Princess Charlotte Bay Research Articles

Impact of a Tropical Cyclone on Terrestrial Inputs and Bio-Optical Properties in Princess Charlotte Bay (Great Barrier Reef Lagoon)

In January 2013, tropical cyclone Oswald caused widespread flooding in the North-East coast of Australia, and large and highly episodic inputs into Princess Charlotte Bay (PCB, northern Great Barrier Reef). Freshwater outflows from the Normanby and Kennedy rivers, the two main rivers draining the adjacent catchments, resulted in drastic changes in physical, biogeochemical and optical properties within PCB. On 31 January, 2 days after the peak riverine discharge from the Normanby river, nutrients and dissolved organic matter contents peaked under the influence of large outflows from the Kennedy river into the western section of the bay (5.8 μM for dissolved inorganic nitrogen, 6.9 g m−3 for dissolved organic carbon and 6.1 m−1 for the colored dissolved organic matter absorption coefficient at 412 nm). In the eastern section of the bay, the situation appeared more ‘mixed’, with a suspended solids concentration reaching 23.1 g m−3 close to the Normanby river mouth. The main phytoplankton bloom occurred in the transition zone between the Kennedy and Normanby flood plumes, and was dominated by diatoms with a chlorophyll a concentration reaching 14.6 mg m−3. This study highlights the need to better describe the critical spatial and temporal scales of variability of key biogeochemical and optical properties after a major flood event. The data collected is key to improve the accuracy of ocean color remote sensing algorithms and regional biogeochemical budgets following highly episodic inputs.

Controls on Carbon, Nutrient, and Sediment Cycling in a Large, Semiarid Estuarine System; Princess Charlotte Bay, Australia

AbstractSemiarid estuaries are characterized by pronounced seasonal variability, and a functional understanding of these systems requires constraint of coupled biogeochemical processes and relevant temporal and spatial scales. Here, we integrate 2 years of spatial surveys and time‐series measurements to quantify physical, chemical, and biological drivers in the largest estuarine system in the Great Barrier Reef region. During wet season, freshwater inputs of nutrients and sediment to estuaries were dominated by flood pulses, whereas carbonate input was also influenced by groundwater discharge. This carbonate input counteracted the minimum buffering zone that would otherwise occur at low salinities, thereby decreasing system‐wide air‐water CO2 fluxes. Sediment resuspension was a major control on the transformation and transport of material over tidal and seasonal scales. During wet season, tidal resuspension of benthic algae in nearshore mixing zones acted as an autotrophic filter, removing most bioavailable nutrients from the brackish plume. During dry season, upstream transport combined with hypersaline conditions trapped material in upper estuaries where denitrification and net heterotrophy were high. However, the role of sediment transport varied depending on tidal asymmetry and density‐driven circulation. Estuarine regions with large intertidal areas were dominated by salt flat erosion, which showed a diagenetic signature associated with mid‐Holocene swamp sediments. Tidal resuspension of these organic‐rich sediments appeared to be the dominant control on biogeochemical cycling in coastal waters. This study demonstrates that a holistic understanding of coastal ecosystem connectivity and function requires resolution of both along‐axis and water‐column gradients as well as a range of timescales from tidal to geological cycles.

Mbarrumbathama (Lamalama)

Mbarrumbathama is a clan-named variety of Lamalama, a language of Cape York Peninsula, in the northeast of Australia. Together with Umbuygamu (Ogilvie 1994, Sommer 1998, Verstraete 2017) and Rimanggudinhma (Godman 1993), Lamalama forms the Lamalamic subgroup of Paman languages (Laycock 1969, Rigsby 1997, Verstraete 2018), themselves a subgroup of Pama-Nyungan (Hale 1964, 1966; see also Bowern & Atkinson 2012). The language is no longer spoken, but it is traditionally associated with about 20 clans (as reconstructed by Rigsby 1999, 2014) belonging to the southern shores of Princess Charlotte Bay, on the east coast of Cape York Peninsula (see Figure 1). The clans’ estates are mainly coastal, extending from the Normanby River mouth in the east to about 10 km west of the North Kennedy River mouth, but they also include some inland estates (see Rigsby 1992: 356).

