Restes de vida en un cràter de fa 1 milió d'anys

A la superfície de la terra resten escrits els capítols de la nostra història. A vegades, de forma molt evident. Aquest és el cas dels cràters d'impacte, depressions del terreny que deixa un meteorit al seu pas per la superfície d'un cos sòlid. Lluny de només ser quelcom meravellós de la natura, les conseqüències biològiques i climàtiques de l'arribada d'aquests cossos extraterrestres s'han d'estudiar. I Bosumtwi també. Fa 1,07 milions d'anys un meteorit va impactar a terres africanes (Ghana) i va deixar com a testimoni a aquest cràter. Investigadors de l'Institut de Ciència i Tecnologia Ambientals de la Universitat Autònoma de Barcelona (ICTA), en col·laboració amb altres centres de recerca, analitzen la presència de restes de vida. Concretament, d'arquees, els microorganismes unicel·lulars més antics que coneixem. L'estudi s'ha centrat en els lípids presents a la membrana del microorganisme, donat que poden donar informació climàtica del passat i explicar la seva presència en roques enterrades al llac del cràter. Les hipòtesis resulten molt interessants.En la superficie de la tierra quedan escritos los capítulos de nuestra historia. A veces, de forma muy evidente. Este es el caso de los cráteres de impacto, depresiones del terreno que deja un meteorito a su paso por la superficie de un cuerpo sólido. Lejos de tan sólo ser algo maravilloso de la naturaleza, las consecuencias biológicas y climáticas de la llegada de estos cuerpos extraterrestres han de ser estudiados. Y Bosumtwi también. Hace 1,07 millones de años un meteorito impactó en tierras africanas (Ghana) y dejó como testigo a este cráter. Investigadores del Institut de Ciància i Tecnologia Ambientals de la Universitat Autònoma de Barcelona (ICTA), en colaboración con otros centros de investigación, analizan la presencia de restos de vida. Concretamente, de arqueas, los microorganismos unicelulares más antiguos que conocemos. El estudio se ha centrado en los lípidos presentes en la membrana del microorganismo, ya que pueden dar información climática del pasado y explicar su presencia en rocas enterradas en el lago del cráter. Las hipótesis resultan muy interesantes.The chapters of our history are written on the surface of the Earth. Sometimes in a very visible manner. This is the case of impact craters, a depression resulting from the impact of a meteorite with the surface of a solid object. Far from being a simple marvel of nature, there is a need to study the biological and climatic consequences caused by the arrival of these objects from outer space. This is the case of Lake Bosumtwi. Some 1.07 million years ago a meteorite hit African soil - in Ghana - and as a result a crater was formed. Researchers at the Institute of Environmental Sciences and Technologies (ICTA) at Universitat Autònoma de Barcelona, in collaboration with other research centres, have analysed the existence of these signs of life. Special interest was put into the research of archaea, the oldest single cell microorganisms known to man. The research focuses on the lipids present in the membrane of the microorganism, since they offer information on the climatic conditions of the past, and explains why these microorganisms can be found on the rocks at the bottom of the crater lake

Reconstruint les temperatures del passat

L'anàlisi dels arqueobacteris, els organismes més antics que es coneixen al nostre planeta, ens poden aportar moltes dades sobre les temperatures dels mars i dels llacs fa milers d'anys i ajduar a reconstruir la historia climàtica de la Terra. Investigadors de l'ICTA (Institut de Ciència i Tecnologia Ambientals) han millorat el mètode existent fins ara per analitzar-los i han aconseguit reduir el temps d'anàlisi per mostra d'1 hora a 8 minuts.El análisis de las arqueobacterias, los organismos más antiguos que se conocen en nuestro planeta, aporta muchos datos sobre las temperaturas de mares y lagos de hace miles de años y ayuda a los científicos a reconstruir la historia climática de la Tierra. Investigadores del ICTA (Insituto de Ciencia y Tecnologia Ambientales) han mejorado el método existente hasta ahora para analizarlos y han conseguido reducir el tiempo de análisis por muestra de 1 hora a 8 minutos.The analysis of archeobacteria, the oldest organisms in our planet, can contribute to discovering the temperatures seas and lakes had thousands of years ago and reconstructing the Earth's climate history. ICTA researchers have improved the existing method for analyzing them, by reducing the time of analysis by sample from 1 hour to 8 minutes

Application of tetraether membrane lipids as proxies for continental climate reconstruction in Iberian and Siberian lakes

