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The malacostracan fauna of two Arctic fjords (west Spitsbergen) : the diversity and distribution patterns of its pelagic and benthic components

Legeżyńska J., Włodarska-Kowalczuk M., Głuchowska M., Ormańczyk M., Kędra M., Węsławski J. M.

Oceanologia

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2017

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No. 59 (4)

541--564

EN

This study examines the performance of pelagic and benthic Malacostraca in two glacial fjords of west Spitsbergen: Kongsfjorden, strongly influenced by warm Atlantic waters, and Hornsund which, because of the strong impact of the cold Sørkapp Current, has more of an Arctic character. The material was collected during 12 summer expeditions organized from 1997 to 2013. In all, 24 pelagic and 116 benthic taxa were recorded, most of them widely distributed Arctic-boreal species. The advection of different water masses from the shelf had a direct impact on the structure of the pelagic Malacostraca communities, resulting in the clear dominance of the sub-arctic hyperiid amphipod Themisto abyssorum in Kongsfjorden and the great abundance of Decapoda larvae in Hornsund. The taxonomic, functional and size compositions of the benthic malacostracan assemblages varied between the two fjords, and also between the glacier-proximate inner bays and the main fjord basins, as a result of the varying dominance patterns of the same assemblage of species. There was a significant drop in species richness in the strongly disturbed glacial bays of both fjords, but only in Hornsund was this accompanied by a significant decrease in density and diversity, probably due to greater isolation and poorer quality of sediment organic matter in its innermost basin. Our results suggest that the diversity and distribution of benthic malacostracans in these two fjords are only distantly related to the different hydrological regimes; rather, they are governed by locally acting factors, such as depth, sediment type, the variety of microhabitats and the availability and quality of food.

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Can seabirds modify carbon burial in fjords?

Węsławski J. M., Urbański J., Głuchowska M., Grzelak K., Kotwicki L., Kwaśniewski S., Legeżyńska J., Wiktor J., Włodarska-Kowalczuk M., Zaborska A., Zajączkowski M., Stempniewicz L.

Oceanologia

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2017

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No. 59 (4)

603--611

EN

Two high latitude fjords of Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N) are regarded as being highly productive (70 g and 50 gC m−2 year−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 (microplankton). Analysis of the carbon sources in both fjords shows that a major difference is the much larger seabird population in Hornsund-dominated with over 100 thousands pairs of plankton feeding little auks in Hornsund versus 2 thousand pairs in Kongsfjorden, and marine food consumption estimated as 5573 tonnes of carbon in Hornsund, versus 3047 tonnes in Kongsfjorden during one month of chick feeding period. Seabird colonies supply rich ornithogenic tundra (595 tonnes of C, as against only 266 tonnes of C in the Kongsfjorden tundra). No much of the terrestrial carbon, flushed out or wind-blown to the fjord, is consumed on the seabed – a state of affairs that is reflected by the low metabolic activity of bacteria and benthos and the lower benthic biomass in Hornsund than in Kongsfjorden.

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Benthic Crustacea and Mollusca distribution in Arctic fjord – case study of patterns in Hornsund, Svalbard

Drewnik A., Węsławski J. M., Włodarska-Kowalczuk M.

Oceanologia

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2017

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No. 59 (4)

565--575

EN

We present the results of species distribution modeling conducted on macrobenthic occurrence data collected between 2002 and 2014 in Arctic fjord – Hornsund. We focus on species from Mollusca and Crustacea taxa. This study investigates the importance of individual environmental factors for benthic species distribution, with a special emphasis on bottom water temperature. It aims to verify the hypothesis that the distribution of species is controlled by low water temperatures in the fjord and that the inner basins of the fjord serve as potential refugia for Arctic species threatened by the climate change-related intensification of warmer water inflows. Our results confirm the importance of bottom water temperature in regulating the presence of benthic fauna in the Hornsund fjord. The distribution of studied species is clearly related to specific water mass – colder (<1°C) or warmer (>1°C); and the preferred temperature regimes seem to be species specific and unrelated to analyzed groups. This study supports the notion that inner basins of the Hornsund fjord are potential refugia for cold water Arctic fauna, while the outer and central basins provide suitable habitats for fauna that prefer warmer waters.

