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It has been proposed that the ventilation of the deep Pacific carbon pool was not significantly reduced during the last glacial period, posing a problem for canonical theories of glacial-interglacial CO2 change. However, using radiocarbon dates of marine

Bones from extinct Australian marsupials found at Spring Creek, Victoria, and in the Mowbray Swamp, Tasmania, have yielded scattered and anomalously young radiocarbon ages measured on collagen, gelatin or ultrafiltered gelatin. We resampled previously dated material from those two sites and from Mt Cripps, Tasmania, as well as a control sample from Zaglik, Russia, to compare chronologies based on XAD-2 purified total amino acid fractions and collagen purified by ultrafiltration (UF) or less rigorous methods. Our age from the control site bone gave a similar infinite age, while six out of seven other comparisons yielded radiocarbon ages on total amino acid fractions older than those previously measured on collagen or gelatin. The Palorchestes from Spring Creek yielded a date of >53500 BP.

We describe new radiocarbon-dated evidence for the late survival of beavers from an upland site in northern England. A wood specimen with beaver gnaw marks was recovered from the bank of the Scaup Burn in Kielder Forest in Northumberland. The marks were analysed, the tree species were identified and the sample was radiocarbon dated to between 1269 and 1396. Other wood remains in the same context suggest a most likely dating between 1330 and 1390. This find represents the most recent radiocarbon-dated physical evidence of beaver yet found in Britain, by at least 400 years. In conjunction with documentary and other archaeological evidence from the period, this discovery indicates beaver were present within the Tyne River catchment up until at least the 14th century ad. In addition, this find highlights the need to investigate all possible evidence of beaver fully when discovered and to remain open-minded about the possibility of making finds in unexpected locations and contexts.

Recent theories for glacial-interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a "bipolar ventilation seesaw." However, the viability of this hypothesis has been contested

Since the late 1980s, northern Iberia has yielded some of the earliest radiocarbon dated Aurignacian assemblages in Western Europe, probably produced by anatomically modern humans (AMHs). This is at odds with its location furthest from the likely eastern

Marine reservoir ages are a key element in calculating and constraining uncertainty in radiocarbon age estimates and are also essential to better understand regional ocean circulation. In this study, we present a new method to reconstruct long-term, high-resolution sea surface reservoir ages based on analysis of the organic skeleton of deep-sea (560. m) black coral (Anthozoa, Antipatharia). Our results confirm that antipatharians are extremely slow growing (typical radial growth rate for a South Pacific specimen around 0.03. mm/yr). Coupled uranium series and radiocarbon measurements were made on black coral collected live from the Norfolk Ridge (north Tasman Sea) to provide the first modern reservoir ages for this region. At the Norfolk Ridge, the average reservoir age between 1790 AD and 1900. AD was ~330 years. This was followed by a steep decrease over time of about 70 years to 1950 AD (our most modern value). This indicates an increase in surface ocean ventilation of water masses in this region. These results are consistent with observational studies for the early twentieth century, which suggest significant changes in regional circulation of the southwest pacific.

Little is known about growth rates of deep-water reef-forming corals or the rates at which these reefs accumulate. Such information is critical for determining the resilience of the reefs to anthropogenic impacts such as trawling and climate change. We radiocarbon date live-caught and sub-fossil samples of the bioherm-forming coral Solenosmilia variabilis collected from precisely known depths and locations by means of a remotely operated vehicle on seamounts south of Tasmania, Australia. The growth rate of colonies live-caught between 958 and 1,454 m, which spans most of the depth range of the species locally, ranged from 0.84 to 1.25 mm linear extension yr-1 and tended to be higher in the deeper-caught material. Analysis of skeletal microstructure suggests annual deposition of growth increments near the growing tips, but not closer to the base, as the skeleton is extended and thickened. Dating of sub-fossil material indicates S. variabilis has been present on Tasmanian seamounts for at least the last 47,000 yrs and a reef accumulation rate of 0.27 mm yr-1.