Consultable des del TDXTítol obtingut de la portada digitalitzadaA portada: Institut de Ciència i Tecnologia AmbientalsDes del 2002, s'han desenvolupat una sèrie de proxies climàtiques basades en biomarcadors derivats d'arquees i bacteris. Aquests biomarcadors són els glicerol dialquil glicerol tetraèters o GDGTs. D'entre aquestes proxies, l'índex TEX86 s'aplica en sediments per tal de reconstruir les temperatures superficials del mar i dels llacs; els índexs MBT i CBT són utilitzats conjuntament per a reconstruir la temperatura superficial de l'aire i l'índex BIT permet avaluar la contribució relativa de material provinent del sòl i material pelàgic en els sediments. A causa del recent desenvolupament d'aquestes proxies, hi ha encara un gran nombre d'aspectes metodològics i d'aplicació que han estat poc estudiats. Per això, l'objectiu d'aquesta tesi ha estat la comparació i optimització de diversos procediments analítics implicats en la determinació dels GDGTs, així com l'estudi d'aquests biomarcadors en nous ambients, amb especial atenció en els llacs. En la part analítica d'aquesta tesi, s'ha comparat el mètode estàndard de clean-up de les mostres basat en el fraccionament de lípids en alúmina amb la hidròlisi alcalina; a més, s'han comparat diversos adsorbents i graus d'activació per al fraccionament dels lípids. Els resultats demostren que el TEX86 és robust respecte a aquestes tècniques, mentres que l'índex BIT depèn del grau d'activació de l'adsorbent. En la cromatografia, s'han dut a terme una reducció del flux i un augment de la velocitat dels anàlisis sense pèrdua de resolució cromatogràfica. Finalment, s'han utilitzat dos espectròmetres de masses de disseny diferent per a mesurar els índexs TEX86 i BIT i se n'ha confirmat la comparabilitat. Per altra banda, s'ha observat una sensibilitat extrema del BIT respecte a les condicions d'optimització dels espectròmetres. S'ha estudiat les concentracions dels GDGTs en els sediments superficials d'un conjunt de 38 llacs de la Península Ibèrica per tal d'identificar els factors que en determinen la distribució relativa. L'anàlisi de components principals indica que la major part de la variança pot explicar-se amb l'origen dels GDGTs (del sòl o lacustre), el grau de ciclització interna i el grau de metilació dels GDGTs. Els resultats demostren que les proxies MBT/CBT i el TEX86 tenen una utilitat limitada en la predicció de les temperatures d'aquests llacs, possiblement perquè la distribució de GDGTs és determinada per una mescla complexa de factors. Utilitzant l'anàlisi de clusters s'ha identificat un subconjunt de llacs on els índexs TEX86 i MBT/CBT mantenen una relació linial forta amb les temperatures instrumentals de l'aire. L'estudi dut a terme al llac Baikal (Sibèria) combina els resultats de trampes de sediment, sediments superficials i dos testimonis sedimentaris que corresponen a l'últim cicle glacial-interglacial. Els valors per a l'índex BIT al sediment suggereixen una contribució minsa de material provinent del sòl i les temperatures superficials del llac derivades de l'índex TEX86 es troben dins el rang anual de les mesures de temperatures superficials. En els testimonis sedimentaris, les variacions en profunditat del TEX86 i l'MBT/CBT revelen un senyal climàtic que es concreta en el registre de la transició de condicions glacials a interglacials i l'acord parcial amb les reconstruccions climàtiques existents per a la regió del llac Baikal derivades d'altres proxies. En darrer lloc, l'estudi exploratori dut a terme al cràter del Bosumtwi (Àfrica) revela la presència de GDGTs en les roques impactades i es discuteixen tres hipòtesis en referència a l'origen dels GDGTs trobats. El treball presentat amplia el rang de tècniques analítiques que poden utilitzar-se de forma fiable per a la mesura dels índexs basats en GDGTs i profunditza en l'aplicació i validació dels GDGTs com a proxies climàtiques en sediments lacustres, particularment de la Península Ibèrica i Sibèria.Since 2002, several climate proxies based on biomarkers of Archaea and Bacteria, the GDGTs, have been developed and applied in sedimentary archives worldwide. Among the proposed proxies, the TEX86 index is applied in sediments to reconstruct sea surface temperatures (SST) and lake surface temperatures (LST); The MBT and CBT indices are together applied as a proxy for past surface air temperature and the BIT index is measured in sediments to assess qualitatively relative inputs of pelagic-originated material versus soil material. Given the novelty of these proxies, there is plenty of scope to improve upon a range of issues regarding their measurement and application. Consequently, the aim of this thesis has been to tackle analytical methodological issues to gain in analytical reliability and sample throughput, and expand the range of environments where GDGT proxies have been appraised, particularly in lake environments. In the analytical section of the thesis, two sample clean-up methods, i.e. alumina fractionation and alkaline hydrolysis are compared. Additional tests compare alumina and silica in their activated and deactivated states as adsorbents onto which GDGTs are fractionated. Results show that TEX86 values are robust using these methodologies, while BIT values are dependant on adsorbent activation state. Regarding the chromatographic analysis, an increase in the analysis velocity and a reduction of flow are effectively implemented without loss of chromatographic peak resolution. Additionally, two mass spectrometer designs, i.e. an ion-trap system and a quadrupole system, are used for the measurement of a wide range of values of TEX86 and BIT indices, and results confirm the comparability of both systems. However, BIT values are found to be extremely sensitive to the MS tuning conditions. In order to find out the main factors influencing the GDGTs distribution in lacustrine environments, a suite of surface sediments from 38 Iberian lakes are surveyed. Principal component analysis of the relative concentrations of GDGTs indicates that terrestrial versus lacustrine origin, combined with degree of cyclization and degree of methylation of the lipids are the principal factors accounting for the GDGT distribution in the sediments. The measurement of the MBT/CBT proxy represents a pioneer application of these indices in lake sediments. TEX86 and MBT/CBT are shown to have a limited applicability in predicting the lake temperature, likely due to a complex combination of factors influencing the GDGT abundances. Using cluster analysis a subset of lakes is selected with a rather linear relationship of TEX86 and CBT/MBT with instrumental air temperatures. In the study conducted in lake Baikal in Siberia, sediment traps, surface sediments and two cores spanning the last glacial-interglacial cycle are analysed in the north and south basins of the lake. BIT values both for the particulate material collected and the surface sediments suggest low influence of soil-derived material. TEX86 derived LST from the water column particulate material and sediments are in the range of measured annual LST. The down-core variations of the TEX86 and MBT/CBT proxies reveal a climatic signal, inferred both from the reconstructed transition from glacial to interglacial conditions and the partial agreement with reconstructed changes in Lake Baikal region derived from other proxies applied in the sediments. The work presented extends the range of analytical techniques that can be reliably used for the measurement of the GDGT indices and provides deeper knowledge on the application and validation of GDGTs as climate proxies in lacustrine sediments, in particular from the Iberian and Siberian regions

