These Puerto Rican tsunami deposits, along with similar age deposits at other islands in the Caribbean, suggest that the tsunami would have been triggered by a massive magnitude 8.7 or larger earthquake, said Bruce Jaffe of the U.S. Geological Survey.

The deposits could be very important for understanding seismic risk in the region, since written records of tsunamis in the Caribbean extend back only 500 years, and the evidence for magnitude 8.0 or larger earthquakes on the Puerto Rico Trench is sparse.

Previous research has uncovered Caribbean tsunami deposits along the northern segment of the Lesser Antilles arc in Anegada, St-Thomas (U.S. Virgin Islands), Anguilla, and Scrub Island (British Virgin Islands).

The researchers estimate that these deposits, ranging in age from 1200 to 1500 years before the present, could be the result of a tsunami generated by a magnitude 8.0 to 9.0 earthquake that ruptured at least 300 kilometers.

If the Puerto Rico pond deposits came from the same event, “it could be a large length of fault that ruptured — 400 kilometers, roughly,” said Jaffe.

Earthquake modeling for the Lesser Antilles arc deposits suggested a magnitude 8.7 earthquake. Models that include the newly discovered Puerto Rico deposits indicate that the tsunami-triggering earthquake “would have to be quite a bit larger,” he added.

The tsunami itself may have impacted both the Caribbean and Atlantic coasts of Puerto Rico.

Jaffe and colleagues scouted dozens of locations in Puerto Rico “looking for the right setting for a possible tsunami deposit to form and for it to be preserved,” he said. In a coastal mangrove pond at East Bajura near Isabela in Northwest Puerto Rico, they found a likely candidate close to the shore and flanked by ancient dunes that could protect the pond from swells.

In sediment cores taken from the pond, the researchers found a thin sand sheet about a half a meter deep that blanketed the whole pond. The deposit bears several signatures of a tsunami event, including an eroded basal layer and a unique gradation of sediment particles.

Sediment swept up in the high-speed flow of a tsunami remains suspended in the water, “because the turbulent eddies are strong enough to mix the sediment from the [sea]bed all the way up through the water column,” explained Jaffe, who has analyzed deposits in the wake of six major tsunamis worldwide. “It creates a very distinctive grading of sediment in the core.”

The researchers are examining large cores taken from the pond with CT scans and X-ray fluorescence, among other tools, looking for fine details such as the direction of grass roots and the mineral composition of sediment grains to further constrain the timing and the source of the tsunami.

One of the researchers, Matthew Baez, a graduate student working with Jaffe and Alberto López-Venegas of the University of Puerto Rico, Mayagüez is looking for similar ponds along the north coast of Puerto Rico that could corroborate the findings from the East Bajura pond. And Jaffe said there are plans to take a deeper core from the current pond to look for evidence of earlier tsunamis.

Study co-author López-Venegas said there has been a lack of paleo-tsunami research on major earthquakes affecting Puerto Rico’s northern coast. The 2 May 1787 earthquake that most likely occurred offshore the northern coast of Puerto Rico, likely centered on the Main Ridge within Puerto Rico Trench, is one of the most significant seismic events to affect that part of the island.

“The bottom line is, we still have a lot of work to do as we do not have a good grasp of which events have occurred along the Puerto Rico Trench, and much more paleo-tsunami work is required to understand better what has occurred in the past and what may happen in the future,” López-Venegas said.

“Ribonucleic acid or RNA is one type of genetic material that is present inside all living cells. It is mostly known to act as a messenger carrying instructions encoded in the DNA for the synthesis of proteins,” said co-corresponding author, Dr. Aleksandar Milosavljevic, professor and Henry and Emma Meyer Chair in Molecular Genetics at Baylor. He also is the director of the Graduate Program in Quantitative & Computational Biosciences and a member of the Dan L Duncan Comprehensive Cancer Center at Baylor. The Milosavljevic Lab is the host of the exRNA Atlas, the data management and resource repository of the Extracellular RNA Communication Consortium, an NIH Common Fund project exploring the biology of exRNA.

In recent years research has shown that RNA not only exists inside cells, but also is exported from cells as extracellular RNA and plays a role in cell-to-cell communication.

