9000 years of changes in peat organic matter composition in Store Mosse (Sweden) traced using FTIR-ATR     

Antonio Martínez Cortizas  Jenny K. Sjöström  Eleonor E. Ryberg  Malin E. Kylander  Joeri Kaal  Olalla López-Costas  Noemi Álvarez Fernández  Richard Bindler 《Boreas: An International Journal of Quaternary Research》2021,50(4):1161-1178

Store Mosse (the ‘Great Bog’ in Swedish) is one of the most extensive bog complexes in southern Sweden (~77 km²), where pioneering palaeoenvironmental research has been carried out since the early 20th century. This includes, for example, vegetation changes, carbon and nitrogen dynamics, peat decomposition, atmospheric metal pollution, mineral dust deposition, dendrochronology, and tephrochronology. Even though organic matter (OM) represents the bulk of the peat mass and its compositional change has the potential to provide crucial ecological information on bog responses to environmental factors, peat OM molecular composition has not been addressed in detail. Here, a 568-cm-deep peat sequence was studied at high resolution, by attenuated reflectance Fourier-transform infrared spectroscopy (FTIR-ATR) in the mid-infrared region (4000–400 cm^–1). Principal components analysis was performed on selected absorbances and change-point modelling was applied to the records to determine the timing of changes. Four components accounted for peat composition: (i) depletion/accumulation of labile (i.e. carbohydrates) and recalcitrant (i.e. lignin and other aromatics, aliphatics, organic acids and some N compounds) compounds, due to peat decomposition; (ii) variations in N compounds and carbohydrates; (iii) residual variation of lignin and organic acids; and (iv) residual variation of aliphatic structures. Peat decomposition showed two main patterns: a long-term trend highly correlated to peat age (r = 0.87), and a short-term trend, which showed five main phases of increased decomposition (at ~8.4–8.1, ~7.0–5.6, ~3.5–3.1, ~2.7–2.1 and ~1.6–1.3 ka) – mostly corresponding to drier climate and its effect on bog hydrology. The high peat accumulation event (~5.6–3.9 ka), described in earlier studies, is characterized by the lowest degree of peat decomposition of the whole record. Given that FTIR-ATR is a quick, non-destructive, cost-effective technique, our results indicate that it can be applied in a systematic way (including multicore studies) to peat research and provide relevant information on the evolution of peatlands.  相似文献   

Energy balance and evaporation loss of an agricultural reservoir in a semi‐arid climate (south‐eastern Spain)     

B. Gallego‐Elvira  A. Baille  B. Martín‐Górriz  V. Martínez‐Álvarez 《水文研究》2010,24(6):758-766

A typical agricultural water reservoir (AWR) of 2400 m² area and 5 m depth, located in a semi‐arid area (southern Spain), was surveyed on a daily basis for 1 year. The annual evaporation flux was 102·7 W m^?2, equivalent to an evaporated water depth of 1310 mm year^?1. The heat storage rate G exhibited a clear annual cycle with a peak gain in April (G ～ 45 W m^?2) and a peak loss in November (G ～ 40 W m^?2), leading to a marked annual hysteretic trend when evaporation (λE) was related to net radiation (R_n). λE was strongly correlated with the available energy A, representing 91% of the annual AWR energy loss. The sensible heat flux H accounted for the remaining 9%, leading to an annual Bowen ratio in the order of 0·10. The equilibrium and advective evaporation terms of the Penman formula represented 76 and 24%, respectively, of the total evaporation, corresponding to a annual value of the Priestley–Taylor (P–T) coefficient (α) of 1·32. The P–T coefficient presented a clear seasonal pattern, with a minimum of 1·23 (July) and a maximum of 1·65 (December), indicating that, during periods of limited available energy, AWR evaporation increased above the potential evaporation as a result of the advection process. Overall, the results stressed that accurate prediction of monthly evaporation by means of the P–T formula requires accounting for both the annual cycle of storage and the advective component. Some alternative approaches to estimating R_n, G and α are proposed and discussed. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Some elements of mathematical information theory and total inversion algorithm applied to travel time inversion     

M. D. Martínez  X. Lana 《Pure and Applied Geophysics》1991,137(1-2):113-132

The total inversion algorithm and some elements of Mathematical Information Theory are used in the treatment of travel-time data belonging to a seismic refraction experiment from the southern segment (Sardinia Channel) of the European Geotraverse Project. The inversion algorithm allows us to improve a preliminary propagating model obtained by means of usual trial and error procedure and to quantify the resolution degree of parameters defining the crust and upper mantle of such a model. Concepts related to Mathematical Information Theory detect some seismic profiles of the refraction experiment which give the most homogeneous coverage of the model in terms of number of trajectories crossing it. Finally, the efficiency of the inversion procedure is quantified and the uncertainties regarding knowledge of different parts of the model are also evaluated.  相似文献   

A Parametric Approach for Dealing with Compositional Rounded Zeros   总被引：2，自引：0，他引：2  

