At the microbiological level, life can be described as belonging to one of three kingdoms — how species are described in relation to one another. Eukarya contains complex organisms like animals and plants and microorganisms such as fungi. The other two categories, bacteria and archaea, are comprised only of microorganisms. Archaea are prevalent in a range of environments, from some of the most hostile like volcanoes and permafrost. However, archaea are also common in the human microbiome and as an important part of soil ecology.

“As temperature is a major driver of biological processes, climate warming will impact various ecological communities,” Zhou said. “Based on long-term time-series data, our previous studies revealed that experimental warming leads to the divergent succession of soil bacterial and fungal communities, accelerates microbial temporal scaling, reduces the biodiversity of soil bacteria, fungi and protists, but increases bacterial network complexity and stability. However, how climate warming affects the temporal succession of the archaeal community remains elusive. Archaea are ubiquitously present in soil and are vital to soil functions, e.g., nitrification and methanogenesis.”

Using a long-term multifactor experimental field site at OU’s Kessler Atmospheric and Ecological Field Station, the researchers showed that experimental warming of a tallgrass prairie ecosystem significantly altered the community structure of soil archaea and reduced their taxonomic and phylogenetic diversity. In contrast to the researchers’ previous observations in bacteria and fungi, their finds show that climate warming leads to convergent succession of the soil archaeal community, suggesting archaeal community structures would become more predictable in a warmer world.

Because contrasting societal views have created an approach that simultaneously manages horses on the range as wildlife, livestock and pets, current government programs are incapable of succeeding, the researchers argue in the article that appears in the journal BioScience.

“For the federal government to sustain healthy populations, ecosystem health and fiscal responsibility, lawmakers must properly define how feral equids should be labeled,” the scientists wrote. “Each label (wild, livestock, pet) has validity, and management plans can be implemented to optimize equid populations with other land uses. Furthermore, providing a clear definition of feral equids will determine the legal tools that can be applied for their management.”

The lead author of the paper is Jacob Hennig, a former UW Ph.D. student who is now a postdoctoral researcher at Oklahoma State. Hennig’s advisers at UW — Professor Jeff Beck and Associate Professor Derek Scasta, both in the Department of Ecosystem Science and Management — are co-authors of the paper. So are Oklahoma State Professor Sam Fuhlendorf and Assistant Professor Courtney Duchardt, who is a former UW Ph.D. student; Colorado State University research scientist Saeideh Esmaeili, also a former UW Ph.D. student; and Tolani Francisco, of Native Healing LLC in New Mexico.

The researchers note that, while the fossil record shows there were horses in North America previously, they went extinct about 10,000 years ago.

“The equids currently inhabiting North America did not coevolve there; they are descendants of livestock that underwent millennia of domestication and artificial selection,” the paper says. “Most large predators that would help limit their population growth went extinct at the end of the Pleistocene (epoch), and the Anthropocene (current epoch) has led to further predator reductions.”

Because wild horses have no natural predators, cannot be legally hunted under federal law and are no longer slaughtered as livestock in the United States, their numbers on the range have more than doubled in the last decade, the researchers say. They also note that horses removed from the range by the Bureau of Land Management (BLM) and held in government facilities and private lands have grown in number by 33 percent during that time, with the BLM spending over $550 million since 2013 supporting the captive animals.

“The BLM has increased the number of individuals removed from the wild in each of the past four years, leading to decreases in the on-range population,” the paper acknowledges. “However, the total on-range population is still approximately 50,000 individuals above the maximum (appropriate management level), and the recent moderate decrease in on-range individuals is directly correlated with an increase in the off-range population and subsequent expenditures.”

Removing wild horses from Western rangelands and placing them in long-term holding is not a solution, the researchers say. Doing so “simply exports the issue elsewhere — including the imperiled tallgrass prairie ecosystem — with unknown ecological effects,” they wrote, noting that there are now about 23,500 wild horses on private lands in Oklahoma, five times more than the number on open range in Wyoming.

Additionally, the paper contends that wild horses have a comparatively large impact on the range, as they consume more forage and water than ruminants such as cattle, per capita.

The scientists credit the BLM for basing recent management on science, including better population estimates of wild horses and deploying measures to keep them from reproducing. But there are too many animals on the range for this approach to work.

“Although the BLM has admirably increased fertility control research and application, if they are unable to also remove tens of thousands of equids, this process is doomed to be a Sisyphean task,” the researchers wrote.

