the fingerprints existed, but they had never been detected at a comparable level of confidence.”
The new study uses newly released satellite data from a European marine-monitoring agency that captured more than 30 years of observations around the Greenland Ice Sheet and much of the ocean close to Greenland to capture rising and falling ocean levels from the fingerprint.
The satellite data caught the eye of Mitrovica and colleague David Sandwell of the Scripps Institution of Oceanography. Typically, records from this region had only extended up to the southern tip of Greenland, but in this new release the data reached 10 degrees higher in latitude, allowing the scientists to eyeball a potential hint of the seesaw caused by the fingerprint.
Mitrovica quickly turned to Coulson, a former doctoral student in his lab and now a postdoctoral fellow at Los Alamos National Laboratory, to verify whether this was truly the fingerprint signal sea level scientists had been chasing for decades.
“She was the best person to … accurately model what the fingerprint would look like given our understanding of how the Greenland Ice Sheet has been losing mass, and she could establish whether that prediction matched the satellite observation,” Mitrovica said.
Coulson, an expert in modeling sea level change and crustal deformation associated with melting ice sheets and glaciers, was visiting family in the U.K. when the data sets hit her inbox. She immediately recognized the potential, she said.
Coulson quickly collected three decades worth of the best observations she could find on ice height change within the Greenland Ice Sheet as well as reconstructions of glacier height change across the Canadian Arctic and Iceland. She combined these different data sets to create predictions for the region from 1993 to 2019, which she then compared with the new satellite data. The fit was perfect: a one-to-one match that showed with more than 99.9 percent confidence that the pattern of sea level change revealed by the satellites is a fingerprint of the melting ice sheet.
“I was completely amazed. There it was — a sea level fingerprint, proof of their existence,” Coulson said. “This was a really, really exciting moment for all of us. There are very few moments in science which provide such simple, remarkable clarity on complex Earth processes.”
“This work, led so remarkably by Sophie, is one of the highlights of my career, a bookend to all the theoretical and computational work we’ve built with a community of international colleagues,” added Mitrovica, whose group was the first to present models and predictions of what sea level fingerprints should look like.
In scientific research it usually takes years to develop results and then draft a paper, but here the researchers were able to act quickly. In total, the process took only a few months from when they saw the satellite data to when they submitted the piece.
That’s because much of the theory, technology, and methods had already been well developed and refined since Mitrovica and his team presented their work on sea level fingerprints about 20 years ago — computations that were widely accepted and have been factored into almost all models predicting sea level rise.
Now that the first sea level fingerprint has been detected, the question with the biggest global implications is where it all leads.
“More detections will come,” Mitrovica said. “Soon the full power of fingerprint physics will be available to project sea level changes into the next decade, century, and beyond.”
This work was partially supported by theStar-Friedman Challenge for Promising Scientific Research, the John D. and Catherine T. MacArthur Foundation, and the Los Alamos National Laboratory Director’s Postdoctoral Fellows Program.
Sometimes getting to where you want to go is a matter of finding the right guide.
Four teams of researchers, led by Harvard Forest ecologists, searched for a patch of ancient trees deep in the woods of western Pennsylvania this summer as part of a project to study how climate changes affected trees over the centuries. One of the scientists had come across them 40 years earlier, but they appeared to have vanished. Just as the group was about to give up and move on they came across someone who gave them a valuable clue.
“When he jumped out of his Jeep to greet us, we were about to plunge into another forest that was at least three-quarters or a mile away,” said Neil Pederson, a senior ecologist and co-manager of the Tree Ring Lab at the Harvard Forest. The Jeep driver, a husky man with fluffy silver hair, tipped them to a clump of scraggly-looking eastern hemlocks. Several hours later, “We’d finally found them,” Pederson said.
That day’s search was part of the lab’s ambitious project to find and core the oldest trees in the Northeast. Studying the color and size of their rings offers scientists a glimpse into the past, allowing them to see how trees and forests responded to extreme climate events, like droughts or late-spring frosts in the past. They then use that data to map the long-term development of these forests and model the future impact on their health from climate-related weather events, which are growing harsher as the planet warms.
