Southern-ocean and glaciogenic nutrients control diatom export production on the Chile margin

Chase, Zanna; McManus, James; Mix, Alan C; Muratli, Jesse M

doi:10.1016/j.quascirev.2014.06.015

Cited by 22 publications

(23 citation statements)

References 68 publications

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“…However, Muratli et al (2010b), who reconstructed paleoproductivity over the last ~30 kyrs for ODP 1234, suggested that the rise in TOC after the LGM is probably not the result of increased productivity, but of a lower oxygen availability due to 25 decreased Antarctic Intermediate Water ventilation, and thus increased preservation, since both opal concentrations and opal and organic carbon MARs do not increase simultaneous with TOC concentrations. Chase et al (2014) support this hypothesis based on the Th normalized organic carbon fluxes. Our (unnormalized) MARTOC support these findings since although TOC levels show a steady rise after the LGM, we do not observe this increase in the accumulation of organic carbon, and the MARTOC is higher during the LGM as compared to the Holocene, suggesting higher glacial productivity.…”

Section: Productivitysupporting

confidence: 72%

“…Marine sediments along the coast of Chile and Peru have been thoroughly studied, as it is a key region in the southern hemisphere for studying climate variability related to both atmospheric and oceanographic circulation (e.g., Lamy et al, 1998Lamy et al, , 1999Lamy et al, , 2002Lamy et al, , 2004Hebbeln et al, 2000Hebbeln et al, , 2002Mohtadi & Hebbeln, 2004;Stuut and Lamy, 2004;Heusser et al, 2006;Romero et al, 2006;Mohtadi et al, 2008;Muratli et al, 2010aMuratli et al, , 2010bVerleye & Louwye, 2010;Chase et al, 2014). The main circulation patterns include the Southern Westerly Winds (SWW) and the Antarctic Circumpolar Current (ACC; Fig 1).…”

Section: Study Site 20mentioning

confidence: 99%

See 1 more Smart Citation

A Late Quaternary climate record based on long chain diol proxies from the Chilean margin

Bar¹,

Stolwijk²,

McManus³

et al. 2018

Preprint

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Abstract. The primary focus of this study is to test the applicability of different paleoenvironmental proxies based on long chain diols, i.e., the LDI as proxy for past SST, the Diol Index as indicator of past upwelling conditions and the NDI as quantitative proxy for nitrate and phosphate concentrations in seawater. The proxies were analyzed in marine sediments recovered at ODP Site 1234, located within the Peru-Chile upwelling system, with a ~ 2 kyr resolution, covering the last 150 kyrs, i.e., encompassing several glacial and interglacial periods. We also generated TEXH86 and UK´37 temperature and planktonic δ18O records, as well as TOC and accumulation rates (ARs) of TOC and lipid biomarkers (i.e., C37 alkenones, GDGTs, dinosterol and loliolide) to reconstruct past phytoplankton production. The LDI-derived SST record co-varies with TEXH86- and UK´37-derived SST records as well as with the planktonic δ18O record, implying that the LDI reflects past SST variations at this site. TOC and phytoplankton AR records indicate increased export production during the Last Interglacial (MIS 5), simultaneous with a peak in the abundance of preserved Chaetoceros diatoms, suggesting intensified upwelling during this period. The Diol Index is relatively low during the upwelling period, but peaks before and after this period, suggesting that Proboscia diatoms were more dominant before and after the period of upwelling. The NDI reveals the same variations as the Diol Index suggesting that the input of nitrate and phosphate was minimal during upwelling, which is unrealistic. We suggest that the Diol Index should perhaps be considered as an indicator for Proboscia (multiple species) productivity instead of upwelling per se, whereas the NDI likely reflects Proboscia alata productivity, and might therefore not be suitable as a more general paleonutrient proxy.

