Wyniki wyszukiwania - BazTech

1

New records of Conrad’s false mussel Mytilopsis leucophaeata (Conrad, 1831) in the Vistula Delta

Brzana R., Janas U., Borecka A.

Oceanological and Hydrobiological Studies

|

2017

|

Vol. 46, No. 2

231--236

EN

Mytilopsis leucophaeata (Conrad, 1831) is native to the western Atlantic coast of North America. It has been reported in many regions outside its home range, including the Gulf of Gdańsk (the southern Baltic Sea). Although the conditions in the area seem to be favorable for the species, there have been no reports about its presence elsewhere in the gulf. However, the data probably did not reflect its actual distribution in the region, as the species can be easily misidentified for other bivalves living in the area, and it prefers hard substrates, which have not been studied as extensively as soft substrates. Our study was aimed at determining the actual distribution of M. leucophaeata in the Gulf of Gdańsk, the Vistula Delta and the Vistula Lagoon. The results showed that the species was not widely distributed in the Gulf of Gdańsk and was absent in the Vistula Lagoon. The only new records come from the Vistula Delta where the abundance of M. leucophaeata was up to 69 ind. m-2, i.e. significantly higher than in the Gulf of Gdańsk. Individuals found in the Vistula Delta were also significantly larger, with the length of shells reaching 22-23 mm, which is considered to be the maximum for the species.

2

Assessment of biodiversity and environmental quality using macrozoobenthos communities in the seagrass meadow (Gulf of Gdańsk, southern Baltic)

Dąbrowska A. H., Janas U., Kendzierska H.

Oceanological and Hydrobiological Studies

|

2016

|

Vol. 45, No. 2

286--294

EN

This study shows the macrozoobenthic biodiversity and the quality status of the Zostera marina meadow in the Gulf of Gdańsk. To our knowledge, this is the first study focused on the assessment of environmental quality based on macrofauna occurring on such a small and specific habitat as a seagrass meadow. The meadow is dominated by Zostera marina, but also Zanichellia palustris and Potamogeton pectinatus are present. Compared to the soft bottom macrofauna in the southern Baltic, the biodiversity of macrozoobenthos is very high, which is reflected in 33 taxa observed during the whole research, while the mean number of taxa was 12. There were also some taxa found only on the bottom overgrown with vegetation, e.g. Idotea balthica or even taxa that are currently rarely observed in the Gulf of Gdańsk, e.g. Gammarus locusta or Gammarus ineaquicauda. Nineteen percent of the stations were classified into the very good quality status and 50% into the good quality status, so the environmental status of this meadow based on the BQI index is assessed as good. Given these results, this is probably one of the best preserved meadows in the southern Baltic.

3

Artificial hard substrate as a habitat for hard bottom benthic assemblages in the southern part of the Baltic Sea : a preliminary study

Brzana R., Janas U.

Oceanological and Hydrobiological Studies

|

2016

|

Vol. 45, No. 1

121--130

EN

Benthic species associated with hard substrate are known to form communities characterized by high abundance and biomass. Although the bottom of the Southern Baltic Sea is dominated by soft sediments, such communities find favorable conditions to thrive on artificial substrates of offshore constructions. The aim of this research was to characterize both short-term and long-term benthic communities associated with artificial hard bottom provided by man-made structures in the Southern Baltic Sea. Species composition as well as the abundance and biomass were examined at various sites. An inactive World War II torpedo testing facility in the Gulf of Gdansk served as a site for sampling long-term communities while short-term communities were sampled using settlement panels and PVC cylinders. Panels were deployed at the torpedo testing facility for 127 days. PVC cylinders were deployed for 141-190 days in the Polish Exclusive Economic Zone. Twenty six macrofaunal taxa, including 12 crustaceans, were identified during the research. Mytilus edulis and Amphibalanus improvisus were the most abundant invertebrates at sampled surfaces. Six non-indigenous species were found. For the first time adult individuals of Mytilopsis leucophaeata were found in the Polish Marine Areas indicating that it is possible for this nonindigenous species to reproduce in this region.

