Scientists have yet to find evidence of life on Mars, but a new study from researchers at NASA’s Jet Propulsion Laboratory, the 91̽�� and other universities suggests microbes could find a potential home beneath  layers of ice known to exist on Mars’ surface.

In the , published Oct. 17 in Communications Earth & Environment, authors showed that enough sunlight shines through surface ice for photosynthesis to occur in shallow subsurface pools of meltwater. Similar subsurface meltwater pools that form within ice on Earth have been found to teem with life, including algae, fungi, and microscopic cyanobacteria, all of which derive energy from the sun via photosynthesis.

“If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking,” said lead author at NASA’s Jet Propulsion Laboratory, who will join the 91̽��Applied Physics Laboratory as a senior research scientist in November.

Unlike Earth, Mars has two kinds of ice: frozen water and frozen carbon dioxide. The new study focused on water ice, largely formed from snow mixed with dust that fell during a series of Martian ice ages during the past million years. That ancient snow has since solidified into ice, still peppered with specks of dust.

Those dust particles are key to explaining how subsurface pools of water would form within ice when exposed to solar rays: dark dust absorbs more sunlight than the surrounding ice, causing the deeper ice to warm up and melt up to a few feet below the surface.

It’s a matter of debate whether ice can actually melt and exist as a liquid on the surface of Mars due to the planet’s thin, dry atmosphere, where water ice is believed to sublimate – turn directly into gas – the way dry ice does on Earth. But the atmospheric effects that make melting difficult on the surface wouldn’t apply below the surface of a dusty snowpack or glacier.

This new paper uses computer modeling to suggest that dusty ice lets in enough light for photosynthesis to occur as deep as 10 feet (3 meters) below the surface. In this scenario, the upper layers of ice prevent the shallow subsurface pools of water from evaporating while also providing protection from harmful radiation. That’s important given that, unlike Earth, Mars lacks a protective magnetic field to shield it from both the sun’s ultraviolet rays and radioactive cosmic ray particles zipping around space.

The water ice that would be most likely to form these subsurface pools would exist in Mars’ midlatitudes — between the latitudes of 30 degrees and 60 degrees — in both the northern and southern hemispheres.

“This latest paper examines the propagation of solar radiation into the ice, showing that just below the surface there is a zone that is safe from ultraviolet but still gets enough visible light to support photosynthesis,” said co-author , professor emeritus of Earth and space sciences at the UW. “But of course photosynthetic organisms won’t survive unless the ice in that zone can melt, at least occasionally.”

At the UW, Khuller plans to continue working to determine where liquid water is likely to exist on Mars. The next step, Khuller said, will be to recreate some of Mars’ dusty ice in a lab setting. Meanwhile, he and others are beginning to map out the most likely spots on Mars to look for shallow meltwater — scientific targets for possible human and robotic missions in the future.

at the University of Colorado Boulder is also a co-author on the new paper.

For more information, contact Khuller at akhuller@uw.edu and Warren at sgw@uw.edu.

Adapted from a NASA Jet Propulsion Laboratory .

Research led by the 91̽�� proposes a new idea that may explain why some Antarctic icebergs are tinged emerald green rather than the normal blue, potentially solving a decades-long scientific mystery.

The is published in the Journal of Geophysical Research: Oceans, a journal of the American Geophysical Union.

Pure ice is blue because ice absorbs more red light than blue light. Most icebergs appear white or blue when floating in seawater, but since the early 1900s, explorers and sailors have reported seeing peculiar green icebergs around certain parts of Antarctica.

These green icebergs have been a curiosity to scientists for decades, but now glaciologists suspect iron oxides in rock dust from Antarctica’s mainland are turning some icebergs green. They formulated the new theory after Australian researchers discovered in East Antarctica’s Amery Ice Shelf.

Iron is a key nutrient for phytoplankton, microscopic plants that form the base of the marine food web. But iron is scarce in many areas of the ocean.

If experiments prove the new theory right, it would mean green icebergs are ferrying precious iron from Antarctica’s mainland to the open sea when they break off, providing this key nutrient to the organisms that support nearly all marine life.