Javier Palarea-Albaladejo  Josep A. Martín-Fernández  Juan Gómez-García 《Mathematical Geology》2007,39(7):625-645

In this work, a parametric approach for replacing data below the detection limit, also known as rounded zeros, in compositional data sets is proposed. Compositional rounded zeros correspond to small proportions of some whole that cannot be reliably detected by the analytical instruments under given operating conditions. This kind of zeros appear frequently in the data collection process in geosciences. They must be treated in an adequate way before some multivariate analysis can be applied. Our procedure results from a modification of the Expectation-Maximization (EM) algorithm and is based on the additive log-ratio transformation. Its coherence with the nature of compositional data and with basic operations in the simplex sample space is checked. Using real data sets, we find that this approach improves other parametric and non-parametric techniques for compositional rounded zeros.  相似文献   

Heavy metals pollution of aquatic ecosystems in the vicinity of a recently closed underground lead-zinc mine (Basque Country, Spain)   总被引：3，自引：0，他引：3  

M. Marqués  E. Martínez-Conde  J. Rovira  S. Ordóñez 《Environmental Geology》2001,40(9):1125-1137

A presentation is made of the study of an underground polymetallic sulphide mine and the pollution caused by this in the adjoining aquatic ecosystems. Troya Mine is in the Basque Cantabrian region (northern Spain). The annual production of the ore deposit of over 3.7 million tons of Pb (0.9%), Zn (11.2%) and Cu (0.2%) was 300,000 t. It was open and producing from 1986-1993. The mineralization was made up of pyrite, marcasite, sphalerite, galena, chalcopyrite and arsenopyrite. Only the Zn and the Pb were mined. We studied the distribution and behaviour of the heavy metals Zn, Pb, Fe, Mn, Cu, Cr and Cd in the water column, dissolved and suspended fractions, and in the sediments of Estanda Stream and of Gezala Creek. Zn, Cd and Mn tend to be found in the water; Fe, Pb, Cu and Cr appear as an adsorbed fractionin the solid phases. Those of the second group are significantly linked to the fluvial sediments and present very high levels. The concentrations of the metals are conditioned by the waters from the mine galleries, by the leached waste, by the surface runoff, and by overflow from the spillway of the tailings pond. Our observations provide knowledge on the extent of the polluting power of the metals, the physico-chemical effects in play and the subsequent chances of recovering these highly affected environments.  相似文献   

Groundwater contamination: risk management and assessment for landfills in Mar del Plata, Argentina   总被引：3，自引：0，他引：3  

E. Bocanegra  H. Massone  D. Martínez  E. Civit  M. Farenga 《Environmental Geology》2001,40(6):732-741

 This study presents a program for risk management in the contamination of groundwater resulting from leachate in landfills at Mar del Plata (Argentina). The program includes prediction, prevention, monitory observation and mitigation as actions that must be taken prior to, during, and after contamination occurs. This routine aids in the identification of weak points and failures of the program for those who are in charge of making decisions, and will allow better use of limited financial and technical resources based on planning, thus minimizing disconnected determinations. Results of the prediction stage were confirmed through monitoring. The presence of a plume of contamination more than 100 m from the landfill was shown, thus proving that implementation of a monitoring plan to follow the development of the contaminated plume must be implemented, particularly in populated areas which depend on residential wells for their water supply. Received: 8 May 2000 · Accepted: 14 August 2000  相似文献   

The Middle Jurassic radiolarites and pelagic limestones of the Nieves unit (Rondaide Complex, Betic Cordillera): basin starvation in a rifted marginal slope of the western Tethys     

Luis O'Dogherty  Agustín Martín-Algarra  Hans-Jürgen Gursky  Roque Aguado 《International Journal of Earth Sciences》2001,90(4):831-846

Middle Jurassic radiolarites and associated pelagic limestones occur in the Rondaide Nieves unit of the Betic Cordillera, southern Spain. The Rondaide Mesozoic includes: (a) a thick succession of Triassic platform carbonates, comparable to the Alpine Hauptdolomit and Kössen facies; (b) Lower Jurassic pelagic limestones comparable to the Alpine Hierlatz and Adnet facies; (c) the Middle Jurassic Parauta Radiolarite Formation, described herein; and (d) a thin Upper Jurassic-Cretaceous condensed limestone succession. The Parauta Radiolarite Formation and associated limestones were studied with respect to stratigraphy, petrography, micropalaeontology (radiolarians, calcareous nanno- and microfossils) and facies. Radiolarite sedimentation occurred in the Middle Bathonian in a restricted and dysoxic deep Nieves basin, perched in the distal zone of a continental margin fringing the Tethyan ocean. This margin was adjacent to a young narrow oceanic basin between the South-Iberian margin and a continental block called Mesomediterranean Terrane. The Nieves basin was part of a marine corridor between the Proto-Atlantic and Piedmont-Ligurian basins of the Alpine Tethys. The regional tectonic position, the stratigraphical evolution since the Triassic, the age and the nature of the Mesozoic facies and the palaeogeographic relations to adjacent domains show striking analogies between the Betic Rondaide margin and coeval units of the Alps.  相似文献   