“Large-scale forest disturbances may represent the kind of extreme climate events that we expect to see increase with climate change, so understanding more about their frequency in the past could help to inform how far things are moving from baseline,” said Laura Gayle Smith, a research assistant at the Harvard Forest, who works as a member of the Tree Ring Lab. “The common framework for temperate forests is that they are basically in equilibrium over large scales and somewhat agnostic to climate. Small disturbances happen at the individual-tree-to-stand level, but overall, the composition remains very stable over long periods of time — centuries to millennia.”
“We use tree cores to extract what I’ve been leaning toward calling the memory of the tree,” said Neil Pederson in the lab alongside core samples.
About a decade ago, Pederson and David Orwig, a senior forest ecologist and the co-manager of the Tree Ring Lab, showed this isn’t always the case. They presented evidence that droughts and harsh spring frosts from 250 years ago affected different forests across hundreds of miles in the Southeast. The disturbances abruptly killed some trees but accelerated the growth of others.
“This study will hopefully give us more insight about that relationship between climate events and forest disturbance so that we can better predict forest response under different climate scenarios,” Gayle Smith said.
For that, the lab seeks guidance from tree rings. The rings, which look a bit like the concentric circles on a dart board, indicate the age of a tree and give hints of what it’s endured. The greater the number of annual rings, the older the tree. Light-colored ones represent years of extreme cold. Wafer-thin wood indicates dry conditions and stymied tree growth.
“We use tree cores to extract what I’ve been leaning toward calling the memory of the tree,” said Pederson. “When a drought arrives, when a hurricane arrives, when fire arrives, or an ice storm or insects, trees can’t run and hide like we can or like other animals can. They take these events, these abuses of time, and they get recorded in their rings, and we can extract that information and learn about anything.”
The first step to this science, called dendrochronology, is getting samples of the rings. For researchers, that often involves driving along dirt roads, walking beneath miles of foliage, and up and down hillsides.
To core the trees, the researchers primarily use increment borers, tools that look like a cross between a drill and a screw. They must be manually twisted through the bark and into its core. As it twists out it extracts pencil-size slivers of the tree ring.
“The borer gets much harder to turn as you drill into the tree, and sometimes will get stuck on the way out so you have to put your body weight into pulling backwards while turning,” Gayle Smith said. “I always tell people that between hiking into the sites and then coring trees it’s a full-body workout. It can really tear your hands up.”
Coring leaves a wound in the tree but doesn’t fatally injure it. The entire process takes between two and three hours. Besides taking samples, scientists jot down visual markings on the trees and demarcate a plot that has a 20-meter radius.
The researchers plan to core between 2,500 and 3,500 trees in 35 forests. The field work is part of a four-year project funded by the National Science Foundation, and kicked off this summer with visits to 15 forests. So far, the group has traveled to forests in Pennsylvania, New York, Maine, and New Jersey. The group will eventually amass 600 years of tree growth data.
Kicking off fieldwork for a dream project: studying the long-term development, synchronicity, & ecological memory in old-growth forests of the Northeastern US. First days in the southern Adirondacks pic.twitter.com/OiZ2qrNxqf
The researchers venture out in full hiking gear and backpacks filled with supplies. The coring equipment adds about 40 pounds.
“One time I got back from a trip on a Wednesday, but I felt like my body didn’t arrive till the Sunday,” Pederson said.
Lab members, who also includes two summer research assistants, refer to the project as a nature lover’s dream and an honor.
When out in the field the scientists get used to sweeping views of landscapes, rock formations, and sunsets. They see wildlife, sometimes doing peculiar things. In June, for example, the team saw a black rat snake scale a thick sugar maple tree in Ricketts Glen, Pennsylvania.
The forest is also a humbling place to work, especially for experts who know what it should look like.
“Each forest we visited had lost or was in the process of losing an overstory tree species due to an introduced disease or insect,” Orwig said. “A few forests lost two species and one was in the process of losing a third. So even these forests, which have been the least directly disturbed by humans over the last few centuries, are being indirectly impacted in a big way.”
Harvard’s Tree Ring Lab sits inside a repurposed garage on the edge of the Harvard Forest in Petersham, Massachusetts. Collections of the extracted wood slivers fill stacks of boxes while larger tree stumps that show the full rings are piled in corners. The lab has a pleasant woody, earthy smell.