“It’s like taking a package to the post office. The iceberg can deliver this iron out into the ocean far away, and then melt and deliver it to the phytoplankton that can use it as a nutrient,” said lead author , a glaciologist and professor emeritus in the UW’s Department of Atmospheric Sciences.  “We always thought green icebergs were just an exotic curiosity, but now we think they may actually be important.”

Warren started studying the phenomenon on an Australian expedition in 1988, when he took a core sample from a green iceberg near the Amery Ice Shelf on the coast of East Antarctica.

Interestingly, the green ice he saw was a deep emerald hue, much darker and clearer than that of normal icebergs — a signal to scientists that green ice might be different from regular iceberg ice.

“When we climbed up on that iceberg, the most amazing thing was actually not the color, but rather the clarity,” Warren said. “This ice had no bubbles. It was obvious that it was not ordinary glacier ice.”

Icebergs break off of glaciers and ice shelves that jut out into the sea. Typical glacier ice forms when layers of snow build up and solidify over time, so it naturally has air pockets that reflect light.

But in Antarctica, some icebergs have a layer of what’s called marine ice: ocean water frozen to the underside of an overhanging ice shelf. Marine ice is clearer and darker than glacier ice because it doesn’t have any air pockets to reflect light.

When Warren and his colleagues analyzed that iceberg and other green icebergs sampled by Australian expeditions in the 1980s, they found the green parts were made of marine ice and not glacier ice. They suspected an impurity in the ocean water underneath the Amery Ice Shelf was turning some marine ice green.

Their first thought was that dissolved organic carbon, microscopic particles of long-dead marine plants and animals, was getting trapped in the ice as the water froze to the underside of the ice shelf. Dissolved organic carbon is yellow, so if pure ice is blue, the addition of yellow particles could turn the ice green, according to Warren.

But when Warren and his colleagues sampled icebergs on a subsequent expedition in 1996, they found green marine ice had the same amount of organic material as blue marine ice, so something else had to be responsible for the green color.

The problem nagged at Warren until a few years ago, when an oceanographer at the University of Tasmania tested an ice core from the Amery Ice Shelf for its iron content. She found marine ice near the bottom of the core had more iron than the glacial ice above.

Iron oxides found in soil, rocks, and common rust tend to have warm, earthy hues — yellows, oranges, reds and browns. So Warren began to suspect iron oxides in the marine ice could turning blue ice green. But where was the iron coming from?

As glaciers flow over bedrock, they grind rocks to a fine powder known as . When the ice meets the sea, this glacial flour flows into the ocean. If the rock dust becomes trapped under an ice shelf, the particles could be incorporated in marine ice as it forms.

Warren now suspects iron oxides in glacial flour from rocks on Antarctica’s mainland are responsible for creating the stunning emerald icebergs. He and the Australian iron researchers now propose to sample icebergs of different colors for their iron content and light-reflecting properties. If their theory proves correct, green icebergs could be more important than scientists thought.

Co-authors on the study are at the UW; at Bowdoin College; and at the Australian Antarctic Division. The research was supported by the Australian Antarctic Division and the U.S. National Science Foundation.

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For more information, contact Warren at sgw@uw.edu or 206-543-7230.

This release was by the American Geophysical Union.

Grants: OPP‐95‐27244 and OPP‐95‐27245

Recent notable books by 91̽�� authors tell of the struggle to break free of racism in higher education, taking an “urban diary” approach to documenting city life and more.

Stifling academic expression on campus in the 1960s and beyond

has been interested in the Black Power movement since she wrote her dissertation at the University of Illinois. Over time, as she examined how that activism played out in the South in the 1960s, she saw how colleges and universities stifled student expression and faculty academic freedom. Williamson-Lott, a professor in the 91̽��College of Education, has turned her research on that era into a book, “,” published in June by Teachers College Press.

Fifty years later, she says, those battles, and the racism underlying them, remain relevant in all parts of the country. “There’s something to be learned from the Southern experience,” Williamson-Lott says. “In a way, it wasn’t exceptional. It’s who we are as a nation.”

To learn more, contact Williamson-Lott at joyann@uw.edu.

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Studying the use of secrets in world cinema

How are secrets employed and understood in international cinema? In a new book, , associate professor in the Jackson School, explores the use of secrets in acclaimed films such as Guillermo del Toro’s “” and Alejandro Amenábar’s “,” in which Nicole Kidman starred.

