Properties and faunal abundances of level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin

The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate (N=24-65 per station) 0.25 m**2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind/l (median 0.8 ind/l). In level ice, low ice algal pigment concentrations (<0.1-15.8 µg Chl a /l), low brine salinities (1.8-21.7) and flushing from the melting sea ice likely explain the low ice meiofauna concentrations. Higher abundances of Turbellaria, Nematoda and Harpacticoida also were observed in pressure ridges (0-200 ind/l, median 40 ind/l), although values were highly variable and only medians of Turbellaria were significantly higher in ridge ice than in level ice. Median abundances of under-ice amphipods at all ice types (level ice, various ice ridge structures) ranged from 8 to 114 ind/m**2 per station and mainly consisted of Apherusa glacialis (87%), Onisimus spp. (7%) and Gammarus wilkitzkii (6%). Highest amphipod abundances were observed in pressure ridges at depths >3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of enhanced summer ice melt. Previous estimates of Arctic sea ice meiofauna and under-ice amphipods on regional and pan-Arctic scales likely underestimate abundances at least in summer because they typically do not include pressure ridges.

Density and stable oxygen isotope profiles of four snow pits from Berkner Island, Filchner-Ronne Ice Shelf, Antarctica

The ice cap on Berkner Island is grounded on bedrock within the Filchner-Ronne Ice Shelf and is, therefore, expected to be a well-suited place to retrieve long-term ice-core records reflecting the environmental situation of the Weddell Sea region. Shallow firn cores were drilled to 11 m at the two main summits of Berkner Island and analysed in high depth resolution for electrical d.c. conductivity (ECM), stable isotopes, chloride, sulphate, nitrate and methane-sulphonate (MSA). From the annual layering of dD and non-sea-salt (nss) sulphate, a mean annual snow accumulation of 26.6 cm water at the north dome and 17.4 cm water at the south dome are obtained. As a result of ineffective wind scouring indicated by a relatively low near-surface snow density, regular annual cycles are found for all species at least in the upper 4-5 m. Post depositional changes are responsible for a substantial decrease of the seasonal dD and nitrate amplitude as well as for considerable migration of the MSA signal operating below a depth of 3-4 m. The mean chemical and isotopic firn properties at the south dome correspond to the situation on the Filchner-Ronne Ice shelf at a comparable distance to the coast, whereas the north dome is found to be more influenced by maritime air masses. Persistent high sea-salt levels in winter snow at Berkner Island heavily obscure the determination of nss sulphate probably due to sulphate fractionation in the Antartic sea-salt aerosols. Estimated time-scales predict ages at 400 m depth to be ca. 2000 years for the north and ca. 3000 years for the south dome. Pleistocene ice is expected in the bottom 200 and 300 m, respectively.

Physical and chemical analysis of firn cores from Ronne Ice Shelf, Antarctica

This data on the distribution of the accumulation rate and 18O content of near-surface layers in the eastern part of the Ronne Ice Shelf, Antarctica, were derived from an analysis of 16 firn cores. The firn cores were drilled along the traverse route of the Filchner-V-Campaign in 1995. The traverse followed an ice flowline of the Foundation Ice Stream and reached the margin of the inland ice, an area which has not yet been investigated. On the ice shelf the accumulation rates decrease with distance from the coast. Ascending to the inland ice the accumulation rates again reach almost coastal values. This regional distribution is in agreement with the temperature gradient along the traverse. The 18O content of the near-surface layers is closely related to the 10 m firn temperature. They strongly decrease from the grounding line towards the inland ice. At the southernmost site at 1100 m a.s.l., the mean d18O value of the firn decreases to -40?. Ice with that isotopic signature was found in cores from the central part of the Ronne Ice Shelf just above the marine ice layer, indicating that it originates from this area. All ice deposited as snow further south was melted beneath the ice shelf after passing the grounding-line area. The time series of accumulation rate and 18O content reveal no climatic trend during the last 30-50 years.

