A 2000 year record of climate variations reconstructed from Haukadalsvatn,West Iceland

The sediment fill of Haukadalsvatn, a lake in northwest Iceland, preserves a record of environmental change since deglaciation, 13 ka ago. The rapid sedimentation rate over the past 2 ka (ca. 4 m ka⁻¹) provides a high-resolution archive of late Holocene environmental change. Physical and chemical environmental proxies extracted from cores from the Haukadalsvatn sediment fill provide a reconstruction of sub-decadal-scale climate variability in Iceland over the past 2 ka. Over this interval biogenic silica (BSi) reflects warm April–May temperatures, whereas total organic carbon (TOC) peaks represent an increased flux of carbon to the lake from eolian-derived soil erosion following periods of cold summers accompanied by dry, windy winters. The proxy-based temperature reconstructions show a broad interval of warmth through Medieval times, but this warmth is punctuated by multi-decadal cold intervals. The transition into the Little Ice Age occurred in two steps, with initial summer cooling 1250–1300 AD, and a more severe drop in summer temperatures between 1450 and 1500 AD; both are periods of severe explosive volcanism. Multi-decadal patterns of cold and warm conditions have some characteristics of a North Atlantic Oscillation (NAO)-like signal, but instrumental records and proxy-based reconstructions of the NAO index contain little power in the frequencies most strongly expressed in our data set. Although severe soil erosion in Iceland is frequently equated with settlement, our reconstructions indicate that soil erosion began several centuries before settlement, whereas for several centuries after settlement, when summer temperatures were relatively high, there was little or no soil erosion. Only during the transition into and during the Little Ice Age did soil erosion become a major feature of the record. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

ADM1‐Based Robust Interval Observer for Anaerobic Digestion Processes

A robust state estimation scheme is proposed for anaerobic digestion (AD) processes to estimate key variables under the most uncertain scenarios (namely, uncertainties on the process inputs and unknown reaction and specific growth rates). This scheme combines the use of the IWA Anaerobic Digestion Model No. 1 (ADM1), the interval observer theory and a minimum number of measurements to reconstruct the unmeasured process variables within guaranteed lower and upper bounds in which they evolve. The performance of this robust estimation scheme is evaluated via numerical simulations that are carried out under actual operating conditions. It is shown that under some structural and operational conditions, the proposed robust interval observer (RIO) has the property of remaining stable in the face of uncertain process inputs, badly known kinetics and load disturbances. It is also shown that the RIO is indeed a powerful tool for the estimation of biomass (composed of seven different species) from a minimum number of measurements in a system with a total of 32 variables from which 24 correspond to state variables.     

Temporal changes in the structure of the crustacean decapod assemblages associated with Cymodocea nodosa meadows from the Alboran Sea (Western Mediterranean Sea)

The decapod assemblages associated with two shallow meadows of Cymodocea nodosa, located in the same geographical area (Southern Spain) but on different substrates and with different patch size, have been analyzed. They display similar structure (diversity indices not significantly different), without a clear relation of richness and abundances to patch size, and with the same dominant species (the family Hippolytidae and, in particular, Hippolyte leptocerus are characteristic of this habitat). The composition of both crustacean assemblages is influenced by species that are common in neighbouring habitats. Therefore the connectivity among them is an important factor in the qualitative and quantitative structure of these decapod communities. Species richness appears to be higher than in Cymodocea meadows elsewhere in the Mediterranean and Atlantic at a similar depth, perhaps as a consequence of the biogeographical location and the high diversity and connectivity with surrounding biotopes. High evenness values are the result of the structure and location of these meadows, which are fragmented and interspersed with other biotopes (sandy and rocky bottoms), resulting in an ‘ecotone effect’. On the other hand, the structures of the decapod assemblages differ significantly according to sampling period. The abundance and species richness are both related to plant phenology and the dominant species present a positive correlation with the number of leaves per shoot. The maximum abundance of many species is coincident with the greatest seagrass development (spring – summer), which provides more resources (surface, biomass, protection, food). Therefore, seasonality is linked to plant life cycle, but also to the interrelationships and biology of the species, which are adapted and specialized to the environmental features of these shallow habitats.     

Relatively short-term correlation among deformation,degassing, and seismicity: a case study from Concepción volcano,Nicaragua

Concepción is a frequently active composite volcano in Nicaragua, and is located on Ometepe Island, within Lake Nicaragua. Significant eruptive activity took place at this volcano between March and May 2010, consisting of ash and gas explosions (VEI 1–2). We compare geodetic baseline changes observed with global positioning system (GPS), sulfur dioxide flux (SO₂), and seismic amplitude (SAM) data collected at Concepción during April – June, 2010, and February – April, 2011. Time series analysis reveals a remarkable correlation among the data sets during 2010, when the volcano was erupting. In contrast, the volcano was at its background level of activity in 2011 and the statistical correlation among the time series is not significant for this period. We explain the emergence of correlation among the time series during eruptive activity through modeling of the GPS data with emplacement of a magma column in an open conduit. In the model, magma rose in the conduit, between May 5 and 14, 2010, from a shallow reservoir located at ～ 1.8 km depth. Later, between May 24 and 31, 2010, the top of the magma column descended to almost 600 m depth, corresponding to the cessation of eruptive activity. Thus, cross-correlation and an integrated analysis of these geophysical time series on a timescale of days helps to reveal the dynamics of the magma plumbing system operating below Concepción volcano.     

