64PE475: IceAGE_KR expedition to hydrothermal vents North of Iceland Chief-scientist: Sabine Gollner, NIOZ, NL During RV Pelagia expedition 64PE475 to Kolbeinsey, Grimsey, and Strytan vent fields, North of Iceland, we collected samples to study (1) the ecological connectivity at vent field scale (PI Gollner), including distribution of vent faunae and their adaptations to extreme environmental conditions, (2) the role of archaeal symbionts on host evolution and ecology, as well as nutrient cycling (PI Spang), (3) paleoenvironmental records (PI Hennekam), and (4) aided in establishing a potential Icelandic long-term monitoring site (PI Egilsdottir). Our projects are in cooperation with the international project IceAGE (Icelandic marine Animals: Genetics and Ecology, PI Brix) (www.iceage-project.org) that has the mission to explore the diversity of animals that live in deep waters around Iceland. We aim to understand the response and adaptation to extremes that will help us to predict resilience and biodiversity in our changing oceans. The remotely operated vehicle (ROV) Phoca (GEOMAR) was used to (1) take pictures/videos from vent fields, (2) take biological samples (rocks and sediments with associated microbial and faunal communities), (3) deploy/recover faunal settlement substrates and (4) deploy/recover hydrophones at and near hydrothermal vents. In addition, we used CTDs to collect water at different depths above and near venting areas, boxcorers to collect sediment near the Kolbeinsey vents, and multicorers to collect sediments near Grimsey vent. To study paleoenvironmental conditions, we used gravity corers, piston corers and multicorers at five additional locations. To aid establishing an Icelandic monitoring site, an epibenthic sledge was used to collect epifauna during one day dedicated to the monitoring program. Multibeaming was performed to create seafloor maps. The use of ROV Phoca on RV Pelagia was very successful, and a total of 13 dives (6 at Kolbeinsey, 6 at Grimsey, 1 at Stryan) over the span of 10 days could be made. Kolbeinsey vent field is at ~100 m depth and is characterized by a central venting area (up to 160°C) that is surrounded by dense bacterial mats, sponges, and polychaetes. There were no chimneys detected at Kolbeninsey and the area is dominated by hard substrate (Figure 1). Grimsey vent field is at ~400 m depth and is characterized by numerous white chimneys (nine chimneys ranging from 50 cm to several meters in height were observed during our dives), with sedimented areas between chimneys. Maximal temperatures were ~250°C, and bacterial mats, krill, amphipods, fish, anemones, and snails were present at and in close vicinity to vents (Figure 1). At Strytan vent, a 40 m high chimney in 60 meters water depth, a vertical ROV video transect was carried out. At Kolbeinsey and Grimsey vent sites the following sampling was performed: 3 hydrophones deployed/recovered; 8 settlement substrates deployed/recovered; multiple rock and sediment collections to study biodiversity of associated microbes and fauna (at and in close vicinity to vents); CTDs at vent, at 1 km, and 3 km distance to vent; boxcorer/multicorer deployment at 1 and 3 km distance to vent. (2026-06-16)