Complex internal architecture of a debris‐flow deposit revealed using ground‐penetrating radar,Cass, New Zealand

Previous research on debris‐flow deposit structure typically reports little to no visually discernible stratigraphy. The preliminary findings presented here provide evidence for more complex internal deposit architecture with inverse grading and subunits thought to reflect individual flow surges. Ground‐penetrating radar surveys, geospatial data and field observations are used to describe 10 subunits traceable over the 14 lateral radargrams imaging the lower 38 m of the deposit. Additional subunits are depicted further upslope in a longitudinal transect. As well as demonstrating the need for continued investigation of deposit architecture using non‐traditional techniques, these results may help improve future interpretations of post‐event deposits.     

Metal distributions in seawater,sediment and marine benthic macroalgae from the South Australian coastline

Algal species which are ubiquitous along the coastlines of many countries reflect the environmental conditions of the coastal seawater and may serve as useful biomonitors of anthropogenic pollution. Heavy metal concentrations of ten elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of potential environmental concern were determined in seawater, sediments and twelve species of benthic marine macroalgae from four locations (Glenelg, Port Adelaide, Port Broughton and Port Pirie) along the South Australian coastline. The four sites chosen represented varying degrees of metal contamination, where the capacity for benthic macroalgae to accumulate heavy metals from the environment was evaluated. Spatial differences in heavy metal concentration in both seawaters and sediments were observed at all sites with the highest concentrations of heavy metals including Cd (125 μg g^?1), Pb (2,425 μg g^?1) and Zn (7,974 μg g^?1) found in the finer sediment fractions (<250 μm) of Port Pirie. While all algal species studied (Acrosorium polyneurum, Anotrichium tenue, Cystophora Cephalornithos Cystophora monillifera, Cystophora monilliformis, Dictyopteris australis, Gelidium micropterum, Gracilaria, Hormophysa Cuneiformis, Sargassum cinctum, Scaberia agardhii and Ulva lactuca) accumulated metals to varying degrees, Blindigia marginata was a good biomonitor species for a number of metals including Cd, Co, Cr, Fe, Pb and Zn, exhibiting both relatively high total metal concentrations and significant concentration factors.     

Closing the Gap Between Researchers and Policymakers: Lessons from the History of Fisheries Management in the United States

Increases in sea surface temperature have led to distributional changes in many commercially exploited fish species. These changes have already led to conflict over mackerel fisheries, arising from demand for fair resource apportionment and desire to manage the fishery sustainably. In order to develop adaptable management strategies for complex ocean fishery systems, policymakers and researchers must move beyond a reactive producer–consumer relationship to develop proactive, supportive collaborations. The history of U.S. national fisheries management is presented as an example of this transition. Building cooperative capacity over the last two centuries has lead to a more systematic understanding of the oceans, and has led to success in reducing the number of overfished stocks. Similar development of cooperation between policymakers and researchers on an international scale may be the surest way to develop management strategies adaptable enough to withstand challenges posed by future climate change.     

The Impact Of Extreme Summer Melt on Net Accumulation of an Avalanche Fed Glacier,as Determined by Ground‐Penetrating Radar

Glacier mass balance is more sensitive to warming than cooling, but feedbacks related to the exposure of previously buried firn and ice in very warm years is not generally considered in sensitivity studies. A ground‐penetrating radar survey in the accumulation area of Rolleston Glacier, New Zealand shows that five years of previous net accumulation was removed by melt from parts of the glacier above the long‐term equilibrium line altitude during a single negative mass balance year. Rolleston Glacier receives a large amount of accumulation from snow avalanches, which may temporarily buffer it from climate warming by providing additional mass that has accumulated at higher elevations, effectively increasing the elevation range of the glacier. However, glaciers reliant on avalanche input may have high sensitivity to climatic variations because the extra mass is concentrated on a small part of the glacier, and small variations in avalanche input could have a large impact on overall glacier accumulation. Further research is needed to better estimate the amount and spatial distribution of accumulation by avalanche in order to quantify the climate sensitivity of small avalanche‐fed glaciers.     

A new test for Alfvén waves in interplanetary space

A method of testing for the existence of Alfvén waves using only magnetic-field data is given. It is shown that cross-spectral analysis of the magnetic-field components can be a useful tool in distinguishing between Alfvén waves and magnetosonic waves in interplanetary space.     

