Lucyna Falkowska
Institute of Oceanography, Gdansk University, Gdynia
Keywords: Seepage, Convection, Gdansk Deep, Nutrients Manuscript received February 26, 1998, in final form March 17, 1998.
Seepage of freshwater into the near-bottom layer (ca 100m depth) of the Gdansk Deep was reported during short-term studies on the variations of concentration of chemical compounds and the stratification of this basin. As a result, the salinity fell to below 1 PSU and the temperature rose from 5 to ca 7.5oC in this layer; further consequences were changes in the chemical and hydrological stratification throughout the water column. Directly above the area of seepage there was a zone of powerful turbulent convection where the temperature-salinity Rayleigh number was of the order of 1016. Large quantities of suspended matter and poorly oxygenated deep waters were carried by the convection current from below the halocline up to the sea surface. This seepage of groundwaters is probably a continual and not an intermittent phenomenon.
Short-term changes in the hydrochemical constituents in the water column of the Gdansk Deep (Baltic Sea) in spring. Part 1. Nutrient and
oxygen concentrations in relation to the density stratification:
Oceanologia 1998, no. 40 (2), pp. 83–104
Lucyna Falkowska, Dorota Burska, Jerzy Bolalek
Institute of Oceanography, Gdansk University, Gdynia
Dorota Roguszczak
Pedagogical University, Slupsk
Keywords: Nutrients, Oxygen, Density, N:P ratio, Gdansk Deep Manuscript received February 26, 1998, in final form May 4, 1998.
Both the seasonal thermocline in the uppermost layer of the sea and the halocline in the near-bottom layer were found to constrain transport of chemical compounds to the productive layer of the Gdansk Deep. The occasional disappearance of the halocline resulted on the one hand in the flow of nitrogen and phosphorus compounds through the intermediate layer towards the surface, and on the other in a considerable improvement in oxygen conditions in the near-bottom layer, this usually being either poorly oxygenated or anoxic. A statistically significant negative correlation between nitrate and oxygen concentrations was found in the isohaline layer. The N:P ratio was usually low during the day but increased at night. During spring this ratio increased in the euphotic layer. The large number of high N:P ratios may attest to the shortage of phosphates and to the change in the limiting factor – from nitrogen compounds in early spring to phosphates in late spring.
Lucyna Falkowska
Institute of Oceanography, Gdansk University, Gdynia
Keywords: Nutrients, Diel cycle, Non-linear regression, Gdansk Deep Manuscript received February 26, 1998, in final form May 4, 1998.
The paper deals with the diel fluctuations of nutrient concentrations and oxygen in the euphotic layer of the Gdansk Deep in spring in the years 1989–1996. Using non-linear regression, these diel variations were modelled under a variety of typically spring density stratifications: in the absence of thermal layering, in the presence of a distinct thermocline and during thermocline formation. The diel cycle of nutrients in the euphotic layer showed two maxima and two minima, probably due to variability in photosynthetic intensity.
Hanna Mazur
Department of Plant Physiology, Gdansk University, Gdynia
Keywords: Auxin, Indole-3-acetic acid (IAA), Marine sediments, Southern Baltic Manuscript received March 27, 1998, in final form May 13, 1998.
Analyses of indole-3-acetic acid (IAA) in sediments collected at stations in the southern Baltic Sea were carried out by HPLC. The seasonal variations in IAA content as well as the relationship between organic matter content and the concentration of IAA were shown. A decrease in IAA concentration with depth was observed in the sediment profiles from the Gdansk Deep, the Bornholm Deep and Slupsk Furrow.
Zbigniew Mudryk, Piotr Skorczewski
Department of Experimental Biology, Pedagogical University, Slupsk
Keywords: Marine bacteria, Antibiotic resistance, Southern Baltic Sea Manuscript received March 17, 1998, in final form May 11, 1998.
This study deals with the antibiotic resistance of heterotrophic bacteria isolated from the surface and subsurface water of the Gdansk Deep. The level of resistance of bacteria to various antibiotics differed considerably. As a rule, there were no significant differences in antibiotic resistance between neustonic and planktonic bacteria. Considerable diel fluctuations in bacterial antibiotic resistance were found. There were significant differences between pigmented and non-pigmented bacteria in their resistance to the tested antibiotics. Bacterial resistance to antibiotics was dependent on their chemical structure.
Krystyna Olanczuk-Neyman, Katarzyna Jankowska
Faculty of Environmental Engineering, Technical University, Gdansk
Keywords: Saprophytic bacteria, Indicator bacteria, Sandy beach, Baltic Sea Manuscript received March 27, 1998, in final form May 18, 1998.
The paper presents the results of bacteriological investigations relating to the coastal seawater and sandy sediments along the beach in Sopot in an area between the mouths of two streams, Grodowy Potok and Kamienny Potok. The sandy sediments investigated at four sites along a transect perpendicular to the shore contained variable numbers of saprophytic bacteria. In areas close to the littoral zone large numbers of allochthonous bacteria were found. With increasing distance from the waterline their domination declines to the advantage of autochthonous bacteria, an indication of the decreasing influence of anthropogenic pollution.
Malgorzata Radlowska, Janusz Pempkowiak
Institute of Oceanology, Polish Academy of Sciences, Sopot
Keywords: Stress proteins, Mytilus trossulus, Toxicant exposure, Western blotting
The exposure of organisms to environmental stressors affects the expression levels of certain 'stress proteins' that play an important role in protein homeostasis and stress tolerance. Examining the protein profiles by SDS–PAGE and Western blotting analysis, mussels Mytilus trossulus were exposed to cadmium, which induced a number of Hsp70 proteins in accordance with the metal concentrations. In immunodetection two commercial monoclonal antibodies were used to monitor this response in gill tissue. It follows that Hsp70, which is typically induced by moderate heat-shock treatment, is in most cases also induced in the presence of cadmium.
Dorota Napierska
Biological Station, Gdansk University, Sobieszewo
Malgorzata Radlowska
Institute of Oceanology, Polish Academy of Sciences, Sopot
Keywords: Stress proteins, Metallothionein, Cadmium, Immunodetection, Shrimp Crangon crangon
Shrimps were exposed to various concentrations of CdCl2 under laboratory conditions for 96 h. Abdominal muscles were isolated from exposed and control animals. The induction of stress proteins (heat shock proteins of the Hsp70 family and metallothionein) was detected following polyacrylamide gel electrophoresis in the presence of SDS (SDS–PAGE) and specific staining (Western blotting method in the case of the Hsp70 or Coomassie blue and silver staining in the case of metallothionein). The short-term cadmium poisoning in the shrimp Crangon crangon resulted in the induction, in a concentration-dependent manner, of metallothionein and a new protein with an approximate molecular weight of 70 kDa in abdominal muscle. This protein was immunologically cross-reactive with the 70 kDa heat shock protein of the mouse.