Porter’s book “” was published in early 2018 by CRC Press. Publishers notes say the book “advances a methodological line of inquiry based on a fresh insight into the ways in which cinematic meaning is generated and can be ascertained.” The book analyzes the use of secrets in these films and more.

“It demonstrates how a rethinking of the figure of the secret in national film yields a new vantage point for examining heretofore unrecognized connections between collective historical experience, cinematic production and a transnational aesthetic of concealment and hiding.”

, a growing concept in film studies, considers films that span national boundaries.

To learn more, contact Porter at debzport@uw.edu

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Tool kit for urban observation promotes better planning, design

Personal observation remains an important way of understanding and improving cities, says Seattle-based attorney in his book “.” Wolfe is also an affiliate associate professor of urban design and planning in the 91̽��College of Built Environments, where he teaches land use law at the graduate level.

Notes from publisher Island Press say that Wolfe takes an “urban diary” approach to describe how city dwellers can “catalog the influences of urban form, neighborhood dynamics, public transportation, and myriad other basic city elements that impact their daily lives” and use such observations to improve planning and design decisions.

“This type of close, thoughtful looking is a way to snap out of the stupor of the daily grind and parse the details that are so easily overshadowed. But … it is also a way to think about how to shape the future,” says a on the Atlantic monthly’s website CityLab.

“Seeing the Better City” was an and was a in the United Kingdom for a National Urban Design Award from the nonprofit celebrating the best books on that topic.

To learn more, contact Wolfe at cwolfe@crwolfelaw.com.

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‘Rethinking’ youth media empowerment

How do queer youth use media for self-expression, connection and public visibility? Who is best equipped to participate in meaningful ways, and where might social inequities be reproduced in the process of production?

A new book by , assistant professor in 91̽��Bothell’s School of Interdisciplinary Arts & Sciences, combines three years of “” with young media makers in San Diego with textual analysis of many youth-produced videos and media campaigns. “” was published this summer by Routledge.

In this way, Berliner examines how media makers at the margins negotiate funding and publicity and strategically produce their online identities.

Publishers notes say the book “unsettles assumptions that having a ‘voice’ and gaining visibility and recognition necessarily equate to securing rights and resources.

“Through her study of youth media practices within larger contexts of history and pedagogy, Routledge says, Berliner “reframes digital media participation as a struggle for ― rather than, in itself, evidence of ― power.”

To learn more, contact Berliner at lsb26@uw.edu.

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91̽��faculty pen book chapters on environmental studies

A new textbook on environmental studies includes two chapters written by 91̽��faculty members. “,” published in May 2018 by Routledge, contains more than 150 short chapters written by leading international experts. Together they provide concise, authoritative and easy-to-use summaries of key issues, debates, concepts and current questions in environmental studies.

, a 91̽��associate professor of political science, authored a chapter on “Gaia.” Litfin is also the author of a 2014 book, “,” that describes a year of travels to sustainable communities around the world.

, a 91̽��professor emeritus of atmospheric sciences, authored a chapter on “Key Debates on Population and Global Demography.” The chapter covers issues such as causes of population growth, influence of education, demand for and access to contraception, and geographic variations. (Warren is also the author of a 2015 open-access academic on population growth issues.)

To learn more, contact Warren at sgw@uw.edu or Litfin at litfin@uw.edu.

, a 91̽��professor of oceanography, was recognized for his work using new technology to study the upper ocean. He earned his undergraduate degree in engineering and applied physics at Harvard University and his doctorate jointly from the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. Following a postdoctoral year at WHOI, he was on the MIT faculty until he joined the 91̽��in 1986.

In his research, Eriksen has collected observations to understand oceanic internal waves, equatorial and upper-ocean dynamics, eddies and general circulation using both conventional and custom instruments. He led development of the , an autonomous underwater glider that can be deployed for several months and travel thousands of miles in the upper ocean. More recently, Eriksen has led the development of the Deepglider, the only autonomous underwater vehicle capable of gliding to the seafloor and back in the deep ocean. Deepgliders are designed to last up to a year and a half and travel as far as a quarter of the way around the Earth.

, also a 91̽��professor of oceanography, was recognized for her studies of deep-sea environments. A Pacific Northwest native, Kelley earned her bachelor’s and master’s degrees in geology at the 91̽��and her doctorate at Canada’s Dalhousie University. She joined the 91̽��faculty in 1995. She also holds an adjunct position at the University of Bergen in Norway.

