| Abstract [eng] |
Background. Copepods are major secondary producers in the World Ocean. They represent an important link between phytoplankton, microzooplankton and higher trophic levels such as fish. They are an important source of food for many fish species but also a significant producer of detritus. In the terms of the role they play in the marine food web, it is important to know how environmental variability affects the population of copepods. Methods. The study of the zooplankton community in the south-eastern Baltic Sea conducted during a 24-month survey (from January 2010 to November 2011) resulted in the identification of 24 invertebrate species (10 copepods, seven cladocerans, four rotifers, one ctenophore, one larvacean, and one amphipod). Data were collected at two stations located in the open sea waters of the Gulf of Gdansk: the Gdansk Deep (P1) (54 degrees 50'N, 19 degrees 19'E) and in the western, inner part of the Gulf of Gdansk (P2) (54 degrees 32'N, 18 degrees 48.2'E). The vertical hauls were carried out with the use of two kinds of plankton nets with a mesh size of 100 mu m: a Copenhagen net (in 2010), and a WP-2 net (in 2011). Results. The paper describes the seasonal changes in the abundance and biomass of copepods, taking into account the main Baltic calanoid copepod taxa (Acartia spp., Temora longicornis and Pseudocalanus sp.). They have usually represented the main component of zooplankton. The average number of copepods at the P1 Station during the study period of 2010 was 3,913 ind m(-)(3) (SD 2,572) and their number ranged from 1,184 ind m(-3) (in winter) to 6,293 ind m(-3 )(in spring). One year later, the average count of copepods was higher, at 11,723 ind m(-3 )(SD 6,980), and it ranged from 2,351 ind m(-3 )(in winter) to 18,307 ind m(-3) (in summer). [...]. |
