(Tables S1,2) Stable isotopes in muscle tissue of polar bears (Ursus maritimus) from various regions of the Arctic

The relative contribution of regional contamination versus dietary differences to geographic variation in polar bear (Ursus maritimus) contaminant levels is unknown. Dietary variation between Alaska, Canada, East Greenland, and Svalbard subpopulations was assessed by muscle nitrogen and carbon stable isotope (d15N, d13C) and adipose fatty acid (FA) signatures relative to their main prey (ringed seals). Western and southern Hudson Bay signatures were characterized by depleted d15N and d13C, lower proportions of C20 and C22 monounsaturated FAs and higher proportions of C18 and longer chain polyunsaturated FAs. East Greenland and Svalbard signatures were reversed relative to Hudson Bay. Alaskan and Canadian Arctic signatures were intermediate. Between-subpopulation dietary differences predominated over interannual, seasonal, sex, or age variation. Among various brominated and chlorinated contaminants, diet signatures significantly explained variation in adipose levels of polybrominated diphenyl ether (PBDE) flame retardants (14-15%) and legacy PCBs (18-21%). However, dietary influence was contaminant class-specific, since only low or nonsignificant proportions of variation in organochlorine pesticide (e.g., chlordane) levels were explained by diet. Hudson Bay diet signatures were associated with lower PCB and PBDE levels, whereas East Greenland and Svalbard signatures were associated with higher levels. Understanding diet/food web factors is important to accurately interpret contaminant trends, particularly in a changing Arctic.

Ultimate and failure strengths of normal muds and serpentinite muds of ODP Leg 125 samples

Serpentinite seamounts in the Mariana forearc have been explained as diapirs rising from the Benioff zone. This hypothesis predicts that the serpentinites should have low strengths as well as low densities relative to the surrounding rocks. Drilling during Leg 125 showed that the materials forming Conical Seamount in the Mariana forearc and Torishima Forearc Seamount in the Izu-Bonin forearc are water-charged serpentinite muds of density <2 g/cm**3. Wykeham-Farrance torsion-vane tests showed that they are plastic solids with a rheology that bears many similarities to the idealized Cam clay soil model and is well described by critical-state soil mechanics. The serpentinite muds have ultimate strengths of 1.3 to 273.7 kPa and yield strengths of approximately 1.0 to 50 kPa. These muds thus are orders of magnitude weaker than salt and are, in fact, comparable in density and strength to common deep-sea clay muds. Such weak and low-density materials easily become diapiric. Serpentinite muds from the summit of Conical Seamount are weaker and more ductile than those on its flanks or on Torishima Forearc Seamount. Moreover, the summit muds do not contain the pronounced pure- and simple-shear fabrics that characterize those on the seamount flanks. The seamounts are morphologically similar to shield volcanoes, and anastomosing serpentinite debris flows descending from their summits are similar in map view to pahoehoe flows. These morphologic features, together with the physical properties of the muds and their similarities to other oceanic muds and the geochemistry of the entrained waters, suggest that many forearc serpentinite seamounts are gigantic (10-20 km wide, 1.5-2.0 km high) mud volcanoes that formed by the eruption of highly liquid serpentinite muds. Torishima Forearc Seamount, which is blanketed by more ìnormalî pelagic/volcaniclastic sediment, has probably been inactive since the Miocene. Conical Seamount, which seems to consist entirely of serpentinite mud and is venting fresh water of unusual chemistry from its summit, is presently active. Muds from the flanks of Conical Seamount are stronger and more brittle than those from the summit site, and muds from Torishima Forearc Seamount are stronger yet; this suggests that the serpentinite debris flows are compacted and dewatered as they mature. The shear fabrics probably result from downslope creep and flow, but may also be inherited.

Stable carbon and oxygen isotope compositions of benthic foraminifera N. truempyi samples and coarse fraction analyses from ODP Site 198-1209

We have compiled the first stratigraphically continuous high-resolution benthic foraminiferal stable isotope record for the Paleocene from a single site utilizing cores recovered at Pacific ODP Site 1209. The long-term trend in the benthic isotope record suggests a close coupling of volcanic CO2 input and deep sea warming. Over the short-term the record is characterized by slow excursions with a pronounced periodic beat related to the short (100-kyr) and long (405-kyr) eccentricity cycle. The phase relationship between the benthic isotope record and eccentricity is similar to patterns documented for the Oligocene and Miocene confirming the role of orbital forcing as the pace maker for paleoclimatic variability on Milankovitch time scales. In addition, the record documents an unusual transient warming of 2°C coeval with a 0.6 per mil carbon isotope excursion and a decrease in carbonate content at 61.75 Ma. This event, which bears some resemblance to Eocene hyperthermals, marks the onset of a long-term decline in d13C. The timing indicates it might be related to the initiation of volcanism along Greenland margin.

Grain entrainment and transport rates of magnetic minerals of coastal sediment samples from the Bay of Plenty, New Zealand

Heavy (magnetic & non-magnetic) minerals are found concentrated by natural processes in many fluvial, estuarine, coastal and shelf environments with a potential to form economic placer deposits. Understanding the processes of heavy mineral transport and enrichment is prerequisite to interpret sediment magnetic properties in terms of hydro- and sediment dynamics. In this study, we combine rock magnetic and sedimentological laboratory measurements with numerical 3D discrete element models to investigate differential grain entrainment and transport rates of magnetic minerals in a range of coastal environments (riverbed, mouth, estuary, beach and near-shore). We analyzed grain-size distributions of representative bulk samples and their magnetic mineral fractions to relate grain-size modes to respective transport modes (traction, saltation, suspension). Rock magnetic measurements showed that distribution shapes, population sizes and grain-size offsets of bulk and magnetic mineral fractions hold information on the transport conditions and enrichment process in each depositional environment. A downstream decrease in magnetite grain size and an increase in magnetite concentration was observed from riverine source to marine sink environments. Lower flow velocities permit differential settling of light and heavy mineral grains creating heavy mineral enriched zones in estuary settings, while lighter minerals are washed out further into the sea. Numerical model results showed that higher heavy mineral concentrations in the bed increased the erosion rate and enhancing heavy mineral enrichment. In beach environments where sediments contained light and heavy mineral grains of equivalent grain sizes, the bed was found to be more stable with negligible amount of erosion compared to other bed compositions. Heavy mineral transport rates calculated for four different bed compositions showed that increasing heavy mineral content in the bed decreased the transport rate. There is always a lag in transport between light and heavy minerals which increases with higher heavy mineral concentration in all tested bed compositions. The results of laboratory experiments were validated by numerical models and showed good agreement. We demonstrate that the presented approach bears the potential to investigate heavy mineral enrichment processes in a wide range of sedimentary settings.

A time-slice study in Heinrich Stadial 1 and Mid Holocene sediment cores off northern Senegal

Sediment dynamics in limnic, fluvial and marine environments can be assessed by granulometric and rock-magnetic methodologies. While classical grain-size analysis by sieving or settling mainly bears information on composition and transport, the magnetic mineral assemblages reflect to a larger extent the petrology and weathering conditions in the sediment source areas. Here, we combine both methods to investigate Late Quaternary marine sediments from five cores along a transect across the continental slope off Senegal. This region near the modern summer Intertropical Convergence Zone is particularly sensitive to climate change and receives sediments from several aeolian, fluvial and marine sources. From each of the investigated five GeoB sediment cores (494-2956 m water depth) two time slices were processed which represent contrasting climatic conditions: the arid Heinrich Stadial 1 (~ 15 kyr BP) and the humid Mid Holocene (~ 6 kyr BP). Each sediment sample was split into 16 grain-size fractions ranging from 1.6 to 500 µm. Concentration and grain-size indicative magnetic parameters (susceptibility, SIRM, HIRM, ARM and ARM/IRM) were determined at room temperature for each of these fractions. The joint consideration of whole sediment and magnetic mineral grain-size distributions allows to address several important issues: (i) distinction of two aeolian sediment fractions, one carried by the north-easterly trade winds (40-63 µm) and the other by the overlying easterly Harmattan wind (10-20 µm) as well as a fluvial fraction assigned to the Senegal River (< 10 µm); (ii) identification of three terrigenous sediment source areas: southern Sahara and Sahel dust (low fine-grained magnetite amounts and a comparatively high haematite content), dust from Senegalese coastal dunes (intermediate fine-grained magnetite and haematite contents) and soils from the upper reaches of the Senegal River (high fine-grained magnetite content); (iii) detection of partial diagenetic dissolution of fine magnetite particles as a function of organic input and shore distance; (iv) analysis of magnetic properties of marine carbonates dominating the grain-size fractions 63-500 µm.

