TY  - JOUR
AB  - The geological materials produced during catastrophic and destructive events are an essential source of paleobiological knowledge. The paleobiological information recorded by such events can be rich in information on the size, diversity, and structure of paleocommunities. In this regard, the geobiological study of late Devonian organic matter sampled in Tharsis (Iberian Pyrite Belt) provided some new insights into a Paleozoic woodland community, which was recorded as massive sulfides and black shale deposits affected by a catastrophic event. Sample analysis using TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometer), and complemented by GC/MS (Gas Chromatrograph/Mass Spectrometer) identified organic compounds showing a very distinct distribution in the rock. While phytochemical compounds occur homogeneously in the sample matrix that is composed of black shale, the microbial-derived organics are more abundant in the sulfide nodules. The cooccurrence of sulfur bacteria compounds and the overwhelming presence of phytochemicals provide support for the hypothesis that the formation of the massive sulfides resulted from a high rate of vegetal debris production and its oxidation through sulfate reduction under suboxic to anoxic conditions. A continuous supply of iron from hydrothermal activity coupled with microbial activity was strictly necessary to produce this massive orebody. A rough estimate of the woodland biomass was made possible by accounting for the microbial sulfur production activity recorded in the metallic sulfide. As a result, the biomass size of the late Devonian woodland community was comparable to modern woodlands like the Amazon or Congo rainforests.
AU  - Fernández-Remolar, D.C.*
AU  - Harir, M.
AU  - Carrizo, D.*
AU  - Schmitt-Kopplin, P.
AU  - Amils, R.*
C1  - 53347
C2  - 44685
SP  - 1017-1040
TI  - Productivity contribution of paleozoic woodlands to the formation of shale-hosted massive sulfide deposits in the Iberian Pyrite Belt (Tharsis, Spain).
JO  - J. Geophys. Res.
VL  - 123
IS  - 3
PY  - 2018
SN  - 0022-1406
ER  - 

TY  - JOUR
AB  - Similarities between the Atacama Desert (Chile) and Mars include extreme aridity, highly oxidizing chemistry, and intense ultraviolet radiation that promoted the photochemical production of perchlorates and nitrates. Concentration of these ions under hyperarid conditions led to the formation of nitrate- and perchlorate-bearing deposits in ephemeral lakes, followed by later deposition of chlorides and sulfates. At some locations, such as the Salar Grande, hypersaline deposits have remained unaltered for millions of years. We conducted a drilling campaign in deposits of the Salar to characterize the preservation state of biological molecules. A 5 m deep discontinuous core was recovered and subjected to multitechnique analysis including the antibody microarray-based biosensor LDChip300 and the SOLID (Signs Of Life Detector) instrument, complemented by geophysical, mineralogical, geochemical, and molecular analysis. We identified two units based on the mineralogy: the upper one, from the surface to ~320 cm depth characterized by a predominance of halite and anhydrite, and the lower one, from 320 to 520 cm, with a drop in halite and anhydrite and an enrichment in nitrate and perchlorate. Organic compounds including biomolecules were detected in association with the different depositional and mineralogical units, demonstrating the high capacity for molecular preservation. Hypersaline environments preserve biomolecules over geologically significant timescales; therefore, salt-bearing materials should be high-priority targets for the search for evidence of life on Mars. Key PointsPreservation of biomolecules in salty deposits of AtacamaSame salty deposits are found in MarsMars salt-enriched deposits have a great astrobiological potential.
AU  - Fernández-Remolar, D.C.*
AU  - Chong-Diaz, G.*
AU  - Ruiz-Bermejo, M.*
AU  - Harir, M.
AU  - Schmitt-Kopplin, P.
AU  - Tziotis, D.
AU  - Gomez-Ortiz, D.*
AU  - Garcia-Villadangos, M.*
AU  - Martin-Redondo, M.P.*
AU  - Gomez, F.*
AU  - Rodriguez-Manfredi, J.A.*
AU  - Moreno-Paz, M.*
AU  - de Diego-Castilla, G.*
AU  - Echeverria, A.*
AU  - Urtuvia, V.N.*
AU  - Blanco, Y.*
AU  - Rivas, L.*
AU  - Izawa, M.R.M.*
AU  - Banerjee, N.R.*
AU  - Demergasso, C.*
AU  - Parro, V.*
C1  - 26027
C2  - 32029
SP  - 922-939
TI  - Molecular preservation in halite- and perchlorate-rich hypersaline subsurface deposits in the Salar Grande basin (Atacama Desert, Chile): Implications for the search for molecular biomarkers on Mars.
JO  - J. Geophys. Res.
VL  - 118
IS  - 2
PB  - Amer. Geophysical Union
PY  - 2013
SN  - 0022-1406
ER  - 

