Biocrust landscape-scale spatial distribution is strongly controlled by terrain attributes: Topographic thresholds for colonization in a semiarid badland system

Biological soil crust, or biocrust communities, are the dominating life form in many extreme habitats, such as arid and semiarid badlands, where water scarcity and highly erodible substrates limit vegetation cover. While climate, soil and biotic factors have been described as environmental filters influencing biocrust distribution in such biomes, little is known about the effect of terrain attributes on creating specific microhabitats that promote or restrict biocrust colonization. This study aimed to identify the main terrain attributes controlling biocrust distribution in the driest badland system in Europe, the Tabernas Badlands (SE Spain). To do this, we analysed the influence of different terrain attributes related to landscape stability and microclimate formation on the spatial distribution of lichen and cyanobacteria, using field measurements and topographical information from a LiDAR survey. Our results showed that the spatial distribution of cyanobacteria-dominated biocrusts, which are physiologically and morphologically adapted to extreme drought and high UVA radiation, was mostly associated with areas of high potential incoming solar radiation. The exception was bare south-aspect hillslopes with very high sediment transport potential, where bare physically crusted soils were the dominant ground cover. Lichen-dominated biocrusts, in contrast, colonized near the top of north-aspect hillslopes, characterized by low potential incoming solar radiation and potential evapotranspiration, and their cover decreased downstream, as conditions became good enough for vascular plants. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.     

Influence of the natural organic matter in the removal of caffeine from water by fixed-bed column adsorption

The removal of caffeine from tap water by F-400 granular activated carbon in fixed-bed adsorption experiments was carried out. Textural and chemical characterization of the adsorbent through N₂ adsorption–desorption isotherms, Fourier transform infrared spectrometry, isoelectric point determination and scanning electron microscopy studies was developed in studies previously reported. Caffeine breakthrough curves and total organic carbon profiles at different operation conditions (inlet concentration, volumetric flow rate and mass of adsorbent) were obtained. These experimental results showed a displacement of the natural organic matter from the active sites exerted by caffeine molecules due to their higher affinity to the surface carbon. This behavior led to an overshooting, a local outlet natural organic matter concentration higher than the feed quantity. A competitive effect seems to be observed in the removal of the target compound, decreasing the efficiency of the process. Axial dispersion coefficients and dimensionless numbers were estimated for the caffeine removal onto F-400 activated carbon. Therefore, the regeneration of the adsorbent by adsorption–desorption cycles was studied.     

Slope instabilities triggered by the 11th May 2011 Lorca earthquake (Murcia,Spain): comparison to previous hazard assessments and proposition of a new hazard map and probability of failure equation

The Lorca Basin has been the object of recent research aimed at studying the phenomena of earthquake-induced landslides and its assessment in the frame of different seismic scenarios. However, it has not been until the 11th May 2011 Lorca earthquakes when it has been possible to conduct a systematic approach to the problem. In this paper we present an inventory of slope instabilities triggered by the Lorca earthquakes which comprises more than 100 cases, mainly rock and soil falls of small size (1–100  \(\hbox {m}^{3}\) ). The distribution of these instabilities is here compared to two different earthquake-triggered landslide hazard maps: one considering the occurrence of the most probable earthquake for a 475-years return period in the Lorca Basin \((\hbox {M}_{\mathrm{w}}=5.0)\) based on both low- and high-resolution digital elevation model (DEM); and a second one matching the occurrence of the \(\hbox {M}_{\mathrm{w}}=5.2\) 2011 Lorca earthquake, which was performed using the higher resolution DEM. The most frequent Newmark displacements related to the slope failures triggered by the 2011 Lorca earthquakes are lower than 2 cm in both the hazard scenarios considered. Additionally, the predicted Newmark displacements were correlated to the inventory of slope instabilities to develop a probability of failure equation. The fit seems to be very good since most of the mapped slope failures are located on the higher probability areas. The probability of slope failure in the Lorca Basin for a seismic event similar to the \(\hbox {M}_{\mathrm{w}}\) 5.2 2011 Lorca earthquake can be considered as very low (0–4 %).     

