Strong glacial-interglacial variability in upper ocean hydrodynamics, biogeochemistry, and productivity in the southern Indian Ocean
Berke, Melissa A.
Cartagena-Sierra, Alejandra
Flores, José Abel
Gruetzner, Jens
Jiménez-Espejo, Francisco
LeVay, Leah J.
Baumann, Karl-Heinz
Romero, Oscar
Saavedra-Pellitero, Mariem
Coenen, Jason J.
Starr, Aidan
Hemming, Sidney R.
Hall, Ian R.
DOI: https://doi.org/10.1038/s43247-021-00148-0
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11058
Berke, Melissa A.; Department of Civil & Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, USA
Cartagena-Sierra, Alejandra; Department of Civil & Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, USA
Flores, José Abel; Departamento de Geología, Universidad de Salamanca, Salamanca, Spain
Gruetzner, Jens; Alfred-Wegener-Institut for Polar and Marine Research, Bremerhaven, Germany
Jiménez-Espejo, Francisco; Research Institute for Marine Resources Utilization (Biogeochemistry Program), JAMSTEC, Yokosuka, Japan
LeVay, Leah J.; International Ocean Discovery Program, Texas A&M University, College Station, USA
Baumann, Karl-Heinz; University of Bremen, Department of Geosciences, Bremen, Germany
Romero, Oscar; MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
Saavedra-Pellitero, Mariem; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
Coenen, Jason J.; Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb, USA
Starr, Aidan; School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
Hemming, Sidney R.; Lamont-Doherty Earth Observatory, Columbia University, Palisades, USA
Hall, Ian R.; School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
Abstract
In the southern Indian Ocean, the position of the subtropical front – the boundary between colder, fresher waters to the south and warmer, saltier waters to the north – has a strong influence on the upper ocean hydrodynamics and biogeochemistry. Here we analyse a sedimentary record from the Agulhas Plateau, located close to the modern position of the subtropical front and use alkenones and coccolith assemblages to reconstruct oceanographic conditions over the past 300,000 years. We identify a strong glacial-interglacial variability in sea surface temperature and productivity associated with subtropical front migration over the Agulhas Plateau, as well as shorter-term high frequency variability aligned with variations in high latitude insolation. Alkenone and coccolith abundances, in combination with diatom and organic carbon records indicate high glacial export productivity. We conclude that the biological pump was more efficient and strengthened during glacial periods, which could partly account for the reported reduction in atmospheric carbon dioxide concentrations.
Migration of the Subtropical Front during glacial and interglacial periods resulted in variability in the strength of the biological pump in the Southern Ocean sector of the Indian Ocean, according to sedimentary records from the Agulhas Plateau.
Subjects
palaeoceanographysouthern Indian Ocean
Agulhas Plateau
upper ocean hydrodynamics
biogeochemistry