Marek Zajaczkowski

The physical environment of Kongsfjorden–Krossfjorden, an Arctic fjord system in Svalbard

Kongsfjorden-Krossfjorden and the adjacent West Spitsbergen Shelf meet at the common mouth of the two fjord arms. This paper presents our most up-to-date information about the physical environment of this fjord system and identifies important gaps in knowledge. Particular attention is given to the steep physical gradients along the main fjord axis, as well as to seasonal environmental changes. Physical processes on different scales control the large-scale circulation and small-scale (irreversible) mixing of water and its constituents. It is shown that, in addition to the tide, run-off (glacier ablation, snowmelt, summer rainfall and ice calving) and local winds are the main driving forces acting on the upper water masses in the fjord system. The tide is dominated by the semi-diurnal component and the freshwater supply shows a marked seasonal variation pattern and also varies interannually. The wind conditions are characterized by prevailing katabatic winds, which at times are strengthened by the geostrophic wind field over Svalbard. Rotational dynamics have a considerable influence on the circulation patterns within the fjord system and give rise to a strong interaction between the fjord arms. Such dynamics are also the main reason why variations in the shelf water density field, caused by remote forces (tide and coastal winds), propagate as a Kelvin wave into the fjord system. This exchange affects mainly the intermediate and deep water, which is also affected by vertical convection processes driven by cooling of the surface and brine release during ice formation in the inner reaches of the fjord arms. Further aspects covered by this paper include the geological and geomorphological characteristics of the Kongsfjorden area, climate and meteorology, the influence of glaciers, freshwater supply, sea ice conditions, sedimentation processes as well as underwater radiation conditions. The fjord system is assumed to be vulnerable to possible climate changes, and thus is very suitable as a site for the demonstration and investigation of phenomena related to climate change.

Intertidal zone of svalbard

SummaryIn summer 1985–1991, the intertidal zone of the Svalbard archipelago was sampled in 242 localities. Thirty seven laxa of macrofauna and 22 of macrophytes were considered as littoral zone inhabitants. Four major littoral assemblages are described: Fucus-Balanus, Gammarus, Onisimus and Oligochaeta communities. More than 80% of the investigated coast is occupied by the Oligochaeta assemblage with mean biomass values less than 1 kJ/m2. The richest benthos was found at Fucus-Balanus sites (8% of the coast line) with biomass values exceeding 2000 kJ/m2. The southern tip of Spitsbergen is part of a major zoogeographical border in the littoral fauna distribution. Subarctic species like barnacles, periwinkles and Gammarus oceanieus predominate on the western coast whereas, on the Arctic East coast barren beaches, G. setosus predomination was found.

Distribution of meiofauna in Kongsfjorden, Spitsbergen

Kongsfjorden, a glacial fjord, is a typical fjord in the Spitsbergen (Svalbard archipelago) in the Arctic. The study supports a hypothesis that meiofauna and macrofauna are affected by natural environmental disturbances. Therefore, meiofaunal and macrofaunal analyses can be used to assess the effects of natural environmental disturbances in similar fjords in the Spitsbergen. Inputs from tidal glaciers create steep environmental gradients in sedimentation and salinity along the fjord. The magnitude of the glacial outflow diminishes towards the outer part of the fjord. Glacial-related physical stress causes reduced abundance, biomass and diversity among the meiofaunal assemblages in the inner part of the fjord. Based on quantitative and qualitative analyses of the composition of collected samples, three groups of meiofauna have been distinguished: one outer basin association and two in the inner, glacial bay. The presented results demonstrate that both the meiofauna and the macrofauna are affected on a similar scale by natural environmental disturbances. Therefore, as for macrofauna, meiofaunal analysis can be used to assess the effect of natural environmental disturbances.

Seasonality of occurrence and recruitment of Arctic marine benthic invertebrate larvae in relation to environmental variables

The Arctic system is one of the regions most influenced by ongoing global climate change, but there are still critical gaps in our knowledge regarding a substantial number of biological processes. This is especially true for processes taking place during the Arctic winter but also for seasonal processes, such as the dynamics of intra-annual meroplankton occurrence. Here, we report on a 1-year study of meroplankton seasonal variability from a fjordic system in the Arctic Archipelago of Svalbard. The study combines an examination of phytoplankton, zooplankton, and hard bottom benthic settlement with measurements of environmental parameters (e.g., water temperature, particulate organic matter, and dissolved organic carbon). Samples were taken on a bi-weekly or monthly basis, and a total of 11 taxa representing six phyla of meroplankton were recorded over a 1-year period from January to December 2007. The occurrence of benthic larvae varied between the seasons, reaching a maximum in both abundance and taxon richness in late spring through early summer. Meroplanktonic larvae were absent in winter. However, settlement of benthic organisms was also recorded during the winter months (February and March), which indicates individual trade-offs related to timing of reproduction and competition. In addition, it suggests that these larvae are not relying on higher summer nutrient concentrations, but instead are dependent on alternative food sources. In parallel with meroplankton abundance, all other measured parameters, both biological (e.g., phyto- and zooplankton abundance and diversity) and physical (e.g., particulate organic matter), exhibited seasonal variability with peaks in the warmer months of the year.

The coastal edge of the Northeast Water polynya in spring 1993

Multidisciplinary, marine ecological observations were conducted at the shallow water edge of the Northeast Water in June, 1993. Although variable in size and shape, a small polynya was constantly present at Eskimonaes, at the fast-ice edge of Ingolfsfjord. A shallow stratified layer developed at the water sufface at negative water and air temperatures—an effect of sea ice melting in cold water early in the season. Nutrients were recorded in considerable quantities, although by mid July NO3 had become depleted. The chlorophyll and phytoplankton maxima at 8–12 m depth had peak values of 2 mg chl a m−3, typical for Arctic algal blooms. The phytoplankton included over 90 species and was dominated by the Fragillariopsis group. Zooplankton was poor in biomass and density, but over 23 taxa were found, with the copepods Oithona similis and Pseudocalanus acuspes being numerically dominant. Sedimentation was approximately 0.2 g dry weight m−2 d−1 and suspended matter concentrations ranged from 4 to 19 mg l−1. The benthos was represented by hard bottom forms only, with a surprisingly dense cover of macrophytes. Juvenile sea urchins (Strongylocentrotus droebachiensis), brittle stars (Ophiocten sericeum) and amphipods were dominant. Higher trophic levels were represented by benthic feeders, such as eiders and walruses. The area observed was more similar to high Arctic fjord ecosystems than to the offshore central Northeast Water polynya.