A diatom-inferred water depth transfer function from a single lake in the northern California Coast Range

Abstract

AbstractThis study examines the relationship between diatom assemblages from lake sediment surface samples and water depth at Kelly Lake, California. A total of 40 surface sediment samples (top 5 cm) were taken at various depths within the small (3.4 ha) five-meter-deep lake. Secchi depths, water temperature, pH, salinity, conductivity, and total dissolved solids were also measured. Some diatom species showed distinct association with depth (e.g.,Fragilaria crotonensis, Nitzschia semirobusta). The relationship between the complete diatom assemblages and water depth was analyzed and assessed by depth-constrained cluster analysis, a one-way analysis of similarity, and principal components analysis. Statistically significant differences were found between the assemblages associated with shallow depth (0 m – 1.25 m), mid-depth (1.25 m – 3.75 m), and deep depth (3.75 m – 5.2 m) locations. The relationship between diatom assemblages and lake depth allowed two transfer models to be developed using the Modern Analogue Technique (MAT) and Weighted Averaging Partial Least Squares (WA-PLS). These models were compared and assessed by residual scatter plots. We demonstrate that the diatom assemblages in the sediments of Kelly Lake are differentiated by lake depth. The results indicate that diatom-inferred transfer models based on surface sediment samples from a single lake can be a useful tool for studying past hydroclimatic variability (e.g. lake depth) from cores taken from such lakes in California.