FIELD TRIP Some researchers trek along active fault lines, others launch drones into Category 4 hurricanes. Either way, it's time for an ...
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VOL. 103 | NO. 7 Gardening in Moon Soil
JULY 2022
Utah Rocks
Hot Springs Clues in Tibet
FIELD TRIP
Some researchers trek along active fault lines, others launch drones into
Category 4 hurricanes. Either way, it’s time for an adventure.
FROM THE EDITOR
Editor in Chief
Heather Goss, Eos_EIC@agu.org
Adventure Time Vice President,
AGU Staff
Strategic Communications and Marketing Joshua Weinberg
E
Editorial
very issue of Eos is for you, the explorer. Whether you’re
Managing Editor Caryl-Sue Micalizio
strapping into a helicopter to fly over a volcano, sifting Senior Science Editor Timothy Oleson
through data to find patterns, or reading through the Associate Editor Alexandra Scammell
latest science news, you’re dedicated to seeking the new and Senior Science Reporter Kimberly M. S. Cartier
News and Features Writer Jenessa Duncombe
wonderous.
Our July issue is all about that urge to set out on a voyage of Production & Design
discovery. Of course, that isn’t always possible to do in person, Assistant Director, Operations Faith A. Ishii
Production and Analytics Specialist Anaise Aristide
but Earth and space scientists are innovators when it comes Assistant Director, Design & Branding Beth Bagley
to bringing the world to our doorstep. In “An Unprecedented Program Manager, Brand Production Valerie Friedman
View Inside a Hurricane,” Gregory R. Foltz and colleagues write Senior Graphic Designer J. Henry Pereira
Multimedia Graphic Designer Mary Heinrichs
about their clever use of technology to get an incredible view Graphic Design Intern Audrey Rapp
from inside a category 4 storm: Turn to page 22 to read about
Marketing
this partnership with NOAA to develop the saildrone that
Assistant Director, Marketing & Advertising Liz Zipse
spent days surfing four-story-high waves inside Hurricane Sam—and how the scientists will Media Relations Specialist Camila Rico
use the data they collected to improve hurricane intensity forecasts.
Then we follow a class of students in their first trek into the field. An international team set Advertising
Display Advertising Steve West
out to deploy a seismic network in Sumatra, Indonesia, to learn more about the Sunda sub- steve@mediawestinc.com
duction zone, the source of devastating hazards in the region. Karen Lythgoe and her colleagues Recruitment Advertising recruitmentsales@wiley.com
from the Earth Observatory of Singapore and Universitas Syiah Kuala write about their work
in “Striking Out into the Field to Track Slip on the Sumatran Fault.” Science Advisers
Geodesy Surendra Adhikari
They recruited a team of students from their institutions—two of whom, Dian Darisma (left) Hydrology José Luis Arumi
and Wiwik Ayu Ningsih, are featured on this month’s cover—to get their hands dirty placing Natural Hazards Paula R. Buchanan
seismic nodes into the ground all around the Aceh region. Turn to page 30 to read about how GeoHealth Helena Chapman
Atmospheric and Space Electricity Kenneth L. Cummins
they approached the many challenges of this type of fieldwork, from explaining their research Space Physics and Aeronomy Jingnan Guo
to local police and village leaders (who often did not speak the same language) to leeches and History of Geophysics Kristine C. Harper
Planetary Sciences Sarah M. Hörst
tree cover that obstructed GPS signals to a pandemic and the perils of leaving instruments
Volcanology, Geochemistry, and Petrology Emily R. Johnson
unattended for an extended period of time. Cryosphere Michalea King
Next, let’s take our seismometers and head somewhere cooler: Greenland. Evgeny A. Podol- Science and Society Christine Kirchhoff
Seismology Ved Lekic
skiy writes about deploying seafloor instruments near a calving glacier front in “Arctic Uni- Mineral and Rock Physics Jie “Jackie” Li
corns and the Secret Sounds of a Glacial Fjord” on page 36. Glaciological processes can be dif- Tectonophysics Jian Lin
ficult to study, largely because deploying instruments close enough to monitor them is Near-Surface Geophysics Juan Lorenzo
Earth and Space Science Informatics Kirk Martinez
dangerous work. Read on to learn about how Podolskiy’s team at the Arctic Research Center Ocean Sciences Jerry L. Miller
in Hokkaido, Japan, managed to get their instrument to the bottom of Bowdoin Fjord, how Atmospheric Sciences Vaishali Naik
Study of the Earth’s Deep Interior Rita Parai
their hard work was saved by an Inuit whale hunter, and what their seismic data also told them Education Eric M. Riggs
about the notoriously reticent local wildlife—narwals. Global Environmental Change Hansi Singh
Finally, don’t put down the issue before reading the Opinion on page 19 by Marjorie Cant- Geomagnetism, Paleomagnetism,
and Electromagnetism Nick Swanson-Hysell
ine. “Playing it Safe in the Field” is an essential chapter in this issue dedicated to fieldwork. Paleoceanography and Paleoclimatology Kaustubh Thirumalai
Going out to have incredible, life-changing adventures and keeping yourself and your col- Nonlinear Geophysics Adrian Tuck
leagues safe should not be mutually exclusive pursuits. Cantine is leading one of a few efforts Biogeosciences Merritt Turetsky
Hydrology Adam S. Ward
to better understand—and thus be able to prepare for—dangers in the field. Diversity and Inclusion Lisa D. White
Once you have your adventures in the field and the lab and everywhere in between, remem- Earth and Planetary Surface Processes Andrew C. Wilcox
ber to come back and tell us about them. Begin telling your tales of how science really gets
done at eos.org/submit. ©2022. AGU. All Rights Reserved. Material in this issue may be photocopied by
individual scientists for research or classroom use. Permission is also granted to use
short quotes, figures, and tables for publication in scientific books and journals. For
permission for any other uses, contact the AGU Publications Office.
Eos: Science News by AGU (ISSN 0096-3941) is published monthly except December
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Heather Goss, Editor in Chief
Submit your article proposal or suggest a news story to Eos at eos.org/submit.
