Sara Marconato, 2022 Winner of a Katharina von Salis Graduate Research Fellowship

I am currently a PhD student at Ben-Gurion University of the Negev, Israel, and the current study is being run in collaboration with the University of Copenhagen, Denmark, the Geological Survey of Israel and the Arava Science Center, Israel.

My PhD project focuses on the paleoecology, biostratigraphy and biometry of Late Cretaceous calcareous nannofossils in the upwelling system of the Levant area. For this time interval, research on calcareous nannofossils in the context of a rich eutrophic zone has rarely been conducted. This region has a deposition of thick successions of organic-rich chalk that continues across the K-Pg boundary and into the early Paleocene. These studies will be a step forward towards understanding the evolution and the community strategies of coccolithophoridae in such an environment, where they supposedly reached a threshold in their trophic preferences. In particular, it will be interesting to document if the global climatic events of the Campanian to Maastrichtian had any influence on the intensity of upwelling in the Levant area.

The Shefela project, whose preliminary results I presented in a poster during INA18 in Avignon, is about to finish and only some final geochemical measurements remain to be performed, in order to detect with more resolution negative shifts related to climatic events. The main preliminary conclusions from this project are that calcareous nannofossil assemblages are abundant and with a medium species richness in the very eutrophic conditions of the upwelling zone. The assemblages reacted to the main climatic events of the Campanian-Maastrichtian, although the paleoecological conditions were not oligotrophic. This is very important because it confirms the broad ecological tolerance of coccolithophorids and we hope, by the end of my PhD, to be able to fully explain the conditions of life of calcareous nannofossils assemblages in eutrophic environment during Late Cretaceous.

Expenses were used on the SEM to identify a very abundant particular species found in optical microscope and there is the willingness to spend $550 for Mesozoic INASSET Summer School in Parma. There is also the willingness to organize a trip to Copenhagen next year and I started to talk with my Lab Manager for a new hood.

Felipe Vallejo, 2022 Winner of a Katharina von Salis Graduate Research Fellowship

I am a PhD student at the Universidad de Salamanca in Spain and the Instituto de Investigaciones en Estratigrafía (IIES) in Colombia. I have been using calcareous nannofossils to build a chronostratigraphic framework for Pacific and Caribbean onshore deposits from Colombia in order to better understand the evolution of the eastern tropical Pacific Ocean and the Caribbean Sea.

Two of the world's largest oceans, the Pacific and Atlantic Oceans, were connected by a tropical seaway known as the Central American Seaway (CAS). During the Neogene, the CAS was characterized by several gateways that crossed the Panamá volcanic arc, which was colliding with the northern Andes of South America. As part of my PhD, I am using the biostratigraphic resolution of calcareous nannofossils and combining this with other stratigraphic proxies to understand how and when the closure of the CAS in the collision zone occurred. We have documented that the CAS was already vanishing in the early to middle Miocene and that it entirely closed during the middle to late Miocene in this region. Our data help us to understand that the CAS closed diachronously, and that deep-ocean circulation was already affected in the early-middle Miocene.

The funds granted to me were used as a scholarship to cover my living expenses during my visit with my supervisor, Dr. José Abel Flores, and for the preparation and analysis of samples for calcareous nannofossils. Although I am currently a PhD student at the University of Salamanca, my research requires me to spend a significant amount of time in Colombia. As a result, I needed to have in-person sessions with my supervisor to discuss specific taxonomic questions related to the determination of calcareous nannofossils.

During my visit, Dr. Flores and I were able to address these questions, and I am currently in the process of preparing and analyzing additional samples. Our goal is to increase the biostratigraphic resolution of the, already sampled, stratigraphic section from the northern part of my study area. The results from these analyses will enable us to complete the age model for a manuscript that is required for my PhD graduation.

Janina Falkenberg, 2021 Winner of a Katharina von Salis Graduate Research Fellowship

I am currently a PhD student at the Ruhr-University Bochum (Germany) and working on the use of calcareous nannofossils in archaeology, a field in which they are still poorly known and underused. My research focuses on historic lime-based mortars. These mortars are produced by burning naturally occurring limestones at > 800°C. Due to these high temperatures nannofossils are not expected to be present in the lime binders of mortars. They have, however, been detected in historic mortars.

