Scars from seismic surveys for oil and gas exploration in the Arctic National Wildlife Refuge remained for decades, according to the study. The findings counter assertions made by the Bureau of Land Management in 2018 that seismic exploration causes no “significant impacts” on the landscape. That BLM determination would allow a less-stringent environmental review process of seismic exploration in the Arctic Refuge 1002 Area.

UAF’s Martha Raynolds, the lead author of the study, said she and other scientists have documented lasting impacts of winter trails throughout years of field research. Their paper, authored by an interdisciplinary team with expertise in Arctic vegetation, snow, hydrology and permafrost, summarizes what is currently known about the effects of Arctic seismic exploration and what additional information is needed to effectively regulate winter travel to minimize impacts.

A grid pattern of seismic survey lines is used to study underground geology. These trails, as well as trails caused by camps that support workers, damage the underlying tundra, even when limited to frozen, snow-covered conditions. Some of the existing scars on the tundra date back more than three decades, when winter 2D seismic surveys were initiated. Modern 3D surveying requires a tighter network of survey lines, with larger crews and more vehicles. The proposed 1002 Area survey would result in over 39,000 miles of tracks.

“Winter tundra travel is not a technology that has changed much since the ’80s,” said Raynolds, who studies Arctic vegetation at UAF’s Institute of Arctic Biology. “The impacts are going to be as bad or worse, and there are proposing many, many more miles of trails.”

Conditions for winter tundra travel have become more difficult, due to a mean annual temperature increase of 7-9 degrees F on Alaska’s Arctic coastal plain since 1986. Those warmer conditions have contributed to changing snow cover and thawing permafrost. The impact of tracks on the vegetation, soils and permafrost eventually changes the hydrology and habitat of the tundra, which affects people and wildlife who rely on the ecosystem.

The paper argues that more data are needed before proceeding with Arctic Refuge exploration efforts. That includes better information about the impacts of 3D seismic exploration; better weather records in the region, particularly wind and snow data; and high-resolution maps of the area’s ground ice and hydrology. The study also emphasizes that the varied terrain and topography in the 1002 Area are different from other parts of the North Slope, making it more vulnerable to damage from seismic exploration.

Other contributors to the paper included UAF’s Mikhail Kanevskiy, Matthew Sturm and Donald “Skip” Walker; Anna Liljedahl, UAF and Woods Hole Research Center; Janet Jorgenson, U.S. Fish and Wildlife Service; Torre Jorgenson, Alaska Ecoscience; and Matthew Nolan, Fairbanks Fodar.

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Animal groups exhibit the seemingly contradictory characteristics of being both robust and flexible. Imagine a school of fish: hundreds of individuals in perfect order and alignment can suddenly transition to a convulsing tornado dodging an attack. Animal groups benefit if they can strike this delicate balance between being stable in the face of “noise” like eddies or gusts of wind, yet responsive to important changes like the approach of a predator.

Critical transition

How they achieve this is not yet understood. But in recent years, a possible explanation has emerged: criticality. In physics, criticality describes systems in which a transition between states — such as gas to liquid — occurs at a critical point. Criticality has been argued to provide biological systems with the necessary balance between robustness and flexibility. “The combination of stability and high responsiveness is exactly what characterizes a critical point,” says the study’s lead author Clemens Bechinger, Principal Investigator in the Centre for the Advanced Study of Collective Behaviour and Professor in the Department of Physics at the University of Konstanz, “and so it made sense to test if this could explain some of the patterns we see in collective behaviour.”

The hypothesis that collective states are hovering near critical points has been studied in the past largely through numerical simulations. In the new study published in Nature Communications, Bechinger and his colleagues have given rare experimental support to the mathematical prediction. “By demonstrating a close link between collectivity and critical behaviour, our findings not only add to our general understanding of collective states but also suggest that general physical concepts may apply to living systems,” says Bechinger.