The federal Wild and Free-Roaming Horses and Burros Act of 1971 essentially calls for wild horses to freely roam like wild animals, but they are treated differently from wild animals because the act prohibits hunting. At the same time, the BLM’s practice of gathering and removing wild horses from the range “more closely resemble livestock operations than wildlife management, whereas adoption programs, sales restrictions and the abolition of slaughter have resulted in feral equids effectively serving as society’s pets,” the paper says.

Choosing one of the labels — wild, livestock or pets — offers the best hope for the federal government to succeed in wild horse management, the scientists wrote.

“As a wild species that lacks sufficient predation to keep most populations in check, a hunting or culling program, like those for other wild ungulates, could slow their population growth,” the paper says. “As livestock, gathers and removals that lead to sale or slaughter would limit growth and give the animals the monetary value they currently lack. As pets, simultaneously conducting large-scale removals and administering fertility control, including permanent sterilization (and potentially euthanasia), could reduce population sizes and slow growth.”

The researchers’ conclusion?

“The current state of feral horse and burro management in the United States is unsustainable and will continue to be a painful resource sink without fundamental changes to the law. We recommend that the U.S. federal government should officially declare the status of feral equids as either wild, livestock or pets and should provide the BLM and (U.S. Forest Service) the legal latitude and funding to develop and implement respective management options.”

The research team from SLAC, Stanford and other institutions started with what is now a fairly standard technique: They zapped a mixture of ferricyanide and water with an ultraviolet laser and bright X-rays generated by the Linac Coherent Light Source (LCLS) X-ray free-electron laser. The ultraviolet light kicked the molecule into an excited state while the X-rays probed the sample’s atoms, revealing features of ferricyanide’s atomic and electronic structure and motion.

What was different this time is how the researchers extracted information from the X-ray data. Instead of studying only one spectroscopic region, known as the Kβ main emission line, the team captured and analyzed a second emission region, called valence-to-core, which has been significantly more challenging to measure on ultrafast timescales. Combining information from both regions enabled the team to obtain a detailed picture of the ferricyanide molecule as it evolved into a key transitional state.

The team showed that ferricyanide enters an intermediate, excited state for about 0.3 picoseconds — or less than a trillionth of a second — after being hit with a UV laser. The valence-to-core readings then revealed that following this short-lived, excited period, ferricyanide loses one of its molecular cyanide “arms,” called a ligand. Ferricyanide then either fills this missing joint with the same carbon-based ligand or, less likely, a water molecule.

“This ligand exchange is a basic chemical reaction that was thought to occur in ferricyanide, but there was no direct experimental evidence of the individual steps in this process,” SLAC scientist and first author Marco Reinhard said. “With only a Kβ main emission line analysis approach, we wouldn’t really be able to see what the molecule looks like when it is changing from one state to the next; we’d only obtain a clear picture of the beginning of the process.”

“You want to be able to replicate what nature does to improve technology and increase our foundational scientific knowledge,” SLAC senior scientist Dimosthenis Sokaras said. “And in order to better replicate natural processes, you have to know all of the steps, from the most obvious to those that happen in the dark, so to speak.”

In the future, the research team wants to study more complex molecules, such as hemeproteins, which transport and store oxygen in red blood cells — but which can be tricky to study because scientists do not understand all the intermediate steps of their reactions, Sokaras said.

The research team refined their X-ray spectroscopy technique at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) and the LCLS over many years, and then combined all this expertise at the LCLS’s X-ray Correlation Spectroscopy (XCS) instrument to capture the molecular structural changes of ferricyanide. The team published their results today in Nature Communications.

“We leveraged both SSRL and LCLS to complete the experiment. We couldn’t have finished developing our method without access to both facilities and our longstanding collaboration together,” said Roberto Alonso-Mori, SLAC lead scientist. “For years, we have been developing these methods at these two X-ray sources, and now we plan to use them to uncover previously inaccessible secrets of chemical reactions.”

240 study participants viewed an interactive Monet Water Lily art exhibition from Google Arts and Culture. By filling out a questionnaire, they provided information about their state of mind, how much pleasure they felt when looking at the pictures, and how meaningful they considered the experience to be. The results showed significant improvements in mood and anxiety after just a few minutes of viewing.

“Online art viewing is an untapped source of support for well-being that can be consumed as bite-sized bits of meaning-making and pleasure,” says MacKenzie Trupp, first author from the University of Vienna.

The study also found that some participants were more receptive to art than others and were able to benefit more. This advantage could be predicted using a metric called “aesthetic responsiveness.”