Views expressed in this publication do not necessarily reflect official positions
of AGU unless expressly stated.
Randy Fiser, Executive Director/CEO
SCIENCE NEWS BY AGU // Eos.org 1
CONTENT
30
22 36
Features
22 An Unprecedented View 30 Striking Out into the Field
Inside a Hurricane to Track Slip on
By Gregory R. Foltz et al. the Sumatran Fault
Intrepid saildrones ventured into several tropical By Karen Lythgoe et al.
storms, including the biggest of the 2021 Atlantic
The perils in maintaining an earthquake monitoring
hurricane season.
network in Sumatra’s active Aceh region.
On the Cover 36 Arctic Unicorns
Universitas Syiah Kuala students Dian Darisma (left) and
Wiwik Ayu Ningsih deploy a seismic node near the village of
and the Secret Sounds
Mane in Aceh, Indonesia. Credit: Karen Lythgoe of a Glacial Fjord
By Evgeny A. Podolskiy
A lesson in eavesdropping on narwals.
2 Eos // JULY 2022
CONTENT
6 42
8 43
Columns
From the Editor Research Spotlight
1 Adventure Time 42 Paired Gas Measurements: A New Biogeochemical
Tracer?
News 43 Hidden Upwelling Systems May Be Overlooked
Branches of Ocean Circulation | Nonlinear Effects
5 Lunar Soil Can Grow Plants of Wind on Atlantic Ocean Circulation
6 Million or Billion? Narrowing Down the Age of Mantle
Processes
8 Wildfire, Drought, and Insects Threaten Forests
Editors’ Highlights
in the United States 44 Is Earth’s Albedo Symmetric Between the
9 Rock Music in Utah Hemispheres? | The Need for Rational Thinking About
10 A New Index to Quantify River Fragmentation Human-Water Systems
12 Air Pollution Linked to Adverse Mental Health Effects
13 Cretaceous Charcoal Gives a Glimpse into Plant Positions Available
Evolution
45 Current job openings in the Earth and space sciences
14 Hot Springs Suggest How the Tibetan Plateau
Became the Roof of the World
16 A New Clue to Antarctic Ice Shelf Collapse
Postcards from the Field
17 How a Newly Discovered Mineral Might Explain Weird 48 Mat Microbes Dance to the Sun’s Beat
Mantle Behavior
Opinion
19 Playing It Safe in Field Science
AmericanGeophysicalUnion @AGU_Eos company/american-geophysical-union AGUvideos americangeophysicalunion americangeophysicalunion
SCIENCE NEWS BY AGU // Eos.org 3
NEWS
Lunar Soil Can Grow Plants
L
unar regolith is capable of growing
greenery, but plants grown in younger
lunar soil were less stressed than plants
grown in more mature soil. These experi-
ments were the first attempts to grow plants
in actual lunar regolith rather than soil sim-
ulant. The results, which were published in
Communications Biology, are a critical step in
understanding how future long-term resi-
dents of the Moon may be able to produce
their own food and oxygen through lunar
agriculture (bit.ly/lunar-soil-plants).
“It’s really good news that plants can grow
in the lunar soils,” said coauthor Robert Ferl,
a space biologist at the University of Florida
(UF) in Gainesville, during a press briefing.
The challenges that the plants experienced
showed that “there is some very interesting
biology, lunar biology, lunar biological chem- This Arabidopsis plant was grown in lunar soil for about 2 weeks. Credit: Tyler Jones, UF/IFAS
istry, that’s yet to be learned. But the bottom
line is that until it was actually done, nobody
knew whether plants, especially plant roots,
would be able to interact with very sharp, very some difficulty. Compared with the control and Earth soils tend to contain iron oxides
antagonistic soils that the lunar regolith samples grown in lunar simulant soil, plants that are easier for plants to access. Ionized
presents.” grown in actual lunar regolith had more iron results from interactions with the solar
stunted root systems, slower growth, and less wind, which explains why the most mature
extensive leaf canopies. They also exhibited soil, that from Apollo 11, grew the most
stress responses like deeper green or purple stressed plants.
leaf pigmentation. Although all of the plants “The simulants are incredibly useful for,
“It’s really good news grown in lunar soil were stressed, some were say, engineering purposes.… They’re won-
that plants can grow more stressed than others. Those grown in derful for determining whether or not your
Apollo 11 regolith were the most stressed, and rover is going to get stopped in the soil,” said
in the lunar soils.” those in the Apollo 17 regolith were the least coauthor Stephen Elardo, a planetary geo-
stressed. chemist at UF. “But when you get down to the
Although Apollo 11, 12, and 17 all landed in
basaltic mare regions of the Moon, the sites
The Moon Is Stressful exhibited some key differences. Regolith at
The researchers sowed Arabidopsis thaliana the Apollo 11 site is considered to be the most
(thale cress) seeds in small quantities of rego- mature soil of the three. The site has been
“The devil is in the details,
lith preserved from the Apollo 11, Apollo 12, exposed to the lunar surface the longest, and in the end the plants
and Apollo 17 landing sites, as well as in lunar which has led to the soil being weathered by
soil simulant. Arabidopsis plants, which are the solar wind, cosmic rays, and micromete-
are concerned about
related to mustards, cauliflower, broccoli, orite impacts. These maturation processes the details.”
kale, and turnips, have been grown in a wide can alter the chemistry, granularity, and glass
variety of soils and environments, including content of the regolith. The other two sites
in space. have also been “matured” by these processes
“It is edible, but it’s not especially tasty,” but to lesser extents, Apollo 17 least of all.
said lead author and plant biologist A nna- The team performed gene analysis on the chemistry that’s accessed by plants, they’re
Lisa Paul of UF. “We learn a lot that can be plants after 20 days of growth and found that not really one to one. The devil is in the
translated into crop plants from looking at the regolith-grown plants showed stress details, and in the end the plants are con-
Arabidopsis.” Moreover, Arabidopsis plants responses related to salt, metals, and reactive cerned about the details.”