“ExRNAs exist in bodily fluids outside of cells where they can associate with a variety of carriers including RNA binding proteins (RBPs), but the cargo and distribution of RBPs across biofluids is largely unknown,” said coauthor Robert Fullem, a graduate student in the Milosavljevic lab. “Our goal in this study was to fill that gap. This major gap in knowledge limited our understanding of the role of RBPs as carriers of exRNA in human bodily fluids. Our findings open a new road toward understanding exRNA biology and provide new opportunities for the development of exRBP/exRNA liquid biopsy biomarkers.”

The researchers applied computational analyses to identify exRBPs in plasma, serum, saliva, urine and cerebrospinal fluid. The computational predictions were validated experimentally at about 80% in both plasma and cell cultures in the lab, suggesting high specificity for the computational method.

“With this information, we developed a map of candidate exRBPs and their exRNA cargo in bodily fluids expanding the landscape of potential biomarkers that can now be studied in liquid biopsies and used to track normal and disease processes,” Milosavljevic said. “We present this map as a resource available at no cost to the scientific community.”

Other contributors to this work include co-first authors Emily L. LaPlante and Alessandra Stürchler, David Chen, Anne C. Starner, Emmanuel Esquivel, Eric Alsop, Andrew R. Jackson, Ionita Ghiran, Getulio Pereira, Joel Rozowsky, Justin Chang, Mark Gerstein, Roger P. Alexander, Matthew E. Roth, Jeffrey Franklin, Robert Coffey, Robert L. Raffai, Isabelle M. Mansuy, Stavros Stavrakis, Andrew deMello, Louise C. Laurent, Yi-Ting Wang, Chia-Feng Tsai, Tao Liu, Jennifer Jones, Kendall Van Keuren-Jensen and Eric Van Nostrand. 

This publication was supported in part by the NIH Common Fund (1UG3TR002881-01, 1U54DA036134-01,1U54DA049098-01, 1U54DA049098-01S1, 1UH3TR002881, OT2OD030547-01S1 and 5UG3TR002881-02). Further support was provided by CPRIT Scholar in Cancer Research grants RR200040, 4UH3CA241703-03, and a Swiss National Center of Competence (NCCR) in Research RNA & Disease grant.

Biocrusts play a crucial role in maintaining soil health and ecosystem sustainability, but they are currently under assault. Human activities including agriculture, urbanization, and off-road vehicle use can lead to the degradation of biocrusts, which have long-term consequences for these fragile environments. Climate change is also placing stress on biocrusts, which struggle to adapt to sunlight and searing heat in arid landscapes like the Sonoran Desert.

Now, Ferran Garcia-Pichel and his student at Arizona State University propose an innovative approach to restoring healthy biocrusts. The idea is to use new and existing solar energy farms as nurseries for generating fresh biocrust.

Safely shielded from the sun beneath arrays of solar panels, like beachgoers under an umbrella, the biocrusts are sheltered from excessive heat and can flourish and develop. Ultimately, the newly generated biocrusts can then be used to replenish arid lands where such soils have been damaged or destroyed.

Help for desert soil

In a proof-of-concept study, ASU researchers adapted a suburban solar farm in the lower Sonoran Desert as an experimental breeding ground for biocrust. During the three-year study, photovoltaic panels promoted biocrust formation, doubling biocrust biomass and tripling biocrust cover compared with open areas with similar soil characteristics.

When biocrusts were harvested, natural recovery was moderate, taking around 6-8 years to fully recuperate without intervention. However, when harvested areas were re-inoculated, the recovery was much faster, with biocrust cover reaching near-original levels within one year.

The researchers emphasize that the use of similar, but larger, solar farms could provide a low-cost, low-impact, and high-capacity method to regenerate biocrusts and expand soil restoration approaches to regional scales. They have dubbed their pioneering approach “crustivoltaics.”

The study estimates that use of the three largest solar farms in Maricopa County, Arizona as biocrust nurseries could empower a small-scale enterprise to rejuvenate all idle agricultural lands within the county, spanning more than 70,000 hectares, in under five years. Among many environmental benefits, this restoration effort has the potential to significantly decrease airborne dust presently impacting the Phoenix Metropolitan region.

