Ogasawara winter Sr/Ca and U/Ca data of coral core OGA-02-1 and PDO reconstruction (coral-geoduck index)

The Pacific Decadal Oscillation (PDO), the leading mode of sea surface temperature (SST) anomalies in the extratropical North Pacific Ocean, has widespread impacts on precipitation in the Americas and marine fisheries in the North Pacific. However, marine proxy records with a temporal resolution that resolves interannual to interdecadal SST variability in the extratropical North Pacific are extremely rare. Here we demonstrate that the winter Sr/Ca and U/Ca records of an annually-banded reef coral from the Ogasawara Islands in the western subtropical North Pacific are significantly correlated with the instrumental winter PDO index over the last century. The reconstruction of the PDO is further improved by combining the coral data with an existing eastern mid-latitude North Pacific growth ring record of geoduck clams. The spatial correlations of this combined index with global climate fields suggest that SST proxy records from these locations provide potential for PDO reconstructions further back in time.

Effective stress, porosity, p-wave velocity and mineral composition of ODP Hole 174A-1073A sediments

Porosity, permeability, and compressional (P-wave) velocity were measured as a function of stress on sediments from Ocean Drilling Program Site 1073, U.S. Mid-Atlantic continental slope. Thin sections, scanning electron microscopy, and X-ray diffraction analyses provided mineralogical characteristics of the samples. Uniaxial strain boundary conditions were imposed on the samples during consolidation tests with the maximum effective axial stress reaching 13 MPa. The maximum effective radial stress necessary to maintain uniaxial strain was 7.6 MPa. Over an effective axial stress interval of 0 to 5.2 MPa, Sample 174A-1073A-26X-2, 82-89 cm (226.65 meters below seafloor [mbsf]), exhibited the largest decrease in porosity (51% to 41%), whereas Sample 71X-1, 2-8 cm (644.70 mbsf), exhibited the smallest decrease in porosity (48% to 45%). All samples showed negligible porosity increases during unloading. The permeability (on the order of 1 x 10-17 m**2) of Sample 174A-1073A-71X-1, 2-8 cm, was twice that measured on Sample 8H-1, 23-26 cm (63.75 mbsf), even though the former was considerably deeper and older. The differences in porosity-stress behavior and permeability between shallow and deep samples is related to lithologic, mineralogic, and diagenetic differences between the sediments above and below the Pliocene-Pleistocene to Miocene unconformity. P-wave velocity for Samples 174A-1073A-41X-5, 97-103 cm (372.35 mbsf), and 71X-1, 2-8 cm, increased with decreasing porosity, but did not change significantly during unloading.

Bacterial production in the Aegean Sea in April 2008 during SES_GR1

The HCMR_SES_LAGRANGIAN_GR1_ MICROBIAL PARAMETERS dataset is based on samples collected in the framework of the project SESAME, in the North Aegean Sea during April 2008. The objectives were to measure the standing stocks and calculate the production of the microbial compartment of the food web, describe the vertical distribution pattern and characterize its structure and function through the water column as influenced by the BSW. Bacterial production was estimated by the 3H-leucine method (Kirchman et al. 1986, Kirchman 1993). At each depth, duplicate samples and a control were incubated with 20 nM L-[4,5 3H]-leucine. Samples were incubated in the dark, at in situ temperature.