are small and have a growth cycle of about a oxygen species. Those results suggested that
month, which is ideal when trying to grow much of the plants’ difficulty was related to Choose Your Resources Wisely
them in about a teaspoon’s worth of lunar the chemical differences between lunar rego- These results show that lunar regolith is
regolith. lith and lunar soil simulant, such as the oxi- capable of supporting the growth of plants,
The researchers found that all three lunar dation state of iron—lunar iron tends to be in which will be an integral component of any
soils were capable of growing plants, but with an ionized metallic state, whereas simulant long-term lunar habitat. Plants will be able
SCIENCE NEWS BY AGU // Eos.org 5
NEWS
Million or Billion? Narrowing Down
the Age of Mantle Processes
A
s tectonic plates jostle one another, subduction zone accommodating the disap-
collisions can cause the bottom of the pearance of the Pacific plate into the mantle,
ocean to end up on land. Formerly with a string of volcanoes poking above the
underwater sequences of oceanic crust and water. Eventually, these disparate pieces of
mantle, called ophiolites, help geologists not Earth’s surface—northern Australian frag-
only to disentangle the history of how these ment, spreading center, and volcanic island
rocks went skyward but also to discern past arc—collided, with the remnants of these
exploits of Earth’s mantle. events preserved in parts of New Guinea.
In a recent study published in the Journal of
Petrology led by Natasha Barrett while she was
a doctoral student at the University of Alberta,
Barrett and her team examined samples from
“In the Archean, the mantle
jungle-encased ophiolites collected more
than 40 years ago from Papua New Guinea, an was hotter, so you expect
island nation just north of Australia (bit.ly/
ophiolites-guinea).
to have more melting.”
The spreading center that produced these
ophiolites was likely erupting basalt seafloor
about 70–55 million years ago—around the
Anna-Lisa Paul harvests plants for genetic analysis. time the dinosaurs died. However, scientists Today, New Guinea—an island split
Credit: Tyler Jones, UF/IFAS suspected that the ophiolites’s lowermost between the countries of Indonesia and Papua
mantle rocks, which have strange geochem- New Guinea—peers above various Pacific
ical signatures, must have come from mantle seas. This scrap of mostly continental crust,
that melted eons before, likely during the which connects to Australia when sea level
to support key functions like water recycling; Archean, between 4 billion and 2.5 billion decreases, hides those ophiolites below its
carbon dioxide removal; and oxygen, food, years ago (when life was restricted to single- lush vegetation.
and nutrient production. c elled organisms). Barrett and her team
“It’s a well-organized and thought-out demonstrated that the ophiolites’ lowermost Unique Ophiolites
experiment to test growing plants in actual mantle is instead much younger and pro- If intrepid geologists came upon a complete
lunar regolith returned from the Apollo 11, 12, posed that it melted in a modern subduction ophiolite, they would walk through seafloor
and 17 missions,” said Edward Guinan, an zone setting, forcing petrologists to rethink sediments, lavas and intrusive igneous rocks
astronomer at Villanova University in Penn- how these geochemical signatures developed. of the crust, and mantle rocks called peridot-
sylvania who has conducted plant experi- ites that are rich in the greenish mineral oliv-
ments in Moon and Mars soil simulants. “As Leftovers ine. Barrett compared the lowest layer of
the authors point out, the test plants are Some scientists think that before the dino- mantle peridotite, which is what was left
stressed and don’t grow well. The plants have saurs’ demise, oceanic lithosphere hanging over after the mantle melted, to a squeezed
characteristics of plants grown in salty or off the northern edge of Australia plunged sponge, bereft of its water (the melt, in this
metal-rich soils. Maybe trying different ter- into the mantle, producing a trench and analogy). It is these rocks—equivalent to the
restrial plants that do well in poor or salty spreading center on the seafloor where new wrung-out sponge—that scientists expected
soils might be an interesting follow-up.” oceanic crust erupted. Past the proposed to be billions of years old.
Guinan was not involved in this research. spreading center may have been yet another In New Guinea’s ophiolites, the leftover,
This study also shows that although plants lowermost peridotites are unique in two
can be grown using in situ lunar resources, ways. First, they’re especially refractory,
where those resources come from will be which means they’re filled with elements,
important for the plants’ growth success. particularly magnesium, that don’t like to be
Regardless of where future lunar explor- in melts, said Marguerite Godard, a mantle
ers build a habitat, “we can choose where petrologist at the French National Centre for
we mine materials to use as a substrate for Scientific Research who is hosted at the Uni-
growth habitats,” Paul said. “It’s where the versité de Montpellier. Godard was not
materials are mined from that makes a dif- involved with this study.
ference, not where the habitat exists.” Second, these rocks lack many elements
already in low abundances in the mantle;
Scientists analyzed peridotites like this, from ophiolite these trace elements strongly prefer the melt,
By Kimberly M. S. Cartier (@AstroKimCartier), in Papua New Guinea, to better understand the com- depleting the residue. “Highly refractory [and
Staff Writer plex geology of the region. Credit: Natasha Barrett depleted] mantle means a lot of melting,”
6 Eos // JULY 2022
NEWS
A river threads its way through the green hills of Papua New Guinea. Credit: Alan & Flora Botting/Flickr, CC BY-SA 2.0 (bit.ly/ccbysa2-0)
Godard said. To get lots of melting, scientists to the age at which the melt parted ways with her colleagues proposed that this compli-
surmised that mantle temperature must have the peridotite in question. cated subduction zone setting created these
been high. “In the Archean, the mantle was The osmium signatures Barrett found are bizarre geochemical signatures in two
hotter, so you expect to have more melting,” much higher than those observed in Archean stages. The first stage involved melting. The
said Godard. “That’s why we expect—in the peridotites, which have similarly weird geo- second involved multiple processes in which
Archean—to have refractory rocks,” she more melting was aided by water, basalt
explained. “Nowadays, the mantle is not so from deeper below, or something else liber-
hot.” ated from the subducting slab underneath
Recent data from ophiolites near New The melt extraction ages the spreading center. Like adding salt to ice
Guinea, like those on the islands of New Cale- in the winter to lower its melting point,
donia and New Zealand, contain similarly are definitely not Archean. these additions to the mantle above the sub-
curious geochemical signatures, said Godard. ducting slab would facilitate the second stage
One possible explanation for the Oceania- of melting.
