Swimming Sea-Monkeys Reveal How Zooplankton May Help Drive Ocean Circulation

Brine shrimp, which are sold as pets known as Sea-Monkeys, are tiny—only about half an inch long each. With about 10 small leaf-like fins that flap about, they look as if they could hardly make waves.

But get billions of similarly tiny organisms together and they can move oceans.

It turns out that the collective swimming motion of Sea-Monkeys and other zooplankton—swimming plankton—can generate enough swirling flow to potentially influence the circulation of water in oceans, according to a new study by Caltech researchers.

The effect could be as strong as those due to the wind and tides, the main factors that are known to drive the up-and-down mixing of oceans, says John Dabiri, professor of aeronautics and bioengineering at Caltech. According to the new analysis by Dabiri and mechanical engineering graduate student Monica Wilhelmus, organisms like brine shrimp, despite their diminutive size, may play a significant role in stirring up nutrients, heat, and salt in the sea—major components of the ocean system.

In 2009, Dabiri's research team studied jellyfish to show that small animals can generate flow in the surrounding water. "Now," Dabiri says, "these new lab experiments show that similar effects can occur in organisms that are much smaller but also more numerous—and therefore potentially more impactful in regions of the ocean important for climate."

The researchers describe their findings in the journal Physics of Fluids.

Brine shrimp (specifically Artemia salina) can be found in toy stores, as part of kits that allow you to raise a colony at home. But in nature, they live in bodies of salty water, such as the Great Salt Lake in Utah. Their behavior is cued by light: at night, they swim toward the surface to munch on photosynthesizing algae while avoiding predators. During the day, they sink back into the dark depths of the water.

A. salina (a species of brine shrimp, commonly known as Sea-Monkeys) begin a vertical migration, stimulated by a vertical blue laser light.

To study this behavior in the laboratory, Dabiri and Wilhelmus use a combination of blue and green lasers to induce the shrimp to migrate upward inside a big tank of water. The green laser at the top of the tank provides a bright target for the shrimp to swim toward while a blue laser rising along the side of the tank lights up a path to guide them upward.

The tank water is filled with tiny, silver-coated hollow glass spheres 13 microns wide (about one-half of one-thousandth of an inch). By tracking the motion of those spheres with a high-speed camera and a red laser that is invisible to the organisms, the researchers can measure how the shrimp's swimming causes the surrounding water to swirl.

Although researchers had proposed the idea that swimming zooplankton can influence ocean circulation, the effect had never been directly observed, Dabiri says. Past studies could only analyze how individual organisms disturb the water surrounding them.

But thanks to this new laser-guided setup, Dabiri and Wilhelmus have been able to determine that the collective motion of the shrimp creates powerful swirls—stronger than would be produced by simply adding up the effects produced by individual organisms.

Adding up the effect of all of the zooplankton in the ocean—assuming they have a similar influence—could inject as much as a trillion watts of power into the oceans to drive global circulation, Dabiri says. In comparison, the winds and tides contribute a combined two trillion watts.

Using this new experimental setup will enable future studies to better untangle the complex relationships between swimming organisms and ocean currents, Dabiri says. "Coaxing Sea-Monkeys to swim when and where you want them to is even more difficult than it sounds," he adds. "But Monica was undeterred over the course of this project and found a creative solution to a very challenging problem."

The title of the Physics of Fluids paper is "Observations of large-scale fluid transport by laser-guided plankton aggregations." The research was supported by the U.S.-Israel Binational Science Foundation, the Office of Naval Research, and the National Science Foundation.

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Caltech's Green Revolving Fund: Financing Energy Efficiency

For the last six years, Caltech Facilities has managed a green revolving fund called the Caltech Energy Conservation Investment Program (CECIP) to finance energy efficiency projects around campus. To date the program has invested $18 million in such projects that can pay back their costs in less than six years. These investments have received $3 million in rebates and have returned more than $4.5 million to the loan fund in avoided utility costs. The program has been recognized with a number of awards, including, most recently, an Innovation Award from the National Association of College and University Business Officers (NACUBO).

"This award recognizes CECIP's unique combination of innovation in both facilities and finance," says Dean Currie, vice president for business and finance at Caltech. "CECIP is intensely rigorous in its measurement of actual building performance, both pre- and post-investment, and in its recalculation of savings based on actual energy prices, not just those that prevailed when the project was approved. The Caltech board was so impressed with the CECIP concept, that it authorized the continued investment of millions of dollars in the program right through the 2008-2009 financial crisis."

