End-Permian mass extinction pattern in the northern peri-Gondwanan region

The Permian-Triassic extinction pattern in the peri-Gondwanan region is documented biostratigraphically, geochemically and sedimentologically based on three marine sequences deposited in southern Tibet and comparisons with the sections in the Salt Range, Pakistan and Kashmir. Results of biostratigraphical ranges for the marine faunas reveal an end-Permian event comparable in timing with that known at the Meishan section in low palaeolatitude as well as Spitsbergen and East Greenland in northern Boreal settings although biotic patterns earlier in the Permian vary. The previously interpreted delayed extinction (Late Griesbachian) at the Selong Xishan section is not supported by our analysis. The end-Permian event exhibits an abrupt marine faunal shift slightly beneath the Permian-Triassic boundary (PTB) from benthic taxa- to nektic taxa-dominated communities. The climate along the continental margin of Neo-Tethys was cold before the extinction event. However, a rapid climatic warming event as indicated by the southward invasion of abundant warm-water conodonts, warm-water brachiopods, calcareous sponges, and gastropods was associated with the extinction event. Stable isotopic values of δ13Ccarb, δ13Corg and δ18O show a sharp negative drop slightly before and during the extinction interval. Sedimentological and microstratigraphical analysis reveals a Late Permian regression, as marked by a Caliche Bed at the Selong Xishan section and the micaceous siltstone in the topmost part of the Qubuerga Formation at the Qubu and Tulong sections. The regression was immediately followed by a rapid transgression beneath the PTB. The basal Triassic rocks fine upward, and are dominated by dolomitic packstone/wackestone containing pyritic cubes, bioturbation and numerous tiny foraminifers, suggesting that the studied sections were deposited during the initial stage of the transgression and hence may not have been deeply affected by the anoxic event that is widely believed to characterise the zenith of the transgression.

Environmental site assessment for abalone ranching on artificial reef

This study investigated the feasibility of ranching the abalone Haliotis rubra (Leach) and Haliotis laevigata (Donovan) on concrete artificial reefs at a site chosen by industry investors on silty bottom off Altona Beach, Port Phillip Bay, Victoria, Australia. The study started from the premise that artificial reef deployment combined with abalone stock enhancement may achieve the dual purpose of habitat and stock improvement. It evaluated the hydrodynamics of the site in relation to artificial reef structural stability and drift algal transport, the development and ecology of the artificial reef assemblage, and abalone enhancement by seeding the reefs with hatchery juvenile abalone and transplanting adult broodstock abalone. Despite a scarcity of reports on culturing abalone on artificial reef, a literature review examined broadly the functions of artificial reefs, particularly in the context of abalone enhancement, and the relationship between artificial reefs, hydrodynamics and ecology. The major finding was that the success of artificial reef projects is highly dependent on the environment of the chosen site, and that preliminary studies are essential to predict their likely success. This consideration alone provided strong justification to undertake this study. The topography at the Altona site was generally flat, with natural patches of low basalt boulder reef, offering low habitat complexity, yet supporting a diverse range of flora and fauna, including a low-density wild stock of H. rubra. Water depth was a mean of 3.3 m at low tide and 4.4 m at high tide. A single, uncomplicated, concrete artificial reef of H-shape design, was tested as abalone habitat. The hydrodynamic analysis confirmed previous studies of Port Phillip Bay, with mild current speeds of mean 0.045 m.s-1, and maximum-modelled wave height (H1/3) of 1.21 m and period (T1/3) of 4.51 sec. Water temperature ranged from 9.9şC during July to 23.8şC during January, with salinity averaging of 35.5 ppt. The site had a low probability of receiving drift algae, necessary as a food source for abalone, because of its geographic location, potentially affecting ranch productivity. Ecological monitoring of the three-year old artificial reef shows complex changes in the flora and fauna over time, particularly in respect of the sessile fauna. Key differences between the artificial reef and a nearby natural reef community were: lower cover of corallines and late colonisers, such as sponges. High levels of sedimentation were recorded at the Altona site. Hatchery juvenile H. laevigata, with mean survival of 15% after two years and a mean annual growth rate of 39 mm, showed the most promise for outplanting. In comparison, for hatchery juvenile H. rubra, mean survival was 9% after three years and mean annual growth rate was 22 mm. No natural recruitment of H. laevigata was recorded on artificial reef despite transplants of adult broodstock on the reefs. Natural recruitment of H. rubra was also low and insufficient to reliably contribute to abalone ranch stock. Having examined the hydrodynamic, ecological and enhancement attributes of the Altona site, the study concluded that the site was marginally viable for abalone ranching, and that an alternative site near Werribee, 20 km further southwest, had superior attributes for growth and survival of abalone.

