2. (20-pt) The figure below (from Jorgensen and Revsbech, 1985) shows the dissolved oxygen profile in water near the seafloor and sediment at a location on the Danish coast. Note the scale of the y-axis. This data was collected with a very small probe. a. (10-pt) What is the flux density, and direction of transport, of O2 in the water-side diffusive boundary layer, if the diffusivity of oxygen in water is Do2,w = 2.0 x 10-5 cm/s? b. (5-pt) Why is the concentration gradient a straight line above the diffusive boundary layer? c. (5-pt) Why do you think the O2 drops off so quickly in the sediment? 02 (umol liter 1) 100 150 200 50 250 1.0 STIRRED SEAWATER 0.5 DIFFUSIVE BOUNDARY LAYER 0.0 02 0.5 1.0 SEDIMENT 1.5 mm 2.0 2. (20-pt) The figure below (from Jorgensen and Revsbech, 1985) shows the dissolved oxygen profile in water near the seafloor and sediment at a location on the Danish coast. Note the scale of the y-axis. This data was collected with a very small probe. a. (10-pt) What is the flux density, and direction of transport, of O2 in the water-side diffusive boundary layer, if the diffusivity of oxygen in water is Do2,w = 2.0 x 10-5 cm/s? b. (5-pt) Why is the concentration gradient a straight line above the diffusive boundary layer? c. (5-pt) Why do you think the O2 drops off so quickly in the sediment? 02 (umol liter 1) 100 150 200 50 250 1.0 STIRRED SEAWATER 0.5 DIFFUSIVE BOUNDARY LAYER 0.0 02 0.5 1.0 SEDIMENT 1.5 mm 2.0