The sudden eruption of the Tonga underwater volcano (20.53°S, 175.38°W) on 15 January 2022 generated explosions that triggered blast waves traveling away from the eruption. In this study, the ...analysis of the geomagnetic field observations on the ground shows that the eruption perturbed the E‐region current density by 22–55 mA/m within a radius of 8,000 km away from the eruption. The perturbation evolved into large scales of ∼5 hr and thousands of kilometers as it traveled away. The traveling speed of the leading front is ∼740 m/s that is near acoustic in the ionosphere. The magnetic fields and total electron content observations suggest that the dynamics changes further induced significant ionospheric disturbances that lasted ∼10 hr after the eruption. The examination of the Tonga volcanic eruption inspires us that a near‐surface perturbation can change the dynamics of the upper atmosphere.
Plain Language Summary
As we drop a stone into the still water, the water piles up around the rock and induces ripples in the form of concentric circles that expand and travel away from the center point. A similar phenomenon happened in the atmosphere after the eruption of the Tonga underwater volcano (20.53°S, 175.38°W) at ∼04:15 UT on 15 January 2022. The Earth's atmosphere is a pond of air. The explosive eruption triggered prosperous waves, which is similar to dropping a stone into water. The waves, ripples, and disturbances in different spheres are fantastic due to the eruption (Figure S8 in Supporting Information S1). Besides the tsunamis, atmospheric concentric ripples, and ionospheric traveling disturbances, this study for the first time showed that the blast wave due to the eruption changed the dynamics of the ionosphere or thermosphere (upper atmosphere). It is well known that a significant volcanic eruption can release tremendous ashes and gases into the troposphere and stratosphere (lower atmosphere), which change the chemical and dynamic process there. The observations in this study surprisingly show that the eruption changed the dynamics of the upper atmosphere, where the volcanic cloud cannot reach.
Key Points
The eruption of the Tonga underwater volcano perturbed the E‐region current and, in turn, changed the geomagnetic field by ∼20–50 nT
A large near‐surface perturbation can modulate the ionospheric dynamics and further induce ionospheric disturbances
The significant ionospheric disturbances with periods ranging from several minutes to hours lasted more than 10 hr after the eruption
1. Large-scale destruction of ecosystems caused by surface mining provides an opportunity for the study of colonization processes starting with primary succession. Surprisingly, over several decades ...and without any restoration measures, most of these sites spontaneously developed into valuable biotope mosaics with many endangered plant species. 2. Investigations were carried out in 10 open-cast mined sites. Data from extensive floristic mapping of mined sites and their surroundings were combined with functional traits. 3. Using binary logistic regression, we showed that eight variables have a significant influence on the probability of the occurrence of particular plant species in mined sites. The regional species pool explained the highest proportion of variance. Further significant variables were distance of source populations, abundance in the habitat species pool, capacity for long-distance dispersal by wind and birds, terminal velocity of seeds and requirements for light and nitrogen. 4. In the 10 study mine sites, 143 establishing events of Red List species have been recorded. For 40% of these establishing events, the nearest recorded seed source is 3-10 km away, while for 19%, the distance to the nearest seed source exceeds 10 km. 5. This study showed for the first time that the abundance of species up to a distance of at least 17 km plays an important role in colonization processes following large-scale destruction of ecosystems. In large-scale, nutrient-deficient, open sites, an accumulation of plant species, including rare species, can be expected in time frames amenable to planning (several decades), because the sites acted as huge seed traps in the landscape. 6. Synthesis and applications. The floristic colonization probability of restoration sites is higher if large-scale, open and nutrient-poor habitats are available. In regions where such habitats have become highly fragmented, restoration planning of derelict land (e.g. surface mines, quarries, landfills) that supports the creation of such conditions can contribute to the regional survival of rare pioneer species. In future restoration planning, a new protocol must be established that combines the utilization of site potential with spontaneous colonization processes.
The relative importance of environmental factors and species pool in natural regeneration processes is still intensively disputed. Is environmental filtering especially important for species with ...higher requirements for temperature and soil fertility? Is the seed source limitation especially pronounced among tree species with lower dispersal abilities? Trees, seedlings and saplings measurements were conducted in 600 plots of 0.05 ha distributed in a regular grid in the Tatra Mountains (elevation range 817–1797 m a.s.l.). Boosted regression trees were used to analyse the relationships between the numbers of young trees, factors acting as environmental filters and the potential seed source availability. The most important factor affecting the distribution of young trees of most species was elevation; bedrock type was the second most important factor for
Acer pseudoplatanus
, while potential solar radiation was important for
Sorbus aucuparia
. The relationship between the presence of mature trees and abundance of young ones was strong in
Fagus sylvatica
, moderately strong in
A. pseudoplatanus,
and weak in
Picea abies, Abies alba
and
S. aucuparia
. The role of environmental factors in shaping the abundance of young trees varies strongly among species, while the seed source availability is very important for large-seeded trees.