210Pb dates, radiocarbon ages and sedimentation and accumulation rates of sediment cores JM99-1198 and MD99-2297

The magnitude of Late Holocene climatic variations are less significant than those that took place during ice ages and deglaciations. However, detailed knowledge about this period is vital in order to understand and model future climate scenarios both as a result of natural climate variation and the effects of global warming. Oceanic heat flux is important for the sensitive climate regime of northern Europe. Our aim is to connect hydrographical changes, reflected by the dinoflagellates cyst (dinocysts) assemblages in the sediments in the Malangen fjord, to local and regional climatic phases. Previous studies have shown that dinocyst assemblages are influenced by temperature, salinity, and the availability of nutrients (e.g. de Vernal et al. 2005, doi:10.1016/j.quascirev.2004.06.014; de Vernal et al. 2001, doi:10.1002/jqs.659; Grosfjeld et al. this volume; Rochon et al. 2008, doi:10.1016/j.marmicro.2008.04.001; Solignac et al. this volume). Dinoflagellates are mostly unicellular organisms that make up one of the main groups of phytoplankton. They are able to regulate their depth within the photic zone and to concentrate along oceanic fronts, which provide nutrient-enriched waters. The dinoflagellate cysts are the hypnozygotes of dinoflagellates naturally produced during the life cycle. Their wall is composed of a highly resistant organic material, which has a high potential to fossilize. Because dinocysts species are linked to particular abiotic and biotic parameters, the dinocyst assemblages provide information about past surface water conditions. Since each fjord has its own hydrographic setting, it is necessary to establish a firm link between the dinocyst composition of the sediment surface samples and the surface water conditions. Indeed the modern dinocyst distribution in subarctic fjords is little known. Thus, in addition to detailing dinocyst results from two shallow cores, several sediment surface samples located along a transect running from the head to the mouth of the fjord, and extending onto the shelf, are also presented.

Radiocarbon ages, dose rates, water isotopic composition and hydrochemistry of samples from Komakuk Beach and Herschel Island

Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compare the late glacial and Holocene landscape development on both sides of the former ice margin based on permafrost sequences and ground ice. Analyses at these sites involved a multi-proxy approach including: sedimentology, cryostratigraphy, palaeoecology of ostracods, stable water isotopes in ground ice, hydrochemistry, and AMS radiocarbon and infrared stimulated luminescence (IRSL) dating. AMS and IRSL age determinations yielded full glacial ages at Komakuk Beach that is the northeastern limit of ice-free Beringia. Herschel Island to the east marks the Late Wisconsinan limit of the northwest Laurentide Ice Sheet and is composed of ice-thrust sediments containing plant detritus as young as 16.2 cal ka BP that might provide a maximum age on ice arrival. Late Wisconsinan ice wedges with sediment-rich fillings on Herschel Island are depleted in heavy oxygen isotopes (mean d18O of -29.1 per mil); this, together with low d-excess values, indicates colder-than-modern winter temperatures and probably reduced snow depths. Grain-size distribution and fossil ostracod assemblages indicate that deglaciation of the Herschel Island ice-thrust moraine was accompanied by alluvial, proluvial, and eolian sedimentation on the adjacent unglaciated Yukon Coastal Plain until ~11 cal ka BP during a period of low glacio-eustatic sea level. The late glacial-Holocene transition was marked by higher-than-modern summer temperatures leading to permafrost degradation that began no later than 11.2 cal ka BP and caused a regional thaw unconformity. Cryostructures and ice wedges were truncated while organic matter was incorporated and soluble ions were leached in the thaw zone. Thermokarst activity led to the formation of ice-wedge casts and deposition of thermokarst lake sediments. These were subsequently covered by rapidly accumulating peat during the early Holocene Thermal Maximum. A rising permafrost table, reduced peat accumulation, and extensive ice-wedge growth resulted from climate cooling starting in the middle Holocene until the late 20th century. The reconstruction of palaeolandscape dynamics on the Yukon Coastal Plain and the eastern Beringian edge contributes to unraveling the linkages between ice sheet, ocean, and permafrost that have existed since the Late Wisconsinan.

