Byrsonima crassifolia seedlings growth on ground basalt rock

Ground basalt rock may represent a labile reservoir of nutrients, providing a low-cost, nutrient-rich substrate for seedling formation and plant growth. The study aimed to evaluate the development of a native plant murici [Byrsonima crassifolia (L.) H.B.K.] seedlings using two different application rates of ground basalt rock with two particles sizes. The experiment was performed in a greenhouse, in which treatments were arranged in a random block design with five replications in a factorial scheme (2 x 5 + 1), with five doses of finely ground basaltic rock (0.42; 1.04; 2.08; 4.17 and 8.33 g kg-1), two grain sizes (G1 Ø < 0.05 and G2 Ø < 0.10 mm mesh), and a treatment with soil without rock powder addition (the control 0.0 g kg-1 of rock powder). The seedlings were cultivated in substrate incubated for 120 days with the ground basaltic rock. Six months after the seedlings were planted variables involving growth and nutrient content variables were evaluated. Grain size affected nutrient availability from finely ground rock (Ca, Mg, Fe, and Zn). The growth of murici seedlings linear increase with ground basaltic rock application rates, with better results when a 0.05 mm grain size was used.

Glass and Glass-ceramics based on Weathered Basaltic Rock for Radiation Shielding Applications

Different batches of weathered basalt ranging from 100 to 50%, in combination with by-pass cement dust, were used to prepare the glass compositions. Different techniques used, such as differential thermal analysis, X-ray diffraction, density, FTIR, the mass attenuation coefficients, appropriate atomic number (Zeff), and effective electron density (Neff), were examined for the prepared glass and glass-ceramics samples at different photon energies.. In the present study, it was revealed that as the molar volume decreases, the density increases. The experimental and theoretical effects of the mass attenuation component were mostly consistent at different energies. Results revealed that glass samples (WB100) having a higher percentage of basaltic rocks present higher radiation protection than those with a lower rate (WB50). In addition, glass-ceramics displayed enhanced radiation and gamma rays protection than glass. Therefore, we recommend using glass ceramics containing 100% Basalt as a protective shield against rays with less thickness and higher protection.

Basaltic Outcrops as Centers of Diversity for Xerothermic Plants in the Sudetes Mountains (Central Europe)

Rock outcrops have promoted a high level of species diversity and provided a stable microclimate for long time periods. The present study is devoted to plant diversity of natural Quaternary outcrops of basaltic rocks. Chorological and ecological investigations were carried out at 35 such outcrops, located within five physiogeographic units of the Sudetes Mountains. The focus was on 120 xerothermic taxa of vascular plants: 62 strictly xerothermic (steppe) taxa of the Festuco valesiacae-Brometea erecti class, and 58 thermophilous taxa representing classes Trifolio medii-Geranietea sanguinei and Quercetea pubescentis. Limited geographical ranges of these plants are manifested by variable frequency of their occurrence. Species distribution is determined by natural factors, like surface area of the outcrop, the type of basaltic rock and the type of plant communities developed. Basaltic outcrops in the Sudetes meet the criterion of habitat islands (inselbergs), serve as regional centers of vascular flora, and are refugia for marginal populations of relict species.

Analysis of the influence of partial replacement of mineral aggregate by basaltic rock dust on the production of industrialized adhesive mortar

The production of adhesive mortar uses large proportions of sand, causing undesirable environmental impact as this is a finite resource. In recent years, the insertion of civil construction waste in cement matrixes has intensified with the objective of replacing sand in the mortar manufacturing process. Therefore, in this study, the proportions of 5%, 10%, 15% substitution of the mineral aggregate by basalt dust waste in the production of industrialized adhesive mortar were adopted. The reference mixture of 1:3 (cement: sand) was adopted and the water/dry material ratio was set at 0.20. The adhesive mortars produced in the tests to determine the consistency index, water retention, mass density, open time, tensile strength and water absorption by capillarity were analyzed. The results were satisfactory, demonstrating that it is feasible to use the waste as a substitute for sand in the production of industrialized adhesive mortars.

Microbial intrusion and seasonal dynamics in the groundwater microbiome of a porous basaltic rock aquifer used as municipal water reservoir

Groundwater is a key resource for safe drinking water supply. Yet unconfined aquifers can be vulnerable to microbial contamination during extreme weather events that lead to surface runoff. The current study characterises the groundwater microbiome of a porous basaltic rock aquifer in South-West Iceland used for drinking water extraction and analyses the microbial community dynamics during surface runoff. The groundwater microbial community sampled from twelve wells across the extraction area contained over 745 prokaryotic genera and was phylogenetically similar between wells and most seasons, representing a diverse but homogenous ecosystem. The largest seasonal variation in the microbial community composition was detected during a period of concurrent snow melt and high precipitation leading to surface runoff. This period was characterised by an increased abundance of soil-associated taxa in the groundwater microbiome and specifically of taxa assigned to Aeromonas and Bacillus. A field experiment simulating high surface runoff around a groundwater well confirmed the increased abundance of surface soil microorganisms in the well water, indicating vulnerability of groundwater towards surface microbial intrusion during extreme weather events. As such events are likely to increase due to climate change, novel water management tools such as microbial community analysis could help ensure drinking water safety.

Hydrothermal Activity at a Cretaceous Seamount, Canary Archipelago, Caused by Rejuvenated Volcanism

Our knowledge of venting at intraplate seamounts is limited. Almost nothing is known about past hydrothermal activity at seamounts, because indicators are soon blanketed by sediment. This study provides evidence for temporary hydrothermal circulation at Henry Seamount, a re-activated Cretaceous volcano near El Hierro island, close to the current locus of the Canary Island hotspot. In the summit area at around 3000–3200 m water depth, we found areas with dense coverage by shell fragments from vesicomyid clams, a few living chemosymbiotic bivalves, and evidence for sites of weak fluid venting. Our observations suggest pulses of hydrothermal activity since some thousands or tens of thousands years, which is now waning. We also recovered glassy heterolithologic tephra and dispersed basaltic rock fragments from the summit area. Their freshness suggests eruption during the Pleistocene to Holocene, implying minor rejuvenated volcanism at Henry Seamount probably related to the nearby Canary hotspot. Heat flow values determined on the surrounding seafloor (49 ± 7 mW/m2) are close to the expected background for conductively cooled 155 Ma old crust; the proximity to the hotspot did not result in elevated basal heat flow. A weak increase in heat flow toward the southwestern seamount flank likely reflects recent local fluid circulation. We propose that hydrothermal circulation at Henry Seamount was, and still is, driven by heat pulses from weak rejuvenated volcanic activity. Our results suggest that even single eruptions at submarine intraplate volcanoes may give rise to ephemeral hydrothermal systems and generate potentially habitable environments.