Cruise Report HHUMTL22

The HHUMTL22 cruise onboard R/V Helmer Hanssen was an initiative by The Arctic University Museum of Norway (UMAK) aimed at sampling marine fauna for the museum collections and various research projects undertaken at the museum. Researchers from the Swedish Museum of Natural History and the Department of Evolutionary Biology at the University of Vienna also participated in the cruise. Cruise leader was Andreas Altenburger (UMAK).


Introduction
The HHUMTL22 cruise onboard R/V Helmer Hanssen was an initiative by The Arctic University Museum of Norway (UMAK) aimed at sampling marine fauna for the museum collections and various research projects undertaken at the museum. Researchers from the Swedish Museum of Natural History and the Department of Evolutionary Biology at the University of Vienna also participated in the cruise. Cruise leader was Andreas Altenburger (UMAK).

Itinerary
The HHUMTL22 cruise embarked from Tromsø, Norway at 13:00 CET on Monday the 22 nd of August 2022 and ended in Longyearbyen, Svalbard on Monday the 29 th of August 2022 at 08.00 CET. The total distance travelled was about 900 nautical miles and the total time spent at sea amounted to 163 h (6 days 19 h). Travel and sample processing time during the cruise amounted to 143,5 h (5 days 23,5 h) while the time used for taking the samples was 19,5 h. In total, 9 stations were sampled (Fig. 1).

