87 research outputs found
CO2 soil flux baseline at the technological development plant for CO2 injection at Hontomin (Burgos, Spain)
From the end of 2013 and during the following two years, 20 kt of CO2sc are planned to be injected in a saline reservoir (1500 m depth) at the HontomĂn site (NE Spain). The target aquifers are Lower Jurassic limestone formations which are sealed by Lower Cretaceous clay units at the HontomĂn site (NE Spain). The injection of CO2 is part of the activities committed in the Technology Development phase of the EC-funded OXYCFB300 project (European Energy Program for Recovery â EEPR, http://www.compostillaproject.eu), which include CO2 injection strategies, risk assessment, and testing and validating monitoring methodologies and techniques.
Among the monitoring works, the project is intended to prove that present-day technology is able to monitor the evolution of injected CO2 in the reservoir and to detect potential leakage. One of the techniques is the measurement of CO2 flux at the soilâatmosphere interface, which includes campaigns before, during and after the injection operations.
In this work soil CO2 flux measurements in the vicinity of oil borehole, drilled in the eighties and named H-1 to H-4, and injection and monitoring wells were performed using an accumulation chamber equipped with an IR sensor. Seven surveys were carried out from November 2009 to summer 2011. More than 4000 measurements were used to determine the baseline flux of CO2 and its seasonal variations.
The measured values were low (from 5 to 13 g mâ2 dayâ1) and few outliers were identified, mainly located close to the H-2 oil well. Nevertheless, these values cannot be associated to a deep source of CO2, being more likely related to biological processes, i.e. soil respiration. No anomalies were recognized close to the deep fault system (Ubierna Fault) detected by geophysical investigations. There, the CO2 flux is indeed as low as other measurement stations. CO2 fluxes appear to be controlled by the biological activity since the lowest values were recorded during autumn-winter seasons and they tend to increase in warm periods. Two reference CO2 flux values (UCL50 of 5 g mâ2 dâ1 for non-ploughed areas in autumnâwinter seasons and 3.5 and 12 g mâ2 dâ1 for in ploughed and non-ploughed areas, respectively, in springâsummer time, and UCL99 of 26 g mâ2 dâ1 for autumnâwinter in not-ploughed areas and 34 and 42 g mâ2 dâ1 for springâsummer in ploughed and not-ploughed areas, respectively) were calculated. Fluxes higher than these reference values could be indicative of possible leakage during the operational and post-closure stages of the storage project
Tracking down carbon inputs underground from an arid zone Australian calcrete.
Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (ÎŽ13CDOC, ÎŽ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota
Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the LĂłpez de Bertodano Formation, Seymour Island, Antarctica
One of the most expanded records to contain the final fortunes of ammonoid cephalopods is within the López de Bertodano Formation of Seymour Island, James Ross Basin, Antarctica. Located at 65° South now, and during the Cretaceous, this sequence is the highest southern latitude onshore outcrop containing the Cretaceous-Paleogene (K-Pg) transition. We present comprehensive new biostratigraphic range data for 14 ammonite and one nautiloid species based on the collection of >. 700 macrofossils from high-resolution sampling of parallel sedimentary sections, dated Maastrichtian to earliest Danian in age, across southern Seymour Island. We find evidence for only a single, abrupt pulse of cephalopod extinction at the end of the Cretaceous when the final seven ammonite species disappeared, consistent with most evidence globally. In the lead up to the K-Pg extinction in the James Ross Basin, starting during the Campanian, ammonite diversity decreased overall, but the number of endemic taxa belonging to the family Kossmaticeratidae actually increased. This pattern continued into the Maastrichtian and may be facies controlled, linked to changes in sea level and seawater temperature. During the early Maastrichtian, ammonite diversity dropped significantly with only two species recorded from the basal López de Bertodano Formation on Seymour Island. The subsequent diversification of endemic taxa and reappearance of long-ranging, widespread species into the basin resulted in an increase in ammonite diversity and abundance during the mid-Maastrichtian. This was coincident with an apparent period of warming temperatures and sea level rise interpreted from palynology and sedimentology, perhaps reflecting a high latitude expression of the Mid-Maastrichtian Event. Late Maastrichtian diversity levels remained stable despite reported climatic and environmental variation. Ammonite diversity patterns during the Maastrichtian parallel those of microfossil species such as nannofossil and planktonic foraminifera, suggesting that dynamic climatic and environmental changes affected many planktonic and nektonic organisms during the latest Cretaceous. However, we suggest that these perturbations had a minimal effect on overall diversity prior to the catastrophic extinction event at the K-Pg boundary
