A fine balance: Accommodation dominated control of contemporaneous cool-carbonate shelf-edge clinoforms and tropical reef-margin trajectories,North Carnarvon Basin,Northwestern Australia

The concurrent development of a cool-carbonate Miocene clinoform system and the tropical reef which developed on its shelf in the North Carnarvon Basin is studied. The study, based on seismic interpretation and geometrical analysis, seeks to investigate how the architecture of the clinoforms develops in relation to the advance of the reef-margin, providing a proxy for discussing contemporaneous shoreline versus shelf-edge development. The progradation of the reef and shelf-edge often display a closely mirrored development, although the reef twice advances an order of two to three times the concurrent advance of the shelf-edge. The forced regression of the second advance, as compared to the normal regression during the first, is observed in proportionally higher input of sediment towards advance of the shelf-edge and toe, along with a gentler slope. The inability of the shelf-edge to keep pace with the reef-margin (and by proxy the shoreline) during lower accommodation/sedimentation is a result of the increased volume of sediment required to match reef-margin advance beyond the shelf-edge. Increased accommodation/sedimentation ratios promote higher trajectories where the volumes on shelf and slope are more balanced and the development more closely matched. The observed matched development of reef and shelf-edge during both limited and increased slope sedimentation, suggest that accommodation is the dominant control on the location and trajectory of both ‘shoreline’ and shelf-edge, and that excess sediment is deposited along the slope.     

Meteorological study of the first observation of red sprites from Poland

The first red sprite events scientifically observed from Poland on 20/21 July 2007, during the two-week SPARTAN Sprite-Watch 2007 campaign, are analysed in the context of the meteorological conditions over Poland and the Czech Republic at that time. The phenomena were detected and recorded from the IMWM High-Mountain Meteorological Observatory at Mount Śnieżka using a low-light television CCD camera. Meteorological conditions over the south-west Poland were monitored on the basis of information from the Polish and Czech meteorological radar and lightning detection systems and also from satellite infra-red difference images, indicating the development of thunderstorm clouds over central Europe. Four sprite events detected in the night-time of 20/21 July indicate that in this region sprites are produced by massive storm cells built on warm fronts which are supplied by warm and humid tropical air masses during local summer thunderstorm season.     

Microheterogeneity of element distribution and sulfur speciation in an organic surface horizon of a forested Histosol as revealed by synchrotron-based X-ray spectromicroscopy

In recent years, the relevance of physico-chemical heterogeneity patterns in soils at the micron and submicron scale for the regulation of biogeochemical processes has become increasingly evident. For an organic surface soil horizon from a forested Histosol in Germany, microspatial patterns of element distribution (sulfur, phosphorus, aluminium, silicon) and S speciation were investigated by synchrotron-based X-ray spectromicroscopy. Microspatial patterns of S, P, Al and Si contents in the organic topsoil were assessed for a sample region of 50 μm × 30 μm by spatially resolving μ-XRF. Sulfur speciation at four microsites was investigated by focused X-ray absorption near edge structure (μ-XANES) spectroscopy at the S K-edge. The results show a heterogeneous distribution of the investigated elements on the (sub)micron scale, allowing the identification of diatoms, aluminosilicate mineral particles and sulfide minerals in the organic soil matrix. Evaluation of the S K-edge μ-XANES spectra acquired at four different microsites by linear combination fitting revealed a substantial microspatial heterogeneity of S speciation, characterized by the presence of distinct enrichment zones of inorganic sulfide and zones with dominant organic disulfide S within a few micrometers distance, and coexistence of different S species (e.g. reduced inorganic and organic S compounds) at a spatial scale below the resolution of the instrument (60 nm × 60 nm; X-ray penetration depth: 30 μm).     

Restriction of sponges to an atoll lagoon as a result of reduced environmental quality

The lagoon at Palmyra Atoll in the central Pacific was subject to major military modifications during WWII and now the dominant fauna on the lagoon’s hard substrate are sponges, not corals. In this study, we quantified the physical and biological factors explaining the variation in sponge distribution patterns across 11 sites to determine the potential for the sponges in the lagoon at Palmyra to invade the surrounding reef systems. Significant differences in sponge assemblages were found among all but three sites. For all the models we examined the strongest environmental relationships were found for variables related to sedimentation/turbidity and food/habitat availability. Our findings suggest that the sponges in Palmyra’s lagoon are likely to be restricted to this habitat type where they are associated with conditions resulting from the earlier heavy disturbance and are unlikely to spread to the outer reef environments unless there is a dramatic decline in environmental quality.     

Recommendations on methods for the detection and control of biological pollution in marine coastal waters

Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution.     

