Performance of grass and eucalyptus riparian buffers in a pasture catchment,Western Australia,part 2: water quality

Declining water quality on the south coast of Western Australia has been linked to current agricultural practices. Riparian buffers were identified as a tool available to farmers and catchment managers to achieve water quality improvements. This study compares 10 m wide regenerating grass and Eucalyptus globulus buffer performance. Surface and subsurface water quality were monitored over a 3‐year period. Nutrient and sediment transport were both dominated by subsurface flow, in particular through the B‐horizon, and this may seriously limit the surface‐runoff‐related functions of the riparian buffers. Riparian buffer trapping efficiencies were variable on an event basis and annual basis. The grass buffer reduced total phosphorus, filterable reactive phosphorus, total nitrogen and suspended sediment loads from surface runoff by 50 to 60%. The E. globulus buffer was not as effective, and total load reductions in surface runoff ranged between 10 and 40%. A key difference between the grass and E. globulus buffers was the seasonality of sediment and nutrient transport. Surface runoff, and therefore sediment and nutrient transport, occurred throughout the year in the E. globulus buffer, but only during the winter in the grass buffer. As a consequence of high summer nutrient and sediment concentrations, half the annual loads moving via surface runoff pathways through the E. globulus buffer were transported during intense summer storms. This study demonstrates that grass and E. globulus riparian buffers receiving runoff from pasture under natural rainfall can reduce sediment and nutrient loads from surface runoff. However, in this environment the B‐horizon subsurface flow is the dominant flowpath for nutrient transport through the riparian buffers, and this subsurface flow pathway carries contaminant loads at least three times greater than surface runoff. Copyright © 2006 John Wiley & Sons, Ltd.     

A VAPID analysis of interstellar lithium in the ζ Oph sightline

We present observations of the Li  i 6708 Å doublet in the ζ Oph sightline, obtained at a resolution of ∼10⁶ and a signal-to-noise ratio of ∼1200, together with supplementary observations of K  i λ 7699 and the Na  i λ 3302 doublet. These observations marginally resolve the main '−15 km s⁻¹' system into its two principal clouds; we model the data using standard physical assumptions, but in a statistically rigorous manner, taking fully into account the hyperfine, doublet and isotopic structure for each species, in each cloud, using a new code, vapid . The average  ⁷Li/⁶Li  ratio determined in this sightline is  1.12±0.20 dex  (68 per cent confidence interval), in excellent agreement with the solar-system (meteoritic) value. The ratios in the individual clouds are determined with less precision, but are also consistent with the solar-system value, as is the total lithium abundance (with little evidence for depletion). The thermal and 'turbulent' broadening in the two clouds is discussed on the basis of observed line widths.     

THE INNISFREE METEORITE FALL: A PHOTOGRAPHIC ANALYSIS OF FRAGMENTATION,DYNAMICS AND LUMINOSITY

The Innisfree meteorite was the third fall for which accurate orbital data were secured from a camera network. Nine fragments were found within three months of the fall with a total mass of 4.58 kg. The ellipse of fall is unusually small because of the steep path in the atmosphere. The photograph from the Vegreville station reveals six trails below 26 km and these are correlated with the six main fragments, all with masses in excess of 300 g. A photometric study indicates that Innisfree had a peak absolute magnitude M_pan = ?12.1 at a height of 36 km. The recovered meteorites provide known masses for the late stages of the photographic trails which, combined with dynamical data, allow luminous efficiencies to be derived with unusual confidence. Late in the flight where shock wave effects dominate ablation, luminous efficiencies vary from 3 × 10^?5 to 5 × 10^?2 for velocities between 3 and 10 km s^?1 and masses from 0.3 to 2.0 kg. The mean luminous efficiency for the entire flight is estimated between 4 × 10^?2 and 8 × 10^?2.     

Non-uniformly rotating,self-gravitating,compressible masses with internal meridian circulation

The structure of self-gravitating, inviscid, compressible fluids is investigated assuming a polytropic relation between pressure and density. A class of solutions with non-uniform rotation and internal meridian circulation are presented and the stream lines of the flow calculated using a perturbation technique.     

Galileiite: A new meteoritic phosphate minera

Abstract— A new mineral named galileiite, NaFe₄(PO₄)₃, has been found within troilite nodules in iron meteorites of the IIIA and IIIB groups. the mineral is optically positive (ω = 1.72, ω = 1.75), colorless in transmitted light and pale amber in reflected light. Grains of galileiite are very small, generally 10 μm or less; rarely, grains are up to 30 μm. It is associated with Ca-free graftonite (or Ca-free sarcopside), chromite and, occasionally, schreibersite. Johnsomervilleite may occur within troilite nodules in the same meteorite as galileiite, but they have never been observed together in the same troilite nodule. Because of the small sample size, single crystal x-ray work was not successful; however, Gandolfi diffraction measurements were made. The three strongest diffraction peaks are 2.71 Å, 3.01 Å and 4.13 Å. On the basis of its composition and similar diffraction pattern, it is considered to be related to johnsomervilleite, fillowite and chladniite, all of which are rhombohedral and isostructural. Galileiite may also be rhombohedral, but that is yet to be demonstrated.     

CMBEAR: Python-Based Recharge Estimator Using the Chloride Mass Balance Method in Australia

The chloride mass balance (CMB) method is widely used to estimate long-term rates of groundwater recharge. In regions where surface water runoff is negligible, recharge can be estimated using measurements of chloride concentrations of groundwater and precipitation, and an estimate of long-term average rainfall. This paper presents the Chloride Mass Balance Estimator of Australian Recharge (CMBEAR), a Jupyter (Python) Notebook that is set up to rapidly apply the CMB method using gridded maps of chloride deposition rates across the Australian continent. For an Australian context, the chloride deposition rate and rainfall maps have been provided. Thus, CMBEAR requires only a spreadsheet with the groundwater chloride concentration, the latitude and longitude of the sample location, and some simple user inputs. CMBEAR may be easily applied in other regions, providing that a gridded chloride deposition map is available. Recharge estimates from CMBEAR are compared against published applications of the CMB method. CMBEAR is also applied to a large dataset from the Northern Territory and is used to produce a gridded map of recharge for western Victoria. CMBEAR provides a reproducible and straightforward approach to apply the CMB method to estimate groundwater recharge.