Holocene cool‐water carbonate and terrigenous sediments from southern Spencer Gulf,South Australia

Holocene sediments from southern Spencer Gulf are cool‐water carbonate‐rich gravels and sands, dominated by molluscs and Bryozoa. Five sedimentary fades are recognized: (i) molluscan gravel; (ii) branching coralline‐algal gravel, associated with shallow partially protected environments; (iii) molluscan‐biyozoan sand; (iv) mixed bioclastic sand, representative of the deeper central region of the lower gulf; and (v) bryozoan gravel, an isolated fades developed in a semi‐protected micro‐environment. The southern gulf is characterized by complex oceanographic conditions together with variations in water depth and substrate. The sediments share the characteristics of both the southern shelf and upper Spencer Gulf. Grain‐size distribution and sedimentary facies are controlled by a combination of all the above processes. Past sea level fluctuations are recognized from sea floor strand‐line deposits. The relic component of the palimpsest sediments has eroded from the Pleistocene aeolianite dunes. The sediments, therefore, reflect both the modern marine and past environments.     

Sabkha and playa environments in late Proterozoic grabens,Willouran Ranges,South Australia

We have reconstructed the depositional environment of sulphate‐dolomite‐sand‐mud sequences of the Callanna Beds of the late Proterozoic Adelaidean System in three areas of the Willouran Ranges, South Australia. We interpret the Callanna Beds which represent the earliest Adelaidean sediments as having been deposited in a series of discrete shallow cratonic basins. The sequences in all three areas consist of cyclic hypersaline sand‐shale‐carbonate sheets and wedges. Hypersalinity has been inferred from a study of evaporites and their pseudomorphs, which imply basin evolution in sabkha and playa palaeoenvironments. We interpret the Callanna Beds in the Willouran Ranges to have been formed in playa lake or prograding sabkha complexes, that formed in a series of yoked half‐grabens within the tectonic setting of the Adelaide palaeorift.     

Tangled lines in New Zealand's quota management system: The process of including recreational fisheries

This article uses New Zealand as a case study of processes relating to the inclusion of recreational fisheries in modern fisheries management systems based on Individual Transferable Quotas (ITQs). The New Zealand case highlights challenges governments often meet when attempting to integrate the recreational sector into fisheries management, including: (a) resistance to restrictions on what has historically been free-of-charge public access to fish for recreational purposes and (b) the fragmented character of the recreational sector, which makes it difficult to have recreational interests attend to their management role and responsibilities.     

Phosphatic concretions and nodules from the upper continental slope,northern New South Wales

Phosphatic concretions and nodules, some of which are coated with goethite, have been dredged at depths between 210 and 385 m from the upper continental slope off northern New South Wales. Some of these appear to have been concentrated on a low sea level terrace at a depth of about 210 m by wave action, while deeper‐water non‐abraded examples may have been winnowed from host sediments by relatively gentle current activity. Similarities in structure, mineralogy and age of contained fauna are noted between nodules described in this paper and phosphatic nodules from the California Continental Borderland, the Chatham Rise off New Zealand and Cainozoic sediments outcropping in Victoria. It is proposed that the Eastern Australian material formed as phosphatic concretions within phosphorus‐enriched slope sediments during diagenesis and that they have since been winnowed, exposed and in some cases re‐cemented into agglomerations on the sea floor in areas of low sedimentation rate.     

Dissolved organic matter (DOM) export to a temperate estuary: seasonal variations and implications of land use

Inputs of dissolved carbon, nitrogen, and phosphorus were assessed for an estuary and its catchment (Horsens, Denmark). Seasonal patterns in the concentrations of DOM in the freshwater supply to the estuary differed depending on the soil and drainage characteristics of the area. In streams draining more natural areas the, patterns observed were largely driven by seasonal temperature fluctuations. The material exported from agricultural areas was more variable and largely controlled by precipitation events. Positive exponential relationships were found between the nitrogen and phosphorus loading, and the percentage of catchment area used for agriculture. Colored DOM (CDOM) loading measurements were found to be a good predictor of dissolved organic carbon (DOC) loading across the different subcatchments, offering a rapid and inexpensive alternative of operationally monitoring DOC export. For all the dissolved nutrient inputs to the estuary, dissolved inorganic nitrogen (DIN) and dissolved organic phosphorus dominated the loadings. Although 81% of the nitrogen annually supplied to the estuary was DIN, 83% of the nitrogen exported from the estuary was dissolved organic nitrogen (DON). Results show that increasing the area of the catchment covered by forest and natural pastures would have a positive effect on the trophic status of the estuary, leading to a considerable decrease in the phosphorus loading and a shift in the nitrogen loading from DIN to DON. Such a change in land use would also increase the export of DOC and CDOM to the estuary having the potential to increase oxygen consumption and reduce the photic depth.     