Monitoring the marine environment adjacent to a petroleum refinery on Corio Bay, Victoria, Australia /Peter James Gilbert

The objective of the work reported in this thesis was to design and implement an ecological effects environmental monitoring program which would: 1) Collect baseline biological information on sessile epibiotic fouling communities from an area adjacent to a petroleum refinery located on Corio Bay, Victoria, to allow comparison with results of future monitoring for the assessment of long term temporal water quality trends. 2) Detect and — if possible - estimate the magnitude of any influence on epibiotic fouling communities within the Corio Bay marine ecosystem attributable to operations at the Shell Petroleum Refinery. 3) Investigate the extent of thermal stratification and rate of dispersal of the petroleum refinery main cooling-water outfall plume (discharging up to 350,000 tonnes of warmed seawater per day), and its effect on epibiotic communities within the EPA-defined mixing zone. A major component of the work undertaken was the design and development of artificial-substrate biological sampling stations suitable for use under the conditions prevailing in Corio Bay, and the development of appropriate quantitative underwater photographic sampling techniques to fulfil the experimental criteria outlined above. Experimental and other constraints imposed on the design of the stations precluded the simple suspension of frames from jetties or pylons, a technique widely used in previous work of this type. Artificial substrate panels were deployed along three radial transects centred within and extending beyond the petroleum refinery main cooling-water mixing zone. Identical substrate panels were deployed at a number of control sites located throughout Corio Bay, each chosen for differences in their degree of exposure to such factors as water movement, depth, shipping traffic and/or comparable industrial activity. The rate of colonisation (space utilisation) and the development of epibiotic fouling communities on artificial substrate panels was monitored over two twelve-month sampling periods using quantitative underwater photographic sampling techniques. Sampling was conducted at 4-8 week intervals with the rate of panel colonisation and community structure determined via coverage measurements. Various species of marine algae, polychaete tubeworms, hydroids, barnacles, simple and colonial ascidians, sponges, bivalve molluscs and encrusting bryozoans were all detected growing on panels. Communities which established on panels within the cooling-water mixing-zone and those at control sites were compared using statistical procedures including agglomerative hierarchical cluster analysis. A photographic sample archive has been established to allow comparison with similar future studies.

Ingrowth of human mesenchymal stem cells into porous silk particle reinforced silk composite scaffolds : an in vitro study

Silk fibroin protein is biodegradable and biocompatible, exhibiting excellent mechanical properties for various biomedical applications. However, porous three-dimensional (3-D) silk fibroin scaffolds, or silk sponges, usually fall short in matching the initial mechanical requirements for bone tissue engineering. In the present study, silk sponge matrices were reinforced with silk microparticles to generate protein-protein composite scaffolds with desirable mechanical properties for in vitro osteogenic tissue formation. It was found that increasing the silk microparticle loading led to a substantial increase in the scaffold compressive modulus from 0.3 MPa (non-reinforced) to 1.9 MPa for 1:2 (matrix:particle) reinforcement loading by dry mass. Biochemical, gene expression, and histological assays were employed to study the possible effects of increasing composite scaffold stiffness, due to microparticle reinforcement, on in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs). Increasing silk microparticle loading increased the osteogenic capability of hMSCs in the presence of bone morphogenic protein-2 (BMP-2) and other osteogenic factors in static culture for up to 6 weeks. The calcium adsorption increased dramatically with increasing loading, as observed from biochemical assays, histological staining, and microcomputer tomography (μCT) analysis. Specifically, calcium content in the scaffolds increased by 0.57, 0.71, and 1.27 mg (per μg of DNA) from 3 to 6 weeks for matrix to particle dry mass loading ratios of 1:0, 1:1, and 1:2, respectively. In addition, μCT imaging revealed that at 6 weeks, bone volume fraction increased from 0.78% for non-reinforced to 7.1% and 6.7% for 1:1 and 1:2 loading, respectively. Our results support the hypothesis that scaffold stiffness may strongly influence the 3-D in vitro differentiation capabilities of hMSCs, providing a means to improve osteogenic outcomes.

A superamphiphobic coating with an ammonia-triggered transition to superhydrophilic and superoleophobic for oil-water separation

Superhydrophilic and superoleophobic materials are very attractive for efficient and cost-effective oil-water separation, but also very challenging to prepare. Reported herein is a new superamphiphobic coating that turns superhydrophilic and superoleophobic upon ammonia exposure. The coating is prepared from a mixture of silica nanoparticles and heptadecafluorononanoic acid-modified TiO2 sol by a facile dip-coating method. Commonly used materials, including polyester fabric and polyurethane sponge, modified with this coating show unusual capabilities for controllable filtration of an oil-water mixture and selective removal of water from bulk oil. We anticipate that this novel coating may lead to the development of advanced oil-water separation techniques.

High internal phase emulsion (HIPE) xerogels for enhanced oil spill recovery

Oil spills cause serious damage to the aquatic ecosystem and require quick cleanup. Herein we report high internal phase emulsion (HIPE) xerogels for the first time as oil absorbents for enhanced oil spill recovery. The HIPE xerogels absorb diesel from the water-oil mixture in 20-30 seconds. The absorption capacity of the HIPE xerogels ranges from 20 to 32 times for different kinds of oils, and the oils can be recovered simply by being squeezed out, with a recovery rate around 80%. They can be reused at least 40 times without obvious deterioration in oil separation properties from 0 to 45 °C. These novel xerogels are suitable for practical use in oil spill reclamation and wastewater treatment.