Project summaries
During the HHUMTL22 cruise, marine fauna for the following research projects was sampled.
1. Distribution and DNA barcoding of marine zooplankton along European coasts. Marine invertebrate animals such as annelids, mollusks, crustaceans, and many others commonly undergo a biphasic life cycle. Thereby, the usually benthic adult forms are antedated by free-swimming larvae that serve as dispersal stages. Since many of these larval types may live in the plankton for several weeks or even months, they may travel large distances by oceanic currents and thus may commence their adult life far from their parental habitat. While some marine invertebrates that exhibit larval stages develop taxon-specific structures in later larval stages (so-called secondary larvae), the primary larval type is often strikingly similar across distantly related taxa, as, e.g., exemplified in the trochophore-type larva of numerous lophotrochozoans or the nauplius of crustaceans. This makes determination of these minute animals -many of them are in the size range of around 100-500 µm or even smaller -down to the species or genus level impossible, even by modern morphological studies. Therefore, DNA barcoding/metabarcoding using commonly available primers have established themselves as the current gold standard to efficiently assign such life cycle stages to their known adult kin. The present project is embedded in a large-scale approach to categorize and assess the biodiversity of invertebrate zooplankton species across major coastal oceanic regions of Europe using these methods in combination with molecular phylogenetic analyses. The results will form an important database for long-term studies revolving around population shifts and biodiversity loss of marine species in the light of ocean warming and acidification inflicted by the ongoing climate change. Samples are to be taken at selected sites from Southern to Northern Europe over the coming years. The northernmost part of the European continent around Northern Norway including Svalbard thereby constitutes a major landmark collecting site for a complete survey of European waters. a. PI: Andreas Wanninger b. Sampling gear: WP2 plankton nets (64µm, 180µm) 2. The project MIRevolution asks if there is one driving force of animal evolution that explains the immense diversity of life. And if this force can help us to understand the exceptional success of parasitic species that affect us? The underlying and very strong feature of both processes seems in fact to be very small: microRNAs. Since the discovery that they are found in all animals and regulate important biological processes about 20 years ago, these tiny fine-tuners of cellular programs are among the most studied molecules ever. However, with more than 16,000 annual publications in 2021, the rapidly growing microRNA field became riddled with contradicting reports that hindered novel discoveries and applications. In the recent research of Dr. Bastian Fromm, this was addressed with the microRNA gene database MirGeneDB and the foundations to transform the microRNA field from a qualitative research area to the quantitative level, and ask fundamental questions, were laid. In this TFS-project, Dr. Fromm and his group will use novel sequencing approaches, state of the art single cell experiments and take advantage of the unique biodiversity in Northern Norway and around Svalbard, to deepen the understanding of animal evolution. Using microRNAs, open questions in systematics and gene-regulation will be addressed. For MIRevolution the cruise will examine selected marine invertebrates for molecular analyses, genome sequencing and microRNA sequencing.
a. PI: Anju Angelina Hembrom b. Sampling gear: WP2 plankton nets, triangular dredge, multi-corer, epibenthic sledge 3. Megafaunal benthic diversity in the Barents Sea and the Seas around Svalbard. Benthic megafauna comprises marine animals exceeding 0,5 -1 cm in size. The benthic fauna plays an important role in marine ecosystems as recyclers of sedimented organic matter, and as link from the benthic to the pelagic food-webs. The benthic fauna in the Barents Sea is influenced by Atlantic and Arctic water masses. For this project benthic marine invertebrates were identified to their lowest taxonomical level and the findings will subsequently be published as a dataset to the Global Biodiversity Information Facility (GBIF). Some specimens were fixed and included in the marine invertebrate collection of the Arctic University Museum of Norway (UiT). a. PI: Andreas Altenburger, Joel Vikberg Wernström b. Sampling gear: WP2 plankton nets, triangular dredge, multi-corer, epibenthic sledge 4. Taxonomy of benthic meiofauna from the Barents Sea. Meiofauna is defined as the fraction of metazoans that pass through a 1 mm mesh size sieve but are retained by a 45 µm mesh. To investigate the biodiversity of meiofauna around Svalbard with a special focus on kinorhynchs, sea floor samples were taken with a multi-corer to explore the diversity of benthic meiofauna around Svalbard. Live kinorhynchs were collected for an attempt of culturing, a challenge that has so far not been solved by any research group.
