Chemistry 125 



TABLE 4-19 Concentration of Dissolved R eactive Phosphorus (DRP), 

 Dissolved Unreactive Phosphorus (DUP), and Particulate 

 Phosphorus (PPj in Accumulated Snow Cover and Precip- 

 itation at Barrow, Alaska* 



Date DRP DUP PP 



Snow cover 

 30 May 71 

 30 May 71 

 30 May 71 

 30 May 71 



Overall mean, winter 1.5 1.1 1.4 



Mixed rain-snow 

 1 August 64 ** 



14 July 71 



Rain 



10 July 71 

 30 July 71 

 10 August 72 



Snow 



15 July 71 

 19 August 71 



Overall mean, summer 7.2 0.7 



*Data are expressed as /L/g P liter 

 **Kalff(1965). 



calculated for a "mean" year with some reference to the effects of 

 extremes. 



As described in Chapter 3, a fraction of the water from winter snow 

 accumulation will be retained during the spring melt to fill the pond to its 

 holding capacity. Over 4 years the winter pond levels have been observed 

 to be to 11 cm below capacity, (a mean of 5.8 cm). The water content of 

 the snow ranged from 6.7 to 16.5 cm in 1971 to 1973 (Table 3-6). With the 

 rare exception of periods after heavy summer rains (e.g., 1973), breakup is 

 the only time in which water actually flows out of the ponds. During 

 breakup, meltwater floods most of the tundra surface and a relatively 

 complicated situation exists in which the concentration of both DRP and 

 DUP is somewhat higher in the ponds than in the water flowing into or 

 away from them, and all of these concentrations are higher than those 

 found in winter precipitation (Table 4-19). At this time of year, dissolved 

 phosphorus is leached rapidly from the vegetation and litter of both 

 terrestrial sites and pond margins. As a result the phosphorus 

 concentration in the meltwater is increased. However, because of the 