Kelley’s research focuses on the extreme environments of seafloor volcanoes and associated underwater hot springs, as well as the unique biological communities that live there. Her field work includes more than 30 research expeditions. She led a 2003 cruise to the “” hydrothermal vent field in the Atlantic Ocean. In 2015 she co-authored an of seafloor volcanoes and deep-ocean life, which won the Association of American Publishers 2016 Prose Award for Earth science books. Kelley is a lead investigator for the Pacific Northwest , a real-time seafloor observatory that connects the ocean to the internet. She has also traveled to the deep ocean firsthand more than 50 times, reaching more than 2 miles below the surface.

, a 91̽��professor emeritus of atmospheric sciences and of Earth and space sciences, was recognized for his research on the interaction of solar radiation with clouds, snow, sea ice and glaciers. Warren did his undergraduate degree at Cornell University and his doctorate at Harvard University before joining the 91̽��faculty in 1982. He was previously elected as a fellow of the American Meteorological Society and of the American Association for the Advancement of Science.

Warren has analyzed some 500 million visual observations of , taken from land-based weather stations and ships in the ocean, to create a global atlas showing the distribution of nine different cloud types. More recently, he has looked at how soot from forest fires and fossil-fuel burning gets and changes the reflectivity of snow and glaciers, speeding up global warming. He also has published on the “” hypothesis for how the oceans may have completely frozen over earlier in Earth’s history. Warren’s extensive fieldwork has brought him to Siberia, China and to Antarctica, where a mountain ridge is named after him.

The three 91̽��faculty members will be among new fellows who will be honored in December at the American Geophysical Union’s annual meeting in San Francisco.

A 91̽�� scientist is co-author on a new paper that tracks down why the ice sheet is darkening. The , led by Columbia University, was published March 3 in The Cryosphere.

“According to the satellites, Greenland is darkening by about 2 percent per decade since 1996,” said second author , a research scientist at the UW’s Joint Institute for the Study of the Atmosphere and Ocean. “That seems really small, but it’s actually climatically significant.”

Wildfires have been recently proposed as the of Greenland’s ice sheet, but historical records of fires during that period could not explain the changing reflectivity since the mid-90s, Doherty said.

The authors find instead that most of the darkening is a side effect of warming.

“The lion’s share of the darkening is driven by feedback to the snowpack optical properties,” Doherty said. The study shows that as the glacier melts, the snow crystals get larger and impurities surface – both processes familiar to anybody who has seen old, spring snow.

With warming each year’s snow melts completely to expose the darker glacier ice underneath, and there are more melt pools, which also darkens the surface.

“You don’t necessarily have to have a ‘dirtier’ snowpack to make it dark,” said lead author , a research professor at Columbia University.

Looking forward, the study concludes that continued warming will cause Greenland to absorb about 8 percent more sunlight by the end of this century, with bigger changes along its western edge.

The research draws on the by Doherty and , a 91̽��professor of atmospheric sciences. The team collected some 1,200 snow samples from Northern landscapes, including Greenland. Their follow-up looked at how impurities tend to accumulate at the surface as the snow melts.

By combining the on-the-ground observations with satellite images from 1981 to 2012 and computer models of glaciers, the new study shows the past two decades of darkening can be explained by larger crystals that reflect less sunlight and exposed impurities at the ice surface.

The research also draws on Warren’s earlier studies of and how affects polar landscapes.

For Greenland today it appears that warming, not deposited air pollution, is the primary culprit.

“Using satellites, models and other information to put some bounds on what is happening to the glacier’s surface and what’s causing it, our conclusion is that it’s not an increase in wildfires that is causing the darkening,” Doherty said.

That distinction matters, she said, because it means that regulating particulate emissions from diesels or reducing wildfire smoke would not save Greenland’s ice. Instead, the darkening is being driven by increased melting, which is caused by climate warming.

“There’s a potential for the Greenland ice sheet to contribute significantly to sea-level rise in the next 50 to 100 years,” Doherty said. When calculating future sea-level rise, she added, scientists need to be able to model all the processes that are significant.

“We now have a better understanding of what’s causing the darkening, and we know that it’s significant enough that we need to include it in our models.”

