Search

This publication presents a possibly never-before-recorded new behaviour, adaptations of the filter feeder crinoid using Hyas crabs in the inner, heavily loaded with suspension runoff part of the Spitsbergen fjords. The work used a 16-hour and 45-minute time-lapse sequence showing the decompositions of Atlantic Cod. During the exposure, apart from typical organisms such as carrion crustaceans, crabs and starfish, several individuals of crinoids were observed. One of the crinoids attached its cirri to the edge of the platform for most of the exposure. The remaining individuals observed attached to the carapace of Hyas crabs for 6 hours 55 minutes. It was also found, basis on analysis of the video material from 202 locations examined in the summer season between 2015-2020 using a drop camera, additionally two locations with a positive occurrence of a comatulida. Both locations in the Ekmanfjorden and in the interior of the Vanmijenfjorden are areas under the strong influence of a glacier or a glacial river. So far, the occurrence of crinoids has been found mainly in locations outside of the influence of turbid waters from fjords. We believe that the new observation of the comatulida behaviour will allow it to colonize new regions gradually exposed by the retreating glaciers.

The Institute of Oceanology of the Polish Academy of Sciences (IO PAN) stores 77,500 natural history specimens from marine areas, which have been collected since 1985, when the Arctic Ecosystem Laboratory was established, later transformed into the Department of Marine Ecology. The majority of the collection is zooplankton (approximately 36,000 specimens) collected during the annual research cruises with the s/y Oceania ship to the area of the Nordic seas. Some smaller collections organized by individual researchers working with specific systematic groups are equally important. Thus, the Institutes collection resources also include specimens of bryozoans (Bryozoa), crustaceans (Crustacea) with a separate collection of hermit crabs (Paguroidea), as well as hydroids (Hydrozoa), bristle worms (Polychaeta), molluscs (Mollusca), sipunculid worms or peanut worms (Sipuncula), and echinoderms (Echinodermata) as well as protists (Protista), meiofauna with separate collections of kinorhynchs, the spiny-crown worms (Kinorhyncha) and nematodes (Nematoda) as well as Antarctic and Gulf of Gdansk macrofauna. As part of the IMBIO project (Integration and mobilization of data on the biotic diversity of Eukaryota in the resources of Polish scientific institutions), the specimen collections currently held by the Institute will be systematized and organized, and the data on resources will be digitalized in the form of metadata databases. The idea of digitizing the data contained in the descriptions of scientific collections and sharing them through the Polish Biodiversity Information Network (KSIB) and the Global Biodiversity Information Facility (GBIF) organizations will facilitate a wider insight and use of previously unavailable scientific collections.

This study couples observations of krill (Thysanoessa inermis, Thysanoessa longicaudata, Thysanoessa rashii) from Tucker trawl nets and cameras, trying to test hypothesis that in the glaciated fjords of Svalbard most of the euphausiids biomass is located in near-bottom habitat and explains why in this region there are a substantial part of the krill population near the sea floor. Photographic material from the summers of 2013–2017 shows large numbers of near-bottom euphausiids (39% of the total krill biomass in Hornsund and 41% in Kongsfjorden), which reached a maximum density of 751 ± 224 indiv. m−3 in Kongsfjorden, 731 ± 198 indiv. m−3 in Hornsund, and 426 ± 124 indiv. m−3 in Adventfjorden. Regional distribution of near-bottom aggregations of krill seem to be associated with close proximity to the glacier front rather than with depth. The highest densities were located in the glacial bays. Where and why these aggregations occur is probably complicated and dependent on many environmental factors acting together. However, the dominant factors seem to be sedimentation and estuarine circulation. No krill aggregations were found during the winter cruise. The dominating species was T. inermis which made up 90% of the community. Other krill species—T. rashii and T. longicaudata, made up 6% and 4%, respectively. In the summer, aggregations of other macrozooplankton were also observed: amphipods of the genus Themisto and chaetognaths of the genera Eukrohnia and Parasagitta. Euphausiid densities in the water column (from Tucker trawl hauls) were an order of magnitude lower (0.33 indiv. m−3 for Kongsfjorden and 0.61 indiv. m−3 for Hornsund) than those of the near-bottom aggregations observed on cameras system. At most stations, the krill exhibited a behaviour, known as “nose diving” in the sediment, which is likely related to feeding. Observation of this phenomenon may indicate that krill (mostly T. inermis), found near the bottom of Spitsbergen fjords, is looking for food there. Near-bottom aggregations of zooplankton, mainly krill, are common in glacial bays and can be important in the function of the fjord ecosystem. Our research proves that the zooplankton biomass can be highly underestimated if only Tucker trawl sampling is done, due to neglecting the near-bottom layer in this type of method.

