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| DOI | 10.5194/CP-18-147-2022 | ||||
| Año | 2022 | ||||
| Tipo | artículo de investigación |
Citas Totales
Autores Afiliación Chile
Instituciones Chile
% Participación
Internacional
Autores
Afiliación Extranjera
Instituciones
Extranjeras
Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic southeastern Pacific is poorly documented, and its connection to Fe fertilization, potentially related to Patagonian Ice Sheet dynamics, is unknown. We report biological productivity changes over the past 400 kyr, based on a combination of Th-230(xs)-normalized and stratigraphy-based mass accumulation rates of biogenic barium, organic carbon, biogenic opal and calcium carbonate as indicators of paleo-export production in a sediment core upstream of the Drake Passage (57.5 degrees S, 70.3 degrees W). In addition, we use fluxes of iron and lithogenic material as proxies for terrigenous input, and thus potential micronutrient supply. Stratigraphy-based mass accumulation rates are strongly influenced by bottom-current dynamics, which result in variable sediment focussing or winnowing at our site. Carbonate is virtually absent in the core, except during peak interglacial intervals of the Holocene, and Marine Isotope Stages (MIS) 5 and 11, likely caused by transient decreases in carbonate dissolution. All other proxies suggest that export production increased during most glacial periods, coinciding with high iron fluxes. Such augmented glacial iron fluxes at the core site were most likely derived from glaciogenic input from the Patagonian Ice Sheet promoting the growth of phytoplankton. Additionally, glacial export production peaks are also consistent with northward shifts of the Subantarctic and Polar Fronts, which positioned our site south of the Subantarctic Front and closer to silicic acid-rich waters of the Polar Frontal Zone. However, glacial export production near the Drake Passage was lower than in the Atlantic and Indian sectors of the Southern Ocean, which may relate to complete consumption of silicic acid in the study area. Our results underline the importance of micro-nutrient fertilization through lateral terrigenous input from South America rather than eolian transport and exemplify the role of frontal shifts and nutrient limitation for past productivity changes in the Pacific entrance to the Drake Passage.
| Ord. | Autor | Género | Institución - País |
|---|---|---|---|
| 1 | Toyos, Maria H. | Mujer |
Universidad de Concepción - Chile
Universidad Austral de Chile - Chile Helmholtz Zentrum Polar & Meeresforsch - Alemania Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Alemania |
| 2 | Capelli, Cristian | Hombre |
Columbia Univ - Estados Unidos
Lamont-Doherty Earth Observatory - Estados Unidos Columbia University - Estados Unidos |
| 3 | Arz, Helge W. | Hombre |
Leibniz Inst Ostseeforsch Warnemunde IOW - Alemania
The Leibniz Institute for Baltic Sea Research - Alemania |
| 4 | Lembke-Jene, Lester | Hombre |
Helmholtz Zentrum Polar & Meeresforsch - Alemania
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Alemania |
| 5 | LANGE-MAHN, CARINA BEATRIZ | Mujer |
Universidad Austral de Chile - Chile
Universidad de Concepción - Chile Scripps Inst Oceanog - Estados Unidos Scripps Institution of Oceanography - Estados Unidos |
| 6 | Kuhn, Gerhard | Hombre |
Helmholtz Zentrum Polar & Meeresforsch - Alemania
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Alemania |
| 7 | Lamy, Frank | Hombre |
Helmholtz Zentrum Polar & Meeresforsch - Alemania
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Alemania |
| Fuente |
|---|
| scholarship CONICYT-PCHA/Doctorado Nacional |
| Red Clima Red |
| Alfred Wegener Institute Helmholtz Centre fur Polar- und Meeresforschung (PACES-II grant) |
| Doctorado MaReA |
| Chilean oceanographic center COPAS Sur-Austral |
| Postgraduate Office of Universidad de Concepcion |
| Chilean oceanographic center FONDAP-IDEAL |
| Alfred Wegener Institute Helmholtz Centre fur Polar- und Meeresforschung (Changing Earth-Sustaining our Future grant) |
| Agradecimiento |
|---|
| We acknowledge the comments and suggestions by Giuseppe Cortese and Louisa Bradtmiller, which helped us to improve the revised version of this paper. We thank the captain, crew and scientific party of R/V Polarstern for a successful PS97 cruise. We acknowledge Alejandro avila for technical support at the Paleoceanography lab of Universidad de Concepcion; Roseanne Schwartz, Martin Fleisher and Jordan Abell for assistance at Lamont-Doherty Earth Observatory; and Susanne Wiebe, Rita Frohlking and Valea Schumacher for technical support at AWI. |
| We acknowledge the comments and suggestions by Giuseppe Cortese and Louisa Bradtmiller, which helped us to improve the revised version of this paper. We thank the captain, crew and scientific party of R/V Polarstern for a successful<?pagebreak page162?> PS97 cruise. We acknowledge Alejandro avila for technical support at the Paleoceanography lab of Universidad de Concepcion; Roseanne Schwartz, Martin Fleisher and Jordan Abell for assistance at Lamont-Doherty Earth Observatory; and Susanne Wiebe, Rita Frohlking and Valea Schumacher for technical support at AWI. |