Astronomical calibration of the Danian Stage (Early Paleocene) revisited: settling chronologies across the Atlantic and Pacific Oceans
The astronomical time scale for the Paleocene is hampered
by some uncertainties including discrepant number of 405-kyr
eccentricity related cycles and correlation schemes among key
records being proposed by different authors (Westerhold et al.,
2008; Kuiper et al., 2008; Hilgen et al., 2010). Here we present
a new Danian correlation framework resolved at the ~100-kyr
short-eccentricity level between the land-based Zumaia and
Sopelana hemipelagic sections from the Basque Basin and
deep-sea records drilled during ODP Legs 198 (Shatsky Rise,
North Pacific) and 208 (Walvis Ridge, South Atlantic) that
reconciles both the magnetostratigraphy and the short and longeccentricity
cycle patterns among the records and, hence,
improves synchroneity of events. The correlation has been
aided by composite images from ODP cores and a new wholerock
13C isotope record at Zumaia while its original
magnetostratigraphy (DinarĂšs-Turell et al., 2003; 2010) is
reinforced by new data from Sopelana. Notably, we challenge
the correlation of the Pacific Sites 1209â1210 that were offset
by as much as one 405-kyr cycle in previous interpretations
(i.e., the Fasciculithus spp. LO, which approximates the
DanianâSelandian (DâS) boundary, and the âTop chron C27nâ
climatic event were at odds between oceans in the
interpretation of Hilgen et al. (2010). It is found that the
Danian consists of 11 (and not 10) consecutive 405-kyr
eccentricity cycles.
The new consistent stratigraphic framework enables
accurate estimates to be made of ages for magnetostratigraphic
boundaries, bioevents, and sedimentation rates. Low
sedimentation rates appear common in all records in the mid-
Danian interval along the upper part of chron C28n, including
conspicuous condensed intervals in some of the oceanic
records that in the past have hampered the proper identification
of cycles. The new chronological framework, spanning a
duration of about 4.5 My, allows assessing the role of orbital
forcing on the paleoclimatic variability as registered by the
related isotope records. It appears clear that there exists a
periodic beat at the 100-ky and 405-ky eccentricity cycles
impressed in the record. The phase relationship between the
benthic isotope record and eccentricity is similar to patterns
documented for the Oligocene and Miocene, as indicated by
others, confirming the role of orbital forcing as the pace maker
for paleoclimatic variability on Milankovitch time scales. The
preferred tuning to the La2011 orbital solution provides
astronomically calibrated ages of 66.022±0.040 Ma and
61.607±0.040 Ma for the (DâS) and CretaceousâPaleogene
(KâPg) boundaries respectively. Finally, we envisage that the
Zumaia section, which already hosts the Selandian GSSP,
could serve as the global Danian stratotype.Published64-651A. Geomagnetismo e PaleomagnetismoN/A or not JCRrestricte
Astronomical calibration of the Danian Stage (Early Paleocene) revisited: settling chronologies across the Atlantic and Pacific Oceans
The astronomical time scale for the Paleocene is hampered
by some uncertainties including discrepant number of 405-kyr
eccentricity related cycles and correlation schemes among key
records being proposed by different authors (Westerhold et al.,
2008; Kuiper et al., 2008; Hilgen et al., 2010). Here we present
a new Danian correlation framework resolved at the ~100-kyr
short-eccentricity level between the land-based Zumaia and
Sopelana hemipelagic sections from the Basque Basin and
deep-sea records drilled during ODP Legs 198 (Shatsky Rise,
North Pacific) and 208 (Walvis Ridge, South Atlantic) that
reconciles both the magnetostratigraphy and the short and longeccentricity
cycle patterns among the records and, hence,
improves synchroneity of events. The correlation has been
aided by composite images from ODP cores and a new wholerock
ï€13C isotope record at Zumaia while its original
magnetostratigraphy (DinarĂšs-Turell et al., 2003; 2010) is
reinforced by new data from Sopelana. Notably, we challenge
the correlation of the Pacific Sites 1209â1210 that were offset
by as much as one 405-kyr cycle in previous interpretations
(i.e., the Fasciculithus spp. LO, which approximates the
DanianâSelandian (DâS) boundary, and the âTop chron C27nâ
climatic event were at odds between oceans in the
interpretation of Hilgen et al. (2010). It is found that the
Danian consists of 11 (and not 10) consecutive 405-kyr
eccentricity cycles.