Two-component models are often used to determine the contributions made by fossil fuel and natural sources of carbon in airborne particulate matter (PM). The models reduce thousands of actual sources to two end members based on isotopic signature. Combustion of fossil fuels produces PM free of carbon-14 (14C). Wood or charcoal smoke, restaurant fryer emissions, and natural emissions from plants produce PM with the contemporary concentration of 14C approximately 1.2 × 10-1214C/C. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading and radiocarbon analysis is becoming a popular source apportionment method. Emissions from incinerators combusting medical or biological wastes containing tracer 14C can skew the 14C/C ratio of PM, however, so critical analysis of sampling sites for possible sources of elevated PM needs to be completed prior to embarking on sampling campaigns. Results are presented for two ambient monitoring sites in different areas of the United States where 14C contamination is apparent. Our experience suggests that such contamination is uncommon but is also not rare (∼10%) for PM sampling sites.

This paper presents 29 radiocarbon dates from eight surface concentrations of shell and 10 test-pits across four shell middens at Long Point in the Coorong, South Australia. Results indicate that occupation of these sites was confined to the late Holocene

Past glacial-interglacial climate transitions were accompanied by millennial-scale pulses in atmospheric CO2 that are widely thought to have resulted from the release of CO2 via the Southern Ocean. However, direct proxy evidence for a Southern Ocean role

We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Mountains, Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally harvested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a high- land burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is concurrent with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom ritual relative to known funerary rituals of the pre to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia.

Assigning accurate dates to hypersaline sediments opens important terrestrial records of local and regional paleoecologies and paleoclimatology. However, as of yet no conventional method of dating hypersaline systems has been widely adopted. Biomarker, mineralogical, and radiocarbon analyses of sediments and organic extracts from a shallow (13. cm) core from a hypersaline playa, Lake Tyrrell, southeastern Australia, produce a coherent age-depth curve beginning with modern microbial mats and extending to ~. 7500. cal. yr. BP. These analyses are furthermore used to identify and constrain the timing of the most recent change in hydrological regime at Lake Tyrrell, a shift from a clay deposit to the precipitation of evaporitic sands occurring at some time between ~. 4500 and 7000. yr. These analyses show the potential for widespread dating of hypersaline systems integrating the biomarker approach, reinforce the value of the radiocarbon content of biomarkers in understanding the flow of carbon in modern ecologies, and validate the temporal dimension of data provided by biomarkers when dating late Quaternary sediments.

We report the first uranium-series age estimates for rock art in China. Calcite bracketing a paint layer was used to constrain the age of a naturalistic outline hunter-gatherer painting in the Jinsha River area of northwest Yunnan Province (southwest China). The rock paintings in this region are unique in style and content compared with other bodies of rock art in China, which are dominated by Neolithic subject matter. The minimum and maximum ages were determined using isochron techniques on multiple samples of calcite from above and beneath the paint layer. A large painted deer head was dated to between 5738 and 2050 years. This painting and underlying flowstone are superimposed on older paintings that suggest the older paintings are at least 3400 years old, if not older than 5738 years. The results indicate for the first time that Jinsha River rock art is older than other forms of rock art in the region and show that rock art likely extends back to at least the transition from the Palaeolithic to Neolithic in this part of China.

This paper presents the initial radiocarbon ages from the Lower Murray Archaeological Project developed in conjunction with the Ngarrindjeri Heritage Committee in South Australia. As part of this community based research program, a total of 59 shell (V. ambiguus) and charcoal samples were selected for radiocarbon dating. Radiocarbon ages varied significantly between sites within the region and ranged from 150-490 calBP at Pomberuk (Hume Reserve Midden and Historic Campsite) to 8190-8390 calBP at Glen Lossie Midden and Burial Site (GLMBS). These results will contribute to developing a more comprehensive understanding of human occupation in Ngarrindjeri ruwe (lands and waters) and assist in developing a local chronology for the region.

We report the first uranium-series age estimates for rock art in China. Calcite bracketing a paint layer was used to constrain the age of a naturalistic outline hunter-gatherer painting in the Jinsha River area of northwest Yunnan Province (southwest China). The rock paintings in this region are unique in style and content compared with other bodies of rock art in China, which are dominated by Neolithic subject matter. The minimum and maximum ages were determined using isochron techniques on multiple samples of calcite from above and beneath the paint layer. A large painted deer head was dated to between 5738 and 2050 years. This painting and underlying flowstone are superimposed on older paintings that suggest the older paintings are at least 3400 years old, if not older than 5738 years. The results indicate for the first time that Jinsha River rock art is older than other forms of rock art in the region and show that rock art likely extends back to at least the transition from the Palaeolithic to Neolithic in this part of China.

