Coccolith-calcite Sr/Ca as a proxy for transient export production related to Saharan dust deposition in the tropical North Atlantic
Guerreiro, Catarina V. (University of Lisbon)
Cavaleiro, C. (Portuguese Institute for Sea and Atmosphere)
Stuut, Jan-Berend W. (Vrije Universiteit)
Ziveri, Patrizia (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)

Data:	2024
Resum:	Atmospheric dust deposition can modulate the earth's climate and atmospheric CO2 through fertilising the ocean (nutrient source) and by accelerating the biological carbon pump through fuelling the ballasting process. To distinguish the biogeochemical effects of Saharan dust with respect to fertilization and ballasting, and to gain a broader perspective on the coccolith calcite Sr/Ca in relation to the drivers of coccolith export production, we determined the coccolith-Sr/Ca from a one-year (2012-2013) time-series sediment trap record in the western tropical North Atlantic (M4-49°N/12°W). High Sr/Ca were linked to enhanced export production in the upper part of the photic zone, most notably under windier, dry, and dustier conditions during spring. Attenuated Sr/Ca in the autumn probably reflect a combination of lower Sr-incorporation by dominant but small-size placolith-bearing species and the presence of "aged" coccoliths rapidly scavenged during a highly productive and usually fast export event, likely added by (wet) dust ballasting. Higher Sr/Ca observed in the large coccolith size fractions support the existing notion that larger-sized coccolithophores incorporate more Sr during calcification under the same environmental conditions. The presence of the abnormally Sr-rich species Scyphosphaera apsteinii is also shown in the separated large fraction of our Sr/Ca seasonal data.
Ajuts:	European Commission 311152 European Commission 600411 European Commission 796802 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1588
Nota:	Unidad de excelencia María de Maeztu CEX2019-000940-M
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
Publicat a:	Scientific reports, Vol. 14 (February 2024) , art. 4295, ISSN 2045-2322

DOI: 10.1038/s41598-024-54001-3
PMID: 38383618

12 p, 2.2 MB

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