By regulating the amount of water exchange at the Indian-Atlantic Ocean Gateway, or so-called Agulhas Leakage, the meridional variability of the Subtropical Front (STF) in the Southern Hemisphere, linked to expansions or contractions of the Southern Ocean, may have played a significant role in global ocean circulation.
Here, we present new data on primary productivity (chlorins and alkenones) and upper water column temperature (urn:x-wiley:25724517:media:palo21061:palo21061-math-0001 and urn:x-wiley:25724517:media:palo21061:palo21061-math-0002) from marine sediments at IODP Site U1475 on the Agulhas Plateau, close to the In order to analyze indicated changes in the upper oceanic conditions at the mid-Pleistocene transition, we employ these multiproxy time-series records from 1.4 to 0.3 Ma (MPT, ca. 1.2–0.8 Ma).
Our reconstructions in conjunction with earlier proof of the species' migrations of the STF throughout the past 350 ka, the STF may have been farther south from the Agulhas Plateau during the mid-Pleistocene Interim State (MPIS, MIS 23–12), and it may have reached its northernmost position during MIS 34–24 and MIS 10 in the southwest Indian Ocean.
Only the most severe northward migrations of the STF are thought to be related to reduced Agulhas Leakage, according to a comparison with an Agulhas Leakage model obtained from the Cape Basin using Globorotalia menardii.
We believe that the patterns seen during the MPIS may be caused by previously modelled changing westerly winds since STF migrations do not seem to affect Agulhas Leakage variability. In addition to bringing up shifting westerly winds, a separation between STF migrations and Agulhas Leakage may also assist explain fluctuations in CO2 ventilation witnessed throughout the MPIS.
Learn more about STF here:
brainly.com/question/24297407
#SPJ4
