a biologically driven cryptic cycle was determined by identifying metabolically active sulfate reducing and sulfur oxidizing lineages co-locating within the sediments, effectively masking sulfide production through re-oxidation back to sulfate.

The actual availability of NH4+ and NO3− is difficult to measure in soil. When rates of microbial N transformations and/or plant uptake are rapid, then NH4+ or NO3− levels can be undetectable in soil