Launched in 2008, CECIP began as a concept for funding energy efficiency work on campus in a way that would not affect the operating budget. As a green revolving fund, the idea was to borrow an initial allocation from Caltech's endowment in order to finance projects that produce a return on investment of 15 percent or more. "The investments made in energy efficiency reduce campus-wide utility costs," says Matt Berbée, director of maintenance management and energy services at Caltech. "These utility reductions go back into the fund and can then be used to finance additional projects."

CECIP plays a key role in Caltech's Greenhouse Gas Mitigation Strategy. To date, Caltech has reduced direct emissions by more than 20 percent since 2008, putting the Institute well on its way to achieving its 2020 emissions reduction target.

The first CECIP-funded project was an LED lighting retrofit in the parking structures on Wilson Avenue. The project was completed in 2009 and has returned more in avoided utility costs than it cost to implement. Since that initial pilot, CECIP has funded dozens of projects across campus including full building automation controls and mechanical system upgrades in Broad Center, Moore Lab, and Beckman Institute.

Since CECIP's inception, Caltech's energy density—the Btu used per square foot of space—has dropped by about 10 percent. Another way to look at the impact of the CECIP projects is that, without them, the Institute would consume about 18 more gigawatt-hours of electricity every year (enough to power more than 1,600 homes).

"As energy efficiency projects are completed, the amount of energy supplied by the grid decreases, and this improves Caltech's carbon footprint," says Berbée. "This is not being green just to be green. These investments are about verified financial performance, reducing environmental impact, and keeping the focus on the main thing: efficiently operated and maintained space for research and education."

Currently, more than 30 CECIP projects are paying back into the fund, producing about half a million dollars every quarter in avoided utility costs.

Berbée says documenting and verifying those savings is necessary to CECIP's success. "We have the numbers to prove that this is working."

And those performance numbers have made CECIP a model for other organizations and institutions looking for ways to finance energy efficiency projects. On October 30, Caltech will host its fourth energy efficiency forum, where managers from other higher-education campuses, private research centers, real estate firms, and companies with campus-like facilities will come to learn about Caltech's efforts and to see CECIP projects firsthand.

"The energy efficiency forum is one of the ways we demonstrate our commitment to continuous improvement," says Berbée. "It allows for the exchange of best practices among industry leaders and offers us the ability to highlight the value of integrating energy management throughout all aspects of a building's life cycle."

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Checking the First Data from OCO-2

On July 2, NASA successfully launched its first satellite dedicated to measuring carbon dioxide in Earth's atmosphere. The Orbiting Carbon Observatory-2 (OCO-2) mission—operated by NASA's Jet Propulsion Laboratory—will soon provide atmospheric carbon dioxide measurements from thousands of points all over the planet. Last week, the satellite reached its proper orbit—meaning that it is now beginning to return its first data to Earth.

Data from the satellite will be used to help researchers understand the anthropogenic and natural sources of CO2, and how changing levels of the greenhouse gas may affect Earth's climate. But before OCO-2 provides scientists with such a global picture of the carbon cycle—where carbon is being produced and absorbed on Earth—researchers have to convert raw satellite data into a CO2 reading and then, just as importantly, make sure that the reading is accurate. A team of Caltech researchers is playing an instrumental role in this effort.

As it orbits, OCO-2 provides data about levels of atmospheric CO2 by measuring the sunlight that reflects off Earth, below. "OCO-2 measures something that is related to the CO2 measurement we want but it's not directly what we want. So from the reflected light, we have to extract the information about CO2," says Yuk Yung, the Smits Family Professor of Planetary Science.

The process begins with the satellite's instrument, a set of high-resolution spectrometers that measure the intensity of sunlight at different wavelengths, or colors, after it has passed twice through the atmosphere—once from the sun to the surface, and then back from the surface to space. As the satellite orbits, systematically slicing over sections of Earth's atmosphere, it will collect millions of these measurements.

"OCO-2 will provide the measurements of this light at different wavelengths in millions of what we call spectra, but spectra aren't what we really want—what we really want is to know how much carbon dioxide is in the atmosphere," Yung says. "But to get the CO2 information from the spectra, we have to do what's called data retrieval—and that's one of my jobs."

The data retrieval method that Yung and his colleagues designed for OCO-2 compares the light spectra collected by the satellite to a model of how light spectra would look—based on the laws of physics and knowledge of how efficiently CO2 absorbs sunlight. This knowledge, in turn, is derived from laboratory measurements made by Caltech professor of chemical physics Mitchio Okumura and his colleagues at JPL and the National Institute of Standards and Technology.

