8. thermohaline currents are density-driven cur a) are part of the conveyer-belt circulation b) bring oxygen-rich water to the deep ocean c) deposit nutrient-rich water on the surface d) are vertical deep currents e) are all of the answers above 9. upwelling water is downwelling water is a) nutrient rich and oxygen poor; nutrient poor and oxygen rich. b) nutrient poor and oxygen poor; nutrient rich and oxygen rich. c) nutrient poor and oxygen rich; nutrient rich and oxygen poor. d) nutrient rich and oxygen rich; nutrient poor and oxygen poor