Montebello Islands Research Articles

Investigation of the distribution of transuranic radionuclides in marine sediment at the Montebello Islands, Western Australia

Three nuclear weapons tests were conducted in the 1950s at the Montebello Islands, Western Australia. The detonations were of different yields and configurations (two tower tests, one ship test), and led to substantial radionuclide contamination within the surrounding terrestrial and marine ecosystems. The region possesses great ecological and recreational significance, particularly within the marine environment. However, studies conducted so far have largely neglected the marine ecosystem which makes up the majority of the Montebello Island Marine Park and in which most test fallout would have deposited. Here we investigated the distribution of the transuranic radionuclides 238Pu, 239,240Pu and 241Am in marine sediment from the Montebello Islands. Marine sediment samples near Operation Mosaic G2 and Operation Hurricane were collected and analysed by gamma and alpha spectrometry. Activity concentrations of 239,240Pu across both series ranged from 45 to 2900 Bq kg−1, while 241Am levels ranged from 2.8 to 70 Bq kg−1. Higher activity concentrations were observed in sediment near the land-based, higher yield Mosaic G2 test, compared with the ship-based, lower yield Hurricane test. Sediment samples located closer to the detonation site were also observed to have higher activity concentrations. Radioactive particles of 0.94 mm and 1.5 mm in diameter were identified by analysis of size-fractioned sediment via investigation of 152Eu levels, photostimulated autoradiography and point gamma spectroscopy. Particles were confirmed to have transuranic radionuclide interiors, with surface coatings which were dominated by vitrified CaCO3. Their long-term resistance to weathering and subsequent persistence in the marine environment can therefore be attributed to their coated structural form. Our study confirms the persistence of transuranic radionuclides in Montebello Island marine sediment and highlights the need for additional studies to improve our understanding of the nuclear legacy in this region.

Drilling 1100-km-long seafloor ridges reveals how palaeoshorelines control carbonate shelf morphologies (North West Shelf, Australia)

The Rowley Shelf, the southern half of the tropical, carbonate-dominated, North West Shelf of Australia, is covered with linear ridges that can be tracked parallel to the coast over 1100 km between the modern coast and the 140 m isobath. Here, we investigate the origin and nature of these ridges based on the integration of extensive borehole data, high-resolution geophysical data, age dating and compaction analysis.Our investigation reveals that each ridge consists of now-submerged relict coastal deposits that were formed over the last 200,000 years through wave, tidal, fluvial and aeolian processes. These features were dominantly preserved through early diagenesis and illustrate the longest continuous submerged palaeoshorelines reported to date.The distribution of relict coastal features, and therefore early diagenesis, controls the morphology of the continental shelf. First, relict coastal features tend to be stacked on top of each other, resulting in the formation of composite diachronous coastal deposits that form distinctive steps on the seabed, up to 10s m high. Second, relict coastal features form a hard substrate that controls the location of coral reefs along the shelf. Reefs, including a 20-m-thick MIS 3 drowned coral reef described here for the first time, as well as modern reefs of the Muiron Islands, Montebello Islands and Dampier Archipelago, are all developed on top of relict coastal features.The distribution, size and mineralogy of relict coastal features highlight climatic changes along the Rowley Shelf. High relative sea levels (RSL) are associated with low carbonate production and up to 50% of terrigenous grains, while low RSL deposits exhibit increased carbonate production and reduced terrigenous grain content. This asymmetry is interpreted to reflect the onset of the monsoon associated with increased fluvial runoffs during interglacial periods.Lastly, our work shows that compaction analyses are critical for palaeoenvironment and RSL reconstructions. Indeed, the accumulation of 50 m of sediment on a RSL indicator can result in an offset of the measurement by 12.7 m.