The samples are painstakingly made smooth with a belt sander, then by hand sanding. “It’s a long process sometimes, particularly for species where the ring boundaries aren’t very apparent,” Gayle Smith said. “We have to get them sanded down to the point that we can see the cellular structure.”
The samples then go under a high-powered microscope, which digitizes the data.
The ancient eastern hemlocks that took them hours to find, for example, showed that the two oldest trees traced to 1490. They all lived through the 1500s and 1600s — two periods with severe, prolonged drought. The trees survived the so-called 16th century megadrought, which affected an area that extended from portions of Mexico to much of the continental U.S., including Boston. It likely slowed the growth of these trees, which were smaller than most. The trees also showed signs from the Year Without a Summer in 1816 when a massive volcanic eruption in Indonesia triggered unusually cold, wet conditions across Europe and North America.
“I feel very lucky to be on this project as we get to visit, sample, and learn from centuries-old trees,” said Orwig. “These forests are truly magical places. … There is a sense of awe I get knowing that the forests we are investigating have been there for hundreds of years and are now revealing clues to past climate, disturbance, and environment.”
In one of the more unusual scientific career pivots you’re likely to hear about, Randall Munroe has parlayed his physics degree and experience working at NASA on computers and robots into fame as a cartoonist, blogger, and author. Munroe applies serious science to outrageous scenarios — “What if you built a billion-story building?” — and patiently explains the science behind the often-disastrous consequences. On Tuesday, Munroe visits Sanders Theatre to discuss the second book in his “What If?” series in an event sponsored by Harvard Book Store, Harvard Library, and the FAS Division of Science. He spoke with the Gazette about the humor in science, why kids ask better questions than adults, and whether his curiosity will ever run dry. The interview has been edited for clarity and length.
Q&A
Randall Munroe
GAZETTE: Do you remember when you first thought that science might be funny?
MUNROE: I’ve just always found that stuff in general is funny. And the more I got interested in science, the more of the stuff I thought was funny showed up there. When I was a little kid, a big influence on me was the PBS show “Square One,” which was like a variety sketch comedy show around teaching kids math. I rewatched some of it recently and it was incredibly sharp. A lot of jokes I didn’t even get at the time. There’s funny stuff in whatever topics people get really interested in.
GAZETTE: Your approach marries the absurd to the serious. How did you come up with that formula?
MUNROE: Well, the equations are the same whether you’re talking about something deadly serious or something ridiculous. If you’re trying to learn the equations, why not apply them to something vivid and memorable and interesting? I always had a much easier time learning math when it was being applied to a problem whose answer I was interested in — that meant something to me, and I could picture. You say “There’s a 5-meter ball rolling down an inclined plane with this many degrees and that has this rotational inertia. Figure out how quickly it’ll accelerate.” That sounds boring to me. But if you ask, “Could Indiana Jones really have outrun that boulder?” It’s the same problem, but suddenly you’re like, “Well, I could watch the movie and see how long the chute is. What is the slope?” You could do those calculations and figure out would he have been smushed or not.
GAZETTE: Have you ever done the Indiana Jones calculation?
MUNROE: I haven’t. My guess is that probably the shots are stitched together. I haven’t seen that movie in a while, and now I’m trying to decide how much would the irregularity of the track contribute to rolling resistance. I think not much once it gets going, that’s got to be a heavy boulder. I think that it would need a fairly big vertical drop early on to catch up to a person sprinting. People running can accelerate really fast. This is why I’ve loved doing “What If?” Whenever someone asks me a question like this, I describe it like getting a song stuck in your head. The moment I mentioned the boulder, in the back of my mind, I’m thinking, “Could you do that calculation? Are there enough clips? Is there an in-between part where it cuts and you’re like, ‘Oh, I can’t tell how far it rolled down’?” Or maybe you’d go and watch “Indiana Jones” and find that the boulder changes speed in ways that imply there’s unknown stuff happening in the middle so you just can’t solve it. But that’s what I like about these questions. People will send me a question and even if I wasn’t writing a book, I would still feel, “Now I can’t rest until I figure out whether this person is right. Would they be launched into the air by Old Faithful or just burned?”