A joint analysis of the monitoring data of interplanetary scintillations with solar and geophysical data showed that at the descending phase of the 24 solar activity cycle, the dominant role in ...geomagnetic disturbances, is associated with corotating disturbances in the solar wind. In 2018–2019, when approaching a deep minimum of activity, 12 of 13 strong magnetic storms were caused by the arrival of a compressed part of the interaction regions of flows of different velocities to the Earth. Only in one event, on May 11, 2019, the superposition of flare disturbances with the corotating one was observed. Comparison with the results of similar data in 2016 and 2017 shows the existence of corotating disturbances with a lifetime of at least several solar rotation. The conclusion is confirmed that 3–4 days before the compressed part of the perturbation arrives at the Earth, the evening and night scintillations begin to weaken, which can be interpreted as a significant decrease in the level of small-scale plasma turbulence in the extended region ahead of the perturbation frontal part. The weakening of the second scintillations in the evening sector with a duration of 2–3 days can be -considered as a precursor to the approach of a corotating perturbation to the Earth. As in 2016–2017, simultaneously with the magnetic storm, an intensification of the second’s scintillations occurs, which is most clearly recorded if the storm occurs in the evening or at night.
Observations and initial analysis of interplanetary scintillation data are briefly described in the framework of the program for the solar wind monitoring with the modernized LPI LPA radio telescope ...that started in 2014. The examples of detecting interplanetary coronal mass injections (ICME) and co-rotating interaction regions (CIR) of different-speed flows are presented. It is shown that in the first case, enhancements in the scintillation level in extended sounded regions of solar wind are observed 20–30 hours before the arrival of the disturbances to the Earth; in the second case, the evening and night scintillation level decrease is observed several days before the compressed region of disturbances comes to the Earth. These features are considered as a base of using interplanetary scintillation monitoring data for short-time space weather forecasting.
A statistical study has been performed on all the geomagnetic storm events caused by Coronal Mass Ejections (CMEs) which are associated with flares from January 2010 to December 2012. The following ...results are obtained. The sources of the CMEs mentioned above are distributed mainly from 45°E to 45°W on the solar surface, accounting 78.95% of the total events, and most of them are distributed in the western hemisphere, thus the sources of CMEs located in the western hemisphere are more likely to cause geomagnetic effects. The X-class flares are more likely to be associated with geomagnetic effects, and geomagnetic storms will be observed in two or three days after the eruption of 60% of X-class flares, while the flares of other classes have a much lower probability to associate with geomagnetic effects, less than 10% for all of them. By analyzing all the X-class flares erupted during this period on the solar disk, it is found that for the X-class flares located from 45°E to 45°W in heliographic longitude, if there are no large-scale disturbances on the solar surface nor the accompanied CMEs during the eruptions, the probability of occurrence of geomagnetic storms after the flares will be very small. Therefore, a new method to forecast the geomagnetic storms by analyzing the observed solar image data has been proposed.
Approximately 40,500 ha of Spartina-dominated marshes died during a drought-induced disturbance in Louisiana. This caused concern because in the absence of recovery, dieback marshes can subside, ...increasing the present high rates of wetland loss in coastal Louisiana. We assessed the recovery of one such dieback area after hydraulically dredged sediment-slurries were applied to the site to compensate for post-dieback soil consolidation. Five treatment-levels resulted from the sediment-slurry addition: 1) high elevation 2) medium elevation, 3) low elevation, 4) pop-up, and 5) vegetated. Plant recruitment within the five sediment treatment-levels were compared to two types of reference marshes: 1) ambient marshes, which neither died-back nor received sediment-enrichment, and 2) dieback marshes, which did not receive sediment addition. High and medium elevations had minimal recovery two years following the slurry addition, similar to that in reference dieback marshes. The low elevation, pop-up (highly organic sections of the original substrate that detached during slurry application and settled on top of the sediment-slurry), and vegetated (dieback areas that recovered by the start of the study) treatment-levels, all of which received sediment-slurry application, had rapid plant recovery. Plant recolonization was governed by optimal inundation, high organic matter content at high elevation, and rhizome survivability following sediment burial. If applied appropriately, sediment-slurry amendments can restore salt marshes submerging due to subsidence or other events, like sea-level rise, that may result in excessive plant submergence.