Towards a new galaxy template library for multi-colour classification

The COMBO-17 survey cite(Wolf et al., 2002) contains ≈ 40000 galaxies down to R=24 mag on an area of one square degree, obtained with the wide field imager at the 2.2 m telescope at La Silla. A multi-colour classification on the basis of 5 broadband and 12 medium band filters (=17 bands) yields accurate redshifts (σ _z ≤ 0.01 at the bright end up to σ _z ≈ 0.1 at the faint end) and spectral energy distribution types (SEDs) when using observed galaxy templates from (Kinney et al.,1996). However, there is an obvious weakness in this classification scheme: The relation between star formation history and SED remains unclear. It is therefore impossible to draw firm conclusions about the age of the underlying stellar population and the expected aging between z ≈ 1 and z ≈ 0 can not be quantified. We will present first results of our attempt to replace the observed templates with model spectra from the PEGASE code (Fioc and Rocca-Volmerange, 1997), in order to get a better handle on the star formation history. This revised version was published online in August 2006 with corrections to the Cover Date.     

Evolution of late proterozoic to early paleozoic Adelaide foldbelt, Australia: Comparisons with postpermian rifts and passive margins

A tectonic and sedimentary facies model is proposed to explain progressive evolution of the late Proterozoic to early Paleozoic Adelaide Rift (Geosyncline) of southern Australia. Tectonic and stratigraphic similarities are noted between the Adelaide Rift and many post Permian rifts and passive continental margins. Also the time span of the pre oceaniccrust accretion stage of the rifting process may be of the same order of magnitude, both in the Adelaide Rift and in post-Permian passive margins. These observations suggest that the underlying cause of the rifting process and the resultant crustal response have not changed significantly since late Precambrian times. More specifically the so-called “breakup unconformity”, observed in stratigraphic sequences beneath many present day passive continental margins, has been shown by various authors to correlate in time with earliest oceanic crust accretion, and it often separates underlying non-marine or paralic from fully marine shelf strata. In the Adelaide Rift, the unconformable Precambrian—Cambrian boundary is proposed as the analogue of this breakup unconformity, thereby explaining the apparently sudden influx of largely marine metazoans in Cambrian strata immediately above this unconformity.     

Distribution of detrital minerals in recent carbonate sediments from the Shaul Shelf,Northern Australia

Detrital minerals in Recent sediments from the Sahul Shelf show a well‐defined distribution pattern which can be related to nearby river estuaries. Two major contrasting heavy mineral provinces are evident, characterized in turn by an unstable and a stable suite of minerals. A zone of relatively high feldspar content coincides with the unstable heavy mineral province. The source of the detrital grains is considered to be the dissected lateritic hinterland, and the depth of dissection in any area may determine whether stable or unstable minerals are supplied to the ocean.     

Fluxes of dissolved combined neutral sugars (polysaccharides) in the Delaware estuary

This project examined concentrations, composition and turnover neutral sugars in the Delaware estuary to gain insights into dissolved inorganic nitrogen (DIN) use by heterotrophic bacteria and into the lability and diagenetic state of dissolved organic material (DOM) during passage through the estuary. Dissolved free monosaccharides were not measurable (<5 nM) in the estuary whereas concentrations of dissolved combined neutral sugars (DCNS) were high, much higher than observed in oceanic waters. DCNS made up a similar fraction of dissolved organic carbon (DOC) as in the oceanic waters examined to date, and the monosaccharide composition of the DCNS pool was similar to that of oceanic waters. The composition did not vary substantially within the estuary or seasonally, but it did vary among three size fractions of the organic matter pool. Glucose was enriched in the low molecular weight fraction of DOC and in particulate material, whereas the high molecular weight DOC fraction was slightly depleted in glucose. Depletion experiments indicated that DCNS is not used extensively on the day time scale in the Delaware estuary, although freshly-produced polysaccharides may still be important carbon sources for heterotrophic bacteria. The very low concentrations of free monosaccharides in the Delaware estuary help to explain why DIN use by heterotrophic bacteria is relatively low in this estuary. Although DOC-DIN interactions in the Delaware apparently differ from oceanic waters, the portion of DOM traced by DCNS, which is thought to be the labile fraction, appears to be similar to that of oceanic DOM, suggesting that organic material in the estuary is degraded extensively before being exported to the coastal ocean.