Contaminant exposure and effects in Baltic ringed and grey seals as assessed by biomarkers

The Baltic Sea ecosystem has suffered from a heavy pollutant load for more than three decades. Persistent organic pollutants (POPs) and heavy metals have been of most concern due to their persistence and toxic properties. Ringed seals (Phoca hispida baltica) and grey seals (Halichoerus grypus) living in the Baltic Sea have been suffering from pathological impairments, including reproductive disturbances, which have resulted in a depressed reproductive capacity. We investigated several biochemical parameters as potential biomarkers for exposure to and effects of the contaminant load in the Baltic seals. Seals from less polluted areas were used as reference material in terms of the pollution load. In both Baltic seal populations, the levels of some biochemical parameters diverged from those in the reference seals, and some of these showed a clear correlation with the individual contaminant load. Of the potential bioindicators, we propose cytochrome P4501A activity and vitamin E levels, in blubber or plasma, as exposure biomarkers for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in both species. The arylhydrocarbon receptor-mediated chemical-activated luciferase gene expression (CALUX) response reflects the whole PCB and DDT burden in ringed seals. Retinyl palmitate (vitamin A) levels showed a negative correlation with the individual POP load, and is proposed as potential effect biomarkers for the depletion of the vitamin A stores. As the nutritional levels of both vitamin A and E have an impact on the vitamin levels in the seals, more information on the dietary vitamin levels is needed before any conclusions can be drawn. As the relationship between biochemical parameters and contaminants varied between the two species, species-specific characteristics has to be considered when monitoring the health status and possible toxic effects of the contaminant load in ringed and grey seals.     

The dependence of organohalogen compound concentrations on herring age and size in the Bothnian Sea, northern Baltic

The concentrations and composition profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers and polychlorinated naphthalenes were determined in herring individuals collected from the commercial catches of the Bothnian Sea, northern Baltic. The median age of herring was 5.0 years and in the muscle the median toxic equivalent concentration of PCDD/Fs was 5.6 WHO(PCDD/F)-TEQ pg/g fresh weight (fw) and that of PCBs 2.7 WHO(PCB)-TEQ pg/g fw. The median sum concentration of PBDEs was 1.4 ng/g fw and that of PCNs 0.1 ng/g fw. Differences in age-dependent accumulation between the organohalogen groups and individual congeners were major. In the Bothnian Sea the content of organohalogen compounds in herring is obviously elevated due to the availability and large proportion of Mysis crustaceans in their diet. More intensive fishing could reduce the concentrations of organohalogens, including the abundant, accumulative and toxic 2,3,4,7,8-PeCDF congener in the Baltic herring catch.     

Hosts of hydrogen in Allan Hills 84001: Evidence for hydrous martian salts in the oldest martian meteorite?

Abstract— The martian meteorite, Allan Hills (ALH) 84001, contains D‐rich hydrogen of plausible martian origin (Leshin et al., 1996). The phase identity of the host(s) of this hydrogen are not well known and could include organic matter (McKay et al., 1996), phlogopite (Brearley, 2000), glass (Mittlefehldt, 1994) and/or other unidentified components of this rock. Previous ion microprobe studies indicate that much of the hydrogen in ALH 84001 as texturally associated with concretions of nominally anhydrous carbonates, glass and oxides (Boctor et al., 1998; Sugiura and Hoshino, 2000). We examined the physical and chemical properties of the host(s) of this hydrogen by stepped pyrolysis of variously pre‐treated subsamples. A continuous‐flow method of water reduction and mass spectrometry (Eiler and Kitchen, 2001) was used to permit detailed study of the small amounts of this hydrogen‐poor sample available for study. We find that the host(s) of D‐rich hydrogen released from ALH 84001 at relatively low temperatures (?500 °C) is soluble in orthophosphoric and dilute hydrochloric acids and undergoes near‐complete isotopic exchange with water within hours at temperatures of 200 to 300 °C. These characteristics are most consistent with the carrier phase(s) being a hydrous salt (e.g., carbonate, sulfate or halide); the thermal stability of this material is inconsistent with many examples of such minerals (e.g., gypsum) and instead suggests one or more relatively refractory hydrous carbonates (e.g., hydromagnesite). Hydrous salts (particularly hydrous carbonates) are common on the Earth only in evaporite, sabkha, and hydrocryogenic‐weathering environments; we suggest that much (if not all) of the “martian” hydrogen in ALH 84001 was introduced in analogous environments on or near the martian surface rather than through biological activity or hydrothermal alteration of silicates in the crust.     