Tectonic setting of the recent damaging seismic series in the Southeastern Betic Cordillera,Spain

In this work we analyze the tectonic setting of the recent damaging seismic series occurred in the Internal Zones of the eastern Betic Cordillera (SE Spain) and surrounding areas, the tectonic region where took place the 11th May 2011 Mw 5.2 Lorca earthquake. We revisit and make a synthesis of the seven largest and damaging seismic series occurred from 1984 to 2011. We analyze their seismotectonic setting, and their geological sources under the light of recent advances in the knowledge on active faults, neotectonics, seismotectonics and stress regime, with special attention focused on the Lorca Earthquake. These seismic series are characterized by two types of focal mechanisms, produced mainly by two sets of active faults, NNW–SSE to NNE–SSW small (no larger than 20–30 km) extensional faults with some strike slip component, and E–W to NE–SW large strike slip faults (more than 50 km long) with some compressional component (oblique slip faults). The normal fault earthquakes related to the smaller faults are dominant in the interior of large crustal tectonic blocks that are bounded by the large E–W to NE–SW strike-slip faults. The strike slip earthquakes are associated to the reactivation of segments or intersegment regions of the large E–W to NE–SW faults bounding those crustal tectonic blocks. Most of the seismic series studied in this work can be interpreted as part of the background seismicity that occurs within the crustal blocks that are strained under a transpressional regime driven by the major strike slip shear corridors bounding the blocks. The seismotectonic analysis and the phenomenology of the studied series indicate that it is usual the occurrence of damaging compound earthquakes of M  \(\sim \)  5.0 associated with triggering processes driven by coseismic stress transfer. These processes mainly occur in the seismic series generated by NNW–SSE to NNE–SSW faults. These mechanical interaction processes may induce a higher frequency of occurrence of this kind of earthquakes than considered in traditional probabilistic seismic hazard assessments and it should be taken into account in future seismic hazard assessments.     

Scale-dependent correlations between soil heavy metals and As around four coal-fired power plants of northern Greece

We analyse the concentration of five trace elements (As, Cu, Ni, Pb and Zn) in the topsoil of the Kozani-Ptolemais basin where four coal-fired power plants run to provide almost 47.8 % of electricity requirements in Greece. We assume that if the power plants have altered the spatial (co)variation of the analysed elements through their toxic by-products, their effect would be observable only on a small spatial scale, since deposition of airborne pollutants is more evident if it is near the emission source. We used Factorial Cokriging to estimate the small-scale correlations among soil elements and to compare them to large spatial-scale correlations. Soil samples were collected from 92 sites. Given the low concentrations in soil heavy metals and As, we observed no serious soil contamination risk. We estimated correlations among the analysed elements on two spatial scales. On the larger scale, Ni and As exhibited higher correlation and received higher weights for the first regionalized factor, contrary to Cu, Pb and Zn which weighted more for the second regionalized factor. On the small spatial scale As associated with neither Ni nor other heavy metals. We conclude that soil arsenic has been altered by enrichment caused by some power plants through fly ash deposition and/or disposal. However, enrichment of soil elements was detectable only on the smaller spatial scale because anthropogenic inputs in soil through airborne emissions and subsequent deposition are evident only in the vicinity of the emission source.     

The 2011 submarine volcanic eruption in El Hierro (Canary Islands)

Forty years after the Teneguía Volcano (La Palma, 1971), a submarine eruption took place off the town of La Restinga, south of El Hierro, the smallest and youngest island of the Canarian Archipelago. Precursors allowed an early detection of the event and its approximate location, suggesting it was submarine. Uncertainties derived from insufficient scientific information available to the authorities during the eruption, leading to disproportionate civil protection measures, which had an impact on the island's economy—based primarily on tourism—while residents experienced extra fear and distress.     

