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131.
Rolf C. Sundt Sonnich Meier Grete Jonsson Steinar Sanni Jonny Beyer 《Marine pollution bulletin》2009,58(9):1382-1388
A biotest system for environmentally realistic exposure of fish to produced water (PW) was developed and tested. Authentic PW was collected at an oil production platform in the North Sea and preserved by freezing in multiple aliquots a 25 L. After transport to the test laboratory onshore, daily PW aliquots were thawed, homogenised and administered to the test fish, Atlantic cod (Gadus morhua), in two diluted exposure concentrations, 0.1% and 0.5%, during a 15 d period, using a continuous flow-through exposure setup. Positive control groups were exposed to two crude oil treatments for comparison. Chemical analyses showed that alkylphenol (AP) and PAH concentrations in PW exposure waters were very low. Observations of significantly increased AP and PAH metabolite levels in PW exposed fish demonstrated the suitability of the biotest system for its use in biological exposure/effect studies of PW, and it also demonstrated the sensitivity of bile metabolites as PW exposure markers in fish. The relevance of the biotest system for PW effect studies and for validating modelled environmental risk estimates of PW dischargers from offshore oil production is discussed. 相似文献
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134.
Andrea Patzer Dominik C. Hezel Verena Bendel Andreas Pack 《Meteoritics & planetary science》2018,53(7):1391-1412
We performed a LA-ICP-MS study of refractory lithophile trace elements in 32 individual objects selected from a single section of the reduced CV3 chondrite Leoville. Ingredients sampled include ferromagnesian type I and II chondrules, Al-rich chondrules (ARCs), calcium-aluminum-rich inclusions (CAIs), a single amoeboid olivine aggregate (AOA), and matrix. The majority of rare earth element (REE) signatures identified are either of the category “group II” or they are relatively flat, i.e., more or less unfractionated. Data derived for bulk Leoville exhibit characteristics of the group II pattern. The bulk REE inventory is essentially governed by those of CAIs (group II), ARCs (flat or group II), type I chondrules (about 90% flat, 10% group II), and matrix (group II). Leoville matrix also shows a superimposed positive Eu anomaly. The excess in Eu is possibly due to terrestrial weathering. The group II pattern, however, testifies to volatility-controlled fractional condensation from a residual gas of solar composition at still relatively high temperature. In principle, this signature (group II) is omnipresent in all types of constituents, suggesting that the original REE carrier of all components was CAI-like dust. In addition, single-element anomalies occasionally superimposing the group II signature reveal specific changes in redox conditions. We also determined the bulk chemical composition of all objects studied. For Mg/Si, Mg/Fe, and Al/Ca, Leoville's main ingredients—type I chondrules and matrix—display a complementary relationship. Both components probably formed successively in the same source region. 相似文献
135.
The Stubenberg meteorite—An LL6 chondrite fragmental breccia recovered soon after precise prediction of the strewn field
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Addi Bischoff Jean‐Alix Barrat Kerstin Bauer Christoph Burkhardt Henner Busemann Samuel Ebert Michael Gonsior Janina Hakenmüller Jakub Haloda Dennis Harries Dieter Heinlein Harald Hiesinger Rupert Hochleitner Viktor Hoffmann Melanie Kaliwoda Matthias Laubenstein Colin Maden Matthias M. M. Meier Andreas Morlok Andreas Pack Alexander Ruf Philippe Schmitt‐Kopplin Maria Schönbächler Robert C. J. Steele Pavel Spurný Karl Wimmer 《Meteoritics & planetary science》2017,52(8):1683-1703
136.
In recent years, the shipping of environmentally hazardous cargo has increased considerably in the Baltic proper. In this study, a large number of hypothetical oil spills with an idealized, passive tracer are simulated. From the tracer distributions, statistical measures are calculated to optimize the quantity of tracer from a spill that would stay at sea as long as possible. Increased time may permit action to be taken against the spill before the oil reaches environmentally vulnerable coastal zones. The statistical measures are used to calculate maritime routes with maximum probability that an oil spill will stay at sea as long as possible. Under these assumptions, ships should follow routes that are located south of Bornholm instead of the northern routes in use currently. Our results suggest that the location of the optimal maritime routes depends on the season, although interannual variability is too large to identify statistically significant changes. 相似文献
137.
Ferric iron reduction was studied in a pilot-scale enclosure experiment for passive biological remediation of an acidic mine pit lake in Lusatia, Germany. The metabolic properties of prokaryotes involved in Fe(III) reduction may be important for the outcome of biological remediation, as chemolithotrophic Fe(III) reduction can counteract the desired pH increase, but heterotrophic Fe(III) reduction will provide the necessary Fe(II) for precipitation of sulfide minerals following sulfate reduction. Therefore, vertical profiles of sediment parameters related to iron and sulfur cycling were determined in conjunction with viable counts of different ferric iron-reducing micro-organisms using selective media. Findings were compared to an untreated reference site. The addition of organic matter stimulated ferric iron reduction and sulfate reduction in the enclosure and led to elevated pH and accumulations of ferrous iron and reduced sulfur compounds. Numbers of neutrophilic heterotrophic Fe(III) reducers increased during treatment, those of acidophilic heterotrophic Fe(III) reducers remained similar, and those of acidophilic chemolithotrophic Fe(III) reducers decreased. Zones of ferric iron-reducing activity corresponded well with microbial depth profiles; however, viable counts of neutrophilic or acid-tolerant Fe(III) reducers must have been underestimated based on the corresponding observed activity levels. Ferric iron reduction by chemolithotrophic acidophiles seemed to be of minor importance, so a lowering of pH values due to Fe(III) reducing activity is unlikely. 相似文献
138.
