A River is super salty. But non salt water and algal mass decay creates an oxygen uptake in the 4m deep lower layer that is defined by a...

A River is super salty. But non salt water and algal mass decay creates an oxygen uptake in the 4m deep lower layer that is defined by a deoxygenation rate of 0.2 day-1 Vertical mixing is lessened so transfers with the oxygenated surface layer (6 mg/L) is described by Dvert = 10^-4 m2/s

- What is the concentration of oxygen at depth?

-If Dvert is now only 10^-5 m2/s, what is the new steady state concentration?