Poseidon2LOD (NFDI4Objects Community Meeting 2025)

Integrating complex, interdisciplinary datasets remains a central challenge in digital archaeology and cultural heritage research. In particular, archaeogenetic datasets require standardised storage and formats, as well as interoperable semantic integration with archaeological and natural science data. The Poseidon Framework meets this need by providing a community-maintained archive for archaeogenetic human genotype data. It implements the FAIR principles through a structured package format, command-line tools and open submission workflows. The Poseidon Community Archive (PCA) enables the reproducible reuse of data by linking genomic information with archaeological and laboratory metadata, with transparent provenance and validation mechanisms in place to support this. To facilitate integration of Poseidon data with other archaeo-natural datasets and the NFDI4Objects Knowledge Graph (N4O KG), the presented workflow converts the PCA data into interoperable RDF data. This workflow operates on two levels: (i) data-level standards are established by parsing PCA metadata into RDF triples and enriching them with external identifiers; and (ii) schema-level standards are ensured through the Archaeo-Natural Ontology (ArNO). Grounded in CIDOC CRM, but extended with classes from complementary ontologies, ArNO provides a shared semantic foundation for representing archaeo-natural entities and relations. It enables the consistent mapping of heterogeneous data sources and facilitates their integration into the CIDOC-CRM–based N4O KG. The RDF transformation process consists of several steps. First, averaged coordinate information is derived for sites and places from their associated discovery sites. These entities are then linked to external gazetteers, such as GeoNames and Wikidata, using label similarity and spatial matching. Next, bibliographic metadata are harmonised via the CrossRef API to ensure persistent identifiers, such as DOIs and ORCIDs. Finally, the extracted archaeological, genetic and bibliographic information is translated into ArNO-compliant RDF triples. A demo dataset comprising ancient DNA samples illustrates this approach. This work demonstrates how Poseidon data can be converted into Linked Open Data, ensuring interoperability across domains. By considering the ArNO ontology and leveraging external authority services, this paves the way for the integration of the archaeo-natural data in NFDI4Objects Task Area 3 using graph structures, such as Heterogeneous Information Networks or Knowledge Graphs. This enhances the potential for cross-dataset synthesis and reproducible research, and prepares the ground for advanced analytical methods. Ultimately, Poseidon2LOD contributes to a broader FAIR data ecosystem within NFDI4Objects Task Area 3, supporting the interdisciplinary exploration of the human past through semantically enriched, computationally accessible datasets.