GAZETTE: You’ve been quoted as saying that children tend to come up with the best questions. Why?
MUNROE: I don’t think that they’re more creative or better at coming up with questions. My sense — and I could be wrong — is that it’s that adults are more reluctant to ask good questions. When you’re an adult, you’re supposed to know how everything works, so anytime you’re asking a question like this, you’re potentially revealing your own ignorance. So, adults will often frame the question in a way that shows they’re asking about something really smart. A kid has no awareness. They’re just constantly asking, “Hey, why are cars like that?” “Why is that over there?” Everything’s new to them, so they have no filter.
GAZETTE: What’s your research process like and at what point do you have to call on experts?
MUNROE: I want to know the answer. That’s the thing that’s driving me most of the time. So, whenever I go to an expert, it’s because I’ve failed in my attempts to solve it myself and the fastest way to get to the answer is to swallow all of my Millennial reluctance and make a phone call or send an email. I’ll try everything I can think of. One of the things about being given a question that might not have an answer to is it’s not like there’s one method that’s going to get you the solution. So I just think, “What do I know about this topic? What is something that could help give the solution?” And then, “What are some intermediate steps that could get me closer?” And then, “If I have this number, then I just need this other number and then I could get a step closer to the solution.” Then I have to figure out, where do you get that number?
GAZETTE: Are you ever afraid you’re going to run out of questions?
MUNROE: Oh, God, I think probably in the first 12 hours of running my website, I had more questions than I could answer in a lifetime. But no, one of the nice things is they’re always making new stuff in the world. There are always new things that I don’t understand, and those are things that you can ask questions about and I’ll be interested in the answer.
Harvard University and Amazon Web Services (AWS) on Monday launched a strategic alliance to advance fundamental research and innovation in quantum networking.
This effort provides significant funding for faculty-led research at Harvard and will build capacity for student recruitment, training, outreach, and workforce development in this key emerging technology field. The initiative focuses on driving rapid progress toward specific research aims in quantum networking at the Harvard Quantum Initiative (HQI).
Through a three-year research alliance, enabled by Harvard’s Office of Technology Development, AWS will provide support of faculty-led and designed research projects at HQI in quantum memories, integrated photonics, and quantum materials. The principal goal of the research projects is to develop foundational methods and technologies for what eventually will become a quantum internet.
Separate philanthropic support from AWS will help Harvard train and support graduate students and postdoctoral researchers, especially with the goal of welcoming aspiring scientists and engineers from underrepresented backgrounds.
“By working together, academia and industry can accelerate discovery and technological progress,” said Harvard Provost Alan M. Garber. “Through this alliance with AWS, we will bring scientific scholarship and education to bear on some of the most exciting frontiers in quantum science. Together we will advance the goals of the Harvard Quantum Initiative, an interfaculty initiative that exemplifies the rewards of collaboration across different scientific domains.”
“Quantum networking is an emerging space with promise to help tackle challenges of growing importance to our world, such as secure communication and powerful quantum computing clusters,” said Antia Lamas-Linares, quantum networking lead at AWS. “The collaborative initiative between AWS and Harvard will harness top research talent to explore quantum networking today and establish a framework to develop the quantum workforce of the future.”
A portion of the funding will also allow an upgrade to the quantum fabrication capabilities of the NSF-supported Center for Nanoscale Systems at Harvard, a critically important facility for nanofabrication, materials characterization, soft lithography, and imaging, with locations in Cambridge and at the Science and Engineering Complex in Allston.
These efforts build upon rising momentum. Harvard announced last year a new Ph.D. program in Quantum Science and Engineering, and is finalizing plans to comprehensively renovate an existing campus building into a new physical home for HQI, as well as a quantum hub, a project made possible by gifts from Stacey L. and David E. Goel ’93 and several other alumni.
The Gazette spoke to the four faculty members leading the projects that make up the research alliance: HQI codirector Evelyn Hu, the Tarr-Coyne Professor of Applied Physics and Electrical Engineering; Marko Lončar, Tiantsai Lin Professor of Electrical Engineering; Mikhail Lukin, the George Vasmer Leverett Professor of Physics and co-director of HQI; and Hongkun Park, Mark Hyman Jr. Professor of Chemistry. They spoke about the research at the center of the initiative, how it will help students, and how it builds on a long history of advances at Harvard. The interview has been edited for clarity and length.
