Explore the vast range of titles available.

Hydrothermally active submarine volcanoes are mineral-rich biological oases contributing significantly to chemical fluxes in the deep sea, yet little is known about the microbial communities inhabiting these systems. Here we investigate the diversity of microbial life in hydrothermal deposits and their metagenomics-inferred physiology in light of the geological history and resulting hydrothermal fluid paths in the subsurface of Brothers submarine volcano north of New Zealand on the southern Kermadec arc. From metagenome-assembled genomes we identified over 90 putative bacterial and archaeal genomic families and nearly 300 previously unknown genera, many potentially endemic to this submarine volcanic environment. While magmatically influenced hydrothermal systems on the volcanic resurgent cones of Brothers volcano harbor communities of thermoacidophiles and diverse members of the superphylum “DPANN,” two distinct communities are associated with the caldera wall, likely shaped by two different types of hydrothermal circulation. The communities whose phylogenetic diversity primarily aligns with that of the cone sites and magmatically influenced hydrothermal systems elsewhere are characterized predominately by anaerobic metabolisms. These populations are probably maintained by fluids with greater magmatic inputs that have interacted with different (deeper) previously altered mineral assemblages. However, proximal (a few meters distant) communities with gene-inferred aerobic, microaerophilic, and anaerobic metabolisms are likely supported by shallower seawater-dominated circulation. Furthermore, mixing of fluids from these two distinct hydrothermal circulation systems may have an underlying imprint on the high microbial phylogenomic diversity. Collectively our results highlight the importance of considering geologic evolution and history of subsurface processes in studying microbial colonization and community dynamics in volcanic environments.

Understanding the origin of Late Jurassic volcanism in southern Patagonia is crucial for unraveling the early Andean orogenic evolution. However, radiometric dating is not connected to stratigraphic analysis along the South Patagonian Andes, which obscures the real duration of the Late Jurassic magmatic activity. In this contribution, we present the results of a volcanic stratigraphy analysis, complemented by structural and petrographic data, on a thick succession of acidic volcanogenic rocks in the Laguna Verde district of southern Chile located along the south shore of General Carrera-Buenos Aires Lake. Through the recognition of igneous stratigraphy, we strategically sampled representative volcanogenic rocks that cover the entire duration of eruptive activity. By doing so, the new U–Pb zircon magmatic ages, combined with a compilation of U–Pb crystallization ages from the South Patagonian Andes, allows us to constrain the volcanic activity in the study area to a period of 8 My (~ 155–146 Ma, V3 stage) and 11 My considering age inherent errors. The field recognition of normal faults and the syn-kinematic emplacement of sub-volcanic bodies, which are inferred to conform to a ring-fault system, along with the presence of a thick succession of ignimbrites, suggest that the syn-extensional volcanic emplacement occurred in a caldera volcanic environment. This setting was responsible for the short-lived, voluminous eruptions. Furthermore, the high Th/U zircon ratios identified for the ~ 155–150 Ma period indicate the climax of extensional tectonics. The integration of these data supports the hypothesis that retreating-mode subduction played a major role in producing ignimbrite flare-ups. Graphical abstract

The 2021 eruption of the Tajogaite volcano (La Palma, Canary Islands) provided a unique opportunity to investigate the early post-eruptive magnetic structure of a newly formed volcanic edifice. Understanding these structures is essential for improving hazard assessment and risk mitigation strategies. In this study, we present the first high-resolution, drone-based aeromagnetic dataset over the Tajogaite volcano, aimed at clarifying its still-uncertain geodynamic framework at shallow depths. We describe the data acquisition and processing workflows for surveying volcanic terrains, providing insights into the challenges encountered and the methodologies applied. The magnetic dataset was analyzed and used to construct a 3D magnetic susceptibility model of the volcanic edifice and its surroundings. Our results revealed very low magnetic susceptibility values at very shallow depths (~50 m below the surface) over the main volcanic edifice, suggesting the presence of a likely vertical, dyke-like structure feeding the eruption. These findings indicate that these materials remain above their Curie temperature around two years after the eruption. Moreover, the magnetic anomalies display patterns that correlate with the previously inferred two-fault systems, which likely played a critical role in channelling magma toward the eruptive vents. An elongated zone of slightly low magnetic susceptibility was identified following the NE-SW Mazo fault orientation, extending toward the eruptive fissure. This feature was associated with a single, fault-controlled magma pathway that remained at high temperatures at the time of the survey, in agreement with studies in other volcanic environments. This study highlights the value of aeromagnetic surveys, particularly those conducted with drones, as effective tools for advancing our understanding of young and dynamic volcanic systems, especially regarding their shallow structures.

