Changes in seabed morphology, mud temperature and free gas venting at the Håkon Mosby mud volcano, offshore northern Norway, over the time period 2003–2006

The Håkon Mosby mud volcano is a 1.5-km-diameter geological structure located on the Southwest Barents Sea slope at a water depth of 1,270 m. High-definition seabed mapping of the mud volcano has been carried out in 2003 and 2006. A comparative analysis of the bathymetry and backscatter maps produced from the two surveys shows subtle morphological changes over the entire crater of the mud volcano, interpreted to be the consequence of mud eruption events. Mud temperature measurements point to a persistently warm mud at shallow depth in the crater. This is explained by upward fluid advection, rather than conductive cooling of mud flows. The small-scale spatial variability in the temperature distribution may be related to mud outflows or changes in the fluid flow regime. Furthermore, the locations of free gas venting observed in 2006 were found to differ from those of 2003. Our observations of overall similar topographic profiles across the mud volcano in 2003 and 2006 suggest that eruption events would have been modest. Nevertheless, the data bring evidence of significant change in activity even over short time intervals of only 3 years. This may be a characteristic shared by other submarine mud volcanoes, notably those considered to be in a quiescent stage.     

Polycyclic aromatic hydrocarbons in water,mussels (Brachidontes sp., Tagelus sp.) and fish (Odontesthes sp.) from Bahía Blanca Estuary,Argentina

Polycyclic aromatic hydrocarbons (PAHs), one of the major groups of anthropogenic environmental pollutants, were firstly identified and measured in coastal waters, native mussels and fish of an industrialized South American estuary.     

Behavior of Major and Trace Elements during Ore Deposition: Example from the Low-Sulfidation Pantingan Gold System, Mount Mariveles, Bataan, Philippines

The evaluation of the relatively fresh host rock and altered rock samples associated with the Pantingan Gold System exposed in Mount Mariveles, Bataan yield several notable observations that are useful in pinpointing potential gold pathfinder elements. Geochemical and petrologic analysis showed that the altered rocks can be subdivided into rocks that underwent propylitic alteration (group 1), argillized rocks with silica contents similar to those of the fresh host rocks (group 2), argillized but not strongly silicified rocks (group 3) and argillized and strongly silicified rocks (group 4). Selected element ratio patterns in the altered rocks and gold concentrations in gold‐bearing quartz veins vary between the rock groups. Moreover, mass balance calculation also reflected the geochemical observations pertaining to the gains and losses of SiO_2, Fe₂O₃+ MgO, CaO + Na₂O and K₂O, which are believed to be chemical reactions (i.e. breakdown of plagioclase, silica inundation or leaching, sulfide and calcite formation) caused by the influx of hydrothermal fluids.     

In situ measurements of soil saturated hydraulic conductivity: Assessment of reliability through rainfall–runoff experiments

The saturated hydraulic conductivity, K_s, is a soil property that has a key role in the partitioning of rainfall into surface runoff and infiltration. The commonly used instruments and methods for in situ measurements of K_s have frequently provided conflicting results. Comparison of K_s estimates obtained by three classical devices—namely, the double ring infiltrometer (DRI), the Guelph version of the constant‐head well permeameter (GUELPH‐CHP) and the CSIRO version of the tension permeameter (CSIRO‐TP) is presented. A distinguishing feature in this study is the use of steady deep flow rates, obtained from controlled rainfall–runoff experiments, as benchmark values of K_s at local and field‐plot scales, thereby enabling an assessment of these methods in reliably reproducing repeatable values and in their capability of determining plot‐scale variation of K_s. We find that the DRI grossly overestimates K_s, the GUELPH‐CHP gives conflicting estimates of K_s with substantial overestimation in laboratory experiments and underestimation at the plot scale, whereas the CSIRO‐TP yields average K_s values with significant errors of 24% in the plot scale experiment and 66% in laboratory experiments. Although the DRI would likely yield a better estimate of the nature of variability than the GUELPH‐CHP and CSIRO‐TP, a separate calibration may be warranted to correct for the overestimation of K_s values. The reasons for such discrepancies within and between the measurement methods are not yet fully understood and serve as motivation for future work to better characterize the uncertainty associated with individual measurements of K_s using these methods and the characterization of field scale variability from multiple local measurements.     

Middle Eocene low-paleolatitude radiolarian evidence for the Cabog Formation,Central East Luzon,Philippine Mobile Belt

The Cabog Formation, newly established herein and exposed in central East Luzon, Philippine Mobile Belt, is defined in age by the occurrence of radiolarians. The radiolarian assemblage is correlative with the middle Eocene and suggests a low paleolatitude affinity. The correlation, sedimentary environment, and the tectonic significance are discussed. The Cabog Formation is correlative with the distal part of the middle–late Eocene Caraballo Formation, which is exposed in the northeastern side of the Philippine Fault Zone. The sandstone composition and radiolarian age suggest that the Cabog Formation represents the first depositional stage in the early arc setting. The northward migration of the formation is also estimated in relation with the Philippine Sea Plate motion along the Older Philippine Fault from the equatorial area.     

