Transient hydrodynamic effects influence organic carbon signatures in marine sediments

Magill, Clayton R. and Ausín, Blanca and Wenk, Pascal and McIntyre, Cameron and Skinner, Luke and Martínez-García, Alfredo and Hodell, David A. and Haug, Gerald H. and Kenney, William and Eglinton, Timothy I. (2018) Transient hydrodynamic effects influence organic carbon signatures in marine sediments. Nature Communications, 9 (1). ISSN 2041-1723 DOI

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Ocean dynamics served an important role during past dramatic climate changes via impacts on deep-ocean carbon storage. Such changes are recorded in sedimentary proxies of hydrographic change on continental margins, which lie at the ocean–atmosphere–earth interface. However, interpretations of these records are challenging, given complex interplays among processes delivering particulate material to and from ocean margins. Here we report radiocarbon (14C) signatures measured for organic carbon in differing grain-size sediment fractions and foraminifera in a sediment core retrieved from the southwest Iberian margin, spanning the last ~25,000 yr. Variable differences of 0–5000 yr in radiocarbon age are apparent between organic carbon in differing grain-sizes and foraminifera of the same sediment layer. The magnitude of 14C differences co-varies with key paleoceanographic indices (e.g., proximal bottom-current density gradients), which we interpret as evidence of Atlantic–Mediterranean seawater exchange influencing grain-size specific carbon accumulation and translocation. These findings underscore an important link between regional hydrodynamics and interpretations of down-core sedimentary proxies.

Item Type: Article
Uncontrolled Keywords: 2018AREP; IA74
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
07 - Gold Open Access
Journal or Publication Title: Nature Communications
Volume: 9
Identification Number:
Depositing User: Sarah Humbert
Date Deposited: 11 Apr 2019 21:00
Last Modified: 11 Apr 2019 21:00

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