(Table 1) Circulating levels of TT3 and TT4, and age, length, girth, and estimated body mass in polar bears (Ursus maritimus) from East Greenland 1999-2001

We investigated the multivariate relationships between adipose tissue residue levels of 48 individual organohalogen contaminants (OHCs) and circulating thyroid hormone (TH) levels in polar bears (Ursus maritimus) from East Greenland (1999-2001, n = 62), using projection to latent structure (PLS) regression for four groupings of polar bears; subadults (SubA), adult females with cubs (AdF_N), adult females without cubs (AdF_S) and adult males (AdM). In the resulting significant PLS models for SubA, AdF_N and AdF_S, some OHCs were especially important in explaining variations in circulating TH levels: polybrominated diphenylether (PBDE)-99, PBDE-100, PBDE-153, polychlorinated biphenyl (PCB)-52, PCB-118, cis-nonachlor, trans-nonachlor, trichlorobenzene (TCB) and pentachlorobenzene (QCB), and both negative and positive relationships with THs were found. In addition, the models revealed that DDTs had a positive influence on total 3,5,3'-triiodothyronine (TT3) in AdF_S, and that a group of 17 higher chlorinated ortho-PCBs had a positive influence on total 3,5,3',5'-tetraiodothyronine (thyroxine, TT4) in AdF_N. TH levels in AdM seemed less influenced by OHCs because of non-significant PLS models. TH levels were also influenced by biological factors such as age, sex, body size, lipid content of adipose tissue and sampling date. When controlling for biological variables, the major relationships from the PLS models for SubA, AdF_N and AdF_S were found significant in partial correlations. The most important OHCs that influenced TH levels in the significant PLS models may potentially act through similar mechanisms on the hypothalamic-pituitary-thyroid (HPT) axis, suggesting that both combined effects by dose and response addition and perhaps synergistic potentiation may be a possibility in these polar bears. Statistical associations are not evidence per se of biological cause-effect relationships. Still, the results of the present study indicate that OHCs may affect circulating TH levels in East Greenland polar bears, adding to the "weight of evidence" suggesting that OHCs might interfere with thyroid homeostasis in polar bears.

P-wave velocities and applied bed thickness and velocity changes for synthetic seismograms, ODP Leg 188 and Leg 119 sites

Synthetic seismograms provide a crucial link between lithologic variations within a drill hole and reflectors on seismic profiles crossing the site. In essence, they provide a ground-truth for the interpretation of seismic data. Using a combination of core and logging data, we created synthetic seismograms for Ocean Drilling Program Sites 1165 and 1166, drilled during Leg 188, and Site 742, drilled during Leg 119, all in Prydz Bay, Antarctica. Results from Site 1165 suggest that coring penetrated a target reflector initially thought to represent the onset of drift sedimentation, but the lithologic change across the boundary does not show a change from predrift to drift sediments. The origin of a shallow reflector packet in the seismic line across Site 1166 and a line connecting Sites 1166 and 742 was resolved into its constituent sources, as this reflector occurs in a region of large-scale, narrowly spaced impedance changes. Furthermore, Site 1166 was situated in a fluvio-deltaic system with widely variable geology, and bed thickness changes were estimated between the site and both seismic lines.

Petrology and geochemistry of the AND-1B Core

Petrologic descriptions will follow a division related to both grain size and lithology like that adopted in Cape Roberts investigation (Cape Roberts Science Team 2000, hdl:10013/epic.28287.d001, and references therein). First, we describe the petrology of the sand fraction of the core. Second, we report the distribution of clasts with diameter larger than 2 millimeter (mm) and the petrology of basement clasts. Third, we focus on the occurrence and petrology of McMurdo Volcanic Group sediments, which represent the largest component in the core. The final section continues with the compositional characterization of bulk sediments by continuous X-ray fluorescence measurement (XRF scan) integrated by carbonate geochemistry and concludes with the porewater geochemistry. All of these data will contribute to infer palaeoclimatic information and to understand provenance history of detritus, changes in depositional environment, and spatial and temporal evolution of magmatism in McMurdo Ice Shelf area.

Geochemistry of tropical Atlantic sediments of Marine Isotope Stage 4

Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water (SAMW) are the main conduits for the supply of dissolved silicon (silicic acid) from the deep Southern Ocean (SO) to the low-latitude surface ocean and therefore have an important control on low-latitude diatom productivity. Enhanced supply of silicic acid by AAIW (and SAMW) during glacial periods may have enabled tropical diatoms to outcompete carbonate-producing phytoplankton, decreasing the relative export of inorganic to organic carbon to the deep ocean and lowering atmospheric pCO2. This mechanism is known as the "silicic acid leakage hypothesis" (SALH). Here we present records of neodymium and silicon isotopes from the western tropical Atlantic that provide the first direct evidence of increased silicic acid leakage from the Southern Ocean to the tropical Atlantic within AAIW during glacial Marine Isotope Stage 4 (~60-70 ka). This leakage was approximately coeval with enhanced diatom export in the NW Atlantic and across the eastern equatorial Atlantic and provides support for the SALH as a contributor to CO2 drawdown during full glacial development.

