10,000 



I ; 



;■■]-.. J... i-..f- 



X 



o 



>• 



6 



1,000 



all Pine 



iron 



j....f. 



i--f--I--i-"---^ 



100 - 



e> 



3- 



10 



Manganese 



h^.. 



"7 



Zinc \ 



' ' I I ^ ^ 



-i-K.j.'i-i, 



\ I i ^ ' * 



,^- 



I I I 



■ ■ ■ \ I I I 



NOV. JAN, 



1966 1967 



MAR, MAY 



JULY SEPT. NOV, 



Figure 14. — Concentrations of iron, manganese, and zinc in sediment collected monthly from the Tall Pine station (salinity, 

 <1 p.p.t.) in the Newport River estuary. Each value represents the mean and standard deviation of 10 samples. 



greater the competition of ions for sorption 

 sites on the sediment. Thus, physical-chemical 

 properties of the water could cause such a 

 distribution. 



Although the data are preliminary, the con- 

 centrations of zinc, manganese, and iron in 

 the sediments of the Newport River appeared 

 to vary during the sampling period. The trend 

 was for minimum values in the fall and maxi- 

 mum values in the spring and summer. As a 

 result of these findings, we have beguna series 



of laboratory and in situ experiments basedon 

 the technique described in the previous report, 

 to determine which environmental factors in- 

 fluence the rate of exchange of these elements 

 between sediment and water. A knowledge of 

 the total amounts of iron, manganese, and zinc 

 available in the estuary; the rate of exchange 

 of these elements between the sediments and 

 water; and the environmental factors affecting 

 these rates of exchange will allow us to de- 

 scribe the physical movement of iron, man- 

 ganese, and zinc in the Newport River estuary. 



29 



