I have done a number of posts on the quality of Long Island Sound and some of the things i have found in my testing.
Others who did much more in depth research have found that the size of the plankton determines which species are favored (Capriulo, G.M. (December 1996), Connecticut DEP Long Island Sound Research Fund-Alteration of the Planktonic Food Web of Long Island Sound Due to Eutrophication.).
The research showed that the normal flora of the Sound was being replaced with nano and pico sized flora.
Now back to my Statements, first let us consider made made fertilizers, which use the salts of Ammonium, Nitrate and Phosphate. When they are washed out, they wash out as salts, ionic molecules which are small and that would produce the nano and pico sized plankton.
Decomposing leaves, manure, sewage and composting organic materials are going to be found in larger clumps and will produce larger size plankton.
This is why I do not use man made fertilizer, but do use a compost of leaves and other organic items myself.
I have great vegetables - you can ask my neighbors.