Which gas's concentration shows a significant decrease as sediment depth increases based on the data presented?

Which gas's concentration shows a significant decrease as sediment depth increases based on the data presented?

• A. Sulfide (S2-)
• B. Carbon dioxide (CO2)
• C. Oxygen (O2)
• D. Ferric iron (Fe3+)

Answer: (C)

As sediment depth increases, the concentration of oxygen (O2) typically shows a significant decrease. This phenomenon occurs because oxygen is consumed by aerobic organisms that reside in the sediment. At greater depths, the availability of light diminishes, and the conditions often become more anaerobic, limiting the presence of oxygen. Consequently, as organic matter decomposes in deeper sediment layers, the oxygen is depleted more rapidly compared to shallower layers where more interactions with the atmosphere and photosynthetic activities can take place. This trend is commonly observed in aquatic environments and contributes to the stratification of different biogeochemical processes occurring in sediments.

As sediment depth increases, the concentration of oxygen (O2) typically shows a significant decrease. This phenomenon occurs because oxygen is consumed by aerobic organisms that reside in the sediment. At greater depths, the availability of light diminishes, and the conditions often become more anaerobic, limiting the presence of oxygen. Consequently, as organic matter decomposes in deeper sediment layers, the oxygen is depleted more rapidly compared to shallower layers where more interactions with the atmosphere and photosynthetic activities can take place. This trend is commonly observed in aquatic environments and contributes to the stratification of different biogeochemical processes occurring in sediments.