Identical digeneans in coral reef fishes from French Polynesia and the Great Barrier Reef (Australia) demonstrated by morphology and molecules

Three coral reef fish species, Zanclus cornutus, Chaetodon vagabundus and Naso lituratus, were collected in French Polynesia and on the Great Barrier Reef, Queensland. These fish species were each infected by one morphologically similar digenean species in both localities; Schistorchis Zancli Hanson, 1953 was found in Zanclus cornutus. Preptetos laguncula Bray and Cribb, 1996 in Naso lituratus and Neohypocreadium dorsoporum Machida and Uchida, 1987 in Chaetodon vagabundus. In addition, on the Great Barrier Reef P. laguncula was also found in Naso unicornis and N. dorsoporum in Chaetodon ephippium and Chaetodon flavirostris. Morphometric differences between the species from the two sites were only slight. Sequences from the second internal transcribed spacer of the ribosomal DNA of each worm revealed total homology or negligible divergence between samples from hosts caught in French Polynesia and on the Great Barrier Reef. These results show that across more than 6000 km these digeneans are similar in morphology and genotype. Some species of fishes and molluscs a-re considered to have distributions that encompass the entire tropical Indo-West Pacific. These findings suggest that at least some of their parasites have similarly broad distributions. (C) 2001 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.

Temperature variation within and between nests of the green sea turtle, Chelonia mydas (Chelonia : Cheloniidae) on Heron Island, Great Barrier Reef

Four temperature data-loggers were placed in each of five green sea turtle nests on Heron Island in the 1998-99 nesting season. Temperatures in all nests increased as incubation progressed due to general sand heating and increased metabolic heat production of the developing embryos. Even at the top of nests no daily diurnal fluctuation in temperature was evident. The temperature of eggs in the middle of the nest increased above those in the nest periphery during the last third of incubation. However, this metabolic nest heating would have little effect on hatchling sex ratio because it occurred after the sex-determining period. Small differences in temperature between regions of a nest persisted throughout incubation and may be important in ensuring the production of at least some individuals of the opposite sex in nests that have temperatures close to either the all-male or all-female determining temperatures. Location and degree of shading of nests had little effect on mean nest temperature, but deeper nests were generally cooler and therefore were predicted to produce a higher proportion of males than were shallower nests. Nest temperature profile data indicated that the 1998-99 nesting season on Heron Island would have produced a strongly female-biased sex ratio amongst hatchlings.

An evaluation of a suburban railway pedestrian crossing safety programme

This study evaluated a programme of educational and environmental (access prevention) interventions designed to reduce the incidence of illegal and unsafe crossing of the rail corridor at a suburban station in Auckland, New Zealand. Immediately after the programme of interventions, the proportion of those crossing the rail corridor by walking across the tracks directly rather than using the nearby overbridge had decreased substantially. Three months later, the decrease was even greater. However, the educational and environmental interventions were introduced simultaneously so that the effects of each could not be separated, nor could other unmeasured factors be ruled out. Anonymous surveys administered immediately before and 3 months after the interventions indicated that while awareness of the illegality of walking across the tracks had increased slightly, perception of risk had not changed. This suggests that the educational interventions may have had less effect than the access prevention measures. (C) 2001 Elsevier Science Ltd. All rights reserved.

PCDDs in the water/sediment-seagrass-dugong (Dugong dugon) food chain on the Great Barrier Reef (Australia)

Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentrations were measured in sediment and seagrass from five locations in or adjacent to the Great Barrier Reef Marine Park. A full spectrum of Cl(5-8)DDs were present in all samples and, in particular, elevated levels of Cl8DD were found. PCDFs could not be quantified in any samples. The PCDD concentrations ranged over two orders of magnitude between sites, and there was a good correlation between sediment and seagrass levels. There were large quantities of sediment present on the seagrass (20-62% on a dry wt. basis), and it was concluded that this was a primary source of the PCDDs in the seagrass samples. The PCDD levels in the seagrass samples were compared with the levels in the tissue of three dugongs stranded in the same region. The relative accumulation of the 2,3,7,8-substituted PCDD congeners in the dugongs decreased by over two orders of magnitude with increasing degree of chlorination. This was attributed to the reduced absorption of the higher chlorinated congeners in the digestive tract, a behaviour that has been observed in other mammals such as domestic cows. (C) 2001 Elsevier Science Ltd. All rights reserved.

