Darlene Bushue/FlickrRead More
More old-growth forests have been lost than the biosphere can bear. New peer-reviewed ecological science by Dr. Glen Barry indicates that some 66% of Earth’s land must be covered by natural and semi-natural ecosystems to avoid biosphere collapse, yet some 50% has already been lost. Nowhere has the damage been worse than Europe which sadly continues to log its last naturally evolved wildlands, seriously harming local ecosystems and continental scale potential for ecological sustainability. Vast tracts of forest in the Carpathian mountain range are home to Europe`s largest populations of brown bears, wolves and lynx – all long absent from most of Europe — as well as other large mammals like bison (Bison bonasus). They are being corruptly preyed upon by Austria’s Holzindustrie Schweighofer for cheap consumer items. Please take affinity action with EcoInternet to protect some of Europe’s last large connected old-growth forests in Romania. Demand that all old-growth logging end and these forests be protected and allowed to expand.Read More
The year 2015 proved to be another groundbreaking year for research at Caltech. From seeing quantum motion, to reconfiguring jellyfish limbs, to measuring stellar magnetic fields, researchers continued to ask and answer the deepest scientific questions.
In case you missed any of them, here are 15 stories highlighting a few of the discoveries, methods, and technologies that came to life at Caltech in 2015.
Deep inside the earth, seismic observations reveal that three distinct structures make up the boundary between the earth’s metallic core and overlying silicate mantle at a depth of about 2,900 kilometers—an area whose composition is key to understanding the evolution and dynamics of our planet. These structures include remnants of subducted plates that originated near the earth’s surface, ultralow-velocity zones believed to be enriched in iron, and large dense provinces of unknown composition and mineralogy. A team led by Caltech’s Jennifer Jackson, professor of mineral physics has new evidence for the origin of these features that occur at the core-mantle boundary.
“We have discovered that bridgmanite, the most abundant mineral on our planet, is a reasonable candidate for the material that makes up these dense provinces that occupy about 20 percent of the core-mantle boundary surface, and rise up to a depth of about 1,500 kilometers. Integrated by volume that’s about the size of our moon!” says Jackson, coauthor of a study that outlines these findings and appears online in the Journal of Geophysical Research: Solid Earth. “This finding represents a breakthrough because although bridgmanite is the earth’s most abundant mineral, we only recently have had the ability to precisely measure samples of it in an environment similar to what we think the materials are experiencing inside the earth.”
Previously, says Jackson, it was not clear whether bridgmanite, a perovskite structured form of (Mg,Fe)SiO3, could explain seismic observations and geodynamic modeling efforts of these large dense provinces. She and her team show that indeed they do, but these structures need to be propped up by external forces, such as the pinching action provided by cold and dense subducted slabs at the base of the mantle.
Jackson, along with then Caltech graduate student Aaron Wolf (PhD ’13), now a research scientist at the University of Michigan at Ann Arbor, and researchers from Argonne National Laboratory, came to these conclusions by taking precise X-ray measurements of synthetic bridgmanite samples compressed by diamond anvil cells to over 1 million times the earth’s atmospheric pressure and heated to thousands of degrees Celsius.
The measurements were done utilizing two different beamlines at the Advanced Photon Source of Argonne National Laboratory in Illinois, where the team used powerful X-rays to measure the state of bridgmanite under the physical conditions of the earth’s lower mantle to learn more about its stiffness and density under such conditions. The density controls the buoyancy—whether or not these bridgmanite provinces will lie flat on the core-mantle boundary or rise up. This information allowed the researchers to compare the results to seismic observations of the core-mantle boundary region.
“With these new measurements of bridgmanite at deep-mantle conditions, we show that these provinces are very likely to be dense and iron-rich, helping them to remain stable over geologic time,” says Wolf.