The main goal of my research project is to establish the use of calcareous nannofossils as a tool for provenance analyses and archaeothermometry of lime-based mortars. By studying different historic buildings, I have already documented that nannofossils are preserved in historic mortars and can be used for provenance analysis. I further want to gain experimental data on how calcareous nannofossils react to increasing temperatures during the burning process. These data will then be applied to historic mortars to reconstruct the burning temperature reached during quicklime production. My studies will thus contribute to the understanding of historic mortar production.

Boris Karatsolis, 2021 Winner of a Katharina von Salis Graduate Research Fellowship

I have been studying nannoplankton and nannofossil assemblages since my bachelor years, moving across host universities that are roughly located in a south to north transect (University of Athens/Milano-Bicocca/Bremen). Loyal to this trip towards higher latitudes, I am currently a PhD student at the Department of Earth Sciences at Uppsala University, Sweden.

Disregarding my “host university transit”, my research has been mainly focused on low-latitude areas and, specifically for my PhD, the NW Australian shelf (IODP Expedition 356). My main scientific interest is understanding late Neogene coccolithophore paleoproductivity and species distribution changes in light of their potential paleoclimatic drivers. Additionally, I am interested in decoupling regional signals of change in coccolith assemblages from global evolutionary patterns. Finally, I aim to investigate an interesting period of elevated paleoproductivity, the late Miocene- early Pliocene biogenic bloom, and compare differences in expression and intensity of this event between lower (e.g the Tropics) and higher latitudes (e.g. north Atlantic-recently drilled IODP Expedition 395 Sites).

Lucia Rivas, 2020 Winner of a Katharina von Salis Graduate Research Fellowship

I am currently a PhD student at Universidad Nacional de La Plata and working at YPF-Tecnología, Argentina. My PhD project is focused on the latest Neogene to Recent calcareous nannofossil record on the Argentina Continental Margin (ACM). My research focuses on identifying oceanographic factors that control calcareous nannofossil distribution and reconstructing paleoceanographic conditions in the area. The study sites are located along a north-south transect on the ACM, one of the largest continental margins on the Earth and a crucial region where the Antarctic and Equator water-masses interact. Therefore, the ACM geologic record is a unique archive that can be used to understand the paleoceanographic and climatic evolution in the region and for the rest of the Southern Hemisphere.

The main goal of my research project is to identify and compare geographical distribution patterns of coccolith assemblages and evaluate their relationship with environmental variables on the ACM. These results will be used in my second goal, which is to analyze Neogene to Quaternary calcareous nannofossil assemblages of five gravity cores from the ACM. This information will be correlated with sedimentological and geochemical data (intensive measurements of TOC and stable isotopes in foraminiferal tests, ¹³C and ¹⁸O) in a multiproxy approach that will be used to document paleoenvironmental changes on the ACM through time.

Odysseus Archontikis, 2020 Winner of a Katharina von Salis Graduate Research Fellowship

I am fascinated by the bidirectional interplay between plankton (palaeo)biology and the Earth's climate. My current PhD research at the University of Oxford centres on investigation into the mechanisms of evolutionary adaptation in the marine realm across spatial and temporal scales.

At present, I aim to understand the recent evolutionary history of coccolithophores and shed light on the macro- and micro-evolutionary processes driving plankton speciation in the open oceans. Evolutionary patterns can be comprehensively documented in the geological record in extraordinary detail, but have also been accrued to some extent in the physiology and genomes of the modern organisms. Using a range of palaeontological and biogeochemical techniques, my focus is to determine the interaction between the morphological signals of coccoliths (microscopic fossil remains of coccolithophores) within deep oceanic sediments and of genetic variation in extant organisms to understand the genetic flow underpinning speciation events.