In addition, specimens of benthic meiofauna were sampled for the marine invertebrate collection of the Arctic University Museum of Norway. a. PI: Joel Vikberg Wernström, Andreas Altenburger b. Sampling gear: triangular dredge and multi-corer 5. Taxonomy, biodiversity and neuroanatomy of the taxon Pycnogonida (Arthropoda). Pycnogonida (sea spiders) are exclusively marine, benthic chelicerates. In many oceanic regions -including the Barents Sea and the waters around Svalbard -their biodiversity is incompletely documented and modern taxonomic studies integrating DNA sequencing and morphology are still scarce. During the cruise, benthic samples were checked for sea spiders and most of the specimens obtained were fixed for integrative taxonomic work at the University of Vienna. Beyond taxonomy, some of the samples taken will be used for invasive neuroanatomical studies seeking to shed light on structural transformations of the central nervous system during early chelicerate evolution. a. PI: Georg Brenneis b. Sampling gear: triangular dredge and epibenthic sledge 6. Evolution of nematodes. Early branching of the nematode tree as well as the relationships between nematodes and other seemingly closely related organisms remain unclear. The goal was to collect representatives from several early branching clades, including some enigmatic parasites from a sea urchin, Strongylocentroctus drobachiensis, for genomic sequencing. If successful, these newly generated genomes will be included in a broad phylogenomic study aimed to improve our understanding of the evolution of Ecdysozoa in general and nematodes in particular, mined for Hox genes in a study looking to understand the evolution of homeodomains, and mined for genes involved in the evolution of parasitism. a. PI: Oleksandr Holovachov b. Sampling gear: triangular dredge, multi-corer 7. Diversity of Monogenean and Digenean flatworms -parasites of fish in the North Sea. Historically, and understandably, most of the studies of fish parasites in the Nordic countries has been focused on commercial species of fish, while the remaining, and much more diverse fish species have been largely neglected. Seven species of fish were collected by a bottom trawl and one by a triangular dredge. All were dissected following standard techniques and gills and digestive system were examined for parasites. Seven species were infected at least in one of the examined organs. These parasites will be identified to species level, sequenced, and included in the current project " Taxonomy (Fig. 6) in 4 % PFA/SW for morphological analysis. Fixation of several ctenophores, small bivalves, zoea larvae and holothurian larvae/juveniles in 4% PFA/SW, ethanol and RNAlater for DNA barcoding, transcriptomics and morphological analysis. 10:28, HH station 1308, triangular dredge (Fig. 7), at 75 53.662645 N, 22 27.006057 E. Shellygravel substrate. The dredge came up with a lot of shells, annelids (including scale worms), a few brittle stars, bryozoans, one nudibranch, and sipunculids, holothurians (incl. Cucumaria frondosa), Pagurus sp., Buccinum sp. and Hyas araneus. An assemblage of nematodes were collected and fixed for morpho-taxonomic studies. Meiofauna was extracted using MgCl2 anaesthesia, and 1 kamptozoan was preserved in 96% ethanol for sequencing and 2 others were preserved in 4% PFA/SW for morphological study, along with meiofaunal copepods and annelids.   17:11, HH station 1313, multi corer (Fig. 9), 76 37.381056 N, 23 07.654756 E, 174 m depth. Excellent mud conditions. The upper 2 cm of each core were taken for extraction of meiofauna. An aplacophoran mollusc, Chaetoderma nitidulum, was preserved for possible molecular study. This sample had a more diverse nematode fauna than 1312, which were also fixed for morphotaxonomic studies. Meiofauna was extracted using the 'bubble and blot' method. Plenty of kinorchynchs were found, and 40 were saved for the culturing attempt, 15 were preserved in SW and frozen for genomics, 10 fixed in RNALater and frozen for the MIRevolution project, and 3 were preserved in 4% PFA/SW for morphological study.   (Fig. 10). Water was taken from the CTD rosette's Niskin bottles and filtered to prepare 4% PFA/SW for fixation.  Muddy substrate with Ctenodiscus crispatus, Ophiura sp., Hormathia digitata, Pectinariidae, and six large pycnogonid specimens (Nymphon cf. tenellum). One pycnogonid was fixed for genome and microRNA sequencing, the remaining five specimens were preserved for taxonomic and neuroanatomical studies. One pycnogonid was also fixed for the MIRevolution project. Accidentally collected in the dredge, an eelpout fish (Lycodes gracilis) was examined for parasites -a monogenean flatworm was found on its gills.  Good mud for extraction of meiofauna, which was done using the 'bubble and blot' method. Kinorhyncha were fixed for the MIRevolution project (11 specimens in RNALater), morphological examinations (3 speciemens in 4% PFA/SW), and genomics (10 specimens). An assemblage of nematodes were fixed for morpho-taxonomic studies.  (Fig. 11). Water was taken from the CTD rosette's Niskin bottles and filtered to prepare 4% PFA/SW for fixation. Almost no fluorescence, hence no phytoplankton. Therefore, only 64 µm mesh in subsequent plankton tows.  Hemithiris psittacea were fixed for the MIRevolution project. Eight juvenile and subadult pycnogonids of the genus Nymphon (Nymphonidae), seven (sub)adults of the genus Eurycyde (Ascorhynchidae), and seven juveniles and subadults of the genus Pseudopallene (Callipallenidae) were preserved for taxonomic and neuroanatomical studies. Nematodes were extracted from a large sponge that was collected by the dredge -a yet unidentified species of Leptosomatidae was transported alive and will be used for genome sequencing. Other nematodes were fixed for morpho-taxonomic studies. Meiofauna was extracted using the MgCl2 method, and many halacarid mites in addition to some harpacticoid copepods and annelids were preserved in 96% ethanol for sequencing and 4% PFA/SW for morphological study.   (Fig. 13). Water was taken from the CTD rosette's Niskin bottles and filtered to prepare 4% PFA/SW for fixation.

Permits
Relevant permits for the fieldwork were applied for prior to the cruise. These included an application to the governor of Svalbard regarding fieldwork in Svalbard (RiS-1D12021Al) and an application to the Norwegian Directorate of Fisheries for permission to trawl (21/16250). Both activities were granted permission within the boundaries of the law.