In chapters 1-‐3 of this thesis a general introduction to the topic, the data and analysis tools used is provided. A second part of this thesis (chapters 4-‐8) includes manuscripts that are published in, submitted to or in preparation for international peer-‐reviewed journals. Finally, a third part (chapters 9) summarizes the main conclusions of the previous chapters in a synthesis this thesis are available in the PANGAEA database (http://www.pangaea.de).
Chapter 4: Tracking the equatorial front in the eastern equatorial Pacific Ocean by the isotopic and faunal composition of planktonic foraminifera
Daniel Rincón-‐Martínez, Silke Steph, Frank Lamy, Alan Mix and Ralf Tiedemann variations in temperature, salinity, and geographically-‐inconsistent seasonal upwelling along the study's general north-‐south transect. Standard methods are used for predicting the δ18O of calcite, and the oxygen isotopic difference between Globigerinoides ruber and Globorotalia tumida (Δδ18OG.tumida-‐G.ruber) and between Pulleniatina oliquiloculata and G. tumida (Δδ18OG.tumida-‐
P.obliquiloculata) are useful paleoceanographic tools for reconstructing the latitudinal position of the eastern Pacific Equatorial Front in an area delimited by the Cocos and Carnegie ridges.
CHAPTER 1
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In this chapter Daniel Rincón-‐Martínez contributed to develop research strategy, performed laboratory work for the preparation and analysis of micropaleontological samples by Mass Spectrometer, processed and interpreted data, and produced figures. Silke Steph, Frank Lamy and Ralf Tiedemann developed research strategy. Alan Mix performed fieldtrip and provided sample set. Daniel Rincón-‐Martínez and Silke Steph wrote the paper. All co-‐authors provided
This study reconstructs ocean surface conditions in the equatorial eastern Pacific Ocean over the past half-‐million years. From a suite of marine sediment based proxies such as XRF scanning, alkenone-‐based SST, biomarkers and planktonic foraminifera oxygen isotopes it is inferred that precipitation along the coast of Ecuador has varied across glacial–interglacial cycles, with more aridity associated with glacial conditions. The lowest amounts of terrestrial run-‐off during glacial periods are accompanied with strong latitudinal and meridional SST Tiedemann developed research strategy, and produced age model. Sergio Contreras assisted with laboratory work for the preparation and analysis of terrigenous biomarkers (taraxerol).
Thomas Blanz facilitated his laboratory at Christian-‐Albrechts-‐Universitaet zu Kiel and contributed with alkenone-‐based SST data and interpretation. Andreas Mackensen facilitated his laboratory at AWI and contributed with oxygen isotopes data and interpretation. Guillaume Leduc and Edouard Bard contributed with SST data and interpretation. Daniel Rincón-‐Martínez wrote the paper with major contributions from Frank Lamy, Ralf Tiedemann, Sergio Contreras and Guillaume Leduc. All co-‐authors provided editorial comments.
resolution records of molecular marine and terrestrial biomarkers preserved in Peruvian shelf sediments it is suggested that warmer and wetter conditions along the coast occurred during the last Interglacial, when global temperatures were comparable or even higher than today.
The authors attribute this to a prolonged El Niño-‐like response of the tropical Pacific during this time interval. Globally, however, the intertropical convergence zone is thought to shift
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Daniel Rincón-‐Martínez contributed on the analysis of X-‐Ray Fluorescence (XRF) scanning data and built the age model from sedimentary data and benthic foraminifera oxygen isotopes.
Sergio Contreras wrote the paper with contributions from Daniel Rincón-‐Martínez and Carina Lange. All co-‐authors provided editorial comments.
Chapter 7: Late Quaternary glacial-‐interglacial climate variability of western South America inferred from eolian dust as preserved in marine sediments
Cornelia Saukel, Frank Lamy, Jerry McManus, Daniel Rincón-‐Martinez, Jan-‐Berend W. Stuut, Gisela Winckler, and Ralf Tiedemann scanning and estimation of elemental concentrations by ICP-‐OES. Additionally Cornelia Saukel processed and interpreted data, and produced figures. Frank Lamy and Ralf Tiedemann developed research strategy, and produced age model. Jan-‐Berend W. Stuut facilitated his laboratory at MARUM and contributed with grain-‐size data and interpretation. Gisela Winckler facilitated his laboratory at LDEO and contributed with thorium isotopes data and interpretation of dust mass fluxes. Cornelia Saukel wrote the manuscript with contributions from Frank Lamy, Jerry McManus, and Gisela Winckler. All co-‐authors provided editorial comments.
Chapter 8: Investigating the biogeochemical cycles and primary productivity changes in the eastern equatorial Pacific during the Pliocene-‐Pleistocene climate transition
Johan Etorneau, Daniel Rincón-‐Martinez, Philippe Martinez, Frank Lamy, Thomas Blanz, Cornelia Saukel, Ralf Tiedemann and Ralph Schneider
First draft of manuscript in preparation for submission to Paleoceanography
Based on a multiproxy approach, this study examines different factors capable to control the overall primary productivity of the last 3 Ma in the Eastern Equatorial Pacific, a high-‐nutrient, CHAPTER 1
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low-‐chlorophyll region of the ocean. The results show that increases in phytoplankton biomass since the Pliocene in the study area responded primarily to the nutrients distribution into the photic zone, and particularly to iron (Fe) fertilization. We found that nitrate -‐ an essential nutrient for biological productivity -‐ was likely sufficiently supplied at surface waters and has supported not limited, productivity since 3 Ma. In contrast, Fe inputs, currently limited in the modern Eastern Equatorial Pacific, have probably served as fertilizer to trigger the most productive period between 2.4 and 1.6 Ma. This was synchronous to a more vigorous cold tongue associated to a strong supply of nutrient-‐rich cold waters upwelled in the EEP shifting northward the EF.
In this chapter Johan Etorneau, Philippe Martinez and Daniel Rincón-‐Martínez contributed to develop research strategy. Johan Etorneau, Daniel Rincón-‐Martínez and Cornelia Saukel, performed laboratory work concerning the determination of total organic carbon (TOC), the determination of the concentration of biogenic silica and alkenones, X-‐Ray Fluorescence (XRF) scanning and estimation of elemental concentrations by ICP-‐OES. Additionally Johan Etorneau processed and interpreted data, and produced figures. Ralf Tiedemann, Frank Lamy and Ralph Schneider developed research strategy. Philippe Martinez facilitated his laboratory at EPOC Université Bordeaux 1 and contributed with nitrogen isotope data and interpretation. Thomas Blanz facilitated his laboratory at Christian-‐Albrechts-‐Universitaet zu Kiel and contributed with alkenone-‐based SST data and interpretation. Johan Etorneau wrote the paper with contributions from Daniel Rincón-‐Martinez, Philippe Martinez and Frank Lamy. All co-‐authors provided editorial comments.
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CHAPTER 2
STUDY AREA: THE EASTERN TROPICAL AND SUBTROPICAL PACIFIC
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2.1. The Coupled Ocean-‐Land-‐Atmosphere System in the Eastern Tropical Pacific descending branch of the Hadley-‐Walker circulation. The large static stabilities associated with cold SSTs and atmospheric subsidence result in extensive marine stratus cloud deck. Although these clouds reflect much of the incoming solar radiation, they interfere very little with the loss of energy via thermal radiation, resulting in less radiative heating of the cold water region than in the warm water area (Ma et al., 1996). The overall effect of the distribution of evaporation and radiative heating and cooling is thus reinforcement of the preexisting thermal contrast illustrated in Figure 2.2.