We describe a previously unknown assemblage of seamount-associated megabenthos that has by far the highest peak biomass reported in the deep-sea outside of vent communities. The assemblage was found at depths of 2-2.5 km on rocky geomorphic features off the southeast coast of Australia, in an area near the Sub-Antarctic Zone characterised by high rates of surface productivity and carbon export to the deep-ocean. These conditions, and the taxa in the assemblage, are widely distributed around the Southern mid-latitudes, suggesting the high-biomass assemblage is also likely to be widespread. The role of this assemblage in regional ecosystem and carbon dynamics and its sensitivities to anthropogenic impacts are unknown. The discovery highlights the lack of information on deep-sea biota worldwide and the potential for unanticipated impacts of deep-sea exploitation.

Ocean acidification has been predicted to reduce the ability of marine organisms to produce carbonate skeletons, threatening their long-term viability and severely impacting marine ecosystems. Corals, as ecosystem engineers, have been identified as particularly vulnerable and important. To determine the sensitivity of corals and allied taxa to long-term exposure to very low carbonate concentrations, we examined the distribution and skeletal characteristics of coral taxa along a natural deep-sea concentration gradient on seamounts of SW Australia. Carbonate undersaturation had little evident effect on the depth distribution, growth or skeletal composition of live scleractinians or gorgonians, with corals growing, often abundantly, in waters as much as 20 to 30% under-saturated. Developmental anomalies in the deepest skeleton-forming anthozoan collected (an isidid gorgonian, at nearly 4 km depth) suggest an absolute low tolerance limit of about 40% under-saturation. Evidence for an effect of acidification on the accumulation of reef structure is ambiguous, with clear indications of dissolution of high-magnesium calcite (HMC) gorgonian skeletons at depths below 2300 m, but also abundant, old scleractinian skeletons well below the aragonite saturation horizon. The latter might be the result of ferromanganese deposition on exposed skeletons, which, however, may render them inhospitable for benthic organisms.

The mineral waste from some mines has the capacity to trap and store CO2 within secondary carbonate minerals via the process of silicate weathering. Nesquehonite [MgCO3•3H2O] forms by weathering of Mg-silicate minerals in kimberlitic mine tailings at th

Bamboo corals (Order Gorgonacea, Family Isididae) are attractive prospects for deep-sea paleoceanographic reconstruction, capturing trace elements in their calcitic skeletons that may serve as environmental proxies with subdecadal resolution over multi-century timescales. We study the reproducibility and fidelity of trace-element profiles (Ba, Mg, Sr, Mn, U, Pb) in a 420-year-old specimen of the bamboo coral . Keratoisis sp. from the SE USA.Using laser-ablation ICP-MS to obtain multiple replicate profiles, we use spectral techniques to distinguish noise and irreproducible variations from fully reproducible geochemical fluctuations that are candidates for environmental signals. By quantifying variability between profiles, we assess the fidelity with which the corals potentially record environmental information.Barium is the most reproducible element in the skeleton, with large fluctuations along different growth radii reproducing to within 4%. Both Mg and Sr have very uniform levels within the coral, but display low-amplitude irreproducible variations that might represent an internal biological process. In the case of Mg, which has been proposed as a paleotemperature proxy, this irreproducibility would represent an intrinsic uncertainty of ~±0.1 to 0.4. °C. Both Mn and Pb contain some irreproducibility superimposed upon broad reproducible profiles that may be environmental signals. Some of the irreproducible Pb fluctuations correlate with cracks and dark bands in the sample suggesting detrital or surface contamination. Uranium displays large amplitude variations which are not reproducible along different radii. This suggests that uranium cannot be used for paleoenvironmental reconstruction, and may show signs of early diagenesis - a possibility that could complicate attempts to date young . Keratoisis sp. samples by U-series geochemistry.The highly reproducible Ba signal allows precise alignment of profiles and thus we can show that growth rate along one radius can v

A previous assessment of radiocarbon (14C) dates from alluvial units in southeastern Australia revealed a gap in the geochronological record that coincides with the Holocene climatic optimum. This gap in the alluvial record can be further refined using optically stimulated luminescence (OSL). The chronology of Holocene river terraces on Widden Brook, a sandy alluvial stream in southeastern Australia, was established using 14C and OSL techniques. Combined use of these independent techniques allows for a more rigorous assessment of the alluvial record. The robust chronology, consisting of 38 14C and 11 OSL samples, permitted identification of significant depositional variation within the catchment, resulting from localised geomorphic processes. The three terrace sequences identified yielded distinct chronologies, suggesting alluvial deposition at different times. The sequences exhibited a continuous chronology, which indicated continuous deposition throughout the Holocene. The chronology of terrace sequences within this catchment suggests that terrace formation can be attributed to localised geomorphic processes rather than climatic forcing.