Using a technique known as synchrotron Mössbauer spectroscopy, the team also measured the behavior of iron in the crystal structure of bridgmanite, and found that iron-bearing bridgmanite remained stable at extreme temperatures (more than 2,000 degrees Celsius) and pressure (up to 130 gigapascals). There had been some reports that iron-bearing bridgmanite breaks down under extreme conditions, but the team found no evidence for any breakdown or reactions.
“This is the first study to combine high-accuracy density and stiffness measurements with Mössbauer spectroscopy, allowing us to pinpoint iron’s behavior within bridgmanite,” says Wolf. “Our results also show that these provinces cannot possibly contain a large complement of radiogenic elements, placing strong constraints on their origin. If present, these radiogenic elements would have rapidly heated and destabilized the piles, contradicting many previous simulations that indicate that they are likely hundreds of millions of years old.”
In addition, the experiments suggest that the rest of the lower mantle is not 100 percent bridgmanite as had been previously suggested. “We’ve shown that other phases, or minerals, must be present in the mantle to satisfy average geophysical observations,” says Jackson. “Until we made these measurements, the thermal properties were not known with enough precision and accuracy to uniquely constrain the mineralogy.”
“There is still a lot of work to be done, such as identifying the dynamics of subducting slabs, which we believe plays a role in providing an external force to shape these large bridgmanite provinces,” she says. “We know that the earth did not start out this way. The provinces had to evolve within the global system, and we think these findings may help large-scale geodynamic modeling that involves tectonic plate reconstructions.”
The results of the study were published in a paper titled “The thermal equation of state of (Mg,Fe)SiO3bridgmanite (perovskite) and implications for lower mantle structures.” In addition to Jackson and Wolf, other authors on the study are Przemeslaw Dera and Vitali B. Prakapenka from the Center for Advanced Radiation Sources at Argonne National Laboratory. Support for this research was provided by the National Science Foundation, the Turner Postdoctoral Fellowship at the University of Michigan, and the California Institute of Technology.
Plants are an important mediator between the earth and the atmosphere. In order to grow, they breathe in carbon dioxide—one of the major greenhouse gases. Caltech associate professor Christian Frankenberg is interested in this relationship and how the biosphere reacts to climate change.
A native of Germany, Frankenberg earned a Diploma degree at the University of Bayreuth and a PhD at Ruprecht-Karls-University in Heidelberg. He spent the past five years as a research scientist at JPL and joined the Caltech faculty this fall. We recently spoke with Frankenberg about remote sensing, the biosphere, and life in Pasadena.
What do you do?
I use remote sensing tools—based on spectrometers in space and the air—to gain a deeper understanding of the carbon cycle. This means making measurements of atmospheric greenhouse gases like carbon dioxide and methane as well as measuring plant activity by sensing solar-induced chlorophyll fluorescence from space. Chlorophyll fluorescence happens when plants take in sunlight. A tiny fraction of that sunlight gets emitted at a slightly longer wavelength. We can see this glow from space, and it is a good proxy of the photosynthetic uptake of CO2 by plants.
One of my goals is to combine the atmospheric measurements and the fluorescence measurements to gain a deeper understanding of when, where, and why the carbon cycle changes. I work with the Orbiting Carbon Observatory 2 (OCO-2) at JPL, and also with a Japanese project called the Greenhouse Gases Observing Satellite (GOSAT).
Why is it important to understand the carbon cycle?
Many people are familiar with the famous Keeling Curve—a ground-based measurement of atmospheric carbon dioxide that has been ongoing since 1958. This curve shows a continual increase in CO2 abundances from year to year, but it also shows a strong seasonal cycle—abundances go up in winter and down in summer. This is because in the Northern Hemisphere summer, plants are growing and removing CO2 from the atmosphere; in winter, plants are releasing CO2.
If we count all the barrels of oil and everything else that we burn to release CO2, only about one-half of it remains in the atmosphere. One-fourth goes into the oceans, and the rest is taken up by vegetation. The biosphere is doing us a big favor in taking up a lot of what we’re emitting, but we don’t know exactly where on Earth that vegetation is absorbing the most or if will it persist in the future.
