Slawomir Kwasniewski

The Institute of Oceanology of the Polish Academy of Sciences · Department of Marine Ecology

Zooplankton consumption of sinking aggregates affects the quality and quantity of organic carbon exported to the deep ocean. Increasing laboratory evidence shows that small particle‐associated copepods impact the flux attenuation by feeding on sinking particles, but this has not been quantified in situ. We investigated the impact of an abundant par...

The reduction of Arctic summer sea ice due to climate change can lead to increased primary production in parts of the Barents Sea if sufficient nutrients are available. Changes in the timing and magnitude of primary production may have cascading consequences for the zooplankton community and ultimately for higher trophic levels. In Arctic food webs...

With climate warming, many tidewater glaciers are retreating. Fresh, sediment-rich sub-glacial meltwater is discharged at the glacier grounding line, where it mixes with deep marine water resulting in an upwelling of a plume visible in front of the glacial wall. Zooplankton may suffer increased mortality within the plume due to osmotic shock when b...

The climate affects aquatic ecosystems worldwide, yet the most dramatic impact has been observed in Polar Regions. The presented study aimed to test the hypothesis that changes in biodiversity are linked to changes in the food web functioning under different temperature conditions, with large species dominant in cold waters and smaller species domi...

Oceanic fronts constitute boundaries between hydrologically distinct water masses and comprise one of the most productive regions of the world’s ocean. Fronts associated with density gradients (active fronts) profoundly structure planktonic communities in adjacent waters, but less is known about the impacts of density-compensated (passive) fronts....

Increasing heat content, salinity, and velocity of the Atlantic water masses passing northward through the Fram Strait accelerate the transition of the European Arctic toward more Atlantic state, a process referred to as Atlantification. A pronounced environmental shift leads to a poleward expansion of boreal species ranges and alters seasonal rhyt...

The traditional view is that the Arctic polar night is a quiescent period for marine life, but recent reports of high levels of feeding and reproduction in both pelagic and benthic taxa have challenged this. We examined the zooplankton community present in Svalbard fjords, coastal waters, and the shelf break north of Svalbard, during the polar nigh...

Supplementary table for the article Barth-Jensen et al. (2022). High abundances of small copepods early developmental stages and nauplii strengthen the perception of a non-dormant Arctic winter. Polar Biology

Instytut Oceanologii Polskiej Akademii Nauk przechowuje 77500 okazów przyrodniczych z obszarów morskich, gromadzonych od 1985 r., czyli od początku istnienia Pracowni Ekosystemów Arktyki, przekształconej później w Zakład Ekologii Morza. Większość zbiorów stanowi zooplankton (około 36000 okazów) zebrany podczas corocznych rejsów badawczych statku s/...

The impact of the rapidly changing Arctic on zooplankton community structure and seasonal behaviour is not yet understood. Here we examine 6 months of under-ice zooplankton observations from the N-ICE2015 expedition (January to June 2015) in the Nansen Basin and on the Yermak Plateau north of Svalbard. Stratified sampling in the water column was do...

Current climate change is significantly modifying Arctic ecosystems and their components, but the reference and direction of these changes are still undefined. The aim of this study was to provide well-grounded data on the present composition and structure of zooplankton from boreal to Arctic latitudes. This comparative study was performed with a u...

The Arctic Ocean is changing rapidly with respect to ice cover extent and volume, growth season duration and biological production. Zooplankton are important components in the arctic marine food web, and tightly coupled to the strong seasonality in primary production. In this study, we investigate zooplankton composition, including microzooplankton...

Zooplankton in Kongsfjorden, Svalbard, is shaped by irregular advection of seawater from the West Spitsbergen Current as well as input of freshwater of glacial and riverine origin. The zooplankton community reflects contributions of Arctic vs. Atlantic water masses in the fjord, and is changing with increasing tem- perature and declining sea ice. H...