Effects of chronic exposure to dispersed oil on selected reproductive processes in adult blue mussels (Mytilus edulis) and the consequences for the early life stages of their larvae

Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015-0.25 mg/l) for 7 months covering the whole gamete development cycle. After 1 month exposure to 0.25 mg oil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7 months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25 mg oil/l. Parental exposure to 0.25 mg oil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2 days post-fertilization; reduced growth 7 days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25 mg oil/l. Similar studies are warranted for risk assessment prognosis.     

Hydrochemical Groundwater Evolution in the Bunter Sandstone Sequence of the Odenwald Mountain Range,Germany: A Laboratory and Field Study

Field and laboratory investigations were performed to identify the principal mechanisms of the hydrochemical groundwater evolution among low mineralised groundwater in the Triassic Bunter sandstone aquifer of the Odenwald low mountain range, central Germany. Hydrochemical composition comprises low pH, SO₄-rich shallow groundwaters issued by springs (Ca-Mg-SO₄-type) grading to SO₄-poor deep groundwaters with near-neutral pH (Ca-HCO₃-type). Batch experiments of the original rock were run to determine primary mineral alteration reactions and the origin of dissolved ions. Principal experimental reactions comprise the decomposition of anorthite, K-feldspar, biotite and jarosite as mineral components of the original sandstone rock and the formation of clay minerals of the smectite group (Ca-montmorillonite, beidellite), and iron hydroxides as secondary minerals. Mobilisation of fluid inclusion in quartz grains contributes to Na and Cl concentrations in the leachates. The evolution of deep groundwater circulation proceeds by mineral alteration reactions calculated by the inverse modelling of both primary and secondary minerals to produce low-T mineral phases. The dissolution of K-feldspar converts Ca-montmorillonite to illite (illitisation). The formation of Na-beidellite correlates with decreasing concentration of Na in solution. Mineral reactions further proceed to the formation of kaolinite as stable mineral phase. As indicated by modelled adsorption curves, the decrease of SO₄ concentrations during groundwater evolution relates to the adsorption of SO₄ on iron hydroxides. The leaching of calcite indicated for individual groundwaters relates to the distribution of loess in the appropriate catchment areas.     

228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

Activities of the naturally occurring radium nuclides ²²⁸Ra, ²²⁶Ra, ²²⁴Ra and ²²³Ra were determined in waters of the open German Bight and adjacent nearshore areas in the North Sea, in order to explore the potential use of radium isotopes as natural tracers of land–ocean interaction in an environment characterised by extensive tidal flats, as well as riverine and groundwater influx. Data collected at various tidal phases from the Weser Estuary (²²⁸Ra: 46.3 ± 4.6; ²²⁶Ra: 17.1 ± 1.1; ²²⁴Ra: 26.1 ± 8.2 to 36.5 ± 6.1; ²²³Ra: 1.8 ± 0.1 to 4.0 ± 0.4), tidal flats near Sahlenburg (²²⁸Ra: 39.3 ± 3.8 to 46.0 ± 4.5; ²²⁶Ra: 15.5 ± 1.5 to 16.5 ± 1.7; ²²⁴Ra: 34.3 ± 2.2 to 85.3 ± 6.3; ²²³Ra: 3.6 ± 0.5 to 8.0 ± 1.2), freshwater seeps on tidal flats near Sahlenburg (²²⁸Ra: 42.1 ± 4.1; ²²⁶Ra: 21.3 ± 2.2; ²²⁴Ra: 5.1 ± 0.9; ²²³Ra: 2.6 ± 1.3) and also in permanently inundated parts of the North Sea (²²⁸Ra: 23.0 ± 2.3 to 28.2 ± 2.8; ²²⁶Ra: 8.2 ± 0.8 to 11.8 ± 1.2; ²²⁴Ra: 3.1 ± 1.0 to 10.1 ± 0.9; ²²³Ra: 0.1 ± 0.02 to 0.9 ± 0.05; units: disintegrations per minute per 100 kg water sample) reveal that, except for the fresh groundwater, the potential end-members of nearshore water mass mixing have quite similar radium signatures, excluding a simple discrimination between the sources. However, the decreasing activities of the short-lived ²²⁴Ra and ²²³Ra isotopes recorded towards the island of Helgoland in the central German Bight show a potential to constrain fluxes of land-derived material to the open North Sea. The largest source for all radium isotopes is generally found on the vast tidal flats and in the Weser Estuary. Future work could meaningfully combine this so-called radium quartet approach with investigations of radon activity. Indeed, preliminary data from a tidal flat site with fresh groundwater seepage reveal a ²²²Rn signal that is clearly lower in seawater.