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Extreme earth
Towering Mount Everest is famous for its height, but the lowest point on Earth, Challenger Deep, is deeper than Everest is high. The Cave of Crystals in Mexico contains formations of gypsum that look like giant swords. Not only does Earth contain some extreme land formations such as these, but it's constantly changing. The world's largest desert, the Sahara, was once a swamp, and volcanoes are still building islands. These facts and many more, as well as quizzes, diagrams, and fun information boxes, create a book that will make readers truly appreciate Earth's awesome natural history.
Book
Geyser Inspired Algorithm: A New Geological-inspired Meta-heuristic for Real-parameter and Constrained Engineering Optimization
Over the past years, many efforts have been accomplished to achieve fast and accurate meta-heuristic algorithms to optimize a variety of real-world problems. This study presents a new optimization method based on an unusual geological phenomenon in nature, named Geyser inspired Algorithm (GEA). The mathematical modeling of this geological phenomenon is carried out to have a better understanding of the optimization process. The efficiency and accuracy of GEA are verified using statistical examination and convergence rate comparison on numerous CEC 2005, CEC 2014, CEC 2017, and real-parameter benchmark functions. Moreover, GEA has been applied to several real-parameter engineering optimization problems to evaluate its effectiveness. In addition, to demonstrate the applicability and robustness of GEA, a comprehensive investigation is performed for a fair comparison with other standard optimization methods. The results demonstrate that GEA is noticeably prosperous in reaching the optimal solutions with a high convergence rate in comparison with other well-known nature-inspired algorithms, including ABC, BBO, PSO, and RCGA. Note that the source code of the GEA is publicly available at
https://www.optim-app.com/projects/gea
.
Journal Article
Antibacterial activity of a thermophilic actinobacterium Streptomyces cellulosae SL2-2-R-9 on different growth media
Thermophilic Actinobacteria are known as potential producers of novel antimicrobial compounds. However, the optimum growth medium for antibacterial activity assessment of thermophilic Actinobacteria has rarely been reported. This study demonstrated the effects of nine different microbial growth media on antibacterial activity assessment of a thermophilic actinobacterium from the soil in Cisolok geysers, Sukabumi, West Java (Indonesia). The strain SL2-2-R-9 was identified as Streptomyces cellulosae based on 16S rRNA gene data (100% similarity). The antibacterial activity was examined by the agar plug diffusion method against five bacterial test strains. The result of antibacterial activity screening showed that SL2-2-R-9 grown on ISP 7 agar and Bennett’s gellan gum inhibited the growth of Bacillus subtilis, Staphylococcus aureus , and Kocuria rhizophila . Strain grown on ISP 3 gellan gum inhibited the growth of B. subtilis and S. aureus , while on 301 agar and TSA, inhibited only K. rhizophila . Strain grown on ISP 6 agar and modified Bennett’s gellan gum, inhibited only S. aureus. Strain grown on ISP 3 agar and SFM agar showed no inhibition zone against all tested bacteria. There was no inhibition observed against Gram-negative bacteria when the strain was grown on all media.
Journal Article
Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits
The ca. 3.48 Ga Dresser Formation, Pilbara Craton, Western Australia, is well known for hosting some of Earth’s earliest convincing evidence of life (stromatolites, fractionated sulfur/carbon isotopes, microfossils) within a dynamic, low-eruptive volcanic caldera affected by voluminous hydrothermal fluid circulation. However, missing from the caldera model were surface manifestations of the volcanic-hydrothermal system (hot springs, geysers) and their unequivocal link with life. Here we present new discoveries of hot spring deposits including geyserite, sinter terracettes and mineralized remnants of hot spring pools/vents, all of which preserve a suite of microbial biosignatures indicative of the earliest life on land. These include stromatolites, newly observed microbial palisade fabric and gas bubbles preserved in inferred mineralized, exopolymeric substance. These findings extend the known geological record of inhabited terrestrial hot springs on Earth by ∼3 billion years and offer an analogue in the search for potential fossil life in ancient Martian hot springs.
Some of the earliest life on Earth flourished in terrestrial hot springs. Here, the authors present evidence for ca. 3.5 Ga hot spring deposits from the Dresser Formation, Pilbara Craton, Australia, that host some of the earliest known life in the form of stromatolites and other microbial biosignatures.
