Plakton blooms can be quite variable which affects the way pelagic and benthic resources utilize the primary production associated with the bloom. In an attempt to quantify these characteristics, two measures of bloom size are reported, chlorophyll intensity and chlorophyll magnitude, which are a reflection of the concentration and duration of the bloom, respectively:

Intensity: is the mean chlorophyll concentration for the seasonal time period in a region.

Magnitude: is the mean chlorophyll concentration for a seasonal time period multiplied by the length of the time period. In some years, the time period start or stop dates were not obvious from the annual data, in these cases the climatological time period was used instead.

This figure illustrates the differences between high and low intensity versus high and low magnitude blooms.