"To make scientifically meaningful measurements, OCO-2 has to detect CO2 with better than 0.3 percent precision, and that has meant going back to the lab and measuring the spectral properties with extraordinarily high precision," Okumura says. From this retrieval, the researchers determine the amount of CO2 in the atmosphere above each of OCO-2's sampling points.

However, when OCO-2 sends its first CO2 measurements back to Earth for analysis, they'll still have to go through one more check, says Paul Wennberg, the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering.

"Although the OCO-2 retrieval will calculate the amount of carbon dioxide above the point where the spectrometers pointed, we know that these initial numbers will be wrong until the data are calibrated," Wennberg says. Wennberg and his team provide this calibration with their Total Carbon Column Observing Network (TCCON), a ground-based network of instruments that measure atmospheric CO2 from approximately 20 locations around the world.

TCCON and OCO-2 provide the same type of CO2 measurement—what is called a column average of CO2. This measurement provides the average abundance of CO2 in a column from the ground all the way up through Earth's atmosphere.

About once per day, the OCO-2 instrument will be commanded to point at one of TCCON's stations continuously as it passes overhead. By comparing the Earth-based and space-based measurements, researchers will evaluate the data that they receive from the satellite and improve the retrieval method.

The complete, high-quality information OCO-2 provides about global CO2 levels will be important for researchers and policymakers to determine how human activity influences the carbon cycle—and how these activities contribute to our changing planet.

"A lot of the very first satellites were developed to study astronomy and planets far away. But there has been a shift. Our changing climate means that we now have a big need to study Earth," and the information OCO-2 provides about our atmosphere will be an important part of filling that need, says Yung.

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Corals Provide Clues for Climate Change Research

Just as growth rings can offer insight into climate changes occurring during the lifespan of a tree, corals have much to tell about changes in the ocean. At Caltech, climate scientists Jess F. Adkins and Nivedita Thiagarajan use manned submersibles, like Alvin operated by the Woods Hole Oceanographic Institution, to dive thousands of meters below the surface to collect these specimens—and to shed new light on the connection between variance in carbon dioxide (CO2) levels in the deep ocean and historical glacial cycles.

A paper describing the research appears in the July 3 issue of Nature.

It has long been known that ice sheets wax and wane as the concentration of CO2 decreases and increases in the atmosphere. Adkins and his team believe that the deep ocean—which stores 60 times more inorganic sources of carbon than is found in the atmosphere—must play a vital role in this variance.

To investigate this, the researchers analyzed the calcium carbonate skeletons of corals collected from deep in the North Atlantic Ocean. The corals were built up from 11,000–18,000 years ago out of CO2 dissolved in the ocean.

"We used a new technique that has been developed at Caltech, called clumped isotope thermometry, to determine what the temperature of the ocean was in the location where the coral grew," says Thiagarajan, the Dreyfus Postdoctoral Scholar in Geochemistry at Caltech and lead author of the paper. "We also used radiocarbon dating and uranium-series dating to estimate the deep-ocean ventilation rate during this time period." 

The researchers found that the deep ocean started warming before the start of a rapid climate change event about 14,600 years ago in which the last glacial period—or most recent time period when ice sheets covered a large portion of Earth—was in the final stages of transitioning to the current interglacial period.

"We found that a warm-water-under-cold-water scenario developed around 800 years before the largest signal of warming in the Greenland ice cores, called the 'Bølling–Allerød,'" explains Adkins. "CO2 had already been rising in the atmosphere by this time, but we see the deep-ocean reorganization brought on by the potential energy release to be the pivot point for the system to switch from a glacial state, where the deep ocean can hold onto CO2, and an interglacial state, where it lets out CO2."  

"Studying Earth's climate in the past helps us understand how different parts of the climate system interact with each other," says Thiagarajan. "Figuring out these underlying mechanisms will help us predict how climate will change in the future." 

Additional authors on the Nature paper, "Abrupt pre-Bølling–Allerød warming and circulation changes in the deep ocean," are geochemist John M. Eiler and graduate student Adam V. Subhas from Caltech, and John R. Southon from UC Irvine. 

Katie Neith
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DOE Awards $15 Million to Caltech's Solar Energy Research

The United States Department of Energy (DOE) announced on Wednesday that it will be awarding $15.2 million to Caltech's Light-Material Interactions in Energy Conversion (LMI) program, one of 32 Energy Frontier Research Centers (EFRCs) nationwide that will receive a combined $100 million over the next four years to pursue innovative energy research.

The LMI-EFRC is directed by Harry Atwater, the Howard Hughes Professor of Applied Physics and Materials Science, and is a collaborative partnership of researchers in photonics (the generation, manipulation, and detection of light) at Caltech, Lawrence Berkeley National Laboratory, the University of Illinois at Urbana-Champaign, Stanford University, and Harvard University.