Marine ecosystems in Arctic regions are expected to undergo large changes, driven by sea ice retreat and increasing influence of warmer and saline waters. We examined changes in the hydrography and mesozooplankton from a 14-year long time series in the West Spitsbergen Current during the summer period. The aim was to provide a contemporary descript...

The northern coast of Svalbard contains high-arctic fjords, such as Rijpfjorden (80°N 22°30′E). This area has experienced higher sea and air temperatures and less sea ice in recent years, and models predict increasing temperatures in this region. Part of the West Spitsbergen Current (WSC), which transports relatively warm Atlantic water along the c...

The largest contribution of oceanic heat to the Arctic Ocean is the warm Atlantic Water (AW) inflow through the deep Fram Strait. The AW current also carries Atlantic plankton into the Arctic Basin and this inflow of zooplankton biomass through the Atlantic-Arctic gateway far exceeds the inflow through the shallow Pacific-Arctic gateway. However, b...

The advection of warm Atlantic water into the Arctic influences not only the thermal and sea ice conditions in the Arctic Ocean and the adjacent seas but also the Arctic marine biota. Earlier efforts to characterize the response of zooplankton communities to the increasing influence of warm AW were focused mostly on changes in taxonomic diversity a...

The advection of warm Atlantic water into the Arctic influences not only the thermal and sea ice conditions in the Arctic Ocean and the adjacent seas but also the Arctic marine biota. Earlier efforts to characterize the response of zooplankton communities to the increasing influence of warm AW were focused mostly on changes in taxonomic diversity a...

Copepods of the genus Calanus play a key role in marine food webs as consumers of primary producers and as prey for many commercially important marine species. Within the genus, Calanus glacialis and Calanus finmarchicus are considered indicator species for Arctic and Atlantic waters, respectively, and changes in their distributions are frequently...

Planktonic copepods of the genus Calanus play a central role in North Atlantic/Arctic marine food webs. Here, using molecular markers, we redrew the distributional ranges of Calanus species inhabiting the North Atlantic and Arctic Oceans and revealed much wider and more broadly overlapping distributions than previously described. The Arctic shelf s...

Recent observations confirm the rising temperatures of Atlantic waters transported into the Arctic Ocean via the West Spitsbergen Current (WSC). We studied the overall abundance and population structure of the North Atlantic keystone zooplankton copepod Calanus finmarchicus, which is the main prey for pelagic fish and some seabirds, in relation to...

Zooplankton inhabiting the Hornsund and Kongsfjorden fjords on Spitsbergen (Svalbard) were investigated in summer 2013. The goal of the study was to determine how the zooplankton communities vary in environments functioning under different oceanographic regimes. Sampling was conducted with nets of different mesh size and selectivity (56μm WP-2, 180...

Two high latitude fjords of Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N) are regarded as being highly productive (70g and 50gCm⁻²year⁻¹) and having organic-rich sediments. Hornsund has more organic matter in its sediments (8%), nearly half of it of terrestrial origin, while most of that in Kongsfjorden (5%) comes from fresh, marine sources (mi...

Atlantic water (AW) carries large amounts of salt, oceanic heat, and biological richness into the Arctic Ocean. The inflow of AW has a two-branch structure via the West Spitsbergen Current (WSC) in the Fram Strait and the Barents Sea Opening (BSO), and the impact of AW on the Arctic Ocean ecosystem depends on the entrance route. Using data collecte...

A multi-scale approach was used to evaluate which spatial gradient of environmental variability is the most important in structuring zooplankton diversity in the West Spitsbergen Current (WSC). The WSC is the main conveyor of warm and biologically rich Atlantic water to the Arctic Ocean through the Fram Strait. The data set included 85 stratified v...

Three-factor PERMANOVA results for the zooplankton descriptor sets and 999 permutations. LAT – latitudinal section; LON – longitudinal region; WL – water layer; df – degrees of freedom; MS – means of squares; √ECV – square root of estimated components of variance; %ECV – percentage of ECV to total variation. Bold values indicate p<0.05. (DOCX)

Two- and three-factor PERMANOVA results for the environmental descriptor sets and 999 permutations. LAT – latitudinal section; LON – longitudinal region; WL – water layer; df – degrees of freedom; MS – means of squares; √ECV – square root of estimated components of variance; %ECV – percentage of ECV to total variation. Bold values denote significan...

