2026-10-15T08:29:01Z https://oai.datacite.org/oai

doi:10.1594/pangaea.736799 2024-07-21T11:01:33Z PANGAEA PANGAEA.REPOSITORY

Barium concentration in sediments of the central Equatorial Pacific Paytan, Adina Kaster, M PANGAEA 1996 Issued: 1996 doi:10.1016/0012-821x(96)00120-3 Gravity corer TT013 Thomas G. Thompson Joint Global Ocean Flux Study (JGOFS) High resolution pore-water dissolved Ba concentration-depth profiles were determined at seven sites across an Equatorial Pacific productivity gradient from 12°S to 9°N, at 140°W. These data are important for understanding the physical, chemical, and biological controls on Ba recycling in the ocean, and for evaluating the paleo-oceanographic significance of Ba content in central Equatorial Pacific sediments.Pore-water Ba concentrations at all sites are higher than in the overlying bottom water, leading to a diffusive flux of Ba into the ocean. A pronounced subsurface concentration maximum exceeding barite solubility characterizes the dissolved Ba pore-water profiles, suggesting that the Ba regenerated in the upper few millimeters of sediment is not controlled by barite solubility. A few centimeters down-core Ba concentrations reach a relatively constant value of approximately barite saturation.The benthic Ba flux shows a clear zonal trend, with a maximum between 2°S and 2°N, most probably due to higher productivity at the equatorial divergence zone, and with lowest values at the southern and northern extremes of the transect. The dissolved Ba flux between 2°S and 2°N is ~30 nmol/cm**2 yr and drops to 6 nmol/cm**2 yr at 12°S. Even the lowest fluxes are significantly higher than those previously reported for the open ocean. In the Equatorial Pacific the calculated Ba recycling efficiency is about 70%. Thus, ~30% of the particulate Ba flux to the deep ocean is preserved in the sediments, compared with less than 1% for organic carbon and ~5% for biogenic silica.Mass balance calculation of the oceanic Ba cycle, using a two-box model, implies benthic Ba fluxes similar to those reported here for a steady-state ocean. Supplement to: Paytan, Adina; Kaster, M (1996): Benthic Ba fluxes in the central Equatorial Pacific, implications for the ocean Ba cycle. Earth and Planetary Science Letters, 142(3-4), 439-450 en Collection Supplementary Publication Series of Datasets application/zip Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode