What is a Metadata-Lake and Why are We Building One?

Universities turn out to have a lot of research data. This data is sometimes: obvious, not obvious, or even hidden; and can be itself: structured, semi-structured, or unstructured. To have an insight into their data products, collections, and responsibilities, for: administration, discoverability, and demonstration for funding agencies, university libraries will have to build central data catalogs. In this regard, the University and State Library of Münster is building a so-called metadata-lake, aiming to tackle these pressing challenges. In this contribution I will delineate the metadata-lake data-architecture, and its meaning for subject-specific NFDI consortia.