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Section: Productivitysupporting

confidence: 72%

Section: Study Site 20mentioning

confidence: 99%

A Late Quaternary climate record based on long chain diol proxies from the Chilean margin

Bar¹,

Stolwijk²,

McManus³

et al. 2018

Preprint

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show abstract

“…Muratli et al (2010) based this finding on the mismatch between the increase of opal and TOC-AR with the TOC concentrations. This hypothesis has been supported by thorium-normalized Corg data from Chase et al (2014), who further suggested that between 36°S to 41°S the increase in coastal productivity during LGM is in agreement with the process invoked to explain increased LGM productivity further north in the HCS, such as a larger supply of macronutrients due to the migration of the ACC and a higher input of micronutrient due to higher continental runoff (Hebbeln et al, 2002;Mohtadi et al, 2004;Romero et al, 2006).…”

Section: Previous Paleoproductivity Reconstructions From the Chilean Margin Focusing On Lgm-holocene Changesmentioning

confidence: 61%

Increased Marine Productivity in the Southern Humboldt Current System During MIS 2–4 and 10–11

Tapia

Nunez-Ricardo

et al. 2021

Paleoceanog and Paleoclimatol

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The Humboldt Current System (HCS) is the world's most productive eastern boundary upwelling system (Montecino & Lange, 2009). It stretches along the west coast of South America, from southern Chile (40°S-45°S) to northern Peru (4°S) (Figure 1a). Historical data show that the HCS's marine productivity changes in response to inter-annual climatic modes, such as the El Niño-Southern Oscillation (Montecino & Lange, 2009). However, our knowledge about the response of the HCS to climate change on longer time scales, especially beyond the last glacial, is still largely fragmentary.Paleoproductivity studies in the southern part of the HCS have so far been confined to the coastal area between 36°S and 41°S, and their findings suggest either lower glacial productivity (

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“…The model is constrained by six high‐resolution paleomagnetic records from globally distributed sites: the Black Sea PSV stacks (data from this study), data from Core JPC‐14, North Atlantic Ocean (Lund et al, 2001, 2005), Site ODP‐1233, Chile Margin, SE Pacific (Lund, Stoner, & Lamy, 2006; Lund et al, 2007), Core MD94‐103, southern Indian Ocean (Mazaud et al, 2002), Core MD98‐2181, western equatorial Pacific Ocean (Lund, Schwartz, et al, 2017), and Core PLC08‐1, Pyramid Lake, USA (Lund, Benson, et al, 2017). New age models were derived for Site ODP‐1233 (Chase et al, 2014) and Core MD94‐103 records (Sicre et al, 2005). From this limited but highly improved data set including only high‐quality records with good age controls, we derived a model with a better temporal resolution and more consistent global variations.…”

Section: Resultsmentioning

confidence: 99%

The Norwegian‐Greenland Sea, the Laschamps, and the Mono Lake Excursions Recorded in a Black Sea Sedimentary Sequence Spanning From 68.9 to 14.5 ka

et al. 2020

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A full‐vector paleomagnetic record, comprising directional data and relative paleointensity (rPI), was derived from 16 sediment cores recovered from the southeastern Black Sea. The obtained data were used to create a stack covering the time window between 68.9 and 14.5 ka. Age models are based on radiocarbon dating and correlations of warming/cooling cycles monitored by high‐resolution X‐ray fluorescence (XRF) elementary ratios and by ice‐rafted debris (IRD) in Black Sea sediments to the sequence of “Dansgaard‐Oeschger” (D‐O) events defined from the Greenland ice core oxygen isotope stratigraphy. The reconstructed prominent lows in paleointensity at about 64.5, 41.2, and 34.5 ka are coeval with the Norwegian‐Greenland Sea, the Laschamps, and the Mono Lake excursions, respectively. For a further analysis, the stacked Black Sea paleomagnetic record was converted into one component being parallel to the direction expected from a geocentric axial dipole (GAD) and two components perpendicular to it (EW, inclined NS), representing definitely only non‐GAD components of the geomagnetic field. Discussions of the field configurations at the Black Sea site are focused on the three excursional events. The Norwegian‐Greenland Sea excursion was dominated by a decaying axial dipole and persisting weak nondipole field, with directional variations still within the range of normal secular variations. The Laschamps excursion comprises two full polarity transitions and a short stable interval of reversed polarity in between. The Mono Lake excursion was mostly dominated by a nondipole field, though with a less pronounced weakening of the axial dipole component.

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Southern-ocean and glaciogenic nutrients control diatom export production on the Chile margin

Cited by 22 publications

References 68 publications

A Late Quaternary climate record based on long chain diol proxies from the Chilean margin

A Late Quaternary climate record based on long chain diol proxies from the Chilean margin

Increased Marine Productivity in the Southern Humboldt Current System During MIS 2–4 and 10–11

The Norwegian‐Greenland Sea, the Laschamps, and the Mono Lake Excursions Recorded in a Black Sea Sedimentary Sequence Spanning From 68.9 to 14.5 ka

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