This research investigates the sensitivity of phytoplankton communities to historical droughts and terrestrial disturbances in northern Wisconsin. Questions that motivate me include: To what extent have disturbances, namely clear-cut logging and forest fire, interacted with droughts over time to influence phytoplankton communities in northern Wisconsin lakes? Did phytoplankton dynamics depend upon site-specific characteristics of the lake, namely the lake's landscape position? To answer these questions, I have collected sediment cores from six lakes situated along a gradient of landscape position. I am reconstructing historical records of fire and phytoplankton community dynamics over the past ~200 years by quantifying charcoal and pigments preserved in sediments and interpreting them together with pollen records and historical records of drought and logging. These records will allow us to describe the influence of landscape position on the sensitivity of phytoplankton to historical disturbances and droughts. This research has benefited from substantial help from collaborators at UW-Madison, the University of Minnesota, and the Ontario Ministry of the Environment, and from several undergraduate students.