Sediment color variation in laminated Holocene sediments of ODP Site 178-1098

Continuous sediment color records with a resolution of one measurement per millimeter were generated for Site 1098 (Palmer Deep, Antarctic Peninsula) from digital images of the core surfaces to test if the laminated intervals at this site will allow for analysis of high-frequency climate variability in the Circum-Antarctic. Long-term variation in color values correlates with gamma-ray attenuation bulk density. Darker colors are found in laminated intervals with lower bulk density, high biogenic silica, and high total organic carbon content. Darker color values result from the addition of dark laminae to background sediments that show little variation in color. The thicknesses of dark and light laminae were measured in the top 25 meters composite depth to determine the temporal resolution of the laminae. The alternation between dark, biogenic-rich laminae and background sediment essentially represents an annual cycle, but the sediment is not consistently varved. The modal thickness of light laminae is close to the long-term average annual accumulation rate, and results indicate that approximately half of the dark/light couplets in distinctly laminated intervals represent a single year. Missing biogenic laminae are interpreted to represent reduced primary productivity during cold years with delayed breakup of the sea-ice cover.

Accumulation of organic carbon in the Laptev Sea

Composition and accumulation rates of organic carbon in Holocene sediments provided data to calculate an organic carbon budget for the Laptev Sea continental margin. Mean Holocene accumulation rates in the inner Laptev Sea vary between 0.14 and 2.7 g C cm**2/ky; maximum values occur close to the Lena River delta. Seawards, the mean accumulation rates decrease from 0.43 to 0.02 g C cm**2/ky. The organic matter is predominantly of terrigenous origin. About 0.9*10**6 t/year of organic carbon are buried in the Laptev Sea, and 0.25*10**6 t/year on the continental slope. Between about 8.5 and 9 ka, major changes in supply of terrigenous and marine organic carbon occur, related to changes in coastal erosion, Siberian river discharge, and/or Atlantic water inflow along the Eurasian continental margin.

Injuries leading to hospitalisation in the first year of life : analysis by trimester of age using coded data and textual description

Objective: To describe unintentional injuries to children aged less than one year, using coded and textual information, in three-month age bands to reflect their development over the year. Methods: Data from the Queensland Injury Surveillance Unit was used. The Unit collects demographic, clinical and circumstantial details about injured persons presenting to selected emergency departments across the State. Only injuries coded as unintentional in children admitted to hospital were included for this analysis. Results: After editing, 1,082 children remained for analysis, 24 with transport-related injuries. Falls were the most common injury, but becoming proportionately less over the year, whereas burns and scalds and foreign body injuries increased. The proportion of injuries due to contact with persons or objects varied little, but poisonings were relatively more common in the first and fourth three-month periods. Descriptions indicated that family members were somehow causally involved in 16% of injuries. Our findings are in qualitative agreement with comparable previous studies. Conclusion: The pattern of injuries varies over the first year of life and is clearly linked to the child's increasing mobility. Implications: Injury patterns in the first year of life should be reported over shorter intervals. Preventive measures for young children need to be designed with their rapidly changing developmental stage in mind, using a variety of strategies, one of which could be opportunistic developmentally specific education of parents. Injuries in young children are of abiding concern given their immediate health and emotional effects, and potential for long-term adverse sequelae. In Australia, in the financial year 2006/07, 2,869 children less than 12 months of age were admitted to hospital for an unintentional injury, a rate of 10.6 per 1,000, representing a considerable economic and social burden. Given that many of these injuries are preventable, this is particularly concerning. Most epidemiologic studies analyse data in five-year age bands, so children less than five years of age are examined as a group. This study includes only those children younger than one year of age to identify injury detail lost in analyses of the larger group, as we hypothesised that the injury pattern varied with the developmental stage of the child. The authors of several North American studies have commented that in dealing with injuries in pre-school children, broad age groupings are inadequate to do justice to the rapid developmental changes in infancy and early childhood, and have in consequence analysed injuries in shorter intervals. To our knowledge, no similar analysis of Australian infant injuries has been published to date. This paper describes injury in children less than 12 months of age using data from the Queensland Injury Surveillance Unit (QISU).

