National Monitoring Studies 2003, (Mesozooplankton)

Mesozooplankton samples were obtained using a vertical Juday plankton net with a 0.1 m² mouth opening and a mesh size of 150 μm. Vertical hauls were performed from 2 m above the seabed or from the lower boundary of the oxic layer to the surface, depending on local conditions.

The sampling depth was determined by accounting for both the length and the angle of the towing wire. Samples were fixed with 4% formaldehyde buffered to pH 8.0–8.2 using disodium tetraborate (borax; Na₂B₄O₇·10H₂O) and stored in plastic containers. Prior to analysis, the material was concentrated to 100–150 cm³ and divided into sub-samples.