Project at a Glance

Title: Calibration of diatom-pH-alkalinity methodology for the interpretation of the sedimentary record in Emerald Lake, Integrated Watershed Study

Principal Investigator / Author(s): Holmes, Robert

Contractor: UC Santa Barbara

Contract Number: A4-118-32

Research Program Area: Ecosystem & Multimedia Effects

Topic Areas: Acid Deposition, Ecosystem Impacts


The present study was designed to establish quantitative relationships between lake air equilibrated pH, alkalinity, and diatoms occurring in the surface sediments in high elevation Sierra Nevada lakes. These relationships provided the necessary information to develop predictive equations relating lake pH to the composition of surface sediment diatom assemblages in 27 study lakes. Using the Hustedt diatom pH classification system, Index B of Renberg and Hellberg, and multiple linear regression analysis, two equations were developed which predict lake pH from the relative abundance of sediment diatoms occurring in each of four diatom pH groupings. Both equations predicting pH were statistically significant and yielded values of the square of the correlation coefficient of 0.82 and 0.87, respectively. Similar analyses using alkalinity rather than pH as the dependent variable likewise proved statistically significant but with lower values of the square of the correlation coefficient (0.60 and 0.76, respectively).

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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