Q&A
Evelyn Hu, Marko Lončar, Mikhail Lukin, and Hongkun Park
GAZETTE: This is an exciting alliance between HQI and AWS. What does it represent for the study of quantum science and why is important?
HU: First, with quantum much of our study is still rooted in understanding the fundamentals, the basic science — the chemistry, the physics, the engineering — to understand what it’s all about. Yet, at the same time, we have this incredible opportunity, realizing that there are applications that are making their way to the commercial world. This alliance with AWS allows us to seamlessly bridge the fundamentals in diverse areas, more typical of an academic environment, informed by the understanding of where the applications are, and how to make those applications actually emerge from the fundamentals. This is done in concert with those who understand those applications and what it means to take the science, engineering, and technology into the commercial sector, and therefore into society. So, the alliance represents an unprecedented opportunity for all of us in the University, and particularly for our students, to gain this perspective and to gain this opportunity.
GAZETTE: Speaking of students, what specifically is critical about training what’s being called “Generation Q”?
PARK: This type of work requires a truly interdisciplinary collaboration among scientists and technologists of different expertise. It also represents a relatively rare — but soon to be much more common — collaboration between academia and industry. As such, it provides unique yet fertile educational grounds for students.
HU: Given the broad scope of the foundational platforms that are yet to be constructed, the very different nature of quantum information, and the spanning of the distance to systems and applications, training Generation Q requires a substantial marshaling of very diverse talents, interests, expertise, a rewriting of the foundational education and training rules. New types of industrial-academic collaborations are also critical to span fundamentals to systems: Students should have the opportunity to participate in collaborations, and to directly understand the different expertise, points of view, and “give and take” that are needed.
LONČAR: In my opinion, we are witnessing the birth of a new scientific discipline — quantum engineering. This is similar to the situation many moons ago when electrical engineering was born out of physics, for example. Industrial relationships like the one we are developing with AWS are crucial for training a new generation of engineers.
GAZETTE: Does the alliance advance how academia and industry work together, especially in this region?
LUKIN: Initiatives of this kind — bridging cutting-edge academic research and leading industry partners — are critical to the emergent quantum industry and quantum ecosystem in the U.S. as a whole and in the Boston area specifically. We believe that the Boston area, with academic institutions such as Harvard and MIT, and a range of startups in the quantum domain, already plays a leading role in worldwide quantum effort, and we view such partnerships as being essential for the continued leadership in this area.
GAZETTE: The projects fall into three areas: quantum memories, integrated photonics, and quantum materials. What is your goal here?
PARK: Our main goal is to realize the promise of quantum repeaters, which is the backbone of the quantum internet. In the quantum internet, communication will be performed using individual photons that cannot be copied or amplified due to their quintessential quantum nature. One of the issues is that individual photons will get lost, even within the optical fibers, within about 100 kilometers or 200 kilometers. So, every 100 kilometers or so, we either need to convert individual photons to classical information or somehow “repeat” them without really measuring them. Quantum repeaters that Misha’s [Mikhail’s] group is developing provide a solution to this problem.
Marko’s team is performing another very critical task of linking quantum repeaters to the existing optical fiber network we use today. To do that, you have to change the wavelength of the photon from optical to telecom range.
Evelyn and I are working on exploring new materials for the next generation’s quantum repeaters, so that we can make them work at elevated temperatures, instead of the extremely low temperatures that we are currently working in.
HU: Part of the goal in linking these project areas is ultimately the creation of a system. This systems-based approach is rarely carried out in universities. We need the resources, the longevity, the knowledge of external markets and societal demands. This new collaboration provides that complement.
GAZETTE: What is the quantum internet? What can it do?
LONČAR: One feature is security of information, because the shuttling of quantum states means you can detect the presence of any eavesdropper. The second is coherence, basically a way to access quantum computers — once they become ready for primetime — in completely quantum fashion. For example, this could allow a user to generate a complex quantum state, send it via quantum internet — along with the quantum algorithm — to the quantum computer, do computation, and then retrieve the quantum state that is the result of the computation. Such an end-to-end quantum system — “quantum cloud,” as I like to call it — would result in unprecedented computational power and security.
