A highly productive subarctic Atlantic during the last interglacial and the role of diatoms

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doi: 10.1130/G32454.1
Author(s): Romero, O. E.; Swann, G. E. A.; Hodell, D. A.; Helmke, P.; Rey, D.; Rubio, B.
Author Affiliation(s): Primary:
Universidad de Granada, Instituto Andaluz de Ciencias de la Tierra, Granada, Spain
University of Nottingham, United Kingdom
University of Cambridge, United Kingdom
Federal Institute of Hydrology, Germany
Universidad de Vigo, Spain
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 39(11), p.1015-1018. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2011301. 27 refs.; sketch map
Summary: The Last Interglacial (LIG), corresponding to Marine Isotope Stage (MIS) 5e, provides a reference of interglacial climate variability in the absence of anthropogenic forcing. Using an expanded section of the LIG gained at Integrated Ocean Drilling Program Site U1304 in the Subarctic Atlantic, we demonstrate that the early MIS 5e was marked by oceanographic conditions conducive for high diatom production and accumulation. The appearance of diatom-dominated laminated oozes ∼3 k.y. after the beginning of MIS 5e at ca. 125 ka coincides with a shift to higher δ30Sidiat values together with the dominance of Thalassiothrix longissima, indicative of increased nutrient availability and silicic acid utilization in surface waters. Though the Subarctic Front provided the physical conditions for high diatom production and deposition, these processes alone are insufficient to explain the high rates of siliceous productivity and the formation of diatomaceous sediments. Instead, the additional presence of an increased nutrient pool provided by Subantarctic Mode Water played the decisive role in initiating and sustaining diatom production. The high diatom productivity and the occurrence of diatomaceous sediments in the late Quaternary challenge the current hypothesis of a silica-depleted North Atlantic during the LIG.
Year of Publication: 2011
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Algae; Atlantic Ocean; Bioclastic sedimentation; Cenozoic; Clastic sediments; Climate change; Diatoms; Expedition 303; Expeditions 303/306; IODP Site U1304; Integrated Ocean Drilling Program; Interglacial environment; MIS 5e; Marine sediments; Microfossils; North Atlantic; Northeast Atlantic; Nutrients; Ocean circulation; Ooze; Paleo-oceanography; Paleoclimatology; Paleoecology; Plantae; Productivity; Quaternary; Sedimentation; Sediments; Subantarctic Mode Water; Subarctic regions; Upper Quaternary
Coordinates: N530300 N530300 W0333200 W0333200
Record ID: 2012007667
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States, Reference includes data supplied by the Geological Society of America