In the debate on the stability of savanna vegetation, spatial processes are often neglected. A spatial simulation model based on a cellular automata approach was constructed to identify the factors ...and processes crucial to the coexistence of trees and grass, and their effects on the spatial arrangement of trees in arid and semiarid savannas. 2 The simulation shows that the traditional key determinants of savannas-rain, fire and grazing-generate and sustain a coexistence of trees and grasses only under specific conditions. 3 An increase in the rainfall (improved tree establishment) or in grazing (reduced competition from grass), led to an increase in the woody component in the model. Where this trend was reversed by occasional fires, the simulation indicated that trees would be patchily distributed in thickets that excluded fire. 4 For an intermediate range of fire, grazing and rainfall variables this strongly clumped distribution pattern of trees represented a stable tree-grass mixture for more than 20 000 simulated years. 5 The hypothesis is formulated that factors or processes other than competition for moisture, herbivory and fire are needed in addition to induce a long-term persistence of scattered trees. 6 By exploring the long-term and spatial consequences of altering the variables that were thought to be key determinants of savanna vegetation, this spatiotemporal model provides a novel insight into the understanding of savanna dynamics.
Tropical forests vary substantially in the densities of trees of different sizes and thus in above-ground biomass and carbon stores. However, these tree size distributions show fundamental ...similarities suggestive of underlying general principles. The theory of metabolic ecology predicts that tree abundances will scale as the -2 power of diameter. Demographic equilibrium theory explains tree abundances in terms of the scaling of growth and mortality. We use demographic equilibrium theory to derive analytic predictions for tree size distributions corresponding to different growth and mortality functions. We test both sets of predictions using data from 14 large-scale tropical forest plots encompassing censuses of 473 ha and > 2 million trees. The data are uniformly inconsistent with the predictions of metabolic ecology. In most forests, size distributions are much closer to the predictions of demographic equilibrium, and thus, intersite variation in size distributions is explained partly by intersite variation in growth and mortality.
Summary
Large‐scale disturbances can be important components of the temporal landscape of natural ecosystems, but generalities regarding ecosystem impacts are difficult due to their infrequent and ...unpredictable nature. Volcanic eruptions figure as one of the most prominent of these natural disturbances, but the effects on microbes and ground‐dwelling arthropods, which modulate carbon and nutrient turnover, are relatively unknown.
We evaluated the effects of the 2011 Puyehue‐Cordón Caulle eruption in Patagonia, Argentina, on the litter and soil microbial and faunal communities in natural and afforested semi‐arid ecosystems located 70 km west of the epicentre of the eruption. We hypothesized that volcanic ash deposition would strongly reduce soil faunal and microbial communities due to insecticidal effects of ash on arthropods, with a concomitant reduction in ecosystem processes.
Our objective was to quantify the impact of the volcanic eruption by comparing pre‐ and post‐eruption time points in the same study site, with nearly identical field methodology. We measured environmental variables of soil and litter moisture, pH, microbial biomass, and soil and litter microbial enzymatic activity. We evaluated ground‐dwelling arthropods and nematodes using pitfall traps and soil extraction, respectively. Additionally, a parallel, controlled‐condition experiment of simulated ash deposition was conducted to evaluate ash effects on litter decomposition and enzymatic activity.
In the field, post‐eruption soils had lower soil water content, pH and soil organic matter. Additionally, nematode abundance and soil microbial enzyme activity were significantly reduced. In contrast, ground‐dwelling arthropods and litter enzymatic activity increased significantly. Finally, with simulated ash deposition, litter decomposition increased fourfold for native litter decomposition.
Large‐scale disturbances may play a key role in biogeochemical cycling in affected natural ecosystems, but not necessarily due to their catastrophic effects. In contrast to our original predictions, we observed a marked stimulation of biotic activity and carbon turnover in the aftermath of the Puyehue volcanic eruption, which demonstrates that the biotic component of these ecosystems has a substantial capacity to respond to these disturbances in short time frames. These results can contribute to placing the role of these large‐scale infrequent disturbances in a more robust ecological context.
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