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Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project provides a comprehensive data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from Hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lacustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system. Secondary alteration effects - in particular FeO, MnO, SO3 and F concentrations – are 2 to 10 times higher in fossil than in modern enamel; the secondary enrichment of these components in fossil dentin and cement is even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ∼1%). Linear regression analysis reveals tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40% to 300%) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite trend. Fossil enamel from Hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2O ratio (∼1.11) than those from the Neogene fossils of Lake Albert (MgO/Na2O∼0.4), which was a large fresh water lake like those in the western Branch of the East African Rift System today. Similarly, the MgO/Na2O ratio in modern enamel from the White Nile River (∼0.36), which has a Precambrian catchment of dominantly granites and gneisses and passes through several saline zones, is higher than that from the Blue Nile River, whose catchment is the Neogene volcanic Ethiopian Highland (MgO/Na2O∼0.22). Thus, particularly MgO/Na2O might be a sensitive fingerprint for environments where river and lake water have suffered strong evaporation. Enamel formation in mammals takes place at successive mineralization fronts within a confined chamber where ion and molecule transport is controlled by the surrounding enamel organ. During the secretion and maturation phases the epithelium generates different fluid composition, which in principle, should determine the final composition of enamel apatite. This is supported by co-linear relationships between MgO, Cl and Na2O which can be interpreted as binary mixing lines. However, if maturation starts after secretion is completed, the observed element distribution can only be explained by equilibration of existing and addition of new apatite during maturation. It appears the initial enamel crystallites precipitating during secretion and the newly formed bioapatite crystals during maturation equilibrate with a continuously evolving fluid. During crystallization of bioapatite the enamel fluid becomes continuously depleted in MgO and Na2O, but enriched in Cl which results in the formation of MgO, and Na2O-rich, but Cl-poor bioapatite near the EDJ and MgO- and Na2O-poor, but Cl-rich bioapatite at the outer enamel rim. The linkage between lake and river water compositions, bioavailability of elements for plants, animal nutrition and tooth formation is complex and multifaceted. The quality and limits of the MgO/Na2O and other proxies have to be established with systematic investigations relating chemical distribution patterns to sedimentary environment and to growth structures developing as secretion and maturation proceed during tooth formation.
Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants.
Parasites of the nematode genus Anisakis are associated with aquatic organisms. They can be found in a variety of marine hosts including whales, crustaceans, fish and cephalopods and are known to be the cause of the zoonotic disease anisakiasis, a painful inflammation of the gastro-intestinal tract caused by the accidental consumptions of infectious larvae raw or semi-raw fishery products. Since the demand on fish as dietary protein source and the export rates of seafood products in general is rapidly increasing worldwide, the knowledge about the distribution of potential foodborne human pathogens in seafood is of major significance for human health. Studies have provided evidence that a few Anisakis species can cause clinical symptoms in humans. The aim of our study was to interpolate the species range for every described Anisakis species on the basis of the existing occurrence data. We used sequence data of 373 Anisakis larvae from 30 different hosts worldwide and previously published molecular data (n = 584) from 53 field-specific publications to model the species range of Anisakis spp., using a interpolation method that combines aspects of the alpha hull interpolation algorithm as well as the conditional interpolation approach. The results of our approach strongly indicate the existence of species-specific distribution patterns of Anisakis spp. within different climate zones and oceans that are in principle congruent with those of their respective final hosts. Our results support preceding studies that propose anisakid nematodes as useful biological indicators for their final host distribution and abundance as they closely follow the trophic relationships among their successive hosts. The modeling might although be helpful for predicting the likelihood of infection in order to reduce the risk of anisakiasis cases in a given area.
