Your information is incorrect. Many microalgae have no trouble
assimilating and utilizing ammonium or urea as nitrogen sources. My
experience has shown that ammonium tends to be depleted somewhat more
rapidly than some other nitrogen sources, probably because there are
fewer steps required to permit its use by the cell. Nitrate, nitrite
and urea must all be reduced by energy-consuming reactions to ammonia
once they've been assimilated.
Not the same thing a bit!' said the Hatter. `You might just as well say
that I see what I eat is the same thing as I eat what I see!
Robert J. Lebowitz Department of Biological Sciences
lebowitz at krypton.mankato.msus.edu Mankato State University, Minnesota