Drivers of atmospheric CO2 concentrations over glacial to interglacial time scales

Les concentracions de CO2 han canviat de forma regular durant els darrers 650,000 anys, entre uns valors fixos màxims durant breus períodes interglacials, i mínims durant períodes glacials molt més prolongats. Aquesta variabilitat natural té lloc en paral·lel a canvis en diferents variables climàtiques durant el mateix interval la qual cosa suggereix una connexió causal entre el clima i el CO2. No obstant això, trobar una explicació a les variacions de CO2 entre períodes glacials i interglacials és un problema de difícil atribució. No hi ha un únic mecanisme que s'hagi identificat que expliqui tot sol les raons darrera les fluctuacions naturals totals del CO2 atmosfèric. Sembla probable que un conjunt de mecanismes hagin actuat en concert, incloent processos físics, biològics i químics, i que és probable que l'oceà hi jugui un paper important donat que és un reservori molt gran de carboni i degut a les taxes de renovació del cicle marí de carboni. El repte no és tan sols explicar l'amplitud de les variacionals glacials-interglacials de CO2, però també la complexa evolució del CO2 atmosfèric i el clima de manera consistent. Abstract Atmospheric CO2 concentrations have regularly alternated over the last 650,000 years, between fixed maxima during short interglacial periods and minima over prolonged glacial intervals. This natural variability has taken place alongside major and simultaneous changes in climatic variables, which suggests a strong causal link between climate and CO2. However, the reason for these glacial-interglacial CO2 variations remains difficult to explain. No single mechanism has been identified that accounts for the full range of natural fluctuations of atmospheric CO2. It appears likely that numerous mechanisms have acted in concert. These are likely to encompass physical, biological, and chemical processes and to involve the ocean, given its large carbon reservoir and high turnover rates. Moreover, the challenge is not only to explain the amplitude of glacial-interglacial CO2 variations, but also the complex temporal evolution of atmospheric CO2 and climate.Atmospheric CO2 concentrations have regularly alternated over the last 650,000 years, between fixed maxima during short interglacial periods and minima over prolonged glacial intervals. This natural variability has taken place alongside major and simultaneous changes in climatic variables, which suggests a strong causal link between climate and CO2. However, the reason for these glacial-interglacial CO2 variations remains difficult to explain. No single mechanism has been identified that accounts for the full range of natural fluctuations of atmospheric CO2. It appears likely that numerous mechanisms have acted in concert. These are likely to encompass physical, biological, and chemical processes and to involve the ocean, given its large carbon reservoir and high turnover rates. Moreover, the challenge is not only to explain the amplitude of glacial-interglacial CO2 variations, but also the complex temporal evolution of atmospheric CO2 and climate