Latitude, depth and environmental variables influence deepwater fish assemblages off Western Australia

Continental shelf and upper slope fishes are important global resources which have significant economic and biodiversity values. Understanding the drivers of their abundance and distribution are fundamental to guide sustainable fisheries management arrangements. Deepwater demersal fish assemblages were sampled between depths of 91–570 m at six locations along the Western Australian coastline spanning 17° of latitude (i.e. 17–34°S at the Rowley Shoals, Montebello Islands, Ningaloo Reef, Abrolhos Islands, Perth Canyon and South West Capes) using Baited Remote Underwater Stereo-Video systems (stereo-BRUVs, n = 417 deployments). A total of 5965 individual fishes were identified belonging to 252 species and 92 families. Assemblage composition data were modelled against in-situ habitat data, temperature, salinity, current speed, and current direction. Multivariate statistical analyses revealed that fish assemblage composition was predominantly influenced by latitude (9.5% of variation), depth (7.3%) and salinity (7.2%). Three distinct assemblages were defined in response to latitude; a tropical, a sub-tropical and a southern temperate bioregion. Species richness declined with increasing latitude, and average biomass was highest in the southern bioregion. A mid-depth peak in biomass and lengths indicated the dominance of meso-predator species in the 300–399 m depth range. The information provided by this study on the factors influencing the abundance and distribution of fish assemblages over an exceptionally broad depth and latitudinal range along a continuous coastline will be useful for predicting the effects of future climate shifts on this and similar teleost species occupying tropical and temperate oceans elsewhere.

Palaeoecology and sea level changes: Decline of mammal species richness during late Quaternary island formation in the Montebello Islands, north-western Australia

Palaeoecology and sea level changes: Decline of mammal species richness during late Quaternary island formation in the Montebello Islands, north-western Australia

Future migration: Key environmental indicators of Pu accumulation in terrestrial sediments of Queensland, Australia

Plutonium (Pu) interactions in the environment are highly complex. Site-specific variables play an integral role in determining the chemical and physical form of Pu, and its migration, bioavailability, and immobility. This paper aims to identify the key variables that can be used to highlight regions of radioecological sensitivity and guide remediation strategies in Australia. Plutonium is present in the Australian environment as a result of global fallout and the British nuclear testing program of 1952–1958 in central and west Australia (Maralinga and Montebello islands). We report the first systematic measurements of 239+240Pu and 238Pu activity concentrations in distal (≥1000 km from test sites) catchment outlet sediments from Queensland, Australia. The average 239+240Pu activity concentration was 0.29 mBq.g −1 (n = 73 samples) with a maximum of 4.88 mBq.g −1.238Pu/239+240Pu isotope ratios identified a large range (0.02–0.29 (RSD: 74%)) which is congruent with the heterogeneous nuclear material used for the British nuclear testing programme at Maralinga and Montebello Islands. The use of a modified PCA relying on non-linear distance correlation (dCorr) provided broader insight into the impact of environmental variables on the transport and migration of Pu in this soil system. Primary key environmental indicators of Pu presence were determined to be actinide/lanthanide/heavier transition metals, elevation, electrical conductivity (EC), CaO, SiO2, SO3, landform, geomorphology, land use, and climate explaining 81.7% of the variance of the system. Overall this highlighted that trace level Pu accumulations are associated with the coarse, refractive components of Australian soils, and are more likely regulated by the climate of the region and overall soil type.

Radionuclides in sea turtles at the Montebello Islands former nuclear test sites: Current and historical dose rates for adults and embryos

Radionuclides from 1950s weapons testing at the Montebello Islands, Western Australia, may impact sea turtle embryos incubating within eggs laid in contaminated sands or be taken up into adult body tissues where they can contribute to radiation dose over a turtles' 60+ year lifespan. We measured plutonium in all local samples including turtle skin, bones, hatchlings, eggshells, sea sediments, diet items and beach sands. The amount of Pu in developing embryos/hatchling samples was orders of magnitude lower than that in the surrounding sands. These contaminated sands caused most dose to eggs (external dose from 137Cs, 152Eu), while most of the dose to adults was from internalised radionuclides (98%). While current dose rates are relatively low, local dose rates were high for about ten years following the 1950s detonations and may have resulted in lethality or health impacts to a generation of turtles that likely carry biomarkers today.

