3 sites in the Gdansk Basin: station 92A (54° 26'N, 18° 40'E), station R6 (54° 57.5'N, 18° 24'E), station G2 (54° 50'N, 19° 20'E). Station 92A was an inshore sheltered site; station R6 was located inshore; and station G2 was an offshore site close to the open sea

Plankton abundance per unit volume of the water column

The aim of this study was to obtain data on seasonal biomass variations and changes of taxonomic composition of nanoplankton in relation to some of the major factors influencing the succession. The exact sampling dates are as follows: 20-21 Jan, 11-14 Feb, 27 Feb-01 Mar, 23-25 Mar, 30 Mar-02 Apr, 13-15 Apr, 27-30 Apr, 11-13 May, 26-28 May, 15 Jun, 29 Jun-02 Jul, 14-17 Jul, 05-08 Aug, 23-27 Aug, 08-11 Sep, 22-25 Sep, 14-16 Oct, 26-29 Oct, 16-18 Nov, 03-05 Dec, 15-18 Dec 1987 and 12-15 Jan 1988. Water samples were drawn with a bathymeter from the following depth strata: 0-30m, every 5m; 30m-bottom, every 10m. Water samples were pooled according to the following depth layers: 0-15, 15-30, 30-60, 60-90 and 90m-bottom. Aliquots of 200ml were preserved with glutaraldehyde. One 10ml subsample was later allowed to sediment, and the organisms were identified under an inverted microscope. A total of 150 samples was analyzed. The organisms were identified to the highest possible taxonomic level; body volumes were estimated by approximating the actual body shape with a simplified geometric form. Enumeration was continued until 100 individuals were recorded, and at least 10 cell volumes were measured in each volume class.

National Marine Fisheries Research Institute
Kollataja 1
Gdynia

81-332
Poland