Shock experiments in range of 10–45 GPa with small multidomain magnetite in porous targets

Abstract– Physical properties of multidomain magnetite‐bearing porous pellets shocked up to 45 GPa were measured. The results show general magnetic softening as a result of shock. However, a relative magnetic hardening trend and slight magnetic susceptibility decrease is observed with increasing pressure among shocked samples. Initially, the shock also seems to cause a slight decrease in porosity, but at higher shock pressures macroscopic porosity increases progressively in our pellets. The microscopic porosity remains almost unchanged. Since our samples have distinctly higher initial porosity compared with samples used in previous studies, our results may be representative for impacts into highly porous magnetite‐bearing sedimentary or volcanic rocks and are relevant to impacts into such target rocks on Earth and Mars.     

Magnetic classification of stony meteorites: 2. Non‐ordinary chondrites

Abstract— A database of magnetic susceptibility (χ) measurements on different non‐ordinary chondrites (C, E, R, and ungrouped) populations is presented and compared to our previous similar work on ordinary chondrites. It provides an exhaustive study of the amount of iron‐nickel magnetic phases (essentially metal and magnetite) in these meteorites. In contrast with all the other classes, CM and CV show a wide range of magnetic mineral content, with a two orders of magnitude variation of χ. Whether this is due to primary parent body differences, metamorphism or alteration, remains unclear. C3–4 and C2 yield similar χ values to the ones shown by CK and CM, respectively. By order of increasing χ, the classes with well‐grouped χ are: R << CO < CK ≈ CI < Kak < CR < E ≈ CH < CB. Based on magnetism, EH and EL classes have indistinguishable metal content. Outliers that we suggest may need to have their classifications reconsidered are Acfer 202 (CO), Elephant Moraine (EET) 96026 (C4–5), Meteorite Hills (MET) 01149, and Northwest Africa (NWA) 521 (CK), Asuka (A)‐88198, LaPaz Icefield (LAP) 031156, and Sahara 98248 (R). χ values can also be used to define affinities of ungrouped chondrites, and propose pairing, particularly in the case of CM and CV meteorites.     

Cross-Calibration of SMART-1 XSM with GOES and RHESSI

A number of X-ray instruments have been active in observing the solar coronal X-ray radiation this decade. We have compared XSM observations with simultaneous GOES and RHESSI observations. We present flux calibrations for all instruments and compare XSM and GOES total emission measures (TEM) and temperatures (T).     

The Keurusselkä impact structure,Finland—Impact origin confirmed by characterization of planar deformation features in quartz grains

Abstract– Although the meteorite impact origin of the Keurusselkä impact structure (central Finland) has been established on the basis of the occurrence of shatter cones, no detailed microscopic examination of the impactites from this structure has so far been made. Previous microscope investigations of in situ rocks did not yield any firm evidence of shock features (Raiskila et al. 2008; Kinnunen and Hietala 2009). We have carried out microscopic observations on petrographic thin sections from seven in situ shatter cone samples and report here the discovery of planar fractures (PFs) and planar deformation features (PDFs) in quartz and feldspar grains. The detection and characterization of microscopic shock metamorphic features in the investigated samples substantiates a meteorite impact origin for the Keurusselkä structure. The crystallographic orientations of 372 PDF sets in 276 quartz grains were measured, using a universal stage (U‐stage) microscope, for five of the seven distinct shatter cone samples. Based on our U‐stage results, we estimate that investigated shatter cone samples from the Keurusselkä structure have experienced peak shock pressures from approximately 2 GPa to slightly less than 20 GPa for the more heavily shocked samples. The decoration of most of the PDFs with fluid inclusions also indicates that these originally amorphous shock features were altered by postimpact processes. Finally, our field observations indicate that the exposed surface corresponds to the crater floor; it is, however, difficult to estimate the exact diameter of the structure and the precise amount of material that has been eroded since its formation.     

