The proportion of the total wet weight biomass that was identified
to at least species (Fig. 4A) or genus levels (Fig. 4B) varied
substantially, suggesting differences in the taxonomic resolution
and traditions between the involved institutions. On average, the
proportion of biomass indentified to species level varied from 0.9) in San Francisco Bay
and Norderney data sets. The average proportion of at least genus
level biomass was generally >0.9, while Dutch coastal and Patos
Lagoon Estuary data sets had consistently lower proportions. In the
Norderney, and particularly the San Francisco Bay data sets an
exceptionally low proportion of phytoplankton was identified to
higher than genus level.