Teledermatology: a review

Teledermatology holds great potential for revolutionizing the delivery of dermatology services, providing equitable service to remote areas and allowing primary care physicians to refer patients to dermatology centres of excellence at a distance. However, before its routine application asa service tool, its reliability, accuracy and cost-effectiveness need to be verified by rigorous evaluation. Teledermatology can be applied in one of two ways: it may be conducted in real-time, utilizing videoconferencing equipment, or by store-and-forward methods, when transmitted digital images or photographs are submitted with a clinical history. While there is a considerable range of reported accuracy and reliability, evidence suggests that teledermatology will become increasingly utilized and incorporated into more conventional dermatology service delivery systems. Studies to date have generally found that real-time dermatology is likely to allow greater clinical information to be obtained from the patient. This may result in fewer patients requiring conventional consultations, but it is generally more time-consuming and costly to the health service provider It is often favoured by the patient because of the instantaneous nature of the diagnosis and management regimen for the condition, and it has educational value to the primary care physician. Store-and-forward systems of teledermatology often give high levels of diagnostic accuracy, and are cheaper and more convenient for the health care provider, but lack the immediacy of patient contact with the dermatologist, and involve a delay in obtaining the diagnosis and advice on management. It is increasingly likely that teledermatology will prove to be a significant tool in the provision of dermatology services in the future. These services will probably be provided by store-and-forward digital image systems, with real-time videoconferencing being used for case conferences and education. However, much more research is needed into the outcomes and Limitations of such a service and its effect on waiting lists, as well as possible cost benefits for patients, primary health care professionals and dermatology departments.

Panmixia in Pocillopora verrucosa from South Africa

The genetic structure of six local collections of Pocillopora verrrucosa from six coral reefs in KwaZulu-Natal, South Africa, was examined using allozyme electrophoresis. The six separate reefs lie within two different reef complexes. Twenty-two enzymes were screened on five buffer systems, but only five polymorphic loci (Gpi-1, Gdh-1, Lgg-2, Lpp-1, Est-1) could be consistently resolved. No significant differences in allelic frequencies were detected among the six sites. All local collections were genotypically diverse, with evidence of only very limited clonal replication at each site. Indeed, the ratio of observed to expected genotypic diversity (mean Go:Ge=0.64 +/-0.05 SD), the ratio of observed number of genotypes to the number of individuals (mean Ng:N = 0.65 +/-0.04 SE), and deviations from the Hardy-Weinberg equilibrium indicate that sexual reproduction plays a major role in the maintenance of the populations. No genetic differentiation was found either within (FSR = 0.026 +/-0.003 SE) or between (FRT = 0.000 +/-0.001 SE) reef complexes. The homogeneity of the gene frequencies across the six reefs strongly supports the assumption that the KwaZulu-Natal reef complexes are highly connected by gene flow (Nem=44). The reefs in the southern and central reef complexes along the northern Maputaland coastline can therefore be considered part of a single population.

Stability of nest range, home range and movement of the northern bettong (Bettongia tropica) following moderate-intensity fire in a tropical woodland, north-eastern Queensland

Nest use, home-range characteristics and nightly movements by the northern bettong (Bettongia tropica) were examined before and after a low- to moderate-intensity fire in sclerophyll woodland in north-eastern Australia using radio-telemetry. In all, 23 animals were radio-tracked at three-month intervals between February 1995 and May 1996. During November 1995 a low- intensity experimental fire burned the entire home range of most animals. The northern bettong appeared fairly catholic in choice of nest site, with a variety of nest locations and nesting materials used. Prior to the fire, nests were generally located in areas of dense cover, such as the skirts of grass trees (46%) or grass close to a log (29%). After fire removed most ground cover in the nesting areas of most animals, bettongs used remaining shelter such as boulder piles (45%), recently fallen trees (8%) and patches of unburnt vegetation (21%). Nest areas (10.1 ha) of males were significantly larger than those of females (5.4 ha). Home ranges of both sexes were large (59 ha) and most ranges lacked distinct core areas, suggesting that bettongs used all parts of their home ranges equally. High mean rates of nightly movement by the northern bettong indicated that large distances were moved within home ranges during nightly foraging. No significant fire-related changes were detected in home-range size, home-range location, nest-area location or mean rates of nightly movement, suggesting that the northern bettong is well adapted to the low- and medium-intensity fires that characterise its habitat.