Past glacial-interglacial increases in the concentration of atmospheric carbon dioxide (CO2) are thought to arise from the rapid release of CO2 sequestered in the deep sea, primarily via the Southern Ocean. Here, we present radiocarbon evidence from the Atlantic sector of the Southern Ocean that strongly supports this hypothesis. We show that during the last glacial period, deep water circulating around Antarctica was more than two times older than today relative to the atmosphere. During deglaciation, the dissipation of this old and presumably CO2-enriched deep water played an important role in the pulsed rise of atmospheric CO2 through its variable influence on the upwelling branch of the Antarctic overturning circulation.

In February 2007, a single stage AMS from the National Electrostatics Corporation (NEC) was installed at the Research School of Earth Sciences at the Australian National University. This instrument is equipped with a gas/graphite hybrid ion source allowing direct analysis of CO2 as well as traditional graphite targets. The instrument was funded by an Australian Research Council grant and by a consortium of eight universities plus the CSIRO Division of Land and Water. Its purpose is to support integrated environmental and archaeological research and access is open to the wider research community. In the first year ∼1500 samples have been analysed. A precision of ∼3‰ is routinely observed. The background for processed graphite (coal, calcite, Carrera marble) is better than 45,000 years. This paper summarizes the first year of measurements.

In 2008, we began two related research projects that focus on recent Australian rock art, made after the arrival of Asians and Europeans, in part of northwest Arnhem Land's Wellington Range. This area has extensive and diverse rock art, including many examples of paintings that reflect contact between local Aboriginal people and visitors to their shores. At some sites figures made of beeswax are found superimposed under and over paintings, thus providing a means of obtaining minimum and maximum ages for pigment art. We report on the results of an initial radiocarbon beeswax dating programme at the Djulirri site complex. Results include the earliest age for a depiction of a Southeast Asian watercraft in Australian rock art, which is also Australia's earliest contact period rock art depiction discovered so far. Based on the probability distribution of the calibrated ages, it is 99.7% probable this image dates to before AD 1664 and likely is much older. The significance of this result is discussed in relation to early contact history, as revealed by historic documents and archaeological excavation. Other important results suggest a close encounter between local Aboriginal people and Europeans occurred in the 1700s, before British exploration and settlement in the Arnhem Land region.

Research into the palaeoenvironmental history of New Caledonia was begun independently by Hope and Stevenson in the early 1990s. While the original work of Hope and colleagues was centred around questions of the long-term vegetation dynamics of maquis and rainforest within the ultramafic terrain of New Caledonia (Hope and Pask 1998; Read et al. 2000), Stevenson and colleagues were exploring questions of human impact and the detection of initial human settlement (Stevenson and Dodson 1995; Stevenson 1998; Stevenson et al. 2001; Stevenson 2004). Hope and Stevenson later came together to work on the longest record so far recovered from the tropical southwest Pacific, Lake Xere Wapo in southwest New Caledonia. Having published the initial findings from this site (Stevenson and Hope 2005), a major problem remained, that of a robust chronology. The 12 m core XW-B reached radiocarbon background shortly after 300 cm, had several significant age inversions and had what appeared to be a very shallow Holocene sequence of fewer than 20 cm. Stevenson and Hope revisited Lake Xere Wapo in 2005, collecting new material for further dating aimed at untangling the chronology. Results from this new dating program are reported here, with a summary of previous radiocarbon determinations.

We present a novel application for radiocarbon dating by aging 4 scales from a single large adult lungfish (Neoceratodus forsteri) from the Burnett River, in Queensland, Australia. The relict fish species lack a solid crystalline otolith, which precludes the use of the otolith annuli as a reliable age indicator. Previous attempts to age lungfish using a number of techniques have had only limited success. We report on ages obtained from the dense lamellar bone of the scale, which were isolated from the organic layers that thicken and subsequently obscure the 14C signal. Using the characteristics of the bomb curve, 2 parameter von Bertanalffy growth functions were fit, providing an estimate of absolute age to be ∼65–70 yr. The information gleaned from this study will aid in assessing the population structure, and therefore management, of this vulnerable species.