The DOE received more than 200 proposals for EFRCs. Caltech is among 22 centers whose initial funding, granted in 2009, is being extended for another four years. During its first funding period, among other accomplishments, LMI-EFRC fabricated complex three-dimensional photonic nanostructure and light absorbers; created a solar cell with world-record-breaking efficiency; and developed the printing-based mechanical assembly of microscale solar cells.

"In recent years the solar energy landscape has been fundamentally altered with the recent growth of a large worldwide photovoltaics industry," says Atwater. "The most important area for basic research advances is now in enumerating the scientific principles and methods for achieving the highest conversion efficiencies. There is a new era emerging in which the science of nanoscale light management plays a critical role in enabling energy conversion to surpass traditional limits. This is where the Light-Material Interactions EFRC has focused its effort and is making advances."

LMI-EFRC will be using its new DOE award to address opportunities for high-efficiency solar energy conversion, with a goal of making scientific discoveries that will enable utilization of the entire visible and infrared solar resource.

"We are proud of the accomplishments of Professor Atwater, his colleagues, postdocs, and students in the Light-Material Interactions effort and are gratified that this effort will go beyond its great accomplishments to date through the renewed funding from the DOE," says Peter Schröder, deputy chair of the Division of Engineering and Applied Science and the Shaler Arthur Hanisch Professor of Computer Science and Applied and Computational Mathematics. "Harry exemplifies the best tradition of engineering at Caltech, creating the interface between fundamental science advances and their realization through engineering for the benefit of society at large."

According to the United States Department of Energy, "transforming the way we generate, supply, transmit, store, and use energy will be one of the defining challenges for America and the globe in the 21st century. At its heart, the challenge is a scientific one. Important as they are, incremental advances in current energy technologies will not be sufficient. History has demonstrated that radically new technologies arise from disruptive advances at the science frontiers. The Energy Frontier Research Centers program aims to accelerate such transformative discovery." 

Energy Secretary Ernest Moniz, in announcing the awards, said, "Today, we are mobilizing some of our most talented scientists to join forces and pursue the discoveries and breakthroughs that will lay the foundation for our nation's energy future."

Cynthia Eller
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Commencement Speaker Daniel Yergin Visits Caltech

This year's commencement speaker, Pulitzer Prize-winning energy expert Daniel Yergin, came to campus a day early to get better acquainted with Caltech's faculty and students, and in particular to learn more about Caltech's energy initiatives.

Yergin spent the morning touring JPL. "I was especially excited to see the Curiosity Rover," says Yergin. "Also, it was remarkable to actually be in the space flight operations center, having seen it in the news so often before."

In the afternoon at Caltech, Yergin specifically asked to spend most of his time meeting with people to learn more about their work. "Caltech is such a preeminent institution," says Yergin, "and I thought that coming for commencement provided a wonderful opportunity to get a sense of the culture here. Caltech has such a large impact for such a small place, and I wanted to experience more of it."

Of course, high on Yergin's agenda was the opportunity to meet with those engaged in research on sustainable energy. A mid-afternoon meeting at the Resnick Sustainability Institute yielded a lively exchange between Yergin, graduate students, and postdoctoral fellows about the future of energy research and the geopolitics of energy policy. Asked what he had learned from writing The Prize and The Quest, his two bestselling volumes on the history of oil, gas, and energy policy, Yergin replied that the main takeaway was that throughout the history of the industry, "everybody will feel they know where everything related to energy is going to go, and then in four or five years, something comes along to completely change it."

Stressing the increasingly important role of innovation in energy technology and geopolitics, especially as global markets continue to grow, Yergin says, "The challenge is that energy is a long-range investment and a long-range research project. It's very hard to say what is actually going to make a difference, but the cumulative impact of what you and people like you are doing is absolutely necessary. It's these kind of centers that will map the future of energy policy. The innovation is not going to come from big companies; it's going to come from universities and research institutes.  So keep doing what you're doing."

Cynthia Eller
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JCAP Stabilizes Common Semiconductors For Solar Fuels Generation

Caltech researchers devise a method to protect the materials in a solar-fuel generator

Researchers around the world are trying to develop solar-driven generators that can split water, yielding hydrogen gas that could be used as clean fuel. Such a device requires efficient light-absorbing materials that attract and hold sunlight to drive the chemical reactions involved in water splitting. Semiconductors like silicon and gallium arsenide are excellent light absorbers—as is clear from their widespread use in solar panels. However, these materials rust when submerged in the type of water solutions found in such systems.

