This process takes place almost continuously as a "marine snow" of descending particles, falling at the rate of about 100 to 150 m (328 to 492 ft) per day.
[1] Under certain conditions, phytoplankton may aggregate and fall rapidly through the water column to arrive little changed on the seabed.
These fluxes sometimes occur seasonally or periodically, are sometimes associated with algal blooms and may constitute the greater part of descending organic matter.
If the amount is greater than the benthic detritivores can process, the phytodetritus forms a fluffy layer on the surface of the sediment.
It includes the microscopic remains of diatoms, dinoflagellates, dictyochales, coccolithophores, foraminiferans, phaeodareans, tintinnids, crustacean eggs and moults, protozoan faecal pellets, picoplankton and other planktonic matter embedded in a membranous gelatinous matrix.