Biomarkers are organic compounds with an unambiguous link to specific precursor molecules in living organisms. Therefore, biomarkers can be used to track organism abundance, community composition or environmental changes. Compound-specific isotope studies can help answer palaeoclimatic questions such as origin, transport and preservation of organic matter. Over the course of their life, organisms are influenced by a variety of environmental conditions which in turn may influence the chemical and isotopic composition of individual biomarkers. Biomarkers are furthermore subject to transport and alteration processes such as remineralization and diagenesis. In order to reconstruct palaeoenvironments and past climate conditions it is important to understand how these processes and their interactions affect the final biomarker signal. On the other hand, microfossils can often be recovered in large quantities from relatively small samples. Diatoms, pollen, foraminifera, dinoflagellates, ostracods, chironomids and others are picked, identified and enumerated and eventually lead to a comprehensive and often detailed interpretation of the past environment. Multiproxy micropalaeontological approaches are increasingly common but it is not always easy to find interpretations that are consistent with the indications of all the proxies utilized, and such studies would often benefit from a more critical consideration of the assumptions and limitations of the methods used. The aim of this session is to explore the potential and constrains of biomarker-and microfossil-based proxies in palaeoceanographic and palaeoclimatic studies. We invite presentations of palaeoenvironmental studies (marine and freshwater) that focus on two or more biological proxy groups and their interpretation; we particularly welcome critical evaluations of the effectiveness of multiproxy approaches.