Seston sedimentation in Mirror Lake, New Hampshire, and its relationship to long-term sediment accumulation

Summary

Seston sedimentation into collecting jars 1 m above the basin-filling gyttja was relatively uniform during 3 summers at 3 stations in Mirror Lake, New Hampshire, U. S. A. (overall mean 0.69 g dry wgt · m⁻² · day⁻¹). At the deepwater station (10 m), a mean annual sedimentation of 176 g dry wgt · m² · yr⁻¹ was arrived at by extending the summer rates through autumnal turnover, when measurements failed. The calculated annual deposition of acid-insoluble ash (mainly diatoms and mineral particles) was 93% of the mean rate since 1900, based on a pollen-dated core. This agreement may indicate that transport of additional material to the deeper sediments during autumnal turnover is minor, but the comparison depends on the as-yet-unproven constancy of sedimentation during the last 70 years. Compared to acid-insoluble ash, all chemical elements analysed undergo a remobilization from the surface sediments of 3–69% (Na < Al < K < Ca = S < Mg < C < P < N). Total dry matter decomposes and is remobilized at a rate of 36%.