Terrigenous Fe input and biogenic sedimentation in the glacial and interglacial equatorial Pacific Ocean

摘要: Many ocean regions important to the global carbon budget, including equatorial Pacific Ocean, have low chlorophyll concentrations despite high levels of conventional nutrients. Iron may instead be limiting nutrient, and elevated input terrigenous Fe during windy glacial episodes has been hypothesized stimulate oceanic productivity through time thus regulate atmospheric CO2 balance. To test whether particulate is related accumulation biogenic matter in one chlorophyll-high nutrient area, that is, we present results from a suite sediment cores collectively record deposition last six glacial-interglacial cycles (~ 600,000 years). Our data set includes new chemical on total Fe, terrigenous, components three as well previously published mineralogic records colJan region. Chemical, spectral, stratigraphic analysis indicates (1) region shows no consistent pattern either or interglacial maxima, (2) closely (linear r 2 = 0.81 - 0.98), (3) there are coherent spectral relationships between periodicity (i.e., 5180) any orbital frequency bands, (4) linear cross-spectral correlations CaCO3 concentration most commonly strongest observed component, yet indicate largely inverse pattern, with higher being associated CaCO3, (5) correlation coherence Corg, opal. Thus relationship sedimentary sequestering 'carbon. Additionally, although cannot specifically address potential for changes solubility fraction driven by compositional change, Fe/Ti ratio (which monitors first-order changes) only slight variations also linearly spectrally unrelated periodicity, bulk flux, component. Finally, find paleoceanographic flux several order-of-magnitudes larger than modem observations input, suggesting long-term importance dust storms deliver order burial) underestimated. The removal recently discovered source within Equatorial Undercurrent, however, remains unquanfified prove significant.