GAZETTE: Could the quantum internet be as profound an advance as the internet?
HU: My belief is that the advances provided by a quantum internet will be truly profound, in ways that we cannot, at the moment, anticipate. In general, humans have always been limited in our ability to realize or predict the implications of a new technology: Early on, no one quite knew what to do with transistors. Who knew what profound changes the personal computer or the smartphone would create? Similarly, what might we be able to do if we were able to send, receive, process and store information far more quickly and securely than we currently can? Would we multitask, integrate ever more sensors to seamlessly project different visions of the real world?
PARK: In my mind, the first real-world application of the quantum internet is genuinely secure, unhackable communication. As Evelyn said, like other profound technological developments, it’s anybody’s guess exactly how things will unfold after.
LUKIN: We are talking here about not just the next generation of internet, but about the internet with fundamentally new capabilities. Apart from secure communication, applications could include networked quantum computers with fundamentally new possibilities. One example is “blind” quantum computing where computation can be executed on a quantum cloud without anybody — including parties running the cloud — having a possibility to find out what is being computed, new types of distributed sensor networks, secure voting and decision-making, and more.
This is an inflection point, where a new scientific field is being born, involving the interface between quantum physics, chemistry, computer science, and device engineering. Analogies from the past include the emergence of new fields such as electrical engineering or computer science. They emerged from disciplines such as physics or mathematics and both had a profound impact on science and society.
GAZETTE: This alliance builds on fundamental work that has been done at Harvard for decades. Can you give us some examples of this history?
LUKIN: If we go back as far as the 1950s and 1960s, important foundational work has been done both in terms of understanding quantum properties of light, how to think about them, how to describe them, what does it mean for that light to be quantum. That was foundational work done by Roy Glauber, a Nobel laureate. In parallel, there has been also some truly foundational work by Ed Purcell, another Harvard physics professor and another Nobel prize winner, involving the interaction of radiation with matter. That resulted in something which is called the Purcell effect, which is actually the phenomenon we use to make single photons interact strongly with single atoms.
About 20 years ago, another breakthrough happened at Harvard: Together with several collaborators around the world, we theoretically developed the idea of quantum repeaters — the basic building blocks of quantum internet that can correct errors in quantum transmission. That included a conceptual way to build quantum repeaters using memories and also specifically ideas on how to use atom-like impurities in diamonds to build them in practice. Later we carried out early work on manipulating individual, atom-like defects in diamonds. Very soon we realized that in order to make these things practical someday, we not only needed basic physics, but we also needed chemistry, photonic engineering, material science. This is how this collaboration between our various groups started. Another very important breakthrough happened in Marko’s group when they developed a technique to make nanoscale devices out of diamond — something that was completely impossible previously. This was essential for realizing the practical quantum network nodes that we eventually demonstrated in our laboratories. And from that, Marko’s team realized that that the best approach was to try to make small nanoscale devices out of diamond.
So, it’s been decades of work, starting from very basic things like understanding the fundamental interactions between single atoms and single photons, to much more practical questions about how to make these completely futuristic devices — two decades ago, it was totally unthinkable that we could make any devices out of diamond.
Where we are now is a result of several kinds miracles, some minor and some major. What we want to do now is to really take these building blocks and start making devices and combine them into systems, as Evelyn said, systems that will have capabilities that are completely unprecedented.
HU: Misha said it’s a series of miracles. Science is always miraculous, but I think it’s more than that. I think it’s long-term commitment. What Misha describes — going back into the 1950s and certainly more recently — is playing the long game, the commitment to possibilities, and to working with people, even at early stages, when possibilities are not yet fully understood, much less realized. It’s only by taking that long view, making a commitment to collaboration — and the underlying trust that holds collaborations together — that the miracles actually manifest themselves.
More people are bitten by other people on the New York City subway than by sharks in the ocean. Flowerpots, tumbling from windowsills, kill more humans than sharks do. So do selfies: You should be more scared of falling off a cliff on your quest for a perfect photo than of a shark attack.