Acanthocephalans are attractive candidates as model organisms for studying the ecology and co-evolutionary history of parasitic life cycles in the marine ecosystem. Adding to earlier molecular analyses of this taxon, a total of 36 acanthocephalans belonging to the classes Archiacanthocephala (3 species), Eoacanthocephala (3 species), Palaeacanthocephala (29 species), Polyacanthocephala (1 species) and Rotifera as outgroup (3 species) were analyzed by using Bayesian Inference and Maximum Likelihood analyses of nuclear 18S rDNA sequence. This data set included three re-collected and six newly collected taxa, Bolbosoma vasculosum from Lepturacanthus savala, Filisoma rizalinum from Scatophagus argus, Rhadinorhynchus pristis from Gempylus serpens, R. lintoni from Selar crumenophthalmus, Serrasentis sagittifer from Johnius coitor, and Southwellina hispida from Epinephelus coioides, representing 5 new host and 3 new locality records. The resulting trees suggest a paraphyletic arrangement of the Echinorhynchida and Polymorphida inside the Palaeacanthocephala. This questions the placement of the genera Serrasentis and Gorgorhynchoides within the Echinorhynchida and not the Polymorphida, necessitating further insights into the systematic position of these taxa based on morphology.
Recent phylogenomic studies have failed to conclusively resolve certain branches of the placental mammalian tree, despite the evolutionary analysis of genomic data from 32 species. Previous analyses of single genes and retroposon insertion data yielded support for different phylogenetic scenarios for the most basal divergences. The results indicated that some mammalian divergences were best interpreted not as a single bifurcating tree, but as an evolutionary network. In these studies the relationships among some orders of the super-clade Laurasiatheria were poorly supported, albeit not studied in detail. Therefore, 4775 protein-coding genes (6,196,263 nucleotides) were collected and aligned in order to analyze the evolution of this clade. Additionally, over 200,000 introns were screened in silico, resulting in 32 phylogenetically informative long interspersed nuclear elements (LINE) insertion events.
The present study shows that the genome evolution of Laurasiatheria may best be understood as an evolutionary network. Thus, contrary to the common expectation to resolve major evolutionary events as a bifurcating tree, genome analyses unveil complex speciation processes even in deep mammalian divergences. We exemplify this on a subset of 1159 suitable genes that have individual histories, most likely due to incomplete lineage sorting or introgression, processes that can make the genealogy of mammalian genomes complex.
These unexpected results have major implications for the understanding of evolution in general, because the evolution of even some higher level taxa such as mammalian orders may sometimes not be interpreted as a simple bifurcating pattern.
Although climate is known to be one of the key factors determining animal species distributions amongst others, projections of global change impacts on their distributions often rely on bioclimatic envelope models. Vegetation structure and landscape configuration are also key determinants of distributions, but they are rarely considered in such assessments. We explore the consequences of using simulated vegetation structure and composition as well as its associated landscape configuration in models projecting global change effects on Iberian bird species distributions. Both present-day and future distributions were modelled for 168 bird species using two ensemble forecasting methods: Random Forests (RF) and Boosted Regression Trees (BRT). For each species, several models were created, differing in the predictor variables used (climate, vegetation, and landscape configuration). Discrimination ability of each model in the present-day was then tested with four commonly used evaluation methods (AUC, TSS, specificity and sensitivity). The different sets of predictor variables yielded similar spatial patterns for well-modelled species, but the future projections diverged for poorly-modelled species. Models using all predictor variables were not significantly better than models fitted with climate variables alone for ca. 50% of the cases. Moreover, models fitted with climate data were always better than models fitted with landscape configuration variables, and vegetation variables were found to correlate with bird species distributions in 26–40% of the cases with BRT, and in 1–18% of the cases with RF. We conclude that improvements from including vegetation and its landscape configuration variables in comparison with climate only variables might not always be as great as expected for future projections of Iberian bird species.
Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project intends to provide a detailed data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe, to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lakustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system.
Secondary alteration effects in particular FeO, MnO, SO3 and F concentrations, which are 2 to 10 times higher in fossil than in modern enamel; secondary enrichments in fossil dentin and cement are even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ~1 %). Linear regression analysis reveals very tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40 % to 300 %) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite variation.