“This technology can be a game changer for arid soil restoration,” Garcia-Pichel says. “For the first time reaching regional scales at our fingertips, and we could not be more excited. To boot, crustivoltaics represents a win-win approach for conservation of arid lands and for the energy industry alike.”

Garcia-Pichel is a Regents’ Professor in the School of Life Science and the founding director of the Biodesign Center for Fundamental & Applied Microbiomics. The center amalgamates researchers that study assemblages of microbes (or microbiomes) acting in unison in various settings, from humans to animals and plants, to oceans and deserts. Garcia-Pichel’s lab has specialized in the study and applications of desert soil microbiomes.

The group’s findings appear in the current issue of the journal Nature Sustainability, in a publication co-lead by graduate student Ana “Meches” Heredia-Velásquez, and former graduate student Dr. Ana Giraldo-Silva, now a professor at the Public University of Navarre in Spain. A separate briefing of this contribution appears concurrently in Nature.

Living matrix

Biocrusts are complex ecosystems researchers have only recently begun to explore. Among their many housekeeping functions, they act to stabilize soil by binding soil particles together, minimizing the loss of topsoil caused by wind and water. They contribute to nutrient cycling by fixing atmospheric nitrogen, a process where nitrogen gas is converted into ammonia, making it available to plants. Cyanobacteria, which are present in biocrusts, are the primary organisms responsible for this process.

Photosynthetic activities within biocrusts play a role in carbon storage by fixing atmospheric carbon dioxide. This process can help mitigate some of the effects of climate change by removing carbon dioxide from the atmosphere. Biocrusts also increase the soil’s water-retaining capacity, allowing more water to infiltrate the soil and reducing runoff. This helps to improve water availability for plants and other organisms in arid ecosystems.

Finally, biocrusts support a diverse community of microorganisms that contribute to overall ecosystem biodiversity and resilience.

Drylands, which make up approximately 41% of the Earth’s continental area, are experiencing severe degradation due to human activities and climate change. The communities of microorganisms on soil surfaces are vital to protect and fertilize these soils and are essential for dryland sustainability. However, current biocrust restoration methods involve high effort and low capacity, limiting their application to small areas. Existing methods have struggled to replenish more than a few hundred square meters of land.

Solar solutions

The research suggests that solar farms serve as biocrust hotspots, as the elevated photovoltaic panels create a greenhouse-like microclimate promoting biocrust development. Although crustivoltaics is a slower and weather-dependent method compared to greenhouse-sized biocrust nurseries, it has many advantages. The technique requires fewer resources, minimal management, and no upfront investment. Indeed, the use of crustivoltaics is 10,000 times more cost-effective than current methods, according to the research findings.

The next steps will involve implementing crustivoltaics at regional scales through the cooperation of scientists, collaborative agencies, land users and managers. Use of the technique can provide incentives to solar farm operators, including reduced dust formation on solar panels and increased revenue from carbon credits.

The crustivoltaic approach has the potential to offer a dual-use solution for both solar power generation and biocrust restoration on a large scale, while also providing socioeconomic benefits. This method could play a significant role in the restoration and sustainability of dryland ecosystems.

The results of the joint project, which was funded by the German Federal Ministry of Education and Research (BMBF), are published in the article ‘Stabilization of mineral-associated organic carbon in Pleistocene permafrost’ in the journal Nature Communications.

The Arctic is warming dramatically fast compared to other parts of the world. Much of it is covered by permafrost and contains large amounts of carbon, almost twice as much as the atmosphere. This carbon comes from plants that have grown over thousands of years, decomposed in the soil and then become ‘frozen’. Due to strongly rising temperatures in the Arctic, this gigantic freezer is thawing fast. The old carbon stored in it can now be degraded by microorganisms, releasing carbon dioxide and methane into the atmosphere. These greenhouse gases accelerate global warming. The warmer it gets, the more greenhouse gases are in turn released from the permafrost, causing temperatures to rise further and frozen soils and sediments to thaw even faster. “There is a feedback of carbon in permafrost with climate, the strength of which depends largely on those factors that influence microbial degradation,” said Janet Rethemeyer.