Information on sample collection, July 2012. LAT – latitudinal sections; LON – longitudinal regions; WL – water layer extent. (DOCX)

Results of the DistLM procedure for fitting hydrographic variables, chlorophyll a concentration and biomass of dominant protist taxa to the zooplankton community (model 0–50 m only herbivorous species). Var%—percentage of explained variance; Cum%—cumulative percentage explained by the added variable. Bold values denote significance at p<0.05. (DOCX...

The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms b...

Plankton patchiness, a widely known but poorly studied phenomenon, was investigated concurrently with measurements of environmental conditions in the Polar Front region west of Spitsbergen in summer (June-July) 2012. Continuous high-resolution observations were made using a laser optical plankton counter, a fluorometer and CTD along several section...

Zooplankton abundance and community structures were studied in three west Spitsbergen fjords at the beginning of the warm phase, which seem to have entered in 2006. Sampling was conducted in summer 2007 at stations distributed along transects in Hornsund, Isfjorden and Kongsfjorden. Variations in zooplankton standing stocks and community structures...

This paper presents information on diet and distribution of larval snailfishes from the genus Liparis on the Canadian Beaufort Sea Shelf. In this study, 153 larval snailfishes of three species, Liparis fabricii, L. gibbus and L. tunicatus, were collected during 4 summer cruises (2003–2005, 2007). The majority of the larvae were either in flexion or...

Several decades of research on invasive marine species have yielded a broad understanding of the nature of species invasion mechanisms and associated threats globally. However, this is not true of the Arctic, a region where ongoing climatic changes may promote species invasion. Here, we evaluated risks associated with non‐indigenous propagule loads...

The pelagic copepods Calanus glacialis and C. finmarchicus are important components of Arctic marine ecosystems. Projected climate warming may influence the roles they play in the ecosystem. Arctic C. glacialis and boreal C. finmarchicus eggs were incubated at temperatures of 0, 2.5, 5, 7.5 and 108C to investigate the effects of increasing temperat...

The complete diet composition structure of the most numerous planktivorous sea bird, little auk (Alle alle), in the European Arctic, is still not fully recognized. Although regular constituents of little auk chick diets, the copepods, Calanus glacialis and C. finmarchicus have been previously relatively well described, more taxa were fre-quent ingr...

Diel vertical migration (DVM) of zooplankton is a global phenomenon, characteristic of both marine and limnic environments. At high latitudes, patterns of DVM have been documented, but rather little knowledge exists regarding which species perform this ecologically important behaviour. Also, in the Arctic, the vertically migrating components of the...

We studied summer mesozooplankton composition between 2001 and 2009, in the epipelagic zone of the West Spitsbergen Current (WSC) and adjacent areas, which constitute a transition zone between warmer Atlantic and cold Arctic waters. According to hydrography and species composition this region could be divided into four main areas: western and easte...

One of the main challenges in contemporary biological oceanography is to understand the factors that drive the spatial heterogeneity of pelagic organisms. Our study was performed at 10-m depth intervals within the upper 50 m of the ocean, at two different localities on the West Spitsbergen Shelf in the summers of 2009 and 2010. The fine-scale patte...

This paper contributes to baseline knowledge of lower trophic levels that is necessary to monitor the impact of oil and gas development on the Canadian Beaufort Sea ecosystem. As part of the Nahidik Program, the vertical distribution of mesozooplankton was studied along two transects in the coastal Canadian Beaufort Sea in the summer of 2009. Mesoz...

Seasonal mesozooplankton community composition was studied monthly from March to October 2007 in the high Arctic, Rijpfjorden (Svalbard), and related to abiotic (hydrography, sea ice) and biotic (ice algae and phytoplankton biomass) environmental conditions. The community was numerically dominated by the cosmopolitan Oithona similis, whereas Arctic...