wide pattern posits that mantle in this region “They are definitely the most refractory
melted billions of years ago. chemistry. On the basis of these data, the and depleted peridotites I have ever, ever
melt extraction ages of the rocks in her study seen,” said Godard, referencing that these
Mantle Mystery are not Archean, she said. Instead, the man- rocks are not well studied in part because
To figure out just when the mantle melted tle below New Guinea melted sometime in the they’re difficult to get to. “The mystery is
(leaving behind the residual rocks in her recent past, although being more specific why,” she said. Barrett’s proposed second
study), Barrett turned to the r henium- than the Phanerozoic isn’t possible without stage of melting, she explained, “is extremely
osmium geochronologic system. Radioac- additional study, she added. important in the system to produce those
tive rhenium decays to osmium. Rhenium Because the melt extraction happened very refractory…and depleted compositions.”
strongly prefers the melt, whereas osmium when the mantle was no longer as hot as it
stays behind. Once the rhenium goes away via was during the Archean, “you have to find a
the melt, the residual rock’s osmium signa- mechanism” to so immensely deplete the By Alka Tripathy-Lang (@DrAlkaTrip), Science
ture is locked in. That signature corresponds residual peridotites, said Godard. Barrett and Writer
SCIENCE NEWS BY AGU // Eos.org 7
NEWS
Wildfire, Drought, and Insects Threaten Forests
in the United States
Wildfires like the Monument Fire, which burned in Trinity, Calif., in August 2021, may be aggravated by forest management practices. Credit: CalTrans
W
ildfire risk to forests across the Reworking Forest Offset Designs disturbance risk, but they’re potentially mak-
United States is set to increase by Forest offset protocols account for risks like ing that risk greater,” Cabiyo added.
a factor of 4, and tree mortality wildfire with buffer pools—unharvested Expressing similar concerns, Barbara Haya,
caused by other climate-induced factors like woodlands set aside to compensate for carbon director of the Berkeley Carbon Trading Proj-
drought, heat, disease, and insects is set to losses. But, Anderegg said, such buffer pools ect, said the protocols are creating “a perverse
at least double by 2099, new research shows. do not account for geographical heterogene-
“Forests in the western half of the U.S. ity, like wildfire risks in California being sig-
have the highest vulnerability to each of nificantly higher than those in Maine, or the
these risks,” said William Anderegg, an fact that risks like wildfire are likely set to “Not only are these
associate professor at the University of Utah increase owing to climate change.
and lead author of the paper, which was pub- Another technique the scientific commu-
[forest offset] protocols
lished in Ecology Letters (b it.l y/ i ncrease nity often suggests is controlled burning. But underestimating
-wildfire-risk). there’s a problem: Many of the forests, espe-
But risks are not confined to the West. cially those in the West, are part of forest off- disturbance risk,
There are wildfire risks in Florida and Georgia, set projects in California’s cap-and-trade but they’re potentially
as well as in parts of Oklahoma and Texas, and program. What this means, in essence, is that
insect and drought risks in the northern Great owners and managers of these forests are making that risk greater.”
Lakes states. incentivized not to burn because carbon cred-
Anderegg explained that researchers mod- its are dependent on the amount of carbon
eled burned areas depicted by satellite imag- these forests can hold.
ery and used forest inventory data to ascer- Bodie Cabiyo, a graduate research fellow incentive” for forest managers not to decrease
tain other climate risks like drought, heat, in the Energy and Resources Group at the carbon stock even when it is beneficial to do
disease, and insect-driven tree mortality. University of California, Berkeley, noted that so. “The offset protocols are in direct contra-
The paper provides insights for improving some of these forests have grown very dense diction with some work that’s being done in
forest conservation practices and underscores and now have a lot of carbon in them. Cabiyo California to manage forests more sustainably
an urgent need to reduce emissions to mitigate was not involved in the new research. to reduce fire risk,” she added.
the impacts of climate change, Anderegg said. “What worries me about the offset proto- Anderegg suggested that an investment
More specifically, it highlights design and cols is that they incentivize dense forests, framework that allows for management like
assessment flaws in climate policies like for which are at higher risk of disturbance,” he prescribed burns would work better for both
est carbon offsets. Anderegg and the other said. Although management techniques like forest conservation and carbon sequestration.
authors question the integrity of offset proj- thinning can protect against future distur-
ects and call for “rigorous forest climate risk bances, the protocols effectively penalize such
assessment” for policies and programs that actions because they reduce carbon stocks. “So By Rishika Pardikar (@rishpardikar), Science
rely on the potential of forests to store carbon. not only are these protocols underestimating Writer
8 Eos // JULY 2022NEWS
Rock Music in Utah
who followed established climbing routes up
to 120 meters (~400 feet) high to place seis-
mometers, which work like sophisticated
accelerometers, atop the rock formations.
Using photographs, drone footage, and seis-
mometer data, researchers created 3D models
of 10 of 14 rock formations they attempted,
noting fundamental frequencies of 0.8–15
hertz, or cycles per second, which were
inversely proportional to tower size. They
were unable to model four towers because of
camera exposure from bright sunlight and
hard-to-measure rotational movements, like
twisting.
“You can kind of think of a tower like a gui-
tar string that’s turned on its side,” Finnegan
said. “You play the guitar string, and it
vibrates and resonates at certain frequencies,
and we hear those frequencies.” Similarly,
the towers vibrate at certain frequencies,
though they can’t be heard in the field.
Researchers created amplified audio record-
ings of the towers along with their 3D models.