The ability to reliably age siliceous sponges is explored using radiocarbon dating of several hexactinellid sponge specimens including Rossella racovitzae racovitzae Topsent, 1901 (C. Hexactinellida: O. Lyssacinosida: F. Rossellidae), collected from the Ross Sea, Antarctica. The optimal pretreatment was found to consist of both sequential acid digestion and pre-roasting at temperatures >400 °C. Subsequent combustion at 900 °C liberated the proteinaceous material within the spicule matrix and once the reservoir age of the surrounding water was accounted for, a linear extension rate was calculated to be around 2.9 mm yr-1, aging the sponge at ∼440 years old.

The marine cyanobacterium Trichodesmium is ubiquitous in tropical and subtropical seas and is an important contributor to global N and C cycling. We sought to characterize metabolic uptake patterns in individual Trichodesmium IMS-101 cells by quantitatively imaging13C and15N uptake with high-resolution secondary ion mass spectrometry (NanoSIMS). Trichodesmium fix both CO2 and N2 concurrently during the day and are, thus, faced with a balancing act: the O2 evolved during photosynthesis inhibits nitrogenase, the key enzyme in N2 fixation. After performing correlated transmission electron microscopy (TEM) and NanoSIMS analysis on trichome thin-sections, we observed transient inclusion of15N and13C into discrete subcellular bodies identified as cyanophycin granules. We speculate that Trichodesmium uses these dynamic storage bodies to uncouple CO2 and N2 fixation from overall growth dynamics. We also directly quantified both CO2 and N2 fixation at the single cell level using NanoSIMS imaging of whole cells in multiple trichomes. Our results indicate maximal CO2 fixation rates in the morning, compared with maximal N2 fixation rates in the afternoon, bolstering the argument that segregation of CO2 and N2 fixation in Trichodesmium is regulated in part by temporal factors. Spatial separation of N2 and CO2 fixation may also have a role in metabolic segregation in Trichodesmium. Our approach in combining stable isotope labeling with NanoSIMS and TEM imaging can be extended to other physiologically relevant elements and processes in other important microbial systems.

Bamboo corals (Family Isididae) are an important component of seamount benthos south of Tasmania. Besides having lifespans of up to 400 yr, little is known about their basic ecology, nor how to decode potential climate signals encoded in their skeletons.

Fine particulate matter collected at two urban, four near-urban, and six remote sites throughout the United States were analyzed for total carbon (TC) and radiocarbon (14C). Samples were collected at most sites for both a summer and winter season. The radiocarbon was used to partition the TC into fossil and contemporary fractions. On average, contemporary carbon composed about half of the carbon at the urban, ∼70-97% at near-urban, and 82-100% at remote sites. At Phoenix, Arizona, and Seattle, Washington, one monitor was located within the urban center and one outside to assess the urban excess over background concentrations. During the summer the urban and rural sites had similar contemporary carbon concentrations. However, during the winter the urban sites had more than twice the contemporary carbon measured at the neighboring sites, indicating anthropogenic contributions to the contemporary carbon. The urban fossil carbon was 4-20 times larger than the neighboring rural sites for both seasons. Organic (OC) and elemental carbon (EC) from TOR analysis were available. These and the radiocarbon data were used to estimate characteristic fossil and contemporary EC/TC ratios for the winter and summer seasons. These ratios were applied to carbon data from the Interagency Monitoring of Protected Visual Environments network to estimate the fraction of contemporary carbon at mostly rural sites throughout the United States. In addition, the ratios were used to develop a semiquantitative, lower bound estimate of secondary organic carbon (SOC) contribution to fossil and contemporary carbon. SOC accounted for more than one-third of the fossil and contemporary carbon.

