Cruise Report RV Heincke HE519

• Main Authors: Mark, Felix Christopher, Gentz, Torben, Rokitta, Sebastian
• Format: Other/Unknown Material
• Language: unknown
• Published: 2019
• Subjects: Alfred Wegener Institute; atlantic cod; Bear Island; Bjørnøya; Fugløy*; Gadus morhua; Hornsund; Lofoten; Norwegian Sea; Ocean acidification; polar cod; Svalbard; Vestfjorden; Troms
• Online Access: https://epic.awi.de/id/eprint/51861/; https://epic.awi.de/id/eprint/51861/1/CruiseReport_HE519.pdf; https://hdl.handle.net/10013/epic.1752a376-23a4-4748-be94-2dbd789cab4d

The main objectives of this cruise were to elucidate whether climate change (mainly ocean acidification and warming, OAW) affects interacting species differently due to divergent physiological optima and ranges, expressed in thermal tolerance windows and associated performance capacities and phenologies of specific life stages. To determine the degree of the ongoing ‘Atlantification’ of the waters around (Western) Svalbard, we took sediment samples to analyse the benthic epi- and meiofauna. Further, we intended to obtain specimens of both Polar cod (B. saida) and Atlantic cod (G. morhua) in the Atlantic and polar waters around Svalbard, which were used in experiments on board and back at the Alfred Wegener Institute. We left port in Trondheim in the morning of September 21st, heading North towards Svalbard. Due to severe storms in the Norwegian Sea, we had to travel close to the Norwegian shoreline and eventually seek shelter inside Vestfjorden/Lofoten Islands until September 25th. A second attempt to reach Bjørnøya (Bear Island) on September 26th failed again due to weather, this time weathering off in Fugløysund/Troms (see figure 1 for cruise track). Around noon of September 28th, we finally reached the first scientific station at Bjørnøya (HE519_1), where we deployed a CTD and two short bottom trawls (mainly Atlantic cod, Gadus morhua, and haddock, Melanogrammus aeglefinus) and continued to the Southern tip of Svalbard to reach Hornsund in the morning of September 29th. The first station at Svalbard was carried out in Hornsund (HE519_2), where a CTD and a multicorer was deployed, to sample the water column and first 30cm of sediment. Following this, we ran several juvenile fish trawls with fish lift at different depths from surface waters to close to the bottom, specifically aiming for flocks of juvenile fish under the surface, at the thermocline and above ground (water layers of interest derived from CTD and EK80 profiles). This daily sampling protocol was repeated at all other stations unless stated ...