Verifying the extent of plumes from produced formation water: a Wheatstone case study

Chevron Australia Pty Ltd operates the Wheatstone liquefied natural gas facility in Western Australia under a Joint Operating agreement. Hydrocarbons from Wheatstone, Iago and Julimar-Brunello fields are sent to the Wheatstone Platform (the Platform), located ~50 km north of the Montebello Islands, for dewatering and dehydration before being transported onshore for final processing. Produced formation water (PW) is processed (treated) and, once criteria are met, discharged overboard. PW at Wheatstone is predicted to rapidly dilute in the receiving ocean to concentrations below water quality criteria (Australian and New Zealand Environment Conservation Council guidelines and ecotoxicology), though empirical evidence is needed to verify the actual discharge risk. Seawater (i.e. cooling water, CW) is also abstracted for cooling duty on the Platform, chlorinated and discharged. This paper describes a field verification campaign aimed at understanding PW and CW behaviour in the water column post-discharge, dilution with distance and whether numerical modelling of dilutions is accurate. The campaign was designed to evaluate plume characteristics by monitoring both entrained PW constituents (i.e. hydrocarbons and metals) and using a Rhodamine WT tracer dye. Monitoring of these constituents was done using an array of sampling techniques, including fluorometry, remotely operated vehicles and discrete water samplers. Results indicate rapid dilutions post PW and CW discharge, with dye fluorometry proving a valuable tool for understanding plume characteristics. Water sampling data interpretation indicated dilutions were likely orders of magnitude greater than anticipated, likely due to variable flow effects and turbulence induced by the Platform structure for PW, and the influence of entrained air within the plume for CW.

Plutonium and other radionuclides persist across marine-to-terrestrial ecotopes in the Montebello Islands sixty years after nuclear tests.

Since the 1956 completion of nuclear testing at the Montebello Islands, Western Australia, this remote uninhabited island group has been relatively undisturbed (no major remediations) and currently functions as high-value marine and terrestrial habitat within the Montebello/Barrow Islands Marine Conservation Reserves. The former weapons testing sites, therefore, provide a unique opportunity for assessing the fate and behaviour of Anthropocene radionuclides subjected to natural processes across a range of shallow-marine to island-terrestrial ecological units (ecotopes). We collected soil, sediment and biota samples and analysed their radionuclide content using gamma and alpha spectrometry, photostimulated luminescence autoradiography and accelerator mass spectrometry. We found the activity levels of the fission and neutron-activation products have decreased by ~hundred-fold near the ground zero locations. However, Pu concentrations remain elevated, some of which are high relative to most other Australian and international sites (up to 25,050 Bq kg-1 of 239+240+241Pu). Across ecotopes, Pu ranked from highest to lowest in the following order: island soils > dunes > foredunes > marine sediments > and beach intertidal zone. Low values of Pu and other radionuclides were detected in all local wildlife tested including endangered species. Activity concentrations ranked (highest to lowest) terrestrial arthropods > terrestrial mammal and reptile bones > algae > oyster flesh > whole crab > sea turtle bone > stingray and teleost fish livers > sea cucumber flesh > sea turtle skin > teleost fish muscle. The three detonations (one from within a ship and two from 30 m towers) resulted in differing contaminant forms, with the ship detonation producing the highest activity concentrations and finer more inhalable particulate forms. The three sites are distinct in their 240/239Pu and 241/239Pu atom ratios, including the Pu transported by natural process or within migratory living organisms.

Crown-of-thorns starfish impede the recovery potential of coral reefs following bleaching

High densities of the corallivorous crown-of-thorns starfish (CoTS; Acanthaster sp.) have occurred throughout the Indo-Pacific often resulting in widespread coral loss. Whilst CoTS have previously been recorded at Barrow and the Montebello Islands, in the Pilbara offshore bioregion of northwestern Australia, their densities were relatively low. Outbreak densities of CoTS have been described as the level at which the rate of coral consumption by the starfish is equal to or greater than rate at which the coral grows. In 2014, we recorded densities as high as 320 ± 58 CoTS ha−1 in the region which is well above recognised outbreak densities. Whilst there is little terrestrial runoff and agriculture in the Pilbara region, both temperature and chlorophyll-α levels appear to be sufficient to allow a high degree of CoTS larval success in most years. The region was subjected to anomalously high water temperatures during the summers of 2010–2011 and particularly 2012–2013 which resulted in the mortality of almost 70% of live coral. We hypothesise that the high densities of CoTS observed are a result of CoTS responding to a reduced food supply and aggregating around the remaining live coral resulting in outbreak densities rather than a significant increase in the number of CoTS in the area. The small amount of remaining live coral is concentrated in a few areas and this, combined with high densities of CoTS in these areas, suggest that CoTS represent a significant threat to the recovery of the coral communities of the region.