Fossil enamel from hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2O ratio (∼1.11) than those from the Neogene fossils of Lake Albert (MgO/Na2O∼0.4), which was a large fresh water lake like those in the western Branch of the East African Rift System today. Similarly, the MgO/Na2O ratio in modern enamel from the White Nile River (∼0.36), which has a Precambrian catchment of dominantly granite and gneisses and passes through several saline zones, is higher than that from the Blue Nile River, whose catchment is the Neogene volcanic Ethiopian Highland (MgO/Na2O∼0.22). Thus, particularly MgO/Na2O might be a sensitive fingerprint for environments where river and lake water have suffered strong evaporation.
Enamel formation in mammals takes place at successive mineralization fronts within a confined chamber where ion and molecule transport is controlled by the surrounding enamel organ. During the secretion and maturation phases the epithelium generates different fluid composition, which in principle, should determine the final composition of enamel apatite. This is supported by co-linear relationships between MgO, Cl and Na2O which can be interpreted as binary mixing lines. However, if maturation starts after secretion is completed the observed element distribution can only be explained by recrystallization of existing and addition of new apatite during maturation. Perhaps the initial enamel crystallites precipitating during secretion and the newly formed bioapatite crystals during maturation equilibrate with a continuously evolving fluid. During crystallization of bioapatite the enamel fluid becomes continuously depleted in MgO and Na2O, but enriched in Cl which results in the formation of MgO, and Na2O-rich, but Cl-poor bioapatite near the EDJ and MgO- and Na2O-poor, but Cl-rich bioapatite at the outer enamel rim.
The linkage between lake and river water composition, bioavailability of elements for plants, animal nutrition and tooth formation is complex and multifaceted. The quality and limits of the MgO/Na2O and other proxies have to be established with systematic investigations relating chemical distribution patterns to sedimentary environment and to growth structures developing as secretion and maturation proceed during tooth formation.
Climate change research is increasingly focusing on the dynamics among species, ecosystems and climates. Better data about the historical behaviours of these dynamics are urgently needed. Such data are already available from ecology, archaeology, palaeontology and geology, but their integration into climate change research is hampered by differences in their temporal and geographical scales. One productive way to unite data across scales is the study of functional morphological traits, which can form a common denominator for studying interactions between species and climate across taxa, across ecosystems, across space and through time—an approach we call ‘ecometrics’. The sampling methods that have become established in palaeontology to standardize over different scales can be synthesized with tools from community ecology and climate change biology to improve our understanding of the dynamics among species, ecosystems, climates and earth systems over time. Developing these approaches into an integrative climate change biology will help enrich our understanding of the changes our modern world is undergoing.
Background: Natural history museums receive a rapidly growing number of requests for tissue samples from preserved specimens for DNA-based studies. Traditionally, dried vertebrate specimens were treated with arsenic because of its toxicity and insect-repellent effect. Arsenic has negative effects on in vivo DNA repair enzymes and consequently may inhibit PCR performance. In bird collections, foot pad samples are often requested since the feet were not regularly treated with arsenic and because they are assumed to provide substantial amounts of DNA. However, the actual influence of arsenic on DNA analyses has never been tested. Findings: PCR success of both foot pad and body skin samples was significantly lower in arsenic-treated samples. In general, foot pads performed better than body skin samples. Moreover, PCR success depends on collection date in which younger samples yielded better results. While the addition of arsenic solution to the PCR mixture had a clear negative effect on PCR performance after the threshold of 5.4 μg/μl, such high doses of arsenic are highly unlikely to occur in dried zoological specimens. Conclusions: While lower PCR success in older samples might be due to age effects and/or DNA damage through arsenic treatment, our results show no inhibiting effect on DNA polymerase. We assume that DNA degradation proceeds more rapidly in thin tissue layers with low cell numbers that are susceptible to external abiotic influences. In contrast, in thicker parts of a specimen, such as foot pads, the outermost horny skin may act as an additional barrier. Since foot pads often performed better than body skin samples, the intention to preserve morphologically important structures of a specimen still conflicts with the aim to obtain optimal PCR success. Thus, body skin samples from recently collected specimens should be considered as alternative sources of DNA.