Journal Article
Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile
The Mars rover Spirit encountered outcrops and regolith composed of opaline silica (amorphous SiO
2
·
n
H
2
O) in an ancient volcanic hydrothermal setting in Gusev crater. An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was suggested previously. However, the potential significance of the characteristic nodular and mm-scale digitate opaline silica structures was not recognized. Here we report remarkably similar features within active hot spring/geyser discharge channels at El Tatio in northern Chile, where halite-encrusted silica yields infrared spectra that are the best match yet to spectra from Spirit. Furthermore, we show that the nodular and digitate silica structures at El Tatio that most closely resemble those on Mars include complex sedimentary structures produced by a combination of biotic and abiotic processes. Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an
a priori
definition of potential biosignatures.
Hydrothermal deposits on Mars may provide the best opportunity to find Martian biosignatures. Ruff and Farmer report that silica structures created by biotic and abiotic process in hot springs at El Tatio, Chile resemble those found in Gusev crater, thus making it an ideal location for future missions.
Journal Article
Fluid flow of CO2-driven geyser activity as inferred from tilt and self-potential observations of the Kibedani Geyser Japan
We conducted multi-parameter, multi-site observations at the Kibedani Geyser, Japan, where cold spring-water eruptions (20 °C) are driven by underground CO
2
pressure. Observations included video, temperature, self-potential (SP), ground tilt, and acoustic measurements. The geyser exhibits a 38-min cycle, consisting of 32 min between eruptions followed by 6 min of eruption. All data revealed changes corresponding to this cycle. Modeling of tilt data indicate that an inclined crack-shaped cavity pressure source expands between eruptions and contracts during eruption, with post-eruption re-expansion beginning ~ 2.5 min after eruption, when ground tremor has ceased. This cavity is interpreted as a bubble trap where CO
2
gas, separated from ascending spring-water, accumulates prior to eruption. SP data modeling suggests that the current source responsible for SP generation, represented by a point and crack-shaped model, is located near this cavity. The correlation between the pressure source and the SP current source suggests that groundwater inflow occurs into the pressure source. Our findings suggest that CO
2
accumulates in the cavity, uplifting water during an eruption and driving groundwater inflow into the cavity. This study highlights the effectiveness of combining tilt and SP methods for analyzing fluid-driven phenomena, providing insights into geyser activity and analogous processes such as volcanic phreatic eruptions. We anticipate that our approach, when applied not only to CO
2
-driven geysers but also to hydrothermal-driven geysers, will contribute to the elucidation of mechanisms underlying phreatic eruptions.
Journal Article
Snow Suppresses Seismic Signals From Steamboat Geyser
Geyser and volcano monitoring suffer from temporal, geographic, and instrumental biases. We present a recording bias identified through multiyear monitoring of Steamboat Geyser in Yellowstone National Park, USA. Eruptions of Steamboat are the tallest of any geyser in the world and they produce broadband signals at two nearby stations in the Yellowstone National Park Seismograph Network. In winter, we observe lower eruption signal amplitudes at these seismometers. Instead of a source effect, we find that environmental conditions affect the recorded signals. Lower amplitudes for 23–45 Hz frequencies are correlated with greater snow depths at the station 340 m away from Steamboat, and we calculate an energy attenuation coefficient of 0.21 ± 0.01 dB per cm of snow. More long‐term monitoring is needed at geysers to track changes over time and identify recording biases that may be missed during short, sporadic studies. Plain Language Summary What we learn about geysers and volcanoes depends on when, where, and how we are able to monitor them. Here we present a case study of how seasonal changes affect data recorded on a seismometer, which is an instrument that measures ground motion. The world's tallest geyser, Steamboat Geyser in Yellowstone National Park, has intense eruptions that eject a mixture of water and steam. The eruptions are powerful enough to cause tiny ground motions from sound waves that begin in the air and then transfer into the ground. In the winter, we see smaller ground motions at two nearby seismometers. This might imply that Steamboat's eruptions are weaker in the winter; however, winter in Yellowstone comes with snow, and snow is good at absorbing sound wave energy. We find that smaller ground motions occur when snow depths are greater, and that the strength of ground motions should not be used to directly compare eruption intensity. Few geysers around the world are monitored with scientific equipment for long periods of time. Our result highlights the need for more of this type of monitoring so that we can identify biases that may be missed during shorter investigations. Key Points Seismic signals from Steamboat Geyser eruptions contain ground‐coupled airwaves at distances up to 2.2 km Snow dampens airwave arrivals leading to lower apparent signal amplitudes in winter Interpretation of eruption signals at both geysers and volcanoes should take changing environmental factors into account
Journal Article