Concentrations, ratios, and sinking fluxes of major bioelements at Ocean Station Papa
Roca Martí, Montserrat (Dalhousie University)
Benitez-Nelson, Claudia (University of South Carolina)
Umhau, Blaire P. (University of South Carolina)
Wyatt, Abigale M. (Princeton University)
Clevenger, Samantha J. (Massachusetts Institute of Technology)
Pike, Steven (Woods Hole Oceanographic Institution)
Horner, Tristan J. (Woods Hole Oceanographic Institution)
Estapa, Margaret L. (University of Maine)
Resplandy, Laure (Princeton University)
Buesseler, Ken (Woods Hole Oceanographic Institution)

Data:	2021
Resum:	Fluxes of major bioelements associated with sinking particles were quantified in late summer 2018 as part of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign near Ocean Station Papa in the subarctic northeast Pacific. The thorium-234 method was used in conjunction with size-fractionated (1-5, 5-51, and >51 mm) concentrations of particulate nitrogen (PN), total particulate phosphorus (TPP), biogenic silica (bSi), and particulate inorganic carbon (PIC) collected using large volume filtration via in situ pumps. We build upon recent work quantifying POC fluxes during EXPORTS. Similar remineralization length scales were observed for both POC and PN across all particle size classes from depths of 50-500 m. Unlike bSi and PIC, the soft tissue-associated POC, PN, and TPP fluxes strongly attenuated from 50 m to the base of the euphotic zone (approximately 120 m). Cruise-average thorium-234-derived fluxes (mmol m-2 d-1) at 120 m were 1. 7 + 0. 6 for POC, 0. 22 + 0. 07 for PN, 0. 019 + 0. 007 for TPP, 0. 69 + 0. 26 for bSi, and 0. 055 + 0. 022 for PIC. These bioelement fluxes were similar to previous observations at this site, with the exception of PIC, which was 1 to 2 orders of magnitude lower. Transfer efficiencies within the upper twilight zone (flux 220 m/flux 120 m) were highest for PIC (84%) and bSi (79%), followed by POC (61%), PN (58%), and TPP (49%). These differences indicate preferential remineralization of TPP relative to POC or PN and larger losses of soft tissue relative to biominerals in sinking particles below the euphotic zone. Comprehensive characterization of the particulate bioelement fluxes obtained here will support future efforts linking phytoplankton community composition and food-web dynamics to the composition, magnitude, and attenuation of material that sinks to deeper waters.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Bioelements ; Biological pump ; EXPORTS ; Particulate fluxes ; Size-fractionated particles ; Transfer efficiency
Publicat a:	Elementa (Washington DC), Vol. 9, Num. 1 (June 2021) , art. 00166, ISSN 2325-1026

DOI: 10.1525/elementa.2020.00166

23 p, 1.8 MB

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