Tertiary flora of Saxony

The thesis represents the first part of a reference book to the Tertiary flora of Saxony. All taxa based on leaves of angiosperms and on Ginkgo are included in this compendium. After an overview about the geological state of knowledge on the Tertiary in Saxony, phytostratigraphic concepts are introduced and a historical survey on the Tertiary paleobotanical research in Saxony is given. All plant macrofossils published from Saxonian Tertiary until end of 2013 and their sites of discovery (primary data) were recorded. This data were supplemented by additional attributes and unified through project-based M.Sc. theses. Subsequently, taxa of fossil leaves were selected, their data evaluated and brought to a consistent state of research. Data sheets for 187 out of 235 examined taxa were established for a determination atlas. Macro- and micromorphological attributes are described in this atlas and information are given about the systematic, synonymy, palaeoecology and spatial and temporal distribution. The describing part is illustrated by images and instructive drawings. The documented data were surveyed and discussed related to their quality within the literature in the result part. A bibliography of the extensive palaeobotanical literature for plant fossils of Saxony completes the work. The taxon and locality related data are implemented into an open source geographical information system (GIS) in order to visualize and to manage them effectively. For the first time, the results of this thesis implemented in the GIS allow the generation of distribution maps for the taxa of leaves of Tertiary angiospermes and Ginkgo in Saxony. Furthermore it enables to query topographical, geological and paleobotanical information about the fossil sites. A determination key was developed for the fossil material that allows a rough determination of the findings in the field. The compendium will be available for free use in a printed as well as in a digital version.

Combined effects of ocean acidification and light or nitrogen availabilities on 13C fractionation in marine dinoflagellates

Along with increasing oceanic CO2 concentrations, enhanced stratification constrains phytoplankton to shallower upper mixed layers with altered light regimes and nutrient concentrations. Here, we investigate the effects of elevated pCO2 in combination with light or nitrogen-limitation on 13C fractionation (epsilon p) in four dinoflagellate species. We cultured Gonyaulax spinifera and Protoceratium reticulatum in dilute batches under low-light (LL) and high-light (HL) conditions, and grew Alexandrium fundyense and Scrippsiella trochoidea in nitrogen-limited continuous cultures (LN) and nitrogen-replete batches (HN). The observed CO2-dependency of epsilon p remained unaffected by the availability of light for both G. spinifera and P. reticulatum, though at HL epsilon p was consistently lower by about 2.7 per mil over the tested CO2 range for P. reticulatum. This may reflect increased uptake of (13C-enriched) bicarbonate fueled by increased ATP production under HL conditions. The observed CO2-dependency of epsilon p disappeared under LN conditions in both A. fundyense and S. trochoidea. The generally higher epsilon p under LN may be associated with lower organic carbon production rates and/or higher ATP:NADPH ratios. CO2-dependent epsilon p under non-limiting conditions has been observed in several dinoflagellate species, showing potential for a new CO2-proxy. Our results however demonstrate that light- and nitrogen-limitation also affect epsilon p, thereby illustrating the need to carefully consider prevailing environmental conditions.