Background: Until recently, read lengths on the Solexa/Illumina system were too short to reliably assemble transcriptomes without a reference sequence, especially for non-model organisms. However, with read lengths up to 100 nucleotides available in the current version, an assembly without reference genome should be possible. For this study we created an EST data set for the common pond snail Radix balthica by Illumina sequencing of a normalized transcriptome. Performance of three different short read assemblers was compared with respect to: the number of contigs, their length, depth of coverage, their quality in various BLAST searches and the alignment to mitochondrial genes. Results: A single sequencing run of a normalized RNA pool resulted in 16,923,850 paired end reads with median read length of 61 bases. The assemblies generated by VELVET, OASES, and SeqMan NGEN differed in the total number of contigs, contig length, the number and quality of gene hits obtained by BLAST searches against various databases, and contig performance in the mt genome comparison. While VELVET produced the highest overall number of contigs, a large fraction of these were of small size (< 200bp), and gave redundant hits in BLAST searches and the mt genome alignment. The best overall contig performance resulted from the NGEN assembly. It produced the second largest number of contigs, which on average were comparable to the OASES contigs but gave the highest number of gene hits in two out of four BLAST searches against different reference databases. A subsequent meta-assembly of the four contig sets resulted in larger contigs, less redundancy and a higher number of BLAST hits. Conclusion: Our results document the first de novo transcriptome assembly of a non-model species using Illumina sequencing data. We show that de novo transcriptome assembly using this approach yields results useful for downstream applications, in particular if a meta-assembly of contig sets is used to increase contig quality. These results highlight the ongoing need for improvements in assembly methodology. Keywords: next generation sequencing; short read assembly; Mollusca
Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources.
Carbon-13 and oxygen-18 abundances were measured in large mammal skeletal remains (tooth enamel, dentine and bone) from the Chiwondo Beds in Malawi, which were dated by biostratigraphic correlation to ca. 2.5 million years ago. The biologic isotopic patterns, in particular the difference in carbon-13 abundances between grazers and browsers and the difference in oxygen-18 abundances between semi-aquatic and terrestrial herbivores, were preserved in enamel, but not in dentine and bone. The isotopic results obtained from the skeletal remains from the Chiwondo Beds indicate a dominance of savannah habitats with some trees and shrubs. This environment was more arid than the contemporaneous Ndolanya Beds in Tanzania. The present study confirms that robust australopithecines were able to live in relatively arid environments and were not confined to more mesic environments elsewhere in southern Africa.
Paläozoische Notizen
(1907)
Unter diesem Titel sollen kleinere Beobachtungen an paläozoischen Fossilien beschrieben werden. Hauptsächlich werden es Stücke des Senckenbergischen Museums sein, jedoch sollen auch Exemplare anderer Sammlungen gelegentlich in Betracht gezogen werden. Die ersten vier der hier beschriebenen Versteinerungen stammen aus den Oberkoblenzschichten von Prüm in der Eifel, wo der Verfasser im Sommer 1905 größere Aufsammlungen machen konnte.
