What happens to the concentration of sulfide ion (S2-) as sediment depth increases?

What happens to the concentration of sulfide ion (S2-) as sediment depth increases?

• A. It remains constant.
• B. It increases significantly.
• C. It decreases.
• D. It fluctuates randomly.

Answer: (C)

As sediment depth increases, the concentration of sulfide ion (S2-) generally decreases. This phenomenon is primarily attributed to the processes occurring in sediments, particularly in the context of microbial activity and the availability of organic matter. In shallow sediments, organic material is more abundant, and the decomposition of this material by anaerobic bacteria leads to the production of sulfide ions. As you move deeper into the sediment, the availability of organic matter tends to diminish, resulting in lower metabolic rates and less production of sulfide. Additionally, sulfide can be further oxidized or can bind with metals in deeper layers, leading to decreased concentration levels. Consequently, the combination of diminishing organic matter and increased chemical reactions that consume or sequester sulfide ions causes its concentration to decrease with increasing sediment depth. This reflects a predictable pattern based on sedimentary and biological processes rather than random fluctuations.

As sediment depth increases, the concentration of sulfide ion (S2-) generally decreases. This phenomenon is primarily attributed to the processes occurring in sediments, particularly in the context of microbial activity and the availability of organic matter.

In shallow sediments, organic material is more abundant, and the decomposition of this material by anaerobic bacteria leads to the production of sulfide ions. As you move deeper into the sediment, the availability of organic matter tends to diminish, resulting in lower metabolic rates and less production of sulfide. Additionally, sulfide can be further oxidized or can bind with metals in deeper layers, leading to decreased concentration levels.

Consequently, the combination of diminishing organic matter and increased chemical reactions that consume or sequester sulfide ions causes its concentration to decrease with increasing sediment depth. This reflects a predictable pattern based on sedimentary and biological processes rather than random fluctuations.