The Late Triassic- Middle Jurassic microfossils from the central european alpids

1 ABSTRACT In the Upper Triassic, the Pangean supercontinent was incised by a large epicontinental sea known as the Tethys Ocean. The junction between oceanic and continental environments formed an extensive zone of shallow seas that served as important catchments for sediment supply. The Alpine sector of the Tethyan shelf refers to the sedimentary rocks found in the modern-day Southern Alps, Northern Calcareous Alps, and Western Carpathians, which preserve records of ancient environmental shifts and paleoecological interactions. Our research aimed to investigate changes in marine microbial ecosystems across the Triassic- Jurassic boundary, focusing specifically on two groups of microscopic organisms: nannolith- forming phytoplankton and microboring organisms. The former reflects environmental conditions in surface waters, while the latter is influenced by bottom-water conditions. Together, these two groups provide a comprehensive view of the paleoceanographic changes that occurred during this critical transitional period. This dissertation summarizes three studies published and submitted in peer-reviewed, high-impact scientific journals. Two of the publications focus on microbioerosional structures, and one on calcareous nannofossils. The changes in morphology and abundance of microborings in the Eastern...