Pleistocene variations in dust input and marine productivity in the northern Benguela Current: Evidence of evolution of global glacial–interglacial cycles

Jahn, Britta; Donner, Barbara; Müller, Peter; Röhl, Ursula; Schneider, Ralph R; Wefer, Gerold

doi:10.1016/s0031-0182(03)00264-5

Cited by 48 publications

(43 citation statements)

References 38 publications

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“…Wind intensity determines the degree of transport of cold upwelled water in filaments over the Walvis Ridge (West et al, 2004), with stronger upwelling occurring during precession maxima resulting from stronger SE trade winds. Trade wind modulated productivity in this region of the South Atlantic has been observed for the Quaternary (Schneider et al, 1996;Jahn et al, 2003). Furthermore, extant coccolithophore assemblages in the Southwestern African margin, similar to other upwelling regions, are largely governed by changes in upwelling intensity (Boeckel and Baumann, 2004;Ziveri et al, 1995;Ziveri and Thunell, 2000).…”

Section: Mechanisms For Stimulating Productivity and Relationships Tomentioning

confidence: 75%

Productivity response of calcareous nannoplankton to Eocene Thermal Maximum 2 (ETM2)

et al. 2012

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Abstract. The Early Eocene Thermal Maximum 2 (ETM2) at ∼53.7 Ma is one of multiple hyperthermal events that followed the Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma). The negative carbon excursion and deep ocean carbonate dissolution which occurred during the event imply that a substantial amount (10 3 Gt) of carbon (C) was added to the ocean-atmosphere system, consequently increasing atmospheric CO 2 (pCO 2 ). This makes the event relevant to the current scenario of anthropogenic CO 2 additions and global change. Resulting changes in ocean stratification and pH, as well as changes in exogenic cycles which supply nutrients to the ocean, may have affected the productivity of marine phytoplankton, especially calcifying phytoplankton. Changes in productivity, in turn, may affect the rate of sequestration of excess CO 2 in the deep ocean and sediments. In order to reconstruct the productivity response by calcareous nannoplankton to ETM2 in the South Atlantic (Site 1265) and North Pacific (Site 1209), we employ the coccolith Sr/Ca productivity proxy with analysis of well-preserved picked monogeneric populations by ion probe supplemented by analysis of various size fractions of nannofossil sediments by ICP-AES. The former technique of measuring Sr/Ca in selected nannofossil populations using the ion probe circumvents possible contamination with secondary calcite. Avoiding such contamination is important for an accurate interpretation of the nannoplankton productivity record, since diagenetic processes can bias the productivity signal, as we demonstrate for Sr/Ca measurements in the fine (<20 µm) and other size fractions obtained from bulk sediments from Site 1265. At this site, the paleoproductivity signal as reconstructed from the Sr/Ca appears to be governed by cyclic changes, possibly orbital forcing, resulting in a 20-30 % variability in Sr/Ca in dominant genera as obtained by ion probe. The ∼13 to 21 % increase in Sr/Ca above the cyclic background conditions as measured by ion probe in dominating genera may result from a slightly elevated productivity during ETM2. This high productivity phase is probably the result of enhanced nutrient supply either from land or from upwelling. The ion probe results show that calcareous nannoplankton productivity was not reduced by environmental conditions accompanying ETM2 at Site 1265, but imply an overall sustained productivity and potentially a small productivity increase during the extreme climatic conditions of ETM2 in this portion of the South Atlantic. However, in the open oceanic setting of Site 1209, a significant decrease in dominant genera Sr/Ca is observed, indicating reduced productivity.

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Section: Mechanisms For Stimulating Productivity and Relationships Tomentioning

confidence: 75%

Productivity response of calcareous nannoplankton to Eocene Thermal Maximum 2 (ETM2)

et al. 2012

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“…The episode of change through Termination V has been referred to as the "Mid-Brunhes Event" (MBE), and the originators of this term (Jansen et al, 1986) also documented evidence for a southward migration of the APF (Ciesielski and Weaver, 1983). The Benguela Current system also rapidly warmed during Termination V to reach a consistently higher interglacial and glacial temperature pattern persisting to the present (Jahn et al, 2003) (Fig. 5c).…”

Section: The "Mid-brunhes Event" (424 Ka) Termination V Southward Rmentioning

confidence: 99%

Migration of the Antarctic Polar Front through the mid-Pleistocene transition: evidence and climatic implications

Kemp

Grigorov

Pearce

et al. 2010

Quaternary Science Reviews

108

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“…Norris and R€ ohl, 1999;Peterson et al, 2000;R€ ohl et al, 2000;Arz et al, 2001;Lamy et al, 2001;Grutzner et al, 2003;Haug et al, 2003;Jahn et al, 2003;Lamy et al, 2004;Tierney et al, 2005;Brown et al, 2007;Donnelly and Woodruff, 2007). Titanium and Fe are commonly attributed to terrigenous inputs in pelagic and hemipelagic sediments and thus have been used as proxies for river runoff and precipitation (Peterson and Haug, 2006).…”

Section: Elemental Analysesmentioning

confidence: 99%

From extreme rainfall to drought: 250 years of annually resolved sediment deposition in Santa Barbara Basin, California

Hendy

Napier

Schimmelmann

2015

Quaternary International

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a b s t r a c tThe Mediterranean climate of southern California is marked by droughts and extreme precipitation events. Here we use elemental variations generated by scanning X-ray fluorescence (XRF) to identify droughts and floods in recently deposited (1755e2008) sediments of Santa Barbara Basin (SBB) from box core SPR0901-04BC. The first principal component (PC1) of the scanning XRF elements has high loadings for elements associated with the lithogenic component of SBB laminae couplets, while the second (PC2) is associated with biogenic components. We interpret PC1 as a proxy for river runoff and PC2 as a proxy for marine productivity. High values of PC1 are associated with El Niño events and positive (warm) phases of the Pacific Decadal Oscillation (PDO), while low values of PC2 are associated with El Niño events and negative (cool) phases of the PDO. Droughts such as the 1934e40, 1949e56, and 1989e91 events coincide with low PC1 values. In addition to distinguishing interannual and decadal variability in the elemental composition of SBB sediments, several historic floods can be recognized including a gray flood layer associated with the 1861e62 flood, and a peak in PC1 associated with the flood following the St. Francis Dam disaster in 1928.

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Pleistocene variations in dust input and marine productivity in the northern Benguela Current: Evidence of evolution of global glacial–interglacial cycles

Cited by 48 publications

References 38 publications

Productivity response of calcareous nannoplankton to Eocene Thermal Maximum 2 (ETM2)

Productivity response of calcareous nannoplankton to Eocene Thermal Maximum 2 (ETM2)

Migration of the Antarctic Polar Front through the mid-Pleistocene transition: evidence and climatic implications

From extreme rainfall to drought: 250 years of annually resolved sediment deposition in Santa Barbara Basin, California

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