Weiterentwicklung der hydrothermalen Karbonisierung zur CO2-sparenden und kosteneffizienten Trocknung von Klärschlamm im industriellen Massstab sowie der Rückgewinnung von Phosphor

In Switzerland, sewage sludge has to be burned since 2006. So far the necessary drying was done by thermal methods with high inputs of energy. In this project we investigate hydrothermal carbonisation (HTC) as CO2 saving and cost efficient alternative to dry sewage sludge on industrial scale. The focus in this applied research project is on the process water treatment, the mechanical dewatering, the potential use of HTC coal, the recycling of phosphorus and heavy metals and an assessment of environmental effects of HTC compared to current treatments. The potential for biological decomposition was investigated in HTC process water and permeat, which was gained by membrane filtration of HTC process water. A medium to high decomposition rate was shown for organic matter in HTC process water and permeat by aerobic and anaerobic processes in batch experiments. In a continuous aerobic laboratory reactor the HTC process water and permeat showed decomposition rates of 70-75% for chemical oxygen demand (COD) at a specific load of 5-10 kg COD/(m3 reactor volume*d). In the competition for a HTC-stage at the Oftringen waste water treatment plant (WWTP) an increase of dissolved organic carbon (DOC) due to the addition of HTC-permeate is limited to 3 mg/l in the effluent of the WWTP. This value can be reached by an optimised membrane filtration with no further treatment for most cases. Advantages of HTC for the mechanical dewatering were shown with a filter press on industrual scale. HTC coal was successfully burned in mono- and mixed combustion plants on industrial scale, for example at Jura Cement in Wildegg or the sludge combustion plant (SVA) in Winterthur. At SVA additional fossil fuels could be temporarily fully substituted by HTC coal. Additional experiments on industrial scale are planned. No evidence of decreased recycling capability of phosphorus or heavy metals after carbonisation was found. Compared to the currently applied sewage sludge drying process the waste heat could be reduced by up to 62% and the electricity demand by up to 69% with HTC. A detailled life cycle assessment showed little differences of HTC compared to the thermal drying process with waste heat but significant advantages compared to the thermal process of drying with fossil fuels. HTC is most promising concerning minimal environmental effects if optimizing measures are applied such as the reduction of phosphorus and nitrogen in the HTC process water, the recycling of phosphorus and the use of lost heat, renewable energy sources such as sewage gas, wood chips, green electricity on adequate sites and if the produced HTC coal is used as substitute of fossil fuels, for example in cement industry or brown coal power plants. Currently a detailled technical study is prepared by AVA-CO2 and another competitor for the first industrial HTC plant in Switzerland to dry sewage sludge at the WWTP Oftringen

Revista de Vertebrados de la Estación Biológica de Doñana

The structure of a mediterranean lizard communityDiet of the eagle owl (Bubo bubo) in mediterranean SpainTamaño de la puesta y mortalidad entre los pollos del Aguila Real ibérica (Aquila chrysaetos homeyeriDistribución y frecuencia de la cópula del buitre leonado (Gyps fulvus) en el Sur de EspañaRégimen alimenticio del calamón (Porphyrio porphyrio) en las Marismas del GuadalquivilVisible migration over the Colo Doñana, Spring 1973Diet of the Red Fox (Vulpes vulpes) in the western Sierra Morena (South Spain).Microestructura del esmalte en los incisivos de Roedores. l. Variaciones con la edadDistribution and habitat of the Barbary macaque (Macaca sylvana) in North MoroccoNotas sobre distribución de los peces fluviales en el Suroeste de España.Nuevas localidades de Valencia hispanica (Pisces:Ciprinodontidae) en el Suroeste de España.Hallazgo de Natrix mauro albinaNidificación del Phoenicopterus ruber en las Marismas del Bajo GuadalquivirNido de Aythya ferina parasitado por Fulica atraNuevos datos sobre la distribución de algunos micromamífesl ibéricos (Microtus arvalís ,M. cabrerae, M. agrestís y Sorex minutus).Neomys anomalus: Nueva localidad en el Suroeste de EspañaPeer reviewe

An interlaboratory study of TEX86 and BIT analysis using high-performance liquid chromatography–mass spectrometry

