Palaeoenvironment records of six sediment cores collected in the Gulf of Carpentaria

The Gulf of Carpentaria is an epicontinental sea (maximum depth 70 m) between Australia and New Guinea, bordered to the east by Torres Strait (currently 12 m deep) and to the west by the Arafura Sill (53 m below present sea level). Throughout the Quaternary, during times of low sea-level, the Gulf was separated from the open waters of the Indian and Pacific Oceans, forming Lake Carpentaria, an isolation basin, perched above contemporaneous sea-level with outlet channels to the Arafura Sea. A preliminary interpretation is presented of the palaeoenvironments recorded in six sediment cores collected by the IMAGES program in the Gulf of Carpentaria. The longest core (approx. 15 m) spans the past 130 ka and includes a record of sea-level/lake-level changes, with particular complexity between 80 and 40 ka when sea-level repeatedly breached and withdrew from Gulf/Lake Carpentaria. Evidence from biotic remains (foraminifers, ostracods, pollen), sedimentology and geochemistry clearly identifies a final marine transgression at about 9.7 ka (radiocarbon years). Before this transgression, Lake Carpentaria was surrounded by grassland, was near full, and may have had a surface area approaching 600 km-300 km and a depth of about 15 m. The earlier rise in sea-level which accompanied the Marine Isotopic Stage 6/5 transgression at about 130 ka is constrained by sedimentological and biotic evidence and dated by optical- and thermoluminescence and amino acid racemisation methods.

Radiocarbon dating, oxygen isotopes, and sea-level reconstruction of sediment core GeoB5844-2 from the northern end of the Red Sea

Based on a radiocarbon and paleomagnetically dated sediment record from the northern Red Sea and the exceptional sensitivity of the regional changes in the oxygen isotope composition of sea water to the sea-level-dependent water exchange with the Indian Ocean, we provide a new global sea-level reconstruction spanning the last glacial period. The sea-level record has been extracted from the temperature-corrected benthic stable oxygen isotopes using coral-based sea-level data as constraints for the sea-level/oxygen isotope relationship. Although, the general features of this millennial-scale sea-level records have strong similarities to the rather symmetric and gradual Southern Hemisphere climate patterns, we observe, in constrast to previous findings, pronounced sea level rises of up to 25 m to generally correspond with Northern Hemisphere warmings as recorded in Greenland ice-core interstadial intervals whereas sea-level lowstands mostly occur during cold phases. Corroborated by CLIMBER-2 model results, the close connection of millennial-scale sea-level changes to Northern Hemisphere temperature variations indicates a primary climatic control on the mass balance of the major Northern Hemisphere ice sheets and does not require a considerable Antarctic contribution.

(Table 1) Age determination of Chukchi Sea sediments

Dinocysts from cores collected in the Chukchi Sea from the shelf edge to the lower slope were used to reconstruct changes in sea surface conditions and sea ice cover using modern analogue techniques. Holocene sequences have been recovered in a down-slope core (B15: 2135 m, 75°44'N, sedimentation rate of ~1 cm/kyr) and in a shelf core (P1: 201 m, 73°41'N, sedimentation rate of ~22 cm/kyr). The shelf record spanning about 8000 years suggests high-frequency centennial oscillations of sea surface conditions and a significant reduction of the sea ice at circa 6000 and 2500 calendar (cal) years B.P. The condensed offshore record (B15) reveals an early postglacial optimum with minimum sea ice cover prior to 12,000 cal years B.P., which corresponds to a terrestrial climate optimum in Bering Sea area. Dinocyst data indicate extensive sea ice cover (>10 months/yr) from 12,000 to 6000 cal years B.P. followed by a general trend of decreasing sea ice and increasing sea surface salinity conditions, superimposed on large-amplitude millennial-scale oscillations. In contrast, d18O data in mesopelagic foraminifers (Neogloboquadrina pachyderma) and benthic foraminifers (Cibicides wuellerstorfi) reveal maximum subsurface temperature and thus maximum inflow of the North Atlantic water around 8000 cal years B.P., followed by a trend toward cooling of the subsurface to bottom water masses. Sea-surface to subsurface conditions estimated from dinocysts and d18O data in foraminifers thus suggest a decoupling between the surface water layer and the intermediate North Atlantic water mass with the existence of a sharp halocline and a reverse thermocline, especially before 6000 years B.P. The overall data and sea ice reconstructions from core B15 are consistent with strong sea ice convergence in the western Arctic during the early Holocene as suggested on the basis of climate model experiments including sea ice dynamics, matching a higher inflow rate of North Atlantic Water.