Records of Australian humpback dolphins (Sousa sahulensis) from an offshore island group in Western Australia

We report records of humpback dolphins at the Montebello Islands (20°26’S, 115°33′E) approximately 80 km from the mainland coast of Western Australia. This island group is a marine protected area (MPA), with approximately half of the area a sanctuary (no take) zone managed solely for nature conservation that excludes activities such as fishing and resource extraction, activities known to impact dolphins elsewhere. The habitat varies but includes fringing coral reef and shallow, sheltered sandy lagoons mostly < 10 m water depth and not exceeding 20 m. Several opportunistic sightings and one targeted five-day survey have resulted in 28 dolphins being catalogued in the MPA through photo-identification of natural marks on the dorsal fin and are considered to be recognisable through either distinctive or subtle marks. The species was initially reported in the MPA in June 2015 and was present in summer, autumn and winter of 2017. Six calves have been observed in the MPA, with one a neonate. Given the recent listing of the species as Vulnerable on the IUCN Redlist, and increasing pressure on near-shore coastal habitat, recognising the presence of this species at offshore islands such as these, and understanding their status and connectivity is a priority for the conservation and management of the species in Western Australia.

Bottom currents and sediment waves on a shallow carbonate shelf, Northern Carnarvon Basin, Australia

The modern seafloor of the Australian Northwest Shelf between Exmouth and Dampier was analyzed for large scale sedimentary bedforms on 3D seismic reflection data. The Carnarvon MegaSurvey of Petroleum Geo-Services (PGS), a merged dataset of multiple industrial 3D seismic reflection surveys with a total size of 49,717km2, offers an extensive view of the continental shelf, slope and rise of the Northern Carnarvon Basin. Over the shelf two fields of large scale sediment waves were observed in water depths between 55–130m, where the seafloor may be influenced by different processes including internal waves, tides and storms. Based on the dimensions and orientations of the sediment waves the dominant direction and approximate strength of local bottom currents could be estimated. Information on local sediment grain-size distribution was provided by the auSEABED database allowing a classification of the observed sediment waves into sand- or mudwaves. The first sediment wave field is positioned northwest of the Montebello Islands where the shelf is comparatively narrow and local sediment is mainly sand-sized. It most likely formed by increased bottom currents induced by the diversion of tidal flows around the islands. The second sediment wave field is located north of the Serrurier and Bessieres Islands within a local seafloor depression. Local sediments are poorly sorted, containing significant amounts of mud and gravel in addition to the mainly sand-sized grains. The coarser sediment fraction could have been reworked to sandwaves by cyclone-induced bottom currents. Alternatively, the finer sediment fraction could form mudwaves shaped by less energetic along-slope oriented currents in the topographic depression. The sediment waves consist partially of carbonate grains such as ooids and peloids that formed in shallow water during initial stages of the post glacial sea-level rise. These stranded carbonate grains thus formed in a different environment than the sediment waves in which they were redeposited. In fossil examples of similar high-energy ramp systems this possible out-of-equilibrium relationship between grains and bedforms has to be taken into account for the interpretation of the depositional environment.

Plectorhinchus caeruleonothus, a new species of sweetlips (Perciformes: Haemulidae) from northern Australia and the resurrection of P. unicolor (Macleay, 1883), species previously confused with P. schotaf (Forsskål, 1775).