Predictive Modeling
with Seismic Potential
Scientists tracked the natural frequency of the Secret Spire rock formation near Moab, Utah. Credit: Geohazards Along with measuring frequencies, mode
Research Group, University of Utah shapes, and damping ratios (a measurement
of the decrease in swaying motion over time)
in the 14 structures, Finnegan and her team
gathered frequency data and tower heights
I
t’s easy to think of Utah’s statuesque red able landforms,” Finnegan said. She hopes from prior studies and consulting reports for
rock towers as immobile, even immovable. the data will be used not only to predict the
Yet the rock towers imperceptibly twist, impacts of natural disasters and h uman-
rock, and sway in response to vibrations and caused vibrations but also to preserve the
seismic activity. stunning structures. Scientists partnered with
Recently, University of Utah geophysics “These data provide inputs for under-
graduate student Riley Finnegan measured standing how these landforms might respond
accomplished rock
the ambient vibrations of 14 large-scale to blasting work that’s done for building climbers who followed
structures in southern Utah, then included roads or other inputs for vibrational damage
these measurements in a new data set of assessments or risks,” Finnegan said. established climbing routes
32 similar structures in Utah and beyond. The to place seismometers atop
study was published in Seismological Research Rock Climbers Assist in Gathering Data
Letters (bit.ly/Utah-vibrations). Prior research uncovered the impact of vibra- the rock formations.
“What [the researchers have] really done tions from helicopter flights on the Utah
is to help us have confidence in our predic- structures, and similar studies measured the
tions about the specific frequencies at which natural frequency of mountains. Such mea-
these rock towers will resonate,” said Devin surements inform seismic risk assessments structures elsewhere in Utah, as well as in
McPhillips, an earthquake geologist with the as well as risks from other types of vibrations. Arizona, France, and Israel. Combining the
U.S. Geological Survey who was not involved But gathering measurements is challenging. compiled data with their own measurements,
with the study. “The individual data for each feature can they confirmed a formula for determining a
In addition to vibrational risk assessment, be incredibly hard to obtain, usually involving structure’s fundamental frequency given its
the rock towers have spiritual and cultural technical climbing,” said Jeff Moore, a coau- width, height, and composition. Using that
significance for the first occupants of these thor of the new study. relationship, researchers found they could
lands, including members of the Eastern Sho- For the current study, scientists partnered roughly predict the natural frequency of
shone, Hopi, Navajo, Southern Paiute, Ute, with accomplished rock climbers led by coau- unfamiliar sandstone or conglomerate rock
and Zune tribes. “These are culturally valu- thors Kathryn Vollinger and Jackson Bodtker, structures.
SCIENCE NEWS BY AGU // Eos.org 9NEWS
Researchers hope this confirmation will
help others predict the dynamic and reso-
A New Index to Quantify
nance properties of other rock towers without
challenging climbs; the calculation requires
River Fragmentation
only width and height measurements that
R
can be taken from the ground. ivers are fragmented by large and small tification allows policymakers to better eval-
“If we know something about the compo- dams the world over, be it for power uate development plans such as site selection
sition of the feature and we know about its generation, water supply, or flood con- for dam building and the effects of dam
shape, we can make a pretty good guess about trol. Direct impacts of such fragmentation removal on restoration.
what the fundamental frequency will be,” include barriers to sediment and nutrient The researchers applied the indices to two
McPhillips said. And such seemingly basic flow and isolation of fish populations. To bet- contrasting case studies: the Klamath River
ter quantify river fragmentation, researchers in California, where not only has dam build-
have designed a novel index, the catchment ing ceased but also dam removal has begun,
area–based fragmentation index (CAFI), as and the Netravati River in the state of Karna-
described in a paper published in Ecological taka, southern India, where 65 dams are pro-
Indicators (bit.ly/river-fragmentation). posed for development. CAFI was applied to
In contrast to current methodologies that the Klamath, and CARFI was applied to the
determine river fragmentation on the basis Netravati, which flows through the moun-
of river length, CAFI and its derivative, the tainous landscape of the Western Ghats.
rainfall-based fragmentation index (CARFI), The researchers found that river fragmen-
use catchment area as an indicator of the tation on the Klamath went through three
extent of river habitat. distinct phases. Dam construction between
Suman Jumani, a freshwater ecologist at 1840 and 1910 led to minimal fragmentation
the University of Florida and lead author of across the basin because the dams were
the new study, said that catchment area is a located on headwater streams that had rela-
good predictor of the volume of water flow- tively small catchment areas. Between 1920
ing in a stream. In addition, she added, a and 1960, as dams were increasingly located
catchment is relatively easy to quantify, so it downstream or closer to the main stem of the
“works well as a proxy for in-stream habitat river, larger catchment areas were affected,
availability.” resulting in higher basin-wide fragmenta-
tion. River fragmentation on the Klamath
Robust Contribution to Quantifying took another shift during the decade between
Fragmentation
Climbers descend Eagle Plume Tower in Utah after The new index provides a robust analysis of
placing seismometers atop the rock formation. river connectivity, a crucial measurement of
Credit: Eric Albright healthy rivers with aquatic biodiversity, The new quantification
researchers said.
Both CAFI and CARFI can be used to quan-
allows policymakers
tify how rivers are fragmenting in size and to better evaluate
measurements can have wide-ranging impli- over time. Catchment areas increase in size
cations, from refining earthquake hazard as rivers move downstream, and dams posi- development plans
models to developing building codes in tioned farther downstream in watersheds are such as site selection
regions prone to seismic activity, like the expected to cause greater habitat fragmenta-
Pacific Northwest. Such predictability tion. CAFI and CARFI can account for the for dam building and the
becomes even more important when scien- wildly different effects of dams depending on effects of dam removal
tists like McPhillips are tasked with predicting where they are built, whereas indices are less
outcomes in regions that have never recorded suited to differentiating the fragmentation on restoration.
megathrust earthquakes. effects between dams located at upstream
“Extrapolating from the limited historic and those at downstream positions in water-
data we have is potentially dangerous,” sheds.