Assessment of water quality from the Normanby River catchment to coastal flood plumes on the northern Great Barrier Reef, Australia

Understanding the flux and fate of nutrients and sediments from rivers is of global importance because of the effects of these materials on coastal ecosystems. The present study followed three flood events from upper tributaries of the Normanby River to Princess Charlotte Bay in the northern Great Barrier Reef (GBR) lagoon, Australia. During each event, nutrients and suspended sediment concentrations were measured along a freshwater to marine transect. The upper catchment provided the majority of suspended sediments and nutrients supplied to the river system, although concentrations of most materials decreased by 52–85% between the upper catchment and estuary. As an exception, ammonium concentrations doubled within the estuary, indicating that undisturbed coastal ecosystems can provide a significant source of dissolved inorganic nitrogen to tropical river flood plumes. The dissolved nutrients in floodwaters stimulated phytoplankton blooms that inundated seagrass meadows and coral reefs. Northern GBR marine ecosystems are increasingly threatened by climate change and catchment development. The results of this study show that increased anthropogenic loads of nutrients and sediments from the upper Normanby catchment have the potential to affect the condition of marine ecosystems at Princess Charlotte Bay.

Are there two species of Graceful Honeyeater in Australia?

Two subspecies of Graceful Honeyeater Meliphaga ( Microptilotis ) gracilis are recognised in north-eastern Queensland: imitatrix inhabiting the Wet Tropics and gracilis inhabiting northern Cape York Peninsula. Vocalisations differ greatly between the two, so the strong possibility emerges that they are distinct species. The ranges of these taxa are separated by ~140 km in the vicinity of Cape Flattery–Princess Charlotte Bay on the eastern coast of Cape York Peninsula. Significantly, a thorough search confirms that there have been no specimens collected from this geographical gap between the two populations and previously suspected intergradation does not occur. This paper describes the considerable differences between the two, especially with respect to vocalisations, and suggests that these taxa represent distinct species.

Umbuygamu

Umbuygamu is a Pama-Nyungan language of the east coast of Cape York Peninsula, in the northeast of Australia. Genetically, the language belongs to the Lamalamic subgroup (Laycock 1969, Rigsby 1997) of Paman languages, themselves a subgroup of Pama-Nyungan (as proposed by Hale 1964, 1966; see also Bowern & Atkinson 2012). Umbuygamu is the language of three clans at the southern end of Princess Charlotte Bay, about halfway up the east coast of Cape York Peninsula. Their estates are centred on a lagoon called Emanha (or Dinner Hole in English); they extend inland into the upper Running Creek system, and include the Cliff Islands group along the coast; see Rigsby 1992 for more details, and Verstraete & Rigsby (2015: 2) for a map of the region and its languages. Neighbouring languages are the Middle Paman language Umpithamu, along the coast to the north (see, for instance, Verstraete 2010, 2012) and two Lamalamic languages, Rimanggudinhma to the southwest (located inland; Godman 1993, Sommer 1999b), and Lamalama to the southeast (along the coast; Sommer 1999a).

Macroscopic approaches to the identification of expedient bivalve tools: A case study investigating Polymesoda (=Geloina) coaxans (Bivalvia: Corbiculidae) shell valves from Princess Charlotte Bay, Queensland, Australia