The Soft X-ray Telescope for the SOLAR-A mission

The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce X-ray movies of flares with excellent angular and time resolution as well as full-disk X-ray images for general studies. A selection of thin metal filters provide a measure of temperature discrimination and aid in obtaining the wide dynamic range required for solar observing. The co-aligned SXT aspect telescope will yield optical images for aspect reference, white-light flare and sunspot studies, and, possibly, helioseismology. This paper describes the capabilities and characteristics of the SXT for scientific observing.After the launch the name of SOLAR-A has been changed to YOHKOH.     

An improved calibration method for the drift of the conductivity sensor on autonomous CTD profiling floats by θ–S climatology

An improved method to estimate the time-varying drift of measured conductivity from autonomous CTD profiling floats has been developed. This procedure extends previous methods developed by Wong, Johnson and Owens [2003. Delayed-mode calibration of autonomous CTD profiling float salinity data by θ–S climatology. Journal of Atmospheric and Oceanic Technology, 20, 308–318] and Böhme and Send [2005. Objective analyses of hydrographic data for referencing profiling float salinities in highly variable environments. Deep-Sea Research Part II, 52, 651–664]. It uses climatological salinity interpolated to the float positions and observed θ surfaces and chooses 10 ‘best’ levels that are within well-mixed mode waters or deep homogeneous water masses. A piece-wise linear fit is used to estimate the temporally varying multiplicative adjustment to the float potential conductivities. An objective, statistical method is used to choose the breakpoints in the float time series where there are multiple drift trends. In the previous methods these breakpoints were chosen subjectively by manually splitting the time series into separate segments over which the fits were made. Our statistical procedure reduces the subjectivity by providing an automated way for doing the piece-wise linear fit. Uncertainties in this predicted adjustment are estimated using a Monte-Carlo simulation. Examples of this new procedure as applied to two Argo floats are presented.     

Formation of syngenetic and early diagenetic iron minerals in the late Archean Mt. McRae Shale, Hamersley Basin, Australia: New insights on the patterns, controls and paleoenvironmental implications of authigenic mineral formation

A section through the late Archean Mt. McRae Shale comprising, in ascending order, a lower shale interval (LSI), a banded iron formation (BIF), an upper shale (USI) and a carbonate (C1) has been analyzed for total Fe and Al contents and authigenic Fe present as carbonate, oxide, sulfide and silicate phases. The authigenic mineralogy is controlled by the episodic addition of Fe from hydrothermal activity and removal of Fe by sulfide, relative to rates of clastic sedimentation. The LSI and BIF have mean Fe_T/Al values of 2 and 5, respectively, that record iron enrichment from hydrothermal sources. Iron was precipitated primarily as siderite accompanied by Fe-rich chlorite from anoxic bottom waters rich in dissolved Fe. Pyrite formation was probably limited by the availability of sulfate, which was present at low concentrations and became rapidly depleted. The USI has generally lower Fe_T/Al values (0.6-1.3), similar to those found in Paleozoic shales, with the exception of one interval where enrichment may reflect either a weak hydrothermal source or the operation of an iron shuttle. This interval contains authigenic Fe predominantly as pyrite, where high values for DOP (>0.8) indicate the existence of a water column that became rich in dissolved sulfide (euxinic) when sulfate concentrations increased due to a transient or secular increase in ocean/atmosphere oxygenation. High concentrations of dissolved sulfide maintained low concentrations of dissolved Fe, which allowed only minor amounts of Fe to be precipitated as carbonates and silicates. The USI also has elevated concentrations of organic matter that most probably reflect increased productivity and likely limited euxinia to midportions of the water column on the basin margin. The carbonate C1 represents a basinal chemistry where sulfide has been removed and Fe_T/Al values are ∼1 indicating that hydrothermal activity again produced dissolved Fe-rich bottom waters. Detailed iron speciation of the Mt. McRae Shale can be used to recognize spatial and temporal variations in iron and sulfur inputs to the late Archean Hamersley Basin, just prior to the Paleoproterozoic rise in atmospheric oxygenation, and our refined methods have relevance to all Fe-rich deposits.