Lacydonia (Polychaeta: Phyllodocida) is a poorly known genus containing 16 species that are sporadically collected in low densities all over the world oceans. During three cruises (in June 2014 in Ullsfjorden, northern Norway, in January 2015 in Kongsfjorden, and in June 2012 in Smeerenburg, Svalbard) nine specimens of Lacydonia eliasoni were found on sandy and muddy sediments at depths from 180 to 350 m. All specimens were incomplete and consisted of 10 to 29 chaetigers. This study presents the first record of the Lacydonia genus in the waters of Svalbard as well as the first record of L. eliasoni in coastal waters off northern Norway. This species has been reported previously in the Skagerrak and Trondheimsfjorden (southern Norway), our findings therefore may indicate a northward extension of its range, possibly due to climate changes.
The eight most abundant species (mean density >20 ind. m −2 ), which occurred at high frequencies (mean >30%) were selected from grab samples in the three Svalbard fjords: Hornsund, van Mijenfjord, and Kongsfjord, in the summer seasons between 1997 and 2007. Six polychaete and two bivalve species comprised more than 47% of the individuals and the biomass in all the samples examined. Four species are cosmopolitan, while the others are widely distributed Arctic−boreal species, and none has Arctic origin. Their density, frequency of occurrence, and biology are very similar across the wide geographical range from boreal to Arctic conditions. As the diversity of benthic fauna in the fjords studied increases (from 172 to 238 species), the dominance of the eight species in the soft bottom community diminishes from 76% to 47%. In times of hydrological regime shift, i.e. , the warming of the European Arctic, it is unlikely that the abundancy of these species in the soft bottom fjordic ecosystems will change. The most common soft bottom species are not good indicators of environmental change in the Arctic, and rare, specialized species are better option for indicative purposes.
Thirty-two species of echinoderms from epibenthic sledges, dredges, scuba diving, and other samples (in total: 467 samples and c. 20 000 specimens) from fjords and coastal waters off Spitsbergen were analysed between 1996 and 2014. The most numerous group of echinoderms in the coastal waters off Spitsbergen is brittle stars (78% of the total individuals). The echinoderms do not form any clear assemblages according to depth or distance from glacial sedimentation and substrate. Some species prefer hard bottom (Strongylocentrotus droebachiensis) or water free from glacial suspensions (Ophiopholis aculeata). In contrast to the species listed above, we also found opportunistic species such as the starfish Urasterias lincki and the brittle star Ophiocten sericeum. These two species are distributed quite uniformly, regardless of the environmental factors. The majority of the species prefer a soft bottom below 200 m.
Hornsund, an Arctic fjord in the west coast of Spitsbergen (Svalbard), was selected as All Taxa Biodiversity Inventory (ATBI) site under EU 5th Framework Concerted Action BIOMARE (2000–2002), especially due to its pristine, undisturbed natural character. On the base of large material (89 stations located throughout the fjord and 129 Van Veen grab samples) collected during cruises of RV Oceania in July in 2002, 2003, 2005 and 2007 and literature search a comprehensive list of species recorded within Hornsund area, on the soft bottom with depth range of 30–250 m is provided. Over 220 species were identified including 93 species of Polychaeta, 62 species of Mollusca and 58 species of Crustacea. Species list is supported by information on the zoogeographical status, body length and biological traits of dominant species. Need for further research on Hornsund soft bottom fauna with more sampling effort is highlighted.
The total numbers and biomass of bacterioplankton in two Arctic glacial fjords off west Spitsbergen were studied. Samples were collected from different water depth layers – from the surface to 80–90 m depth. Total bacterial number (TBN), biomass and morphological structure (shape of bacteria) were determined using the acridine orange direct count method. The highest values of TBN and biomass in the water column were found in Kongsfjorden in the stations adjacent to Kongsbreen Glacier, and the lowest values in the outer part of the Krossfjorden. The local maxima of bacterioplankton were observed in water layers around pycnocline. The morphological structure was similar in all samples – the bacteria were dominated by rods (over 65%), followed by cocci (16–20%) and vibrios (11–15%).
The shallow water benthic fauna was collected in Kongsfjord, West Spitsbergen. Sampling was conducted along two main environmental gradients: vertical gradient (depth 5–50 m) and horizontal gradient (sedimentation regime) along the fjord axis. A small rectangular dredge was used. Altogether 169 taxa were identified and four macrofaunal associations were distinguished. Bottom type and distance from the tidal glaciers seem to be the main factors responsible for species distribution. The Soft Bottom I Association occupying the fine mud of the Kongsbreen glacial bay consisted mostly of Crustacea with high dominance of scavenging amphipod Onisimus caricus. Bivalves prevailed in the Soft Bottom II Association, located further away from the main glacier outflows. The barren rocky shelf, deprived of vegetation by a sea urchin Strongylocentrotus droebachiensis was inhabited by the Rocky Shelf Association dominated by decapods. The last distinguished association (the Kelp Association) occurred on the hard bottom overgrown with macroalgae. The gastropod Margarites helicinus and amphipods Ischyrocerus spp. made up 60% of the individuals collected there.
Soft bottom fauna have been sampled along the Spitsbergen fjord depression entering shelf, slope and Greenland Sea Ocean Basin at 200, 300, 500, 1500, 2000 and 3000 m depths. From 19 samples covering 1.9 m2, 4295 individuals of 194 macrofauna species have been sorted. Density decreased markedly from over 6000 ind/m2 in shelf stations to some 600 ind/m2 below 1500 m depth. Only two taxa (Chaetozone group and Lumbrineris sp. A) occurred in more than 75% of samples, 55 taxa (28% of the total) were represented by single specimens only. The highest number of species per sample (65 taxa in 0.1 m2) was noted at 525 depth. There were 14 eurybathic species and the same number of taxa were found exclusively below 2000 m depth, while 117 species were found only shallower than 300 m depth.