The identification of expedient bivalve tools recovered from archaeological deposits is currently hindered by a lack of analytical frameworks. In order to identify those shell valves which have been used as expedient tools, analysts must be able to identify and distinguish between pre-mortem and post-depositional modifications, and use-wear from tool use. Central to this difficulty is a lack of experimental analogues for comparison with archaeological material. Here, we present an analytical framework for the identification of expedient bivalve tools made from Polymesoda (=Geloina) coaxans valves recovered from Australian archaeological sites. This analytical framework consists of a series of actualistic experiments designed to determine those variables useful for distinguishing between modifications produced via pre-mortem and post-depositional processes that can damage molluscan shell, and damage produced via use as an expedient tool. Trampling, flaking and scraping experiments and use-wear analysis are used as a reference for comparison with an assemblage of P. coaxans valves recovered from archaeological sites in Princess Charlotte Bay, north Queensland, Australia. We demonstrate that an analytical framework consisting of an analysis of shell area loss, shell fracture paths, and use-wear can be successfully applied to archaeological samples to confidently distinguish between those valves which have been used as expedient tools, and those which have not. This research has wider implications for the identification of this often overlooked class of shell tools from archaeological sites in Australia and other regions, allowing a more comprehensive understanding of the place of shell tools in coastal economies of the past.

The development of the Princess Charlotte Bay chenier plain: New results and insights

Abstract Chenier plains record changes in the mode of coastal progradation between periods of mudflat accumulation and coarse sediment deposition. The geomorphic development of the Princess Charlotte Bay chenier plain was last considered in the 1980s and the conclusions have contributed to knowledge of muddy coastal morphodynamics. Obtaining new data through the use of luminescence dating techniques provided an opportunity to reassess previous findings. Data were obtained from the south western portion of the bay where the chenier ridges were most distinct whereas previous research had been concentrated on the far eastern periphery of the plain. Optically-stimulated luminescence age estimates and radiocarbon ages from eight of the 11 most seaward chenier ridges yielded a new depositional chronology. The recent chenier sequence in this area began forming with the establishment of the most landward chenier ridge (ridge 1) no more than 4000 yr BP. In the ~ 1500 years following this, two more chenier ridges were built (ridges 2 and 3, which were not sampled). Ridge 4 was being built at around 2400 yr BP, ridges 5 and 6 at around 2100 yr BP, ridge 7 at around 1900 yr BP, ridges 8 and 9 at around 1300 yr BP, ridge 10 (which was not dated) between 1300 and 820 yr BP, and ridge 11 at around 820 cal yr BP. Comparing the new data to previous data and conclusions yielded new insights into the Holocene development of the chenier plain. These new insights may provide a means for Australian chenier plains to inform contemporary coastal morphodynamics more broadly.

Age, distribution, and significance within a sediment budget, of in-channel depositional surfaces in the Normanby River, Queensland, Australia

We present the results of investigations into alluvial deposition in the catchment of the Normanby River, which flows into Princess Charlotte Bay (PCB) in the northern part of the Great Barrier Reef Lagoon. Our focus is on the fine fraction (<~63μm) of alluvial deposits that sit above the sand and gravel bars of the channel floor, but below the expansive flat surface generally referred to as the floodplain. Variously described as benches, bank attached bars or inset or inner floodplains, these more or less flat-lying surfaces within the macro-channel have hitherto received little attention in sediment budgeting models. We use high resolution LiDAR based mapping combined with optical dating of exposures cut into these in-channel deposits to compare their aggradation rates with those found in other depositional zones in the catchment, namely the floodplain and coastal plain. In total 59 single grain OSL dates were produced across 21 stratigraphic profiles at 14 sites distributed though the 24226km2 catchment. In-channel storage in these inset features is a significant component of the contemporary fine sediment budget (i.e. recent decades/last century), annually equivalent to more than 50% of the volume entering the channel network from hillslopes and subsoil sources. Therefore, at the very least, in-channel storage of fine material needs to be incorporated into sediment budgeting exercises. Furthermore, deposition within the channel has occurred in multiple locations coincident in time with accelerated sediment production following European settlement. Generally, this has occurred on a subset of the features we have examined here, namely linear bench features low in the channel. This suggests that accelerated aggradation on in-channel depositional surfaces has been in part a response to accelerated erosion within the catchment. The entire contribution of ~370 kilotonnes per annum of fine sediment estimated to have been produced by alluvial gully erosion over the last ~100years can be accounted for by that stored as in-channel alluvium. These features therefore can play an important role in mitigating the impact on the receiving water of accelerated erosion.