Mica Chaumeil Rodriquez, 2019 Winner of a Katharina von Salis Graduate Research Fellowship

I am a PhD student in a joint PhD program between the Universidad Nacional de La Plata (Argentina) and the Université Claude Bernard Lyon 1 (France). My research project is focused on Early-Middle Jurassic calcareous nannofossil assemblages from the Los Molles Formation, Neuquén Basin, Argentina. The associations present in this locality constitute the only record of this group in the Southwestern Pacific Ocean for the Early to Middle Jurassic. Their study is key to unveiling its early evolutionary history. In addition, the Neuquén Basin is the first site in the Southern Hemisphere where the Toarcian Ocean Anoxic Event (T-OAE) has been documented isotopically. Another objective of my project is to analyze the response of calcareous nannofossils to this event in this part of the world.

I want to contribute to generating a local biostratigraphic scheme, considering the impact of connections and intermittent interactions between the Paleopacific and the Tethys Oceans on the evolution of calcareous nannofossils, and making accurate correlations at a global scale based on existing paleobiogeographic and paleoenvironmental differences. I am endeavoring to produce, for the first time, a supra-regional biostratigraphic synthesis integrating "classical" Tethyan localities from Europe and North Africa with new localities in the Southern Hemisphere.

John Sarao, 2019 Winner of a Katharina von Salis Graduate Research Fellowship

I am currently a PhD student at Texas A&M University (Texas, USA) working jointly with the Department of Geology and Geophysics and the International Ocean Discovery Program (IODP). My project focuses on using marine sediments and calcareous nannofossils to reconstruct the surface water conditions along the eastern margin of the Pacific Ocean over the past 250ka. My research localities include sites along the Chilean Margin in the southern Pacific and Guaymas Basin in the northern Pacific, where I sailed as a nannofossil micropaleontologist on IODP Expeditions 379T (JR100) and 385, respectively. In addition to these sites, NOAA site MV1014-02-17JC from the Panama Basin was chosen to represent the equatorial Pacific.

This project will use high-resolution assemblage data to analyze the planktonic community response to environmental changes such as the introduction of melt water from the Patagonia glacier along the Chilean Margin or migration of the Intertropical Convergence Zone (ITCZ) from the Equatorial Pacific through the Guaymas Basin. This project will also focus on the use and reliability of nannofossil-derived alkenone pCO₂ reconstructions in the Pacific Ocean by examining the carbonate contribution of the alkenone biomarker producers Emiliania huxleyi and Gephyrocapsa oceanica.

Francesco Miniati, 2018 Winner of the Katharina von Salis Graduate Research Fellowship

I am currently a PhD student at the University of Milan (Milan, Italy). My research project, which includes the biostratigraphy and paleoecology of calcareous nannofossils during the Late Cretaceous, is mainly focused on Oceanic Anoxic Event 3 (OAE 3), the youngest OAE (Coniacian-Santonian time interval) of the Cretaceous. It differs from older OAEs in that distribution of organic-rich sediments is restricted to the equatorial to mid-latitude Atlantic Ocean. Additionally, there is no pronounced global δ13C anomaly.

My project aims at characterizing the response of calcareous phytoplankton to the OAE 3 perturbation through quantitative studies of nannofossil assemblages in selected sites of the Atlantic Ocean. These will be compared with sections from other oceanic basins. During my first-year investigations, I observed an increase in abundance of the genus Micula during the Coniacian-Santonian in association with the OAE 3, and I want to verify the tempo, mode and extension of such a change. Implications will be relevant for biostratigraphic correlations and ecosystem modeling.

Lena Wulff, 2017 Winner of the Katharina von Salis Graduate Research Fellowship

My PhD project at the Ruhr-University Bochum (Germany) aims at studying the "Mid Barremian event" (Lower Cretaceous, 125 Ma). This event is represented by black shale depositions, thus it is under discussion in the scientific community, whether it is a so called Oceanic Anoxic Event (OAE) or not. These OAEs are specific and intensively studied features of the Jurassic and Cretaceous period, reflecting short time intervals in which bottom waters of the world's oceans were depleted in oxygen, causing a massive deposition of organic rich sediments.

I want to study the Mid Barremian event with respect to calcareous nannofossil assemblages, their diversity and abundance. By using this group of primary producers I want to contribute to a better understanding of the nature of this paleoceanographic event. Furthermore, I want to understand the impact of the Mid Barremian event as an example for major paleoecological perturbations on calcareous nannofossils.