TY  - JOUR
AB  - A leaf stomatal conductance model was combined with a hydrological tree and soil water flow model and a spatially explicit three-dimensional canopy light model. The model was applied to single, old-growth Fagus sylvatica L. trees, and the measured daily values of stem sap flux could be reproduced with a normalized root mean square error of 0.10 for an observation period of 32 days in the summer of 2009. The high temporal resolution of the model also makes it possible to simulate the diurnal dynamics of transpiration, stem sap flux, and root water uptake. We applied new data-processing algorithms to information from terrestrial laser scans to represent the canopies of the functional-structural model. The high spatial resolution of the root and branch geometry and connectivity makes the detailed modeling of the water usage of single trees possible and allows for the analysis of the interaction between single trees and the influence of the canopy light regime on the water flow inside the xylem. In addition to the laser scans of the observed trees, the model needs tree-species-specific physiological input parameters, which are easy to obtain. The model can be applied at various sites and to different tree species, allowing the up-scaling of the water usage of single trees to the total transpiration of mixed stands.
AU  - Bittner, S.
AU  - Legner, N.*
AU  - Beese, F.*
AU  - Priesack, E.
C1  - 7406
C2  - 29702
TI  - Individual tree branch-level simulation of light attenuation and water flow of three F. sylvatica L. trees.
JO  - J. Geophys. Res.
VL  - 117
IS  - 1
PB  - American Geophysical Union
PY  - 2012
SN  - 0022-1406
ER  - 

TY  - JOUR
AB  - Two Bonner Sphere Spectrometers (BSS) were used - one at the Schneefernerhaus, Germany (altitude: 2650 m; geomagnetic cut-off: 4.1 GV), the other at the Koldewey station on Spitsbergen (sea level; geomagnetic: cut-off 0 GV) - to measure continuously the spectral flux distribution of secondary neutrons from cosmic radiation. At the Schneefernerhaus, the flux of thermal neutrons was about 75% higher in summer than in winter, that of epithermal neutrons about 80%, that of neutrons between 0.125 and 17.8 MeV about 32%, and that of neutrons above 17.8 MeV about 4%, respectively. The period of the observed oscillations was very close to one year. Similar oscillations were observed at the Koldewey station, with somewhat smaller amplitudes (40%, 45%, 22%, and 2%, respectively). At both stations, the flux of the neutrons above 17.8 MeV increased with time similar to the count rates measured by nearby neutron monitors. While this increase reflects changes in the Sun's activity, the observed oscillations are due to changes in ground albedo neutrons and their absorption due to snow. Consequently, the monthly averaged neutron ambient dose equivalent rates, H*(10), oscillated by about +/- 7% at the UFS and about +/- 4% at the Koldewey Station. The results demonstrate that BSS measurements could be used to monitor secondary neutrons from cosmic radiation above about 20 MeV. Below detailed neutron transport calculations are necessary to correct for changes in ground albedo neutrons and snow cover. The data presented here can be used as an experimental basis to perform such simulations.
AU  - Rühm, W.
AU  - Ackermann, U.
AU  - Pioch, C.
AU  - Mares, V.
C1  - 8535
C2  - 30377
TI  - Spectral neutron flux oscillations of cosmic radiation on the Earth's surface.
JO  - J. Geophys. Res.
VL  - 117
IS  - 8
PB  - Amer. Geophysical Union
PY  - 2012
SN  - 0022-1406
ER  - 