Subsoil erosion dominates the supply of fine sediment to rivers draining into Princess Charlotte Bay, Australia

The Laura–Normanby River (catchment area: 24,350 km2), which drains into Princess Charlotte Bay, has been identified in previous studies as the third largest contributor of sediment to the Great Barrier Reef World Heritage Area. These catchment scale modelling studies also identified surface soil erosion as supplying >80% of the sediment. Here we use activity concentrations of the fallout radionuclides 137Cs and 210Pbex to test the hypothesis that surface soil erosion dominates the supply of fine (<10 μm) sediment in the river systems draining into Princess Charlotte Bay. Our results contradict these previous studies, and are consistent with channel and gully erosion being the dominant source of fine sediment in this catchment. The hypothesis that surface soil erosion dominates the supply of fine sediment to Princess Charlotte Bay is rejected. River sediment samples were collected using both time-integrated samplers and sediment drape deposits. We show that there is no detectable difference in 137Cs and 210Pbex activity concentrations between samples collected using these two methods. Two methods were also used to collect samples to characterise 137Cs and 210Pbex concentrations in sediment derived from surface soil erosion; sampling of surface-wash deposits and deployment of surface runoff traps that collected samples during rain events. While there was no difference in the 137Cs activity concentrations for samples collected using these two methods, 210Pbex activity concentrations were significantly higher in the samples collected using the runoff traps. The higher 210Pbex concentrations are shown to be correlated with loss-on-ignition (r2 = 0.79) and therefore are likely to be related to higher organic concentrations in the runoff trap samples. As a result of these differences we use a three end member mixing model (channel/gully, hillslope surface-wash and hillslope runoff traps) to determine the relative contribution from surface soil erosion. Probability distributions for 137Cs and 210Pbex concentrations were determined for each of the end members, with these distributions then used to estimate the surface soil contribution to each of the collected river sediment samples. The mean estimate of contribution of surface derived sediment for all river samples (n = 70) is 16 ± 2%. This study reinforces the importance of testing model predictions before they are used to target investment in remedial action and adds to the body of evidence that the primary source of sediment delivered to tropical river systems is derived from subsoil erosion.

Stock structure of blue threadfin Eleutheronema tetradactylum on the Queensland east coast, as determined by parasites and conventional tagging

Blue threadfin Eleutheronema tetradactylum (Polynemidae) were examined from four areas (Princess Charlotte Bay, Trinity Inlet, Halifax Bay and Upstart Bay) in eastern Queensland covering a distance of c. 950 km of coastline. Parasites were used as biological markers to infer stock structure of E. tetradactylum. Parasites designated as 'temporary' biological markers were the copepod Thysanote eleutheronemi, the acanthocephalan Neoechinorhynchus topseyi, the nematode Philometra rajani and hemiurid trematodes. The larval nematodes Anisakis sp. Type 1 and Terranova sp. Type 2; and the larval cestodes Pterobothrium pearsoni and Callitetrarhynchus gracilis were considered 'permanent' biological markers. Both univariate and multivariate analyses demonstrated that there was little difference in temporary parasite abundance between the four areas. In contrast, the same analyses revealed that most areas had two or more significant differences in permanent parasite abundance, with the exception of Halifax Bay and Upstart Bay, which were significantly different only in the multivariate analysis. Biological markers predicted that Princess Charlotte Bay and Trinity Inlet consisted of distinct populations, whereas Halifax Bay and Upstart Bay were not clearly differentiated. Tag recapture data supported this hypothesis; the majority of recaptures were within 100 km of the initial tagging location. Geographical movement of E. tetradactylum may be limited due to their biology and ecology, as well as the distances and oceanographic boundaries that separate habitats. Contrary to current management definitions, the stock structure of E. tetradactylum on the east coast of Queensland appears to be geographically differentiated at a small spatial scale.