4

The first record of Piscicola pojmanskae Bielecki, 1994 in the Gulf of Gdańsk (the southern Baltic Sea) with species characteristics distinguishing it from Piscicola geometra (Linnaeus, 1758)

Kendzierska H., Dąbrowska A. H., Cichocka J. M., Janas U., Bielecki A.

Oceanological and Hydrobiological Studies

|

2014

|

Vol. 43, No. 3

324--327

EN

Specimens of Piscicola pojmanskae were identified in the macrozoobenthos community in Zostera meadows in Puck Bay. The presented paper is the first report on the observation of this species in the Gulf of Gdańsk (the southern Baltic Sea). Leeches are a rare component of the benthic fauna in this brackish water area.

5

Non-indigenous bivalve - the Atlantic rangia Rangia cuneata - in the Wisła Śmiała River (coastal waters of the Gulf of Gdańsk, the southern Baltic Sea)

Janas U., Kendzierska H., Dąbrowska A. H., Dziubińska A.

Oceanological and Hydrobiological Studies

|

2014

|

Vol. 43, No. 4

427--430

EN

The present paper reports on the occurrence of the Atlantic rangia Rangia cuneata in the Wisła Śmiała River (coastal waters of the Gulf of Gdańsk, the southern Baltic Sea) from around 2012–2014.

6

First record of the oriental shrimp Palaemon macrodactylus M. J. Rathbun, 1902 in the Baltic Sea

Janas U., Tutak B.

Oceanological and Hydrobiological Studies

|

2014

|

Vol. 43, No. 4

431--435

EN

The present paper reports for the first time on the occurrence of the oriental shrimp Palaemon macrodactylus M. J. Rathbun, 1902 in the coastal waters of the Baltic Sea in 2014. Ovigerous females and young individuals were found, indicating a possible establishment of this species in the Baltic Sea.

7

Benthic non-indigenous species among indigenous species and their habitat preferences in Puck Bay (southern Baltic Sea)

Janas U., Kendzierska H.

Oceanologia

|

2014

|

No. 56 (3)

603--628

EN

To date 11 non-indigenous benthic taxa have been reported in Puck Bay (southern Baltic Sea). Five of the 34 taxa forming the soft bottom communities are regarded as non-indigenous to this area. They are Marenzelleria spp., Mya arenaria, Potamopyrgus antipodarum, Gammarus tigrinus and Amphibalanus improvisus. Non-indigenous species comprised up to 33% of the total number of identified macrofaunal taxa (mean 17%). The average proportion of aliens was 6% (max 46%) in the total abundance of macrofauna, and 10% (max 65%) in the biomass. A significant positive relationship was found between the numbers of native taxa and non-indigenous species. The number of native taxa was significantly higher on a sea bed covered with vascular plants than on an unvegetated one, but no such relationship was found for their abundance. No significant differences were found in the number and abundance of non-indigenous species between sea beds devoid of vegetation and those covered with vascular plants, Chara spp. or mats of filamentous algae. G. tigrinus preferred a sea bed with vegetation, whereas Marenzelleria spp. decidedly preferred one without vegetation.

8

Body size and reproductive traits of Palaemon elegans Rathke, 1837 (Crustacea, Decapoda), a recent colonizer of the Baltic Sea

Janas U., Mańkucka A.

Oceanological and Hydrobiological Studies

|

2010

|

Vol. 39, No.2

3-24

EN

Palaemon elegans is a species of prawn new (since 2000) to the southern Baltic. The aim of this study was to find out whether there are differences in the sizes of individuals and in the reproductive traits of P. elegans inhabiting different areas of the southern Baltic Sea and to compare the data obtained with existing data for populations from other coastal areas. The present study was carried out in the summers of 2005 and 2007 in three areas differing in their hydrological conditions (primarily in salinity): Puck Bay (PB), the Vistula Delta (VD) and the Vistula Lagoon (VL), Poland. The maximum body lengths of these prawns (females = 60 mm, males = 41 mm), and body masses (1201 mg and 533 mg respectively) found in the southern Baltic were less than those reported from many other parts of the geographical range of this species. The increase in body mass with length was the smallest in the prawns inhabiting VL, and the maximum lengths they grew to were also shorter (females – 52 mm and males – 39 mm) than in PB. The numbers of eggs carried by P. elegans in the southern Baltic were smaller than those found in females in its native regions. Differences were also found in the numbers and sizes of eggs between prawns inhabiting different locations in the southern Baltic. It was concluded that the low salinity of the southern Baltic Sea (even below 7 PSU), while not preventing this prawn from reproducing, caused a shift to the production of fewer but larger eggs. The reproductive strategy that Baltic populations of P. elegans has adopted is one of the factors responsible for its very rapid and large-scale colonization of the southern Baltic Sea.