TY  - JOUR
AB  - Ground-based measurements of aerosol optical properties were conducted during Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006) (11 August to 9 September 2006) at a suburban site similar to 30 km south of Beijing. Averaged over the measurement campaign (arithmetic mean +/- standard deviation), the total scattering coefficients (sigma(s)) were 469 +/- 374 Mm(-1) (450 nm), 361 +/- 295 Mm(-1) (550 nm), and 249 +/- 206 Mm(-1) (700 nm) and the absorption coefficient (sigma(a)) was 51.8 +/- 36.5 Mm(-1) (532 nm). The average Angstrom exponent was 1.42 +/- 0.19 (450 nm/700 nm) and the average single scattering albedo (w(532)) was 0.86 +/- 0.07 (532 nm) with minimum values as low as 0.5. Pronounced diurnal cycles were observed in sigma(s), sigma(a), and w(532) and can be explained by boundary layer mixing effects. Additionally, an enhancement of absorbing particles in the early morning (0500- 0800 local time) was observed; this may be attributed to soot emissions from traffic activity. When the measured air masses originated in the north and passed over Beijing, the single scattering albedo was generally low (w(532) < 0.8), which indicates that the local emissions of particulate matter in Beijing were dominated by primary particles from combustion sources (soot). The southerly inflow to Beijing had typically very high sigma(s) and higher than average w(532) values, suggesting a large amount of secondary aerosol (e. g., sulfate and oxidized organics). Overall, the results suggest that a majority of the particle pollution in Beijing is transported into the city from the south.
AU  - Garland, R.M.*
AU  - Schmid, O.
AU  - Nowak, A.*
AU  - Achtert, P.*
AU  - Wiedensohler, A.*
AU  - Gunthe, S.S.*
AU  - Takegawa, N.*
AU  - Kita, K.*
AU  - Kondo, Y.*
AU  - Hu, M.*
AU  - Shao, M.*
AU  - Zeng, L.M.*
AU  - Zhu, T.*
AU  - Andreae, M.O.*
AU  - Pöschl, U.*
C1  - 1607
C2  - 26400
TI  - Aerosol optical properties observed during Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006: Characteristic differences between the inflow and outflow of Beijing city air.
JO  - J. Geophys. Res.
VL  - 114
IS  - 3
PB  - Amer Geophysical Union
PY  - 2009
SN  - 0022-1406
ER  - 

TY  - JOUR
AB  - [1] Annual fluxes of N2O trace gas emissions were assessed after stratifying German forest soils into Seasonal Emission Pattern (SEP) and Background Emission Pattern (BEP). Broad-leaved forests with soil pH(KCl) ≤ 3.3 were assigned to have SEP, broad-leaved forests with soil pH(KCl) > 3.3 and all needle-leaved forests to have BEP. BEPs were estimated by a relationship between annual N2O emissions and carbon content of the O-horizon. SEPs were primarily controlled by temperature and moisture and simulated by the model Expert-N after calibration to a 9-year record of N2O measurements. Analysis with different climate and soil properties indicated that the model reacts highly sensitive to changes in soil temperature, soil moisture, and soil texture. A geographic information system (ARC/INFO) was used for a spatial resolution of 1 km × 1 km grid where land cover, dominant soil units, and hygro climate classes were combined. The mean annual N2O emission flux from German forest soils was estimated as 0.32 kg ha−1 yr−1. Broad-leaved forests with SEP had the highest emissions (2.05 kg ha−1 yr−1) followed by mixed forests (0.38 kg ha−1 yr−1), broad-leaved forests (0.37 kg ha−1 yr−1), and needle-leaved forests with BEP (0.17 kg ha−1 yr−1). The annual N2O emission from German forest soils was calculated as 3.26 Gg N2O-N yr−1. Although needle-leaved trees cover about 57% of the entire forest area in Germany, their contribution is low (0.96 Gg N2O-N yr−1). Broad-leaved forests cover about 22% of the forest area but have 55% higher emissions (1.49 Gg N2O-N yr−1) than needle-leaved. Mixed forests cover 21% of the area and contribute 0.81 Gg N2O-N yr−1. Compared to the total N2O emissions in Germany of 170 Gg N yr−1, forest soils contribute only 1.9%. However, there are some uncertainties in this emission inventory, which are intensely discussed.
AU  - Schulte-Bisping, H.*
AU  - Brumme, R.*
AU  - Priesack, E.
C1  - 22158
C2  - 20853
SP  - 1-9
TI  - Nitrous oxide emission inventory of German forest soils.
JO  - J. Geophys. Res.
VL  - 108
IS  - D4
PY  - 2003
SN  - 0022-1406
ER  -