Random breath testing in Queensland and Western Australia : Examination of how the random breath testing rate influences alcohol related traffic crash rates

In this paper we explore the relationship between monthly random breath testing (RBT) rates (per 1000 licensed drivers) and alcohol-related traffic crash (ARTC) rates over time, across two Australian states: Queensland and Western Australia. We analyse the RBT, ARTC and licensed driver rates across 12 years; however, due to administrative restrictions, we model ARTC rates against RBT rates for the period July 2004 to June 2009. The Queensland data reveals that the monthly ARTC rate is almost flat over the five year period. Based on the results of the analysis, an average of 5.5 ARTCs per 100,000 licensed drivers are observed across the study period. For the same period, the monthly rate of RBTs per 1000 licensed drivers is observed to be decreasing across the study with the results of the analysis revealing no significant variations in the data. The comparison between Western Australia and Queensland shows that Queensland's ARTC monthly percent change (MPC) is 0.014 compared to the MPC of 0.47 for Western Australia. While Queensland maintains a relatively flat ARTC rate, the ARTC rate in Western Australia is increasing. Our analysis reveals an inverse relationship between ARTC RBT rates, that for every 10% increase in the percentage of RBTs to licensed driver there is a 0.15 decrease in the rate of ARTCs per 100,000 licenced drivers. Moreover, in Western Australia, if the 2011 ratio of 1:2 (RBTs to annual number of licensed drivers) were to double to a ratio of 1:1, we estimate the number of monthly ARTCs would reduce by approximately 15. Based on these findings we believe that as the number of RBTs conducted increases the number of drivers willing to risk being detected for drinking driving decreases, because the perceived risk of being detected is considered greater. This is turn results in the number of ARTCs diminishing. The results of this study provide an important evidence base for policy decisions for RBT operations.

Acute injuries in track and field athletes: A 3-year observational study at the Penn Relays Carnival with epidemiology and medical coverage implications

Background Few studies have examined acute injuries in track and field in both elite and sub-elite athletes. Purpose To observe the absolute and relative rates of injury in track and field athletes across a wide range of competition levels and ages during three years of the Penn Relays Carnival to assist with future medical coverage planning and injury prevention strategies. Study design: Descriptive epidemiology study. Methods Over a 3-year period all injuries treated by the medical staff were recorded on a standardised injury report form. Absolute injury rates (absolute number of injuries) and relative injury rates (number of injuries per 1000 participants) were determined and odds ratios (OR) of injury rates were calculated between sexes, competition levels and events. Injuries were also broken down into major or minor medical or orthopedic injuries. Results Throughout the study period 48,473 competing athletes participated in the Penn Relays Carnival, and 436 injuries were sustained. For medical coverage purposes, the relative rate of injury subtypes was greatest for minor orthopedic injuries (5.71 injuries per 1000 participants), followed by minor medical injuries (3.42 injuries per 1000 participants), major medical injuries (0.69 injuries per 1000 participants) and major orthopedic injuries (0.18 injuries per 1000 participants). College/elite level athletes displayed the lowest relative injury rate (7.99 injuries per 1000 participants), which was significantly less than high school (9.87 injuries per 1000 participants) and masters level athletes (16.33 injuries per 1000 participants). Males displayed a greater likelihood of suffering a minor orthopedic injury compared to females (OR = 1.36, 95% CI = 1.06 to 1.75; χ2 = 5.73, p = 0.017) but were less likely to sustain a major medical injury (OR = 0.33, 95% CI = 0.15 to 0.75; χ2 = 7.75, p = 0.005). Of the three most heavily participated in events, the 4 x 400m relay displayed the greatest relative injury rate (13.6 injuries per 1000 participants) compared to the 4 x 100 and 4 x 200m relay. Conclusions Medical coverage teams for future large scale track and field events need to plan for at least two major orthopedic and seven major medical injuries per 1000 participants. Male track and field athletes, particularly masters level male athletes, are at greater risk of injury compared to other genders and competition levels.