Short-term climate variability and the commercial barramundi (Lates calcarifer) fishery of north-east Queensland, Australia

The sustainable productivity of estuarine fisheries worldwide is threatened by over-fishing, habitat destruction and water impoundment. In some cases, the natural variability of freshwater inputs has been shown to affect catch when low flows reduce nutrient input and inundated nursery habitats. Historically, the annual commercial catch of barramundi (Lates calcarifer) in Queensland has been highly variable for reasons not fully understood. In conjunction with a life-cycle model, statistical analyses of climate variables and barramundi catch data from the Princess Charlotte Bay area identified several significant relationships. Warm sea surface temperatures, high rainfall, increased freshwater flow and low evaporation (all measures of an extensive and productive nursery habitat) were significantly correlated with barramundi catch 2 years later and suggest that young barramundi survival is enhanced under these conditions. Catchability was significantly increased with high freshwater flow and rainfall events in the year of catch. A forward stepwise ridge regression model that included a measure of rainfall and evaporation 2 years before catch explained 62% of the variance in catch adjusted for effort. It is recommended that the impact of climate variability be considered in the management of wild barramundi stocks and possibly other species not yet examined.

A new species of Ostracoda from Princess Charlotte Bay, northeastern Australia (Crustacea: Ostracoda: Myodocopa: Cypridinidae)

ABSTRACT A new species of Paravargula is described from Princess Charlotte Bay, northeastern Australia. Members of the genus are widespread in the Indian and Pacific Oceans, but the genus was not previously known from Australia. The genus is divided into the HIRSUTA and ARBOREA Groups and a key is presented to the species in the latter group, which contains Paravargula karenae, new species.

Professor Andrew A. Benson: inspirational mentor

An active sea-going scientist, Professor Andrew A. Benson has an acclaimed reputation for innovative biochemistry, whether he is studying the path of carbon in photosynthesis, the lipid metabolism of biological membranes, the metabolism of arsenic in aquatic plants or calcitonin production in spawning salmon—to name only four of his thousand interests! He infects everyone whom he meets with his enthusiasm for scientific exploration, and the joys of discovery, whether his own or that of others. This engagement with others has allowed him to become a truly memorable mentor, particularly among the Australian science community, and he is treasured for it. Back in the early 1960s, after working with pioneers in radioactive carbon in the UC Berkeley’s Lawrence Radiation Laboratory to isolate the first products of carbon dioxide fixation in photosynthesis (Benson 2002)—truly brilliant achievements—Professor Benson moved to the Scripps Institution of Oceanography at La Jolla, California, where he became the founding chair of the Marine Biology Department, and later Director of the Physiological Research Laboratory and associate Director of the Institution. In keeping with his wide interests, the objective of his Marine Biology group was to understand the fundamental problems of biology and medicine, through a better understanding of marine organisms and the manner in which they adapt to life in the sea. Molecular, biochemical, physiological and ecological characteristics of marine plants, animals, and bacteria were all utilized in this search. This approach was stimulated by the aquisition of the research vessel RV Alpha Helix in 1966, a national facility, funded by the US National Science foundation, but managed by Scripps. Professors Benson and Scholander were intimately involved in the planning and devising of its scientific programmes. The facilities of this floating laboratory attracted many collaborating investigators from American and foreign institutions, and it was planned that the vessel would take groups of medical scientists and biologists to far corners of the marine world where they could learn from nature and each other. No longer scientists would be limited to the study of rats, mice and rabbits in their laboratories. They could find more specialized biological systems in the sea for understanding human disorders and problems (Benson 1992). The maiden voyage from Scripps to the Australian Great Barrier Reef in 1966 was no exception. This ‘‘Billabong’’ expedition had many objectives, including the study of reef symbioses between microscopic algae and reef building corals and Tridacna clams, salt and water regulation of mangroves, neurophysiologial studies of marine invertebrates, temperature regulation of reptiles, and physiological investigations of the ‘‘mermaid’’ sirenians—the gentle dugongs. I was to join Scripps cruise leader Professor Francis Haxo with a brief to identify the photosynthetic pigments of the phylogenetically unknown golden brown algae living symbiotically within reef animals, for which I had just developed a new micro-method. However, my first personal encounter with Professor Andy Benson was not on the Alpha Helix but on the remote air-field in far north Queensland adjacent to Princess Charlotte Bay (Fig. 1) when I was en route from Sydney to the ship to join her 1966 maiden voyage. Disembarking from the tiny twin-engined Cessna aircraft of the Bush Pilots Airways, I was greeted on the ‘‘air-field’’—a rough Queensland S. W. Jeffrey (&) CSIRO Division of Marine and Atmospheric Research, GPO Box 1538, Hobart, TAS 7001, Australia e-mail: shirley.jeffrey@csiro.au