9

Energy values and energy resources of two prawns in Baltic coastal waters: the indigenous Palaemon adspersus and the non-indigenous Palaemon elegans

Janas U., Bruska O.

Oceanologia

|

2010

|

No. 52 (2)

281-297

EN

Until recently only two palaemonid species inhabited the southern Baltic: Palaemon adspersus and Palaemonetes varians. Soon after the year 2000 a new species - Palaemon elegans - arrived and quickly established itself as a new component in the trophic web. The objects of this research were to define the energy value and energy resources of P. elegans and to compare them with the corresponding values for the native P. adspersus. These parameters will supply information about this new link in the trophic web and may help to explain the part played by the new prawn and its population in the energy flow. This work demonstrated that the energy values of both prawn species were very much the same: the average energy value of P. elegans was 16.5š2.1 J mg-1 DW (19.3š2.5 J mg-1AFDW) (N = 150), that of P. adspersus was 16.7š2.1 J mg-1 DW (19.5š 2.5 J mg-1 AFDW) (N = 71). No statistically significant differences in energy value were found between the two species with respect to sex, size or season. The results show that P. elegans is an energetically valuable food item for predators. Its energy resources in Polish brackish coastal waters can be as high as 150 kJ m-2; the highest among the palaemonid species in this habitat, they constitute a rich supply of food for other organisms.

10

Object-oriented classification of QuickBird data for mapping seagrass spatial structure

Urbański J.A., Mazur A., Janas U.

Oceanological and Hydrobiological Studies

|

2009

|

Vol. 38, No.1

27-43

EN

QuickBird satellite images were processed using object-based analysis to map the spatial structure of seagrass in sandy shoal habitat in the southern Baltic Sea. A three-level ecological model of seagrass landscape, composed of meadows, beds and patches/gaps, was implemented in the multi-scale object domain. Image segmentation was performed at different spatial scales. In order to determine representative scales for bed level and patch/gap level objects, histograms of delineated objects were analyzed. Using object-oriented classification methods, two hierarchically nested maps of seagrass spatial structure were created. The map of patches/gaps was created using the nearest neighbor classification method in the feature space defined by the mean value of band 2 and the value of the proposed seagrass index. Overall map accuracy was 83%. The second map, which depicted the cover density of seagrass beds, was created on the basis of hierarchical relationships between objects at two chosen spatial scale levels. Both maps were exported as vector objects to GIS. Vector-based mapping of seagrass landscape structures at two scales simultaneously provides new possibilities for using landscape metrics and time change detection methods.

11

What is the diet of Palaemon elegans Rathke, 1837 (Crustacea, Decapoda), a non-indigenous species in the Gulf of Gdańsk (southern Baltic Sea)?

Janas U., Barańska A.

Oceanologia

|

2008

|

No. 50 (2)

221-237

EN

Palaemon elegans, a new component of the Gulf of Gdańsk macrozoobenthos, colonised the southern Baltic coastal zone in the late 20th and early 21st century. Analysis of the stomach contents of P. elegans revealed 16 plant and animal taxa that these prawns had fed on. The principal dietary component was detritus, with a mean frequency of occurrence in stomachs of > 80%. The most frequently occurring plant components in the diet were algae from the genus Cladophora and the family Ectocarpaceae, while the most significant animal components were Harpacticoida, Chironomidae, Ostracoda and Gammarus spp. The results of the study show that the dietary composition of P. elegans differed significantly between stations and months. The foraging area consisted of two distinctive regions - the Inner Puck Bay, and the Outer Puck Bay together with the Dead Vistula River; two of the stations - Gdynia and Sopot - were distinct from all the others. However, no obvious seasonality in the food composition could be demonstrated.

12

Submerged objects - a nice place to live and develop. Succession of fouling communities in the Gulf of Gdańsk Southern Baltic

Dziubińska A., Janas U.

