In Figure 8, we show the monthly averages of the ratio (w:w) of available
N:available P (defined here as DIN:TDP) from January 1994 through December
1995 compared with the multi-year monthly averages of this ratio. From May
until September 1994, this ratio was slightly lower than the multi-year average.
Thereafter, until the end of 1995, it remained higher than average.
Alkaline phosphatase activity
During the cyanobacterial bloom in late September and October 1994, alkaline
phosphatase activity in the epilimnion was extremely high (2800 nmol MU I"1
h"1
),
-4-fold greater than during the Peridinium bloom, despite the much lower algal
standing stock. SRP concentrations were near or below our detection limits (-1
ug P I"1
) at this time (O.Hadas and R.Pinkas, unpublished data).