Millennial-scale environmental controls on cold-water corals in the South Atlantic - a case study from the Argentine margin

• Main Authors: Dierk Hebbeln, Rodrigo da Costa Portilho Ramos
• Format: Lecture
• Language: unknown
• Published: Zenodo 2021
• Subjects: Antarc*; Antarctic
• Online Access: https://doi.org/10.5281/zenodo.5572616

Along the northern Argentine margin numerous cold-water coral mounds have been found. Little is known about the present distribution of Bathelia candida , the major framework-forming coral in this region. However, based on the analysis of five sediment cores taken from coral mounds between 990 m and 1,300 m, some information exists about their past development. Coral age datings with the Uranium/Thorium methods reveal three major coral growth or mound aggradation phases: 17-15 kyr BP, 14-12 kyr BP, and 11-8 kyr BP, which are linked to changes in the Atlantic Meridional Overturning Circulation (AMOC) and in the strength of the Antarctic Intermediate Water (AAIW). Interestingly, in water depths >1,150 m coral growth was restricted to the 17-15 kyr period during the AMOC breakdown. After that, corals only returned to the Argentine margin to waters shallower than 1,150 m. Still, a puzzling question remains to why the corals did not return after ~6.5 kyr BP, when the AAIW got back to normal strength.