Particulate matter aerosols contribute to haze diminishing vistas and scenery at national parks and wilderness areas within the United States. To increase understanding of the sources of carbonaceous aerosols at these settings, the total carbon loading and 14C/C ratio of PM 2.5 aerosols at nine Interagency Monitoring for Protection of Visual Environments (IMPROVE) network sites were measured. Aerosols were collected weekly in the summer and winter at one rural site, two urban sites, five sites located in national parks and one site located in a wildlife preserve. The carbon measurements together with the absence of 14C in fossil carbon materials and known 14C/C levels in contemporary carbon materials were used to derive contemporary and fossil carbon contents of the particulate matter. Contemporary and fossil carbon aerosol loadings varied across the sites and suggest different percentages of carbon source inputs. The urban sites had the highest fossil carbon loadings that comprised around 50% of the total carbon aerosol loading. The wildlife preserve and national park sites together with the rural site had much lower fossil carbon loading components. At these sites, variations in the total carbon aerosol loading were dominated by nonfossil carbon sources. This suggests that reduction of anthropogenic sources of fossil carbon aerosols may result only in little decrease in carbonaceous aerosol loading at many national parks and rural areas. Examination of the major sources of uncertainty that might cause contemporary carbon contents to be artificially high indicates that potential errors and biases in the methodology do not change the fundamental conclusions of this study.

Filamentous nitrogen fixing cyanobacteria are key players in global nutrient cycling, but the relationship between CO"2- and N"2-fixation and intercellular exchange of these elements remains poorly understood in many genera. Using high-resolution nanometer-scale secondary ion mass spectrometry (NanoSIMS) in conjunction with enriched H13CO"3- and 15N"2 incubations of Anabaena oscillarioides, we imaged the cellular distributions of C, N and P and 13C and 15N enrichments at multiple time points during a diurnal cycle as proxies for C and N assimilation. The temporal and spatial distributions of the newly fixed C and N were highly heterogeneous at both the intra- and inter-cellular scale, and indicative of regions performing active assimilation and biosynthesis. Subcellular components such as the neck region of heterocycts, cell division septae and putative cyanophycin granules were clearly identifiable by their elemental composition. Newly fixed nitrogen was rapidly exported from heterocysts and was evenly allocated among vegetative cells, with the exception of the most remote vegetative cells between heterocysts, which were N limited based on lower 15N enrichment. Preexisting functional heterocysts had the lowest levels of 13C and 15N enrichment, while heterocysts that were inferred to have differentiated during the experiment had higher levels of enrichment. This innovative approach, combining stable isotope labeling and NanoSIMS elemental and isotopic imaging, allows characterization of cellular development (division, heterocyst differentiation), changes in individual cell composition and cellular roles in metabolite exchange.

We use a combination of nanometer-resolution secondary ion mass spectrometry (NanoSIMS) and analytical transmission electron microscopy (ATEM) for chemical imaging of material transformed in a laser-heated diamond anvil cell (LH-DAC), in the pressure and

The Center for AMS, Lawrence Livermore National Laboratory (CAMS) modified high-intensity Cs+ sputter source has several key characteristics, including very high ion current output, that make it useful for AMS applications. Within the AMS community there

Coralline sponges (sclerosponges) have been proposed as a new source for paleo subsurface temperature reconstructions by utilizing methods developed for reef-building corals. However unlike corals, they do not have density variations, making age determination difficult. In this study, we examined multiple elemental ratios (B / Ca, Mg / Ca, Sr / Ca, Ba / Ca, U / Ca) in the coralline sponge Astrosclera willeyana. We also measured skeletal density profiles along the outer "living" edge of the sponges and these data indicate significant thickening of skeletal material over intervals of 2-3 mm which corresponds to 2-3 years. This suggests that any skeletal recovered environmental record from A. willeyana is an integration of signals over a ∼2-3 year period. Sponge Sr / Ca seemed to hold the most promise as a recorder of water temperature and we compared Sr / Ca from 2 sponges in the Great Barrier Reef and one from Truk in Micronesia to their respective sea surface temperature record. The correlations were not strong (∼r = - 0.5) but were significant. It appears that the signal smoothing due to thickening or perhaps even some other control (biologic, biomineralization) on Sr skeletal partitioning limits the use of Sr / Ca as an indicator of water temperature in A. willeyana. Variations of B / Ca, Mg / Ca, Ba / Ca and U / Ca only have moderate to poor correlations to Sr / Ca and are not consistent between samples. They also do not show correlations with water temperature and may be more heavily influenced by the biomineralization occurring in the secondary thickening.