The new consistent stratigraphic framework enables
accurate estimates to be made of ages for magnetostratigraphic
boundaries, bioevents, and sedimentation rates. Low
sedimentation rates appear common in all records in the mid-
Danian interval along the upper part of chron C28n, including
conspicuous condensed intervals in some of the oceanic
records that in the past have hampered the proper identification
of cycles. The new chronological framework, spanning a
duration of about 4.5 My, allows assessing the role of orbital
forcing on the paleoclimatic variability as registered by the
related isotope records. It appears clear that there exists a
periodic beat at the 100-ky and 405-ky eccentricity cycles
impressed in the record. The phase relationship between the
benthic isotope record and eccentricity is similar to patterns
documented for the Oligocene and Miocene, as indicated by
others, confirming the role of orbital forcing as the pace maker
for paleoclimatic variability on Milankovitch time scales. The
preferred tuning to the La2011 orbital solution provides
astronomically calibrated ages of 66.022±0.040 Ma and
61.607±0.040 Ma for the (DâS) and CretaceousâPaleogene
(KâPg) boundaries respectively. Finally, we envisage that the
Zumaia section, which already hosts the Selandian GSSP,
could serve as the global Danian stratotype
Settling the Danian Astronomical Time Scale: A Prospective Global Unit Stratotype at Zumaia, Basque Basin
We present a new Danian correlation framework between the land-based
Zumaia and Sopelana sections from the Basque Basin and marine-based sections
drilled during ODP Legs 198 (Shatsky Rise, North Pacific) and 208 (Walvis Ridge,
South Atlantic) that reconciles magnetostratigraphy and the short and long eccentricity
cycle patterns among the records. A new whole-rock d13C isotope record at
Zumaia is compared to that of Site 1262. This allows the question of whether the
Danian consists of 10 or 11 consecutive 405-kyr eccentricity cycles to be tested. The
new consistent stratigraphic framework enables accurate estimates to be made of
ages for magnetostratigraphic boundaries, bioevents, and sedimentation rates. Low
sedimentation rates appear common in all records in the mid-Danian interval along
the upper part of chron C28n, including conspicuous condensed intervals in some of
the oceanic records that in the past have hampered the proper identification of
cycles. Notably, we challenge the correlation to the Pacific Sites 1209â1210 that
were offset by as much as one 405-kyr cycle in previous interpretations (i.e., the
Fasciculithus spp. LO, which approximates the DanianâSelandian boundary, and
the TC27n event were at odds between oceans in the interpretation of Hilgen et al.
2010). Finally, we envisage that the Zumaia section, which already hosts the
Selandian GSSP, could serve as the global Danian stratotype
Description of Enterovibrio nigricans sp. nov., reclassification of Vibrio calviensis as Enterovibrio calviensis comb. nov. and emended description of the genus Enterovibrio Thompson et al. 2002
Disseminated herpes zoster with cauda equina symptoms
Herpes zoster is a common infection resulting from the reactivation of dormant varicella zoster virus in a posterior dorsal root ganglion. The typical dermatomal involvement includes the thoracic region, followed by the face and the cervical and lumbosacral regions, with 1% having disseminated disease. We present a rare case of an immunocompetent 85-year-old man presenting with herpes zoster at the L3-S2 dermatomes, that evolved to disseminated varicella zoster virus (dVZV), with radiologically and laboratory-confirmed lumbosacral plexopathy manifesting with cauda equina syndrome. Here we also discuss the diagnosis and complications of dVZV as well as treatment strategy. By maintaining a high degree of clinical suspicion and initiating early treatment, high-quality patient care and good outcomes are able to be achieved in cases like this
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