Antimicrobial resistance (AR) is recognized as one of the greatest threats to public health and in global concern. Consequently, the increased morbidity and mortality, which are associated with multidrug resistance bacteria, urgently require the discovery of novel and more efficient drugs. Conversely, cancer is a growing complex human disease that demands new drugs with no or fewer side effects. Most of the drugs currently used in the health care systems were of Streptomyces origin or their synthetic forms. Natural product researches from Streptomyces have been genuinely spectacular over the recent years from extreme environments. It is because of technical advances in isolation, fermentation, spectroscopy, and genomic studies which led to the efficient recovering of Streptomyces and their new chemical compounds with distinct activities. Expanding the use of the last line of antibiotics and demand for new drugs will continue to play an essential role for the potent Streptomyces from previously unexplored environmental sources. In this context, deep-sea, desert, cryo, and volcanic environments have proven to be a unique habitat of more extreme, and of their adaptation to extreme living, environments attribute to novel antibiotics. Extreme Streptomyces have been an excellent source of a new class of compounds which include alkaloids, angucycline, macrolide, and peptides. This review covers novel drug leads with antibacterial and cytotoxic activities isolated from deep-sea, desert, cryo, and volcanic environment Streptomyces from 2009 to 2019. The structure and chemical classes of the compounds, their relevant bioactivities, and the sources of organisms are presented.

Forecasting of volcanic eruptions is still inadequate, despite technological advances in volcano monitoring. Improved forecasting requires a deeper understanding of when unrest will lead to an actual eruption. Shallow, long-period seismic events often precede volcanic eruptions and are used in forecasting. They are thought to be generated by resonance in fluid-filled cracks or conduits, indicating the presence of near-surface magmatic fluids. Here we analyse very-high-resolution seismic data from three active volcanoes—Mount Etna in Italy, Turrialba Volcano in Costa Rica and Ubinas Volcano in Peru—measured between 2004 and 2009. We find that seismic resonance is dependent on the wave propagation path and that the sources for the long-period seismic waves are composed of short pulses. We use a numerical model to show that slow-rupture failure in unconsolidated volcanic materials can reproduce all key aspects of these observations. Therefore, contrary to current interpretations, we suggest that short-duration long-period events are not direct indicators of fluid presence and migration, but rather are markers of deformation in the upper volcanic edifice. We suggest that long-period volcano seismicity forms part of the spectrum between slow-slip earthquakes and fast dynamic rupture, as has been observed in non-volcanic environments. Volcanic eruptions are often preceded by long-period seismic events that were thought to be generated by the resonance of cracks filled with magmatic fluid. Analysis and modelling of long-period seismicity at volcanoes in Italy, Costa Rica and Peru shows that it could instead be caused by slow rupture along faults in the upper volcanic edifice.

Active volcanic environments represent extreme habitats with underexplored potential for microbial bioprospecting. This study aimed to characterize pioneer vegetation and associated microbial diversity in the crater of “El Chichonal” volcano, with an emphasis on their potential applications in sustainable agriculture. A physicochemical analysis of the soil was performed, identifying acidic and nutrient-poor conditions. Three pioneer plant species were described: Tibouchina longifolia (dominant) and Poaceae spp. (co-dominant), and Palhinhaea cernua (non-dominant). A total of 311 microorganisms were predominantly bacteria, were isolated from soil, root, stem, and water samples. Bacillus cereus and Priestia megaterium were molecularly identified, and in vitro assays demonstrated their ability to fix nitrogen, produce auxins, and antagonize fungal pathogens ( Alternaria solani , Botrytis cinerea , and Colletotrichum gloeosporioides ). These results suggest that microorganisms adapted to extreme volcanic environments could be promising sources of plant growth-promoting bacteria (PGPB) with application in biological control. Graphical Abstract