Die Steinauer Höhle
(1914)
Sinopa rapax Leidy
(1913)
Die METEOR-Fahrt 71 umfasst 3 biologisch und biogeochemisch orientierte Fahrtabschnitte mit insgesamt 50 Schiffstagen im östlichen Mittelmeer und hat folgende Ziele: Der Abschnitt METEOR 71-1 dient der physikalischen, biogeochemischen und biologischen Probengewinnung im Bereich der Anaximander Mountains. Es gibt nur einige wenige Seeberge im östlichen Mittelmeeres, die weitgehend isoliert vom übrigen Ozean sind und in einer Region liegen, die sich durch ein im Vergleich zum Weltozean sehr warmes Tiefenwasser von rund 14 °C auszeichnet. Hauptziel der Untersuchungen an einem Gipfel der Anaximander Mountains ist die Beantwortung der Frage, ob sich ein Seeberg-Ökosystem in einer oligotrophen Region mit warmen Tiefenwasser in Bezug auf seinen Einfluß auf das umgebende Strömungs- und Nährstoffregime, die Produktivität und Verteilung der Nahrungsketten, sowie in Bezug auf die Größe der „Sphere of interference“, das heißt dem Einflußbereich des Seamounts auf den umgebenden Wasserkörper, ähnlich verhält wie entsprechende Erhebungen im Nordostatlantik. Die Expedition METEOR 71-2 beschäftigt sich mit der Biodiversität in der Tiefsee des östlichen Mittelmeeres und ihren Steuerungsfaktoren (Tiefe, Küstenabstand, Nahrungsverfügbarkeit). Zum einen geht es um eine möglichst vollständige Erfassung der Artenzusammensetzung in zwei Referenzregionen durch Vielfachbeprobung an der selben Stelle, zum anderen um die Unterschiede des Arteninventars und des Artenreichtums in Abhängigkeit von der Tiefe und vom Küstenabstand. Die Arbeitsgebiete von jeweils 17 sm x 5 sm sind das Ierapetra-Becken südlich Kreta. (> 4000m Tiefe) und ein Gebiet der gleichen Größe weiter südlich (2800 m Tiefe doppelter Abstand zur Küste).Die Untersuchungen berücksichtigen alle Grössenklassen des Benthos (Mega-, Macro-, Meiound Nanofauna), um Gemeinsamkeiten und Unterschiede in der Abhängigkeit der Biodiversität von Ökofaktoren zu erkennen. Damit sollen die Struktur und die Funktion der Lebensgemeinschaften am äußerst oligotrophen Tiefseeboden des levantinischen Beckens besser und detaillierter verstanden werden. Arbeiten der Expedition METEOR 71-3 zielen auf die Klärung der Frage, ob im heutigen Mittelmeer Phosphatverlust und unvollständige Nitratnutzung, oder Stickstoff-Fixierung im ultraoligotrophen östlichen Mittelmeer für isotopisch abgereicherte d15N Signaturen von Sedimenten und Schwebstoffen verantwortlich sind. Ein Nebenziel ist die Gewinnung zusätzlicher Oberflächensedimente, um die Datenbasis für Eichungen des UK´37-Index und Abschätzung der Nährstoffakkumulationsraten in Sedimenten im Mittelmeers zu verbessern. Dazu werden auf Schnitten durch das östliche Mittelmeer Nährstoffprofile beprobt, Proben für Messungen der 15N/14N-Verhältnisse in Nitrat, gelöstem organischem Stickstoff, in Sinkstoffen und Oberflächensedimenten gewonnen, Untersuchungen des Phytoplanktons sowie Messungen von N2-Fixierungsraten durchgeführt. Weiter werden molekulare Techniken eingesetzt, um das Vorhandensein und die Transkription der nifH-Gene für das Nitrogenase-Enzym diazotropher Organismen zu überprüfen. Die Methoden zielen auf das nifHGen und seine Transkripte und geben Aufschluss über das Potential für Stickstofffixierung. Die Ergebnisse werden zeigen, ob das Gen aktiv in der Plankton-Gemeinschaft transkribiert wird. Ferne wird mit der DNA Sequenzanalyse neben der Anwesenheit auch die Diversität der diazotrophen Organismen etabliert. Schließlich wird im Verlauf der Fahrt an einer Station im Rhodos-Becken eine Sedimentfalle ausgebracht.
Die Meteor-Reise 63 befasst sich mit zwei unterschiedlichen Themen. Zum einen soll die Klimageschichte des Agulhas-Stroms sowie die spätpleistozäne und holozäne Klimage-schichte rekonstruiert und werden. Der zweite Fahrtabschnitt befasst sich mit Biodiversi-tätsgradienten in der abyssalen Tiefsee des Atlantik. Die Reise Meteor 63 soll somit Grundlagenwissen zur marinen Umwelt der Tiefsee um Afrika liefern, sowie deren kurz- und langfristige Variabilität zu erklären helfen.
