engleski

Vertical distribution of protozoan and microcopepod communities in the South Adriatic Pit

The qualitative composition, numerical abundance and vertical distribution of radiolarians, tintinnines, nauplii and small copepod assemblages was studied in the central area of the Southern Adriatic Pit at three stations during ten cruises from October 1985 to May 1990. The samples were collected with a plankton net of 53 ľm mesh size equipped with a closing system in eight vertical layers. In the paper data are presented for 53 radiolarians, 61 tintinnines and first time for 22 poecilostomatoid species in the Adriatic Sea. According to the numerical abundance of assemblages and frequency of the occurrence of the bulk of the individual species population in the water column four communities could be defined ; the surface (0-50 m), the subsurface (50-100 m), the midwater (100-600 m) and the deep-sea community (below 600 m). The euphotic layer was characterized by tintinnines, copepod nauplii, cyclopoids and juvenile calanoid copopods, while radiolarians and poecilostomatoid copepods dominated in the deeper layers. The highest numerical differences between stations and seasons were noted only on the surface. Towards the deepen layers the differences were constantly smaller, and under 400 m these was a uniform distribution of all assemblages. This research, on the basis of the numerical abundance of protozoans and micrometazoans, shows that the central part of the South Adriatic Pit is considerably richer then mentioned by earlier authors.

protozoa; microcopepod communities; Adriatic sea

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