I. Dimitriadis C. Papazachos D. Panagiotopoulos P. Hatzidimitriou M. Bohnhoff M. Rische T. Meier 《Journal of Volcanology and Geothermal Research》2010
One of the most prominent tectonic features of the Eastern Mediterranean region is the Hellenic volcanic arc in the Southern Aegean Sea, with the Santorini Island being one of the most active volcanic centers. Recent seismic studies show that the main seismic activity of the Santorini volcanic center is strongly associated with the volcanic processes, as well as with the seismo-tectonic regime of the broader Southern Aegean Sea area. The main cluster of local seismicity is located near the northeastern edge of the Santorini Island, beneath the Coloumbo Reef, which is a submarine volcanic seamount of the Santorini Island volcanic system. 相似文献
139.
We investigate microseismic activity at the convergent plate boundary of the Hellenic subduction zone on- and offshore south-eastern
Crete with unprecedented precision using recordings from an amphibian seismic network. The network configuration consisted
of up to eight ocean bottom seismometers as well as five temporary short-period and six permanent broadband stations on Crete
and surrounding islands. More than 2,500 local and regional events with magnitudes up to M
L = 4.5 were recorded during the time period July 2003–June 2004. The magnitude of completeness varies between 1.5 on Crete
and adjacent areas and increases to 2.5 in the vicinity of the Strabo trench 100 km south of Crete. Tests with different localization
schemes and velocity models showed that the best results were obtained from a probabilistic earthquake localization using
a 1-D velocity model and corresponding station corrections obtained by simultaneous inversion. Most of the seismic activity
is located offshore of central and eastern Crete and interpreted to be associated with the intracrustal graben system (Ptolemy
and Pliny trenches). Furthermore, a significant portion of events represents interplate seismicity along the NNE-ward dipping
plate interface. The concentration of seismicity along the Ptolemy and Pliny trenches extends from shallow depths down to
the plate interface and indicates active movement. We propose that both trenches form transtensional structures within the
Aegean plate. The Aegean continental crust between these two trenches is interpreted as a forearc sliver as it exhibits only
low microseismic activity during the observation period and little or no internal deformation. Interplate seismicity between
the Aegean and African plates forms a 100-km wide zone along dip from the Strabo trench in the south to the southern shore-line
of Crete in the north. The seismicity at the plate contact is randomly distributed and no indications for locked zones were
observed. The plate contact below and north of Crete shows no microseismic activity and seems to be decoupled. The crustal
seismicity of the Aegean plate in this area is generally confined to the upper 20 km in agreement with the idea of a ductile
deformation of the lower crust caused by a rapid return flow of metamorphic rocks that spread out below the forearc. In the
region of the Messara half-graben at the south coast of central Crete, a southward dipping seismogenic structure is found
that coalesces with the seismicity of the Ptolemy trench at a depth of about 20 km. The accretionary prism south of Crete
indicated by the Mediterranean Ridge showed no seismic activity during the observation period and seems to be deforming aseismically. 相似文献
140.
Ground-based FTIR measurements have been performed in the Arctic summer in July 1993 and June 1994 at 79° N to study the zenith column densities of several trace gases in the undisturbed Arctic summer atmosphere. Zenith column densities of H2O, N2O, HNO3, NO2, NO, ClONO2, ClO, HCl, HF, COF2, OCS, SF6, HCN, CH4, C2H6, C2H2, CO, O3, CFC-12, CFC-22, and CO2 were retrieved by line-by-line calculations. The results are compared with winter and springtime observations measured at the same site, with column densities obtained in the Antarctic summer atmosphere, and with measurements at midlatitudes. For HCl the spectra give lower total zenith columns than expected, but the ratio HF/HCl agrees well with midlatitude literature data. Measurements of ClONO2 give low total columns in agreement with observations at midlatitudes. In the undisturbed atmosphere HCl was found to be in excess of ClONO2. The total columns of HNO3, N2O and the sum of NO and NO2 agree with summer observations in Antarctica. Results for the tropospheric trace gas C2H6 are higher by 250% when compared with Antarctic observations. Contrary to N2O and CH4 the seasonal cycle of C2H6 and C2H2 give much higher total columns in winter/spring compared to the summer observations. This is assigned to transport of polluted airmasses from mid-latitudes into the Arctic. 相似文献