Figure 28.1 -Bacteria Able to Perform the NH₄⁺ + NO₂⁻ → N₂

Multiple Choice

Figure 28.1

-Bacteria able to perform the NH₄⁺ + NO₂⁻ → N₂ + 2H₂O reaction have been discovered in laboratory bioreactors and wastewater treatment systems.Researchers predicted that these bacteria should exist in oceans.They measured the concentration of NH₄⁺,NO₂⁻,NO₃⁻,and O₂ in the Black Sea as a function of water depth (M.Kuypers et al.2003 Anaerobic ammonium oxidation by anammox bacteria in the Black Sea.Nature 422:
608-11) to determine where in the sea the bacteria might live.Analyzing data presented in Figure 28.1 above,at what depth would you expect to find the bacteria? (Note:
In the figure,different scales are used to show concentrations of NH₄⁺,NO₂⁻,NO₃⁻,and O₂. )

A) in the top 5 meters
B) in the top 50 meters
C) at a depth of 75 meters
D) at a depth of 92 meters
E) below 100 meters