Mare Incognitum is maintained by researchers at the Institute for Arctic and Marine Biology at UiT The Arctic University of Norway. Mare Incognitum provides a platform to showcase ongoing and recently finished projects dealing with different aspects of Arctic marine ecology lead by researchers at UiT, colleagues within the ARCTOS network as well as international partners. Mare Incognitum also showcases infrastructure such as the Kongsfjorden and Rijpfjorden Observatory Program (KROP) and the ArcLight observatory in Ny-Ålesund.
UiT kindly offered us extra ship time to service the moorings in Kongsfjorden and Rijpfjorden prior to the UNIS cruise, when we usually do this work. Thus, The Special Cruise took place from 18-30 August 2021. Due to the short notice and the need to either quarantine or be fully vaccinated, only five scientific staff participated, joining at different parts of the cruise.
The main objective of the cruise was the recovery and re-deployment of moorings in Kongsfjorden and Rijpfjorden. In addition, water samples and zooplankton samples were taken at standard stations in Isfjorden, Kongsfjorden, Rijpfjorden and Smeerenburgfjorden, and we took the opportunity to explore the zooplankton community in Wijdefjorden.
This one is from our backyard here in Tromsø. Based on monthly sampling between November 2018 and February 2020 we document the seasonal variability in the mesozooplankton community structure in Ramfjord, a sub-Arctic fjord in Northern Norway. By combineing traditional morphological zooplankton identification with DNA metabarcoding of a 313 base pair fragment of the COI gene we provide the most detailed mesozooplankton species list known for this region across an entire year, including both holo- and meroplankton. Both the traditional community analysis and metabarcoding were highly complementary and with a few exceptions showed similar trends in the seasonal changes of the zooplankton community structure.
In situ observations of pelagic fish and zooplankton with optical instruments usually rely on external light sources. Using hull-mounted echosounders above an acoustic probe or a baited video camera, each equipped with light sources of different colours (white, blue and red), we demonstrate that pelagic organisms in Arctic and temperate regions strongly avoid artificial light, including visible red light (575–700 nm), from instruments lowered in the water column. The density of organisms decreased by up to 99% when exposed to artificial light and the distance of avoidance varied from 23 to 94 m from the light source, depending on colours, irradiance levels and, possibly, species communities.This study was conducted during the Polar Night Cruise in January 2020 and in Newfoundland in spring 2020.
Using acoustic records, Hobbs et al. show that zooplankton in an Arctic fjord position themselves vertically in relation to light. A depth-varying line of constant light intensity (isolume) bascially forms a ceiling above which zooplankton won’t venture.The value of this isolume is set at the lower limit of photobehaviour reponses of Calanus spp. and krill. These results suggest that zooplankton follow a foraging strategy that will keep visual predation risk roughly constant under changing light conditions. Thus they already have a strategy to cope with climate induced changes in the under water light climate, such as those caused by the reduction of sea ice.
We were lucky enough to get ship time with UiT’s research vessel Helmer Hanssen this autumn, despite all the social distancing restrictions. With a scientific crew consisting of only 13 people we went from Tromsø to Svalbard to service the ocean observatories (KROP) in Kongsfjorden and Rijpfjorden, maintain the photographic benthos time series in Kongsfjorden, Smeerenburg and Isfjorden, and to conduct some experimental work for CalAct. Everyone was happy to get out of the (home) office, the sea was mainly calm, and best of all: the Rijpfjorden mooring was still there! Ice conditions in 2019 made it impossible to get into Rijpfjorden last year, and the lost of the Kongsfjorden mooring due to corossion last year had made us a bit anxious, but the retrival was successfull and 2 years of data have been recorded!
In July 2019, a set of ArcticABC ice tethered observatories (ITOs) got deployed from R/V Kronprins Haakon at about 84°N. The ITOs consisted of an Acoustic Zooplankton Fish Profiler (AZFP), a Sea-Ice Mass Balance Array (SIMBA), an automated weather station (AWS) and the newly designed high-sensitivity Light & Temperature chain (LT-ITO). During the drift, the SIMBA, AWS and LT-ITO were unfortunately lost at some point. Their data is safe though, as it was transmitted by Iridium. The AZFP data was successfully downloaded by a data harvesting plane with the help of a broadband radio, only a short time before the AZFP-ITO was washed ashore on the northern coast of Iceland. The surface buoy has been recovered by Icelandic SAR, but the AZFP is unfortunately lost. We have the position of an object in the water closed to where the unit beached itself, which we will check out once the Corona restrictions are eased.
Mare Incognitum is an umbrella platform to showcase ongoing projects of researchers at UiT The Arctic University of Norway with other institutes and universities in northern Norway and across the globe. Mare incognitum provides a platform to post news, links, publications and to present team members. The site is maintain by the research group of Prof. Jørgen Berge at UiT, Tromsø, Norway.