Mesozooplankton and phytoplankton time series of the Baltic Monitoring Program (BMP)

Within the monitoring programme of the Helsinki Commission (HELCOM) the mesozooplankton of the Bornholm Basin (ICES subdivision 25, station BMP-K2) was sampled by the WP-2 net (lOOfJm) 5-8 times a year in 1988-1992. Abundance, biomass, secondary production and productivity (P/B) were given for mesozooplankton groups and copepod species. Environmental factors recorded were temperature, chlorophyll a and primary production. Within copepods, the dominant species were Temora longicornis and Pseudocalanus minutus with yearly peak values of 40-50% of the monthly copepod numbers and biomasses. The annual production of Temora longicornis was highest (6.5g C/m**2/y). The biomass of all copepods was at its maximum in June (mean = 2.25g C/m**2), especially in 1992 (3.65g C/m**2). The differences between results from two methods used to calculate the production of copepods were greatest in June and July. The cladocerans were only important in summer and the appendicularians only in spring. The productivity (P/B) of the appendicularians was highest of all mesozooplankton groups. Numbers and the biomass of the meroplankton were one or two orders of magnitude below the holoplanktic groups.

Occurrence of species-indicators and zooplankton biomass in the Barents Sea in September-October 1997

Samples of zooplankton were collected in the Barents Sea during cruise 11 of R/V Akademik Sergey Vavilov in September-October 1997. Three different sampling methods were used: 30 l bottle, Judey net, and BR net. More than 40 species of zooplankton were revealed. The greatest species diversity occurred in zones of junction of waters of different origin. Within the 100 m upper water layer zooplankton biomass was rather high: aver. 32 g/m**2. The highest biomass was observed in the northeastern part of the region under study and over the shelf of the Russkaya Gavan' Bay. The lowest biomass occurred in the southern part and in the region of the Gusinaya Banka. The average autumn value of zooplankton biomass in the 100 m upper layer (321 mg/m**3) slightly exceeded the multiannual average for the summer period (200 mg/m**3)