1. The seasonally averaged sulfate concentration in the porewater of lake sedime
ID: 159141 • Letter: 1
Question
1. The seasonally averaged sulfate concentration in the porewater of lake sediment is 50 µM at the sediment/water interface, but only 5 µM at a depth of 0.2 cm below the interface.
a. How much sulfate can be removed each year from the lake by diffusion into the sediment? Assume an effective diffusion coefficient of 10-6 cm2 s-1, a lake area of 60 Ha and an average depth of 7 m.
b. The lake has an inflow of 5 x 106 m3 yr-1, and sulfate concentration in the inflow is 52 µM. Outflow is 4.5 x 106 m3 yr-1, with a concentration of 50 µM of . Neglecting any other possible sources or sinks of , and assuming the lake to be well-mixed (ie neglect seasonal stratification), estimate the atmospheric input of .
Explanation / Answer
a)
1 Hecta acre =10000 m2
M==(60*104m2)(10-6*10-4m2/s)[(50-5)mol/m3/0.002 m]*(365*24*60*60)*10-3
M=-42573.6 mole/year
b)
Mi=(5*106m3/year)(62*10-3mole/m3)=260000 mole.year
Mo=-(4.5*106 m3/year)(50*10-3 mole/m3) =-225000 mole/year
Ma=Mo-Mi-Ms =225000-260000-42573.6
Ma =-77573.6 mole/year
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.