Sea Level Modulation of Atlantic Nitrogen Fixation Over Glacial Cycles ...

N₂ fixation in low-latitude surface waters dominates the input of fixed nitrogen (N) to the global ocean, sustaining ocean fertility. In the Caribbean Sea, higher foraminifera-bound (FB-)δ¹⁵N indicates a decline in N₂ fixation during ice ages, but its cause and broader implications are unclear. Here...

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Bibliographic Details
Main Authors: Auderset, Alexandra, Fripat, François, Creel, Roger C., Oesch, Lukas, Studer, Anja S., Repschläger, Janne, Hathorne, Ed, Vonhof, Hubert, Schiebel, Ralf, Gordon, Laura, Lawrence, Kira, Ren, Haojia Abby, Haug, Gerald H., Sigman, Daniel M., Martínez-García, Alfredo
Format: Text
Language:English
Published: ETH Zurich 2024
Subjects:
North Atlantic
Online Access:https://dx.doi.org/10.3929/ethz-b-000690186
http://hdl.handle.net/20.500.11850/690186
Description
Summary:N₂ fixation in low-latitude surface waters dominates the input of fixed nitrogen (N) to the global ocean, sustaining ocean fertility. In the Caribbean Sea, higher foraminifera-bound (FB-)δ¹⁵N indicates a decline in N₂ fixation during ice ages, but its cause and broader implications are unclear. Here, we report three additional Atlantic FB-δ¹⁵N records, from the subtropical North and South Atlantic gyres (MSM58-50 and DSDP Site 516) and the equatorial Atlantic (ODP Site 662). Similar glacial and interglacial δ¹⁵N in the equatorial Atlantic suggests a stable δ¹⁵N for the nitrate below the gyre thermoclines. The North Atlantic record shows a FB-δ¹⁵N rise during the ice ages, resembling a previously published FB-δ¹⁵N record from the South China Sea. The commonality among the FB-δ¹⁵N records is that they resemble sea level-driven variation in regional shelf area, with high FB-δ¹⁵N (inferred reduction in N2 fixation) during periods of low shelf area. The South China Sea shows the largest δ¹⁵N signal, the ... : Paleoceanography and Paleoclimatology, 39 (8) ...

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