A review of the dodo and its ecosystem: insights from a vertebrate concentration Lagerstätte in Mauritius

The dodo Raphus cucullatus Linnaeus, an extinct and flightless, giant pigeon endemic to Mauritius, has fascinated people since its discovery, yet has remained surprisingly poorly known. Until the mid-19th century, almost all that was known about the dodo was based on illustrations and written accounts by 17th century mariners, often of questionable accuracy. Furthermore, only a few fragmentary remains of dodos collected prior to the bird's extinction exist. Our understanding of the dodo's anatomy was substantially enhanced by the discovery in 1865 of subfossil bones in a marsh called the Mare aux Songes, situated in southeastern Mauritius. However, no contextual information was recorded during early excavation efforts, and the majority of excavated material comprised larger dodo bones, almost all of which were unassociated. Here we present a modern interdisciplinary analysis of the Mare aux Songes, a 4200-year-old multitaxic vertebrate concentration Lagerstätte. Our analysis of the deposits at this site provides the first detailed overview of the ecosystem inhabited by the dodo. The interplay of climatic and geological conditions led to the exceptional preservation of the animal and associated plant remains at the Mare aux Songes and provides a window into the past ecosystem of Mauritius. This interdisciplinary research approach provides an ecological framework for the dodo, complementing insights on its anatomy derived from the only associated dodo skeletons known, both of which were collected by Etienne Thirioux and are the primary subject of this memoir.publishedVersio

Scour hole ('wielen') sediments as historical archive of floods, vegetation, and air and water quality in lowlands

The sediment record from a maximum 18 m deep scour hole lake (Haarsteegse Wiel) near the embanked Meuse River in the Netherlands was studied for past changes in flooding frequency, water quality, and landscape change using a combined geochemical, geobiological and historical approach. The results are highly significant for determining long-term trends of river flood frequency, eutrophication, atmospheric pollution, and vegetation development. Haarsteegse Wiel consists of two basins connected by a shallow sill. The first flooding event is indicated in the sediment at AD 1610 when the 8 m deep southern basin of the lake was created by flood water masses bursting through the embankment. In AD 1740 embankments burst again and resulted in the formation of the northern basin of Haarsteegse Wiel. This part of the lake was originally 21 m deep and was filled up with a 3.50 m thick sediment layer since then. The sediment was dated by combining 137Cs activity measurements, biostratigraphical ages of pollen, microtephra, and historically documented floods indicated by the magnetic susceptibility of the sediment. The resulting chronology is highly accurate and shows that sedimentation rates decrease sharply with the widespread change from cereal cultivation to pasture land from around AD 1875 (agricultural crisis) as a direct result of falling wheat prices and intensified cattle farming. Water quality (total phosphorus concentration) was reconstructed using a diatom-based transfer function. Results show that the currently nutrient enriched lake has mostly been in a mesotrophic state prior to AD 1920, with the exception of several sharp eutrophication events that are generally coeval with river floods. After 1920, eutrophication of Haarsteegse Wiel is clearly documented and generally caused by the increased population, enhanced use of fertilizers and settlement of dairy industry in the region. Industrial development in both the vicinity and the hinterland of Haarsteegse Wiel since ca. 1880 is also well documented by the accumulation of SCP (Spheroidal Carbonaceous Particles; fly ash) in the sediment. Furthermore, river floods impact the vegetation composition by importing allochtonous components and, triggered by the influx of nutrients, clearly affect the composition of the water plant communities and aquatic species diversity

Geolandschappelijk en archeologisch onderzoek Stroobos : geoarcheologische begeleiding van een nieuw gegraven bermsloot, die aangelegd is in het kader van de bochtverruiming van het Van Starkenborghkanaal bij Stroobos in de zomer van 2003 (provincie Groningen)

Lit. opg

Marine productivity leads organic matter preservation in sapropel S1: palynological evidence from a core east of the Nile River outflow

