A new divided neuston sampler in two modifications: Description, tests, and biological results

Publisher Website
Google Scholar
Abstract
The larger sampler consists of a rectangular aluminium frame and two sausageshaped floats mounted on brackets. The nets are sewn to frames (50 × 20 cm) with hollow tubes welded to the ends, through which two sliding aluminium bars fit and secure the nets to the main frame. Five nets are placed at predetermined depths to a maximum of 90 cm. They can be changed — different mesh sizes: 150-500 μm — and collecting depth can be regulated within 5 minutes at sea. A flow meter measures the length of the water column which passes through the nets. The sampler is towed from a bridle in undisturbed water alongside and astern of the ship. Normally, a 5 minutes haul with a speed of 1.5 knots gives a filtered volume of 25 m3 per net. The gear has been used in Oslofjorden, Skagerrak, North Sea, and off Spitsbergen, is easy to handle, more versatile than those previously described, and floats vertically following the movements of the waves even in high seas. The ‘mini-neuston’ sampler is a simpler device, designed for use from a smaller boat close to land. It is similar to the larger sampler but lacks the main frame and takes fewer but the same nets. The precision of the gear is documented with statistical analysis on 9 series each of 4-8 neuston hauls.