Oceanological and Hydrobiological Studies

|

2007

|

Vol. 36, No.4

65-78

EN

The process of ecological succession in marine fouling communities was investigated at two study sites in the Gulf of Gdańsk, Gdynia and Gdańsk. Settlement panels were used as substrata for sessile organisms, and the study lasted 150 days between May and October 2005. Communities were dominated by two species, Balanus improvisus and Mytilus trossulus. The process of succession differed at these two study sites, particularly in the final part of the experiment. Four stages of succession were distinguished at both study sites; at Gdańsk: (1) Biofilm - phase, (2) Green algae - phase, (3) Balanus - phase, (4) Ectocarpaceae - phase; at Gdynia: (1) Biofilm - phase, (2) Balanus - phase, (3) Green algae - phase, (4) Mytilus - phase.

13

The beachflea Platorchestia platensis (Kroyer, 1845): a new addition to the Polish fauna (with a key to Baltic talitrid amphipods)

Spicer J.I., Janas U.

Oceanologia

|

2006

|

No. 48 (2)

287-295

EN

The present paper reports for the first time on the occurrence of Platorchestia platensis (Kroyer, 1845) (Crustacea, Amphipoda) in Puck Bay (southern Baltic, Poland) in May 2005. A key to the Baltic talitrids is given, which can be used to identify males and females of the four species occurring on Polish shores (Talitrus saltator, Talorchestia deshayesii, Orchestia cavimana, Platorchestia platensis) and additionally Orchestia gammarellus, which may yet be found in the Polish coastal zone.

14

Seasonal and annual changes in the macrozoobenthic populations of the Gulf of Gdańsk with respect to hypoxia and hydrogen sulphide

Janas U., Wocial J., Szaniawska A.

Oceanologia

|

2004

|

No. 46 (1)

85-102

EN

This study was designed to investigate seasonal and annual changes in the benthic macrofauna in relation to changes in hydrogen sulphide concentration in the sediment and the oxygen content in the water column. Data were collected over a three-year period from 1994 to 1997. The benthic macrofauna inhabiting the sediments of the Gulf of Gdansk, in which H2S is permanently present, consists mostly of species with a high tolerance to oxygen deficiency and the presence of H2S. These species are: Macoma balthica, Harmothoe sarsi, Nereis diversicolor, Saduria entomon and Halicryptus spinulosus, as well as Pontoporeia femorata and Corophium volutator, which are more sensitive to these factors. In 1996-1997 a decline in the abundance of almost all benthic species, and especially of the bivalve M. balthica at all the stations was observed in comparison to 1994-1995.

15

Palaemon elegans - a new component of the Gulf of Gdańsk macrofauna [commun.]

Janas U., Zarzycki T., Kozik P.

Oceanologia

|

2004

|

No. 46 (1)

143-146

EN

The present paper reports on the occurrence of the prawn Palaemon elegans Rathke in the coastal waters of the Gulf of Gdańsk in the years 2002-2003, and in other regions of the Baltic Sea as recorded by various authors.

16

The biochemical composition of Enteromorpha spp. from the Gulf of Gdansk coast on the southern Baltic Sea

Haroon A. M., Szaniawska A., Normant M., Janas U.

Oceanologia

|

2000

|

No. 42 (1)

19-28

EN

Variations in lipid, protein and carbohydrate contents of Enteromorpha spp. were examined over a seven-month period from April to October 1993. The samples were collected from seven sampling stations along the Gulf of Gda/nsk coast. The lipid content was low and varied slightly from 3.47 š 1.76% of DW at Puck to 4.36 š 2.17% of DW at Rewa and Cha/lupy. The protein content varied from 9.42 š 4.62% of DW at Puck to 20.60 š 5.00% of DW at Jurata. At the remaining stations the values vary over a narrow range. The maximum protein contents were recorded at the beginning and end of the growing season. The level of carbohydrate was very high compared to that of lipid and protein and varied from 29.09 š 6.44% of DW at Oslonino to 39.81 š 11.15% of DW at Puck. Seasonal carbohydrate changes were noted at all sampling stations, the minimum occurring in spring and autumn and the maximum in summer.