The formation of Eastern Mediterranean organic matter rich deposits known as sapropels is the results of two mechanisms: (enhanced) marine productivity and preservation of organic material at depth. However, their relative contribution and their leads and lags with respect to each other remain elusive. Here, we address these questions by studying sediments deposited prior to, during, and after the most recent sapropel (S1, ∼10–6 calibrated ka before present, BP) with an integrated marine and terrestrial palynological approach, combined with existing and newly generated geochemical data. The studied core was retrieved from an area under strong influence of the Nile outflow and has high average sediment accumulation rates allowing a high temporal resolution (of several decades to centuries). Marine productivity, as reconstructed with total dinocyst accumulation rates (ARs) and biogenic CaCO3 content, starts to increase ∼1 ka prior to sapropel formation. A shift in the dinocyst taxa contributing to the productivity signal at sapropel onset indicates the rapid development of (seasonal) water column stratification. Pollen and spore ARs also increase prior to sapropel onset, but a few centuries after the increase in marine productivity. Hence, the first shift to a high marine productivity system before sapropel deposition may have been mostly favoured by the injection of nutrients via shoaling of the nutricline with a minor contribution of nutrients from land via river input and flooding of the shelves. Pollen assemblages indicate a gradual change across the sapropel onset from a savanna-like, through coastal marsh expansion, toward an open woodland assemblage, which is consistent with enhanced Nile influence and delta development. At sapropel onset a marked shift in pollen ARs could suggest increased preservation under anoxia. However, major shifts in pollen assemblages and signs of selective- or partial decomposition of terrestrial palynomorphs are absent. We therefore suggest that the high pollen ARs largely result from an increased influx of pollen by enhanced Nile discharge and extension of the freshwater plume. Three centuries after the sapropel onset, dinocyst ARs and CaCO3 content indicate that marine productivity starts to decrease, while sapropel deposition continued. Organic carbon content decreased only later and less dramatically. This may be explained by a shift in the dominance of the organisms contributing to marine productivity, to an enhanced preservation of organic matter, or a combination of both

『源氏大鏡』三類本 本文と校異（三）若紫―花宴

The formation of Eastern Mediterranean organic matter rich deposits known as sapropels is the results of two mechanisms: (enhanced) marine productivity and preservation of organic material at depth. However, their relative contribution and their leads and lags with respect to each other remain elusive. Here, we address these questions by studying sediments deposited prior to, during, and after the most recent sapropel (S1, ∼10–6 calibrated ka before present, BP) with an integrated marine and terrestrial palynological approach, combined with existing and newly generated geochemical data. The studied core was retrieved from an area under strong influence of the Nile outflow and has high average sediment accumulation rates allowing a high temporal resolution (of several decades to centuries). Marine productivity, as reconstructed with total dinocyst accumulation rates (ARs) and biogenic CaCO3 content, starts to increase ∼1 ka prior to sapropel formation. A shift in the dinocyst taxa contributing to the productivity signal at sapropel onset indicates the rapid development of (seasonal) water column stratification. Pollen and spore ARs also increase prior to sapropel onset, but a few centuries after the increase in marine productivity. Hence, the first shift to a high marine productivity system before sapropel deposition may have been mostly favoured by the injection of nutrients via shoaling of the nutricline with a minor contribution of nutrients from land via river input and flooding of the shelves. Pollen assemblages indicate a gradual change across the sapropel onset from a savanna-like, through coastal marsh expansion, toward an open woodland assemblage, which is consistent with enhanced Nile influence and delta development. At sapropel onset a marked shift in pollen ARs could suggest increased preservation under anoxia. However, major shifts in pollen assemblages and signs of selective- or partial decomposition of terrestrial palynomorphs are absent. We therefore suggest that the high pollen ARs largely result from an increased influx of pollen by enhanced Nile discharge and extension of the freshwater plume. Three centuries after the sapropel onset, dinocyst ARs and CaCO3 content indicate that marine productivity starts to decrease, while sapropel deposition continued. Organic carbon content decreased only later and less dramatically. This may be explained by a shift in the dominance of the organisms contributing to marine productivity, to an enhanced preservation of organic matter, or a combination of both

En imitation med original -En diskursanalys av kulturskapande över fältgränser

The purpose of this thesis is to discuss how agents create their culture outside of their ”own” fields. What does this way of creating a culture mean for groups already existing on the field? Who owns the power to construct their own subject positions? Through a discourse analysis, I analyse these questions through articles and interviews treating two cultural fields which I call ”The hip Berlin” and ”Swedish hip hop culture”. I argue that, depending on a persons priviliges, one owns the power not only to construct subject positions of ones own, but also for persons with less privileges in the existing hegonomy of society