McPhillips said. So data like Finnegan’s offer CAFI works well in areas where rainfall is 2002 and 2012, when eight small dams were
some added certainty and predictability. “If we largely uniform, whereas CARFI incorporates removed from tributaries. Fragmentation
know how old these rock towers are and we can rainfall intensity in addition to catchment decreased and is set to decrease further if
estimate how much shaking they can sustain, area, making it useful in mountainous land- plans to remove four more large dams from
we can put a maximum value on the strength scapes where precipitation is highest at the the main stem Klamath River proceed.
of past shaking, and that’s really helpful for ridge and reduces as streams flow downslope. As for the Netravati, researchers found a
refining earthquake hazard models.” “steep increase” in fragmentation after 2010,
Comparing California and Karnataka attributed largely to the construction of five
Essentially, the indices track how individual new dams along the main channel of the
By Robin Donovan (@RobinKD), Science Writer dams affect river fragmentation. This quan- river. Future dam construction will further
10 Eos // JULY 2022NEWS
paper, listed some of those challenges as
large-scale sand mining, deforestation, and
dishonest environmental impact assess-
ments. “We have to look at the totality of what
is happening across a river’s basin,” he
stressed.
In fact, Thakkar said, the 65 small hydro-
power dams on the Netravati analyzed in the
new paper don’t require environmental impact
assessments at all. These dams produce fewer
than 25 megawatts of power, and in India,
hydropower facilities that produce fewer than
25 megawatts are classified as renewable
Dam development on the Netravati River in southwestern India was evaluated by a new index measuring river energy projects and are exempt from environ-
catchment. Credit: Divya Jose T/Wikimedia, CC BY-SA 4.0 (bit.ly/ccbysa4-0) mental impact assessments. “There are no
assessments for such projects, no public hear-
ings, no monitoring and compliance. So how
can such indices help?” Thakkar asked.
increase basin-level fragmentation, the barrages and navigation locks, as well as the Verma, on the other hand, noted that sci-
paper found. development of canals and tunnels. entists and policymakers need such studies to
The indices are particularly suited to devel- “have proper scientific assessment of what all
Challenges of River Conservation oping countries in the tropics, which hold we are looking at when we deal with multiple
in India massive potential for future dam develop- barriers to water flow in rivers.” Nevertheless,
Jumani and her coauthors emphasized that ment. These regions are often data deficient, she added, it is true that more ground-level
CAFI “does not replace” ground-level or even but with CAFI and CARFI, “catchment area can information would make the study stronger,
project-specific impact assessments. From a be delineated with any surface elevation model and this point is “well-flagged” in the paper.
policy perspective, “this is key, because on a GIS platform and rainfall can be ascer- Jumani and the other authors maintained
though the indices capture a lot [of data], the tained through global datasets such as World- that the indices are part of a set of tools for
nuances remain to be supplemented,” said Clim,” the paper notes. river governance and not intended to be used
Avli Verma, a researcher at Manthan Adhya Other researchers disagreed about the util- in isolation. “This index, like most other
yan Kendra, a nonprofit investigating water ity of the new indices. In particular, the scope works of science, is not intended to solve or
and energy development in India. She did not of data offered by CAFI and CARFI is very lim- address the gamut of river governance
contribute to the new research. ited in a country like India, where challenges issues,” she said.
In India, Verma said, the indices could help to river governance are not just data driven,
inform decisions related to emerging river said Himanshu Thakkar, a coordinator at the
interventions. Examples of interventions South Asia Network on Dams, Rivers and Peo- By Rishika Pardikar (@rishpardikar), Science
include demolitions and reconstructions of ple. Thakkar, who did not contribute to the Writer
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SCIENCE NEWS BY AGU // Eos.org 11NEWS
Air Pollution Linked to Adverse Mental Health Effects
A
mental health crisis is brewing chology at Duke University who was not Animal-based research can tell scientists
among children and teens, and new involved in the study. “For people concerned only so much. After all, depression in a rat
evidence has suggested that exposure about understanding individuals’ risk for looks very different from depression in a
to air pollution could be one of many risk fac- depression, I think this paper adds a lot of human being. That’s why these findings are
tors (bit.ly/pollution-mental-health). In a new value.” often used in conjunction with observational
recent study, researchers found that adoles- studies, like Manczak’s, to understand how
cents living in areas with relatively high lev- “Humans Are Messy Subjects” these physiological mechanisms could affect
els of ozone experienced a significant uptick Scientists have long known that air pollution people, especially vulnerable populations
in depressive symptoms, such as sadness, exposure can lead to a slew of negative health like children.
loneliness, and feelings of self-hatred. effects, but “it was assumed for many years It’s not a perfect science, though. For one,
that air pollution mostly harmed the lungs,” “humans are messy subjects,” explained Reu-
explained Reuben. Even today, ozone is fre- ben. “Almost everything in human toxicology
quently said to contribute to pulmonary issues studies is going to be correlational.”
“One of the things like asthma and respiratory infections, “which There also could be other factors coming
it does, but then we realized: Maybe it could into play that researchers cannot easily control
that I’m pretty startled by also harm organ systems closely associated for. “In highly urbanized areas, it’s more likely
is that we’re seeing with the lungs.” that there are colocalizations of other environ-
That, it turns out, includes the brain and mental factors such as noise exposure, light,
these effects over central nervous system. “There seems to be or temperatures, which we know affect mental
2-and 4-year periods.” some evidence in animal models to suggest health,” explained Hahad.
that exposure to ozone and other forms of pol-
lution can affect the activity of various neu- Taking Precautionary Action
rotransmitters, as well as can encourage the Nevertheless, the research by Manczak and
expression of inflammatory proteins in the colleagues adds to the growing list of evidence
And this change in mental health can come brain,” explained Manczak. that highlights air pollution’s negative effect
about rather quickly, explained the study’s All of those things have been separately on mental health. “I think replicating the
lead author, Erika Manczak, an assistant pro- implicated in the formation and development study in a much larger sample and in different
fessor of psychology at the University of Den- of mental disorders, said Omar Hahad, a psy- parts of the world would be really an important
ver. “One of the things that I’m pretty star- chologist and researcher at the University next step to help us be a little bit more confi-
tled by is that we’re seeing these effects over Medical Center Mainz in Germany who was dent in these associations,” Manczak said.