Now Caltech researchers at the Joint Center for Artificial Photosynthesis (JCAP) have devised a method for protecting these common semiconductors from corrosion even as the materials continue to absorb light efficiently. The finding paves the way for the use of these materials in solar-fuel generators.

"For the better part of a half century, these materials have been considered off the table for this kind of use," says Nate Lewis, the George L. Argyros Professor and professor of chemistry at Caltech, and the principal investigator on the paper. "But we didn't give up on developing schemes by which we could protect them, and now these technologically important semiconductors are back on the table."

The research, led by Shu Hu, a postdoctoral scholar in chemistry at Caltech, appears in the May 30 issue of the journal Science.

In the type of integrated solar-fuel generator that JCAP is striving to produce, two half-reactions must take place—one involving the oxidation of water to produce oxygen gas; the other involving the reduction of water, yielding hydrogen gas. Each half-reaction requires both a light-absorbing material to serve as the photoelectrode and a catalyst to drive the chemistry. In addition, the two reactions must be physically separated by a barrier to avoid producing an explosive mixture of their products.

Historically, it has been particularly difficult to come up with a light-absorbing material that will robustly carry out the oxidation half-reaction. Researchers have tried, without much success, a variety of materials and numerous techniques for coating the common light-absorbing semiconductors. The problem has been that if the protective layer is too thin, the aqueous solution penetrates through and corrodes the semiconductor. If, on the other hand, the layer is too thick, it prevents corrosion but also blocks the semiconductor from absorbing light and keeps electrons from passing through to reach the catalyst that drives the reaction.

At Caltech, the researchers used a process called atomic layer deposition to form a layer of titanium dioxide (TiO2)—a material found in white paint and many toothpastes and sunscreens—on single crystals of silicon, gallium arsenide, or gallium phosphide. The key was that they used a form of TiO2 known as "leaky TiO2"—because it leaks electricity. First made in the 1990s as a material that might be useful for building computer chips, leaky oxides were rejected as undesirable because of their charge-leaking behavior. However, leaky TiO2 seems to be just what was needed for this solar-fuel generator application. Deposited as a film, ranging in thickness between 4 and 143 nanometers, the TiO2 remained optically transparent on the semiconductor crystals—allowing them to absorb light—and protected them from corrosion but allowed electrons to pass through with minimal resistance.

On top of the TiO2, the researchers deposited 100-nanometer-thick "islands" of an abundant, inexpensive nickel oxide material that successfully catalyzed the oxidation of water to form molecular oxygen.

The work appears to now make a slew of choices available as possible light-absorbing materials for the oxidation side of the water-splitting equation. However, the researchers emphasize, it is not yet known whether the protective coating would work as well if applied using an inexpensive, less-controlled application technique, such as painting or spraying the TiO2 onto a semiconductor. Also, thus far, the Caltech team has only tested the coated semiconductors for a few hundred hours of continuous illumination.

"This is already a record in terms of both efficiency and stability for this field, but we don't yet know whether the system fails over the long term and are trying to ensure that we make something that will last for years over large areas, as opposed to weeks," says Lewis. "That's the next step."

The work, titled "Amorphous TiO2 Coatings Stabilize Si, GaAs, and GaP Photoanodes for Efficient Water Oxidation," was supported by the Office of Science of the U.S. Department of Energy through an award to JCAP, a DOE Energy Innovation Hub. Some of the work was also supported by the Resnick Sustainability Institute and the Beckman Institute at Caltech. Additional coauthors on the paper are graduate students Matthew Shaner, Joseph Beardslee, and Michael Lichterman, as well as Bruce S. Brunschwig, director of the Molecular Materials Resource Center at Caltech.

Kimm Fesenmaier
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Stabilizing Semiconductors for Solar Fuels Generation
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Resonate Awards Honor Global Champions of Sustainability

New awards granted by the Resnick Sustainability Institute recognize emerging global innovators in energy science and environmental policy.

On May 19, the Resnick Sustainability Institute at Caltech announced five innovators in the fields of energy science and sustainability as the inaugural winners of the Resonate Awards.

As part of the Resnick Sustainability Institute's mission to advance research in renewable energy and sustainability science, the new award is meant to draw attention to important work in green innovation, which is often overlooked among other advances in technology. The Resonate Award recognizes early career researchers and emerging leaders in sustainability who have the potential to make a significant global impact but have not yet received widespread recognition.

With the award, the Resnick Sustainability Institute will honor those who have contributed to green solutions in a variety of fields including science, technology, economics, and public policy.