Other co-authors are Xavier Fettweis at Belgium’s University of Liege, Patrick Alexander at NASA’s Goddard Institute of Space Studies, Jeyavinoth Jeyaratnam at the City College of New York, and Julienne Stroeve at the University of Colorado. The research was funded by the National Science Foundation and NASA.

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For more information, contact Doherty at 206-543-6674 or sdoherty@uw.edu.

See also a Columbia University .

Authors of the paper, led by , a 91̽��research scientist in atmospheric sciences, set out to examine observations collected from weather stations around the world as a way to study the distribution of clouds. The research was recently published in the American Meteorological Society’s .

Among the many reasons that scientists study clouds are that cloud properties are expected to change with global warming and clouds have an impact on temperature and rainfall.

Eastman and co-author , a 91̽��professor of atmospheric sciences and of Earth and space sciences, found that from 1971 through 2009 cloud cover over land globally declined 0.4 percent per decade. That’s less of a decline than the 0.7 percent per decade that the pair found in a 2007 paper that examined data from 1971 through 1996.

Because scientists would need to examine much more data about changes in types of clouds at different altitudes at different locations in different seasons, it’s difficult to ascertain how important this change in cloud cover over land is.

“We do expect global cloud cover to respond to climate change, but this trend alone cannot be directly linked as a cause or result of global warming,” Eastman said.

The research was based on visual observation that doesn’t include information about important changes to cloud features like thickness or the ability to reflect light.

Visual observations do, however, shed light on some notable changes in cloud distribution.

For instance, the researchers found a significant poleward shift in the cloud cover associated with the mid-latitude storm track, often described as the jet stream, as well as a shift poleward in the dry, cloud-free areas over the subtropical deserts.

“Since these clouds are associated with the jet stream, it indicates the jet stream is also moving poleward,” Eastman said. “This supports other findings that the tropics are expanding with the shift in the jet stream.”

In 2006, 91̽��scientists were the first to that the jet stream was shifting, leading to an expansion of the world’s driest regions.

In their research, Eastman and Warren also discovered significant changes in clouds over Northern India that are consistent with a drying trend there. They found an increasing incidence of stratiform clouds and fewer cumuliform clouds. Stratiform clouds are low, horizontal clouds that form in sheets. They tend to produce light rain or drizzle and are less likely to produce heavy rain than cumuliform clouds, which are distinct, vertical clouds created by warm, moist air rising in turbulent updrafts.

The change could be caused by heavy pollution containing large amounts of black carbon in the area. Black carbon absorbs sunlight, creating a warming effect aloft while reducing the amount of sunlight that reaches the surface, cooling it. That stabilizes the atmosphere, creating an environment more conducive to the formation of stratiform than cumulonimbus clouds.

“We saw a shift in cloud types in this area, which supports models that show that pollutants are causing this change in the way clouds form and on precipitation,” Eastman said.

In northeastern China, which like India has also experienced droughts along with a large increase in pollution, the researchers were unable to identify a similar pattern. Instead, they found that the area is experiencing a slight decline in both cumuliform and stratiform clouds.

Eastman and Warren hope to continue analyzing the observations.

“Our goal is to keep this going so we can verify satellite measurements and support modelers in their work,” Eastman said.

The researchers face some challenges though.

“There are more than 100 countries, thousands of observers and millions of data points,” Eastman said. “You’re going to see some problems.”

For example, they detail anomalies they found with data from weather stations in Russia that appeared to show a dramatic change in clouds over some areas. When they examined data on other kinds of clouds observed from the same stations, they found that those clouds didn’t substantially change, which they regard as unlikely. The researchers also noticed that the dramatic changes in observed clouds occur in different years at different stations.

“We have not identified the cause for the spurious changes in cloud types shown here. It is most likely the result of an undocumented change in observing procedure or training at some stations,” they wrote in the paper.

Eastman and Warren also face a possible reduction in the overall volume of data they are able to collect. Some regions of the world, like the U.S. and Canada, are switching from human observations to machine observations.

“The data set has to be homogeneous,” Eastman said. That means the pair can’t incorporate data from North America in their reports.

The research was supported by the National Science Foundation.

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For more information, contact Eastman at 206-543-7180 or rmeast@atmos.washington.edu