Document Type



Master of Science (MS)



First Advisor's Name

Evelyn Gaiser

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

William Anderson

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Justin Campbell

Third Advisor's Committee Title

Committee Member


paleolimnology, water transparency, dissolved organic carbon, climate

Date of Defense



Lakes are browning globally from increased inputs of colored dissolved organic carbon (cDOC) driven by climate and land-use change. Browning changes lake ecosystems, especially through reductions in water transparency. I used long-term limnological and plankton records and upper surface sediment diatom assemblages to infer a ~1600-year history of browning from diatom assemblages in a 166 cm core from a subtropical, oligotrophic lake known to experience cyclical browning related to climate oscillations. Diatom assemblages were strongly regulated by cDOC-driven transparency fluctuations in a 14-year plankton dataset (modern model, R2 = 0.62) and in the upper 35 cm of sediments corresponding to a 35-year monitoring record (paleo model, R2 = 0.72). Diatom-inferred transparency and nutrient flux rates show that localized ditching in the 1930’s intensified the effect climate oscillations on transparency causing cyclical browning thereafter. Integrating long-term monitoring and paleobiological research provides valuable ecosystem history for adapting management actions to a changing climate.





Available for download on Friday, December 01, 2023


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