Final answer:
The standing crop of phytoplankton can be measured using chlorophyll concentration or direct microscopic observation. Chlorophyll concentration involves filtering water samples and measuring the chlorophyll content, while direct microscopic observation counts and identifies phytoplankton cells.
Step-by-step explanation:
How are standing crop phytoplankton measured?
To measure the standing crop of phytoplankton, scientists often use a method called chlorophyll concentration. Chlorophyll is a pigment found in phytoplankton, and its concentration can be used as an indicator of the phytoplankton biomass. This measurement is done by collecting water samples, filtering them to separate the phytoplankton, and then measuring the chlorophyll content using a fluorometer. Another method is using direct microscopic observation, where a known volume of water is examined under a microscope, and the phytoplankton cells are counted and identified. These methods provide valuable data on the abundance and distribution of phytoplankton in various aquatic ecosystems.