Benthic diatom community composition in three regions of the Great Barrier Reef, Australia

Despite their ecological importance, very little is known about the taxonomy and ecology of benthic diatoms in coral-reef ecosystems. Diatom densities and community compositions were investigated in three distinct regions of the Great Barrier Reef (GBR): (a) Wet Tropics (WT), (b) Princess Charlotte Bay (PCB), and (c) the Outer Shelf (OS). About 209 taxa were observed in the GBR sediments studied, with an average abundance of 2.55 × 10^6 cells ml^−1 in the upper 1 cm of sediment. Total diatom abundances were about twice as high in inshore reefs of PCB and WT compared with OS reefs. A redundancy analysis (RDA) of diatom composition clearly grouped the three regions separately but showed little influence of grain size, nitrogen and organic carbon content of the sediments. The only distinct correlates were inorganic carbon and the distance to the mainland associated with OS communities. Analysis of similarity (ANOSIM) of diatom community composition revealed significant differences between all three regions. Indicator values showed that most highly abundant taxa occurred in all regions. However, several taxa were clearly identified as characteristic of particular regions. It is hypothesised that variations in nutrient and light availability are the most likely explanation for the observed differences in community composition.

Habitat and diet of the Star Finch (Neochmia ruficauda clarescens) in the early wet season at Princess Charlotte Bay, Cape York Peninsula, Australia

Surveys for the endangered Star Finch (Neochmia ruficauda clarescens (Hartert)) were conducted in the early wet season on Cape York Peninsula. We found Star Finches in only two grassland vegetation types. Most sightings were on unburnt islands of grass and saltbush on tidal saltpans where the birds were feeding solely on the seeds of the annual grass Xerochloa imberbis R.Br. Some individuals were also found among tall perennial grasses further inland where they fed on the first seed production of the new wet season. Xerochloa imberbis is probably a critical food source and saltpans a critical habitat for survival of this population of Star Finches during the early wet season.

The cycling and fate of terrestrially-derived sediments and nutrients in the coastal zone of the Great Barrier Reef shelf