"We are committed to finding scalable long-term solutions to some of the biggest energy and environmental problems facing the world today," says Harry Atwater, the Howard Hughes Professor of Applied Physics and Materials Science and director of the Resnick Sustainability Institute. "We started the Resonate Awards because we realized that there is an urgent need to recognize and promote the advances of sustainability innovators."

After receiving more than 50 candidate nominations last fall, an internal review panel narrowed the field to 12 finalists, from which the five 2014 Resonate Award winners were selected by a panel of judges from industry, academia, international governments, and journalism:

  • Thomas Francisco Jaramillo, an assistant professor in the Department of Chemical Engineering at Stanford University, received the Resonate Award "for catalyzing chemical reactions for renewable energy production and storage." Jaramillo's work has led to the discovery of stable earth-abundant catalysts that drive chemical reactions for renewable hydrogen production from water and the sustainable conversion of carbon dioxide into fuels and chemicals.
  • Sarah Kearney, the founder and executive director of PRIME Coalition, was honored "for designing flexible impact-focused investment models to fund innovative ventures offering scalable solutions to global social problems." At PRIME Coalition, a membership-based nonprofit, Kearney's work links philanthropists and investors to high-risk, high-reward startups addressing global environmental and social problems.
  • Shinichi Komaba, a professor of applied chemistry at Tokyo University of Science and project professor at Kyoto University, was selected "for developing materials for safe, efficient battery storage for electric vehicles and the grid." Komaba's research in the field of energy storage is aimed at making batteries safer and more efficient—an important step in the design of zero-emission vehicles.
  • Javad Lavaei (PhD '11), an assistant professor in the Department of Electrical Engineering at Columbia University, was chosen "for building a computational backbone to transform the power grid into one that is flexible, smart and dynamic." Lavaei's interdisciplinary work in math, control and optimization theory, economics, and computer science provides a computational framework for incorporating renewable energy into the electricity grid in an efficient and cost-effective manner.
  • Jay Whitacre, an associate professor at Carnegie Mellon University and founder and chief technology officer of Aquion Energy was awarded "for research and development of scalable, environmentally benign, low-cost grid-scale energy storage." Whitacre's contributions to finding safe, reliable, cost-effective, and sustainable energy storage solutions resulted in the development of a sodium-based electrolyte battery technology that can be made with low-cost materials.

"Each of these extraordinary sustainability champions has combined academic and professional excellence with imagination and boldness to not only envision but create solutions to the pressing challenges that face us today and tomorrow," Atwater says.

The awards will be presented at the Fortune magazine Brainstorm GREEN conference this week in Laguna Niguel, California. In addition to receiving their honors, the awardees will also give presentations at the conference.

For more information about the awards, please see the Resonate Awards webpage.

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Awards Honor Global Champions of Sustainability
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New Gift Helps Caltech Address Global Challenges in Clean Energy and Sustainability

A new $15 million gift by Lynda and Stewart Resnick in support of the Resnick Sustainability Institute at Caltech will help scientists and engineers advance research aimed at helping humanity sustainably meet its needs for energy, food, clean water, and a healthy environment. This brings total funding of the Resnick Sustainability Institute to nearly $60 million, beginning with a foundational $21 million gift from the Resnicks in 2009.

Since its founding, the Resnick Sustainability Institute's researchers have pursued wide-ranging investigations in energy science and technology. Support from the Resnick Sustainability Institute has enabled advances in distributed wind-energy systems, batteries and fuel cells, smart grid systems, record-breaking solar photovoltaics, pioneering technologies for deriving fuels from sunlight, and chemical catalysts that convert waste materials to biofuels.

"Securing a sustainable source of energy for future generations is the most fundamental issue facing mankind," says Stewart Resnick, Caltech senior trustee and the chairman and co-owner, along with his wife, Lynda, of Roll Global, a private holding company with interests in fresh fruit and tree nuts, premium beverages, and floral delivery. "It is at the heart of all of the other long-term sustainability challenges such as feeding the world's population and providing people with access to clean water and health care. We see funding Caltech's efforts as an investment in our future, not just as philanthropy." Caltech, he adds, is uniquely qualified to address the problems that challenge our world: "The intimacy of its campus allows many diverse scientific disciplines to easily and regularly come together for a kind of innovative thinking that is hard to achieve elsewhere."

Inspired by the success of the first generation of research at the Resnick Sustainability Institute, $3 million of the Resnicks' new gift establishes the Resnick Institute Innovation Fund, which will support new ideas in clean-energy and sustainability science that have the potential for rapid impact. The fund will initially focus on two programs. The first is the Resnick Sustainability Institute's newly launched Resonate Awards program, which will honor creative breakthroughs in energy and sustainability science made by early-career scholars worldwide. The second, a postdoctoral scholar program offering distinguished fellowships, will help bring particularly outstanding young leaders in energy and sustainability research to Caltech to create a corps of top innovators who will have the freedom to focus exclusively on research.