“Not only are sharks not bad. They’re actively good,” said David Shiffman, a marine conservation biologist at Arizona State University. Last week, the Harvard Museums of Science and Culture invited Shiffman to give a talk on his new book, “Why Sharks Matter: The Science and Policy of Saving Sharks.” In both, Shiffman explained why he adores these oft-feared creatures, and how we can help save them from extinction.
“I’ve loved sharks for a very long time,” said Shiffman, who wore a shirt that read, “Respect the locals” with “respect” spelled out in tiny sharks. Shiffman said that about a third of today’s 538 known shark species are considered at risk of extinction. And humans, he said, are by far their No. 1 threat. Overfishing — accidentally or on purpose — is dwindling their numbers, but so is human-induced climate change, which is causing rapid shifts in their ocean habitats.
“Shark attacks are unbelievably rare and unlikely,” said David Shiffman, author of “Why Sharks Matter: The Science and Policy of Saving Sharks.”
Photo by Scott Eisen
“They’ve had a tough time in the last few years,” said George Lauder, the Henry Bryant Bigelow Professor of Ichthyology at Harvard. Sharks face a warming ocean, ocean acidification, loss of prey, and many more dire challenges, Lauder said in his introductory remarks.
“This is bad news, but it’s not a lost cause,” Shiffman said. “We can help sharks.”
But why should we? The greatest reason, by far, is that sharks are critical cogs in ocean ecosystems, Shiffman said. Ocean food webs are complex and vulnerable; removing a predator can have disproportionate impacts, potentially causing the whole system to unravel. Sharks also have unusual biology and abilities. Their skeletons are built from cartilage, not bone, which may help them heal faster. (Try to bend your forearm, Shiffman said to his audience. Then crinkle your ears. That’s the difference between bone and cartilage).
Sharks’ vision and sense of smell are better than humans’, and they have a sense we lack: Because sharks can detect electromagnetic fields, they can spot prey hidden under the sand by sensing the electricity in their beating hearts. The hammerhead shark’s long, flat head is like a metal detector, designed to scan the seabed for heartbeats instead of lost coins. Sharks also use the Earth’s magnetic field to navigate from a favorite beach to a specific island without getting lost at sea.
In addition, many species possess other useful traits. Some have biofluorescent mouths, which lure prey to swim right in. (“That is snack time goals,” Shiffman said.) Some glow in the dark. The goblin shark can hyperextend its jaw to better gobble up prey. The thresher shark uses its tail like a whip, making a shock wave that stuns its food. And the Greenland shark eats polar bears and can live for more than 400 years.
“You often think of sharks as being fast and powerful,” said Shiffman. But his favorite shark, the sandbar shark, is slow and lazy. Many misconceptions, he said, can be tied to Steven Spielberg’s “Jaws,” which portrayed sharks as evil monsters that hunt humans. “Spielberg has a lot to answer for,” Shiffman said. “Shark attacks are unbelievably rare and unlikely.” About 38 percent of reported shark attacks in Australia are false, he said.
Shiffman wrote his book to dispel these misconceptions and offer practical ways people can help save sharks. Some who want to help, he said, are doing more harm than good. Groups of people Shiffman calls “macho cowboy idiot scuba divers” take photos of themselves riding, hugging, and kissing sharks on the face. “Don’t do that,” Shiffman said.
During the question-and-answer portion of the talk, viewers as young as 4 years old asked why some sharks are bubble-gum pink (the answer: they live where light can’t reach, so that hue makes them near-invisible) and whether shark-deterrence technologies actually work. “The most charitable thing I can say is that some of them work sometimes under certain conditions,” Shiffman said.
One audience member asked whether Shiffman took a dip off Cape Cod, where he’d given a book talk the week prior. Shiffman responded with an anecdote: He was standing on a beach with a colleague who pointed to a spot where the ocean turned from light brown to black, the mark of a sharp drop-off. See that spot? His colleague asked. We have a sensor there that detected an adult great white shark out there 99 percent of last week.
“So, yeah,” Shiffman said. “I didn’t go swimming.”
What if emergency medical personnel could treat a desperately ill patient in need of oxygen with a simple injection instead of having to rely on mechanical ventilation or rush to get them onto a heart-lung bypass machine?
A new approach to transporting gases using a class of materials called porous liquids represents a big step toward artificial oxygen carriers and demonstrates the immense biomedical potential of these unusual fluids.