The timing of zooplankton reproduction in relation to spring pelagic bloom is essential in determining grazers' recruitment success and the transport of biomass through the system. At high latitudes marine ecosystems are characterized by extreme seasonality with the production of autotrophes concentrated during the spring. In two consecutive years...

Bowhead whales (Balaena mysticetus) of the Bering-Chukchi-Beaufort population form annual late-summer feeding aggregations offshore of the eastern Tuktoyaktuk Peninsula and Cape Bathurst. This region is strongly influenced by episodic upwelling events. A systematic aerial survey (10% coverage) was flown over the eastern shelf on 2 August 2008, reve...

The biomass of Calanus spp. in the Norwegian Atlantic Current and the West Spitsbergen Current (2001–2009) was statistically related to a combination of salinity, temperature, water depth and sea ice concentration. The aim of this study was to identify the significance of these environmental factors for controlling the species-specific biomass dist...

The Arctic Ocean is facing rapid changes in seawater carbonate chemistry due to the uptake of atmospheric carbon dioxide (CO 2). In the current study, the effects of different seawater pH levels (8.2, 7.6 and 6.9) on the reproduction of Calanus glacialis, an Arctic shelf-water copepod, have been quantified. Results indicated that CO 2 -induced seaw...

Kwasniewski, S., Gluchowska, M., Walkusz, W., Karnovsky, N. J., Jakubas, D., Wojczulanis-Jakubas, K., Harding, A. M. A., Goszczko, I., Cisek, M., Beszczynska-Möller, A., Walczowski, W., Weslawski, J. M., and Stempniewicz, L. 2012. Interannual changes in zooplankton on the West Spitsbergen Shelf in relation to hydrography and their consequences for...

The Atlantic sector of the Arctic is undergoing widespread climate change with increases in air and sea temperatures which impact the timing of ice retreat, snow melt and the development of the marine food web. Dovekies (Alle alle) are small seabirds that migrate to the Atlantic Sector of the Arctic to feed in ice free waters that have abundant lip...

In conditions of deteriorating food availability, seabirds may maximize their breeding success by increasing reproductive effort, which compromises body condition, stress level, survival, and future reproductive success. We studied a small planktivorous alcid, the little auk Alle alle, in 2 breeding colonies in west Spitsbergen, Norway (Hornsund an...

We followed the fatty acid composition of particulate organic matter (POM) in a High Arctic fjord (79°N; Svalbard, Norway) during and after the spring bloom. The content of essential polyunsaturated fatty acids (PUFAs) was highest (45% of total fatty acids) at the beginning of the bloom, well before the biomass maximum, and decreased linearly towar...

The distribution and diet of larval and juvenile Arctic cod (Boreogadus saida) were studied during summer 2005 in the coastal Canadian Beaufort Sea. A total of 275 individuals were captured and the highest abundance was observed at station depths of 20-30 m. This corresponds well with the location of the frontal zone where the Mackenzie River plume...

a b s t r a c t Composition and abundance of zooplankton were studied simultaneously with feeding ecology of plank-tivorous Little Auks (Alle alle) in two different sea shelf areas of West Spitsbergen, Norway, in summer 2007. Zooplankton was collected adjacent to bird colonies in Magdalenefjorden (influenced by Atlantic West Spitsbergen Current) an...

The Arctic is undergoing widespread warming. In order to understand the impact of climate change on Arctic marine food webs, we studied the at-sea distribution of foraging little auks in contrasting conditions of the Greenland Sea. While the eastern side of the Greenland Sea has experienced recent warming, the western side is still dominated by col...

Seasonal changes in the zooplankton composition of the glacially influenced Kongsfjorden, Svalbard (79°N, 12°E), and its adjacent shelf were studied in 2002. Samples were collected in the spring, summer and autumn in stratified hauls (according to hydrographic characteristics), by means of a 0.180-mm Multi Plankton Sampler. A strong front between t...