In keeping with the Resnick Sustainability Institute's innovative programming, a major portion of the gift—$12 million—establishes the Lynda and Stewart Resnick Matching Program. This program will provide a one-to-one match for contributions that create new, endowed funds within the Resnick Sustainability Institute, and thus will represent a potential $24 million in long-term funding. Through the Resnick match, a new donation that would have supported one graduate or postdoctoral fellowship, for example, will now provide for two. Because each endowed fund will be managed to work in perpetuity, each will support energy and sustainability research, education, and outreach over decades.

"The toughest issues in sustainability are not short-term, two- or three-year problems," says Harry A. Atwater, Howard Hughes Professor of Applied Physics and Materials Science and director of the Resnick Sustainability Institute. "They require a 50-year view and need to be approached with creativity and a transformative perspective. Lynda and Stewart Resnick's generosity and vision are critical to the future."

"The Resnick Sustainability Institute has helped to transform the landscape for energy research and education at Caltech," says Edward Stolper, interim president, and provost. "Creating a central hub to connect all our faculty who work on energy has accelerated the pace of discovery." Stolper continues, "We are grateful to Stewart and Lynda for their longstanding and generous support of Caltech. The Resnicks' new gift continues their tradition of strong support for faculty research and provides for new outreach programs so that the results of energy research can be shared with audiences worldwide."

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On the Front Lines of Sustainability

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On the Front Lines of Sustainability

The chemical processes used to make products ranging from pharmaceuticals to perfumes can have a harmful impact on the environment. However, Caltech chemist and Nobel laureate Robert Grubbs has spent several decades developing catalysts—compounds that speed up a chemical reaction—that can make the synthesis of these products more efficient and ecologically friendly, ultimately reducing their environmental footprint. Similarly, chemist Brian Stoltz is developing new strategies for the synthesis of compounds needed in the chemical, polymer, and pharmaceutical industries. His new processes rely upon oxygen and organometallic catalysts—greener alternatives to the toxic metals that are normally used to drive such reactions.

Switching from paper files to cloud-based data storage might seem like an obvious choice for sustainability, but can we further reduce the environmental impact of storing data? The theoretical work of engineer and computer scientist Adam Wierman suggests that with the right algorithms, we can. Today, data centers—the physical storage facilities Wierman calls the "SUVs of the Internet"—account for more than 1.5 percent of U.S. electricity usage. And as more data goes online, that number is expected to grow. Wierman's work helps engineers design algorithms that will reroute data, with preference to centers that use renewable energy sources like wind and solar.

Energy from the sun—although free and abundant—cannot easily be stored for use on dreary days or transported to cloudy regions. Caltech engineer and materials scientist Sossina Haile hopes to remove that barrier with a specific type of solar reactor she has developed. The reactor is lined with ceramic cerium oxide; when this lining is heated with concentrated sunlight it releases oxygen, priming it to remove oxygen from water molecules or carbon dioxide on cooling, thus creating hydrogen fuel or "syngas"—a precursor to liquid hydrocarbon fuels. This conversion of the sun's light into storable fuel could allow solar-derived power to be available day and night.

Caltech student participants in the Department of Energy's biennial Solar Decathlon competition set out to prove that keeping a house lit up, cooled down, and comfortable for living is possible—even while off the grid. The Techers teamed up with students at the Southern California Institute of Architecture to create CHIP and DALE, their entries in the 2011 and 2013 competitions, respectively. These functional and stylish homes, powered solely by the sun, were engineered with innovative components including a rainwater collection system and moving room modules that optimize heating and cooling efficiency. 

Although many of us take the nearest bathroom for granted, working toilets require resources and infrastructure that may not be available in many parts of the world. Inspired by the "Reinventing the Toilet Challenge" issued by the Bill and Melinda Gates Foundation, environmental scientist and engineer Michael Hoffmann and his team applied his research in hydrogen evolution and water treatment to reengineer the toilet. The Caltech team's design—which won the challenge in 2012—can serve hundreds of people each day, treat its own wastewater, and generate electricity, providing a sustainable and low-cost solution to sanitation and hygiene challenges in the developing world. Prototypes are being tested in India and China for use in urban and remote environments in the developing world.  

