Use of monitoring data to inform paleolimnological records, examples from two lakes in northern California

Description: Paleolimnological proxies serve as a valuable means of providing past lake environmental records that span well beyond the period of historic measurement and monitoring. In the case of diatoms, relative abundance counts are standard practice, and down core changes are interpreted through recognition of biozones, multivariate statistical methods and inference models from known biological data, experimentation, and training sets. Limitations on our interpretations are based on lake sensitivity, and our understanding of the complex interplay of forcings on that diatom community. Limitations are also based on the quality and resolution of age models and the muting of seasonal and annual signals through the lens of multi-annual averaging and sedimentary processes. What part of the signal is lost, even in lakes with “good” age models, and what aspects of monitoring and sampling can best inform us in making paleolimnological interpretations? Examples are explored from core records in both Fallen Leaf lake, Lake Tahoe Basin, and Castle Lake, Siskiyou Mountains of northern California, where multi-year limnological sampling and monitoring datasets exist.

Target audience:
Water managers, policymakers, researchers, and others interested in applying regional diatom data to publicly available tools for assessing biotic integrity.