A quantitative survey of the benthic meiofauna in the Gulf Of Riga (eastern Baltic Sea), with special reference to the structure of nematode assemblages

Abstract

Abstract The Gulf of Riga is relatively shallow and considered to be one of the most eutrophied areas in the Baltic Sea with an annual primary production estimated to 290 gCm-2 yr-1. Meiofauna sampling was carried out at 30 stations homogeneously spread over the Gulf of Riga, varying in depth and sediment structure. The average meiofauna abundance was 4800 ind/10 cm2, with a maximum of 17000 ind/10 cm2. Harpacticoid copepods were abundant all over the Gulf, averaging 425 ind/10 cm2. The highest number was found close to the mouth of the river Daugava, up to 1400 ind/10 cm2. Harpacticoids were significantly more abundant in sediments with medium organic content (loss on ignition (LOI) 5–10%) compared to sediments with low organic content (LOI 10%). Other major taxa were not correlated with sediment organic content. Altogether, 38 nematode spec...