In Situ Determination of Detrital Breakdown in Wetland Soil-Floodwater Profile
- Louis A. Schipper and
- K. R. Reddy
The chemical and biological environment in which detritus undergoes breakdown changes markedly with depth through the wetland soil-floodwater profile. However, it has been difficult to quantify the change in breakdown rate with soil depth due to a lack of suitable methodology. We modified porewater equilibrators to measure breakdown of cattail leaves (Typha sp.) at centimeter depth increments through a wetland soil-floodwater profile. During the first week, up to 30% of the plant dry-weight loss occurred at all depths presumably due to leaching, followed by a second phase of breakdown with a further loss of 20 to 30% of initial dry weight in 16 wk. Calculated exponential breakdown constants for the second phase of breakdown were highest in the floodwater (0.0068 d−1) and decreased linearly down the soil profile, with decay constants of <0.003 d−1 at 20 cm below the soil surface. The decrease in the rate of detrital breakdown was partly thought to be driven by decreases in O2 availability. This technique will allow future studies to better quantify organic matter dynamics in wetlands.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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