Climate-induced glacial retreat in the Arctic results in an increased supply of meltwater with suspended terrigenous material into the marine environment. Despite increasing research efforts, effects of glacial retreat on functioning of plankton are not well documented and understood. Thus, we studied a hydro-optical seawater regime along with particle/plankton concentrations and composition structure in a high Arctic fjord (Isfjorden, West Spitsbergen) during mid-summer in 2019. This comprehensive study of the upper 50 m water layer presented a sharp distinction between ‘muddy’ waters influenced by glacial and river runoff and ‘clear’ open fjordic waters in the form of a notable difference in chlorophyll a concentrations, extent of euphotic zone depth, turbidity, inorganic/organic particle concentrations, and water colour. In this study, we present that the effects of glacial retreat on Arctic pelagial depend not only on different types of glaciers (marine- and land-terminating), but presumably, also on fjord topography and exposure to oceanic water inflow. The contrasting glacial, hydrological, and topographical conditions had different effects on the share of zooplankton and marine snow. Despite adaptation of the planktonic communities in the Arctic to high sediment loads and resultant light limitations, our study shows that continuing retreat of tidewater glaciers will have negative effect on planktonic communities especially in enclosed shallow fjord branches. Moreover, seawater darkening due to high turbidity could negatively affect tactile predators, such as gelatinous zooplankton. Additional division of plankton into functional groups typically used in the biogeochemical models demonstrated that diatoms, flagellates and mesozooplankton are influenced by suspended matter, whereas microzooplankton are highly adaptive to increased sediment loads. Since we investigated the largest Svalbard fjord system and incorporated multiple components of the pelagic realm, the current study delivers important recommendations for including marine snow and gelatinous zooplankton in ecosystem models applied in polar regions.

Mature ecosystems sequester little organic carbon (C org ) in sediments, as the complex and effective food webs consume most available organic matter within the water column and sediment, in contrast to young systems, where a large proportion of C org is buried in deeper sediment layers. In this paper we hypothesize that “warmer” Atlantic water influenced fjord exhibits the ‘mature’ system features as compared to “cooler” Arctic water influenced fjord. C org concentrations, sources and burial rates, as well as macrobenthic community standing stocks, taxonomic and functional composition and carbon demand, were compared in two west Spitsbergen fjords that are to different extents influenced by Atlantic water and can be treated as representing a cold one (Hornsund) and a warm one (Kongsfjorden). Water, sediments and macrofauna were collected at three stations in the central basin of each fjord. C org , N tot , δ 13 C org and δ 15 N were measured in suspended matter, sediment cores and possible organic matter sources. The composition of sources of sedimentary organic matter was modeled by Mix-SIAR Bayesian stable isotope mixing models. The 210 Pb method was used to calculate sediment accumulation rates, C org accumulation and burial rates. The sedimentary C org concentration and accumulation rate were larger in Hornsund than in Kongsfjorden. The contributions of pelagic sources to the C org in sediments were similar in both fjords, macroalgal detritus had a higher importance in Kongsfjorden, while terrestrial sources were more important in Hornsund. Similar density and species richness were noted in both fjords, but higher biomass, individual biomass, production and carbon demand of benthic communities were noted in Kongsfjorden despite the lower amounts of C org in sediments, indicating that macrobenthos responds to quality rather than quantity of available food. Subsurface tube-building conveyer belt detritus feeders (maldanids and oweniids) were responsible for higher standing stocks and carbon consumption in Kongsfjorden. As a result of the lower C org pool and higher benthic mineralization, the burial rates in Kongsfjorden were much lower (15 g of C org m − 2 yr − 1 ) than in Hornsund (38 g of C org m − 2 yr − 1 ). Our study indicates that warming of the high latitude fjordic environments may reshape the relative proportions of organic carbon sources and induce maturing of the sea bottom systems, in terms of development of stable, biologically accommodated benthic communities which more efficiently mineralize organic matter and consequently lower sequestration of organic matter in deeper sediments.

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.

Three species of dexaminid amphipods are currently known from the Arctic, but none of them have been hitherto recorded in the west Spitsbergen fjords (Svalbard). In 2010, four individuals of dexaminidGuernea (Prinassus) nordenskioldiwere sampled for the first time in the mouth of Isfjorden, a large fjord system located at 78°N. The species was originally described by Hansen (1888) from West Greenland and since then it has been collected in a number of locations showing almost circumarctic distribution. This study represents the first record of the family Dexaminidae and the speciesG. (P.) nordenskioldifrom west Spitsbergen (Greenland Sea).

WOS:000390030500014; International audience; This study explores whether the marked seasonality in pelagic productivity and phytodetritus fluxes to the sea bottom in an Arctic fjord is reflected in variability of benthic communities in terms of taxonomic composition and standing stocks. Three stations located along the Kongsfjorden (west Spitsbergen) axis were visited in four seasons (May, August, October and January), and meiofauna and macrofauna was sampled. The elusive seasonal variability in benthic attributes contrasted with the clear seasonal effects in organic matter productivity and vertical fluxes (with diatom bloom-related peak in spring). No consistent differences in meiofaunal and macrofaunal density, diversity or composition among the four seasons were detected by PERMANOVA tests. Possible responses to spring food supply in meiofaunal reproduction timing were demonstrated in variability in individual size of Nematoda (decline in October after the maximum in August), Harpacticoida (decline in May and increase till October) and macrobenthic Crustacea (minimum in May). The spatial patterns shaped by the environmental gradients related to glacial inputs, the faunal impoverishment in inner basin and a shift in dominants along the fjord axis, were clearly designated and stable throughout the year. The resilience of Arctic fjordic benthic community to marked seasonality in pelagic phytodetritus fluxes may be related to organic matter reserves in sediments (large enough to sustain the detritus feeders on a year-round basis), inclusion of macroalgal carbon into the diet and common employment of lecithotrophic larva or direct development by polar benthos.