Oceanologia No. 37 (1) / 95

Papers

Sergey V. Semowski, Bogdan Wozniak
Institute of Oceanology, Polish Academy of Sciences, Sopot

Model of the annual phytoplankton cycle in the marine ecosystem-assimilation of monthly satellite chlorophyll data for the North Atlantic and Baltic
Oceanologia 1995, no. 37 (1), pp. 3–31

Keywords: Marine ecosystem; Phytoplankton; Dynamics modelling; Primary production; Remote sensing

Manuscript received November 23, 1994, in final form January 25, 1995.

Abstract

An annual-cycle model for the phytoplankton-zooplankton-nutrients ecosystem is presented for the North Atlantic and Baltic Sea. Satellite-derived surface chlorophyll data assimilation in the ecosystem model are discussed, and a number of methods of fitting model dynamics to the data are proposed. Statistical analysis of simulation results yields the main types of annual chlorophyll and primary production variability.

Jolanta Kusmierczyk-Michulec
Institute of Oceanology, Polish Academy of Sciences, Sopot

A semi-empirical expression for the solar spectral diffuse irradiance at the sea surface
Oceanologia 1995, no. 37 (1), pp. 33–45

Keywords: Diffuse irradiance; Southern Baltic Sea; Aerosol optical thickness Manuscript received November 7, 1994, in final form January 12, 1995.

Abstract

A simple, semi-empirical expression, valid in the visible spectrum for calculations of the solar diffuse irradiance, is presented. This relation is based on experimental data collected on cloudless days in 1993 and 1994 over the southern Baltic Sea. In order to illustrate the accuracy of the proposed formula, the aerosol optical thickness is calculated. The semi-empirical diffuse irradiance model can be used to make accurate calculations of the solar spectral diffuse irradiance and the aerosol optical thickness.

Jan Piechura, Waldemar Walczowski
Institute of Oceanology, Polish Academy of Sciences, Sopot

The Arctic Front: structure and dynamics
Oceanologia 1995, no. 37 (1), pp. 47–73

Keywords: Water masses; Front; Dynamics Manuscript received January 4, 1995, in final form February 2, 1995.

Abstract

During summer expeditions of r/v `Oceania´ to the Arctic Seas, the Arctic Front has been crossed and investigated each time since 1987. The 1993 cruise initiated more detailed investigations of this phenomenon. In the area delimited by longitudes 2^o41'W and 3^o05'E and latitudes 70^o54'N and 72^o32'N, five CTD transects were done with the CTD cast every 5 or 2 nm on each transect.

The location and direction of the front have been defined. The geostrophic component of the general circulation shows good agreement with the earlier data: a strong current (up to 40 cm s^-1) on the Atlantic side of the front, about zero velocity in the middle and a weak current (5–10 cm s^-1) on the Arctic side of the front. The steepest horizontal gradients were ca 0.5^oC km^-1 (temperature) and ca 0.04 psu km^-1 (salinity). The data reveal the complicated structure of the front with its intrusions, meanders and gyres.

Maciej Matciak, Jacek Nowacki
Institute of Oceanography, Gdansk University, Gdynia

The Vistula river discharge front – surface observations
Oceanologia 1995, no. 37 (1), pp. 75–88

Keywords: Plume front; Surface water properties; River Vistula Manuscript received December 8, 1994, in final form February 27, 1995.

Abstract

The spreading of Vistula river water has been studied on the basis of surface spatial distributions of water properties. The horizontal divergence field of the gradient of a given property is analysed to find the main directions of surface water transport. This shows that advection in the direction perpendicular to the frontal line is weak. Examples of salinity, temperature (AVHRR/SST), density and nutrient concentration fields in the area adjacent to the river mouth are discussed.

Grazyna Kowalewska
Institute of Oceanology, Polish Academy of Sciences, Sopot

Metalloporphyrins in recent sediments of the Baltic Sea
Oceanologia 1995, no. 37 (1), pp. 89–98

Keywords: Metalloporphyrins; Nickel(II); Vanadyl(II); Sediments; Sea; Baltic Manuscript received February 3, 1995, in final form March 21, 1995.