Magnetic properties of asteroids from meteorite data — Implications for magnetic anomaly detections

Magnetic measurements of meteorites suggest that small bodies (e.g. asteroids) in the Solar System have small but distinct magnetic fields produced by the bulk remanent magnetisation (NRM) of the body. Here we report calculations of magnetic fields of small bodies, assuming that they can be approximated as homogeneously magnetised spheres with dipole moments derived from NRM data on known meteorites. The magnetic fields are compared with the field of the asteroid 951 Gaspra measured by spacecraft Galileo in 1991 (Kivelson et al., 1993). The result of this comparison suggests that the field of Gaspra could be caused by an L-, H- or E-chondritic or a pallasite body. The spectral reflectance data on Gaspra suggest, however, that it is a basaltic achondrite. The problem can be resolved if Gaspra is a differentiated body, its surface material being closer to that of basaltic achondrites, and the bulk closer to ordinary chondrites or pallasites. We also present magnetic anomaly profiles along the surface of Mars such as would be measured with a magnetometer installed on a Rover-type vehicle by assuming that the main sources of the surface anomalies are the NRMs of the boulders on the Martian surface. The NRM values are taken from the data measured on SNC meteorites. The results suggest large oscillations in magnetic field intensity at the Martian surface.     

Terrestrial impact craters: Their spatial and temporal distribution and impacting bodies

The terrestrial impact record contains currently ~145 structures and includes the morphological crater types observed on the other terrestrial planets. It has, however, been severely modified by terrestrial geologic processes and is biased towards young (≤ 200 Ma) and large (≥ 20 km) impact structures on relatively well-studied cratonic areas. Nevertheless, the ground-truth data available from terrestrial impact structures have provided important constraints for the current understanding of cratering processes. If the known sample of impact structures is restricted to a subsample in which it is believed that all structures ≥ 20 km in diameter (D) have been discovered, the estimated terrestrial cratering rate is 5.5±2.7 × 10^?15km^?2a^?1 for D ≥ 20 km. This rate estimate is equivalent to that based on astronomical observations of Earth-crossing bodies. These rates are a factor of two higher, however, than the estimated post-mare cratering rate on the moon but the large uncertainties preclude definitive conclusions as to the significance of this observation. Statements regarding a periodicity in the terrestrial cratering record based on time-series analyses of crater ages are considered unjustified, based on statistical arguments and the large uncertainties attached to many crater age estimates. Trace element and isotopic analyses of generally siderophile group elements in impact lithologies, particularly impact melt rocks, have provided the basis for the identification of impacting body compositions at a number of structures. These range from meteoritic class, e.g., C-1 chondrite, to tentative identifications, e.g., stone?, depending on the quality and quantity of analytical data. The majority of the identifications indicate chondritic impacting bodies, particularly with respect to the larger impact structures. This may indicate an increasing role for cometary impacts at larger diameters; although, the data base is limited and some identifications are equivocal. To realize the full potential of the terrestrial impact record to constrain the character of the impact flux, it will be necessary to undertake additional and systematic isotopic and trace element analyses of impact lithologies at well-characterized terrestrial impact structures.     

Model computations on the effect of rising temperature on soil moisture and water availability in forest ecosystems dominated by scots pine in the boreal zone in Finland

Based on model calculations, the moisture of soil for sites with and without a cover of trees under the current and rising temperature was studied assuming a 5 °C increase in annual mean temperature over a period of 100 years. The calculation for southern Finland (61°N) showed that the soil moisture under elevated temperature could be reduced compared to that under current temperature conditions. This was also true for northern Finland (66°N), but there the reduction in soil moisture was less substantial. In particular, when trees were present, the soil moisture during the growing season was reduced due to enhanced evapotranspiration. In the presence of trees, the moisture content of the surface soil was only half that under the current temperature. In these conditions, reduced accumulation of snow and a thin humus layer allowed the soil to freeze to deep layers, thereby causing further reduction in soil moisture due to poor transfer of water deeper in the soil.