2- and 4-year periods.” Perhaps even more not involved in the study. In addition, more work is needed to under-
unexpected: All of the study’s 213 participants stand how different mixtures of pollutants
lived in neighborhoods where average ozone might alter these effects. “We don’t know if
concentrations were below the National the effects of these air pollutants are additive
Ambient Air Quality Standards. “Even though or synergistic,” said Hahad.
these were objectively low levels of average Despite these outstanding questions, the
ozone exposure, we are nonetheless seeing public can still take precautionary actions,
these effects.” researchers said. “I’m a really big believer in
To conduct this study, which was pub- paying attention to what your local air qual-
lished in Developmental Psychology, Manczak ity is and using that information to inform
and colleagues analyzed mental health data how you behave across the day,” said Man
of children between the ages of 9 and 13 col- czak, whether that be rescheduling outdoor
lected at several points over a 4-year period. activities on high-pollution days or donning
They then compared these figures with air N95 masks.
quality monitoring data that roughly corre- That said, individual efforts can get us only
sponded to each participant’s home address. so far. “What is really lacking [are] the politi-
After accounting for a range of compounding cal actions to really address this problem,”
factors—like age, gender, and socioeco- said Hahad.
nomic status—the researchers found that Reuben agreed. “Fundamentally, when we
even slightly elevated ozone levels corre- talk about air quality, water quality, things
sponded with an increase in depressive that influence health and longevity of all of
symptoms over time. us, it has to be a societal response. You just
“They were able to show really clean linear can’t do it alone.”
symptom trends in folks exposed to high
levels [of ozone] that are basically absent in
folks not exposed to high levels,” said Aaron By Krystal Vasquez (@caffeinatedkrys), Science
Reuben, a postdoctoral scholar in neuropsy- Writer
12 Eos // JULY 2022NEWS
Cretaceous Charcoal Gives a Glimpse into Plant Evolution
T
o understand Earth’s remote past, pale-
ontologists and geologists look for ves-
tiges of history hidden in rocks. They
also look for clues of life in less obvious mate-
rials such as ages-old charcoal, which can
reveal how the global environment changed in
the deep past and give a glimpse into how it
might change in the distant future.
Recently, a team of researchers from Bra-
zil, Germany, and India identified rare char-
coal records of paleowildfires in the Sau-
rashtra Basin in Gujarat, northwestern India.
The material, said lead author Gisele Sana
Rebelato, dates back to the Early Cretaceous
(145–100 million years ago), a time when the
supercontinent Gondwana was drifting
apart. The paper was published in Current
Science (bit.ly/charcoal-records).
“Whenever we talk about South America,
Africa, Antarctica, India, and Australia, we’re
talking of our geological ‘backyard,’ as they
were all together in Gondwana,” said coauthor
André Jasper, who works with Rebelato at the
University of Vale do Taquari (Univates) in
Brazil.
In analyzing the charcoal with both a ste-
reomicroscope and a scanning electron micro-
scope, the team identified charred wooden
remains of gymnosperms, the flowerless
plants such as conifers and cycads that domi-
nated Earth until the Cretaceous, when they This image, taken with a scanning electron microscope, documents Cretaceous era charcoal found at the Than
were outcompeted by angiosperms. “It was Formation in Saurashtra Basin, Gujarat, India. Credit: Gisele Sana Rebelato
during this period,” Rebelato explained, “that
angiosperms, or flowered plants, emerged and
expanded, in part because of fire-altered bio-
logical dynamics. As [angiosperms] had a quite that—and there are few descriptions from and geological changes across the globe.
short life span, one of the hypotheses is that Gondwana,” Jasper said. [Scientific] work that analyzes the elements
wildfires ended up favoring them, as they grow that witnessed these changes, such as fossil
and recover quickly.” records, enables a better understanding of
The new research did not definitively con- the Earth system as a whole.”
firm that hypothesis, in part because it lacked “For fire to have been an Paleowildfires during the Cretaceous in
fossilized plants to analyze. “When we look at places like Antarctica and Patagonia, Manfroi
charcoal, we’re normally looking at wooden evolutionary driver, it must said, point to “significant climate and envi-
structures, which is what can actually fossil- have occurred globally, ronmental changes that climaxed in one of
Opposite : Aliazimi/Wikimedia, CC BY-SA 3.0 (bit.ly/ccbysa3-0)
ize. And [during the Late Cretaceous] angio- the Earth’s great extinctions but also show
sperms were mostly herbaceous; they didn’t not just in isolated places.” the relevance of fire to the evolution of veg-
have wood that could be preserved. So it’s etal groups that dominate terrestrial environ-
hard to make any straight correlations for ments today, such as the angiosperms.”
now,” Rebelato said. Manfroi, who has worked with the Brazil-
The study, however, advances science Wildfire as Part of a Broader ian authors before but did not take part in this
another rung on the ladder of understanding Earth System study, said the study of paleowildfires helps
paleowildfires as global phenomena. “There According to Joseline Manfroi, a paleobiology us understand “not just the frequency and
were wildfires in other regions, such as Eur- researcher at the Chilean Antarctic Institute, environmental conditions in which these
asia and the Americas. For fire to have been the new study is important to the geosciences phenomena occurred, but above all the rela-
an evolutionary driver, it must have occurred because the Cretaceous “represents a crucial tion of fire as a perturbing and changing agent
globally, not just in isolated places. So every moment in Earth’s geological history, having for different ecological niches in the past.
study of this kind adds more evidence to been the stage for significant environmental [Fire] contributed to configuring the diversity
SCIENCE NEWS BY AGU // Eos.org 13NEWS
and biogeography of flora in different lati-
tudes of the globe.”