Radio Emission from Three-dimensional Relativistic Hydrodynamic Jets: Observational Evidence of Jet Stratification     

Aloy MA  Gómez JL  Ibáñez JM  Martí JM  Müller E 《The Astrophysical journal》2000,536(2):L85-L88

High-resolution, high signal-to-noise ratio, blue-violet spectra of three red giant branch tip stars in M15 have been obtained with the Keck I High-Resolution Echelle Spectrograph. These spectra have been analyzed to determine the abundances of several neutron-capture elements, including the radioactive chronometer element thorium. There are two principal results of this study. First, the abundances of the heavier (Z>/=56) elements for each of the three stars is well matched by a scaled solar system r-process abundance distribution. Second, a weighted mean-observed Th/Eu ratio for the stars implies an age for the neutron-capture material in M15 stars of 14+/-3 Gyr, in reasonable agreement with other recent age estimates for Galactic globular clusters.  相似文献   

A Lost Realm in the Internal Domains of the Betic-Rif Orogen (Spain and Morocco): Evidence from Conglomerates and Consequences for Alpine Geodynamic Evolution     

Martín-Algarra A  Messina A  Perrone V  Russo S  Maate A  Martín-Martín M 《The Journal of geology》2000,108(4):447-467

The Malaguide-Ghomaride Complex is capped by Upper Oligocene-Aquitanian clastic deposits postdating early Alpine orogenesis but predating the main tectonic-metamorphic evolution, end of nappe emplacement, unroofing, and exhumation of the metamorphic units of the Betic-Rif Orogen. Two conglomerate intervals within these deposits are characterized by clasts of sedimentary, epimetamorphic, and mafic volcanic rocks derived from Malaguide-Ghomaride units and by clasts of acidic magmatic and orthogneissic rocks of unknown provenance, here studied. Magmatic rocks originated from late-Variscan two-mica cordierite-bearing granitoids and, subordinately, from aplitic dikes. Orthogneisses derive from similar plutonic rocks but are affected by an Alpine metamorphic overprint evolving from greenschist (T=510&j0;-530 degrees C and P=5-6 kbar) to low-temperature amphibolite facies (T>550&j0;C and P<3 kbar). Such a plutonic rock suite is unknown in any Betic-Rif unit or in the basement of the Alboran Sea, and the metamorphic evolution in the orthogneisses is different from (and older than) that of Alpujarride-Sebtide rocks to which they were formerly ascribed. Magmatic and metamorphic rocks very similar to those studied characterize the basements of some Kabylia and Calabria-Peloritani units. Therefore, the source area is a currently lost continental-crust realm of Calabria-Peloritani-Kabylia type, located to the ESE of the Malaguide-Ghomaride Domain and affected by a pre-latest Oligocene Alpine metamorphism. Increasingly active tectonics transformed this realm into rising areas from which erosion fed small subsiding synorogenic basins formed on the Malaguide-Ghomaride Complex. This provenance analysis demonstrates that all these domains constituted a single continental-crust block until Aquitanian-Burdigalian times, before its dispersal around nascent western Mediterranean basins.  相似文献   

Validation of a homogeneous 41-year (1961–2001) winter precipitation hindcasted dataset over the Iberian Peninsula: assessment of the regional improvement of global reanalysis     

M. G. Sotillo  M. L. Martín  F. Valero  M. Y. Luna 《Climate Dynamics》2006,27(6):627-645

A 44-year (1958–2001) homogeneous, Mediterranean, high-resolution atmospheric database was generated through dynamical downscaling within the HIPOCAS (Hindcast of Dynamic Processes of the Ocean and Coastal Areas of Europe) Project framework. This work attempts to provide a validation of the monthly winter HIPOCAS precipitation over the Iberian Peninsula and the Balearic Islands and to evaluate the potential improvement of these new hindcasted data versus global reanalysis datasets. The validation was performed through the comparative analysis with a precipitation database derived from 4,617 in situ stations located over Iberia and the Balearics. The statistical comparative analysis between the observed and the HIPOCAS fields highlights their very good agreement not only in terms of spatial and time distribution, but also in terms of total amount of precipitation. A principal component analysis is carried out, showing that the patterns derived from the HIPOCAS data largely capture the main characteristics of the observed field. Moreover, it is worth to note that the HIPOCAS patterns reproduce accurately the observed regional characteristics linked to the main orographic features of the study domain. The existence of high correlations between the hindcasted and observed principal component time series gives a measure of the model performance ability. An additional comparative study of the HIPOCAS winter precipitation with global reanalysis data (NCEP and ERA) is performed. This study reveals the important regional improvement in the characterization of the observed precipitation introduced by the HIPOCAS hindcast relative to the above global reanalyses. Such improvement is effective not only in terms of total amount values, but also in the spatial distribution, the observed field being much more realistically reproduced by HIPOCAS than by the global reanalysis data.  相似文献