Arsenic in marine fish and invertebrates

An environmental survey has been undertaken on the Pacific coast of Canada to document natural background levels of a number of heavy metals, including arsenic, in various species of marine fish and invertebrates. The majority of fish studied from four different sampling locations near a proposed mine site, contained arsenic with levels ranging from less than 0.4 to 37.8 mg/kg (wet weight). Crabs were found to contain the highest level of arsenic of all marine organisms tested. Results indicate that arsenic accumulates in marine fish and invertebrates and may possibly be a micronutrient.     

Relations between surface deformation,fault geometry,seismicity, and rupture characteristics during the El Asnam (Algeria) earthquake of 10 October 1980

The El Asnam earthquake of October 10, 1980 (M_s=7.3) produced surface faulting on a northeast-trending thrust fault of 30 km length with displacements of up to 6.5 m, though average displacements were about 3 m. In addition, widespread tensional features were formed, some in clear association with folding above the thrust, and others, in an area beyond the exposure of the thrust at the surface, which may be related to buried reverse faults.The observed thrust fault is split into southern, central and northern segments. Local and teleseismic data are examined to show that the main shock nucleated at the southwest end of the fault, and propagated 12 km northeast where a second rupture of approximately equal moment occurred, continuing the faulting a further 12 km northeast along the central segment. Both ruptures nucleated at about 8–10 km depth. Displacements were largest on the central segment, where they were probably enlarged by aftershocks, including one of m_b=6.1 three hours after the main shock. The northern segment was much shorter than the other two, and showed smaller displacement.The junctions between fault segments are marked by distinct geomorphological characteristics and a change in strike of the faulting, as well as a sudden drop in the observed displacement. It appears that the rupture development is influenced by the changes in fault geometry between segments, and that such junctions or barriers have persisted through much of the late Quaternary.     

A Snapshot of the Sun Near Solar Minimum: The Whole Heliosphere Interval

We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum.     

Rift kinematics preserved in deep-time erosional landscape below the northern North Sea

Our understanding of continental rifting is, in large parts, derived from the stratigraphic record. This record is, however, incomplete as it does not often capture the geomorphic and erosional signal of rifting. New 3D seismic reflection data reveal a Late Permian-Early Triassic landscape incised into the pre-rift basement of the northern North Sea. This landscape, which covers at least 542 km², preserves a drainage system bound by two major tectonic faults. A quantitative geomorphic analysis of the drainage system reveals 68 catchments, with channel steepness and knickpoint analysis of catchment-hosted palaeo-rivers showing that the landscape preserved a >2 Myr long period of transient tectonics. We interpret that this landscape records a punctuated uplift of the footwall of a major rift-related normal fault (Vette Fault) at the onset of rifting. The landscape was preserved by a combination of relatively rapid subsidence in the hangingwall of a younger fault (Øygarden Fault) and burial by post-incision sediments. As such, we show how and why erosional landscapes are preserved in the stratigraphic record, and how they can help us understand the tectono-stratigraphic evolution of ancient continental rifts.     

The complex gravitational lens system B1933+503

We report the discovery of the most complex arcsec-scale radio gravitational lens system yet known. B1933+503 was found during the course of the CLASS survey and MERLIN and VLA radio maps reveal up to 10 components. Four of these are compact and have flat spectra; the rest are more extended and have steep spectra. The background lensed object appears to consist of a flat-spectrum core (quadruply imaged) and two compact 'lobes' symmetrically disposed relative to the core. One of the lobes is quadruply imaged while the other is doubly imaged. An HST observation of the system with the WFPC2 shows a galaxy with an axial ratio of 0.5, but none of the images of the background object is detected. A redshift of 0.755 has been measured for the lens galaxy.     

Characterisation of brown coal humic acids and modified humic acids using pyrolysis gcms and other techniques

It has been proposed that Victorian brown coal can be considered as a two-component structure — a lignocellulosic “host”, containing various amounts of weakly bound or entrapped “guest” material together with very small amounts of inorganic and/or mineral matter. The latter predominantly consists of wax esters and/or terpenoid material. In this paper we describe attempts to gain structural information regarding the more complex, “host” component of the coal. Our initial model compound has been humic acid that can be readily obtained from the coal by alkaline extraction. It has been found that “pure” humic acid, free from material associated with the “guest” components of the coal, can be obtained by a highly selective, low-yielding alkaline extraction. This humic acid has been studied by nmr spectroscopy and pyrolysis gas chromatography-mass spectroscopy (py-gc/ms). The products arising from py-gc/ms have been compared with those obtained from similar pyrolysis of whole coals. Alkylation of humic acids using alkyl halides in the presence of base has been successfully carried out and reactivity of the resulting materials compared with those of the parent coal and humic acid.     

Marine renewable energy: The ecological implications of altering the hydrodynamics of the marine environment

Many countries now recognise the need for mitigation of climate change induced by human activities and have incorporated renewable energy resources within their energy policy. There are extensive resources of renewable energy within the marine environment and increasing interest in extracting energy from locations with either large tidal range, rapid flow with and without wave interaction, or large wave resources. However, the ecological implications of altering the hydrodynamics of the marine environment are poorly understood. Ecological data for areas targeted for marine renewable developments are often limited, not least because of the considerable challenges to sampling in high energy environments. In order to predict the scale and nature of ecological implications there is a need for greater understanding of the distribution and extent of the renewable energy resource and in turn, of how marine renewable energy installations (MREIs) may alter energy in the environment. Regional ecological implications of a MREI need to be considered against the greater and global ecological threat of climate change. Finally, it is recommended that the identification of species and biotopes susceptible to the removal of hydrokinetic energy could be a suitable strategy for understanding how a MREI may alter flow conditions.     

A CME mass distribution derived from SOLWIND coronagraph observations

Using estimates of the masses of nearly 1000 CMEs observed by SOLWIND from Howardet al. (1985), we re-plot the numbers of CMEs as a function of CME mass on a log-linear plot. The plot is significant in that it shows a linear trend over more than a decade of CME masses. The plot indicates a simple form for the distribution of the CME masses and allows an easy determination of the total mass ejected into the solar wind in the form of CMEs. We find that approximately 16% of the solar wind at solar maximum can be comprised of CME mass. There is no indication that the numbers of low-mass CMEs increase in number above the trend set by the more massive ones. Specifically, there is no increase in the numbers of small CMEs such that the whole of the solar wind can be comprised of them.