Dominance of benthic flux of REEs on continental shelves: implications for oceanic budgets


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Date

2022

Publication Type

Journal Article

ETH Bibliography

yes

Citations

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Data

Abstract

Rare earth elements (REEs) are powerful tools to track oceanic biogeochemical processes. However, our understanding of REE sources is incomplete, leading to controversial interpretations regarding their oceanic cycling. Continental margin sediments are often assumed to be a major source, but the sediment pore water data required to understand the processes controlling that potential source are scarce. Here, we measure and compile pore water and estuarine REE data from the Changjiang (Yangtze) estuary–East China Sea shelf. We show that release of REEs, from shallow pore water to overlying seawater, is coupled to Mn reduction. In contrast, REEs are removed in deep pore water, perhaps via formation of an authigenic REE-bearing phase. This sedimentary source can potentially explain REE addition in the estuary at mid-high salinity. Our calculations suggest that the benthic flux is the largest Nd source (∼40 %) on the East China Sea shelf. Globally, however, despite a higher benthic Nd flux on the advection-dominated shelf, the much more extensive deep ocean still dominates the total area-integrated benthic flux. Our results call for a more extensive investigation of the magnitude of the benthic flux of REEs to the oceans.

Publication status

published

Editor

Book title

Volume

22

Pages / Article No.

26 - 30

Publisher

European Association of Geochemistry

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Boundary exchange; Sediment-water interface; Benthic process; East China Sea Shelf; Rare earth element

Organisational unit

03956 - Vance, Derek / Vance, Derek check_circle

Notes

Funding

19-2 FEL-32 - The critical role of sedimentary trace element fluxes in ocean biogeochemistry (ETHZ)
20-1 FEL-24 - ETH Zurich Postdoctoral Fellowship Application 20-1 FEL-24 «Role of continental margin sediments in the oceanic mass balance of beryllium» (ETHZ)

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