Radiocarbon dating, carbon storage and soil properties of samples from Tulemalu Lake, central Canadian Arctic

We investigated total storage and landscape partitioning of soil organic carbon (SOC) in continuous permafrost terrain, central Canadian Arctic. The study is based on soil chemical analyses of pedons sampled to 1 m depth at 35 individual sites along three transects. Radiocarbon dating of cryoturbated soil pockets, basal peat and fossil wood shows that cryoturbation processes have been occurring since the Middle Holocene and that peat deposits started to accumulate in a forest-tundra environment where spruce was present (~6000 cal yrs BP). Detailed partitioning of SOC into surface organic horizons, cryoturbated soil pockets and non-cryoturbated mineral soil horizons is calculated (with storage in active layer and permafrost calculated separately) and explored using principal component analysis. The detailed partitioning and mean storage of SOC in the landscape are estimated from transect vegetation inventories and a land cover classification based on a Landsat satellite image. Mean SOC storage in the 0-100 cm depth interval is 33.8 kg C/m**2, of which 11.8 kg C/m**2 is in permafrost. Fifty-six per cent of the total SOC mass is stored in peatlands (mainly bogs), but cryoturbated soil pockets in Turbic Cryosols also contribute significantly (17%). Elemental C/N ratios indicate that this cryoturbated soil organic matter (SOM) decomposes more slowly than SOM in surface O-horizons.

Bulk density, ash content, humification, peat accumulation and selected lithogenic data of Store Mosse peat bog

This datafile presents chemical and physical as well as age dating information from the Store Mosse peat bog in southern Sweden. This record dates back to 8900 cal yr BP. The aim of the research was to reconstruct mineral dust deposition over time. As such we have only presented the lithogenic element data (Al, Ga, Rb, Sc, Ti, Y, Zr, Th and the REE) as the sample preparation method was tailored to these. This data is supported by parameters describing the deposit including bulk density, humification, ash content and net peat accumulation rates.

(Table 1) Age determination of sediment core PC17

We have investigated glacial-interglacial differences in sea surface temperature (SST) near Hawaii using two relatively high deposition rate, shallow-water piston cores collected near Oahu, Hawaii. Modern hydrographic data show that local surface water temperatures are broadly consistent with the regional pattern of SSTs in the southern subtropical North Pacific. Past SSTs were estimated on the basis of three independently measured parameters: (1) UK'37 values of alkenones, (2) d18O of Globigerinoides ruber, and (3) assemblages of planktonic foraminifera using the modern analog technique (MAT). The two cores yield similar SST records, and if differences in the ecology of foraminifera and coccolithophores are considered, the three different approaches to estimating SSTs yield consistent results. UK'37-based temperatures, which may represent winter values at this location, were ~2.5°C colder during the Last Glacial Maximum than today, which is consistent with the February MAT estimates. The d18O-based temperature estimates, likely biased toward summer temperatures, indicate that the glacial SSTs were at least 1°C cooler than today, which is comparable to the results of MAT August estimates.

