Abstract
Seasonal characteristics of the spatial distributions of NO3-N, NH4-N and PO4-P in Tokyo Bay were revealed by applying statistical methods to the monitoring data obtained at 41 observation points every month from April 1985 to March 1990.
In the surface layer, the concentrations of the three nutrients were always high near the mouths of the big rivers which are located at the head and the west coast of the bay, and those were low at the mouth of the bay. The difference between the concentrations of NO3-N at the mouths of the rivers and those at the offing was relatively larger during spring to autumn comparing with that in winter, and difference in NH4-N was largest in spring. At the offing of the mouth of the R. Tama and at the southwestern part of the bay, the concentration of PO4-P bacame lower comparing with those at their circumferences.
On the other hand, in the bottom layer, the concentration of the three nutrients were always high at the northern part of the bay where the Shallows lie. The concentrations of NO3-N and NH4-N in summer and in autumn were lower than those in the other seasons. That of PO4-P took its peak in August and in September, and it was higher than that in the surface layer.