“Aesthetic responsiveness describes how people react to diverse aesthetic stimuli, like art and nature. The results showed that individuals with high levels of art and aesthetic responsiveness benefit more from online art viewing due to having more pleasurable and meaningful art experiences,” explains Edward A. Vessel of MPIEA, developer of the Aesthetic Responsiveness Assessment (AReA).

The findings of this study are particularly interesting for people who are unable to visit museums in person, such as those with health problems. Furthermore, the results suggest that interactive art exhibitions and similar online experiences should be designed with an awareness of individual differences in aesthetic responsiveness. The study thus expands insight into the benefits and limitations of art in digital media and points the way for increasing the wellness potential of online art.

“This technology could be useful for a wide range of applications,” said research team member Aurora Maccarone, a Royal Academy of Engineering research fellow from Heriot-Watt University in the United Kingdom. “For example, it could be used to inspect underwater installations, such as underwater wind farm cables and the submerged structure of the turbines. Underwater lidar can also be used for monitoring or surveying submerged archaeology sites and for security and defense applications.”

Obtaining 3D images through ocean water can be challenging because it is light-limited, and any particles in the water will scatter light and distort the image. However, single-photon detection, which is a quantum-based technique, allows very high penetration and works even in low-light conditions.

In the Optica Publishing Group journal Optics Express, researchers from Heriot-Watt University and the University of Edinburgh describe experiments in which an entire single-photon lidar system was submerged in a large water tank. The new demonstrations bring the technology closer to practical applications compared to the research team’s earlier experiments with underwater single-photon detection, which were performed in carefully controlled laboratory conditions with the optical setup placed outside the water tank and data analysis performed offline. They also implemented new hardware and software developments that allow the 3D images acquired by the system to be reconstructed in real time.

“This work aims to make quantum detection technologies available for underwater applications, which means that we will be able to image the scene of interest in very low light conditions,” said Maccarone. “This will impact the use of offshore cable and energy installations, which are used by everyone. This technology could also allow monitoring without the presence of humans, which would mean less pollution and a less invasive presence in the marine environment.”

Faster low-light detection

Lidar systems create images by measuring how long it takes laser light to be reflected from objects in the scene and travel back to the system’s receiver, known as the “time of flight.” In the new work, the researchers sought to develop a way to acquire 3D images of targets that are obscured by turbid water and thus not visible to conventional lidar imaging systems.

They designed a lidar system that uses a green pulsed laser source to illuminate the scene of interest. The reflected pulsed illumination is detected by an array of single-photon detectors, which allows ultrafast low light detection and greatly reduces measurement time in photon-starved environments such as highly attenuating water.

“By taking time-of-flight measurements with picosecond timing resolution, we can routinely resolve millimeter details of the targets in the scene,” said Maccarone. “Our approach also allows us to distinguish the photons reflected by the target from those reflected by particles in the water, making it particularly suitable to performing 3D imaging in highly turbid waters where optical scattering can ruin image contrast and resolution.”

The fact that this approach requires thousands of single-photon detectors, all producing many hundreds of events per second, makes it extremely challenging to retrieve and process the data necessary to reconstruct the 3D image in a short time, especially for real-time applications. To solve this problem, the researchers developed algorithms specifically for imaging in highly scattering conditions and applied them in conjunction with widely available graphics processing unit (GPU) hardware.

The new technique builds on some important technological advances. “Heriot-Watt University has a long track record in single-photon detection techniques and image processing of single-photon data, which allowed us to demonstrate advanced single?photon imaging in extremely challenging conditions,” said Maccarone. “The University of Edinburgh has achieved fundamental advances in the design and fabrication of single-photon avalanche diode detector arrays, which allowed us to build compact and robust imaging systems based on quantum detection technologies.”

Underwater testing

After optimizing the optical setup on a laboratory optical bench, the researchers connected the lidar system to a GPU to achieve real-time processing of the data while also implementing a number of image processing approaches for three-dimensional imaging. Once the system was working properly, they moved it to a tank that was 4 meters long, 3 meters wide, and 2 meters deep.

With the system submerged in the water, the researchers added a scattering agent in a controlled manner to make the water more turbid. Experiments at three different turbidity levels demonstrated successful imaging in controlled highly scattering scenarios at distances of 3 meters.

“Single-photon technologies are rapidly developing, and we have demonstrated very promising results in underwater environments,” said Maccarone. “The approach and image processing algorithms could also be used in a wider range of scenarios for improved vision in free space such as in fog, smoke or other obscurants.”

The researchers are now working to reduce the size of the system so that it could be integrated into an underwater vehicle.Through the UK Quantum Technology Hub Network and InnovateUK, the researchers are partnering with industry to make the technology accessible for a range of underwater applications.