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Large red cyanobacterial mats (Spirulina subsalsa Oersted ex Gomont) in the shallow sublittoral of the southern Baltic

Włodarska-Kowalczuk M., Balazy P., Kobos J., Wiktor J., Zajączkowski M., Moskal W.

Oceanologia

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2014

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No. 56 (3)

661--666

EN

We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other cyanobacteria, diatoms and nematode species were also present. After a few days in the laboratory, the red trichomes of S. subsalsa started to turn blue-green in colour, suggesting the strong chromatic acclimation abilities of this species.

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How lonely they are? A degree of isolation among macrozoobenthos species in the Marine Protected Area, the Bay of Puck, the Southern Baltic

Węsławski J. M., Kryla-Straszewska L., Warzocha J., Urbański J., Włodarska-Kowalczuk M., Kotwicki L.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

289--295

EN

Extensive sampling (450 grabs) was performed all over the inner part of Puck Bay (105 km2 area) in summers of 2007–2009. The GIS-based analysis of samples was performed to assess in detail the distribution of 32 benthic species. The minimum area of occurrence was less than 1 km2 for Lekanosphaera rugicauda and the maximum was 83 km2 for Cerastoderma glaucum. The material reveals that species with the pelagic larval stage were most widespread, with the least distance between individuals and the highest average density (e.g. Cerastoderma glaucum, Hydrobia ventrosa). The most isolated and the least dense species within the studied area were discretely mobile, non-larval crustaceans (e.g. Gammarus oceanicus and Lekanosphaera rugicauda), present at single sites with the largest distance from each other. We conclude that analysis of species distribution helps in understanding the threats to populations of marine invertebrates and marine spatial planning, through locating the isolated species and populations.

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Habitat modelling limitations - Puck Bay, Baltic Sea - a case study

Węsławski J.M., Kryla-Straszewska L., Piwowarczyk J., Piwowarczyk J., Urbański J., Warzocha J., Kotwicki L., Włodarska-Kowalczuk M., Wiktor J.

Oceanologia

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2013

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No. 55 (1)

167-183

EN

The Natura 2000 sites and the Coastal Landscape Park in a shallow marine bay in the southern Baltic have been studied in detail for the distribution of benthic macroorganisms, species assemblages and seabed habitats. The relatively small Inner Puck Bay (104.8 km2) is one of the most thoroughly investigated marine areas in the Baltic: research has been carried out there continuously for over 50 years. Six physical parameters regarded as critically important for the marine benthos (depth, minimal temperature, maximum salinity, light, wave intensity and sediment type) were summarized on a GIS map showing unified patches of seabed and the near-bottom water conditions. The occurrence of uniform seabed forms is weakly correlated with the distributions of individual species or multi-species assemblages. This is partly explained by the characteristics of the local macrofauna, which is dominated by highly tolerant, eurytopic species with opportunistic strategies. The history and timing of the assemblage formation also explains this weak correlation. The distribution of assemblages formed by long-living, structural species (Zostera marina and other higher plants) shows the history of recovery following earlier disturbances. In the study area, these communities are still in the stage of recovery and recolonization, and their present distribution does not as yet match the distribution of the physical environmental conditions favourable to them. Our results show up the limitations of distribution modelling in coastal waters, where the history of anthropogenic disturbances can distort the picture of the present-day environmental control of biota distributions.

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Macrozoobenthos of the sandy littoral zone in the military area between Hel and Jurata

Kotwicki L., Włodarska-Kowalczuk M., Wieczorek P.

Oceanological Studies

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1999

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Vol. 28, No. 3-4

97-107

EN

The aim of the study was to determine the distribution, composition and seasonal variability of macrozoobenthos in the sandy littoral zone of the military area between Hel and Jurata. The results of qualitative and quantitative investigations of the benthic fauna are presented. The material was collected monthly from November 1991 till November 1992 at 10 stations situated in the sandy littoral zone (0.5-1 m depth) on the Puck Bay shore of the Hel Peninsula. A total of 17 macrofaunal taxa were identified. At each station 2 or 3 subsamples were collected with a 225 cm2 Petersen grab. The average abundance and wet weight of particular taxa were calculated. Bathyporeia pilosa, Hediste diversicolor and Oligochaeta were most frequent taxa in the study area. Polychaeta and Bivalvia constituted up to 93% of the bottom fauna biomass, Hediste diversicolor was the dominant species.