Die fünf Abschnitte der Meteor-Reise 48 führen in die Zone der Ostrandzirkulation des Südost-Atlantiks und verknüpfen ozeanografische, biologische, geologische und chemische Arbeiten im Bereich des Auftriebsgebietes vor der südwest-afrikanischen Küste sowie im Pelagial des Angolabeckens und des Kapbeckens. Die Arbeiten konzentrieren sich auf · die Biodiversität von Benthosgemeinschaften in Tiefseebecken, · biogeochemische Stoffkreisläufe und kurzskalige holozäne Klimavariationen im Auftriebsgebiet vor Namibia, · die Dynamik des Angola Domes und des Benguelastromes und die Entstehung des Südäquatorialen Gegenstroms im Atlantik, · die Verteilungen von Spurenelementen und natürlichen Radionukliden im Auftriebsgebiet vor Namibia, · den Einfluss mesoskaliger physikalischer Strukturen und Prozesse auf die Produktion des Zooplanktons im nördlichen Benguela-Auftriebssystem.
Die Meteor-Reise 60 besteht aus 5 Fahrtabschnitten im subtropischen Wirbel des Nordatlantiks von den Azoren bzw. Madeira bis zum tropischen Westatlantik. Fahrtabschnitt 1 konzentriert sich auf die Ökologie und Biogeochemie von sogenannten „Seamounts“ im östlichen Atlantik im Rahmen eines EU-Projektes; Fahrtabschnitt 2 umfasst, in Zusammenarbeit mit französischen Kollegen, detailierte seismische und geophysikalische Untersuchungen eines aktiven Segments des Mittelatlantischen Rückens; Fahrtabschnitt 3 ist eine multidisziplinäre (geologisch, biologisch und chemisch) Untersuchung über die Auswirkungen der hydrothermalen Zirkulation am Mittelatlantischen Rücken im Rahmen eines DFG-Schwerpunkt-programms; Fahrtabschnitt 4 ist einer physikalisch-ozeanographische Studie der langfristigen Variation der thermohalien Zirkulation in westlichen Becken des Atlantiks im Kontext des BMBF-CLIVAR programms gewidmet; und Fahrtabschnitt 5 schließlich, ist eine multidisziplinäre (chemisch/biologisch) Untersuchung über die CO2-Aufnahme und die biologische Pumpe in der Wassersäule des nordatlantischen Subtropenwirbels (DFG-Sonderforschungsbereich 460). Der erste Fahrtabschnitt der Reise M 60 dient der physikalischen, biogeochemischen und biologischen Probengewinnung im Rahmen des EU- Projektes OASIS (OceAnic Seamounts: an Integrated Study). OASIS ist ein interdisziplinäres Projekt mit 9 Partnern aus 5 europäischen Ländern und untersucht die funktionale Charakteristik von Seamount-Ökosystemen. Basierend auf 2 Fallstudien werden die Prozesse, die Seamount-Ökosysteme charakterisieren, und ihre Einflüsse auf den umgebenden Ozean beschrieben. Die wissenschaftlichen Ergebnisse, zusammengeführt in einem konzeptionellen Ökosystemmodell, werden Ausgangsbasis für die Entwicklung von generellen und ortspezifischen Managementplänen sein. Das primäre Ziel von OASIS, eine holistische Erfassung von Seamount-Ökosystemen, wird durch die Integration folgender Sachgebiete erreicht: a) Identifikation und Beschreibung der physikalischen Einflußkräfte auf Seamount-Ökosysteme b) Erfassung der Herkunft, Qualität und Dynamik partikulärer organischer Substanz in der Wassersäule und an der Sedimentoberfläche c) Beschreibung von Aspekten der Biodiversität und Ökologie von Seamount-Lebensgemeinschaften und Erfassung ihrer Dynamik und Produktionsmechanismen d) Modellierung der trophischen Ökologie von Seamount-Ökosystemen e) Anwendung der wissenschaftlichen Ergebnisse auf den Naturschutz. Ein weiteres Ziel der Fahrt ist die Erprobung eines neu entwickelten Drucklabors zur Untersuchung von Tiefseeorganismen unter in situ-Druckbdingenungen von bis zu 500 bar.