Possible correlation between miocene global climatic changes and magnetic proxies,using neuro fuzzy logic analysis in a stratigraphic well at the Llanos foreland basin,Colombia

In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a correlation between global climatic changes (benthic foraminiferal δ¹⁸O data), experimental S-ratio (factor characterizing stability of remanent magnetization) and magnetic susceptibility (κ). Magnetic proxies have been measured in 44 samples of the Colombian stratigraphic well Saltarín 1A (distal Llanos foreland basin). κ and Sratios were linked to global δ¹⁸O data assuming a constant accumulation rate for a 305 meters thick stratigraphic interval flanked by the two palynological age constrains available. This interval encompasses, from top to base, the bottom of the Guayabo formation, the León, and the upper unit of the Carbonera formations (lower to middle Miocene). The best inference is accomplished applying a Takagi-Sugeno-Kan (TSK) fuzzy model with four fuzzy rules and the δ¹⁸O, S-ratios and κ data used in a linear form to train the system. These results are interpreted as the outcome of a significant influence of global climatic changes upon magnetic proxies. A stronger correlation is perhaps prevented by the likely influence of local and regional tectonic events and climatic changes that could have affected the distal segment of the Colombian Llanos foreland basin during Miocene times. We argue that late diagenesis of primary magnetic minerals and the assumption of a constant accumulation rate might have a minor influence on these results.     

The Pulpí gigantic geode (Almería, Spain): geology, metal pollution, microclimatology, and conservation

The discovery of the giant Geode of Pulpí (Almería, Spain) was considered as an important highlight in the geological heritage of Spain. Projects developed for their conservation were immediately initiated with legal figures of protection and tourist projects. The Geode has a tourist interest, which must be tempered by environmental restrictions limiting the public visits. First results demonstrate that a continuous visit of two or three people for more than 10 min provokes the appearance of condensation and risks corrosion of the gypsum crystals. In addition, the electron microprobe analyses confirms (1) the hydrothermal phases of iron–manganese in carbonated host rock; (2) the presence of sulphides with Fe–Zn–Pb–Ag–Sb–Cu–Hg–As–Te–Se; and (3) Ba, Ca, and Sr sulphates with mercury traces. The present proposal to label the geode and the mining environment as geological-natural heritage is feasible, although any tourist adaptation must not permit visits to the geode indoor and Hg levels must be controlled.     

Spherical particles as tracers of atmospheric ceramic industry

Castellón province houses the nucleus of ceramics production in Spain (93%). This nucleus, located around in the villages of Castellón, Villarreal, Alcora and Onda, has gone through a special process of industrial expansion. The emissions, most of them of particulate material, can constitute a real environmental problem. A study designed to identify the crystalline and glassy phases in the depositable particulate material has been carried out by SEM/EDX and X-ray diffraction methods. Quartz, calcite, illite, kaolinite, chlorite, and feldspars have been the main crystalline phases identified. The number of spherical morphology particles found in the depositable material is remarkable. The vitreous material found was spherical nodules. Due to the shape, size (1–10 μm), and chemical composition of these particles, they can be excellent tracers of the ceramics industry emissions.The presence of Zn, Ba, or Fe are due to the massive use of these substances as opacifying and pigmentation agents in many ceramics frits and glaze compositions. This fact gives a valuable information that will facilitate the studies guided to obtain important aims such as: toxicology, average size of a particle, formation mechanisms, etc.     

Application of satellite imagery in tectonic interpretation

The advabtages of remote sensing are widely used in geologic research. In Hungary, however, in the deep sedimentary basin and densely covered mountain areas, the methods which have been developed and which have led to significant result in arid and semiarid regions cannot be used effectively.In this case, our interest should be focused on detecting structural features instead of on lithologic discrimination. Consequently, this approach can be applied for only morphologically performed areas. A better understanding of the tectonics can be achieved by the evaluation of its morphological expressions.A block-shift method is described for the structural evaluation of linear features, and it is applied for one of the most controversial and least known tectonic units: the Mecsek Mts. (S-Hungary). This method is based on the calculation of several conditional frequencies of length, azimuth and shape for overlapping blocks.Our experience leads to the conclusion that the widely accepted East-West segmentation of the Mecsek Mts. should be changed. We have found an Eastern-Central-Western Mecsek structure which correlates well with some up-to-date geologic mapping results. The lithologic differences are enhanced by morphological and structural features.Besides its scientific achievements, the economic importance of this research is supported by the perspective of the utilization of non-renewable natural resources in the Mecsek Mts.