The coastal zone of the Great Barrier Reef shelf, with an area of 30,000 km 2 and a water volume of 300 km 3, receives an average annual input of sediment on the order of 14–28 Mt y −1––an estimated two- to fourfold increase since European settlement. There is considerable concern about the impact and ultimate fate of terrestrially-derived nutrients entering the Great Barrier Reef World Heritage Area (GBRWHA). Analysis of current data suggests that microbial communities in coastal waters and in unconsolidated sediments metabolise nutrients equivalent to the entire dissolved and particulate nutrient load debouched from land. River-derived nutrients account for 40–80% of the carbon, 13–30% of the nitrogen, and 2–5% of the phosphorus necessary to support the observed rates of benthic and pelagic mineralisation in Princess Charlotte Bay in the far north, and in Rockingham Bay and Missionary Bay in the central section, of the GBRWHA. Nearly all nitrogen is ultimately returned to the atmosphere via denitrification. There is little net burial of nutrients in subtidal sediments. These budget estimates are based on a sparse data set, but it is clear that marine sources of nutrients (N-fixation by pelagic and benthic cyanobacteria) must be important, but the magnitude of these sources is poorly known and likely to be highly variable in space and time. Data from sediment trap deployments suggest that, despite significant re-suspension, sedimentation fluxes are sufficient to balance benthic mineralisation rates. Most organic material deposited to the benthos appears to be flocculent or colloidal aggregates, perhaps formed via microbial mediation and exudation of extra-cellular material. The geophysical dynamics of the coastal boundary layer plays an important role in concentrating biological and biogeochemical activity within a shallow, narrow coastal zone. Mangroves and tidal flats are small in area, but trap, transform, and store a disproportionate amount of sediment and organic matter within the GBRWHA. The highly efficient use of terrestrially-derived nutrients by benthic and pelagic microbes in the coastal zone helps to explain why coral reefs on the middle and outer shelf have remained relatively unscathed despite a significant increase in sediment delivery.

Catalogue of the Roth Collection of Aboriginal artefacts from north Queensland. Volume 4. Items collected from Nassau River, Night Island, Palmer River, Peak Point Electric Telegraph Office, Princess Charlotte Bay, Staaten River, Starcke River, Tinaroo, Tully River, Vanrook and Weipa (Embley River), in 1896–1903

Catalogue of the Roth Collection of Aboriginal artefacts from north Queensland. Volume 4. Items collected from Nassau River, Night Island, Palmer River, Peak Point Electric Telegraph Office, Princess Charlotte Bay, Staaten River, Starcke River, Tinaroo, Tully River, Vanrook and Weipa (Embley River),

Prehistoric and World War II Use of Shell Mounds in Darwin Harbour

Darwin Harbour is one of the largest bays along the Northern Territory coastline. Some shell mounds around the Harbour are renowned as the creations of the scrub-fowl Megapodius reinvardt (Stone 1989). However, the abundant archaeological middens that exist within the region have received little attention. While this failure to explore the archaeology of Darwin Harbour is being remedied in the regional study by Bums (1999), there is still a need for specific studies of site patteming within the region. In particular investigations of chronological and morphological variation in anthropogenic shell deposits and their environmental contexts will assist the evaluation of land-use models. Shell structures in Darwin Harbour exist within a geomorphic context underrepresented in studies of archaeological mounds in the Top End. Shell mounds studied elsewhere in northern Australia by archaeologists are generally on near-flat depositional surfaces produced by coastal progradation and composed entirely of alluvium or coastal sediments, and the interpretation of these sites is tied to the growth of coastal plains (eg. Bailey 1975 ; Baker 1981; Beaton 1985; Woodroffe et al. 1988). In contrast, Darwin Harbour consists of a flooded valley that has had relatively little sediment infilling, leaving a coastline that consists of bedrock and steep colluvial slopes that terminate below the high tide limit. Middens in Darwin Harbour, located on these steep rocky surfaces, are subject to different geomorphic conditions and reflect an environmental history different from mounds in regions such as Kakadu or Princess Charlotte Bay. Â In this paper we describe deposits of shell identified in one portion of Darwin Harbour, and document not only mound structures but also rings of shell. Our purpose is to provide an initial account of the diversity and chronology of these two kinds of archaeological shell deposits around Darwin Harbour and to discuss prehistoric settlement systems in that area of northern Australia. Our investigations focus on Haycock Reach, a small portion of the Harbour coastline which demonstrates a rich archaeological record. Â

Spatial analysis on a dugong consumption site at Princess Charlotte Bay, North Queensland

Spatial analysis on a dugong consumption site at Princess Charlotte Bay, North Queensland