In a study published last month in Nature, a team of scientists in Harvard’s Department of Chemistry and Chemical Biology detail a new approach to transporting gases in aqueous environments using porous liquids. The authors identified and tailored multiple porous frameworks that can store much higher concentrations of gases, including oxygen (O2) and carbon dioxide (CO2), than normal aqueous solutions. This breakthrough may hold the key to creating injectable sources of oxygen as a bridge therapy for cardiac arrest, creating artificial blood substitutes, and overcoming longstanding challenges in preserving organs for transplants.
“We realized that there would be a lot of benefits to using liquids with permanent microporosity to address gas-transport challenges in water and other aqueous environments,” said Jarad Mason, the paper’s senior author and assistant professor of chemistry and chemical biology. “We’ve designed fluids that can transport O2 at densities that exceed that of blood, which opens up exciting new opportunities for transporting gases for a variety of biomedical and energy applications.”
The design allows the internal surface to be water-repelling and the external surface to be water-loving, “because otherwise the fluid would phase separate like oil and water,” explained Daniel P. Erdosy (left), who met with Joy Cho, Jarad Mason, and Malia Wenny in the Mallinckrodt Chemistry Laboratory.
Liquids with permanent microporosity are a new class of materials that are composed of microscopic porous particles dispersed in a liquid medium. Imagine tiny, recyclable, sponge-like bits capable of soaking up gases in their holes and releasing them. Until now, all porous liquids have consisted of microporous nanocrystals or organic cage molecules dispersed in organic solvents or ionic liquids that are too large to diffuse through the pore entrances. The researchers developed a new strategy to create aqueous porous liquids — termed “microporous water” — with high gas capacities based on thermodynamics.
The work was led by members of Mason’s lab, including doctoral students Daniel P. Erdosy, Malia Wenny, Joy Cho, Miranda V. Walter, postdoctoral researcher Christopher DelRe, and undergraduate Ricardo Sanchez. Computational simulations and biological experiments were also performed in collaboration with scientists at Boston Children’s Hospital and Northwestern University, including Felipe Jiminez-Angeles, Baofu Oiao, and Monica Olvera de la Cruz.
Water is a polar molecule, making it a great solvent for other polar molecules such as ethanol and sugar, but it is much worse at dissolving non-polar molecules like O2 gas. As such, pure water can carry 30 times less oxygen than red blood cells. The extremely low solubility of gases in water has imposed a hard limit on many biomedical and energy-related technologies that require the transport of gas molecules through aqueous fluids. This new mechanism for gas transportation overcomes the low solubility of gases in water and enables rapid gas transport.
The researchers suspended microporous nanocrystals in water and other aqueous solutions. Courtesy of Jarad Mason
Inspired by pores in certain proteins that are accessible to water molecules but overall remain dry in aqueous solutions, the team proposed that microporous nanocrystals with hydrophobic internal surfaces and hydrophilic external surfaces could be designed to leave the microporous framework permanently dry in water and available to absorb gas molecules.
“We had to reconcile two seemingly contradictory properties,” Erdosy said. “We designed the internal surface to be hydrophobic and water-repelling, and the external surface to be hydrophilic and water-loving, because otherwise the fluid would phase separate like oil and water.”
The team synthesized the materials in their lab and tested their ability to absorb and release gases. They found that microporous water can reversibly transport extremely high densities of gases through water-based environments. Using this strategy, the team developed a porous liquid that can carry a higher density of O2 than is even present in the pure gas. These aqueous porous liquids display remarkable shelf-stability, allowing them to be stored at room temperature for months before use.
“With some more development, you could imagine storing oxygen in a microporous liquid on an ambulance to have it ready to inject into a person whenever its needed,” Wenny said.
The lab plans to conduct more experiments on microporous water to test its biomedical applications, while continuing to explore other potential uses for the materials.
“We want to develop more materials and animal models to create and test an oxygen carrier in vivo,” Erdosy said. “We also have a more energy-focused project planned on using microporous water to address gas transport challenges in electrocatalysis.”
This work was supported by grants from the Arnold and Mabel Beckman Foundation, the Department of Defense, the Department of Energy, and the Department of the Navy.
