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Quantifying the opal belt in the Atlantic and southeast Pacific sector of the Southern Ocean by means of 230 Th normalization
Author(s) -
Geibert Walter,
Rutgers van der Loeff Michiel M.,
Usbeck Regina,
Gersonde Rainer,
Kuhn Gerhard,
SeebergElverfeldt Jens
Publication year - 2005
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2005gb002465
Subject(s) - ocean gyre , geology , oceanography , biogenic silica , sediment , flux (metallurgy) , sedimentation , pacific ocean , sediment trap , pelagic zone , indian ocean , thermohaline circulation , water column , geomorphology , subtropics , materials science , fishery , metallurgy , biology
A set of 114 samples from the sediment surface of the Atlantic, eastern Pacific and western Indian sectors of the Southern Ocean has been analyzed for 230 Th and biogenic silica. Maps of opal content, Th‐normalized mass flux, and Th‐normalized biogenic opal flux into the sediment have been derived. Significant differences in sedimentation patterns between the regions can be detected. The mean bulk vertical fluxes integrated into the sediment in the open Southern Ocean are found in a narrow range from 2.9 g m −2 yr −1 (Eastern Weddell Gyre) to 15.8 g m −2 yr −1 (Indian sector), setting upper and lower limits to the vertically received fraction of open ocean sediments. The silica flux to sediments of the Atlantic sector of the Southern Ocean is found to be 4.2 ± 1.4 × 10 11 mol yr −1 , just one half of the last estimate. This adjustment represents 6% of the output term in the global marine silica budget.