A reconstruction of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the glacial inception

The reconstruction of the stable carbon isotope evolution in atmospheric CO2 (d13Catm ), as archived in Antarctic ice cores, bears the potential to disentangle the contributions of the different carbon cycle fluxes causing past CO2 variations. Here we present a new record of d13Catm before, during and after the Marine Isotope Stage 5.5 (155 000 to 105 000 years BP). The record was derived with a well established sublimation method using ice from the EPICA Dome C (EDC) and the Talos Dome ice cores in East Antarctica. We find a 0.4 permil shift to heavier values between the mean d13Catm level in the Penultimate (~ 140 000 years BP) and Last Glacial Maximum (~ 22 000 years BP), which can be explained by either (i) changes in the isotopic composition or (ii) intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii) by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 years, but with different phasing and magnitudes. Furthermore, a 5000 years lag in the CO2 decline relative to EDC temperatures is confirmed during the glacial inception at the end of MIS 5.5 (120 000 years BP). Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.

Geochemistry and mineralogy of garnet grains from ODP Sample 183-1137A-33R-3,50-53

On Elan Bank, a southwestern promontory of the Kerguelen Plateau in the southern Indian Ocean, we cored an interval of conglomerate and minor sandstone within a thick section of Cretaceous flood basalts. Most of the detritus in these sedimentary rocks is volcanic with the exception of a small amount of conspicuous material of probable continental derivation. The anomalous clasts include several pebbles of gneiss (Nicolaysen et al., 2001, doi:10.1130/0091-7613(2001)029<0235:POPGBG>2.0.CO;2) and garnet sand grains. The presence of continental material on the plateau bears significantly on the interpretation of Indian Ocean basalts (Weis et al., 2001, doi:10.1130/0091-7613(2001)029<0147:OOCCII>2.0.CO;2). The purpose of the present study was to determine the composition of the garnets to provide additional constraints on the nature of the source area.

(Table 2) Seroprevalence against Trichinella spp. in Ursus maritimus from Svalbard and Barents Sea pack ice

Blood samples of live-caught polar bears (Ursus maritimus) from Svalbard collected 1991-2000 (Period 1) and 2006-2008 (Period 2) and from the pack ice of the Barents Sea collected in Period 1, were assayed for antibodies against Trichinella spp. by ELISA. Of 54 cubs-of-the-year included in the Period 1 sample, 53 were seronegative, indicating that exposure to Trichinella infected meat is uncommon during the first months of life for polar bears in the Svalbard region. Of 30 mother-offspring pairs, 18 mothers were seropositive with seronegative offspring (n = 27), suggesting (1) that maternal antibodies had dropped to levels below detection limit by the time of capture in April (offspring approximately 4 months old), and (2) supporting experimental studies in other animal models showing that vertical transmission of Trichinella spp. is uncommon. Bear 1 year and older had higher prevalence in Svalbard (78%) than in the Barents Sea (51%). There was no temporal change in prevalence for bears from Svalbard during the time between the two periods. The prevalence increased with age in both sexes. A positive correlation was found between anti-Toxoplasma gondii and anti-Trichinella spp. antibodies.

Geochemistry of ODP Hole 135-841B

Two igneous rock units were recovered at Site 841. More than 200 m of island-arc rhyolites, rhyolitic tuffs, lapilli tuffs, and pumice breccias, divided into five units, compose the basement at the site. These rhyolitic volcanics are late middle Eocene or older and formed part of a subaerial rhyolitic volcano. These low-K rhyolites were produced by fractional crystallization of a more mafic arc-tholeiitic lava or by dehydration melting of lower crustal arc tholeiites. The Site 841 basement rocks are similar in composition to high-SiO2 lavas in the Eocene basement on 'Eua and crystallized from depleted island-arc-tholeiitic basalts like those exposed on 'Eua. No evidence is present in the rhyolites, or in the clasts enclosed within them, for boninite series magmas at Site 841. The Site 841 rhyolitic complex bears no resemblance to Cretaceous rhyolites from the Lord Howe Rise, which are enriched in K and incompatible elements. The volcanic rocks at Site 841 are part of a widely distributed Eocene volcanic episode that marked the earliest phases of subduction in the Tonga region; they are not part of an older crustal fragment. The second igneous sequence is a series of basaltic dikes and sills that intruded Miocene sediments. These basalts have trace element abundances and ratios identical to upper Miocene lavas from the Lau Ridge. The Site 841 basalts do not have any geochemical characteristics that suggest they were generated by unusual thermal conditions in the shallow sub-forearc mantle. They are most reasonably interpreted as intrusions fed by basement dikes propagated from the associated active arc. No evidence for local serpentinite exposures, like those that are common in the Mariana forearc, was found at Site 841. The results from Site 841 provide strong support for hypotheses of forearc evolution that have been advanced for the Izu-Bonin-Mariana system.