Two distinct haemulid fishes from Australia and the Indo-Australian Archipelago respectively have long been confused with Plectorhinchus schotaf (Forsskål, 1775). Plectorhinchus caeruleonothus sp. nov. is described from 17 specimens collected off western and far northern Australia, between the Monte Bello Islands, Western Australia and Torres Strait, Queensland. It has also been confirmed outside this range by photographs taken at Ningaloo Reef and Exmouth Gulf, Western Australia, and at Claremont Isles and Lizard Island, Queensland. The new species is unique among the genus in having a combination of dorsal-fin rays XII, 18-20, lateral-line scales 56-61, gill rakers 7-9 on the upper limb and 18-20 on the lower limb of the first arch, nostrils minute, and fresh colouration in adults including body uniformly grey, cheek, opercles and posterior margin of the opercular membrane uniformly blue-grey, and rim of orbit and upper edge of maxilla dusky yellow. In contrast to its closest congeners, the juveniles have a distinctive pattern of narrow creamish-white to pale grey stripes on a dark grey to chocolate brown background on the head and body, and oblique dark stripes progressing with growth to spots on the caudal fin. Plectorhinchus unicolor (Macleay, 1883) from Japan to northern Australia is resurrected from the synonomy of P. schotaf and redescribed on the basis of the holotype and 24 non-type specimens. Plectorhinchus unicolor is most similar to P. schotaf, but can be distinguished by fresh colouration, modal dorsal and pectoral-fin ray counts and DNA barcoding. Plectorhinchus schotaf appears to be restricted to the region from southeast Africa to the Arabian Sea, including the Red Sea and Persian Gulf. Plectorhinchus griseus (Cuvier in Cuvier & Valenciennes, 1830) from Indian and Sri Lankan Seas has previously been treated as a junior synonym of P. schotaf, but in accordance with Smith (1962), is here confirmed as a valid species, readily distinguished from the latter by a concavity in the lateral profile of the snout in adults, deep body and high soft dorsal-fin ray count. Comparison of the CO1 genetic marker utilised in DNA barcoding also resulted in significant genetic divergences between the new species, P. unicolor and their closest sampled congeners. Some behavioural observations are also presented for the species treated, including aggressive interactions between individuals of the new species, the likes of which have not previously been recorded among species of Plectorhinchus.

Late Pleistocene and early Holocene exploitation of estuarine communities in northwestern Australia

This contribution synthesizes archaeological studies of human economies from the Barrow–Montebello islands and uses the area's archaeological record to determine the effects of Late Pleistocene and early Holocene sea-level rise on regional coastlines. At the height of the Last Glacial Maximum (LGM), Australia's north-western coast extended much further west than the present-day shoreline. During subsequent sea-level rise, the gently prograding continental shelf was inundated, and with it, nearly all archaeological evidence for coastal occupation. The Barrow and Montebello Islands are one of the few exceptions, as they corresponded to inland hinterland ranges during the LGM, with the coastline lying some 50 km to their west. Evidence from all late Pleistocene and Holocene occupation phases of the Barrow–Montebello Islands demonstrate that foragers continued to visit the coast and engage in the exploitation of both terrestrial and marine environments. During the late Pleistocene, when the shoreline was 10–15 km away, coastal exploitation is seen through the presence of transportable estuarine and rocky-shore gastropods. By the early Holocene, when sea-levels were within close proximity of the sites, there is a marked increase in marine fauna including reef fish, estuarine and reef shellfish, crustaceans and estuarine crocodile. Together, this suggests that the nearby muddy, procumbent coastlines were productive, as well as an important component of coastal and hinterland economies.

Remotely Monitoring Change in Vegetation Cover on the Montebello Islands, Western Australia, in Response to Introduced Rodent Eradication

The Montebello archipelago consists of 218 islands; 80 km from the north-west coast of Western Australia. Before 1912 the islands had a diverse terrestrial fauna. By 1952 several species were locally extinct. Between 1996 and 2011 rodents and cats were eradicated, and 5 mammal and 2 bird species were translocated to the islands. Monitoring of the broader terrestrial ecosystem over time has been limited. We used 20 dry-season Landsat images from 1988 to 2013 and estimation of green fraction cover in nadir photographs taken at 27 sites within the Montebello islands and six sites on Thevenard Island to assess change in vegetation density over time. Analysis of data averaged across the 26-year period suggests that 719 ha out of 2169 ha have increased in vegetation cover by up to 32%, 955 ha have remained stable and 0.6 ha have declined in vegetation cover. Over 492 ha (22%) had no vegetation cover at any time during the period analysed. Chronological clustering analysis identified two breakpoints in the average vegetation cover data occurring in 1997 and 2003, near the beginning and end of the rodent eradication activities. On many islands vegetation cover was declining prior to 1996 but increased after rodents were eradicated from the islands. Data for North West and Trimouille islands were analysed independently because of the potential confounding effect of native fauna being introduced to these islands. Mala (Lagorchestes hirsutus) and Shark Bay mice (Pseudomys fieldi) both appear to suppress native plant recruitment but not to the same degree as introduced rodents. Future research should assess whether the increase in vegetation cover on the Montebello islands is due to an increase in native or introduced plants.