Phykologie - Blütezeiten und Ruhepausen einer Wissenschaft im Nebenamt (Fallbeispiel Grünalgen)
(2002)
Phykologie (Algenforschung) ist der Öffentlichkeit dem Namen nach und als wissenschaftliche Disziplin kaum geläufig. Innerhalb der Botanik (Biologie) besteht die Algenkunde gleichsam "implizit" als eine Vielfalt von Entwicklungssträngen, die selten gebündelt sind, vielmehr leicht immer wieder abreißen können, denen sich aber immer wieder auch neue Stränge hinzugesellen. Die Phykologie erforscht, im Gegensatz etwa zum Studium der Blütenpflanzen, nur wenige aus dem Alltagsleben vertraute Gewächse. Ihre Untersuchungsobjekte wurden (und werden immer noch) erst nach und nach entdeckt, weshalb sich die Vorstellung, was eine Alge ist, ständig wandelt. Viele sind ohne Mikroskop gar nicht wahrzunehmen. Forschungsgegenstand und Forschungsaufgabe bilden durch ihre fortwährende Umgestaltung die Leitgedanken der Botanik und Biologie überhaupt ab, wobei die Beziehung reziprok ist. Eine lebhafte Fluktuation von ausübenden Personen und Paradigmata ist ebenso charakteristisch für die Phykologie wie eine ausgeprägte Inter- bzw. Transdisziplinarität und ein hohes aktives internes Innovationspotential. Am Beispiel der traditionellen, heute so nicht mehr bestehenden, »Chlorophyta« wird untersucht, wie diese Sippe zunächst für makroskopisch sichtbare Meeresalgen etabliert wurde. Dann wurden ihr schrittweise verschiedene binnenländische Formenkreise von Algen zugeordnet, bis hin zu den grünen Phytoflagellaten. In der jüngsten Entwicklungsphase haben sich die "grünen Algen" als heterogener Komplex mehrerer voneinander unabhängiger Entwicklungslinien erwiesen, die bis auf eine über das Niveau der Algen nicht hinausgekommen sind, wohl aber zum Landleben fähige Vertreter haben. Als Wurzelbereich der echten Landpflanzen erwies sich überraschend ein kleiner Verwandtschaftsbereich der Algenklasse der Charophyceae.
Background The phylogenetic tree of Galliformes (gamebirds, including megapodes, currassows, guinea fowl, New and Old World quails, chicken, pheasants, grouse, and turkeys) has been considerably remodeled over the last decades as new data and analytical methods became available. Analyzing presence/absence patterns of retroposed elements avoids the problems of homoplastic characters inherent in other methodologies. In gamebirds, chicken repeats 1 (CR1) are the most prevalent retroposed elements, but little is known about the activity of their various subtypes over time. Ascertaining the fixation patterns of CR1 elements would help unravel the phylogeny of gamebirds and other poorly resolved avian clades. Results We analyzed 1,978 nested CR1 elements and developed a multidimensional approach taking advantage of their transposition in transposition character (TinT) to characterize the fixation patterns of all 22 known chicken CR1 subtypes. The presence/absence patterns of those elements that were active at different periods of gamebird evolution provided evidence for a clade (Cracidae + (Numididae + (Odontophoridae + Phasianidae))) not including Megapodiidae; and for Rollulus as the sister taxon of the other analyzed Phasianidae. Genomic trace sequences of the turkey genome further demonstrated that the endangered African Congo Peafowl (Afropavo congensis) is the sister taxon of the Asian Peafowl (Pavo), rejecting other predominantly morphology-based groupings, and that phasianids are monophyletic, including the sister taxa Tetraoninae and Meleagridinae. Conclusions The TinT information concerning relative fixation times of CR1 subtypes enabled us to efficiently investigate gamebird phylogeny and to reconstruct an unambiguous tree topology. This method should provide a useful tool for investigations in other taxonomic groups as well.