(Table 3) Liver weight, blood liver parameters, and blood plasma PCB concentrations in 14 sledge dog bitches and their 14 pups in Aasiaat, west Greenland

We assessed the relationship between exposure to organohalogen polluted minke whale (Balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 Greenland sledge dogs (Canis familiaris). The prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all Chi-square: p<0.05). In case of granulomas, the frequency was significantly highest in the bitches (P generation) while the prevalence of portal fibrosis was highest in the F generation (pups) (both Chi-square: p<0.05). No significant difference between exposed and controls was found for bile acid, ALAT, and ALKP, while ASAT and LDH were significantly highest in the control group (both ANOVA: p<0.05). We therefore suggest that a daily intake of 50-200 g environmentally organohalogen polluted minke whale blubber can cause liver lesions in Greenland sledge dogs. It is reasonable to infer that other apex predators such as polar bears (Ursus maritimus) and humans may suffer from similar impacts.

(Table 1) Neutral and phenolic organohalogen compounds in blubber samples of ringed seals (Pusa hispida) from East Greenland

We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants and metabolic by-products: polychlorinated biphenyls (PCBs), chlordanes (CHLs), hydroxyl (OH-) and methylsulfonyl (MeSO2-) PCBs, polybrominated biphenyls (PBBs), OH-PBBs, polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) flame retardants and OH- and methoxyl (MeO-) PBDEs, 2,2-dichloro-bis(4-chlorophenyl)ethene (p,p'-DDE), 3-MeSO2-p,p'-DDE, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS). We detected all of the investigated contaminants in ringed seal blubber with high frequency, the main diet of East Greenland bears, with the exception of OH-PCBs and 4-OH-HpCS, which indicated that these phenolic contaminants were likely of metabolic origin and formed in the bears from accumulated PCBs and octachlorostyrene (OCS), respectively, rather than being bioaccumulated from a seal blubber diet. For all of the detectable sum of classes or individual organohalogens, in general, the ringed seal to polar bear mean BMFs for SumPCBs, p,p'-DDE, SumCHLs, SumMeSO2-PCBs, 3-MeSO2-p,p'-DDE, PCP, SumPBDEs, total-(alpha)-HBCD, SumOH-PBDEs, SumMeO-PBDEs and SumOH-PBBs indicated that these organohalogens bioaccumulate, and in some cases there was tissue-specific biomagnification, e.g., BMFs for bear adipose and liver ranged from 2 to 570. The blood-brain barrier appeared to be effective in minimizing brain accumulation as BMFs were <= 1 in the brain, with the exception of SumOH-PBBs (mean BMF = 93±54). Unlike OH-PCB metabolites, OH-PBDEs in the bear tissues appeared to be mainly accumulated from the seal blubber rather than being metabolic formed from PBDEs in the bears. In vitro PBDE depletion assays using polar bear hepatic microsomes, wherein the rate of oxidative metabolism of PBDE congeners was very slow, supported the probability that accumulation from seals is the main source of OH-PBDEs in the bear tissues. Our findings demonstrated from ringed seal to polar bears that organohalogen biotransformation, bioaccumulation and/or biomagnification varied widely and depended on the contaminant in question. Our results show the increasing complexity of bioaccumulated and in some cases biomagnified, chlorinated and brominated contaminants and/or metabolites from the diet may be a contributing stress factor in the health of East Greenland polar bears.

(Table 1) 10 Beryllium and CaCO3 at DSDP Holes 86-576B, 86-576, and 86-578

Extension of the 10Be geochronology for deep-sea sediments beyond the limit of late Pliocene age found in published works has been attempted. The results obtained on sediments from Deep Sea Drilling Project (DSDP) Sites 576 and 578 of Leg 86 suggest the feasibility of dating sediments as old as 12 to 15 m.y. At both sites, there have been large changes in sedimentation rate, with the Pleistocene sediments accumulating several times faster than those of the Pliocene, which in turn were deposited several times more rapidly than the late Miocene sediments. The Pleistocene-Pliocene section is considerably thicker in Hole 578 than in Hole 576B: the respective depths for the 7 m.y. time boundary in the two holes are about 125 and about 25 m. These 10Be-based age estimates are in agreement with the paleomagnetic stratigraphies established for the two sites. The suggested enhancement in the oceanic deposition of 10Be before 7 to 9 m.y. ago, as noticed in manganese crusts, has found tentative support from the present sedimentary records. A preliminary search for 10Be production variation during a geomagnetic field reversal has been conducted. In Hole 578, an enhanced 10Be concentration is found in a sample close to the Brunhes/Matuyama reversal boundary. More detailed and systematic measurements are required to confirm this observation, which bears on the detailed behavior of the geomagnetic field during the reversal.