Natural radiogenic isotopes (primarily 87Sr/86Sr) from hot springs in the Upper Geyser Basin of the Yellowstone Plateau volcanic field and associated rocks were used to evaluate groundwater flow patterns, water‐rock reactions, and the extent of mixing between various groundwater sources. Thermal waters have very low uranium concentrations and 234U/238U activity ratios near 1.0, which limit their utility as tracers in this reducing setting. Thermal waters have higher Sr concentrations (<22 ng/g) and a wide range of 87Sr/86Sr values that vary both temporally at individual discharge sites and between adjacent springs, indicating that conduits tap different subsurface reservoirs to varying degrees. Sr from local rhyolites have 87Sr/86Sr compositions that bound the range of values observed in groundwater throughout the basin. Non‐boiling springs on the west flank of the basin discharge water with low 87Sr/86Sr consistent with flow through young volcanic rocks exposed at the surface. Boiling springs in the central basin have higher 87Sr/86Sr values reflecting interactions with older, more radiogenic volcanic rocks. Variability in upwelling thermal waters requires mixing with a low 87Sr/86Sr component derived from young lava or glacial sediments, or more likely, from deeper sources of hot groundwater circulating through buried Lava Creek Tuff having intermediate 87Sr/86Sr. Isotope data constrain basin‐wide output of thermal water to 110–140 kg·s−1. Results underscore the utility of radiogenic Sr isotopes as valuable tracers of hydrothermal flow patterns and improve the understanding of temperature‐dependent water‐rock reactions in one of the largest continental hydrothermal systems on Earth. Plain Language Summary Radiogenic isotopes of strontium (87Sr/86Sr) vary widely in rocks and the waters that interact with them. We use 87Sr/86Sr in waters from hot springs in the Upper Geyser Basin of the Yellowstone Plateau volcanic field to help define patterns of groundwater flow through subsurface volcanic rocks. Lava flows and tuffs adjacent to and underlying the basin have different 87Sr/86Sr compositions reflecting different crustal and mantle components incorporated during rhyolite generation. Groundwater interacting with those rocks inherits their 87Sr/86Sr signature, which can then be used to trace subsurface flowpaths. Modern and past hot springs along the basin margin discharge water having low 87Sr/86Sr values that indicate groundwater was restricted to shallow flowpaths through younger volcanic rocks. Hot springs in the central basin have compositions reflecting mixing between groundwater flowing through deeper and older, high‐87Sr/86Sr volcanic rocks and groundwater having lower 87Sr/86Sr values. The low‐87Sr/86Sr component could be derived from shallow sources (young volcanic rocks or glacial sediments) or from more‐deeply buried tuff associated with the most recent collapse of the Yellowstone caldera. The data presented here provide a means of tracing hydrothermal flow patterns in complex volcanic environments and improve the understanding of hydrothermal activity in one of the largest active continental magmatic systems on Earth. Key Points Water from hot springs in the Upper Geyser Basin has 87Sr/86Sr derived from volcanic rocks flanking and underlying the basin Variable 87Sr/86Sr in water from springs in proximity and over time reflect mixing between groundwater in distinct rock reservoirs Reducing conditions along flowpaths yield groundwater with low U concentrations and 234U/238U activities near 1.0

Secondary alteration minerals like clays accompanied by volcanic activity can provide an important information on eruption cycle. Representative volcanic tuffs and seabed sediments were collected from the Dokdo volcanic island in East Sea, South Korea, to interpret eruption cycle based on clay mineral characteristics and other geochemical proxies (sulfur isotope composition, Si/Al, K/Al, among others). Tuffs are mainly composed of volcanic glass and hydrothermally altered phenocrysts. Secondary minerals such as clay mineral species in volcanic tuffs mostly were identified as smectite comprising dioctahedral sheets, based on expanding to 15.8 Å after treatment with 1 M MgCl2 solution, and 060 reflections near at 1.48 Å. Moreover, the results of infrared bands, based on (Al, Al)–OH (904–912 cm−1), (Al, Fe)–OH (865–877 cm−1), (Fe, Mg)–OH (778–798 cm−1) indicate the presence of dioctahedral sheets in clay mineral structure. Partially, occurrence of kaolinite and relatively low pH values and K/Al ratios at the Eolgulbawi tuff support chemical flexibility of clay mineral species. The δ34S value of Dongdo tuff (H2O–S: 15.3‰) is close to water leached sulfate, whereas Seodo tuff II including pyrite and native sulfur (− 5.5‰) shows a value of H2S-bearing volcanic gases. The similarity of chemical compositions between clay fractions and surrounding volcaniclastic rocks suggests that the smectite formed in low-temperature hydrothermal environments, where alkali elements were supplied under reducing conditions. Clay fractions separated from seabed sediments include diatom frustule with higher SiO2/Al2O3 ratios, and clay minerals contain mineral nitrogen originated from organic-rich seafloor sediments. Moreover, the δ34S values of seabed sediments (1.8‰, 8.4‰) indicate that the different origin of clay mineral species between tuffs and seabed sediments. It can be concluded that the alteration types and clay mineral characteristics are similar to the Surtseyan volcano, generally known as shallow-marine phreatomagmatic eruption and deposits. It further suggests that clay minerals sensitive to environmental change will be useful to interpret the volcanic environment characterized by explosive hydrovolcanic activities that occurred at the time of magma in contact with water before erupting into the atmosphere.

