Sedimentary record of sources and accumulation of organic matter in Pyramid Lake, Nevada, over the past 1,000 years

摘要

ew have examined the organic matter contents of two ~210Pb-dated cores of sediment from Pyramid Lake for consequences of the historic environmental and limnological changes that have occurred since modern settlement of this region began in the 1850s. Agricultural diversion of Truckee River water has diminished the volume of this saline, terminal Lake by one-fourth since 1905. Organic C:N ratios, organic δ~13C values, and terrigenous: aquatic n-alkane ratios indicate that the proportion of land-derived organic matter in sediments has decreased as river flow has decreased.