Marine Biology (2+1)

METHODS OF COLLECTION

The nanophytoplankton compared to net phytoplankton has smaller number of species. However, its chief constitutents, viz. flagellates and diatoms which have a size range of 5-20 µm contribute more than 90% in the phytoplankton biomass. A few milliliters of water sample may invariably be sufficient for a representative nanophytoplankton sampling. However, for the collection of microplankton (net plankton) having more than 20 µm which is poor in counts but rich in species, large volumes of water samples have to be filtered. Generally, for the estimation of surface standing crop of phytoplankton, water samples are collected from the surface with the help of a scoop bucket. On the other hand, for the estimation of the standing crop of subsurface and deeper layers, depending on the nature of study, suitable methods have to be followed for collecting the plankton samples. The different methods of collection of phytoplankton in vogue are described below.