Implications of a sediment-chemistry study on subalpine marsh conservation in the Lake Tahoe Basin, USA

Abstract

Abstract Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected in 11 subalpine marshes in the Lake Tahoe basin, USA and vicinity in order to trace the effect of anthropogenic impacts on sedimentation and sediment accumulation rates. Cores were 210Pb-dated using a CRS model, and these data were used to calculate sedimentation rates and sediment accumulation rates, which were compared with environmental variables. Age-depth profiles indicated that sedimentation rates changed at different times in different marshes, and we separated sediment cores into two parts to show sediment characteristic and sediment-accumulation-rate changes. Ranges of dry mass accumulation rates and sedimentation rates were 0.081–1.356 kg m−2 yr−1 and 0.94–4.64 mm yr−1 in the upper core and 0.094–0.563 kg m−2 yr−1 and 0.57–1.75 mm yr−1 in the lower core. In general, the cores showed recent increases in sediment accumulation rates. Species composition was related to water quality, ...