Maritime deserts of the Australian northwest

This paper reports on the first season of work on the Barrow Island Archaeology Project. It contextualises new findings within a review of what is now known of the archaeology of the Carnarvon bioregion. A reliance on coastal resources for over 42,000 years is indicated from excavations and open sites from Cape Range, the Montebello Islands, the Onslow coastline and Barrow Island. The continuous use of marine resources, blended with largely arid zone terrestrial assemblages, from 17,000 cal. BP until the modern era, attests to a deep chronology for hybrid maritime desert societies in the Australian northwest.

Operation TIGRESS: deception for counterintelligence and Britain’s 1952 atomic test

Britain tested its first atomic weapon on the Montebello islands, off Western Australia, in October 1952. This test, known as HURRICANE, was supported by an elaborate deception operation, one designed to deceive the Soviets about the date and the true nature of the test. This article examines this deception. It introduces Britain’s post-war deception organisations, the London Controlling Section, later the Directorate of Forward Plans, and how they worked closely with Britain’s atomic scientists from early in the Cold War. Their plans were complicated both by the Soviets’ success in gathering intelligence on Britain’s nuclear programme, and by the West’s difficulty in gathering intelligence on Soviet dispositions. Nevertheless, they utilised a broad range of channels, both open and secret, to implement their scheme. The manner in which they operated suggests that the deception and intelligence machinery had clearly adapted their methods to the Cold War environment, but that the task was considerably more difficult than the one they faced in wartime.

Sacrificial Experts? Science, Senescence and Saving the British Nuclear Project

This essay is an enquiry into the roles scientists and engineers might make for themselves in an aging society. At its centre is a case study of an extraordinary response to a devastating event: a British project after Chernobyl to set up a cadre of volunteers, aged 65 or over, willing to act swiftly, expertly and, perhaps, expendably, in the wake of a nuclear emergency. Surprisingly obscure now, the would-be volunteers included many of the elite of British science and engineering. The episode is fascinating on many levels and invites several different analytical perspectives, which I will explore. However, the dimension that interests me most concerns primarily old age. Most obviously, the project mobilised an elderly population of elite experts, who felt themselves to be both qualified and occasionally disqualified to act because of their age. The project prompted them to reflect, soberly and insightfully, on the qualities and capacities of aged scientists and engineers, sometimes as self-reflection as individuals, sometimes as a group with identifiable characteristics. But there are other, just as interesting dimensions of age raised in the project. In particular, this generation felt responsible and protective over its achievements, not least the nuclear programmes of the second half of the twentieth century, and were willing to exchange physical jeopardy to secure its continuation.Furthermore, there is a dynamic social context to aging within which the generation who reached their 60s in the 1980s must be located: an aging society in which what it was to be old was changing both quantitatively and qualitatively. In terms of simple numbers more people in the West were living far beyond the traditional life span of three score and ten. Qualitatively, the period was marked by the articulation of ideas of a old age, a 'Third Age of activity before senescence, and a gerontological interest in successful aging. A proportion of the elderly are now seen as resilient, healthy, keen to stay in employment or to continue to be involved in social and community matters.1 A final twist that makes the examination of scientists and engineers attempt to carve out new roles in an aging society particularly meaningful is that this extension of life, in both senses, was seen as a product of scientific intervention.2EXPERTS, EXPERTISE AND THE BRITISH NUCLEAR PROJECTBritish involvement in nuclear weapon and power projects began during the Second World War. Following the calculations of the critical mass necessary to generate a chain reaction of uranium fission by the emigres Otto Frisch and Rudolf Peierls, working at the University of Birmingham, in 1940 the UK government set up the MAUD committee to establish the feasibility of an atomic bomb.3 As is well known, British efforts, beginning with the arrival in 1 943 of nineteen scientists at Los Alamos, were soon drawn in to the Manhattan Project. In December 1945, four months after Hiroshima and Nagasaki, prime minister Clement Attlee's GEN 75 Cabinet Committee on Atomic Energy, authorised the construction of an atomic reactor at Windscale on the Cumbrian coast. The aim was to produce plutonium. In 1946, the McMahon Act in the United States superseded previous UK-US agreements on the sharing of nuclear knowledge and responsibilities, and prohibited further transfer of information. Previously sceptical views (on economic grounds) in the British Cabinet were sidelined, and commitments made in 1946 and 1947 to complete a British nuclear bomb and to expand necessary research and development work. The institutional landscape of the British nuclear project was filled out, including the Atomic Energy Research Establishment at Harwell, the Atomic Weapons Research Establishment at Aldermaston, and a nuclear factory at Windscale. A British atomic bomb was first tested on the Monte Bello islands, Australia, in October 1952.The 1950s witnessed further institutionalisation and expansion of the British nuclear projects. …