Hot Springs Suggest How the Tibetan
Paleobotanist Ian Glasspool, a research
associate in geology at Colby College, said
Plateau Became the Roof of the World
ancient wildfires “aren’t just localized,
T
destructive, natural events but are also an he Tibetan Plateau has long repre- a spring that was surrounded by swamps, they
integral part of the broader Earth system.” sented both an opportunity and a hired a local guide to show them a relatively
Their list of impacts is extensive, Glass- conundrum for geophysicists. This vast dry route. Misunderstanding their destina-
pool explained, ranging from deep feedback tableland is the product of a long, slow colli- tion, the guide drove them to a different
on the global carbon cycle to influences in sion between the Indian and Eurasian conti- spring, about 80 kilometers from the nearest
nearshore marine sedimentology through nental plates—a collision that began about town, that wasn’t on any map or in any list of
changes in runoff and erosion. Wildfire has 50 million years ago and is still going on springs the researchers had seen. The feature,
a “feedback role in stabilizing the Earth’s today. As the only active continental colli- new to the scientists, “was like one of the big
atmospheric oxygen concentration” and acts sion site in the world, the plateau provides a springs in Yellowstone, with terraces and
“as a ‘global herbivore’ through its impacts unique opportunity to understand what hap- travertine and orange and yellow and white,
on vegetation. [It] preserves organic mate- pens when continents meet. But the long spanning a kilometer,” Klemperer said.
rial; charcoal produced by fires is chemically time frame and the great depths over which “One can still be an explorer, even today,”
inert, structurally rigid, and may preserve the collision has been occurring have left sci- he added.
exquisite cellular, and even subcellular, entists puzzling over how exactly the plates Sometimes the scientists failed to find
are coming together. springs that had been recorded in historical
In one model, the Indian plate is slipping lists (“travelers’ tales, or maybe they just
neatly underneath Asia, forming two parallel dried up,” Klemperer suspected). Other
layers like a cake with two tiers. In the other, times, they found that the springs had
Ancient wildfires “aren’t the collision has caused the Indian plate to acquired diverse uses. One had been con-
just localized, destructive, take an abrupt turn toward Earth’s core, leav- verted to a laundry facility for the Indian
ing the Eurasian (or Asian) plate directly on army, and many had become religious sites.
natural events but are also top of Earth’s mantle. Scientists have long All together, the team collected samples from
an integral part of the analyzed the composition of Tibet’s surface 225 springs across a thousand-kilometer-
rocks, as well as the area’s volcanic and seis- wide region.
broader Earth system.” mic activity, to discern which model is closer
to the situation found today. Isotope Fingerprints
Simon Klemperer, a geophysicist from Earth’s layers contain characteristic ratios of
Stanford University, and his colleagues the helium isotopes 3He and 4He, giving each
t hree-dimensional anatomy,” said Glass- decided to take a page from geochemists’ layer “a specific fingerprint,” said Dennis
pool, who did not take part in the study. playbook to learn how the Tibetan Plateau Newell, an isotope geochemist at Utah State
The study of ancient wildfires “has gained the nickname “the roof of the world.” University who was not involved with the new
become an integral factor in modeling Pha- Over the better part of the past decade, the research.
nerozoic atmospheric oxygen concentration, researchers analyzed helium isotopes in
for example. Fire may perturb ecosystems, water collected from more than 200 geother-
particularly where peats are burned; the mal springs to discern from which layer of
resultant tree mortality can be extreme,” the Earth the water emanated. The team’s
Glasspool continued. results, published in the Proceedings of the
“One can still be
“Unfortunately,” Jasper warned, “the National Academy of Sciences of the United States an explorer, even today.”
planet is burning right now. And we’re map- of America, suggest that the Indian plate
ping this kind of event across time and see plunges deeply beneath the Asian plate, but
[that] the consequences on life and biodiver- experts in the field say that many questions
sity are not to be taken lightly.… These still remain (bit.ly/collision-India-Asia).
[wildfire] events were followed by mass When Klemperer and his colleagues ana-
extinctions.” A Journey Across the Roof of the World lyzed the helium isotope ratios in their water
“The problem is that we’re accelerating a Klemperer and his colleagues teamed up with samples, a stark trend appeared: Samples
process that would take thousands or hun- a group led by Ping Zhao from the Chinese collected in the northern plateau had high
dreds of thousands of years to happen,” Academy of Sciences. They collected samples ratios of 3He/ 4He (as one would expect if
added coauthor Ândrea P ozzebon-Silva, also from across a sprawling area equivalent in Earth’s mantle directly underlies that region),
a researcher at Univates. “If reduced to cen- size to the contiguous United States west of whereas samples collected farther south had
turies or decades, the effects of wildfires can the Rockies, traveling by car, by motorbike, lower ratios.
be deleterious to humans and Earth’s biodi- and on foot and traversing dirt roads, rivers, The findings support the idea that the
versity at a scale not seen before.” and canyons to find the springs. Indian plate plunges deep below the Eurasian
The researchers often relied on locals to plate after the two collide beneath the Hima-
help them, occasionally with surprising layas. In fact, Klemperer has enough confi-
By Meghie Rodrigues (@meghier), Science Writer results. Once when they were trying to reach dence in his team’s results that he said, “I
14 Eos // JULY 2022NEWS
odern-day Tibetan Plateau. He pointed out
m
that helium isotopes take time to move from
the layers underlying the plateau to the sur-
face, where the researchers collected them.
Klemperer and his colleagues wrote that this
“I honestly believe that
textbooks will no longer
show two different models
of Tibet.”
transit takes place over a few millennia—a
quick time frame, geologically speaking. “I
would argue that it’s not established in this
paper that these things are moving as fast as
a millennia,” Newell said. “When I see this,
Geochemical analysis of hot springs like this one is helping scientists understand how subduction works beneath I don’t see today. I see a bit of a shadow of
the Tibetan Plateau. Credit: Ping Zhao the past.”
Tremblay and Newell both emphasized that
the study represents an impressive body of
work and provides a wealth of new informa-
honestly believe that textbooks will no longer But she thinks geoscientists still need infor- tion about an important geological region.
show two different models of Tibet.” mation about the past to round out their “Now it’s out there, and all of us as a commu-
Purdue University noble gas geochemist understanding of this region’s history. “This nity can think about it and think about alter-
Marissa Tremblay, who was not involved with is a snapshot of what things look like today. native hypotheses,” Newell said. “And that’s
the research but has collaborated with some And I think over the millions and millions of what we do!”
of the authors on other projects, said Klem- years that this collision has been ongoing, this
perer’s results are in line with studies that might have looked very different,” she said.
draw on surface geology and volcanic activity Newell isn’t as convinced that Klemper- By Saima Sidik (@saimamaysidik), Science
to discern how the Tibetan Plateau formed. er’s results show what’s happening on the Writer
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SCIENCE NEWS BY AGU // Eos.org 15You can also read
