The Gothenburg University Marine Algae Culture Collection (GUMACC): A Nordic resource for marine microalgal research, biotechnology and education

The Gothenburg University Marine Algae Culture Collection (GUMACC) is a regionally specialized Nordic resource for marine microalgal research, biotechnology and education. The collection has a focus on Scandinavian coastal, brackish, and polar environments and is particularly rich in diatoms, including a large representation of Skeletonema marinoi . In this resource review we summarize the taxonomic and geographic composition of the collection, describe the public GUMACC database, and provide a complete strain inventory. The public database currently includes 80 strains and represents the historically established public core of the collection rather than the full currently maintained inventory of over 450 strains. We also review how GUMACC strains have supported research in taxonomy and systematics, ecophysiology, climate-change biology, genomics, environmental monitoring, biotechnology and bioresource development. Examples include description of new diatom taxa, studies of responses to temperature, salinity, carbon dioxide, nutrients and ultraviolet radiation, and the establishment of Skeletonema marinoi R05AC as a genetic model for chain-forming marine diatoms. Applied studies have explored lipid production for biodiesel, wastewater remediation, bioactive compounds, and diatom photonic materials. GUMACC also contributes to university teaching, school activities, museum exhibitions, and ocean-literacy initiatives. We discuss current challenges such as the reliance on serial subculturing, variable levels of strain documentation, incomplete public database coverage and the need for improved long-term preservation strategies. Finally, we identify future priorities for strengthening the collection. These include public database updating, expanded genomic and targeted transcriptomic characterization, integration with global biodiversity databases, and targeted expansion of Arctic and sub-Arctic strains relevant to climate resilience.