Geophysicist Mark Simons studies the mechanics of the Earth—furthering our understanding of what causes our planet to deform over time. His research often involves using satellite data to observe the movement associated with seismic and volcanic activity, but Simons is also interested in changes going on in the icy parts of Earth's surface, especially the dynamics of glaciers. By flying high above Iceland's ice caps, Simons and his colleagues can track the glaciers' melt-and-freeze response in relation to seasonal and long-term variations in temperature—and their potential response to climate change.

The production of industrial nitrogen fertilizer results in 130 million tons of ammonia annually—while also requiring high heat, high pressure, and lots of energy. However, in a process called nitrogen fixation, soil microorganisms that live near the roots of certain plants can produce a similar amount of ammonia each year. The bugs use catalysts called nitrogenases to convert nitrogen from the air into ammonia at room temperature and atmospheric pressure. By mimicking the behavior of these microorganisms, Jonas Peters and his colleagues synthesized an iron-based catalyst that allows for nitrogen fixation under much milder conditions. The catalyst could one day lead to more environmentally friendly methods of ammonia production.

Traditionally, the photovoltaic cells in solar panels have been expensive and have had limited efficiency—making them a hard sell in the consumer market. Engineer and applied physicist Harry Atwater's work suggests that there is a thinner and more efficient alternative. Atwater, who is also the director of the Resnick Sustainability Institute, uses thin layers of semiconductors to create photovoltaics that absorb sunlight as efficiently as thick solar cells but can be produced with higher efficiency than conventional cells.

The generation of chemical fuels from sunlight could completely change the way we power the planet. Researchers in the laboratory of Caltech chemist Nate Lewis are working to develop different components of a fuel-producing device that could do just that called a photoelectrochemical cell. The cell would consist of an upper layer that could absorb sunlight, carbon dioxide, and water vapor, a middle layer consisting of light absorbers and catalysts that can produce fuels, which are then released through the device's bottom layer. When such a device is created, the Joint Center for Artificial Photosynthesis, of which Lewis is the scientific director, aims to ease the transfer of these technologies to the private sector. 

Clean energy from the wind is a promising alternative to fossil fuels, but giant pinwheel-like wind turbines that are common on many wind farms can create dangerous obstacles for birds as well as being an unpleasant addition to a landscape's aesthetic. To combat this problem, Caltech engineer and fluid-mechanics expert John Dabiri is testing a new design for wind turbines, which looks a bit like a spinning eggbeater emerging from the ground. By placing these columnar vertical wind turbines in a careful arrangement—an arrangement inspired by the vortex of water created behind a swimming fish—his smaller vertical turbines create just as much energy as the "pinwheels" and on a much smaller land footprint.

In the early 1990s, Caltech bioengineer Frances Arnold pioneered "directed evolution"—a new method of engineering custom-built enzymes, or activity-boosting proteins. The technique allows mutations to develop in the enzyme's genetic code; these mutations can give the enzyme properties that don't occur in nature but are beneficial for human applications. The selectively enhanced enzymes help microbes turn plant waste and fast-growing grasses into fuels like isobutanol, which could sustainably replace more than half of U.S. oil imports, Arnold says. She's also exploring ways the technique could help factories to make pharmaceuticals and other products in much cleaner and safer ways.

The combined research efforts of Richard Flagan, John Seinfeld, Mitchio Okumura, and Paul Wennberg aim to improve our understanding of various aspects of climate change. Chemical engineer Flagan is pioneering ways to measure the number and sizes of particles in the air down to that of large molecules. Seinfeld studies where particles in the air come from, how they are produced by airborne chemical reactions, and the effect they have on the world's climate. Chemical physicist Okumura studies the chemical reactions that occur when sunlight encounters air pollution and results in smog. Wennberg, an atmospheric chemist, studies the natural and human processes that affect smog formation, the health of the ozone layer, as well as the lifetime of greenhouse gases. Wennberg and his colleagues join a legacy of Caltech researchers who have improved air quality through key discoveries about pollution.

In the past, researchers have discovered materials that can act as reaction catalysts, driving sunlight to split water into hydrogen fuel and an oxygen byproduct. However, these wonder materials are often expensive and in short supply. The research of chemist Harry Gray, who leads the National Science Foundation-funded Center for Chemical Innovation in Solar Fuels program, tests combinations of Earth-abundant metals to search for an inexpensive catalyst that boosts the water-splitting reaction with the sun. Gray also coleads an outreach project in which students in the classroom can participate in the race for solar fuels by testing thousands of materials and reporting their results to Caltech researchers.


Although Earth Week has officially come to a close, Caltech's commitment to sustainability continues. In this feature, you will meet some of the researchers at Caltech whose work is contributing to a greener planet and to the long-term improvement of our global environment.