Geological map of VIKENEGGA, Heimefrontfjella, Antarctica (Scale 1:25,000)

Topographic data of this geological map were obtained through stereoscopic aerial photo interpretation. The photogrammetric photo flights were undertaken in 1986 by the Institut für Angewandte Geodäsie, Frankfurt. Horizontal ground control points required for aerial photo interpretation were determined by means of Doppler satellite observation during the 2nd German Neuschwabenland Expedition 1985/86. Vertical ground control points were taken from unpublished map drafts at 1:100 000 scale by Norsk Polarinstitutt, Oslo. The elevation above mean sea level was transferred to Heimefrontfjella barometrically. For this reason assertions concerning the absolute elevation (referred to sea level) are uncertain. Contours and spot heights presented on the map were obtained from the photogrammetric evaluation of the photography taken in 1986; relative elevation data (hight differences) are accurate to approximately ±10 m.

(Table 1) Trace element and isotopic data for ODP Hole 145-887D basalts

Age-progressive, linear seamount chains in the northeast Pacific appear to have formed as the Pacific plate passed over a set of stationary hotspots; however, some anomalously young ages and the lack of an "enriched" isotopic signature in basalts from the seamounts do not fit the standard hotspot model. For example, published ages (28-30 Ma) for basalts dredged from the Patton-Murray seamount platform in the Gulf of Alaska are 2-4 m.y. younger than the time when the platform was above the Cobb hotspot. However, the lowermost basalt recovered by ocean drilling on Patton-Murray yielded a 40Ar-39Ar age of 33 Ma. This age exactly coincides with the time when the seamount platform was above the Cobb hotspot, consistent with a stationary, long-lived mantle plume. A 27 Ma alkalic basalt flow recovered 8 m above the 33 Ma basalt is similar in age and composition to the previously dredged basalts, and may be the alkalic capping phase typical of many hotspot volcanoes. A 17 Ma tholeiitic basalt sill recovered 5 m above the 27 Ma basalt was emplaced long after the seamount platform moved away from the hotspot, and may be associated with a period of intraplate extension. Anomalously young phases of volcanism on this and other hotspot seamounts suggest that they can be volcanically rejuvenated by nonhotspot causes, but this rejuvenation does not rule out the hotspot model as an explanation for the initial creation of the seamount platform. The lack of an "enriched" isotopic signature in any of these basalts shows that enriched compositions are not necessary characteristics of plume-related basalts. The isotopic compositions of the lower basalts are slightly more depleted than the 0-9 Ma products of the Cobb hotspot, despite the fact that the hotspot was closer to a spreading ridge at 0-9 Ma. It appears that this hotspot, like several others, has become more enriched with time.

(Table 1) Nutrient concentrations and carbon isotopes of sea ice segments and brine sampled during Nathaniel B. Palmer cruises NBP98-07 and NBP06-08, Ross Sea

We examined controls on the carbon isotopic composition of sea ice brines and organic matter during cruises to the Ross Sea, Antarctica in November/December 1998 and November/December 2006. Brine samples were analyzed for salinity, nutrients, total dissolved inorganic carbon (sum CO2), and the 13C/12C ratio of Sum CO2 (d13C(sum CO2)). Particulate organic matter from sea ice cores was analyzed for percent particulate organic carbon (POC), percent total particulate nitrogen (TPN), and stable carbon isotopic composition (d13C(POC)). Sum CO2 in sea ice brines ranged from 1368 to 7149 µmol/kg, equivalent to 1483 to 2519 µmol/kg when normalized to 34.5 psu salinity (s sum CO2), the average salinity of Ross Sea surface waters. Sea ice primary producers removed up to 34% of the available sum CO2, an amount much higher than the maximum removal observed in sea ice free water. Carbonate precipitation and CO2 degassing may reduce s sum CO2 by a similar amount (e.g., 30%) in the most hypersaline sea ice environments, although brine volumes are low in very cold ice that supports these brines. Brine d13C(sum CO2) ranged from -2.6 to +8.0 per mil while d13C(POC) ranged from -30.5 to -9.2 per mil. Isotopic enrichment of the sum CO2 pool via net community production accounts for some but not all carbon isotopic enrichment of sea ice POC. Comparisons of s sum CO2, d13C(sum CO2), and d13C(POC) within sea ice suggest that epsilon p (the net photosynthetic fractionation factor) for sea ice algae is ~8 per mil smaller than the epsilon p observed for phytoplankton in open water regions of the Ross Sea. These results have implications for modeling of carbon uptake and transformation in the ice-covered ocean and for reconstruction of past sea ice extent based on stable isotopic composition of organic matter in sediment cores.