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 10 (2009): Q03012, doi:10.1029/2008GC002221.Recently, two new proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) were proposed, i.e., the TEX86 proxy for sea surface temperature reconstructions and the BIT index for reconstructing soil organic matter input to the ocean. In this study, fifteen laboratories participated in a round robin study of two sediment extracts with a range of TEX86 and BIT values to test the analytical reproducibility and repeatability in analyzing these proxies. For TEX86 the repeatability, indicating intra-laboratory variation, was 0.028 and 0.017 for the two sediment extracts or ±1–2°C when translated to temperature. The reproducibility, indicating among-laboratory variation, of TEX86 measurements was substantially higher, i.e., 0.050 and 0.067 or ±3–4°C when translated to temperature. The latter values are higher than those obtained in round robin studies of Mg/Ca and U37 k′ paleothermometers, suggesting the need to primarily improve compatibility between labs. The repeatability of BIT measurements for the sediment with substantial amounts of soil organic matter input was relatively small, 0.029, but reproducibility was large, 0.410. This large variance could not be attributed to specific equipment used or a particular data treatment. We suggest that this may be caused by the large difference in the molecular weight in the GDGTs used in the BIT index, i.e., crenarchaeol versus the branched GDGTs. Potentially, this difference gives rise to variable responses in the different mass spectrometers used. Calibration using authentic standards is needed to establish compatibility between labs performing BIT measurements

A network analysis to identify mediators of germline-driven differences in breast cancer prognosis.

Identifying the underlying genetic drivers of the heritability of breast cancer prognosis remains elusive. We adapt a network-based approach to handle underpowered complex datasets to provide new insights into the potential function of germline variants in breast cancer prognosis. This network-based analysis studies ~7.3 million variants in 84,457 breast cancer patients in relation to breast cancer survival and confirms the results on 12,381 independent patients. Aggregating the prognostic effects of genetic variants across multiple genes, we identify four gene modules associated with survival in estrogen receptor (ER)-negative and one in ER-positive disease. The modules show biological enrichment for cancer-related processes such as G-alpha signaling, circadian clock, angiogenesis, and Rho-GTPases in apoptosis

Co-variation of crenarchaeol and branched GDGTs in globally-distributed marine and freshwater sedimentary archives

Two major types of glycerol dialkyl glycerol tetraethers (GDGTs) are commonly used in paleoecological and paleoclimatological reconstructions: isoprenoidal and branched GDGTs. In aquatic environments, it was originally assumed that isoprenoidal GDGTs, especially crenarchaeol, derive mainly from aquatic Thaumarchaeota, whilst branched GDGTs are an allochthonous input derived from soil Bacteria. Recently, direct co-variation of crenarchaeol and branched GDGTs has been described in two marine sedimentary records, and this observation suggests in situ production of branched GDGTs is possible at least in some aquatic environments. After investigating 30 published and unpublished data sets from downcore and surface sediments as well as sediment traps from 19 distinct regions around the world, we found a widespread significant correlation between concentrations of branched GDGTs and crenarchaeol (p<0.01; r²=0.57-0.99), even when normalized against TOC, where available. These data sets include freshwater and marine environments with varying distances from the shore, varying redox conditions and different terrestrial matter input pathways. Our findings from this large-scale data set suggest that a common or mixed source for both GDGT types is actually commonplace in lacustrine and marine settings.Keywords: Branched GDGTs, Oceans, Crenarchaeol, Archaea, Isoprenoid GDGTs, Lakes, In situ production

Germline variants and breast cancer survival in patients with distant metastases at primary breast cancer diagnosis

Breast cancer metastasis accounts for most of the deaths from breast cancer. Identification of germline variants associated with survival in aggressive types of breast cancer may inform understanding of breast cancer progression and assist treatment. In this analysis, we studied the associations between germline variants and breast cancer survival for patients with distant metastases at primary breast cancer diagnosis. We used data from the Breast Cancer Association Consortium (BCAC) including 1062 women of European ancestry with metastatic breast cancer, 606 of whom died of breast cancer. We identified two germline variants on chromosome 1, rs138569520 and rs146023652, significantly associated with breast cancer-specific survival (P = 3.19 × 10−8 and 4.42 × 10−8). In silico analysis suggested a potential regulatory effect of the variants on the nearby target genes SDE2 and H3F3A. However, the variants showed no evidence of association in a smaller replication dataset. The validation dataset was obtained from the SNPs to Risk of Metastasis (StoRM) study and included 293 patients with metastatic primary breast cancer at diagnosis. Ultimately, larger replication studies are needed to confirm the identified associations