Abstract

Recent sediments of the southern Baltic Sea were investigated for the possible occurrence of metalloporphyrins. The content of both vanadyl(II) and nickel(II) metalloporphyrins estimated in the sediment samples studied is of the order of magnitude (1–6) x 10^-2 g g^-1 (d. w.). The results also suggest that the porphyrins in recent Baltic sediments are of anthropogenic origin. The highly significant correlation of the metalloporphyrin content with chlorophyll a indicates either that these metalloporphyrins are formed in the water column or that phytoplankton contribute to metalloporphyrin transfer from water to sediments.

Amany Mohamed Haroon
Academy of Scientific Research and Technology, National Institute of Oceanography and Fisheries, 101 Kaser El-eni St., Cairo, Egypt

Anna Szaniawska, Waldemar Surosz
Institute of Oceanography, Gdansk University, Gdynia

Changes in heavy metal accumulation in Enteromorpha spp. from the Gulf of Gdansk
Oceanologia 1995, no. 37 (1), pp. 99–110

Keywords: Enteromorpha spp.; Heavy metals; Gulf of Gdansk Manuscript received December 20, 1994, in final form March 9, 1995.

Abstract

The contents of Cu, Zn, Cd, and Pb were determined in samples of Enteromorpha spp. collected at Jurata at monthly intervals from November 1992 to October 1993, and at different stations on the coast of the Gulf of Gdansk during one month. Of all the metals analysed, Zn occurs in the highest concentrations, followed by Cu, Pb and Cd. In the samples from Jurata all the four metals displayed considerable seasonal variations in their concentrations, the ranges for each element being Zn – 29.80–90.05 g g^-1 dry wt., Cu – 12.82–28.41 g g^-1 dry wt., Pb – 1.81–7.08 g g^-1 dry wt. and Cd – 0.08–0.51 g g^-1 dry wt. The highest concentrations of all elements except Pb were recorded in November 1992.

Different concentrations of these metals were recorded in Enteromorpha spp. collected at different stations on the same day; the highest concentrations of Zn, Cu, and Pb were found in samples from Jastarnia (Zn – 72.11 g g^-1 dry wt., Cu – 48.19 g g^-1 dry wt. and Pb – 9.41 g g^-1 dry wt.), and from Gdynia (Zn – 65.29 g g^-1 dry wt., Cu – 29.13 g g^-1 dry wt. and Pb – 5.72 g g^-1 dry wt.). This implies a high level of pollution at these stations in comparison with the others. The highest concentration of Cd was recorded in samples from Puck (0.43 g g^-1 dry wt.).

Aldona Dobrzycka, Anna Szaniawska
Institute of Oceanography, Gdansk University, Gdynia

The effect of salinity on osmoregulation in Corophium volutator (Pallas) and Saduria entomon (Linnaeus) from the Gulf of Gdansk
Oceanologia 1995, no. 37 (1), pp. 111–122

Keywords: Osmoregulation; Salinity; Corophium volutator; Saduria entomon; Gulf of Gdansk Manuscript received January 30, 1995, in final form March 24, 1995.

Abstract

Material for the study was collected in the summer of 1994 in the Gulf of Gdansk where specimens of Corophium volutator and Saduria entomon – organisms living in a zone of critical salinity (5–8 psu) – commonly occur.

The high osmolarity of their body fluids is indicative of their adaptation effort to the salinity in their habitat. A species of marine origin, Corophium volutator maintains its osmotic concentration of haemolymph at a high level, as other species in brackish waters do; however, this is not the case with Corophium volutator specimens living in saline seas. Saduria entomon – a relict of glacial origin, originally from the Arctic Sea – also maintains a high osmotic concentration of haemolymph in comparison with specimens of this species living in the Beaufort Sea.

Marcin Plinski
Institute of Oceanography, Gdansk University, Gdynia

Phytoplankton of the Gulf of Gdansk in 1992 and 1993
Oceanologia 1995, no. 37 (1), pp. 123–135

Keywords: Phytoplankton; Seasonal changes; Distribution; Gulf of Gdansk Manuscript received December 13, 1994, in final form May 31, 1995.

Abstract

The article presents the results of a quantitative analysis of phytoplankton in the Gulf of Gdansk from samples taken in 1992 and 1993. The quantity of phytoplankton was higher in 1993 than in 1992. The greatest difference in cell numbers between the two years was found among the diatoms. A high number of dinoflagellates was observed during spring in both years.