Application of sediment core modelling to understanding climates of the past: An example from glacial-interglacial changes in Southern Ocean silica cycling

• Main Author: Ridgwell, A.
• Other Authors: School of Geographical Sciences Bristol, University of Bristol Bristol
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarctic; Southern Ocean; The Antarctic; Antarc*; Sea ice
• Online Access: https://hal.science/hal-00298167; https://hal.science/hal-00298167/document; https://hal.science/hal-00298167/file/cpd-2-1371-2006.pdf

International audience Paleoceanographic evidence from the Southern Ocean reveals an apparent stark meridional divide in biogeochemical dynamics associated with the glacial-interglacial cycles of the late Neogene. South of the present-day position of the Antarctic Polar Front biogenic opal is generally much more abundant in sediments during interglacials compared to glacials. To the north, an anti-phased relationship is observed, with maximum opal abundance instead occurring during glacials. This antagonistic response of sedimentary properties is an important model validation target for testing hypotheses of glacial-interglacial change, particularly with respect to understanding the causes of the variability in atmospheric CO 2 . Here, I illustrate a time-dependent modelling approach to helping understand past climatic change by means of the generation of synthetic sediment core records. I find a close match between model-predicted and observed down-core changes in sedimentary opal content is achieved when changes in seasonal sea-ice extent is imposed, suggesting that the cryosphere is probably the primary driver of the striking features exhibited by the paleoceanographic record of this region.