Experimental evidence

In experiments, the researchers used glass beads coated on one side by a carbon cap and placed in a viscous liquid. When illuminated by light, they swim much like bacteria, but with an important difference: every aspect of how the particles interact with others — from how the individuals move to how many neighbours can be seen — can be controlled. These microswimming particles allow the researchers to eschew the challenges of working with living systems in which rules of interaction cannot be easily controlled. “We design the rules in the computer, put them in an experiment, and watch the result of the interaction game,” says Bechinger.

But to ensure that the physical system bore a resemblance to living systems, the researchers designed interactions that mirrored the behaviour of animals. For example, they controlled the direction that individuals moved in relation to their neighbours: particles were programmed either to swim straight towards others in the main group or to deviate away from them. Depending on this angle of movement, the particles organized into either swirls or disordered swarms. And incrementally adjusting this value elicited rapid transitions between a swirl and a disordered but still cohesive swarm. “What we observed is that the system can make sudden transitions from one state to the other, which demonstrates the flexibility needed to react to an external perturbation like a predator,” says Bechinger, “and provides clear evidence for a critical behaviour.”

“Similar behaviour to animal groups and neural systems”

This result is “key to understanding how animal collectives have evolved,” says Professor Iain Couzin, co-speaker of the Centre for the Advanced Study of Collective Behaviour and Director of the Department of Collective Behavior at the Konstanz Max Planck Institute of Animal Behavior. Although not involved with the study, Couzin has worked for decades to decipher how grouping may enhance sensing capabilities in animal collectives.

Says Couzin: “The particles in this study behave in a very similar way to what we see in animal groups, and even neural systems. We know that individuals in collectives benefit from being more responsive, but the big challenge in biology has been testing if criticality is what allows the individual to spontaneously become much more sensitive to their environment. This study has confirmed this can occur just via spontaneous emergent physical properties. Through very simple interactions they have shown that you can tune a physical system to a collective state — criticality — of balance between order and disorder.”

Application areas

By demonstrating the existence of a link between collectivity and critical behaviour in living systems, this study also hints at how the intelligence of collectives can be engineered into physical systems. Beyond just simple particles, the finding could assist with designing efficient strategies of autonomous microrobotics devices with on-board control units. “Similar to their living counterparts, these miniature agents should be able to spontaneously adapt to changing conditions and even cope with unforeseen situations which might be accomplished by their operation near a critical point,” says Bechinger.

Key facts:

• Physicists from the University of Konstanz show a link between collective behaviour and a concept in physics known as criticality.
• Through experiments using tiny glass particles, they create collective states of swarms and swirls.
• Showing that the particles can make sudden transitions from one state to the other provides clear evidence for a critical behaviour
• Original publication: Bäuerle, T., Löffler, R.C. & Bechinger, C. Formation of stable and responsive collective states in suspensions of active colloids. Nat Commun 11, 2547 (2020). https://doi.org/10.1038/s41467-020-16161-4
• Authors include Tobias Bäuerle (lead author) and Robert Löffler, both doctoral students at the University of Konstanz. Senior author Clemens Bechinger is Professor of Physics at the University of Konstanz
• Clemens Bechinger is also part of the University of Konstanz’s Cluster of Excellence “Centre for the Advanced Study of Collective Behaviour,” which has been funded in the Excellence Strategy of the German Federal and State Governments since 2019.
• The research was supported by an ERC Advanced Grant ASCIR and the Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy — EXC 2117 — 42203798.
• campus.kn is the University of Konstanz’s online magazine. We use multimedia approaches to provide insights into our research and science, study and teaching as well as life on campus.

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These “stardust” grains arrived on Earth inside primitive meteorites. New Washington University in St. Louis research led by Nan Liu, an assistant research professor in physics and the Laboratory for Space Sciences in Arts & Sciences, shows that stardust was also delivered to another planet-like body in the solar system, asteroid 4 Vesta, by micrometeoroids that also carried water.

The research was published in the journal Geochimica et Cosmochimica Acta.

“Like our Earth,” Liu said, “Vesta has a core, a mantle and crust,” features that formed as the materials melted, differentiated and coalesced into a single planet-like object. And like Earth, Vesta is also pummeled by micrometeoroids. The brightest asteroid in the night sky, Vesta orbits the sun in the asteroid belt between Mars and Jupiter.

