Calcareous nannofossils in ODP Hole 131-808C

ODP Leg 131 recovered nannofossil-bearing sediments from Site 808 in the Nankai Trough, western Pacific Ocean. Three holes were examined for nannofossils, 808A, 808B, and 808C. A total of 22 nannofossil events were recognized, of which 10 are used as zonal markers. The sediments recovered from Hole 808A (0-111.4 mbsf) contain Pleistocene nannofossil assemblages that are mostly well preserved. All samples from this hole were assigned to nannofossil Zone NN21. The nannofossil assemblages observed in Hole 808B (111.0-358.8 mbsf) are poorly to well preserved and were all assigned to the Pleistocene. The NN21/NN20 Boundary is placed at 230.7 ± 4.4 mbsf. Hole 808C was cored from 298.5 to 1327 mbsf and basalt was reached at 1289.9 mbsf. The sediments recovered range in age from the upper part of Zone NN20 of the Pleistocene to Zone NN5 of the middle Miocene and contain poorly to well-preserved nannofossil assemblages. The Pliocene/Pleistocene Boundary, marked by the FO Gephyrocapsa caribbeanica, was placed at 776.3 ±1.6 mbsf, and the Miocene/Pliocene Boundary is tentatively placed at 955.9 ±1.5 mbsf. The lowermost sediments above basement as well as a sediment sample intercalated between basalt flows are assigned to Zone NN5, with an age of approximately 15 Ma. Age estimates provided by nannofossils show that the sedimentation rate in the trench-fill deposits of the Nankai Trough was very high, 800-1350 m/m.y (0-0.46 Ma), whereas in the Shikoku Basin deposits (> 0.46 Ma), the sedimentation rate was much lower (24-200 m/m.y). These age estimates also provide an extrapolated age of approximately 15 Ma for the basaltic basement at Site 808.

Snow height on sea ice and sea ice drift from autonomous measurements from buoy 2015S22, deployed during the Norwegian Young sea ICE cruise (N-ICE 2015) project

Snow height was measured by the Snow Depth Buoy 2015S22, an autonomous platform, drifting on Arctic sea ice, deployed during the Norwegian Young sea ICE cruise (N-ICE 2015) project. The resulting time series describes the evolution of snow depth as a function of place and time between 2015-03-01 and 2015-05-06 in sample intervals of 1 hour. The Snow Depth Buoy consists of four independent sonar measurements representing the area (approx. 10 m**2) around the buoy. The buoy was installed on first year ice. In addition to snow depth, geographic position (GPS), barometric pressure, air temperature, and ice surface temperature were measured. Negative values of snow depth occur if surface ablation continues into the sea ice. Thus, these measurements describe the position of the sea ice surface relative to the original snow-ice interface. Differences between single sensors indicate small-scale variability of the snow pack around the buoy. The data set has been processed, including the removal of obvious inconsistencies (missing values). Records without any snow depth may still be used for sea ice drift analyses.

Nicotinamide nucleotide and adenylate concentrations in mante, siphon and gill tissue of old and young Laternula elliptica individuals under control and experimental conditions

Future oceans are predicted to contain less oxygen than at present. This is because oxygen is less soluble in warmer water and predicted stratification will reduce mixing. Hypoxia in marine environments is thus likely to become more widespread in marine environments and understanding species-responses is important to predicting future impacts on biodiversity. This study used a tractable model, the Antarctic clam, Laternula elliptica, which can live for 36 years, and has a well-characterized ecology and physiology to understand responses to hypoxia and how the effect varied with age. Younger animals had a higher condition index, higher adenylate energy charge and transcriptional profiling indicated that they were physically active in their response to hypoxia, whereas older animals were more sedentary, with higher levels of oxidative damage and apoptosis in the gills. These effects could be attributed, in part, to age-related tissue scaling; older animals had proportionally less contractile muscle mass and smaller gills and foot compared with younger animals, with consequential effects on the whole-animal physiological response. The data here emphasize the importance of including age effects, as large mature individuals appear to be less able to resist hypoxic conditions and this is the size range that is the major contributor to future generations. Thus, the increased prevalence of hypoxia in future oceans may have marked effects on benthic organisms' abilities to persist and this is especially so for long-lived species when predicting responses to environmental perturbation.