Planktic foraminifera isotopes, temperature and d18O of seawater at the central Walvis Ridge for Termination II (MIS 6 to 5), sediment core 64PE-174P13

Salty and warm Indian Ocean waters enter the South Atlantic via the Agulhas leakage, south of Africa. Model simulations and proxy evidence of Agulhas leakage strengthening during glacial terminations led to the hypothesis that it was an important modulator of the Atlantic Ocean circulation. Yet, the fate of the leakage salinity and temperature anomalies remains undocumented beyond the southern tip of Africa. Downstream of the leakage, new paleoceanographic evidence from the central Walvis Ridge (southeast Atlantic) shows that salinity increased at the thermocline, and less so at the surface, during glacial termination II. Thermocline salinity change coincided with higher frequency of Agulhas rings passage at the core location and with salinity maxima in the Agulhas leakage area, suggesting that leakage waters were incorporated in the Atlantic circulation through the thermocline. Hydrographic changes at the Walvis Ridge and in the leakage area display a distinct two-step structure, with a reversal at ca. 134 ka. This matched a wet interlude within the East Asia weak monsoon interval of termination II, and a short-lived North Atlantic warming. Such concurrence points to a Bølling-Allerød-like recovery of the Atlantic circulation amidst termination II, with a northward shift of the Intertropical Convergence Zone and Southern Hemisphere westerlies, and attendant curtailment of the interocean connection south of Africa.

Age-dependence of cultured pearl grade and colour in the black-lipped pearl oyster Pinctada margaritifera

Pinctada margaritifera is an economically important marine bivalve species for cultured pearl production in French Polynesian aquaculture. In order to evaluate the influence of donor oyster age on pearl quality traits, experiments were conducted over 6 years using both grafts and surgreffe operations. At harvest, 6 pearl quality traits were recorded and compared: surface defects, luster, grade, darkness level, and visual color. Analyzing the quality traits of pearls harvested in the initial graft process and those of pearls obtained from surgreffe experiments allowed a comparison of the influence of pearl sac cells originating from the initial mantle graft, which aged together with their recipient oysters. The results demonstrated a significant decrease between these successive grafts in luster, grade (A-B-C,) darkness level, and green color – traits that are of major importance in the pearl market. The duplicated graft experiment allowed the comparison of donor oyster families at 2 and 5 years old, where a mantle graft was inserted into recipient oysters aged 2.5 years old. The results showed the same tendencies to a lesser extent, with 1) an improved pearl grade, predominantly through a most important rate of 0 surface defect category, and 2) a green / grey ratio in favor of the younger donor. A comparison between the graft-surgreffe and the duplicated graft experiments also highlighted: 1) the indirect role played by the younger recipient oysters, which must be optimized for optimal pearl quality realization, and 2) the complex interplay between donor and recipient oysters.

Prevalence of non-communicable diseases in Brazilian children: follow-up at school age of two Brazilian birth cohorts of the 1990's

Background: Few cohort studies have been conducted in low and middle-income countries to investigate non-communicable diseases among school-aged children. This article aims to describe the methodology of two birth cohorts, started in 1994 in Ribeirao Preto (RP), a more developed city, and in 1997/98 in Sao Luis (SL), a less developed town. Methods: Prevalences of some non-communicable diseases during the first follow-up of these cohorts were estimated and compared. Data on singleton live births were obtained at birth (2858 in RP and 2443 in SL). The follow-up at school age was conducted in RP in 2004/05, when the children were 9-11 years old and in SL in 2005/06, when the children were 7-9 years old. Follow-up rates were 68.7% in RP (790 included) and 72.7% in SL (673 participants). The groups of low (<2500 g) and high (>= 4250 g) birthweight were oversampled and estimates were corrected by weighting. Results: In the more developed city there was a higher percentage of non-nutritive sucking habits (69.1% vs 47.9%), lifetime bottle use (89.6% vs 68.3%), higher prevalence of primary headache in the last 15 days (27.9% vs 13.0%), higher positive skin tests for allergens (44.3% vs 25.3%) and higher prevalence of overweight (18.2% vs 3.6%), obesity (9.5% vs 1.8%) and hypertension (10.9% vs 4.6%). In the less developed city there was a larger percentage of children with below average cognitive function (28.9% vs 12.2%), mental health problems (47.4% vs 38.4%), depression (21.6% vs 6.0%) and underweight (5.8% vs 3.6%). There was no difference in the prevalence of bruxism, recurrent abdominal pain, asthma and bronchial hyperresponsiveness between cities. Conclusions: Some non-communicable diseases were highly prevalent, especially in the more developed city. Some high rates suggest that the burden of non-communicable diseases will be high in the future, especially mental health problems.