What can we do to improve our relationship with the biosphere?
There’s always talk about reducing CO2 emissions, which is great, but often actions are pound-foolish and penny-wise. I think energy efficiency is a big factor in improving our relationship with the biosphere. This means probably not having single-pane windows, and it definitely means not running the air conditioning and the heater at the same time, which I’ve seen (too often)! I do see a great opportunity for clean solar power in California—there’s so much sun!
How did you get interested in biogeosciences?
At school I liked natural sciences, like math and chemistry, but I didn’t want to focus on just one of them. During my undergraduate education, I studied geoecology, which gives a broad background of all the natural sciences. But I found out pretty quickly that I liked the more quantitative stuff, so I focused on the physics, math, and chemistry aspects, and did my PhD in environmental physics. That’s where I started working on remote sensing. I really liked it; the combination of working with the biosphere but also doing more technical work suited me. Now it seems I’m making a full turn again with my plant-based research. It’s like going back to my geoecology roots.
What brought you to Caltech?
I’ve always been interested in Caltech, but after a postdoc in the Netherlands, I got a job offer from JPL—five and a half years ago. I knew that in the long term, I wanted to be in academia doing more basic research and having academic freedom.
How does your job as a professor differ from your previous appointment as a research scientist?
I still retain the title of research scientist at JPL, and I spend one day a week there. For me, it’s an ideal situation to be at Caltech but still have the relationship with JPL, where so many things are happening in my field.
But now that I am on the Caltech faculty, I’ll be expanding from pure remote sensing to ground-based and laboratory measurements of fluorescence and carbon exchange. We are studying the part of plants that are more relevant for the global carbon cycle, connecting the leaf scale to the global scale. Additionally, I will start teaching courses in the next academic year, which will probably be the biggest change.
What do you like about being in Southern California?
I like the mountains a lot. Pasadena is a nice combination of having a small-town feeling next to the foothills but also having a big city nearby if you want it. It’s a sweet spot. What I miss most from Europe is the ability to just bike everywhere you need to go. There is no way to get around without a car here in the L.A. area.
What do you do outside of work?
I try to let the weekend be a weekend and not let it be too busy. I like getting outdoors, hiking and running, playing some soccer or squash. And, of course, spending time with my family and son is also a full-time sort of job.
Dear Earth loving friends,
My work and I have been here for the global environment, rock solid, for over 25 years. And now I urgently request your assistance to together continue our wildly successful deep ecology work.
For Earth, please donate what you can now at: http://www.climateark.org/shared/donate/
EcoInternet is one of the oldest and most successful online environmental campaign efforts ever. We are mid-way through a major revamping of our efforts and need your financial support right away.
Unfortunately, within coming weeks, EcoInternet faces a short-term cash crunch whereby we may be unable to afford to keep our servers online. We appeal to you to make your secure tax-deductible gift to EcoInternet right away!
EcoInternet and I are internationally recognized experts in the use of networked databases to facilitate environmental conservation. For decades we have innovated online methods – which some have called visionary – to communicate the severity of ecological decline while proposing specific policy solutions sufficient to achieve global ecological sustainability.
Over the past year EcoInternet contributed to several major environmental victories including helping protect (for now) ancient cave art and rainforests in Papua New Guinea. We have also revamped and accelerated our deep ecology essays, and are far along in research and development of a big data based ecological search engine.
Most visibly, EcoInternet continues to provide a valuable service on our web sites and social media to the global community – aggregating and archiving environmental news coverage, currently of the Paris climate talks. No one follows climate, forests, and the environment with dynamic and thoughtful deep ecology micro-blogging like EcoInternet at http://www.twitter.com/EcoInternet and http://www.facebook.com/EcoInternet
I have also been putting some of my energy into educating about fascism, on the rise as an authoritarian response to ecological decline.
Please support EcoInternet if you feel we must remain both free and green as we come together to sustain being.
Dr. Glen BarryRead More