Volcanic volatile emissions provide information about volcanic unrest but are difficult to detect with satellites. Volcanic degassing affects plants by elevating local CO2 and H2O concentrations, which may increase photosynthesis. Satellites can detect plant health, or a reaction to photosynthesis, through a Normalized Difference Vegetation Index (NDVI). This can act as a potential proxy for detecting changes in volcanic volatile emissions from space. We tested this method by analyzing 185 Landsat 5 and 8 images of the Tern Lake thermal area (TLTA) in northeast Yellowstone caldera from 1984 to 2022. We compared the NDVI values of the thermal area with those of similar nearby forests that were unaffected by hydrothermal activity to determine how hydrothermal activity impacted the vegetation. From 1984 to 2000, plant health in the TLTA steadily increased relative to the background forests, suggesting that vegetation in the TLTA was fertilized by volcanic CO2 and/or magmatic water. Hydrothermal activity began to stress plants in 2002, and by 2006, large swathes of trees were dying in the hydrothermal area. Throughout most of the 1990s, the least healthy plants were located in the area which became the epicenter of hydrothermal activity in 2000. These findings suggest that plant‐focused measurements are sensitive to minor levels of volcanic unrest which may not be detected by other remote sensing methods, such as infrared temperature measurements. This method could be a safe and effective new tool for detecting changes in volatile emissions in volcanic environments which are dangerous or difficult to access. Plain Language Summary Scientists often measure volatile emissions from volcanoes to understand how the magma underneath the volcano is behaving to anticipate potential volcanic hazards. These emissions are difficult and often hazardous to measure on the ground; therefore, measuring them with satellites would facilitate consistent and safe detection of changes in volcanic activity. It is nearly impossible to directly measure volcanic carbon dioxide and H2O from space, so we need another method. We use plants as a proxy because they use carbon dioxide and water for photosynthesis, so if plants receive these extra gases from the volcano, it should improve plant health. We detected signals of this increased health from 1984 to 2001 in Yellowstone National Park, USA. One area of the forest that was exposed to volcanic gases was healthier than nearly identical, nearby forests growing without the influence of the volcano. This supports the idea that extra volcanic carbon dioxide and water promote tree health. As volcanic activity intensifies, it can harm plants. We detected increases in plant stress caused by increases in soil temperature and sulfur emissions before they were detectable by other types of satellites. Combining these two contrasting effects represents a promising new path for additional monitoring of active volcanoes. Key Points Plant responses to elevated CO2 may be a viable proxy for volcanic CO2 We have detected variations in diffuse volatile emissions in Yellowstone using plant responses Plants responded to changes in volatile emissions several years before hydrothermal activity was previously thought to have started

Slope movements are one of the natural hazards that most affect volcanic islands and often cause alarm to society, as they produce considerable material losses, affect communications and basic community services and, on occasion, involve the loss of human lives. Based on the classification of geotechnical units of the Canary Islands and the characteristic slope movements observed in each of them, the main goal of this article has been to elaborate a classification of movements versus units, as a tool for the management landslides hazards in volcanic environments. The applied methodology was based on the types of slope movements defined by the USGS, and on the research team three decades of experience of the study of geotechnical characterisation and slope instability of volcanic formations. A graphical classification of the possible movements affecting the volcanic geotechnical units has been prepared to make a preliminary estimate of the types of movements that will affect a slope or hillside.