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New insights into processes controlling the δ30Si of sinking diatoms: a seasonally resolved box model approach
Citation
Closset, I and Cardinal, D and Trull, TW and Fripiat, F, New insights into processes controlling the δ30Si of sinking diatoms: a seasonally resolved box model approach, Global Biogeochemical Cycles, 33, (8) pp. 957-970. ISSN 0886-6236 (2019) [Refereed Article]
Copyright Statement
Copyright 2019 American Geophysical Union
Abstract
In the Southern Ocean, the silicon (Si) biogeochemical cycle is dominated by processes such as the supply of Si into the surface waters, Si uptake into diatom frustules, and their subsequent dissolution and export. Due to the incomplete assimilation of the silicic acid pool (DSi) and isotopic fractionation during silicification, the Si isotopic composition (δ30Si) of biogenic silica (BSi) is closely linked to the degree of Si utilization in the mixed layer (ML). In this study, we combined modelling approaches and seasonal sediment trap records of δ30Si of exported BSi to investigate the magnitude, timing, and isotopic composition of the flux of siliceous particles transferred from the surface to the deep ocean. We implemented a box model to describe the temporal evolution of DSi and BSi concentrations and δ30Si in the ML and at depth. The model allows us to quantify fluxes of Si in and out of the ML associated with export, dissolution, and mixing. It highlights that the time‐integrated δ30Si of exported BSi measured in the sediments reflects the extent of DSi consumption at the time when net BSi production and diatom accumulation are maximal in the ML and confirms that the δ30Si of diatoms is a reliable proxy for past Si utilization.
Item Details
Item Type: | Refereed Article |
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Keywords: | silicon isotopes, Southern Ocean, model, silicon cycle, diatoms, export production |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Chemical oceanography |
Objective Division: | Environmental Management |
Objective Group: | Management of Antarctic and Southern Ocean environments |
Objective Field: | Antarctic and Southern Ocean oceanic processes |
UTAS Author: | Trull, TW (Professor Thomas Trull) |
ID Code: | 139513 |
Year Published: | 2019 |
Web of Science® Times Cited: | 2 |
Deposited By: | CRC-Antarctic Climate & Ecosystems |
Deposited On: | 2020-06-18 |
Last Modified: | 2020-07-22 |
Downloads: | 0 |
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