The Value of Ωo in a Colliding Bubble Universe

We present a calculation of the probability distribution of the invariant separation between the nucleation centers of colliding bubbles resulting from the decay of a false de Sitter space vacuum. We also discuss the probability of a collision with a `third' bubble. This study is motivated by the proposed `colliding bubble braneworld' scenario in which the value of Ω₀ today is a function of this invariant. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Impact of CoRoT on Close Binary Research

The space experiment CoRoT will provide continuous monitoring and high accuracy light curves of about sixty thousand stars. Selected binary systems will be observed in the Additional Program frame as targets of long and continuous pointed observations. Moreover, thousands of new binaries will certainly be detected and hundreds of them will have extremely accurate light curves. This will allow studies of fine effects on the light curves, monitoring of stellar activity and, in combination with ground-based observations, will provide exquisite determination of stellar parameters. Among the new discoveries of interesting systems of special value will be those of low mass binaries.     

Putting stakeholder engagement in its place: how situating public participation in community improves natural resource management outcomes

Stakeholders in natural resource management decisions are also multifaceted individuals and members of communities; as such, they bring complex histories, experiences, values, aspirations, and relationships to public participation processes. When these processes fail to take this social context into account, multiple problems can result, including a perceived lack of process trustworthiness; perceived focus on issues that seem immaterial or irrelevant; failure to equitably represent and take account of diverse voices; and failure to engage participants in productive dialogue. In this article we evaluate the Community Voice Method (CVM) as a way of addressing those problems by better situating public participation in place. CVM is a mixed-method approach to public participation in which stakeholders are interviewed and the interview data is presented through a film, which is then screened at public meetings to catalyze dialogue. We draw on 14 years of CVM projects addressing natural resource management issues in the United States, the United Kingdom, and the Caribbean. Through an overview of nine projects and their results, and more in-depth consideration of three, we elucidate how this method fosters trustworthy, relevant, representative, and productive public participation that has resulted in community capacity-building, institutional capacity-building, and stakeholder-guided policymaking.

     

Ecotones as Indicators of Changing Environmental Conditions: Rapid Migration of Salt Marsh–Upland Boundaries

Ecotones, the narrow transition zones between extensive ecological systems, may serve as sensitive indicators of climate change because they harbor species that are often near the limit of their physical and competitive tolerances. We investigated the ecotone between salt marsh and adjacent upland at Elkhorn Slough, an estuary in California, USA. Over a period of 10 years, we monitored movement of the ecotone–upland boundary, plant community structure, and physical factors likely to drive ecotone response. At three undiked sites, the ecotone boundary migrated about 1 m landward, representing a substantial shift for a transition zone that is only a few meters wide. Analysis of potential correlates of this upward migration suggests that it was driven by increased tidal inundation. Mean sea level did not increase during our study, but inundation at high elevations did. While the ecotone boundary responded dynamically to interannual changes in inundation at these undiked sites, the plant community structure of the ecotone remained stable. At two diked sites, we observed contrasting patterns. At one site, the ecotone boundary migrated seaward, while at the other, it showed no consistent trend. Diking appears to eliminate natural sensitivity of the ecotone boundary to interannual variation in oceanic and atmospheric drivers, with local factors (management of water control structures) outweighing regional ones. Our study shows that the marsh–upland ecotone migrated rapidly in response to environmental change while maintaining stable plant community structure. Such resilience, stability, and rapid response time suggest that the marsh–upland ecotone can serve as a sensitive indicator of climate change.     

Definition of areas of probable risk to human health posed by As and Pb in soils and ground-level dusts of the surrounding area of an abandoned As-sulfide mine in the north of Portugal: part 1

The aim of this study is to assess the potential health risk posed by As and Pb in the soils of the Pintor mine area. The site was never remediated but a residential area is being constructed in the mine land, next to the smelters, a fact that raised some concern about the probable risk posed by potentially harmful elements in the soil to the health of the residents. 132 samples were collected and analyzed by ICP-MS to determine total metal concentrations. The soluble fraction of As in the soil was obtained using 1 M NH₄ Acetate, pH 4.5. To assess the probable risk, total concentrations are compared with the soil guideline value established for the UK. Exposure through soil ingestion is probable in and around the residential area that has higher As and Pb concentrations, and therefore is classified as area with a potential health risk.