A plankton net is equipment used for collecting samples of plankton in standing bodies of water. It consists of a towing line and bridles, nylon mesh net, and a cod end. Plankton nets are considered one of the oldest, simplest and least expensive methods of sampling plankton. The plankton net can be used for both vertical and horizontal sampling. It allows researchers to analyze plankton both quantitatively (cell density, cell colony or biomass) and qualitatively (e.g. Chlorophyll-a as a primary production of phytoplankton) in water samples from the environment.