A spongin-boring alpha-proteobacterium is the etiological agent of disease in the Great Barrier Reef sponge Rhopaloeides odorabile

High levels of mortality in the Mediterranean bath sponge industry have raised concerns for the future of sponge farms. Healthy sponges feed predominantly on bacteria, and many harbour a wide diversity of inter- and extra-cellular symbiotic bacteria. Here we describe the first isolation and description of a pathogenic bacterium from an infected marine sponge. Microbiological examination of tissue necrosis in the Great Barrier Reef sponge Rhopaloeides odorabile resulted in isolation of the bacterial strain NW4327. Sponges infected with strain NW4327 exhibited high levels of external tissue necrosis, and the strain was re-isolated from infected sponges. A single morphotype, which had burrowed through the collagenous spongin fibres causing severe necrosis, was observed microscopically. Strain NW4327 was capable of degrading commercial preparations of azo-collagen, providing further evidence of its involvement in spongin fibre necrosis, Strain NW4327 disrupted the microbial community associated with R. odorabile and was able to infect and kill healthy sponge tissue. 16S rRNA sequence analysis revealed that strain NW4327 is a novel member of the alpha-proteobacteria.

Determination of the hemispheric character (i.e. southern or northern latitudinal position) of equatorial ionosonde stations as deduced from long-term recordings of the minimum height of the F-region (h ' F)

The virtual (or minimum) height of the F-region (h'F), recorded over a number of solar cycles for I I equatorial and mid-latitude ionosonde stations, was used to deduce the hemispheric (i.e. southern or northern hemisphere) character of equatorial stations. The semi-annual median monthly height (h'F) variations consist of two components: major local summer maximum and winter sub-maximum (about 5 percent of the summer maximum). This hemispheric pattern was most consistently observed for equatorial stations (within 5degrees of the geomagnetic equator) in a period centred on the local midnight (21-03 LT) but was also present, to a lesser extent, at mid-latitude stations and at other time intervals. It is evident that the physical parameter h'F defines the hemispheric character of an equatorial station which has different (sometimes opposite) geographic and geomagnetic latitudes. There is a sharp transition in the latitudinal character of the stations on both sides of the equator leading to hypothesis that the equal maxima in h'F in December and June solstices are observed at a near-equator position labelled as ionosonde deduced equator (IDE). Such a signature was observed for an American equatorial (both geographic and geomagnetic) station Talara (Peru) which is an experimental support of the hypothesis. The IDE can be another useful parameter characterising the equatorial ionosphere. This finding reveals a new application of the standard ionosonde data in defining the geophysical character of equatorial stations, being an important contribution to space climatology. (C) 2002 Elsevier Science Ltd. All rights reserved.

Drosophilidae (Diptera) of Australia's Northern Territory: Ecology and biogeography

The drosophilid fauna is well documented in eastern Australia but is poorly known in other parts of the continent. This paper summarises what is known of this fauna in the Northern Territory (NT), and includes results from banana trapping in the humid and arid zones. The 42 recorded species include species that breed in fruit, fungi and/or flowers, and a larval predator of scale insects. Drosophilids occur in all three major climate zones (humid, semiarid and arid) but predominate in the humid zone. Banana-attracted species in the humid zone (wet-dry tropics) were common in all sampled habitats: urban, rainforest and open woodland. They included predominantly urban and/or rainforest species. Of the species collected in open woodland, some are likely to be breeding there, whereas others may have been intercepted during movement across the area. The semiarid fauna is a depauperate version of that found in the humid region. Only three species have been recorded in the arid region: an endemic arid specialist, and two cosmopolitan species (D. simulans and D. melanogaster ) in urban Alice Springs. Overall, the NT drosophilid fauna represents a depauperate version of that found in eastern Australia, probably because of climatic factors and natural barriers to range expansion. There is little evidence of regional endemism, with probably only one (and at most three) species endemic to the NT, and no evidence of independent, natural dispersion from nearby Indonesia.

Sediment yield and impacts from river catchments to the Great Barrier Reef lagoon

Land use intensification is estimated to result in an overall increase in sediment delivery to the Great Barrier Reef lagoon by a factor of approximately four. Modelling suggests that, following land use intensification, croplands cause the greatest increase of sediment yield and sediment concentration, whereas erosion of grazing land is the main contemporary source of sediments, primarily owing to the large spatial extent of this land use. The spatial pattern of sediment yield to the coast after land use intensification is strongly correlated with the pattern under natural conditions, although the greatest increase is estimated to have occurred in the wet-dry catchments. Sediment transport and resuspension processes have led to the development of a strongly sediment-partitioned shelf, with modern mud-rich sediments almost exclusively restricted to the inner and inner-middle shelf, northward-facing embayments and in the lee of headlands. Elevated sediment concentrations increase the potential transport rates of nutrients and other pollutants. Whether increased sediment supply to the coastal zone has impacted on reefs remains a point of contention. More sediment load data need to be collected and analysed in order to make detailed estimates of catchment yields and establish the possible sediment impact on the Great Barrier Reef.