In the joint research project, scientists from the Institute of Zoology at the University of Cologne, the University of Tübingen, the Technical University of Munich and the Alfred-Wegener-Institute in Potsdam studied long permafrost cores from the Siberian Arctic. The cores come from very ice-rich, fine-grained sediments — similar to loess in our latitudes — that were deposited in large areas of Siberia and Alaska during the last ice age. The cores, up to 12 metres long, comprise sediments deposited over a period of up to 55,000 years.

The analyses of the permafrost cores show that a significant part (25-35 %) of the carbon is associated with the mineral particles and thus more difficult to access for microorganisms. “Predictions of interactions between thawing permafrost and climate are very complicated because the microbial degradability of the organic material in the sediments has varied greatly over the last 55,000 years. This is due to the different climatic conditions during this long period of deposition,” Janet Rethemeyer explained. Warmer and wetter conditions resulted in poorer binding of carbon to the mineral particles, while a colder and drier climate led to stronger binding, primarily to iron oxides. Stronger binding to iron oxides means that the decomposition rates of old plant material are lower, as Professor Dr. Michael Bonkowski from the Institute of Zoology, Department of Terrestrial Ecology at the University of Cologne has shown in laboratory experiments.

“These new findings can make a significant contribution to making computer models for forecasting greenhouse gas emissions from thawing permafrost more reliable,” said Jannik Martens, who is currently conducting research at Columbia University in New York.

A new study led by Dr. Natalie Johnson, associate professor in the Texas A&M University School of Public Health’s Department of Environmental and Occupational Health, shows that exposure to ultrafine particles (UFPs) during pregnancy enhances respiratory viral infection risk. The results of the study were published recently in Particle and Fibre Toxicology.

“We know that air pollution affects the pulmonary immune system, making individuals more susceptible to viral infections,” Johnson said. “We also know pregnant women are already at increased risk for severe flu. Surprisingly, studies have not interrogated the combined effects of pregnancy, air pollution and influenza. Our findings demonstrate the need to further study these interactions in order to prevent short and perhaps long-term impacts on maternal health.”

In the study, Johnson and her co-authors point out that there are several physiological characteristics that explain maternal susceptibility to viral infection. Among those are increased cardiac output and decreased tidal volume — the amount of air that moves in or out of the lungs with each respiratory cycle — as well as immunological changes such as selective modulation of immune cell subsets to protect the developing fetus.

The research team also highlights that vaccination compliance during pregnancy is generally below 50 percent, despite vaccination against influenza being safe and effective, leading to increased risk for developing respiratory infection.

As a result, air pollution, which is a worldwide environmental health issue, is responsible for one in nine deaths with an annual premature mortality of more than 7 million. A mixture of gases and tiny airborne particulate matter, which is categorized as UFPs, are critical to recognize and identify, especially to protect vulnerable populations.

The research team says these findings support future clinical and regulatory interventions for protecting pregnant women and controlling UFPs. According to the researchers, it is imperative that pregnant women in urban cities, where influenza and UFPs are more prevalent, are provided vaccinations and preventive measures limiting UFP exposure to protect maternal health.

“Air pollution is a pervasive environmental health issue,” Johnson said. “Strategies to protect the most vulnerable, like pregnant women, are of high priority to decrease adverse health effects.”

Additional authors include Nicholas L. Drury, Texas A&M Department of Environmental and Occupational Health and Texas A&M Department of Nutrition; Toriq Mustapha, Texas A&M Department of Environmental and Occupational Health; Ross A. Shore, Texas A&M Department of Environmental and Occupational Health, Jiayun Zhao, Texas A&M Department of Chemistry; Gus A. Wright, Texas A&M Department of Veterinary Pathobiology; Aline Rodrigues Hoffmann, University of Florida Department of Comparative, Diagnostic, and Population Medicine; Susanne U. Talcott, Texas A&M Department of Nutrition; Annette Regan, University of San Francisco School of Nursing and Health Professions; Robert M. Tighe, Duke University Department of Medicine; and Renyi Zhang, Texas A&M Department of Chemistry and Texas A&M Department of Atmospheric Sciences.