Rotational atmospheric circulation during North Atlantic-European winter: the influence of ENSO

The dominant variability modes of the North Atlantic-European rotational flow are examined by applying a principal component analysis (PCA/EOF) to the 200?hPa streamfunction mid-winter anomalies (Jan?CFeb monthly means). The results reveal that, when this norm is used, the leading mode (EOF1) does not correspond to the traditional North Atlantic Oscillation (NAO, which appears in our analysis as the second leading mode, EOF2) but is the local manifestation of the leading hemispheric streamfunction EOF. The regression of this regional mode onto the global SST field exhibits a clear El Ni?o signature, with no signal over the Atlantic, while the associated upper height anomalies resemble the Tropical/Northern Hemisphere (TNH) pattern. East of North America, this TNH-like wavetrain produces a meridional dipole-like pattern at lower levels. Although in some ways this pattern resembles the NAO (EOF2), the dynamics of these two modes are very different in that only EOF2 is associated with a latitudinal shift of the North Atlantic stormtrack. Thus, the choice of the streamfunction norm in the EOF analysis allows the separation of two different phenomena that can produce similar dipolar surface pressure anomalies over the North Atlantic but that have different impact on European climate. These two modes also differ on their contribution to variability at lower levels: while NAO-EOF2 is mostly confined to the North Atlantic, TNH-EOF1 has a more annular, global character. At upper levels NAO-EOF2 also produces a global pattern but with no annular structure, reminiscent of the ??circumglobal?? teleconnection.     

Trace elements in Holocene sediments of the southern Doñana National Park (SW Spain): historical pollution and applications

The multidisciplinary analysis of core sediments from Doñana National Park, south Spain, permits to delimitate both the paleoenvironmental changes and the geochemical evolution of this area during the Holocene. In a first phase (10–6.5 kyr cal), this area was occupied by freshwater/brackish marshes with periodical alternation of dry periods and humid intervals. In a second phase, these marshes were inundated during the Flandrian transgression (~6.5 kyr cal), with the deposition of bioclastic sands. The third phase (6.5–3.6 kyr cal) is characterized by the transition to an old lagoon, with unpolluted, bottom sediments. The geochemical concentrations of these clayey sediments can be used as a geochemical background for present-day and future environmental evaluations of this area. In the following 600 years approximately, two tsunamis caused the partial infilling of this area with bioclastic, marine sediments. In the interval comprised between these two tsunamis, this lagoon was polluted with heavy metals derived from historical mining activities. This environmental contamination represents one of the oldest evidences of mining pollution in the world (>3 kyr cal BP).     

Ichnological data as a useful tool for deep-sea environmental characterization: a brief overview and an application to recognition of small-scale oxygenation changes during the Cenomanian�CTuronian anoxic event

The oceanic anoxic event at the Cenomanian?CTuronian transition (OAE-2) is a worldwide phenomenon related with variations in atmosphere?Cocean dynamics. This event coincides with significant changes in the palaeoenvironment determining marine mass extinction affecting numerous groups of organisms. Ichnological analysis of the Cenomanian?CTuronian boundary interval has been conducted in three selected sections from different ecological and depositional settings in the western Tethys. Indeed, a brief overview of existing knowledge in this domain highlights increasing recognition of the usefulness of trace fossils in the characterization of even minor-scale deep-sea environmental changes linked to sea-level dynamics. At the study sites, variations in ichnological features, including trace fossil composition, tiering patterns and ichnofabrics, can be related to fluctuations in bottom- and pore-water oxygenation during the Cenomanian?CTuronian interval. In the Barnasiówka section (Polish Outer Carpathians), changes between oxic/dysoxic??characterized by Chondrites, Planolites and even Thalassinoides??and euxinic conditions, without trace fossils or only with Chondrites, can be explained by variations in gravity flows influencing the benthic habitat. In the El Chorro and Hedionda sections (Betic Cordillera), longer anoxic intervals during the OAE-2, characterized by the absence of trace fossils, are interrupted by shorter dysaerobic and aerobic sub-events associated with Chondrites, Palaeophycus, Planolites, Thalassinoides, Trichichnus and Zoophycos, but showing significant differences between these two sections related to the palaeogeographically differentiated influence of upwelling conditions.