Plutonium and uranium contamination in soils from former nuclear weapon test sites in Australia

The British government performed a number of nuclear weapon tests on Australian territory from 1952 through to 1963 with the cooperation of the Australian government. Nine fission bombs were detonated in South Australia at Emu Junction and Maralinga, and a further three fission weapons were detonated in the Monte Bello Islands off the coast of Western Australia. A number of soil samples were collected by the Australian Radiation Laboratories in 1972 and 1978 during field surveys at these nuclear weapon test sites. They were analysed by gamma spectrometry and, for a select few samples, by alpha spectrometry to measure the remaining activities of fission products, activation products and weapon materials. We have remeasured a number of these Montebello Islands and Emu Junction soil samples using the ANTARES AMS facility, ANSTO. These samples were analysed for plutonium and uranium isotopic ratios and isotopic concentrations. Very low 240Pu/239Pu ratios were measured at both sites (∼0.05 for Alpha Island and ∼0.02 for Emu Field), substantially below global fallout averages. Well correlated but widely varying 236U and plutonium concentrations were measured across both sites, but 233U did not correlate with these other isotopes and instead showed correlation with distance from ground zero, indicating in situ production in the soils.

Pseudopataecus carnatobarbatus, a new species of velvetfish (Teleostei: Scorpaeniformes: Aploactinidae) from the Kimberley coast of Western Australia

Pseudopataecus carnatobarbatus, new species, is described from 12 specimens collected on shallow coastal reefs of northernWestern Australia, between the Monte Bello Islands and Adele Island. It is distinguished from its sole congener, P. taenianotusJohnson 2004, by branched (versus simple) tips to most fin rays, last soft dorsal-fin ray joined by membrane more fully toupper caudal-fin ray, spinous dorsal fin more distinctly notched, pelvic fins more robust, anterior face of lower lip smooth (ver-sus profusely covered with cirri), and a narrow quadrangular pit on the forehead, bounded by frontal, supraorbital, ocular andpreocular ridges (versus pit and preocular ridge absent). It also has modally fewer anal-fin rays and modally greater numbers ofgill rakers. Pseudopataecus carnatobarbatus is found in an extremely high tidal range area of Australia, where movement of upto 11 m occurs during spring tides. Specimens were collected in rocky tide pools with coral rubble and thick stands of brownmacroalgae, especially Padina species. The new species has been found in intertidal areas up to only 13 m deep, whereas P. taenianotus has been collected by trawling soft bottom habitats in depths of 20 to 63 m.

Molecular characterisation of a haplosporidian parasite infecting rock oysters Saccostrea cuccullata in north Western Australia

A haplosporidian parasite was identified in rock oysters ( Saccostrea cuccullata Born, 1778) from the Montebello Islands (latitude −20.4′S longitude 115.53′E) off the northern coast of Western Australia by histopathological examination, PCR amplification and DNA sequencing of a segment of the SSU region of the parasite’s rRNA gene. An oligonucleotide probe was constructed from the parasite’s SSU rRNA gene in order to confirm its presence by in situ hybridisation. The parasite was disseminated throughout the gonad follicles of the host and to a lesser extent in the gills. The only parasite life stages thus far observed in this study were a uninucleate naked cell assumed to be a precursor to multinucleate plasmodial stages and a binucleate plasmodial stage. Whilst no parasite spores were detected in affected rock oysters, a phylogenetic analysis of the SSU region of the parasite’s rRNA gene indicates the parasite belongs to the genus Minchinia. A PCR and in situ hybridisation assay for the Minchinia sp. was used to identify haplosporidians described by Hine and Thorne [Hine, P.M.., Thorne, T., 2002. Haplosporidium sp. (Haplosporidia: Haplosporidiidae) associated with mortalities among rock oysters Saccostrea cuccullata in north Western Australia. Dis. Aquat. Organ. 51, 123–13], in archived rock oyster tissues from the same coastline.