Risedronate in adults with osteogenesis imperfecta type I: Increased bone mineral density and decreased bone turnover, but high fracture rate persists

Summary Bisphosphonates can increase bone mineral density (BMD) in children with osteogenesis imperfecta (OI). In this study of adults with OI type I, risedronate increased BMD at lumbar spine (but not total hip) and decreased bone turnover. However, the fracture rate in these patients remained high. Introduction Intravenous bisphosphonates given to children with OI can increase BMD and reduce fracture incidence. Oral and/or intravenous bisphosphonates may have similar effects in adults with OI. We completed an observational study of the effect of risedronate in adults with OI type I. Methods Thirty-two adults (mean age, 39 years) with OI type I were treated with risedronate (total dose, 35 mg weekly) for 24 months. Primary outcome measures were BMD changes at lumbar spine (LS) and total hip (TH). Secondary outcome measures were fracture incidence, bone pain, and change in bone turnover markers (serum procollagen type I aminopropeptide (P1NP) and bone ALP). A meta-analysis of published studies of oral bisphosphonates in adults and children with OI was performed. Results Twenty-seven participants (ten males and seventeen females) completed the study. BMD increased at LS by 3.9% (0.815 vs. 0.846 g/cm 2, p=0.007; mean Z-score, -1.93 vs. -1.58, p=0.002), with no significant change at TH. P1NP fell by 37% (p=0.00041), with no significant change in bone ALP (p=0.15). Bone pain did not change significantly (p=0.6). Fracture incidence remained high, with 25 clinical fractures and 10 major fractures in fourteen participants (0.18 major fractures per person per year), with historical data of 0.12 fractures per person per year. The meta-analysis did not demonstrate a significant difference in fracture incidence in patients with OI treated with oral bisphosphonates. Conclusions Risedronate in adults with OI type I results in modest but significant increases in BMD at LS, and decreased bone turnover. However, this may be insufficient to make a clinically significant difference to fracture incidence.

Where to from Brahmans in the Northern Australian herd? Maintaining the economic benefit of earlier infusions of Bos indicus.

The economic performance of a terminal crossbreeding system based on Brahman cows and a tropically adapted composite herd were compared to a straightbred Brahman herd. All systems were targeted to meet specifications of the grass-finished Japanese market. The production system modelled represented a typical individual central Queensland integrated breeding/finishing enterprise or a northern Australian vertically integrated enterprise with separate breeding and finishing properties. Due mainly to a reduced age of turnoff of Crossbred and Composite sale animals and an improved weaning rate in the Composite herd, Crossbred and Composite herds returned a gross margin of $7 and $24 per Adult Equivalent (AE) respectively above that of the Brahman herd. The benefits of changing 25% of the existing 85% of Brahmans in the northern Australian herd to either Crossbreds or Composites over a 10-year period were also examined. With no premium for carcass quality in Crossbred and Composite sale animals, annual benefits were $16 M and $61 M for Crossbreds and Composites in 2013. The cumulative Present Value (PV) of this shift over the 10-year period was $88 M and $342 M respectively, discounted at 7%. When a 5c per kg premium for carcass quality was included, differences in annual benefits rose to $30 M and $75 M and cumulative PVs to $168 M and $421 M for Crossbreds and Composites respectively.