Liu, along with Lionel Vacher, a postdoctoral researcher, and Ryan Ogliore, assistant professor of physics, studied samples of the Kapoeta meteorite for this research. Kapoeta fell to Earth in 1942 in what is now South Sudan, landing on a road in front of a British convoy during World War II. NASA’s Dawn mission to asteroid Vesta established a link between Vesta and the howardites, eucrites and diogenites, groups of meteorites found on Earth.

The research team focused on small, dark inclusions in Kapoeta that seemed out of place, like pieces of clay in lava rock. “They look completely different from surrounding material,” Liu said. They turned out to be microscopic meteoroids, less than 100 microns across (smaller than the thickness of a human hair), that landed on Vesta’s surface.

Liu used the university’s mass-spectrometer microscope, the NanoSIMS, to search the inclusions for presolar material. Because stardust has a very different isotopic composition from material that formed within the solar system, it jumped out at her under the microscope.

The stardust in asteroid Vesta is a unique record of ancient, galactic material delivered long ago to a body far from Earth. The researchers postulate that the micrometeoroids arrived at Vesta after the violent impacts of the Late Heavy Bombardment, about 3.5 billion years ago.

Vacher and Ogliore measured the chemical compositions of the micrometeoroids to understand in what type of environment they formed. They recognized minerals and textures that were linked to interactions between rock and water from melted ice.

One of the big questions is: How did water get on Earth?

“We need a mechanism to bring ice from the outer solar system, where the temperature is low,” Vacher said. “This research shows that you can transport small micrometeoroids that contain ice to dry bodies that formed without water.”

The ancient record of these micrometeoroids impacting Earth has been erased by weather and plate tectonics. The micrometeoroid record from asteroid Vesta may help to explain how water was delivered to the young Earth.

“If icy micrometeoroids delivered water to the inner solar system when the Earth was still forming, this could be one way that the Earth ended up with enough water to support life,” Ogliore said. “Habitable planets around other stars may have acquired their water through similar means.”

More analyses are needed to determine the when and the where. “Our next measurements will constrain when this wet material was delivered to Vesta, and where it came from: an icy asteroid, a comet or some other exotic source,” Ogliore said.

Take a trip to 4 Vesta

You can zoom in on Kapoeta thanks to Ryan Ogliore, assistant professor of physics. He worked to develop techniques to visualize objects from the micrometer to the millimeter scale — that’s a factor of 1,000. “It’s like he took a puzzle with 1,000 pieces, but Ryan is doing the same puzzle with 10,000 pieces,” said Lionel Vacher, research assistant.

In this week’s interdisciplinary journal — Proceedings of the National Academy of Sciences, an international group of scholars show that gross domestic product (GDP) fails to fully capture nature’s contributions to economic activity and human well-being. In addition to the D — domestic, there needs to be an E for ecosystem. Gross ecosystem product (GEP) summarizes the economic value of nature’s contributions to humans.

Valuing nature’s contribution globally is a critical step to affording the world’s forests, grasslands, fertile soils, wetlands and biodiversity the protections and respect given to traditional economic powerhouses.

“We must bring ecosystem services to the business table for a sustainable future,” said Jianguo “Jack” Liu, director of Michigan State University’s Center for Systems Integration and Sustainability. “The world is losing a tremendous amount of its natural capital — clean water, biodiversity, sequestering greenhouse gases. It’s time we give people a way to understand what they stand to lose economically.”

Both GEP and GDP use accounting measures to estimate the economic value of goods and services. The group assigned GEP to western China’s Qinghai Province, which is known as the water tower of east and southeast Asia as it is the source of three major rivers. Qinghai also is a biodiversity hotspot that has suffered from population increases and overgrazing.

By applying new accounting to Qinghai’s natural capital, the group was able to not only put Qinghai’s ecosystems on a balance sheet, but also show only a third of the economic value generated in the province’s ecosystems was provided to its residents. The rest were exported to other provinces of China and other countries of the world. This demonstrates the importance of human-nature interactions not only within a place but also across adjacent and distant places on this metacoupled planet.

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